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The subtleties of anesthetic technique
Journal of
CardiothoracicAnesthesia VOL 4, NO 3
JUNE 1990
EDITORIAL The Subtleties
of Anesthetic
T
HE FIRST FOUR articles in this issue of the JOURNAL concern themselves with the subtleties of anesthetic technique.lM4 Each of these contributions focuses attention on what, when, and how either the usual premedicants, anesthetics, and anesthetic adjuvants, or one of the new agents (propofol) or infusion approaches (computer-calculated and directed exponentially declining infusion of an opioid or benzodiazepine) is used as part of an anesthetic technique. All of the studies attempt to assess the impact of the particular anesthetic technique in question on hemodynamics and clinical outcome (incidence of myocardial ischemia or infarction, time of recovery, etc). The stated and unstated objectives of the four studies were: 1. to determine if the specific drugs, combinations of drugs, drug sequences, and/or infusion rates or techniques of infusion could optimize hemodynamics and clinical conditions and minimize or eliminate adverse side effects; 2. to judge if the anesthetic technique in question was superior to others using the same or related drugs or administration techniques; 3. to obtain insight as to additional changes that could be made in future studies to further optimize outcome; and 4. to uncover a new principle or fundamental truth. Although these goals are not new, they are noble, especially in the current environment where attempting “to understand a mechanism of action” generally earns more academic credit and is much more likely to be successful in winning a competitive research grant. While it is clear that anesthesiology and anesthesiologists need safer and better anesthetics and simpler, more reliable, less traumatic, and more costJournal of Cardiothoracic Anesthesia, Vol4,
No 3
(June), 1990:
Technique
effective techniques of administering these agents,5S7 it is also clear that as much or more attention needs to be spent improving our understanding of the drugs available today and deciding how we can best optimize their administration. Of course, this can only happen when interested clinician-researchers are willing to design and carefully implement clinical studies that highlight subtleties of anesthetic technique. The enormous impact that a subtle change in anesthetic technique can have on clinical outcome was first brought to my attention after our initial reports on high-dose fentanyl anesthesia and the subsequent attempts of others to repeat our studies.8-‘3 Our first reports did not describe the fact that before induction was begun with fentanyl, 3 mg of d-tubocurarine or 1 mg of pancuronium was administered.8-10 This omission occurred because all patients receiving succinylcholine in our institution were given small doses of these nondepolarizing muscle relaxants to prevent the fasciculations associated with succinylcholine. The practice was so ubiquitous we forgot to mention it in our manuscript. However, this very subtle point was extremely important regarding the incidence and magnitude of fentanyl-induced rigidity. We virtually never experienced rigidity with anesthetic doses of fentanyl in our hospital. Yet others attempting to repeat our studies and not knowing of our practice of administering a small dose of a nondepolarizing muscle relaxant just before induction found high incidences of severe chest wall rigidity. ‘lo* Rigidity after high doses of narcotics is rarely found in anesthetic practice today because clinicians now either administer a small dose of one of the many available nondepolarizing muscle relaxants before induction with a narcotic and paralysis with succinylcholine,3 or coadminister large doses of a nondepolarizing
pp 305-307
305
306
THEODORE H. STANLEY
muscle relaxant with the narcotic.’ The coadministration of a large dose of a nondepolarizing muscle relaxant is also a subtle change from our original description of high-dose fentanyl anesthesia. This subtle change often produced dramatic differences in the hemodynamic profile of highdose fentanyl anesthesia in the early days when a large dose of pancuronium was often used as the muscle relaxant. ‘i Instead of no change or slight reductions in heart rate, arterial blood pressure, and systemic resistance (as was found when succinylcholine was the muscle relaxant), increases in all of these variables were frequently seen, especially after endotracheal intubation and sternotomy. “Jo Thomson et ali4 even reported a higher incidence of perioperative myocardial ischemia and infarction during fentanyl anesthesia because of pancuronium. There are many other examples of remarkable differences in hemodynamics and clinical outcome that are often dependent on a single, often clinically imperceptible, difference in anesthetic technique. 15-i7 Thus, it is rational that clinicianresearchers should exert great efforts to study and improve anesthetic techniques and that their work should receive appropriate recognition for the clinical gains that result. It is in this light that the papers by Tuman et al,* Ruff and Reeves,’ Licina et al,3 and Milligan et al4 should be considered. Although critical reviewers of these studies could say, “what is so new and different about the benzodiazepine-opioid interaction?” let us think for a moment about some of the subtleties in clinical technique evaluated in these four studies. Ruff and Reves suggest that the sequence of fentanyl versus lorazepam as well as the dose, plasma concentration, and rate of delivery of each of the agents may be key.’ How interesting! Licina et al3 and Tuman et al* document that, after scopolamine and morphine premeditation, care-
