Preoperative Evaluation


×
Rating : Rate It:
 
 
priti    on Dec 05, 2013 Says :

nice ppt
Post a comment
    Post Comment on Twitter
Comments:  



  Notes
 
 
1 : Basics of Anesthesia Stoelting and Miller Chapter 13 1 PREOPERATIVE EVALUATIONAND MEDICATION
2 : PREOPERATIVE EVALUATIONAND MEDICATION PREOPERATIVE EVALUATION History Preoperative Physical Examination Overall Assessment of Perioperative Risk American Society of Anesthesiologists Classification 2
3 : PREOPERATIVE EVALUATION AND MEDICATION The Joint Commission for the Accreditation of Healthcare Organizations has mandated that anesthesiologists perform a preoperative evaluation of patients undergoing anesthesia 3
4 : PREOPERATIVE EVALUATION AND MEDICATION American Society of Anesthesiologists (ASA) has adopted standards for preoperative evaluation of patients that include the requirements that an anesthesiologist shall be responsible for Determining the medical status of the patient Developing a plan of anesthesia care Reviewing with the patient or a responsible adult the proposed care plan 4
5 : PREOPERATIVE EVALUATION AND MEDICATION An important aspect of the preoperative visit is: Inform the patient and other interested adults about events to expect on the day of surgery Discuss the risks associated with anesthesia 5
6 : 6
7 : 7
8 : PREOPERATIVE EVALUATION AND MEDICATION History Preoperative evaluation should establish the state of Health of patients Especially their exercise tolerance Their present illness Interactions they have had with their physicians 8
9 : 9
10 : 10
11 : 11
12 : 12
13 : PREOPERATIVE EVALUATION AND MEDICATION History Assessment of mental status should also be made Documentation of the medications patient is taking Any use of drugs, including: Alcohol Tobacco 13
14 : 14
15 : 15
16 : PREOPERATIVE EVALUATION AND MEDICATION History Important to document: Previous anesthetics Whether there were any complications Which surgeries have been performed Any previous medical illnesses 16
17 : PREOPERATIVE EVALUATION AND MEDICATION History Need to be documented Assessment of All drug allergies Family history of malignant hyperthermia 17
18 : PREOPERATIVE EVALUATION AND MEDICATION History Documentation of Significant patient wishes Including prohibition of Administration of blood – Jehovah’s Witnesses Suspension of do-not resuscitate orders Needs to be made 18
19 : PREOPERATIVE EVALUATION AND MEDICATION History Goals of the preoperative evaluation are to: Inform the patient of the risk so that an informed consent can be made Educate the patient regarding the anesthesia Events to take place in the peri-operative period Answer questions and reassure the patient and family Notify the patient about the prohibition of ingesting food Instruct the patient about which medication to take on the day of surgery or which medications to stop taking 19
20 : PREOPERATIVE EVALUATION AND MEDICATION History Final goal: Use the operative experience to motivate the patient More optimal health Improved health outcomes 20
21 : PREOPERATIVE EVALUATION AND MEDICATION History Examples of this last goal are Encourage patients to stop smoking before and after their procedures Administer ß-adrenergic receptor blocking agents to patients at risk for cardiac complications 21
22 : PREOPERATIVE EVALUATION AND MEDICATION History Questions that should be addressed include the following: Is the patient in optimal health? Can or should the patient’s physical or mental condition be improved before surgery? Does the patient have any health problems or use any medication that could unexpectedly influence perioperative events? 22
23 : PREOPERATIVE EVALUATION AND MEDICATION Preoperative Physical Examination Preoperative physical examination needs to include: Evaluation of the airway Cardiovascular status of the patient, including Assessment of body mass index Systemic blood pressure Hemoglobin saturation with oxygen Examination of the heart and lungs 23
24 : 24
25 : 25
26 : PREOPERATIVE EVALUATION AND MEDICATION Preoperative Physical Examination Routine preoperative laboratory tests need not be ordered if Patient is in optimal medical condition for daily living Procedure is minimally invasive 26
27 : 27
28 : PREOPERATIVE EVALUATION AND MEDICATION Preoperative Physical Examination Preoperative laboratory testing Fails to uncover pathologic conditions Inefficient in screening for abnormalities in asymptomatic patients Routine laboratory tests in patients at low risk Rarely beneficial Should be ordered only when a patient is Symptomatic Has a specific disease 28
29 : 29
30 : 30
31 : PREOPERATIVE EVALUATION AND MEDICATION Preoperative Physical Examination Optimal preoperative assessment requires Complete history Physical examination Determines whether patient has an abnormality that warrants laboratory tests 31
32 : PREOPERATIVE EVALUATION AND MEDICATION Preoperative Physical Examination Information obtained during the preoperative evaluation Needs to be available to the surgeon Needs to be available anesthesiologist who delivers the anesthetic Often accomplished through electronic information systems Perioperative interventions Including administration of ß-blockers – need to be continued Information needs to be available in the patient’s record 32
33 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Perioperative risk encompasses Risks that the patient brings to the procedure because of health problems Risk associated with the planned surgery Including its impact on the function of organs Interaction of the Anesthesia Patient Surgery 33
34 : 34
35 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Greater the number of patients with whom anesthesiologists and surgeons have interacted for specific procedures Less the perioperative risk for the patient May be due to Increased skill of the anesthesiologists and surgeons Also the knowledge and availability of the staff involved in the perioperative care of the patients 35
36 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Investigation from Britain in 1987 Documented a 30-day crude mortality rate after surgery and anesthesia About 0.8% Anesthesia was considered to be the sole cause of death in only 1 in 185,000 cases Major contributor to death in 7 of 10,000 cases 36
37 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Between 1992 and 1994 Peri-operative deaths within 48 hours of an operation Occurred in 347 of 184,472 patients About 0.2% 37
38 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Mortality was attributed to anesthesia-related events About 1 in 13,322 procedures (a rate of 0.01%) in an urban hospital setting More often in patients with underlying illnesses Anesthesia-related mortality is very low 38
