Supplemental Intraoperative Oxygen Augments Antimicrobial and Proinflammatory Responses of Alveolar Macrophages

Background: The first goal was to test the hypothesis that 100% inspired oxygen maintained for approximately 8 h intraoperatively is not associated with impaired pulmonary oxygenation. The authors also tested the hypothesis that intraoperative inhalation of 100% oxygen augments proinflammatory and antimicrobial responses of alveolar macrophages during anesthesia and surgery.

Methods: The authors studied patients administered 100% oxygen (n = 30) and 30% oxygen (n = 30) during propofol-fentanyl general anesthesia. Alveolar macrophages were harvested by bronchoalveolar lavage immediately, 2, 4, and 6 h after induction of anesthesia, and at the end of surgery.The authors measured "opsonized" and "unopsonized" phagocytosis and microbicidal activity. RNA was extracted from harvested cells and cDNA was synthesized. The expression of interleukin(IL)-1[beta], IL-6, IL-8, interferon-[gamma] (IFN-[gamma]) and tumor necrosis factor [alpha] (TNF-[alpha]) was measured by semiquantitative polymerase chain reaction.

Results: Gene expression of all proinflammatory cytokines except IL-6 increased fourfold to 20-fold over time in both groups. However, expression of TNF-[alpha] and IL-8, IFN-[gamma], and IL-6 and IL-1[beta] was 2-20 times greater in patients administered 100% than in those administered 30% oxygen. Unopsonized and opsonized phagocytosis and microbicidal activity decreased progressively, with the decreases being nearly twice as great during inhalation of 30% oxygen versus 100% oxygen.     

Lung perfusion,shunt fraction,and oxygenation during one-lung ventilation in pigs: the effects of desflurane,isoflurane, and propofol

OBJECTIVE: To study how desflurane, isoflurane, and propofol affect pulmonary perfusion, shunt fraction, and systemic oxygenation during one-lung ventilation (OLV) in vivo. DESIGN: Prospective animal study with a crossover design. SETTING: Animal laboratory of a university hospital. PARTICIPANTS: Twelve female pigs. INTERVENTIONS: The pigs were anesthetized, tracheally intubated, and mechanically ventilated. After placement of femoral arterial and thermodilution pulmonary artery catheters, a left-sided, double-lumen tube (DLT) was placed via tracheotomy. After DLT placement, F(I)O(2) was adjusted at 0.8, and anesthesia was continued in random order with 1 minimal alveolar concentration of desflurane, 1 minimal alveolar concentration of isoflurane, or propofol. MEASUREMENTS AND MAIN RESULTS: Measurements of respiratory and hemodynamic parameters were made after stabilization at each anesthetic. During OLV, perfusion of the nonventilated lung and shunt fraction were comparable during all 3 anesthetics. PaO(2) was lower during desflurane and isoflurane anesthesia as compared with propofol anesthesia. Mixed venous PO(2) and cardiac output were lower with desflurane and isoflurane as compared with propofol. CONCLUSIONS: In a clinically relevant model of OLV cardiac output, PaO(2) and mixed venous PO(2) decreased during desflurane and isoflurane as compared with propofol, whereas perfusion of the nonventilated lung and shunt fraction remained comparable.     

Supplemental intraoperative oxygen augments antimicrobial and proinflammatory responses of alveolar macrophages

BACKGROUND: The first goal was to test the hypothesis that 100% inspired oxygen maintained for approximately 8 h intraoperatively is not associated with impaired pulmonary oxygenation. The authors also tested the hypothesis that intraoperative inhalation of 100% oxygen augments proinflammatory and antimicrobial responses of alveolar macrophages during anesthesia and surgery. METHODS: The authors studied patients administered 100% oxygen (n = 30) and 30% oxygen (n = 30) during propofol-fentanyl general anesthesia. Alveolar macrophages were harvested by bronchoalveolar lavage immediately, 2, 4, and 6 h after induction of anesthesia, and at the end of surgery. The authors measured "opsonized" and "unopsonized" phagocytosis and microbicidal activity. RNA was extracted from harvested cells and cDNA was synthesized. The expression of interleukin(IL)-1beta, IL-6, IL-8, interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) was measured by semiquantitative polymerase chain reaction. RESULTS: Gene expression of all proinflammatory cytokines except IL-6 increased fourfold to 20-fold over time in both groups. However, expression of TNF-alpha and IL-8, IFN-gamma, and IL-6 and IL-1beta was 2-20 times greater in patients administered 100% than in those administered 30% oxygen. Unopsonized and opsonized phagocytosis and microbicidal activity decreased progressively, with the decreases being nearly twice as great during inhalation of 30% oxygen versus 100% oxygen. CONCLUSION: Inhalation of 100% oxygen improved intraoperative decreases in phagocytic and microbicidal activity possibly because expression of proinflammatory cytokines was augmented. These data therefore suggest that intraoperative inhalation of 100% oxygen augments antimicrobial and proinflammatory responses in alveolar macrophages during anesthesia and surgery.     