fully titrated moderate doses of pancuronium, sufentanil, and midazolam during induction and maintenance of anesthesia, or appropriate doses of sufentanil and succinylcholine during induction and intubation, yielded stable hemodynamits, absence of increases in plasma catecholamines, and ideal clinical conditions. Nice! Finally, Milligan et al4 show that propofol infusions provide excellent anesthesia for major thoracic surgery with remarkably rapid recovery and possibly better arterial blood gas levels than those in patients given other, more conventional, anesthetic techniques. As expected, N,O decreased requirements for propofol. More interesting, N,O seemed to delay postoperative recovery. Fascinating! Again, extremely critical reviewers would say the group numbers in each of the studies are too small, there were many other variables, some of them inadequately controlled, and as a result the findings may be at best suggestive and certainly not definitive. Unfortunately, these criticisms are valid for almost all clinical studies, and, for that matter, most nonclinical research as well, given that our knowledge of what does affect outcome is so incomplete. Suffice it to say that although these reports of evaluations of four anesthetic techniques do not give definitive answers, they do provide interesting and perhaps extremely important suggestions of new approaches to the anesthetic management of patients having cardiothoracic operations. For this, they are valuable contributions that deserve to be carefully considered and evaluated in clinical practice and in subsequent investigations attempting to further perfect anesthetic techniques. Theodore H. Stanley,
MD
University of Utah School of Medicine Salt Lake City, UT
REFERENCES 1. Ruff R, Reves JG: Hemodynamic effects of a lorazepam-fentanyl anesthetic induction for coronary artery bypass surgery. J Cardiothorac Anesth 4:314-317, 1990 2. Tuman KJ, McCarthy RJ, El-Ganzouri AR, et al: Sufentanil-midazolam anesthesia for coronary artery surgery. J Cardiothorac Anesth 4:308-313, 1990 3. Licina MC, Newsome LR, Reeder DA, et al: Sufentanil and succinylcholine for rapid-sequence anesthetic induction and tracheal intubation: Hemodynamic and hormonal responses. J Cardiothorac Anesth 4:3 18-322, 1990
4. Milligan KR, Coppel DL, Johnstone JR, Cosgrove J: Propofol anesthesia for major thoracic surgery. J Cardiothorat Anesth 4:323-325, 1990 5. Stanley TH: Anesthesiology in the 21st century: Analgesic, sedative and anesthetic focusing. Int J Clin Monit Comput 3:21-51, 1986
thetics Anesth
6. Stanley TH: Opiates, receptors, and the new anesand anesthetic delivery systems. J Cardiothorac 1:503-509, 1987
SUBTLETIES OF ANESTHETIC TECHNIQUE
7. Stanley TH: The specialty of anesthesiology: Projections to the future. Semin Anesth 5:273-276,1986 8. Stanley TH, Webster LR: Anesthetic requirements and cardiovascular effects of fentanyl-oxygen and fentanyl-diazepam-oxygen anesthesia in man. Anesth Analg 57:411-416, 1978 9. Lunn JK, Stanley TH, Eisele J, et al: High-dose fentanyl anesthesia for coronary artery surgery: Plasma fentanyl concentrations and influence of nitrous oxide on cardiovascular responses. Anesth Analg 58:390-395, 1979 10. Stanley TH, Philbin DM, Coggins CH: Fentanyloxygen anesthesia for coronary artery surgery: Cardiovascular and antidiuretic hormone responses. Can Anaesth Sot J 26:168-172, 1979 11. Waller JL, Hug CC, Nagle DM, et al: Hemodynamic changes during fentanyl-oxygen anesthesia for aortocoronary bypass operation. Anesthesiology 55:212-217, 1981 12. Comstock MK, Carter JG, Moyers JR, et al: Rigidity and hypercarbia associated with high-dose fentanyl induction of anesthesia. Anesth Analg 60:362-363,198l
307
13. Wynands JE, Townsend GE, Wong P, et al: Blood pressure response and plasma fentanyl concentrations during high- and very high-dose fentanyl anesthesia for coronary artery surgery. Anesth Analg 62:661-665, 1983 14. Thomson IR, Pitman CL: Adverse effects of pancuronium during high-dose fentanyl anesthesia for coronary artery bypass grafting. Anesthesiology 62:708-713, 1985 15. Stoelting RK, Peterson C: Heart rate slowing and junctional rhythm following intravenous succinylcholine with and without intramuscular atropine preanesthetic medication. Anesth Analg 54:705-709, 1975 16. Gravlee GP, Ramsey RC, Roy RC: Rapid administration of a narcotic and neuromuscular blocker. A comparison of fentanyl, sufentanil, pancuronium, and vecuronium. Anesth Analg 67:39-49, 1988 17. Sill JC, Nugent M, Matert B: Influence of propranolo1 plasma levels on hemodynamics during coronary artery bypass surgery. Anesthesiology 60:453-463, 1984