39 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Investigations suggest: Equipment failure is a very minor cause of anesthesia mishaps Human error is the major cause of anesthesia-related problems Associated with increased risk Emergency surgery Vascular surgery 39
40 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Procedures involving large blood loss or fluid shifts Considered high-risk surgeries Often have an incidence of cardiac death and nonfatal myocardial infarction Greater than 5% 40
41 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Ophthalmologic surgery and surgeries that are superficial or involve endoscopy Extremely safe and have an incidence of cardiac death and nonfatal myocardial infarction Less than 1% 41
42 : PREOPERATIVE EVALUATION AND MEDICATION Overall Assessment of Perioperative Risk Intermediate-risk surgeries include Carotid surgery Head and neck surgery Intra-peritoneal surgery Intra-thoracic surgery Orthopedic surgery Prostate surgery 42
43 : PREOPERATIVE EVALUATION AND MEDICATION American Society of Anesthesiologists Classification ASA Physical Status classification allows an overall description of the status of the patient and correlates well with patient outcomes 43
44 : 44
45 : 45
46 : PREOPERATIVE EVALUATIONAND MEDICATION CLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Clinical Predictors of Cardiac Risk Pharmacologic Preoperative Prophylaxis Coronary Revascularization Guidelines 46
47 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pre-operative history should characterize Duration Severity Stability Of cardiopulmonary symptoms 47
48 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Patient’s baseline functional status – informative Should decipher whether functional limitations are cardiac in etiology, or Due to other conditions Claudication Pulmonary disease Arthritis Deconditioning 48
49 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Cardiac risk factors must be identified Age Male gender Cigarette smoking Diabetes mellitus Hypercholesterolemia Systemic hypertension Obesity Sedentary lifestyle Family history of coronary artery disease 49
50 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Baseline electrocardiogram reviewed for: Evidence of previous myocardial infarction Ischemic changes Conduction abnormalities Left ventricular hypertrophy 50
51 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Additional testing should be considered if indicated by the history or physical examination Only if the test results will alter the patient’s management Surgery itself is also important to consider Prolonged procedures (>5 hours) Urgent surgeries Major thoracic Major abdominal Vascular surgeries Considered higher risk 51
52 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Clinical Predictors of Cardiac Risk Several investigations have identified major risk factors for perioperative cardiac complications Peri-operative cardiac events have been associated with six independent variables 52
53 : 53
54 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Clinical Predictors of Cardiac Risk Patients with more than two variables Moderate (7%) to high risk (11%) for perioperative cardiac events 54
55 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis ß-BLOCKERS Evidence supports perioperative administration of ß-blockers Decreases cardiac events and mortality Randomized controlled trial of 200 patients with Coronary artery disease or cardiac risk factors Undergoing non- cardiac surgery 55
56 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis ß-BLOCKERS Documented a significant decrease in Cardiovascular mortality Higher event-free survival rates In patients treated peri-operatively with atenolol versus placebo 56
57 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis ß-BLOCKERS Principal effect attributed to Decrease in cardiovascular mortality Observed in the first 6 to 8 months Survival benefit persisted over the 2-year follow-up period 57
58 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis ß-BLOCKERS To determine the effects of perioperative ß-blockade on vascular surgery patients Randomized multicenter trial examined the effect of bisoprolol on cardiac-related mortality and nonfatal myocardial infarction within 30 days of major vascular surgery in high-risk patients 58
59 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis ß-BLOCKERS High risk defined as presence of at least one cardiac risk factor: Age >70 years Angina Previous myocardial infarction by history or Q waves on the electrocardiogram Compensated congestive heart failure or a history of congestive heart failure Current treatment of ventricular dysrhythmias Current treatment of diabetes mellitus Limited exercise capacity Dobutamine echocardiography consistent with inducible ischemia 59
60 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis ß-BLOCKERS Significantly decreased rates of cardiac-related mortality and non-fatal myocardial infarction in the bisoprolol group Resulted in premature termination of the trial by the study’s safety committee 60
61 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis ß-BLOCKERS Dose of ß-blocker Titrated to a target resting heart rate of less than 65 beats/min ß-Blockers should be Avoided in patients with asthma Used judiciously in those with chronic obstructive pulmonary disease (COPD) When spirometry demonstrates a significant bronchodilator response 61
62 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis a2-AGONISTS If ß-blockers are contraindicated in patients at risk for perioperative cardiac complications a2-agonists Clonidine Dexmedetomidine Mivazerol Should be considered as an alternative for cardio-protection 62
63 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis a2-AGONISTS a2-Agonists have also been shown to reduce peri-operative cardiac events Myocardial ischemia After Cardiac Non-cardiac surgery Vascular surgery 63
64 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis a2-AGONISTS a2-Agonists may provide these benefits by Dilation of post-stenotic coronary arteries Mitigation of peri-operative hemodynamic disturbances 64
65 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Pharmacologic Preoperative Prophylaxis a2-AGONISTS a2-agonists provide Pain relief Decreasing the need for analgesics Not known whether combination therapy with an a2-agonist and ß-blocker Produces an additive or synergistic effect 65
66 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Coronary Revascularization Data fail to show any benefit from coronary artery revascularization by Coronary artery bypass grafting (CABG) Percutaneous coronary artery (PTCA intervention) For the sole purpose of reducing peri-operative cardiac events 66