Recovery of Intraoperative Microbicidal and Inflammatory Functions of Alveolar Immune Cells after a Tobacco Smoke-free Period

Background: Tobacco smoking inhibits alveolar macrophage function, but cessation of smoking markedly reduces the risk of postoperative pulmonary complications. The authors therefore evaluated the effect of nonsmoking duration on both antimicrobial and inflammatory functions of alveolar macrophages during anesthesia and surgery.

Methods: The authors studied 15 patients who had never smoked, 15 current smokers, and 41 former smokers, all of whom underwent general anesthesia. Former smokers were further allocated to one of three groups depending on their smoke-free periods: 2 months (n = 13), 3-5 months (n = 13), and 6-12 months (n = 15). Alveolar immune cells were collected by bronchoalveolar lavage immediately after induction of anesthesia, at 2 and 4 h after induction of anesthesia, and at the end of surgery. Opsonized and nonopsonized phagocytosis were measured. Microbicidal activity was determined as the ability of the macrophages to kill Listeria monocytogenes directly. Finally, we determined the expression of proinflammatory cytokines, including interleukin 1[latin sharp s], interleukin 8, interferon [gamma], and tumor necrosis factor [alpha], and of antiinflammatory cytokines (interleukin 4 and 10) by semiquantitative polymerase chain reaction.

Results: Nonopsonized and opsonized phagocytosis and microbicidal activity of alveolar macrophages (antimicrobial functions) decreased 20-50%, and the expression of genes for all proinflammatory and antiinflammatory cytokines increased 3-30-fold over time in all groups. Starting 4 h after induction of anesthesia, the decreases in antimicrobial functions were 1.5-3 times greater in current and former smokers (2 months' abstinence) than in patients who had never smoked. Starting 4 h after anesthesia, the increase in expression of all cytokines, except interleukin 8, was twofold to fivefold less in current and former smokers (2-6 months' abstinence) than in patients who had never smoked.     

Isoflurane and Sevoflurane Anesthesia in Pigs with a Preexistent Gas Exchange Defect

Background : Decreased arterial partial pressure of oxygen (Pao2) during volatile anesthesia is well-known. Halothane has been examined with the multiple inert gas elimination technique and has been shown to alter the distribution of pulmonary blood flow and thus Pao2. The effects of isoflurane and sevoflurane on pulmonary gas exchange remain unknown. The authors hypothesized that sevoflurane with a relatively high minimum alveolar concentration (MAC) would result in significantly more gas exchange disturbances in comparison with isoflurane or control.

Methods : This study was performed in a porcine model with an air pneumoperitoneum that generates a reproducible gas exchange defect. After a baseline measurement of pulmonary gas exchange (multiple inert gas elimination technique) during propofol anesthesia, 21 pigs were randomly assigned to three groups of seven animals each. One group received isoflurane anesthesia, one group received sevoflurane anesthesia, and one group was continued on propofol anesthesia (control). After 30 min of volatile anesthesia at 1 MAC or propofol anesthesia, a second measurement (multiple inert gas elimination technique) was performed.

Results : At the second measurement, inert gas shunt was 15 +/- 3% (mean +/- SD) during sevoflurane anesthesia versus 9 +/- 1% during propofol anesthesia (P = 0.02). Blood flow to normal ventilation/perfusion ( A/ ) lung areas was 83 +/- 5% during sevoflurane anesthesia versus 89 +/- 1% during propofol anesthesia (P = 0.04). This resulted in a Pao2 of 88 +/- 11 mmHg during sevoflurane anesthesia versus 102 +/- 15 mmHg during propofol anesthesia (P = 0.04). Inert gas and blood gas variables during isoflurane anesthesia did not differ significantly from those obtained during propofol anesthesia.     

