________ Original Contributions General versus Epidural Anesthesia for FemoralPopliteal Bypass Surgery Michael C. Damask, MD,* Charles Weissman, MD,t George Todd, MD:j: Departments of Anesthesiology, Surgery, and Medicine, College of Physicians and Surgeons, Columbia University, New York, NY.
*Assistant
Professor of Anesthesiology
t Assistant Professor of Anesthesiology and Medicine :j:Associate Professor of Clinical Surgery Address reprint requests to Dr. Weissman at the Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA. Presented in part at the 1986 Annual Meeting of the International Anesthesia Research Society, Las Vegas, Nevada, March. Received for publication January 10, 1989; revised manuscript accepted for publication July 31,1989. © 1990 Butterworth Publishers
This study examines whether epidural anesthesia is more effective than general anesthesia using an inhalation agent in controlling cardiovascular responses during femoral-popliteal bypass surgery. Nineteen patients were randomized into two groups: general anesthesia (n = 10) and epidural anesthesia (n = 9). The patients who underwent general anesthesia received sodium pentothal and succinylcholine for induction of anesthesia and 60% N 20, 40% O2 , and 1 % to 1.5% isojlurane for maintenance. Fifteen minutes before extubation, the patients received morphine sulfate 0.05 mglkg intravenously (IV). The group that underwent epidural anesthesia received anesthesia to T-IO (through a catheter placed in the L4-5 interspace using 3% 2-chloroprocaine). Thirty minutes after the last dose, 0.05 mglkg IV was administered. Hemodynamic variables were recorded at selected intervals during the operation and for 60 minutes in the recovery room. In the general anesthesia group, mean arterial pressure (MAP) and rate pressure product (RPP) significantly decreased (p < 0.05) during the operation as compared with preoperative values. Following intubation and skin incision, 5 minutes after extubation, and after 60 minutes in the recovery room, MAP, heart rate (HR), and RPP were significantly greater (p < 0.05) as compared with intraoperative periods. In the epidural anesthesia group, there were clinically important decreases in MAP and RPP after reaching T -10 and skin incision. The general anesthesia patients showed higher MAP, HR, and RPP 5 minutes after extubation and after 60 minutes in the recovery room. Epidural anesthesia patients showed stable hemodynamic patterns throughout the study. This study demonstrates that epidural anesthesia allows for a more stable intraoperative and postoperative course as compared to the general anesthesia technique used, especially at the end of surgery and in the recovery room.
Keywords: Epidural anesthesia; peripheral vascular surgery; general anesthesia.
J.
Clin. Anesth., vol. 2, March/April 1990
71
Original Contributions
Introduction Patients with peripheral vascular disease of the lower extremities often have coexisting coronary artery disease and cerebrovascular disease. l This fact is emphasized by Hertzer et al.,2 who found that of 500 patients scheduled for vascular surgery with normal electrocardiograms (EKGs) and no history of myocardial infarction, 37% had a 70% stenosis of one or more coronary arteries on coronary angiography. Unstable HR and blood pressure (BP) can so exacerbate a patient's underlying cardiovascular disease that it may become problematic. This situation can, in certain cases, lead to myocardial infarction or cerebrovascular accident in the perioperative period. 3 A major goal of anesthetic management in such patients is to control the circulatory stresses of surgery and anesthesia to prevent untoward cardiovascular complications. This study examines whether epidural anesthesia is more effective than general anesthesia using an inhalation agent in tempering the cardiovascular response during femoral-popliteal bypass surgery. Studies in healthy patients undergoing nonvascular general surgical procedures have demonstrated that epidural anesthesia can reduce the hormonal responses to surgery by blocking nocioceptive stimuli to the hypothalamus. It should therefore
Table 1.
be expected that epidural anesthesia leads to reduced cardiovascular responses when compared to general anesthesia using an inhalation agent. 4 - 8 The purpose of this study was to determine the differences in hemodynamics between epidural and general anesthesia in patients undergoing femoral-popliteal bypass surgery.