67 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Coronary Revascularization Coronary artery revascularization should be Reserved for patients who have indications for the procedure (patients with advanced coronary artery disease in whom CABG may provide a survival benefit or cardiac symptoms that are unstable or refractory to medical therapy) Independent of the planned surgery 67
68 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Coronary Revascularization Patients who have undergone percutaneous coronary artery stenting preoperatively for independent indications Elective non-cardiac surgery should be deferred for a minimum of 6 weeks – allows Endothelialization of the stents Completion of anti-platelet therapy 68
69 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Guidelines Practice guidelines for perioperative cardiovascular risk assessment have been published American College of Cardiology/American Heart Association Task Force published guidelines Emphasized preoperative intervention seldom necessary unless clinically indicated independent of surgery Should be limited to patients who are likely to benefit from such testing, intervention, or therapy 69
70 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Guidelines Another algorithm based on clinical predictors Major Intermediate Minor Including: Previous cardiovascular evaluation and treatment Functional capacity (defined in metabolic equivalents) Risks specific for intended surgery If indicated – results of noninvasive cardiac testing 70
71 : PREOPERATIVE EVALUATION AND MEDICATIONCLINICAL EVALUATION OF PATIENTS FOR CARDIAC RISK Guidelines Alternative strategy has been advocated Reduce the risk for cardiac events with Pharmacologic therapy Rather than simply categorizing a patient as Low Intermediate High risk 71
72 : PREOPERATIVE EVALUATIONAND MEDICATION PREOPERATIVE EVALUATION OF PATIENTS WITH PULMONARY DISEASE Risk Factors for Postoperative Pulmonary Complications Chest Radiograph Pulmonary Function Testing 72
73 : PREOPERATIVE EVALUATION AND MEDICATION Postoperative pulmonary complications for those undergoing abdominal surgery Estimated that 5% to 10% of all surgical patients 9% to 40% will experience complications Postoperative pulmonary complications in nonthoracic surgery Associated with significant morbidity Increase the length of hospitalization 73
74 : PREOPERATIVE EVALUATION AND MEDICATION First step in reducing postoperative pulmonary complications Identify patients at increased risk 74
75 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications Although the clinical significance varies Several issues grouped together in studies of risk factors for postoperative pulmonary complications: Atelectasis Postoperative pneumonia Acute respiratory distress syndrome (ARDS) Postoperative respiratory failure 75
76 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications Mild to moderate obesity as a risk factor for postoperative pulmonary complications Remains controversial Obese patients often have a higher incidence of comorbid conditions Contribute to the risk for pulmonary complications 76
77 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications Pulmonary complications after non-thoracic surgery More frequent than cardiac complications Associated with greater increases in hospital length of stay 77
78 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications Most studies have reported a lower risk for pulmonary complications with Epidural or spinal anesthesia Than with general anesthesia For surgery patients at high risk for pulmonary complications Reasonable to consider Spinal anesthesia Epidural anesthesia Regional block anesthesia 78
79 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications POSTOPERATIVE RESPIRATORY FAILURE Postoperative respiratory failure Commonly defined as inability to extubate the patient’s trachea 48 hours after surgery Risk factors for postoperative respiratory failure Divided into Patient specific Surgery specific 79
80 : 80
81 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications POSTOPERATIVE RESPIRATORY FAILURE 30-day death rate in patients with postoperative respiratory failure Much higher than that in patients not experiencing this complication 27% versus 1% 81
82 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications POSTOPERATIVE RESPIRATORY FAILURE Principal patient-specific risk factors for postoperative respiratory failure Renal status Fluid status Preoperative respiratory 82
83 : 83 *Other surgeries include ophthalmologic, ear, nose, mouth, lower abdominal, extremity, dermatologic, spine, and back surgery. Adapted from Arozullah AM, Daley J, Henderson WG, Khuri SF. National Veterans Administration Surgical Quality Improvement Program. Ann Surg 2000;232:242-253.
84 : 84 *Other surgeries include ophthalmologic, ear, nose, mouth, lower abdominal, extremity, dermatologic, spine, and back surgery. Adapted from Arozullah AM, Daley J, Henderson WG, Khuri SF. National Veterans Administration Surgical Quality Improvement Program. Ann Surg 2000;232:242-253.
85 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications POSTOPERATIVE RESPIRATORY FAILURE Respiratory Risk Index Score Respiratory risk index score Used to predict the probability of postoperative respiratory failure 85
86 : 86 Adapted from Arozullah AM, Daley J, Henderson WG, Khuri SF. National Veterans Administration Surgical Quality Improvement Program. Ann Surg 2000;232:242-253.
87 : 87 *Phase I included patients enrolled between October 1, 1991, and December 31, 1993, at 44 Veterans Affairs Medical Centers (VAMC). Phase II included patients enrolled between January 1, 1994, through August 31, 1995, at all 132 VAMCs that perform surgery. †Number of phase I subjects in each risk class. PRF, postoperative respiratory failure; RF, respiratory failure. Adapted from Arozullah AM, Daley J, Henderson WG, Khuri SF. National Veterans Administration Surgical Quality Improvement Program. Ann Surg 2000;232:242-253.
88 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications POSTOPERATIVE RESPIRATORY FAILURE Respiratory Risk Index Score Risk index score Permits general estimates of risk in patients undergoing a variety of surgical procedures Does not include data from Physical examination Pulmonary function tests Commonly used to assist in risk prediction before surgery 88
89 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications POSTOPERATIVE RESPIRATORY FAILURE Respiratory Risk Index Score Ability of the risk score index to predict postoperative respiratory failure in predominantly healthy patients undergoing elective non-thoracic surgery Uncertain because the data used to develop this index were from patients who were: All males High burden of comorbid conditions Almost a third of the surgeries were intra-thoracic or performed on an emergency basis 89
