Biomedical subjects

N L Pace

Publications and source records attributed to N L Pace.

At least 55 records · Page 3Linked to original sources

PubMed1990

Differences in magnitude and duration of opioid-induced respiratory depression and analgesia with fentanyl and sufentanil.

The magnitude and duration of analgesia and respiratory depression induced by fentanyl (1.0, 2.0, and 4.0 micrograms/kg) and sufentanil (0.1, 0.2, and 0.4 microgram/kg) after intravenous administration over 30 s were measured in 30 healthy young adult male volunteers divided into three groups and studied in a double-blind, randomized fashion. Each volunteer received one dose of fentanyl or sufentanil and no sooner than 48 h later, the corresponding equipotent dose of the other opioid. End-tidal CO2 and ventilatory and occlusion pressure responses to CO2 rebreathing were used to measure drug-induced respiratory effects. Analgesic effects were assessed by changes in the pain threshold to electric shock applied to the forearm. Plasma levels of fentanyl and sufentanil were measured by radioimmunoassay. Testing and sampling intervals were 5, 30, 60, 90, 120, 240, 300, and 360 min after drug administration. The magnitude and duration of depression of the ventilatory and occlusion pressure response were significantly less with sufentanil compared with fentanyl, irrespective of dose. Ventilatory and occlusion pressure responses returned to control values by 30 and 30 min, respectively, after sufentanil and by 240 and 120 min, respectively, after fentanyl. Statistically significant elevations of the pain threshold were, however, greater and longer lasting after sufentanil compared with fentanyl. Pain threshold returned to control values 180 min after sufentanil but only 90 min after fentanyl. These results suggest that sufentanil may provide better patient comfort with less respiratory depression than does fentanyl.

Adolescent↗

PubMed1990

Prevention of succinylcholine myalgias: a meta-analysis.

Meta-analysis is a term used to describe statistical methods for evaluating a series of research reports; this analysis transcends the limitations that may be inherent in each of the individual studies summarized. Forty-five research reports of clinical trials for the prevention of myalgias after succinylcholine were assembled. Four classes of preventive drugs (nondepolarizing muscle relaxants, benzodiazepines, succinylcholine in "self-taming" doses, and local anesthetics) were reported in detail sufficient to allow for inclusion in a meta-analysis of clinical efficacy. Each study was summarized by determining the difference in the incidence of myalgias on the first postoperative day between treatment and control groups. A random-effects variance components approach was used. Seven meta-analyses were performed (atracurium, d-tubocurarine, gallamine, pancuronium, diazepam, succinylcholine in self-taming doses, and lidocaine). For each meta-analysis there was statistically significant heterogeneity among studies. Atracurium, d-tubocurarine, gallamine, pancuronium, diazepam, and lidocaine all significantly decreased the frequency of myalgias by about 30%. Succinylcholine in self-taming doses alone was not efficacious.

Humans↗

PubMed1989

Implementation of a computerized patient advice system using the HELP clinical information system.

A COMputerized Patient Advice System (COMPAS) was designed to test the feasibility of using the HELP clinical information system to direct the respiratory therapy of intensive care (ICU) patients acutely ill with adult respiratory distress syndrome. A modified black-board control architecture allowed the application of knowledge in either a forward or a backward chaining mode. Expert clinicians recommended decision logic and actions for five different modes of ventilatory support. The clinical staff used COMPAS to manage the ICU ventilatory support of five patients for a total of 624 hr. During that time there were 407 decision-making opportunities. COMPAS automatically generated therapy suggestions 379 (93.1%) times and the clinical staff accepted COMPAS's recommendation in 320 (84.4%) of these cases. These results suggest that the ventilatory support of severely ill ICU patients can be managed by a clinical information system using a blackboard control architecture.

Algorithms↗

PubMed1989

Comparison of oral transmucosal fentanyl citrate and an oral solution of meperidine, diazepam, and atropine for premedication in children.

