Respiratory gas exchange during total body hyperthermia in man

Respiratory gas exchange was evaluated using indirect calorimetry during total body hyperthermia (TBH) in 7 postoperative patients with disseminated gastric cancer to the peritoneal cavity. TBH was induced using veno-venous bypass and extracorporeal circuit incorporating a heat exchanger to keep pulmonary arterial temperature 42 degrees C. The high temperature was maintained for 3 hours under general anesthesia with droperidol (0.15 mg.kg-1), morphine (1 mg.kg-1) and enflurane (less than 0.5%). Oxygen consumption (VO2) was also calculated using the Fick equation and thermodilution cardiac output. Hyperthermia for three hours increased both VO2 and carbon dioxide output (VCO2) values to 1.5 times as compared to the control values before heating, respectively. VO2 values measured by indirect calorimetry correlated well with the values calculated from the Fick equation when respiratory and cardiovascular system were relatively stable during the procedure. Gradual but statistically insignificant increase in respiratory quotient was observed after recooling started. These results suggest that indirect calorimetry was valuable to measure respiratory gas exchange continuously during hyperthermic state as well as normothermic state. However, RQ value observed in the present study may be modified by several factors including lactate accumulation in the blood, and may not reflect substrate utilization during the hyperthermic state.     

Hemodynamic effects of infusions of alpha-human atrial natriuretic peptide in anesthetized dogs]

The purpose of this study is to investigate and compare the hemodynamic effects of infusion of alpha-human atrial natriuretic peptide (alpha-hANP) at three different doses. Mongrel dogs were anesthetized with 0.87% halothane in oxygen. alpha-hANP was infused for one hour with a constant rate at either 0.3, 1.0, or 10.0 micrograms.kg-1.min-1, respectively. They were randomly divided into four groups. Group A-1 received 0.3 micrograms.kg-1.min-1 of alpha-hANP; Group A-2 received 1.0 micrograms.kg-1.min-1 of alpha-hANP; Group A-3 received 10.0 micrograms.kg-1.min-1 of alpha-hANP; and Group C received normal saline as the vehicle and served as the control. Control values were obtained before infusion of alpha-hANP or vehicle was started, and hemodynamic variables were measured at 30 minutes intervals for two hours. Mean arterial pressure (MAP) of the group C showed no significant changes from control value. During and after infusion of alpha-hANP, MAP in the group A-2 and A-3 was significantly lower than the control values. The decrease in MAP of the group A-2 was the greatest. Heart rate decreased significantly at 60 minutes after termination of the infusion in all four groups. The reduction of cardiac index (CI) in the group-3 was the greatest. In the group A-3, it decreased for 31% from the control value at 60 minutes during infusion. However, this change was not significant. In contrast, the reduction in CI of the group A-2 was minimal. Mean pulmonary artery pressure (MPAP) of the group C showed no significant change from the control value. The patterns of changes in MPAP were similar to those of the alpha-hANP infused groups. It decreased progressively during the infusion. Systemic vascular resistance (SVR) was essentially unchanged in the group C. In the group A-2, SVR decreased slightly during the infusion period and then tended to increase after the infusion of alpha-hANP. In contrast, in the group A-1 and A-3, SVR increased progressively. The changes in left ventricular maximum dp/dt (LV dp/dt max) of the group C were minimal. The reduction in LV dp/dt max was more pronounced in group A-2 than in group A-3. In conclusion, our data show that hypotensive effects of alpha-hANP are associated with the reduction in cardiac output due to the decrease of cardiac contractility. However, the changes of hemodynamic variable are not dose-dependent.     

The effects of preemptive intravenous versus preemptive epidural morphine on postoperative analgesia and surgical stress response after orthopaedic procedures

BACKGROUND: The purpose of this study was to evaluate the effect of pre-emptive intravenous versus pre-emptive epidural morphine on both postoperative analgesic consumption and surgical stress response. METHODS: Sixty patients, ASA I or II, aged 18-85, undergoing total hip or knee replacement were randomly assigned to three groups of 20 patients. In group pre-emptive epidural, patients were administered an epidural injection of 75 micrograms.kg-1 morphine about 45 minute before dermal incision. In group pre-emptive intravenous, patients were administered 0.15 mg.kg-1 of intravenous morphine following induction before dermal incision. In group control, patients were administered intravenous saline following induction before dermal incision. RESULTS: The pre-i.v. group used significantly less morphine than the pre-epi group (p < 0.0003). In all groups, plasma cortisol levels increased as compared to pre-op values, but plasma cortisol increased more significantly in the pre-i.v. and control groups within 4 hrs of surgery and was still significantly elevated at 7 am of the first postoperative morning compared to the pre-epi group (p < 0.001) and the increase persisted to the next morning in patients pre-i.v. and control groups. CONCLUSIONS: Although pre-emptive epidural morphine has failed to decrease postoperative analgesic consumption, it has been able to suppress the surgical stress more significantly than intravenous morphine and a saline control.     