90 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications SITE OF SURGERY Risk for postoperative respiratory complications Most strongly related to the surgical site Risk increases as the incision approaches the diaphragm Upper abdominal and thoracic surgery carries greatest risk for postoperative pulmonary complications Range from 10% to 40% 90
91 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications SITE OF SURGERY Risk is much lower for laparoscopic cholecystectomy (0.3% to 0.4%) Than for open cholecystectomy (13% to 33%) 91
92 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications CHRONIC OBSTRUCTIVE PULMONARY DISEASE Patients with COPD Increased risk for postoperative pulmonary complications Patient treated aggressively before surgery if they do not have Optimal reduction of symptoms and airflow obstruction Optimal exercise capacity 92
93 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications CHRONIC OBSTRUCTIVE PULMONARY DISEASE Limited data on the pre-operative benefit of Individual drugs Combination of bronchodilators Physical therapy Antibiotics Smoking cessation Corticosteroids may reduce the risk for postoperative pulmonary complications in this patient population 93
94 : PREOPERATIVE EVALUATION AND MEDICATION Risk Factors for Postoperative Pulmonary Complications CHRONIC OBSTRUCTIVE PULMONARY DISEASE Incidence of peri-operative bronchospasm Increased in patients with asthma Patients should be free of wheezing 94
95 : PREOPERATIVE EVALUATION AND MEDICATION Chest Radiograph Routine preoperative chest radiographs Still widely used Preponderance of the evidence does not support their broad utilization 95
96 : PREOPERATIVE EVALUATION AND MEDICATION Chest Radiograph Retrospective study conducted to evaluate a protocol for selective ordering of preoperative chest radiographs According to Patient’s clinical status Medical history Scheduled surgery Showed abandonment of routine ordering of preoperative chest x-rays No effects on patient care 96
97 : PREOPERATIVE EVALUATION AND MEDICATION Chest Radiograph Patients who received preoperative chest radiographs 15% considered useful by anesthesiologist 5% had an impact surgical plan or anesthetic management ASA stated Chest radiographs not indicated on basis of age or preexisting respiratory condition, unless A surgical indication Clear clinical change Need to establish the presence or absence of a defined pulmonary condition 97
98 : PREOPERATIVE EVALUATION AND MEDICATION Pulmonary Function Testing There is consensus that all candidates for lung resection should undergo preoperative pulmonary function testing Testing should be performed selectively in patients undergoing other surgical procedures Clinical findings Generally more predictive of pulmonary complications Rather than results obtained from pulmonary function studies 98
99 : PREOPERATIVE EVALUATION AND MEDICATION Pulmonary Function Testing Patients at high risk as defined by pulmonary function studies May undergo surgery with an acceptable risk for pulmonary complications Pulmonary function studies may be helpful in patients with COPD or asthma If it remains uncertain whether the degree of airflow obstruction has been optimally reduced 99
100 : PREOPERATIVE EVALUATION AND MEDICATION Pulmonary Function Testing Results of preoperative pulmonary function testing alone Should not cancel non-thoracic surgery 100
101 : PREOPERATIVE EVALUATIONAND MEDICATION PREOPERATIVE EVALUATION OF PATIENTS WITH PULMONARY DISEASE Arterial Blood Gases Preventive Strategies Smoking Cessation Prevention of Venous Thromboembolism 101
102 : PREOPERATIVE EVALUATION AND MEDICATION Arterial Blood Gases PaCO2 higher than 45 mm Hg Strong risk factor for pulmonary complications Another report Elevated PaCO2 not associated with Increased mortality Increased morbidity In surgical patients undergoing lung resection 102
103 : PREOPERATIVE EVALUATION AND MEDICATION Arterial Blood Gases Arterial blood gas analysis alone Should not be used to exclude patients from surgery 103
104 : PREOPERATIVE EVALUATION AND MEDICATION Preventive Strategies Some variability in the risk factors for postoperative pulmonary complications Several risk reduction strategies intended to provide optimal lung mechanics Lung expansion maneuvers Pain control 104
105 : PREOPERATIVE EVALUATION AND MEDICATION Preventive Strategies Lung expansion maneuvers studied extensively: Deep-breathing exercises Component of chest physical therapy Incentive spirometry Preoperative education in lung expansion maneuvers Reduces postoperative pulmonary complications to a greater degree than Instruction that begins after surgery 105
106 : PREOPERATIVE EVALUATION AND MEDICATION Preventive Strategies Intermittent positive-pressure breathing Continuous positive airway pressure – though effective Not recommended routinely because of High cost Risk for treatment-associated complications 106
107 : PREOPERATIVE EVALUATION AND MEDICATION Smoking Cessation Risk for postoperative pulmonary complications Smokers vs. nonsmokers Greatly increased Length of preoperative smoking cessation necessary to decrease risk Not clear 107
108 : PREOPERATIVE EVALUATION AND MEDICATION Smoking Cessation Generally accepted Increased incidence of postoperative pulmonary complications in smokers Reduced significantly – stop smoking before surgery No consensus on minimal or optimal duration of preoperative abstinence 108
109 : PREOPERATIVE EVALUATION AND MEDICATION Smoking Cessation Carbon monoxide and nicotine elimination Occurs after 12 to 24 hours Major benefit from discontinuing smoking Decrease in carboxy-hemoglobin content Better oxygen availability to tissues 109
110 : PREOPERATIVE EVALUATION AND MEDICATION Smoking Cessation Also evidence that the sensitive upper airway reflexes of smokers Reduced by abstinence Few days smoking cessation May greatly improve ciliary beating 1 to 2 weeks provides a significant reduction in sputum volume 110
111 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism Patients undergoing general surgery without thromboprophylaxis Rates of deep vein thrombosis and fatal pulmonary embolism Range from 15% to 30% and from 0.2% to 0.9%, respectively 111
112 : 112
113 : 113 *Thrombophilia includes factor V Leiden, prothrombin variant mutations, anticardiolipin antibody syndrome, antithrombin, protein C or protein S deficiency, hyperhomocysteinemia, and myeloproliferative disorders.BMI, body mass index; CHF, congestive heart failure; DVT, deep vein thrombosis; IBW, ideal body weight; MI, myocardial infarction; PE, pulmonary embolism. Adapted from the UCSF Medical Center Adult Venous Thromboembolism Risk Assessment and Prophylaxis Order Form.
114 : 114 Adapted from Gutt CN, Oniu T, Wolkener F, et al. Prophylaxis and treatment of deep vein thrombosis in general surgery. Am J Surg 2005;189:14-22.