Materials and Methods This study was approved by the Institutional Review Board of Columbia-Presbyterian Medical Center. Written informed consent was obtained from 19 patients requiring femoral-popliteal bypass surgery (Table 1). All patients were premedicated with morphine sulfate 0.1 mg/kg intramuscularly (1M) 90 minutes before surgery. The radial artery was cannulated with a 20-gauge catheter, and a thermodilution flow-directed balloon pulmonary artery catheter (Quadruple Lumen Thermo-dilution Model 93A131-7.5F, Baxter-Edwards Critical Care, Santa Ana, CA) was percutaneously introduced into the pulmonary artery through the right internal jugular vein. Patients were randomized into two groups: general anesthesia (n = 10) and epidural anesthesia (n = 9). Seven epidural anesthesia patients and two general
Patient Characteristics
Patients Age (yr) Weight (kg) Body surface area
Group 1: General Anesthesia
Group 2: Epidural Anesthesia
8 males; 2 females
6 males; 3 females
64
10 78 ± 14 1.7 ± 0.3 ±
71 ± 10 77 ± 14 1.8 ± 0.2
(m2)
Preop SP (mmHg) DP (mmHg) HR (beats/min) OR time (h) FA cross-clamp (min) Fluids (L) Coexisting disease Medications
Drugs in OR
134 ± 19 77 ± 4 74 ± 7.4 4.8 ± 1.4 50 ± 19 4.0 ± I DM (4); Hyp (3); CAD (2); sip MI < 24 mo (2); COPD (2); CHF (1) NPH (2); oral hypoglycemics (2); furosemide (1); nadolol (1); chlorpropamide (1); metoprolol (1); propranolol (1); clonidine (1); captopril (1) Diazepam (2); nitroglycerin (2); phenylephrine
137 ± 22 82 ± 5.0 75 ± 14
3.6 ± 1 38 ± 17 3.6 ± 0.7 DM (2); Hyp (3); CAD (3); sip MI < 24 mo (2); COPD (2); CVD (1) NPH (1); oral hypoglycemics (1); metoprolol (5); isosorbide (2); diltiazem (1); nifedipine (1); hydrochlorothiazide (2) Diazepam (7); phenylephrine (3)
(1) All values are mean ± SD. SP = systolic blood pressure; DP = diastolic blood pressure; HR = heart rate; OR = operating room; FA = femoral artery; DM = diabetes mellitus; Hyp = hypertension; CAD = coronary artery disease; sip MI = status post-myocardial infarction; COPD = chronic obstructive pulmonary disease; CHF = congestive heart failure; CVD = cerebrovascular disease.
72
J.
Clin. Anesth., vol. 2, March/April 1990
General versus epidural nne.rthniu: Damask et al.
anesthesia patients received 2.5 mg diazepam IV before placement of indwelling catheters. Patients assigned to general anesthesia received metocurine iodide (2 mg IV), thiopental (4 mg/kg IV), and lidoCaine (1.0 mg/kg IV) for induction and succinylcholine (1.5 mg/kg IV) for intubation. Anesthesia was maintained with 60% N20, 40% 02, and 1% to 1.5% isoflurane using mechanical ventilation. Arterial blood gases were maintained at pH 7.35 to 7.45; arterial carbon dioxide (PaCO,) at 35 to 45 mmHg; and arterial oxygen (PaO,) at 150 mmHg or greater. The aim in the general anesthesia group was to maintain BP within 20% of baseline. Thirty minutes before extubation, the patients received morphine sulfate 0.05 mg/kg IV. The epidural anesthesia group received continuous epidural anesthesia extending to T- 10 through a catheter placed at the L4-5 interspace using 3% 2-chloroprocaine with 3 L/min supplemental nasal oxygen. Additional 2-chloroprocaine was administered every 30 minutes to ensure a constant level of anesthesia (average total dose 62 ml per patient). P-chloroprocaine was discontinued 30 minutes before the end of surgery, and morphine sulfate 0.05 mg/kg IV was administered. The epidural catheter was removed before the patient’s discharge from the recovery room. MAP, EKG, HR, pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), core body temperature, and cardiac output (CO) [thermodilution technique in duplicate with cold 5% dextrose in water (CO computer Model 7823 lC, HewlettPackard, Andover, MA)] were recorded at the following intervals:
chronic obstructive pulmonary disease was similar in both groups (Table I), as were the operation characteristics, preoperative systolic and diastolic BPS, and pulse. In the general anesthesia group, two patients required intraoperative nitroglycerin for BP control, and one patient received phenylephrine to stabilize BP. In the epidural anesthesia group, three patients required intraoperative phenylephrine at the beginning of the anesthetic to stabilize BP. No patients in either group required any supplemental analgesia in the recovery room.
1. 5 minutes after insertion of indwelling catheters 2. 5 minutes after intubation or after reaching T-10 level 3. 5 minutes after skin incision 4. 15 minutes after femoral artery clamping 5. 15 minutes after femoral artery unclamping 6. 5 minutes after extubation or last epidural dose 7. 60 minutes in recovery room An EKG was performed on all patients in the recovery room. The cardiac index (CI) and RPP were calculated using standard formulas9 Intergroup and intragroup differences were compared using an unpaired t-test and repeated measures analysis of variance with Tukey post-hoc test, respectively; p < 0.05 was considered statistically significant.
Unlike the epidural anesthesia patients, the general anesthesia patients had greater increases in RPP after insertion of indwelling catheters. The general anesthesia patients showed higher MAP, HR, and RPP 5 minutes after extubation and 60 minutes after arrival in the recovery room (Figure 1). The epidural anesthesia patients showed stable hemodynamic patterns throughout the study. There were some significant differences in CI, PCWP, and CVP between the two groups at various points throughout the study. These were especially evident during surgery, when CVP and PCWP were higher and CI lower in the general anesthesia group. No patient had perioperative ischemic EKG changes or dysrhythmias. All patients maintained body temperatures of 35°C to 36°C throughout the operation.