The safety and efficacy of premedication with oral transmucosal fentanyl citrate (OTFC) was compared with that of an orally administered solution of meperidine, diazepam, and atropine and no premedication in 59 children about to undergo elective operations. The patients were randomly assigned to receive no premedication (n = 19); 0.25 ml/kg of the oral solution (containing meperidine, 1.5 mg/kg, diazepam, 0.2 mg/kg, and atropine, 0.02 mg/kg, n = 20); or OTFC (15-20 micrograms/kg, n = 20). Children had activity (sedation) and anxiety scores, vital signs (including systolic and diastolic arterial blood pressures and heart and respiratory rates) and pulse oximetry determined oxygen saturation measured before and at 10-min intervals after premedication until they were taken to the operating room. Quality of induction and recovery was evaluated using scoring schedules; recovery times were measured and side effects noted. OTFC was readily accepted and provided significant reductions in preoperative activity (sedation) and anxiety starting after 30 min. After OTFC, sedation and anxiolysis were significantly greater than in children having no premedication but similar to children having the oral solution for premedication. Vital signs and oxygen saturations remained unchanged preoperatively in all groups. Induction and recovery evaluations and recovery times were similar in the three groups, although children having OTFC had the lowest requirements for narcotics in the recovery room. OTFC caused an 80% incidence of mild preoperative facial pruritus and a higher overall incidence of postoperative vomiting (37%) than premedication with the oral solution (5%) or no premedication (18%).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1989

The Utah anesthesia workstation.

A prototype anesthesia workstation has been developed to demonstrate the feasibility of a computer-assisted anesthesia workplace. The workstation provides a central display of information and aids the user in controlling and monitoring the anesthesia delivery system. The anesthesiologist interacts with the workstation through a Macintosh computer, which is easy for the clinician to understand and to use. Seventeen sensors and monitors transmit information from the anesthesia delivery system to the computer. The computer monitors this information using a set of rules, evaluated once each breath, to detect changes in the delivery system. If an event is detected, the computer alerts the anesthesiologist with a diagram, a text message, and an audible warning. A laboratory test of the monitoring system was performed to see if it properly identified 26 different critical events during simulated low flow and closed circuit anesthesia. Five hundred and eight-three of 660 simulated critical events (88%) were identified with the unique and correct message. On 35 occasions, multiple messages were displayed, including the correct one. Critical events were misidentified or not detected 42 times. Eight false positive alarms occurred during the 20 h of testing; all occurred as a result of baseline drift in a single transducer. These results demonstrate that a sophisticated monitoring system can reliably diagnose specific anesthesia machine failures.

Anesthesiology↗

PubMed1989

Evaluation of a replenishment type oxygen consumption monitor.

This paper describes the testing of a monitor (Oxyconsumeter) which uses a replenishment technique to measure oxygen consumption (VO2). Oxygen is added to the expired gas to replace the oxygen consumed by the patient. The replenishing oxygen flow equals the patients's VO2 when the mixed replenished expired oxygen fraction equals the inspired oxygen fraction. The accuracy of the Oxyconsumeter was assessed using a N2 and CO2 dilution technique. When tested over the operating range specified by the manufacturer, the bias of the Oxyconsumeter was 1.66% of reading. The reproducibility averaged 6.96% of reading. The reproducibility did not change with VO2, FIO2 or minute ventilation. The replenishment technique has the theoretical advantage that an absolute oxygen sensor calibration is not necessary and a respiratory flowmeter is not needed. It appears, from the laboratory testing, that the Oxyconsumeter has sufficient accuracy for use in the critical care setting.

Equipment Design↗

PubMed1989

Oral transmucosal fentanyl citrate (lollipop) premedication in human volunteers.

The authors determined whether fentanyl incorporated into a candy lollipop, oral transmucosal fentanyl citrate (OTFC), would cross mucosal tissues of the mouth in sufficient quantities during and after dissolution to produce sedation and/or analgesia. Associated respiratory and circulatory changes, side effects, and plasma concentrations of fentanyl were also measured. The evaluations were done in 28 adult volunteers who received fentanyl citrate in doses of 5, 4, 2, 1, and 0.5 mg in OTFC and rapidly sucked the lollipops (N = 20) or allowed them to passively dissolve (N = 8). Rapid consumption of OTFC resulted in more rapid onset of a pleasant feeling (first subjective sensation) but not more rapid onset of objective sedation or analgesia than passive dissolution. There was a significant correlation between dose of OTFC and magnitude of sedation (P less than 0.001, Spearman rank correlation = -0.82). Higher doses of OTFC produced greater and longer lasting analgesia and respiratory depression and a higher incidence of nausea and vomiting than lower doses, but pruritus (33%-87%) was not related to the dose of OTFC. Heart rate and arterial blood pressures were not changed by any dose of OTFC. The data indicate that low doses of OTFC (0.5 and 1 mg, equivalent to 5-20 micrograms.kg-1 of fentanyl citrate) produce analgesia and sedation with minimal side effects and little respiratory depression in adult volunteers and deserve further evaluation in patients.