115 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism Prevention strategies include us of: Low-dose unfractionated heparin Low-molecular-weight heparin Intermittent pneumatic compression stockings 115
116 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism Use of graded compression elastic stockings alone Associated with a 44% reduction in risk Most effective therapies in reducing the incidence of deep vein thrombosis Low-dose unfractionated heparin Low-molecular-weight heparin 68% to 76% reduction in risk 116
117 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism The two heparin preparations appear to be equally effective in preventing deep vein thrombosis in general surgery patients Discrepant findings in regard to Bleeding complications associated with each therapy 117
118 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism Some studies reported significantly fewer Wound hematomas Bleeding complications With low-molecular-weight heparin Other trials have shown that low-molecular-weight heparin causes more bleeding than low-dose un-fractionated heparin 118
119 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism Routine use of thromboprophylaxis recommended in Surgical patients older than 40 years, or Undergoing major surgical procedures Type and duration of surgery Clearly influences risk for deep vein thrombosis Most individuals undergoing outpatient surgery Low frequency of deep vein thrombosis 119
120 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism When compared with no thromboprophylaxis, both Subcutaneous low-dose unfractionated heparin Low molecular- weight heparin Shown to reduce risk for pulmonary embolism by at least 60% 120
121 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism Moderate-risk patients Fixed low-dose unfractionated heparin 5000 units every 12 hours Low-molecularweight heparin 3400 anti–factor Xa units or equivalent Once daily is sufficient 121
122 : PREOPERATIVE EVALUATION AND MEDICATION Prevention of Venous Thromboembolism Compression elastic stockings are effective when used alone in moderate-risk patients in whom anticoagulants are contraindicated 122
123 : PREOPERATIVE EVALUATIONAND MEDICATION PREOPERATIVE MEDICATION Psychological Preparation Pharmacologic Premedication Drugs Administered for Pharmacologic Premedication Premedication for Outpatients 123
124 : PREOPERATIVE EVALUATION AND MEDICATION Management of anesthesia begins with Preoperative psychological preparation of the patient Administration of a drug or drugs selected to elicit specific pharmacologic responses Initial psychological and pharmacologic component of anesthetic management is referred to as Preoperative medication 124
125 : PREOPERATIVE EVALUATION AND MEDICATION All patients should enter the preoperative period free of Anxiety Sedated but easily arousable Fully cooperative 125
126 : PREOPERATIVE EVALUATION AND MEDICATION Psychological Preparation Psychological preparation is provided by Anesthesiologist’s preoperative visit Interview with patient and family members Incidence of anxiety Lower in patients visited by the anesthesiologist preoperatively vs Those receiving only pharmacologic premedication and no visit 126
127 : PREOPERATIVE EVALUATION AND MEDICATION Psychological Preparation Shortage of time Some patients’ problems do not lend themselves to reassurance May limit the anxiolytic value of the preoperative interview 127
128 : PREOPERATIVE EVALUATION AND MEDICATION Pharmacologic Premedication Pharmacologic premedication Typically administered orally or intramuscularly 1 to 2 hours before anticipated induction of anesthesia Outpatient surgery Premedication may be administered intravenously in the immediate preoperative period 128
129 : PREOPERATIVE EVALUATION AND MEDICATION Pharmacologic Premedication Goals of pharmacologic premedication Multiple Must be individualized to meet each patient’s unique requirements Multiple different drugs or combinations of drugs Selected to achieve the same goals 129
130 : 130
131 : 131
132 : PREOPERATIVE EVALUATION AND MEDICATION Pharmacologic Premedication Appropriate drug or drugs and doses used for pharmacologic premedication Selected after the psychological and physiologic condition of patient evaluated 132
133 : 133
134 : 134 *Doses are to be titrated to patient’s condition and age. **24 hours for full effect. †Rare incidence of prolonged QT interval on the electrocardiogram. IM, intramuscular; IV, intravenous.
135 : 135
136 : PREOPERATIVE EVALUATION AND MEDICATION Pharmacologic Premedication Multiple factors must take into account to determine Choice of drug and dose Certain types of patients should not receive depressant pharmacologic drugs Attempting to decrease preoperative anxiety and produce sedation 136
137 : 137
138 : PREOPERATIVE EVALUATION AND MEDICATION Pharmacologic Premedication Patient who requests to be “asleep” before being transported to the operating room Must be assured that this is neither a desired nor a safe goal of pharmacologic premedication 138
139 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication Several classes of drugs are available Facilitate achievement of desired goals for pharmacologic premedication Drugs administered orally if possible As opposed to intramuscularly to improve patient comfort Small volume of water (up to 150 mL) used to facilitate oral administration of drugs No hazards related to gastric fluid volume 139
140 : 140
141 : 141 *Doses are to be titrated to patient’s condition and age. **24 hours for full effect. †Rare incidence of prolonged QT interval on the electrocardiogram. IM, intramuscular; IV, intravenous.
142 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication Selection of specific drugs Based on a consideration of the desirable goals to be achieved Balanced against any potential undesirable effects of these drugs 142
143 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication BENZODIAZEPINES Benzodiazepines Most commonly administered drugs before elective surgery for Production of sedation Relief of anxiety Act on specific brain receptors Produce selective anxiolytic effects – doses do not produce: Excessive sedation Cardiopulmonary depression 143
144 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication BENZODIAZEPINES Midazolam and lorazepam Produce suppression of recall of events that occur After their administration (anterograde amnesia) Disadvantages of benzodiazepines as used for pharmacologic premedication include Excessive and prolonged sedation Occasional patients 144
145 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication BENZODIAZEPINES Flumazenil Specific benzodiazepine antagonist Effective in reversing Undesirable or unacceptably Persistent effects of these drugs Benzodiazepines administered for preoperative medication May interfere with the release of cortisol in response to stress Effect not widely appreciated 145
146 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Advantages of opioids for pharmacologic premedication include Absence of direct myocardial depression Production of analgesia in patients experiencing pain Preoperatively Require insertion of invasive monitors before induction of anesthesia Institution of a regional anesthetic 146
147 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Administration f an opioid in the preoperative medication (preemptive analgesia) May decrease need for parenteral analgesics in the early postoperative period 147