Results
Discussion
The frequency of coronary artery disease, cerebral vascular disease, diabetes mellitus, hypertension, and
In this study, epidural anesthesia provided cardiovascular conditions that were more stable than those
Intragroup Comparisons In the general anesthesia group, MAP and RPP decreased significantly (p < 0.05) following intubation and skin incision. Five minutes after extubation and 60 minutes after arrival in the recovery room, MAP, HR, and RPP were significantly greater (p < 0.05) as compared with the intraoperative periods (Figure 1). CI decreased significantly after intubation and skin incision but recovered to preoperative values by the end of surgery and in the recovery room. In the epidural anesthesia group, MAP and RPP decreased after reaching T- 10 and skin incision. These parameters changed little throughout surgery. In the recovery room, HR, CI, and RPP were significantly greater than during the last dose of local anesthetic.
Intergroup Comparisons
J. Clin. Anesth., vol. 2, March/April
1990
73
Original Contributions
I
2
3
4 ~--...-a M
5 6 7 GA (10 -c SD) EP ( 9 2 SD)
Figure 1. Hemodynamic variables at various points during perioperative period: 1 to 5 minutes after insertion of indwelling catheters; 2 to 5 minutes after incubation or after reaching T-10 level; 3 to 5 minutes after skin incision; 4 to 15 minutes after femoral artery (FA) clamping; 5 to 15 minutes after FA unclamping; 6 to 15 minutes after extnbation or last epidural dose; 7 to 60 minutes in recovet_y room. All values are mean t SD. General US epidural dlfferences: *p < 0.05; **p < 0.01; ***p < 0.001. lntrdgroup differences: different from 1: *p < 0.05; ++p < 0.001; dif’ferent from 5: ‘p < 0.05; “p < 0.01; “‘p < 0.001: different from 6: *p < 0.05; *;$I < 0.01.
74
J. Clin. Anesth.,
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1990
encountered during general anesthesia using a specific inhalation technique. This finding was especially evident at the beginning and end of surgery. ‘l‘he lower HK, MAP, and RPP after insertion of the indwelling catheters were probably due to the administration of diazepam in most of the epidural anesthesia patients upon arrival in the operating room. ‘l-he general anesthesia patients had substantial increases in CI, MAP, HR, and RPP immediately following extubation, while the epidural anesthesia group showed no change in any of these variables. This observation demonstrates that emergence from general anesthesia can be very stressful lo the patient. Pain, shivering, hypoxemia, hypercarbia, and reaction to the endotracheal tube represent a critical period during which cardiovascular instability can occur.“’ ‘I‘his situation is avoided with epidural anesthesia. Many investigations have focused on the hemodynamic problems of anesthetic induction and intubation rather than on emergence from general anesthesia. During the induction of general anesthesia with direct larvngoscopy for endotracheal intubation, great stress can be placed on the cardiovascular system.“.12 Increases in the catecholamine and cortisol levels in the blood have been directly implicated as the cause of this stress response during anesthetic induction and surgery. ‘.u ‘This hormonal stress rcsponse is translated clinically into increases in the patient’s HK, systemic vascular resistance, and increased cardiac contractility. ‘I-his fact, coupled with stress created by the surgical procedures, may lead to cardiovascular complications during and after the operation. Patients who are undergoing femoral-popliteal bypass surgerv and have inherent cardiovascular disease are at a greater risk for developing cardiovascular conplications than those in the general l>atient population. An increase in KPP, especially when due to a major increase in HK, has been correlated with perioperative myocardial ischemia.“-“’ Although these observations were made in patients undergoing coronarv aI-tery bypass surgery, similar manifestations of coronary artery disease are seen in patients undergoing femoral-popliteal bypass surgerv. As this stud! emphasizes, these detrimental conditions are seen not only during intubation. a relatively controlled period, but also during extubation, a period during which adverse hemodynamic factors are operative.‘; It is inportant to note that in the present study, most of the increase in RPP was due Taoincreases in systolic HP rather than tachycardia. Other differences in hemcidynamics between the two groups were the higher PCWP and CVP and the lower (3 during surgery ill the general anesthesia group. This difference could be due to positive pressure ventilation increasing in-
General versus
trathoracic pressure and/or epidural anesthesia, causing vasodilation as a consequence of sympathetic blockade. This finding is important in patients who are hypovolemic and in those who have right heart dysfunction and require adequate right ventricular filling. The main Iinding of this study is the less hemodynamically stressful nature of the epidural anesthetic. This finding is due mainly to the avoidance of intubation and extubation, which are the points of maximal differences between the two groups. Another factor contributing to these differences may be the attenuated hormonal responses seen during epidural anesthesia. Many studies have shown that epidural anesthesia can reduce the afferent impulses entering the central nervous system, thus tempering the release of catecholamines from the peripheral sympathetic nerves.“m7 The effects of- epidural anesthesia on the hemodynamic, hormonal, and biochemical alterations seen during surgery also have been reviewed.lH.lg In conclusion, this study demonstrates that epidural anesthesia allows for a more stable intraoperative and postoperative course as compared with the general anesthesia technique used, especially at the end of surgery and in the recovery room, where cardiovascular instability may be encountered. Further investigations into the stressful characteristics of the immediate postoperative period, and the use of specific anesthetic techniques to control this stress, are needed. This suggestion is especially important given reports that up to 42% of patients with coronary artery disease experience ischemia during surgery.3,‘5,“’ ‘I‘hese studies could include the use of beta-adrenergic antagonists such as esmolol” or 1abatoloP or the use of lidocaine during intubation or extubation. The hemodynamic consequences of a nitrous oxide-narcotic technique also should be explored.