The hemodynamic effects of methylene blue when administered at the onset of cardiopulmonary bypass

Hypotension occurs during cardiopulmonary bypass (CPB), in part because of induction of the inflammatory response, for which nitric oxide and guanylate cyclase play a central role. In this study we examined the hemodynamic effects of methylene blue (MB), an inhibitor of guanylate cyclase, administered during cardiopulmonary bypass (CPB) to patients taking angiotensin-converting enzyme inhibitors. Thirty patients undergoing cardiac surgery were randomized to receive either MB (3 mg/kg) or saline (S) after institution of CPB and cardioplegic arrest. CPB was managed similarly for all study patients. Hemodynamic data were assessed before, during, and after CPB. The use of vasopressors was recorded. All study patients experienced a similar reduction in mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) with the onset of CPB and cardioplegic arrest. MB increased MAP and SVR and this effect lasted for 40 minutes. The saline group demonstrated a persistently reduced MAP and SVR throughout CPB. The saline group received phenylephrine more frequently during CPB, and more norepinephrine after CPB to maintain a desirable MAP. The MB group recorded significantly lower serum lactate levels despite equal or greater MAP and SVR. In conclusion, administration of MB after institution of CPB for patients taking angiotensin-converting enzyme inhibitors increased MAP and SVR and reduced the need for vasopressors. Furthermore, serum lactate levels were lower in MB patients, suggesting more favorable tissue perfusion.     

Ibuprofen pretreatment inhibits prostacyclin release during abdominal exploration in aortic surgery

Mesenteric traction during aortic surgery produces facial flushing, reduced mean arterial pressure (MAP), and systemic vascular resistance (SVR) with increased heart rate (HR) and cardiac index (CI). Elevated 6-keto-prostaglandin-F1 alpha (6-keto-PGF1 alpha) suggests prostacyclin is the mediator. To test this hypothesis, the cyclooxygenase inhibitor, ibuprofen (n = 14), or placebo (n = 13) was administered to patients electively scheduled for aortic reconstruction. The hemodynamic measurements and plasma concentrations of prostanoids between groups were compared immediately before (0), and 5, 10, 15, 30, and 45 min following mesenteric traction. Following mesenteric traction significant differences (P less than 0.05) were observed between the ibuprofen pretreatment and placebo group over time in SVR, MAP, HR, CI, 6-keto-PGF1 alpha, and thromboxane B2 (TXB2). Significant differences between groups at individual times were found in SVR, HR, CI, 6-keto-PGF1 alpha, and TXB2. In the placebo group flushing was accompanied by reduced SVR and MAP and increased HR and CI. The greatest effect was seen at 10 min and resolved over 30 min. Plasma concentration of 6-keto-PGF1 alpha increased from 159 +/- 103 (mean +/- SEM) pg/ml to a peak value of 3,765 +/- 803 at 10 min. A late increase in TXB2 occurred with a peak value of 1,970 +/- 891 (mean +/- SEM) pg/ml at 30 min. In the ibuprofen pretreated group no significant changes occurred in hemodynamic measurements or concentrations of prostanoids. The inhibition of 6-keto-PGF1 alpha and its associated hemodynamic changes in the treatment group, but not in the placebo group, confirms the hypothesis that prostacyclin is the mediator of the mesenteric traction response in abdominal aortic surgery.     