Recovery of intraoperative microbicidal and inflammatory functions of alveolar immune cells after a tobacco smoke-free period

BACKGROUND: Tobacco smoking inhibits alveolar macrophage function, but cessation of smoking markedly reduces the risk of postoperative pulmonary complications. The authors therefore evaluated the effect of nonsmoking duration on both antimicrobial and inflammatory functions of alveolar macrophages during anesthesia and surgery. METHODS: The authors studied 15 patients who had never smoked, 15 current smokers, and 41 former smokers, all of whom underwent general anesthesia. Former smokers were further allocated to one of three groups depending on their smoke-free periods: 2 months (n = 13), 3-5 months (n = 13), and 6-12 months (n = 15). Alveolar immune cells were collected by bronchoalveolar lavage immediately after induction of anesthesia, at 2 and 4 h after induction of anesthesia, and at the end of surgery. Opsonized and nonopsonized phagocytosis were measured. Microbicidal activity was determined as the ability of the macrophages to kill Listeria monocytogenes directly. Finally, we determined the expression of proinflammatory cytokines, including interleukin 1beta, interleukin 8, interferon gamma, and tumor necrosis factor alpha, and of antiinflammatory cytokines (interleukin 4 and 10) by semiquantitative polymerase chain reaction. RESULTS: Nonopsonized and opsonized phagocytosis and microbicidal activity of alveolar macrophages (antimicrobial functions) decreased 20-50%, and the expression of genes for all proinflammatory and antiinflammatory cytokines increased 3-30-fold over time in all groups. Starting 4 h after induction of anesthesia, the decreases in antimicrobial functions were 1.5-3 times greater in current and former smokers (2 months' abstinence) than in patients who had never smoked. Starting 4 h after anesthesia, the increase in expression of all cytokines, except interleukin 8, was twofold to fivefold less in current and former smokers (2-6 months' abstinence) than in patients who had never smoked. CONCLUSION: Our data suggest that former smokers may have a limited ability to mount effective pulmonary immune defenses for long as 6 months after stopping cigarette use.     

Propofol anesthesia enhances pressor response to ephedrine in patients given clonidine.

We studied the hemodynamic effects of ephedrine in patients with or without clonidine premedication during either isoflurane or propofol anesthesia. Forty adult patients were randomly assigned to one of two groups: 20 patients received famotidine 20 mg orally (control group) and 20 received clonidine 3 microg/kg and famotidine 20 mg orally (clonidine group). Within each group, 10 patients were then anesthetized with isoflurane and 10 with propofol. Hemodynamic measurements were taken at 1-min intervals for 10 min after a bolus injection of ephedrine 0.1 mg/kg. The magnitude of the maximal pressor response to ephedrine was no different whether patients without clonidine were anesthetized with isoflurane (increase 5+/-7 mm Hg) or propofol (3+/-9 mm Hg); however, this response was greater (P<0.05) with propofol (17+/-6 mm Hg) versus isoflurane (6+/-5 mm Hg) in patients given clonidine. The arterial blood pressure increase in clonidine-premedicated patients with propofol anesthesia was the largest among the four subgroups. The heart rate response to ephedrine was not significant in patients anesthetized with isoflurane and was small but significant in those anesthetized with propofol. The present results, together with previous studies on the effect of ephedrine in patients medicated with clonidine, suggest that the interaction between clonidine and ephedrine is modulated by the anesthetic used. IMPLICATIONS: We evaluated the pressor response to ephedrine during isoflurane or propofol anesthesia with or without clonidine premedication. Our study suggests that, in anesthetized patients premedicated with clonidine, decreases in blood pressure may be easier to reverse with ephedrine with some types of anesthesia (e.g., propofol) than with others (e.g., isoflurane).     

麻醉相关效应：丙泊酚麻醉患者的手术后疼痛轻于异氟烷麻醉患者

背景临床前期实验显示某些挥发性麻醉药可能通过抑制烟碱受体引起痛觉过敏。早期的实验证实，给予异氟烷麻醉的女性患者鼻腔内喷雾烟碱，具有手术后镇痛作用。为了确定烟碱是逆转了异氟烷引起的痛觉过敏，还是单纯充当了镇痛药的角色，本研究探讨了烟碱对异氟烷＋芬太尼或丙泊酚＋芬太尼麻醉的女性患者手术后疼痛的影响。方法此项随机、前瞻、双盲研究，对80例采用异氟烷或丙泊酚麻醉行开腹子宫手术的女性患者加以研究。在2个麻醉组中，受试者又被随机分为烟碱3mg组或安慰剂组。数字模拟疼痛评分是首要的观察指标。结果患者的基本情况相似。丙泊酚麻醉组手术后第1天的疼痛评分及吗啡用量要小于异氟烷麻醉组（P〈0．01，P〈0．01）。烟碱的使用没有改变任一组的疼痛评分及吗啡用量（P〉0．05）。结论采用丙泊酚行全身麻醉的患者手术后疼痛及吗啡用量要小于异氟烷麻醉的患者。本研究中烟碱不具有镇痛作用。若上述结果在其他人群中具有可重复性，那么丙泊酚麻醉除具有以前报道的改善恶心、呕吐外的潜在优势外，还能减轻手术后疼痛。     