148 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Morphine and meperidine Most commonly used opioids for pharmacologic premedication Morphine Well absorbed after intramuscular injection Peak effect in 45 to 90 minutes 148
149 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Morphine After intravenous administration Peak effect of morphine Within 20 minutes In the preoperative medication Decreases undesirable increases in heart rate accompanying Surgical stimulation during the administration of volatile anesthetics 149
150 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Pharmacologic premedication - intramuscular administration of opioids Reasonable when a nitrous oxide–opioid anesthetic is planned Opioid may be given intravenously immediately Before the induction of anesthesia Fentanyl often administered intravenously Immediately before induction of anesthesia 150
151 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Adverse effects of opioids Depression of the medullary ventilatory center Evidenced by Decreased responsiveness to carbon dioxide Orthostatic hypotension Secondary to relaxation of peripheral vascular smooth muscle 151
152 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Orthostatic hypotension Further exaggerated if opioids are administered to patients with decreased intravascular fluid volume Nausea and vomiting Reflects opioid-induced stimulation of the chemoreceptor trigger zone in the medulla 152
153 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Delayed gastric emptying produced by morphine May alter the rate of absorption of : Orally administered drugs Increase the risk for pulmonary aspiration Result in nausea and vomiting 153
154 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Recumbency Minimizes nausea and vomiting after the administration of opioids Suggests stimulation of the vestibular apparatus Important in production of this undesirable effect 154
155 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Opioids may be avoided in patients Undergoing outpatient surgery Operations known to be associated with high incidence of nausea and vomiting Gynecologic operations Ophthalmologic operations 155
156 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Opioid-induced smooth muscle constriction Manifested as choledochoduodenal sphincter spasm Some anesthesiologists question use of opioids in patients with biliary tract disease Pain associated with opioid-induced biliary tract spasm Difficult to differentiate from angina pectoris 156
157 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Nitroglycerin will relieve any pain associated with both conditions Administration of an opioid antagonist Naloxone Relieves only the pain that is due to opioid-induced biliary tract spasm 157
158 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication OPIOIDS Annoying side effect of opioids Pruritus Particularly prominent around the nose 158
159 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIHISTAMINES Antihistamines Occasionally used for pharmacologic premedication Sedative properties Antiemetic properties Promethazine New warning from the FDA Associated with apnea in children and deaths 159
160 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIHISTAMINES Prophylaxis against Allergic Reactions Diphenhydramine – 25 to 50 mg orally Recommended as pharmacologic premedication Provides prophylaxis against intraoperative allergic reactions Patients who have a history of chronic atopy Undergoing procedures (radiographic dye studies) Associated with allergic reactions 160
161 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIHISTAMINES Prophylaxis against Allergic Reactions H2 antagonist - Cimetidine (300 mg orally) Administered with diphenhydramine Combination of H1 antagonist (diphenhydramine) H2 antagonist (cimetidine) Occupies peripheral receptor sites normally responsive to histamine Decreases manifestations of subsequent drug-induced release of histamine 161
162 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIHISTAMINES Prophylaxis against Allergic Reactions Prednisone (50 mg orally or other doses) Added to prophylactic regimen Even with this prophylactic regimen Drug-induced allergic reactions may still occur Highly sensitive patients 162
163 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication a2-AGONISTS Clonidine Centrally acting a2-agonist Acts as an antihypertensive drug Administered as preoperative medication 0.1 mg bid or 0.1 mg patch 163
164 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication a2-AGONISTS Clonidine produces: Sedation and attenuation of the autonomic nervous system reflex responses Hypertension Tachycardia Catecholamine release Associated with Preoperative anxiety Surgical stimulation 164
165 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication a2-AGONISTS Clonidine – titrate to desired effect In preoperative medication Decrease the incidence of preoperative myocardial ischemia in patients with coronary artery disease Suspected Documented 165
166 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication a2-AGONISTS Dose requirements for inhaled and injected anesthetics Decreased in patients receiving clonidine as preoperative medication Possible side effects when a2-agonists Bradycardia Dry mouth 166
167 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIEMETICS Nausea and vomiting Unpleasant symptoms Rarely harm patients Prophylactic administration of antiemetic Recommended to decreasing incidence of postoperative nausea and vomiting 167
168 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIEMETICS Patients at high risk for nausea and vomiting Females undergoing gynecologic operations Patients undergoing ophthalmologic operations 168
169 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIEMETICS Drugs used for prophylaxis against postoperative nausea and vomiting Serotonin antagonists Ondansetron Tropisetron Granisetron dolasetron 169
170 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIEMETICS Drugs used for prophylaxis against postoperative nausea and vomiting – continued Gastrointestinal prokinetics Metoclopramide Phenothiazines Perphenazine 170
171 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIEMETICS Drugs used for prophylaxis against postoperative nausea and vomiting – continued Butyrophenone Droperidol Proven effective antiemetic Clinical use tempered by concern Drug may increase the QT interval 171
172 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTIEMETICS Antiemetics Often administered intravenously before end of surgery Disadvantages of routine prophylactic administration of antiemetics: Increased cost, especially if serotonin antagonists administered Orthostatic hypotension Some patients vomit with or without prophylaxis 172
173 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Routine inclusion of anticholinergics Not necessary Most frequent reasons for administering anticholinergics Production of an antisialagogue effect Counteracting saliva formation Production of sedative and amnesic effects Prevention of reflex bradycardia 173
174 : 174 0, none; +, mild; ++, moderate; +++, marked. Mydriasis - Prolonged abnormal dilatation of the pupil of the eye caused by disease or a drug. Cycloplegia - paralysis of the ciliary muscle.