CardiothoracicAnesthesia VOL 4, NO 3
JUNE 1990
EDITORIAL The Subtleties
of Anesthetic
T
HE FIRST FOUR articles in this issue of the JOURNAL concern themselves with the subtleties of anesthetic technique.lM4 Each of these contributions focuses attention on what, when, and how either the usual premedicants, anesthetics, and anesthetic adjuvants, or one of the new agents (propofol) or infusion approaches (computer-calculated and directed exponentially declining infusion of an opioid or benzodiazepine) is used as part of an anesthetic technique. All of the studies attempt to assess the impact of the particular anesthetic technique in question on hemodynamics and clinical outcome (incidence of myocardial ischemia or infarction, time of recovery, etc). The stated and unstated objectives of the four studies were: 1. to determine if the specific drugs, combinations of drugs, drug sequences, and/or infusion rates or techniques of infusion could optimize hemodynamics and clinical conditions and minimize or eliminate adverse side effects; 2. to judge if the anesthetic technique in question was superior to others using the same or related drugs or administration techniques; 3. to obtain insight as to additional changes that could be made in future studies to further optimize outcome; and 4. to uncover a new principle or fundamental truth. Although these goals are not new, they are noble, especially in the current environment where attempting “to understand a mechanism of action” generally earns more academic credit and is much more likely to be successful in winning a competitive research grant. While it is clear that anesthesiology and anesthesiologists need safer and better anesthetics and simpler, more reliable, less traumatic, and more costJournal of Cardiothoracic Anesthesia, Vol4,
No 3
(June), 1990:
Technique
effective techniques of administering these agents,5S7 it is also clear that as much or more attention needs to be spent improving our understanding of the drugs available today and deciding how we can best optimize their administration. Of course, this can only happen when interested clinician-researchers are willing to design and carefully implement clinical studies that highlight subtleties of anesthetic technique. The enormous impact that a subtle change in anesthetic technique can have on clinical outcome was first brought to my attention after our initial reports on high-dose fentanyl anesthesia and the subsequent attempts of others to repeat our studies.8-‘3 Our first reports did not describe the fact that before induction was begun with fentanyl, 3 mg of d-tubocurarine or 1 mg of pancuronium was administered.8-10 This omission occurred because all patients receiving succinylcholine in our institution were given small doses of these nondepolarizing muscle relaxants to prevent the fasciculations associated with succinylcholine. The practice was so ubiquitous we forgot to mention it in our manuscript. However, this very subtle point was extremely important regarding the incidence and magnitude of fentanyl-induced rigidity. We virtually never experienced rigidity with anesthetic doses of fentanyl in our hospital. Yet others attempting to repeat our studies and not knowing of our practice of administering a small dose of a nondepolarizing muscle relaxant just before induction found high incidences of severe chest wall rigidity. ‘lo* Rigidity after high doses of narcotics is rarely found in anesthetic practice today because clinicians now either administer a small dose of one of the many available nondepolarizing muscle relaxants before induction with a narcotic and paralysis with succinylcholine,3 or coadminister large doses of a nondepolarizing
pp 305-307
305
306
THEODORE H. STANLEY
muscle relaxant with the narcotic.’ The coadministration of a large dose of a nondepolarizing muscle relaxant is also a subtle change from our original description of high-dose fentanyl anesthesia. This subtle change often produced dramatic differences in the hemodynamic profile of highdose fentanyl anesthesia in the early days when a large dose of pancuronium was often used as the muscle relaxant. ‘i Instead of no change or slight reductions in heart rate, arterial blood pressure, and systemic resistance (as was found when succinylcholine was the muscle relaxant), increases in all of these variables were frequently seen, especially after endotracheal intubation and sternotomy. “Jo Thomson et ali4 even reported a higher incidence of perioperative myocardial ischemia and infarction during fentanyl anesthesia because of pancuronium. There are many other examples of remarkable differences in hemodynamics and clinical outcome that are often dependent on a single, often clinically imperceptible, difference in anesthetic technique. 15-i7 Thus, it is rational that clinicianresearchers should exert great efforts to study and improve anesthetic techniques and that their work should receive appropriate recognition for the clinical gains that result. It is in this light that the papers by Tuman et al,* Ruff and Reeves,’ Licina et al,3 and Milligan et al4 should be considered. Although critical reviewers of these studies could say, “what is so new and different about the benzodiazepine-opioid interaction?” let us think for a moment about some of the subtleties in clinical technique evaluated in these four studies. Ruff and Reves suggest that the sequence of fentanyl versus lorazepam as well as the dose, plasma concentration, and rate of delivery of each of the agents may be key.’ How interesting! Licina et al3 and Tuman et al* document that, after scopolamine and morphine premeditation, care-