Absorption↗

PubMed1989

Oral transmucosal fentanyl citrate premedication in children.

The authors evaluated the safety and efficacy of four doses of oral transmucosal fentanyl citrate (OTFC) as a premedicant in 44 children about to undergo elective operations. The patients received 5-10, 10-15, 15-20, or 20-25 micrograms.kg-1 of OTFC in the holding area and had activity (sedation) scores, vital signs (including systolic and diastolic arterial blood pressures, heart, and respiratory rates), and pulse oximetry determined oxygen saturation measured before and at 15-min intervals after premedication until they were taken to the operating room. Cooperation during anesthetic induction, and quality and speed of recovery room emergence were measured and side effects noted. OTFC was readily accepted and provided significant (dose dependent) reductions in preoperative activity starting after 30 min. Onset of sedation was related to dose of OTFC but time to peak effect was not. Vital signs remained unchanged preoperatively in all groups but patients receiving 20-25 micrograms.kg-1 had oxygen saturations that were significantly lower than patients in the other groups 30 min after beginning OTFC consumption. Three of the 12 patients receiving the highest dose of OTFC experienced transient oxygen saturation less than 90% which, however, was easily treated by commands to take a breath. Anesthetic inductions were rated good or excellent in 80% of the patients and recovery times were similar irrespective of the OTFC dose. OTFC caused dose-independent preoperative pruritus in 90% or more of patients and pruritus (33%-70%), nausea (30%-58%), and vomiting (50%-83%) postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1989

The effects of oral transmucosal fentanyl citrate premedication on preoperative behavioral responses and gastric volume and acidity in children.

The authors compared the safety, efficacy, and effects on gastric volume and pH of oral transmucosal fentanyl citrate (OTFC) premedication and of placebo lollipop and no premedication in 55 children undergoing elective operations. The patients were randomly assigned to receive no premedication (group A, N = 18); OTFC containing 15-20 micrograms/kg of fentanyl citrate (group B, N = 18); or a placebo lollipop (group C, N = 19). Activity (sedation) and anxiety scores, vital signs (including systolic and diastolic arterial blood pressures, heart and respiratory rates), and pulse oximetry determined oxygen saturation were measured before and at 10-min intervals after premedication until the patients were taken to the operating room. Gastric contents were aspirated via an orogastric tube and analyzed for volume and pH after induction of anesthesia. Quality of induction and recovery were evaluated using scoring schedules; recovery times were measured and side effects recorded. OTFC was readily accepted and provided levels of sedation and anxiolysis significantly greater after 10 min than after no premedication or the placebo lollipop. Arterial blood pressures, heart rate, and oxygen saturations were not different among the three groups. In patients given OTFC, respiratory rates were significantly lower after 10 min than they were in patients having no premedication.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1988

Functional residual capacity as a noninvasive indicator of optimal positive end-expiratory pressure.

We hypothesized that functional residual capacity (FRC) could be used as a noninvasive indicator of "optimal" positive end-expiratory pressure (PEEP), the level of PEEP that results in venous admixture below 15% with an inspired oxygen fraction less than 0.5. We compared several variables for PEEP optimization--oxygen transport, total respiratory system compliance, FRC-based compliance, mixed venous oxygen saturation, end-tidal to arterial carbon dioxide tension difference, and arterial oxygen saturation--by producing four different PEEP levels, 0, 5, 10 and 15 cm H2O, in 24 mongrel dogs in which pulmonary injury was produced. The data were regressed versus PEEP by using analysis of variance for regression. Venous admixture (F1,23 = 149.3; P less than 0.0001), end-tidal to arterial carbon dioxide tension difference (F1,23 = 64.9; P less than 0.0001), and oxygen transport (F1,23 = 95.1; P less than 0.0001) decreased linearly with PEEP. FRC (F1,23 = 248.1; P less than 0.0001) and arterial oxygen saturation (F1,23 = 66.9; P less than 0.0001) increased linearly with PEEP. Total respiratory system compliance (F1,23 = 66.6; P less than 0.0001) and mixed venous oxygen saturation (F1,23 = 12.2; P less than 0.002) had a quadratic relationship with respect to PEEP with a peak at 5 cm H2O. FRC-based compliance did not have a significant relationship to PEEP. The maximum values of total respiratory system compliance, FRC-based compliance, mixed venous oxygen saturation, and oxygen transport did not occur at PEEP levels that corresponded to a venous admixture below 15% ("optimal" PEEP).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1988

Preservation of the ischemic canine myocardium: a comparison of hypothermia, lidoflazine, and ketanserin.