Dopamine may preserve the myocardial oxygen balance better than dobutamine when administered with milrinone

PURPOSE: To compare the hemodynamic effects of dopamine with those of dobutamine when administered with milrinone in patients undergoing non-cardiac surgery. METHODS: In 14 patients undergoing major surgery during anesthesia with isoflurane, milrinone (50 microgram*kg(-1) followed by 0.25 microgram*kg(-1)*min(-1)) was administered. Hemodynamic baseline values were assessed 50 min after continuous infusion of milrinone. Additional infusion of either dopamine or dobutamine, randomly selected, was started at the rate of 4 and later 8 microgram*kg(-1)*min(-1); each hemodynamic variable was measured 20 min after changing the infusion rate. One hour after ceasing the infusion of one catecholamine (dopamine or dobutamine), the other was infused at the rate of 4 and 8 microgram*kg(-1)*min(-1). RESULTS: Milrinone increased heart rate (HR), but decreased mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P < 0.05 for each). Dopamine administered with milrinone significantly increased MAP and cardiac output (CO), whereas dobutamine significantly increased HR and CO, but decreased SVR. By comparison between dopamine and dobutamine administered at the rate of 8 microgram*kg(-1)*min(-1), there was a significant difference in HR, MAP, and SVR (P < 0.01, 0.01, and 0.05, respectively). CONCLUSION: Dopamine and dobutamine administered with milrinone induce different hemodynamic changes: dopamine increases MAP without affecting HR, whereas dobutamine increases HR. Our data suggest that the myocardial oxygen balance might be better preserved with dopamine than with dobutamine when administered with milrinone.     

Drug interactions with sufentanil. Hemodynamic effects of premedication and muscle relaxants.

Induction of anesthesia with synthetic opioids is occasionally accompanied by undesirable hemodynamic changes such as tachycardia and hypertension, or bradycardia and hypotension. We hypothesized that drug interactions cause many of these adverse responses. Therefore, we conducted a randomized double-blind study to investigate the interactive effect of premedication and muscle relaxants on the hemodynamic response to induction with intravenous (iv) sufentanil 10 micrograms.kg-1. Eighty patients with left ventricular ejection fraction greater than or equal to 0.40, undergoing elective coronary artery surgery, were premedicated with either morphine 0.1 mg.kg-1 and scopolamine 6 micrograms.kg-1 intramuscularly, or lorazepam 60 micrograms.kg-1 orally, and paralyzed with either pancuronium 0.1 mg.kg-1 or vecuronium 0.1 mg.kg-1 iv. The four treatment groups were SP (morphine-scopolamine + pancuronium), LP (lorazepam + pancuronium), SV (morphine-scopolamine + vecuronium), and LV (lorazepam + vecuronium). Hemodynamics were recorded at three time periods: 1) control, 2) induction, and 3) intubation. Premedication-relaxant interactions significantly affected hemodynamics. In group SP, mean heart rate (HR) increased significantly on induction (56 +/- 11 to 69 +/- 13 beats.min-1), while mean arterial pressure (MAP) and cardiac index (CI) were unchanged. HR, MAP, and CI were significantly higher after induction in group SP compared to the other three groups. In group LP, mean HR increased less than in group SP (56 +/- 8 to 62 +/- 14 beats.min-1), whereas MAP and CI declined significantly. In group SV, HR and CI were unchanged, but MAP declined significantly. In group LV, HR was stable, whereas both MAP and CI declined significantly. The incidence of pharmacologic interventions during the study period also differed significantly among groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Etomidate inhibits adrenocortical function in surgical patients

Postoperative adrenocortical function was compared in 23 out-patients receiving either thiopental, 4 mg/kg, for induction and a thiopental infusion, 0.26 mg . kg-1 . min-1, in combination with nitrous oxide 70% for maintenance of anesthesia (control); etomidate, 0.4 mg/kg, for induction followed by an etomidate infusion, 0.02 mg . kg-1 . min-1, and nitrous oxide 70% for maintenance (etomidate I); or etomidate, 0.4 mg/kg, for induction and a thiopental infusion, 0.22 mg . kg-1 . min-1, in combination with nitrous oxide 70% for maintenance (etomidate II). The norepinephrine response to anesthesia and surgery did not differ significantly between the three groups. The postoperative cortisol response to ACTH stimulation was normal in the control group (maximum rise in plasma cortisol was 20.1 +/- 2.9 micrograms/dl [mean +/- SEM] ), however, it was decreased in all patients receiving etomidate, whether by a short infusion (mean change in plasma cortisol was -3.8 +/- 1.9 micrograms/dl) or as a single induction dose (mean change in plasma cortisol was -4.0 +/- 2.0 micrograms/dl). Similarly, the postoperative aldosterone levels in the control group increased normally in response to ACTH (+ 10.2 +/- 3.0 ng/dl) but decreased in both the etomidate I and etomidate II groups (-3.0 +/- 0.7 ng/dl and -3.3 +/- 1.0 ng/dl, respectively). Because ACTH was administered exogenously, etomidate-induced suppression of adrenocortical response appeared to be a direct effect on the adrenal gland, which was present at a time when the serum etomidate levels were in the subhypnotic range.(ABSTRACT TRUNCATED AT 250 WORDS)     