175 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Anticholinergics have inherent side effects Need to be considered when selecting preoperative medication Anticholinergics not predictably effective in Increasing gastric fluid pH Decreasing gastric fluid volume 175
176 : 176
177 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect Need for including an anticholinergic in preoperative medication Questioned as currently used inhaled and injected anesthetics Do not stimulate excessive upper airway secretions Ketamine being an exception 177
178 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect Decrease in secretions during general anesthesia Desirable effect of an anticholinergic administered preoperatively Particularly when a tracheal tube is in place 178
179 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect Antisialagogue effect particularly important for Intraoral operations Bronchoscopy When topical anesthesia is necessary Excessive secretions may Interfere with the surgery impair production of topical anesthesia by diluting the local anesthetic 179
180 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect Administration of anticholinergic for an antisialagogue effect Not necessary when regional anesthesia is planned 180
181 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect Scopolamine About three times more potent as antisialagogue than atropine Often selected for both Antisialagogue effect Sedation Desired results of preoperative medication 181
182 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect Glycopyrrolate About twice as potent as atropine Longer duration of action Glycopyrrolate preferentially selected when Antisialagogue effect Absence of sedation is desired 182
183 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect To decrease period of discomfort from a dry mouth and throat Anticholinergic administered Intramuscularly Just before the patient is transported to operating room Intravenously Just before induction of anesthesia 183
184 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Antisialagogue Effect Dry mouth and throat – even in the absence of an anticholinergic May be caused by Anxiety Fluid deprivation before elective surgery Other drugs used for pharmacologic premedication may produce this effect 184
185 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Sedative and Amnesic Effects Atropine and scopolamine Tertiary amines that cross lipid barriers Including the blood-brain barrier Resulting sedative and amnesic effects Reflect penetrance of these drugs into the central nervous system 185
186 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Sedative and Amnesic Effects Scopolamine Produces useful sedative effects More than atropine Particularly in combination with Benzodiazepines Opioids Sedative and amnesic effects of scopolamine 8 to 10 times greater than atropine 186
187 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Sedative and Amnesic Effects Glycopyrrolate Quaternary ammonium compound Cannot easily cross the blood-brain barrier Does not produce significant sedative or amnesic effects 187
188 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Prevention of Reflex Bradycardia Use of anticholinergics for prevention of reflex bradycardia Secondary objective Dose and timing of intramuscular administration not appropriate for the period when bradycardia is most likely to occur 188
189 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Prevention of Reflex Bradycardia Logical approach Administer atropine or glycopyrrolate intravenously shortly before the anticipated need Particularly in children with increased vagal activity 189
190 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Prevention of Reflex Bradycardia Bradycardia Observed after induction of anesthesia with propofol Recommend prior intravenous injection of atropine when vagal stimulation is likely to occur in association with the use of this intravenous anesthetic 190
191 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Undesirable Side Effects Undesirable side effects of anticholinergics – multiple Must be considered in decision to use these drugs for pharmacologic premedication 191
192 : 192
193 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Undesirable Side Effects – Central Nervous System Toxicity Central nervous system toxicity produced by anticholinergics AKA – Central anticholinergic syndrome Manifested as Delirium after anesthesia Prolonged somnolence after anesthesia Somnolence - sleepiness: a very sleepy state 193
194 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Undesirable Side Effects – Central Nervous System Toxicity Undesirable response More likely to follow the administration of scopolamine than atropine Incidence – low with doses used for pharmacologic premedication Elderly patients Uniquely susceptible to central nervous system toxicity Secondary to atropine or scopolamine administration 194
195 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Undesirable Side Effects – Central Nervous System Toxicity Central nervous system toxicity Unlikely after administration of glycopyrrolate Drug cannot easily cross the blood-brain barrier Toxicity attributed to the anticholinergic May represent uninhibited response to pain as the depressant effects of the anesthetic dissipate 195
196 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Undesirable Side Effects – Central Nervous System Toxicity Central anticholinergic syndrome presumably reflects blockade of muscarinic cholinergic receptors in the central nervous system Physostigmine Up to 2 mg IV For life-threatening anticholinergic toxicity administer 1 mg/min specific treatment of the central nervous system toxicity caused by scopolamine or atropine 196
197 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Undesirable Side Effects – Central Nervous System Toxicity Neostigmine and pyridostigmine Not effective anticholinesterase antidotes Quaternary ammonium structure prevents these drugs from easily entering the central nervous system 197
198 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Tachycardia Scopolamine and glycopyrrolate – have minimal cardio-accelerator effects More logical selections than atropine when Increased heart rate would be undesirable Patients with mitral stenosis and atrial fibrillation 198
199 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ANTICHOLINERGICS Tachycardia Most likely cardiac response after the intramuscular administration of Atropine Glycopyrrolate Scopolamine Slowing of the heart rate Reflecting weak cholinergic agonist effect of these drugs 199
200 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication H2 ANTAGONISTS H2 antagonists Counter ability of histamine to induce ecretion of gastric fluid with high concentration of hydrogen ions Offer a pharmacologic approach – increasing gastric fluid pH before induction of anesthesia Routine prophylactic use Not recommended 200
201 : 201
202 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication H2 ANTAGONISTS Inclusion of an H2 antagonist in the pharmacologic premedication May be a consideration in patients thought to be at increased risk for pulmonary aspiration Parturients Morbid obesity Symptoms of esophageal reflux Anticipated difficult airway management Parturients - About to bring forth young; being in labor 202
203 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication H2 ANTAGONISTS Objection to the routine inclusion of H2 antagonists in the preoperative medication Concept that therapies should be individualized Tailored to fit specific patients Their diseases Particular preoperative circumstances 203
204 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication H2 ANTAGONISTS Incidence of pulmonary aspiration and serious morbidity Sufficiently low in patients undergoing elective surgery Cost of preventing one serious complication of pulmonary aspiration by routine use of prophylactic medications H2 antagonists Very high 204
205 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication H2 ANTAGONISTS These drugs are not 100% effective Inherent failure rate H2 antagonists Will not alter the pH of gastric fluid present before administration Will not facilitate gastric emptying 205
206 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication H2 ANTAGONISTS Under no circumstances preoperative medication with H2 antagonists Substituted for an anesthetic technique including placement of a cuffed tracheal tube Maintenance of consciousness to protect the lungs from inhalation of gastric fluid 206
207 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ACID SUPPRESSION Antacids administered 15 to 30 minutes before induction of anesthesia Nearly 100% effective in increasing gastric fluid pH to greater than 2.5 Efficacy of antacids Dependent – to some extent Patient movement Facilitate complete mixing with gastric fluid 207