The purpose of this study was to determine whether ketanserin protects the globally ischemic canine heart and whether such protection, if present, is independent of that provided by hypothermia or calcium channel blockade with lidoflazine. Forty mongrel dogs, anesthetized with halothane, were divided into eight groups of five and subjected to one hour of global myocardial ischemia during hypothermic (30 degrees C; groups 1 to 4) or normothermic (37 degrees C; groups 5 to 8) cardiopulmonary bypass (CPB). Dogs in groups 1 and 5 served as controls with respect to prebypass myocardial protective therapy, and received only placebo (a normal saline bolus) prior to CPB. Before bypass, dogs in groups 2 and 6 received lidoflazine, 1.25 mg/kg intravenously (IV); those in groups 3 and 7 received ketanserin, 5 mg IV bolus, followed by a continuous infusion at 33 microg/min during bypass. Animals in groups 4 and 8 were given both lidoflazine and ketanserin according to the dosing schedules above. No type of pharmacologic or mechanical cardiovascular support was provided after termination of CPB. Postbypass hemodynamic performance and survival of the unsupported animal were assumed to reflect the degree of myocardial protection during CPB. One minute after bypass, mean arterial pressure and cardiac output were decreased in all groups. Cardiac output was lower in groups 5 to 8 (normothermic CPB) than in groups 1 to 4 (hypothermic CPB). After CPB, left ventricular filling pressures were elevated in all groups kept normothermic and in group 3 (hypothermic CPB plus ketanserin). By 15 minutes after CPB, there were no survivors in groups 5, 7, and 8. Sixty percent of animals in group 6 (normothermic CPB plus lidoflazine) survived to the end of the study. Relative odds of survival were increased 110-fold by hypothermia and sevenfold by lidoflazine. Conversely, treatment with ketanserin was associated with an increased likelihood of nonsurvival. It is concluded that, at the doses studied, ketanserin does not protect the canine myocardium against ischemic injury and may exert a detrimental effect when combined with calcium channel blockade in this setting.

Animals↗

PubMed1988

Computer-controlled positive end-expiratory pressure titration for effective oxygenation without frequent blood gases.

We have previously designed a computerized system to automatically deliver PEEP to maintain functional residual capacity (FRC) at a desired value. The purpose of this study was to compare the computerized PEEP titration system with a standard clinical PEEP titration algorithm in the animal adult respiratory distress syndrome (ARDS) model. Thirty mongrel dogs were anesthetized, paralyzed, intubated, and ventilated. An acute pulmonary injury was produced using 0.09 ml/kg of oleic acid. The animals were then given PEEP for 5 h. Arterial and venous blood gases, BP, thermodilution cardiac output, heart rate, body temperature, total respiratory system compliance (Ctr), and end-tidal CO2 were measured every 30 min. FRC was measured using an automated sulfur hexafluoride washout system every 15 min. The animals were allocated randomly to three ten-animal groups. The first group had PEEP titrated using a standard clinical protocol; the remaining two groups had PEEP updated at 15-min intervals under computer control to maintain FRC at 1.4 times the postanesthetized, postparalyzed, preinjury value. The second group received fixed 3-cm H2O PEEP steps. The third group had variable size PEEP steps depending on the output of a proportional, integral, and derivative (PID) controller. PaCO2 was maintained at 35.8 +/- 3.4 (SD) torr. There was a significant difference in PEEP delivered between the three groups (p = .0006) and in FRC (p = .005). There was no significant difference in PaO2 (p = .80) or venous admixture (Qva/Qt) (p = .84) between the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Fentanyl pretreatment modifies anaesthetic induction with etomidate.