References 1. Sabawala PB, Strong MJ, Keats AS: Surgery of the aorta and its branches. Anesthesiology 1970;33:229-56. 2. Hertzer NR, Beven EC, Young JR, et al: Coronary artery disease in peripheral vascular patients. Classification of 1000 angiograms and results of surgical management. Ann Surg 1984;199:223-39. 3. Kotter GS, Kotrly KJ, Kalbfleisch JH, et al: Myocardial ischemia during cardiovascular surgery as detected by an S-T segment trend monitoring system.j Cardiothoruc Annth 1987; 1: 190-9. 4. Wilmore DW, Long JM, Mason AD, Pruit BA: Stress in surgical patients as neurophysiologic reflex response. Surg Gynecol Obstet 1976;142:257-69.
epidurul anesthesia: Damask et al.
5. Lush D, Thorpe JN, Richardson DJ, Bower DJ: The effect of epidural analgesia on the adrenocortical response to surgery. Br J Anaesth 1972;44: 1169-72. 6. Cosgrove DO, Jenkins JS: The effects of epidural anesthesia on the pituitary-adrenal response to surgery. Clin Sci Mol Med 1974;46:403-7. 7. Enquist A, Brandt MR, Fernandes A, Kehlet H: The blocking effect of epidural analgesia on the adrenocortical and hyperglycemic responses to surgery. Acta Anaesth Sand 1977;21:330-55. 8. Kehlet H: Influence of epidural analgesia on the enActa Anaesth docrine-metabolic response to surgery. &and 1978;70 (Suppl):39-42. 9. Kaplan JA: Hemodynamic monitoring. In Kaplan JA, ed. Cardiac Anesthesia. New York: Grunt: and Stratton, 1979: 95. 10. Rodriguez J, Weissman C, Damask MC, et al: Morphine and postoperative rewarming in critically ill patients. Circulation 1983;68: 1238-46. 11. Price HL, Linde HW, Jones RE, et al: Sympatho-adrenal responses to general anesthesia in man and their relation to hemodynamics.Anesthesiology 1959;20:563-75. responses 12. Millar RA, Morris ME: Sympatho-adrenal during general anesthesia in dog and man. Can Anaesth Sot J 1961;8:356-86. 13. Hume DM, Bell CC, Bartter F: Direct measurement of adrenal secretion during operative trauma and convalescence. Surgery 1962;52: 174-87. 14. Cokkinos DV, Voridis EM: Constancy of rate pressure product in pacing induced angina pectoris. Br Heart J 1976;38:39-42. 15. Slogoff S, Keats AS: Does perioperative myocardial ischemia lead to postoperative myocardial infarction? Ane.&esiology 1985;62: 107- 14. 16. Slogoff‘ S, Keats AS: Further observations on perioperative myocardial ischemia. Anesthesiolqgy 1986;65:53942. 17. McIntyre RW, Hart A: Perioperative ischemia and infarction: non-cardiac surgery. Anesth Clin NA 1988;6: 527-43. 18. Weissman C, Hollinger I: Modifying systemic responses with anesthetic techniques. Anesth Clin NA 1988;6:22137. 19. Pasternack PF, Imparato AM, Baumann FC, et al: The hemodynamics of beta-blockade in patients undergoing abdominal aortic aneurysm repair. Circzllation 1987; 76: (Suppl 3) l-7. 20. Coriat P, Harari A, Daloz M, et al: Clinical predictors of intraoperative myocardial ischemia in patients with coronary artery disease undergoing non-cardiac surgery. Acta Anaesth &and 1982;26:287-90. 21. Cirard D, Shalmar BJ, Thys DM, et al: Safety and efficacy of esmolol during myocardial revascularization. Anesthesiology 1986;65: 157-62. 22. Stone JC, Foex P, Sear J, et al: Myocardial ischemia in untreated hypertensive patients: effect of a single small oral dose of a beta-blocker. Anesthesiology 1988;68:495503.