Isoflurane and sevoflurane anesthesia in pigs with a preexistent gas exchange defect.

BACKGROUND: Decreased arterial partial pressure of oxygen (PaO2) during volatile anesthesia is well-known. Halothane has been examined with the multiple inert gas elimination technique and has been shown to alter the distribution of pulmonary blood flow and thus PaO2. The effects of isoflurane and sevoflurane on pulmonary gas exchange remain unknown. The authors hypothesized that sevoflurane with a relatively high minimum alveolar concentration (MAC) would result in significantly more gas exchange disturbances in comparison with isoflurane or control. METHODS: This study was performed in a porcine model with an air pneumoperitoneum that generates a reproducible gas exchange defect. After a baseline measurement of pulmonary gas exchange (multiple inert gas elimination technique) during propofol anesthesia, 21 pigs were randomly assigned to three groups of seven animals each. One group received isoflurane anesthesia, one group received sevoflurane anesthesia, and one group was continued on propofol anesthesia (control). After 30 min of volatile anesthesia at 1 MAC or propofol anesthesia, a second measurement (multiple inert gas elimination technique) was performed. RESULTS: At the second measurement, inert gas shunt was 15 +/- 3% (mean +/- SD) during sevoflurane anesthesia versus 9 +/- 1% during propofol anesthesia (P = 0.02). Blood flow to normal ventilation/perfusion (V(A)/Q) lung areas was 83 +/- 5% during sevoflurane anesthesia versus 89 +/- 1% during propofol anesthesia (P = 0.04). This resulted in a PaO2 of 88 +/- 11 mmHg during sevoflurane anesthesia versus 102 +/- 15 mmHg during propofol anesthesia (P = 0.04). Inert gas and blood gas variables during isoflurane anesthesia did not differ significantly from those obtained during propofol anesthesia. CONCLUSIONS: In pigs with an already existent gas exchange defect, sevoflurane anesthesia but not isoflurane anesthesia causes significantly more gas exchange disturbances than propofol anesthesia does.     

The effect of halothane, isoflurane, sevoflurane and propofol infusion on renal function after coronary artery bypass surgery

Renal insufficiency after cardiac surgery is associated with increased mortality, morbidity, and length of stay in the intensive care unit. We investigated the effect of isoflurane, halothane, sevoflurane and propofol anesthesia on perioperative renal function following elective coronary artery surgery. The medical records of 224 patients, in the Hacettepe University Medical Faculty Hospital who had undergone cardiac surgery in one year, were retrospectively reviewed. 65 (29%) patients received isoflurane, 68 (30%) patients received halothane, 64 (29%) patients received sevoflurane, and 27 (12%) patients received propofol infusion as part of maintenance anesthesia for coronary artery bypass surgery. Patient characteristics (age, sex, preoperative ejection fraction), operative data (duration of CPB, duration of operation, number of distal anastomoses, usage of diuretic, intraoperative crystalloid and blood transfusion), intraoperative urinary output, preoperative and postoperative (6th hours and 24th hours) BUN and plasma creatinine levels, were not statistically significant between and within groups. Intraoperative inotropic agent (dopamine) was used in 8 (12.3%) patients in the isoflurane group, in 10 (14.7%) patients in the halothane group, in 11 (17.2%) patients in sevoflurane group and in 9 (33.3%) patients in the propofol group. Postoperatively fluid and blood transfusion, postoperative drainage, urinary output, diuretic usage were smiliar between the four groups (p>0,05). Inotropic agent was used in 8 (12.3%) patients in the isoflurane group, in 9 (13.2%) patients in the halothane group, in 16 (25%) patients in the sevoflurane group and in 7 (25.9%) patients in the propofol group. It is concluded that, halothane, isoflurane, sevoflurane and propofol infusion anesthesia as part of anesthesia maintenance for elective coronary artery bypass surgery does not affect early postoperative renal functions.     