Haemodynamic changes and side-effects of induction of anaesthesia with etomidate were evaluated in 60 ASA Class I or II patients. The objective was to find an optimal pre-induction dose of fentanyl which eliminated haemodynamic changes and side-effects during induction and intubation without introducing other problems. Patients were randomly assigned to four groups according to the pretreatment dose of fentanyl (Group I = 2 ml normal saline; Group II = 100 micrograms of fentanyl; Group III = 250 micrograms of fentanyl; Group IV = 500 micrograms of fentanyl) administered intravenously five minutes prior to induction of anaesthesia with etomidate, 0.3 mg/kg. There was an increasing incidence of apnoea (53, 87, 87 and 100% in Groups I-IV respectively) and a decreasing incidence of myoclonus (60, 33, 13 and 0% in Groups I-IV respectively) and injection pain (53, 13, 7 and 0% in Groups I-IV respectively), P less than 0.002 chi-square test for linear trends, with increasing fentanyl dosage. The incidences of postoperative nausea and vomiting were similar in the four groups. There were also significant linear regression relationships (P less than 0.01 ANOVA for linear regression) between increasing doses of fentanyl administered before etomidate and the prevention of increases in systolic blood pressure and heart rate during the induction-intubation sequence. The data demonstrate that increasing pre-induction doses of fentanyl are more effective at minimising side-effects and preventing increases in systolic arterial blood pressure and heart rate but also increase the incidence of apnoea during induction. The results suggest that 500 micrograms of fentanyl is an ideal pretreatment dose in fit patients prior to anaesthetic induction with etomidate.

Adult↗

PubMed1987

Automated measurement of functional residual capacity by sulfur hexafluoride washout.

We have constructed a computerized, totally automated system for measuring functional residual capacity (FRC) during mechanical ventilation, at any positive end-expiratory pressure (PEEP) and fraction of inspired oxygen. This system uses washout of a small amount (0.5 to 1.0%) of an insoluble, nontoxic tracer gas, sulfur hexafluoride, to measure FRC. It requires no modification of the ventilator and only minimal changes in the breathing circuit; it can be programmed to make measurements routinely without manual intervention. The system was evaluated with three tests. The prototype sulfur hexafluoride analyzer characteristic curve was determined, and the analyzer was evaluated to determine carbon dioxide interference. A comparison with nitrogen washout FRC measurements was made in an extensive bench test with a Plexiglas lung model. The bench test was designed to determine the effects of changing gas composition and minute volume. A study was done in six healthy dogs to determine reproducibility of the FRC measurements at four PEEP levels (0, 5, 10, and 15 cm H2O: two repetitions in each animal). The sulfur hexafluoride analyzer was well characterized by an exponential equation with a multiple r2 = 0.996. The analyzer was not affected by the presence of carbon dioxide (paired t test, t19 = 1.23, P greater than 0.10). The bench test indicated that FRC (measured) = 0.969 X FRC (true) - 5.3 ml. (Multiple r2 = 0.979.) This was significantly better than the nitrogen washout system, whose regression equation was also a function of minute volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Controlled hypotension with sodium nitroprusside: anesthesiologist versus computer.

Computer systems developed for the automatic control of blood pressure have been previously shown to induce hypotension with sodium nitroprusside more rapidly and accurately than can be done with manual control. We compared the performance of a computer controller with performances by 10 anesthesiologists during challenges to homeostasis similar (or analogous) to those occurring during a surgical procedure. Hypotension was induced in 10 mongrel dogs and maintained for 2 hours, either by an anesthesiologist or by the computer controller. Challenges to homeostasis were given during the 2-hour period. The computer brought the mean arterial pressure to the desired value in an average of 4.1 minutes compared with 6.3 minutes for the anesthesiologists, but this difference was not statistically significant. There was no statistically significant difference between the computer and the anesthesiologists for 25 performance criteria. The anesthesiologists performed better during two imposed hypertensive perturbations by turning off the sodium nitroprusside sooner when the pressure rapidly decreased. In general, the computer controller performed as well as experienced anesthesiologists who devoted full attention to the control of blood pressure.

Anesthesiology↗

PubMed1987

A comparison of computer-controlled versus manual administration of vecuronium in humans.