J. Clin. Anesth.,
vol. 2, March/April
1990
75
*Assistant
Professor of Anesthesiology
t Assistant Professor of Anesthesiology and Medicine :j:Associate Professor of Clinical Surgery Address reprint requests to Dr. Weissman at the Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA. Presented in part at the 1986 Annual Meeting of the International Anesthesia Research Society, Las Vegas, Nevada, March. Received for publication January 10, 1989; revised manuscript accepted for publication July 31,1989. © 1990 Butterworth Publishers
This study examines whether epidural anesthesia is more effective than general anesthesia using an inhalation agent in controlling cardiovascular responses during femoral-popliteal bypass surgery. Nineteen patients were randomized into two groups: general anesthesia (n = 10) and epidural anesthesia (n = 9). The patients who underwent general anesthesia received sodium pentothal and succinylcholine for induction of anesthesia and 60% N 20, 40% O2 , and 1 % to 1.5% isojlurane for maintenance. Fifteen minutes before extubation, the patients received morphine sulfate 0.05 mglkg intravenously (IV). The group that underwent epidural anesthesia received anesthesia to T-IO (through a catheter placed in the L4-5 interspace using 3% 2-chloroprocaine). Thirty minutes after the last dose, 0.05 mglkg IV was administered. Hemodynamic variables were recorded at selected intervals during the operation and for 60 minutes in the recovery room. In the general anesthesia group, mean arterial pressure (MAP) and rate pressure product (RPP) significantly decreased (p < 0.05) during the operation as compared with preoperative values. Following intubation and skin incision, 5 minutes after extubation, and after 60 minutes in the recovery room, MAP, heart rate (HR), and RPP were significantly greater (p < 0.05) as compared with intraoperative periods. In the epidural anesthesia group, there were clinically important decreases in MAP and RPP after reaching T -10 and skin incision. The general anesthesia patients showed higher MAP, HR, and RPP 5 minutes after extubation and after 60 minutes in the recovery room. Epidural anesthesia patients showed stable hemodynamic patterns throughout the study. This study demonstrates that epidural anesthesia allows for a more stable intraoperative and postoperative course as compared to the general anesthesia technique used, especially at the end of surgery and in the recovery room.
Keywords: Epidural anesthesia; peripheral vascular surgery; general anesthesia.
J.
Clin. Anesth., vol. 2, March/April 1990
71
Original Contributions
Introduction Patients with peripheral vascular disease of the lower extremities often have coexisting coronary artery disease and cerebrovascular disease. l This fact is emphasized by Hertzer et al.,2 who found that of 500 patients scheduled for vascular surgery with normal electrocardiograms (EKGs) and no history of myocardial infarction, 37% had a 70% stenosis of one or more coronary arteries on coronary angiography. Unstable HR and blood pressure (BP) can so exacerbate a patient's underlying cardiovascular disease that it may become problematic. This situation can, in certain cases, lead to myocardial infarction or cerebrovascular accident in the perioperative period. 3 A major goal of anesthetic management in such patients is to control the circulatory stresses of surgery and anesthesia to prevent untoward cardiovascular complications. This study examines whether epidural anesthesia is more effective than general anesthesia using an inhalation agent in tempering the cardiovascular response during femoral-popliteal bypass surgery. Studies in healthy patients undergoing nonvascular general surgical procedures have demonstrated that epidural anesthesia can reduce the hormonal responses to surgery by blocking nocioceptive stimuli to the hypothalamus. It should therefore
Table 1.
be expected that epidural anesthesia leads to reduced cardiovascular responses when compared to general anesthesia using an inhalation agent. 4 - 8 The purpose of this study was to determine the differences in hemodynamics between epidural and general anesthesia in patients undergoing femoral-popliteal bypass surgery.