异丙酚麻醉下PaCO2对SjvO2影响的年龄差异

目的研究异氟醚和异丙酚维持神经外科手术中低碳酸和高碳酸血症对颈静脉球血氧饱和度(SjvO     

Comparison of the effects of propofol and isoflurane anaesthesia on right ventricular function and shunt fraction during thoracic surgery

I.v. anaesthetic agents, including propofol, have not been shown to inhibit hypoxic pulmonary vasoconstriction (HPV). This may encourage the use of propofol in thoracic surgery where one lung ventilation (OLV) is required. We have compared the effects of maintaining anaesthesia with either isoflurane or propofol infusion on right ventricular function and shunt fraction. We studied 10 patients who received isoflurane and 12 who received propofol. When OLV commenced there was a greater reduction in both mean cardiac index (3.2 (SEM 0.2) to 2.4 (0.1) litre min-1 m-2 for propofol, and 3.4 (0.2) to 3.3 (0.4) litre min-1 m-2 for isoflurane) and right ventricular ejection fraction (0.45 (0.03) to 0.37 (0.02) for propofol, and 0.48 (0.02) to 0.42 (0.02) for isoflurane) in patients who received propofol. Furthermore, these reductions were sustained for longer in the propofol group. However, propofol was not associated with a significant increase in shunt fraction during OLV, which increased threefold in patients who received isoflurane.      

Endoscopic transthoracic sympathicotomy and peripheral microcirculation: effects of electric sympathetic chain stimulation,thermocoagulation and anaesthetic agents

Summary. Summary.   Background: During endoscopic transthoracic sympathicotomy (ETS) in patients with hyperhidrosis it is useful to assess the effect of surgery peroperatively. However, the autonomic system is affected in various ways by different anesthetic agents. In the present study, the effect of ETS during either isoflurane or propofol anesthesia was evaluated by measuring changes in the finger pulp microcirculation using laser Doppler flowmetry (LDF). Electric stimulation of the sympathetic chain was used for identifying the sympathetic chain and to explore whether the anesthetic agents differentially influenced the LDF response to stimulation.   Methods: From a group of 12 patients with incapacitating palmar hyperhidrosis, six were randomly assigned to isoflurane and six to propofol anesthesia. LDF probes were attached to the ipsilateral finger pulp for continuous recording of peripheral blood flow during the ETS procedure. Electric stimulation (1 Hz, 10 Hz, and 100 Hz) was applied to the sympathetic paravertebral chain at the levels of the 2nd and 3rd sympathetic ganglia via a custom designed bipolar electrode. In eight of the patients LDF recordings were also performed in the awake state and compared with records obtained from eight healthy subjects.   Findings: In patients anesthetized with isoflurane, the base line finger pulp blood flow did not significantly differ from that of awake normal subjects, while those anesthetized with propofol had a lower base line flow, similar to that of awake subjects with hyperhidrosis. Stimulation of the sympathetic chain induced marked reduction of finger pulp microcirculation in both anesthetic groups, and this effect was frequency dependant during isoflurane anesthesia. After ETS a significant increase in flow was recorded only in the propofol group.  Interpretation. The study demonstrates that the completeness of the sympathicotomy can only be peroperatively evaluated if an anesthetic agent with relatively low vasodilatory capacity, as e.g. propofol, is utilized.     

Electroencephalogram Approximate Entropy Correctly Classifies the Occurrence of Burst Suppression Pattern as Increasing Anesthetic Drug Effect

Background: Approximate entropy, a measure of signal complexity and regularity, quantifies electroencephalogram changes during anesthesia. With increasing doses of anesthetics, burst-suppression patterns occur. Because of the high-frequency bursts, spectrally based parameters such as median electroencephalogram frequency and spectral edge frequency 95 do not decrease, incorrectly suggesting lightening of anesthesia. The authors investigated whether the approximate entropy algorithm correctly classifies the occurrence of burst suppression as deepening of anesthesia.

Methods: Eleven female patients scheduled for elective major surgery were studied. After propofol induction, anesthesia was maintained with isoflurane only. Before surgery, the end-tidal isoflurane concentration was varied between 0.6 and 1.3 minimum alveolar concentration. The raw electroencephalogram was continuously recorded and sampled at 128 Hz. Approximate entropy, electroencephalogram median frequency, spectral edge frequency 95, burst-suppression ratio, and burst-compensated spectral edge frequency 95 were calculated offline from 8-s epochs. The relation between burst-suppression ratio and approximate entropy, electroencephalogram median frequency, spectral edge frequency 95, and burst-compensated spectral edge frequency 95 was analyzed using Pearson correlation coefficient.