208 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ACID SUPPRESSION Nonparticulate antacids – sodium citrate Effectively increase gastric fluid pH to greater than 2.5 Do not produce significant pulmonary dysfunction Should inhalation of fluid containing antacids occur 208
209 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ACID SUPPRESSION Contrast to H2 antagonists Administration of antacids Effective in increasing pH of gastric fluid Present in stomach at time of administration Desirable effect Associated with increased gastric fluid volume Does not occur with H2 antagonists 209
210 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ACID SUPPRESSION Withholding antacids because of concern for increasing gastric fluid volume Not warranted Routine inclusion of antacids in pharmacologic premedication Not recommended 210
211 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ACID SUPPRESSION Antacids are more appropriately administered to selected patients Judged by anesthesiologist to be at increased risk for pulmonary aspiration Intravenous administration of a proton pump inhibitor Achieve acid suppression within hours 211
212 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication ACID SUPPRESSION Intravenous formulations in the United States include Esomeprazole - Nexium Lansoprazole – Prevacid Pantoprazole – Protonix 212
213 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Gastrointestinal prokinetics Metoclopramide Cisapride Considered as part of the pharmacologic premedication in selected patients Ability of drugs to stimulate gastric emptying 213
214 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Antiemetic effect of these drugs Not a consistent observation Antibiotic erythromycin Promotes gastric emptying Advocated as pharmacologic method Decreases the risk for aspiration before emergency anesthesia and surgery 214
215 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Metoclopramide Metoclopramide speeds gastric emptying selectively increasing Motility of the upper gastrointestinal tract Relaxing the pyloric sphincter Onset of metoclopramide’s effect 30 to 60 minutes after oral administration 1 to 3 minutes after intravenous injection 215
216 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Metoclopramide May be useful in pharmacologic preoperative medication Decrease gastric fluid volume in at-risk patients Diabetics with gastroparesis Parturients Patients who have recently ingested solids Require emergency surgery for disease unrelated to gastrointestinal tract Anticipated difficult airway management 216
217 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Metoclopramide Metoclopramide does not guarantee gastric emptying Beneficial effects offset by Concomitant or Prior administration of Anticholinergics Opioids Antacids 217
218 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Metoclopramide Ability of metoclopramide to increase lower esophageal sphincter tone Negated by inclusion of atropine in preoperative medication Metoclopramide does not predictably alter gastric fluid pH 218
219 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Metoclopramide Side effects include: Abdominal cramping if rapidly administered intravenously Neurologic dysfunction reflecting Passage into central nervous system Production of dopamine receptor blockade 219
220 : PREOPERATIVE EVALUATION AND MEDICATION Drugs Administered for Pharmacologic Premedication GASTROINTESTINAL PROKINETICS Metoclopramide Administration of metoclopramide in the presence of Known or suspected gastrointestinal obstruction Not recommended 220
221 : PREOPERATIVE EVALUATION AND MEDICATION Premedication for Outpatients Administering pharmacologic preoperative medication to outpatients Avoid – Introduction of persistent drug effects that Delay emergence from anesthesia Prevent early discharge (nausea and vomiting) After elective and usually minor surgery 221
222 : PREOPERATIVE EVALUATIONAND MEDICATION PREOPERATIVE MEDICATION Fasting before Elective Surgery Suggestions for Preoperative Medication 222
223 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Fasting before elective surgery – “NPO after midnight” Based on historical presumption Absence of intake of solids and fluids Minimizes gastric fluid volume at time of induction of anesthesia Decrease the risk for pulmonary aspiration of gastric contents Especially in vulnerable patients 223
224 : 224
225 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Complete gastric emptying can never be guaranteed Regardless of duration of fasting Solid food passes through the stomach Variable and unpredictable rates Up to 12 hours Especially if a high fat content is present 225
226 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Clear liquids 50% emptying time of just 12 to 20 minutes Illogical to have a single guideline for solid food and clear liquid ingestion before induction of anesthesia for elective operations 226
227 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Fears that ingestion of clear fluids 2 hours preceding induction Increase gastric fluid volume at time of induction Unfounded 2 hours elapsed after ingestion of clear liquids Endogenous gastric fluid secretion Principal determinant of volume and pH of gastric fluid Longer fluid fast Does not improve gastric environment 227
228 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Preoperative anxiety Not been documented to slow gastric emptying Opioids may slow gastric emptying Not been verified that drug-induced effect influences the rate of emptying of clear liquids 228
229 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Recommendations for fasting before elective surgery Modified from previously strict adherence to prohibition against the intake of solids and liquids for several hours before induction of anesthesia for elective surgery 229
230 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Clear liquids Water Fruit juices without pulp Carbonated beverages Clear tea Black coffee Permitted up to 2 hours before induction of anesthesia for elective operations 230
231 : 231 These recommendations apply to healthy patients undergoing elective operations exclusive of parturients. Following these recommendations does not guarantee that gastric emptying has occurred. Adapted from Warner MA, Caplan RA, Epstein BS, et al. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: Application to healthy patients undergoing elective procedures. Anesthesiology 1999;90:896-905.
232 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Longer fasting interval is required for milk and solid foods. 232
233 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Acceptable to administer drugs Pharmacologic premedication Medications being taken by the patient preoperatively With up to 150 mL of water in the hour preceding induction of anesthesia 233
234 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery Preoperative oral nutrition with a special carbohydrate rich beverage Does not appear to increase gastric fluid volume or acidity Existing guidelines Do not clarify management of patients who have known gastric emptying problems 234
235 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery PROPHYLAXIS FOR ASPIRATION Aspiration Estimated to occur in 1 in 3200 operations Relatively uncommon event When anesthesia-related aspiration occurs and leads to acute lung injury Complication is associated with 10% to 30% of anesthesia-related deaths 235
236 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery PROPHYLAXIS FOR ASPIRATION Administration of proton pump inhibitors Suppresses acid secretion in response to all primary stimulants Histamine Gastrin Acetylcholine Inhibitors are not associated with tolerance 236
237 : PREOPERATIVE EVALUATION AND MEDICATION Fasting before Elective Surgery PROPHYLAXIS FOR ASPIRATION Omeprazole, 20 mg administered orally Evening before, or 2 hours before surgery Equivalent to sodium citrate Suppression of acid within 20 minutes Achieved by administering Pantoprazole, 40 mg intravenously 237
238 : PREOPERATIVE EVALUATION AND MEDICATION Suggestions for Preoperative Medication Best drug or drug combination to achieve the desired goals of pharmacologic premedication is not known and is often influenced by the individual anesthesiologist’s previous experience 238
239 : 239

 

Add as Friend By : Carl
Added On : 1 Years ago.
What is involved in preoperative evaluation of a patient to ensure the best anesthetic care for the    more
Views 547 | Favourite 0 | Total Upload :22

Embed Code:

Flag as inappropriate


Related  Most Viewed



Free Powerpoint Templates



 



Medical PowerPoint Templates | Powerpoint Templates | Tags | Contact | About Us | Privacy | FAQ | Blog

© Slideworld