Materials and Methods This study was approved by the Institutional Review Board of Columbia-Presbyterian Medical Center. Written informed consent was obtained from 19 patients requiring femoral-popliteal bypass surgery (Table 1). All patients were premedicated with morphine sulfate 0.1 mg/kg intramuscularly (1M) 90 minutes before surgery. The radial artery was cannulated with a 20-gauge catheter, and a thermodilution flow-directed balloon pulmonary artery catheter (Quadruple Lumen Thermo-dilution Model 93A131-7.5F, Baxter-Edwards Critical Care, Santa Ana, CA) was percutaneously introduced into the pulmonary artery through the right internal jugular vein. Patients were randomized into two groups: general anesthesia (n = 10) and epidural anesthesia (n = 9). Seven epidural anesthesia patients and two general
Patient Characteristics
Patients Age (yr) Weight (kg) Body surface area
Group 1: General Anesthesia
Group 2: Epidural Anesthesia
8 males; 2 females
6 males; 3 females
64
10 78 ± 14 1.7 ± 0.3 ±
71 ± 10 77 ± 14 1.8 ± 0.2
(m2)
Preop SP (mmHg) DP (mmHg) HR (beats/min) OR time (h) FA cross-clamp (min) Fluids (L) Coexisting disease Medications
Drugs in OR
134 ± 19 77 ± 4 74 ± 7.4 4.8 ± 1.4 50 ± 19 4.0 ± I DM (4); Hyp (3); CAD (2); sip MI < 24 mo (2); COPD (2); CHF (1) NPH (2); oral hypoglycemics (2); furosemide (1); nadolol (1); chlorpropamide (1); metoprolol (1); propranolol (1); clonidine (1); captopril (1) Diazepam (2); nitroglycerin (2); phenylephrine
137 ± 22 82 ± 5.0 75 ± 14
3.6 ± 1 38 ± 17 3.6 ± 0.7 DM (2); Hyp (3); CAD (3); sip MI < 24 mo (2); COPD (2); CVD (1) NPH (1); oral hypoglycemics (1); metoprolol (5); isosorbide (2); diltiazem (1); nifedipine (1); hydrochlorothiazide (2) Diazepam (7); phenylephrine (3)
(1) All values are mean ± SD. SP = systolic blood pressure; DP = diastolic blood pressure; HR = heart rate; OR = operating room; FA = femoral artery; DM = diabetes mellitus; Hyp = hypertension; CAD = coronary artery disease; sip MI = status post-myocardial infarction; COPD = chronic obstructive pulmonary disease; CHF = congestive heart failure; CVD = cerebrovascular disease.
72
J.
Clin. Anesth., vol. 2, March/April 1990
General versus epidural nne.rthniu: Damask et al.
anesthesia patients received 2.5 mg diazepam IV before placement of indwelling catheters. Patients assigned to general anesthesia received metocurine iodide (2 mg IV), thiopental (4 mg/kg IV), and lidoCaine (1.0 mg/kg IV) for induction and succinylcholine (1.5 mg/kg IV) for intubation. Anesthesia was maintained with 60% N20, 40% 02, and 1% to 1.5% isoflurane using mechanical ventilation. Arterial blood gases were maintained at pH 7.35 to 7.45; arterial carbon dioxide (PaCO,) at 35 to 45 mmHg; and arterial oxygen (PaO,) at 150 mmHg or greater. The aim in the general anesthesia group was to maintain BP within 20% of baseline. Thirty minutes before extubation, the patients received morphine sulfate 0.05 mg/kg IV. The epidural anesthesia group received continuous epidural anesthesia extending to T- 10 through a catheter placed at the L4-5 interspace using 3% 2-chloroprocaine with 3 L/min supplemental nasal oxygen. Additional 2-chloroprocaine was administered every 30 minutes to ensure a constant level of anesthesia (average total dose 62 ml per patient). P-chloroprocaine was discontinued 30 minutes before the end of surgery, and morphine sulfate 0.05 mg/kg IV was administered. The epidural catheter was removed before the patient’s discharge from the recovery room. MAP, EKG, HR, pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), core body temperature, and cardiac output (CO) [thermodilution technique in duplicate with cold 5% dextrose in water (CO computer Model 7823 lC, HewlettPackard, Andover, MA)] were recorded at the following intervals:
chronic obstructive pulmonary disease was similar in both groups (Table I), as were the operation characteristics, preoperative systolic and diastolic BPS, and pulse. In the general anesthesia group, two patients required intraoperative nitroglycerin for BP control, and one patient received phenylephrine to stabilize BP. In the epidural anesthesia group, three patients required intraoperative phenylephrine at the beginning of the anesthetic to stabilize BP. No patients in either group required any supplemental analgesia in the recovery room.
1. 5 minutes after insertion of indwelling catheters 2. 5 minutes after intubation or after reaching T-10 level 3. 5 minutes after skin incision 4. 15 minutes after femoral artery clamping 5. 15 minutes after femoral artery unclamping 6. 5 minutes after extubation or last epidural dose 7. 60 minutes in recovery room An EKG was performed on all patients in the recovery room. The cardiac index (CI) and RPP were calculated using standard formulas9 Intergroup and intragroup differences were compared using an unpaired t-test and repeated measures analysis of variance with Tukey post-hoc test, respectively; p < 0.05 was considered statistically significant.
Unlike the epidural anesthesia patients, the general anesthesia patients had greater increases in RPP after insertion of indwelling catheters. The general anesthesia patients showed higher MAP, HR, and RPP 5 minutes after extubation and 60 minutes after arrival in the recovery room (Figure 1). The epidural anesthesia patients showed stable hemodynamic patterns throughout the study. There were some significant differences in CI, PCWP, and CVP between the two groups at various points throughout the study. These were especially evident during surgery, when CVP and PCWP were higher and CI lower in the general anesthesia group. No patient had perioperative ischemic EKG changes or dysrhythmias. All patients maintained body temperatures of 35°C to 36°C throughout the operation.