The short elimination half-life of vecuronium suggests it may be delivered more efficiently by continuous infusion than by traditional bolus injections. The objective of this study was to compare manual administration with computer-controlled administration. Anesthesia was induced in 22 patients (American Society of Anesthesiologists [ASA] physical status I and II) with fentanyl and sodium thiopental and maintained with halothane and nitrous oxide in oxygen. Neuromuscular function was assessed at the hypothenar eminence and the adductor pollicis (train-of-four stimulation). A bolus of 0.1 mg/kg of vecuronium was given to obtain 100% twitch depression for tracheal intubation. After twitch height returned to 25% of control, relaxation was maintained by traditional bolus injections (group 1, n = 7), manually controlled continuous infusion (group 2, n = 7), or computer-controlled continuous infusion (group 3, n = 8). In all three groups the desired level of relaxation was 90% twitch depression. Variability of relaxation differed significantly among the three groups (group 1: 10.5%, group 2: 12.4%, group 3: 7.1%). Twitch height was more constant with computer control than with either bolus injections or manual infusion (P less than 0.05). There was no statistically significant difference in the drug requirement (group 1: 1.60 microgram/kg/min, group 2: 1.51 microgram/kg/min, group 3: 1.45 microgram/kg/min). Variability in the mechanomyogram (n = 12) was much higher than in the electromyogram (n = 10). Computer-controlled infusion may be a useful adjunct for the anesthesiologist who desires a stable level of patient relaxation when using short-acting, non-depolarizing relaxants.

Adolescent↗

PubMed1987

Induction of anesthesia with fentanyl or fentanyl plus etomidate in high-risk patients.

Anesthetic doses of fentanyl (46 +/- 1.3 micrograms/kg) and oxygen (group I) were compared to a moderate dose of fentanyl (3 to 4.7 micrograms/kg; mean = 3.54 +/- 0.1 micrograms/kg) + etomidate (0.4 mg/kg) intravenously (IV) (group II) during the anesthetic induction-endotracheal intubation sequence to evaluate hemodynamic changes and the incidence of side effects in 23 New York Heart Association class III and IV patients. Chest wall rigidity only occurred in group I (27%), and pain on injection (8%) and myoclonus (25%) only in group II. Patients in group I experienced transient, small increases in central venous pressure (immediately after induction) and mean pulmonary artery pressure (after tracheal intubation). Patients in group II had small, transient decreases in heart rate, mean arterial blood pressure and cardiac index after induction which returned to baseline levels immediately after tracheal intubation. The data indicate that a modest dose of fentanyl with etomidate is similar to a large (anesthetic) dose of fentanyl in terms of avoiding cardiovascular depression and preventing hemodynamic stimulation during and following the induction-tracheal intubation sequence. Our findings also demonstrate that these doses of fentanyl before etomidate decrease but do not eliminate side effects of etomidate. The results suggest that a modest dose of fentanyl followed by etomidate may be an attractive alternative to high doses of fentanyl in patients with limited cardiovascular reserve, especially when prolonged postoperative respiratory depression secondary to high doses of an opioid is undesirable.

Adult↗

PubMed1987

Comparison of sufentanil-N2O and fentanyl-N2O in patients without cardiac disease undergoing general surgery.

Sufentanil (mean total dose 2 micrograms/kg) was compared with fentanyl (mean total dose 15 micrograms/kg) as a supplement to 60% N2O anesthesia in 30 adult patients undergoing general surgical procedures. Comparisons were made with respect to stability of hemodynamic variables (heart rate and systolic and diastolic blood pressure), changes in stress hormones (cortisol, antidiuretic hormone, epinephrine, norepinephrine, and dopamine), recovery of alertness and orientation, time to extubation, postoperative analgesia, and measures of respiratory depression (resting end-tidal carbon dioxide tension [PETCO2], CO2 response curve for minute ventilation [delta VE/delta PETCO2]). Hemodynamic variables remained stable and similar in both groups throughout the study. Plasma hormone levels remained similar to baseline in both groups until 1 h postoperatively when epinephrine levels were significantly elevated in both groups (P less than 0.05). Recovery times, including time to extubation, were similar in both groups. Patients given sufentanil had less pain 30 min postoperatively than those given fentanyl, although at 60 min postoperatively pain levels were similar in both groups. Small but significant elevations in resting PETCO2 were seen in both groups postoperatively (P less than 0.05), but postoperative delta VE/delta PETCO2 responses were significantly depressed only in patients receiving fentanyl (P less than 0.05). The results of this study demonstrate that sufentanil-N2O anesthesia is as effective as fentanyl-N2O in attenuating the hemodynamic and hormonal responses to the stress of general surgery. Because continuous intraoperative PETCO2 monitoring was not employed in this study, intraoperative hypocapnea cannot be strictly excluded as a possible influence on the postoperative measures of ventilatory drive.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