Results: Higher isoflurane concentrations were associated with higher burst-suppression ratios. Electroencephalogram median frequency (r = 0.34) and spectral edge frequency 95 (r = 0.29) increased, approximate entropy (r = -0.94) and burst-compensated spectral edge frequency 95 (r = -0.88) decreased with increasing burst-suppression ratio.     

No implicit memory for stories played during isoflurane/alfentanil/nitrous oxide anesthesia: a reading speed measurement

Implicit memory of intraoperatively presented stories was recently detected by using the reading speed paradigm during propofol-alfentanil-nitrous oxide anesthesia. Our main goal was to evaluate the reading speed test procedure under another anesthetic regimen, i.e., isoflurane combined with nitrous oxide and alfentanil-infusion. In both experiments, patients were premedicated with oral midazolam. In a previous experiment, patients postoperatively read "old" stories that had been presented during anesthesia quicker compared with "new," unpresented stories. The same study design and test material as in the previous experiment were used. One of two audio tapes with two short stories was played randomly to patients during lumbar disk surgery and to awake controls. Approximately 7 h later, a structured interview and the reading speed test were used to determine whether the participants had any explicit or implicit memories of the presented stories. The results of 30 patients and 30 controls were calculated. Whereas the control participants showed an intact explicit and implicit memory of the previously presented material, no such effect was found in the anesthetized patients. The present experiment shows that changing the main anesthetic in otherwise equal study conditions, i. e., propofol to isoflurane (end-expiratory 0.7%), implicit memory is abolished in anesthetized patients. IMPLICATIONS: We showed that implicit memory during general anesthesia can be abolished by changing the hypnotic anesthetic. Increased postoperative reading speed for stories presented during propofol-alfentanil-nitrous oxide anesthesia was shown in a previous experiment, but not in our study using isoflurane for balanced anesthesia.     

Effects of Propofol or Isoflurane Anesthesia on Cardiac Conduction in Children Undergoing Radiofrequency Catheter Ablation for Tachydysrhythmias

Background: To determine suitability for ablation procedures in children, two commonly used anesthetic agents were studied: propofol and isoflurane.

Methods: Twenty patients presenting for a radiofrequency catheter ablation procedure were included and randomly assigned to two groups. A baseline electrophysiology study was performed during anesthesia with thiopental, alfentanil, nitrous oxide, and pancuronium in all patients. At the completion of the baseline electrophysiology study (EPS), 0.8-1.2% isoflurane was administered to patients in group 1 and 2 mg/kg propofol bolus plus an infusion of 150 micro gram *symbol* kg sup -1 *symbol* min sup -1 was administered to patients in group 2. Nitrous oxide and pancuronium were used throughout the procedure. After 30 min of equilibration, both groups underwent a repeat EPS. The following parameters were measured during the EPS: cycle length, atrial-His interval, His-ventricle interval, corrected sinus node recovery time, AV node effective refractory period, and atrial effective refractory period. Using paired t tests, the electrophysiologic parameters described above measured during propofol or isoflurane anesthesia were compared to those measured during baseline anesthesia. Statistical significance was accepted as P < 0.05.

Results: There was no statistically significant difference in the results obtained during baseline anesthesia when compared with those measured during propofol or isoflurane anesthesia.     

Sevoflurane Provides Greater Protection of the Myocardium than Propofol in Patients Undergoing Off-pump Coronary Artery Bypass Surgery

Background: Sevoflurane, like other halogenated anesthetics, has been shown to have a protective effect on the myocardium at risk after an ischemic injury. The current study tested the hypothesis that such beneficial effects, so far mainly seen in the laboratory, are reproducible in humans.

Methods: After institutional review board approval, 20 patients scheduled to undergo elective off-pump coronary artery bypass surgery were randomized to receive general anesthesia with either sevoflurane or propofol. Except for this, anesthetic and surgical management was the same in both groups. For assessing myocardial injury, troponin I and myocardial fraction of creatine kinase were determined during the first 24 postoperative hours. Systemic hemodynamic variables were measured before, during, and after completion of coronary artery bypass.

Results: Troponin I concentrations increased significantly more in propofol-anesthetized patients than in patients anesthetized with sevoflurane.