Results
Discussion
The frequency of coronary artery disease, cerebral vascular disease, diabetes mellitus, hypertension, and
In this study, epidural anesthesia provided cardiovascular conditions that were more stable than those
Intragroup Comparisons In the general anesthesia group, MAP and RPP decreased significantly (p < 0.05) following intubation and skin incision. Five minutes after extubation and 60 minutes after arrival in the recovery room, MAP, HR, and RPP were significantly greater (p < 0.05) as compared with the intraoperative periods (Figure 1). CI decreased significantly after intubation and skin incision but recovered to preoperative values by the end of surgery and in the recovery room. In the epidural anesthesia group, MAP and RPP decreased after reaching T- 10 and skin incision. These parameters changed little throughout surgery. In the recovery room, HR, CI, and RPP were significantly greater than during the last dose of local anesthetic.
Intergroup Comparisons
J. Clin. Anesth., vol. 2, March/April
1990
73
Original Contributions
I
2
3
4 ~--...-a M
5 6 7 GA (10 -c SD) EP ( 9 2 SD)
Figure 1. Hemodynamic variables at various points during perioperative period: 1 to 5 minutes after insertion of indwelling catheters; 2 to 5 minutes after incubation or after reaching T-10 level; 3 to 5 minutes after skin incision; 4 to 15 minutes after femoral artery (FA) clamping; 5 to 15 minutes after FA unclamping; 6 to 15 minutes after extnbation or last epidural dose; 7 to 60 minutes in recovet_y room. All values are mean t SD. General US epidural dlfferences: *p < 0.05; **p < 0.01; ***p < 0.001. lntrdgroup differences: different from 1: *p < 0.05; ++p < 0.001; dif’ferent from 5: ‘p < 0.05; “p < 0.01; “‘p < 0.001: different from 6: *p < 0.05; *;$I < 0.01.
74
J. Clin. Anesth.,
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1990
encountered during general anesthesia using a specific inhalation technique. This finding was especially evident at the beginning and end of surgery. ‘l‘he lower HK, MAP, and RPP after insertion of the indwelling catheters were probably due to the administration of diazepam in most of the epidural anesthesia patients upon arrival in the operating room. ‘l-he general anesthesia patients had substantial increases in CI, MAP, HR, and RPP immediately following extubation, while the epidural anesthesia group showed no change in any of these variables. This observation demonstrates that emergence from general anesthesia can be very stressful lo the patient. Pain, shivering, hypoxemia, hypercarbia, and reaction to the endotracheal tube represent a critical period during which cardiovascular instability can occur.“’ ‘I‘his situation is avoided with epidural anesthesia. Many investigations have focused on the hemodynamic problems of anesthetic induction and intubation rather than on emergence from general anesthesia. During the induction of general anesthesia with direct larvngoscopy for endotracheal intubation, great stress can be placed on the cardiovascular system.“.12 Increases in the catecholamine and cortisol levels in the blood have been directly implicated as the cause of this stress response during anesthetic induction and surgery. ‘.u ‘This hormonal stress rcsponse is translated clinically into increases in the patient’s HK, systemic vascular resistance, and increased cardiac contractility. ‘I-his fact, coupled with stress created by the surgical procedures, may lead to cardiovascular complications during and after the operation. Patients who are undergoing femoral-popliteal bypass surgerv and have inherent cardiovascular disease are at a greater risk for developing cardiovascular conplications than those in the general l>atient population. An increase in KPP, especially when due to a major increase in HK, has been correlated with perioperative myocardial ischemia.“-“’ Although these observations were made in patients undergoing coronarv aI-tery bypass surgery, similar manifestations of coronary artery disease are seen in patients undergoing femoral-popliteal bypass surgerv. As this stud! emphasizes, these detrimental conditions are seen not only during intubation. a relatively controlled period, but also during extubation, a period during which adverse hemodynamic factors are operative.‘; It is inportant to note that in the present study, most of the increase in RPP was due Taoincreases in systolic HP rather than tachycardia. Other differences in hemcidynamics between the two groups were the higher PCWP and CVP and the lower (3 during surgery ill the general anesthesia group. This difference could be due to positive pressure ventilation increasing in-
General versus
trathoracic pressure and/or epidural anesthesia, causing vasodilation as a consequence of sympathetic blockade. This finding is important in patients who are hypovolemic and in those who have right heart dysfunction and require adequate right ventricular filling. The main Iinding of this study is the less hemodynamically stressful nature of the epidural anesthetic. This finding is due mainly to the avoidance of intubation and extubation, which are the points of maximal differences between the two groups. Another factor contributing to these differences may be the attenuated hormonal responses seen during epidural anesthesia. Many studies have shown that epidural anesthesia can reduce the afferent impulses entering the central nervous system, thus tempering the release of catecholamines from the peripheral sympathetic nerves.“m7 The effects of- epidural anesthesia on the hemodynamic, hormonal, and biochemical alterations seen during surgery also have been reviewed.lH.lg In conclusion, this study demonstrates that epidural anesthesia allows for a more stable intraoperative and postoperative course as compared with the general anesthesia technique used, especially at the end of surgery and in the recovery room, where cardiovascular instability may be encountered. Further investigations into the stressful characteristics of the immediate postoperative period, and the use of specific anesthetic techniques to control this stress, are needed. This suggestion is especially important given reports that up to 42% of patients with coronary artery disease experience ischemia during surgery.3,‘5,“’ ‘I‘hese studies could include the use of beta-adrenergic antagonists such as esmolol” or 1abatoloP or the use of lidocaine during intubation or extubation. The hemodynamic consequences of a nitrous oxide-narcotic technique also should be explored.