fully titrated moderate doses of pancuronium, sufentanil, and midazolam during induction and maintenance of anesthesia, or appropriate doses of sufentanil and succinylcholine during induction and intubation, yielded stable hemodynamits, absence of increases in plasma catecholamines, and ideal clinical conditions. Nice! Finally, Milligan et al4 show that propofol infusions provide excellent anesthesia for major thoracic surgery with remarkably rapid recovery and possibly better arterial blood gas levels than those in patients given other, more conventional, anesthetic techniques. As expected, N,O decreased requirements for propofol. More interesting, N,O seemed to delay postoperative recovery. Fascinating! Again, extremely critical reviewers would say the group numbers in each of the studies are too small, there were many other variables, some of them inadequately controlled, and as a result the findings may be at best suggestive and certainly not definitive. Unfortunately, these criticisms are valid for almost all clinical studies, and, for that matter, most nonclinical research as well, given that our knowledge of what does affect outcome is so incomplete. Suffice it to say that although these reports of evaluations of four anesthetic techniques do not give definitive answers, they do provide interesting and perhaps extremely important suggestions of new approaches to the anesthetic management of patients having cardiothoracic operations. For this, they are valuable contributions that deserve to be carefully considered and evaluated in clinical practice and in subsequent investigations attempting to further perfect anesthetic techniques. Theodore H. Stanley,
MD
University of Utah School of Medicine Salt Lake City, UT
REFERENCES 1. Ruff R, Reves JG: Hemodynamic effects of a lorazepam-fentanyl anesthetic induction for coronary artery bypass surgery. J Cardiothorac Anesth 4:314-317, 1990 2. Tuman KJ, McCarthy RJ, El-Ganzouri AR, et al: Sufentanil-midazolam anesthesia for coronary artery surgery. J Cardiothorac Anesth 4:308-313, 1990 3. Licina MC, Newsome LR, Reeder DA, et al: Sufentanil and succinylcholine for rapid-sequence anesthetic induction and tracheal intubation: Hemodynamic and hormonal responses. J Cardiothorac Anesth 4:3 18-322, 1990
4. Milligan KR, Coppel DL, Johnstone JR, Cosgrove J: Propofol anesthesia for major thoracic surgery. J Cardiothorat Anesth 4:323-325, 1990 5. Stanley TH: Anesthesiology in the 21st century: Analgesic, sedative and anesthetic focusing. Int J Clin Monit Comput 3:21-51, 1986
thetics Anesth
6. Stanley TH: Opiates, receptors, and the new anesand anesthetic delivery systems. J Cardiothorac 1:503-509, 1987
SUBTLETIES OF ANESTHETIC TECHNIQUE
7. Stanley TH: The specialty of anesthesiology: Projections to the future. Semin Anesth 5:273-276,1986 8. Stanley TH, Webster LR: Anesthetic requirements and cardiovascular effects of fentanyl-oxygen and fentanyl-diazepam-oxygen anesthesia in man. Anesth Analg 57:411-416, 1978 9. Lunn JK, Stanley TH, Eisele J, et al: High-dose fentanyl anesthesia for coronary artery surgery: Plasma fentanyl concentrations and influence of nitrous oxide on cardiovascular responses. Anesth Analg 58:390-395, 1979 10. Stanley TH, Philbin DM, Coggins CH: Fentanyloxygen anesthesia for coronary artery surgery: Cardiovascular and antidiuretic hormone responses. Can Anaesth Sot J 26:168-172, 1979 11. Waller JL, Hug CC, Nagle DM, et al: Hemodynamic changes during fentanyl-oxygen anesthesia for aortocoronary bypass operation. Anesthesiology 55:212-217, 1981 12. Comstock MK, Carter JG, Moyers JR, et al: Rigidity and hypercarbia associated with high-dose fentanyl induction of anesthesia. Anesth Analg 60:362-363,198l
307
13. Wynands JE, Townsend GE, Wong P, et al: Blood pressure response and plasma fentanyl concentrations during high- and very high-dose fentanyl anesthesia for coronary artery surgery. Anesth Analg 62:661-665, 1983 14. Thomson IR, Pitman CL: Adverse effects of pancuronium during high-dose fentanyl anesthesia for coronary artery bypass grafting. Anesthesiology 62:708-713, 1985 15. Stoelting RK, Peterson C: Heart rate slowing and junctional rhythm following intravenous succinylcholine with and without intramuscular atropine preanesthetic medication. Anesth Analg 54:705-709, 1975 16. Gravlee GP, Ramsey RC, Roy RC: Rapid administration of a narcotic and neuromuscular blocker. A comparison of fentanyl, sufentanil, pancuronium, and vecuronium. Anesth Analg 67:39-49, 1988 17. Sill JC, Nugent M, Matert B: Influence of propranolo1 plasma levels on hemodynamics during coronary artery bypass surgery. Anesthesiology 60:453-463, 1984