References 1. Sabawala PB, Strong MJ, Keats AS: Surgery of the aorta and its branches. Anesthesiology 1970;33:229-56. 2. Hertzer NR, Beven EC, Young JR, et al: Coronary artery disease in peripheral vascular patients. Classification of 1000 angiograms and results of surgical management. Ann Surg 1984;199:223-39. 3. Kotter GS, Kotrly KJ, Kalbfleisch JH, et al: Myocardial ischemia during cardiovascular surgery as detected by an S-T segment trend monitoring system.j Cardiothoruc Annth 1987; 1: 190-9. 4. Wilmore DW, Long JM, Mason AD, Pruit BA: Stress in surgical patients as neurophysiologic reflex response. Surg Gynecol Obstet 1976;142:257-69.
epidurul anesthesia: Damask et al.
5. Lush D, Thorpe JN, Richardson DJ, Bower DJ: The effect of epidural analgesia on the adrenocortical response to surgery. Br J Anaesth 1972;44: 1169-72. 6. Cosgrove DO, Jenkins JS: The effects of epidural anesthesia on the pituitary-adrenal response to surgery. Clin Sci Mol Med 1974;46:403-7. 7. Enquist A, Brandt MR, Fernandes A, Kehlet H: The blocking effect of epidural analgesia on the adrenocortical and hyperglycemic responses to surgery. Acta Anaesth Sand 1977;21:330-55. 8. Kehlet H: Influence of epidural analgesia on the enActa Anaesth docrine-metabolic response to surgery. &and 1978;70 (Suppl):39-42. 9. Kaplan JA: Hemodynamic monitoring. In Kaplan JA, ed. Cardiac Anesthesia. New York: Grunt: and Stratton, 1979: 95. 10. Rodriguez J, Weissman C, Damask MC, et al: Morphine and postoperative rewarming in critically ill patients. Circulation 1983;68: 1238-46. 11. Price HL, Linde HW, Jones RE, et al: Sympatho-adrenal responses to general anesthesia in man and their relation to hemodynamics.Anesthesiology 1959;20:563-75. responses 12. Millar RA, Morris ME: Sympatho-adrenal during general anesthesia in dog and man. Can Anaesth Sot J 1961;8:356-86. 13. Hume DM, Bell CC, Bartter F: Direct measurement of adrenal secretion during operative trauma and convalescence. Surgery 1962;52: 174-87. 14. Cokkinos DV, Voridis EM: Constancy of rate pressure product in pacing induced angina pectoris. Br Heart J 1976;38:39-42. 15. Slogoff S, Keats AS: Does perioperative myocardial ischemia lead to postoperative myocardial infarction? Ane.&esiology 1985;62: 107- 14. 16. Slogoff‘ S, Keats AS: Further observations on perioperative myocardial ischemia. Anesthesiolqgy 1986;65:53942. 17. McIntyre RW, Hart A: Perioperative ischemia and infarction: non-cardiac surgery. Anesth Clin NA 1988;6: 527-43. 18. Weissman C, Hollinger I: Modifying systemic responses with anesthetic techniques. Anesth Clin NA 1988;6:22137. 19. Pasternack PF, Imparato AM, Baumann FC, et al: The hemodynamics of beta-blockade in patients undergoing abdominal aortic aneurysm repair. Circzllation 1987; 76: (Suppl 3) l-7. 20. Coriat P, Harari A, Daloz M, et al: Clinical predictors of intraoperative myocardial ischemia in patients with coronary artery disease undergoing non-cardiac surgery. Acta Anaesth &and 1982;26:287-90. 21. Cirard D, Shalmar BJ, Thys DM, et al: Safety and efficacy of esmolol during myocardial revascularization. Anesthesiology 1986;65: 157-62. 22. Stone JC, Foex P, Sear J, et al: Myocardial ischemia in untreated hypertensive patients: effect of a single small oral dose of a beta-blocker. Anesthesiology 1988;68:495503.
J. Clin. Anesth.,
vol. 2, March/April
1990
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