Total intravenous anesthesia with continuous infusion of midazolam--study on plasma levels of midazolam and catecholamines

Total intravenous anesthesia was performed with continuous infusion of midazolam and bolus injection of fentanyl. A bolus injection of midazolam 0.3 mg.kg-1 was followed by an infusion regimen with an initial infusion rate of 0.68 mg.kg-1.hr-1 for 15 min followed by a maintenance infusion of 0.125 mg.kg-1.hr-1 and infusion was stopped at about 30 min before the end of operation. Fentanyl and pancuronium were injected as required. Nicardipine was given for intraoperative hypertension. Plasma concentrations of epinephrine and norepinephrine decreased significantly at 10 min after induction, but increased significantly during operation. Therefore, this anesthetic method was considered not to be so deep. Plasma concentrations of midazolam were higher than 200 ng.ml-1 during operation. After discontinuation of midazolam infusion, its concentration decreased quickly, and the elimination half life of midazolam was 1.675 +/- 0.2807 hr. The value was not so large as we had anticipated. Total intravenous anesthesia with continuous infusion of midazolam and bolus injection of fentanyl is thought to produce light anesthesia. Plasma concentration of midazolam decreased quickly.     

The effect of olprinone administered after cardio-pulmonary bypass during open heart surgery, evaluated by its plasma concentrations and hemodynamic changes]

Plasma concentrations and hemodynamic effects of olprinone were evaluated in seventeen patients undergoing open heart surgery. The patients were randomized into the bolus group (15 micrograms.kg-1 bolus dose +0.1 microgram.kg-1.min-1 infusion, n = 9) and the non-bolus group (0.1 microgram.kg-1.min-1 infusion, n = 8). Plasma concentrations and hemodynamic variables were measured before CPB (cardiopulmonary bypass; baseline), 5, 60 min after weaning from CPB, and 3, 6 hours after the end of surgery. Plasma concentrations in the non-bolus group were significantly lower than those of bolus group at any point except for 3 hours after the end of surgery. In the bolus group, increases in the cardiac index and stroke volume index were significantly higher compared with the non-bolus group. From these results we conclude that olprinone given in bolus (15 micrograms.kg-1) followed by continuous infusion (0.1 microgram.kg-1.min-1) is efficacious and safe during weaning from CPB.     

Plasma morphine levels during its continuous epidural infusion

We evaluated plasma levels of morphine during its continuous epidural infusion for postoperative analgesia in nine adult patients. A bolus injection of 3 mg of morphine was administered epidurally 3 hours prior to the proposed end of the surgery, and thereafter continuous epidural infusion of morphine was continued at a rate of 0.167-0.042 mg.hr-1 with a pump (CADD-PCA, 5200P, Pharmacia) during and after the surgery until the 3rd postoperative day. The dose of morphine was gradually decreased to 0.021-0.042 mg.hr-1 without reducing the quality of postoperative analgesia. Plasma morphine levels were measured by gas chromatography-mass spectrometry method. Plasma concentrations of morphine were 4.6 +/- 0.7 (Mean +/- SE) ng.ml-1 at the end of surgery and they decreased thereafter to 0.7 +/- 0.1 ng.ml-1, 0.3 +/- 0.1 ng.ml-1 and 0.1 +/- 0.1 ng.ml-1 on the 1st, 2nd and 3rd postoperative days, respectively. Plasma levels of morphine decreased gradually correlating with reduction of infused morphine. Adequate postoperative pain relief was obtained throughout the procedure without any severe complications such as respiratory depression. The analgesic effect of epidural morphine did not parallel with that of plasma concentration. Plasma concentrations of morphine administered by continuous epidural infusion with a pump were estimated to be lower than the minimum analgesic plasma concentration (10-40 ng.ml-1), and the toxic levels of morphine during continuous epidural infusion were not detected by our method.     

Cardiovascular effects of, and catecholamine response to, high dose fentanyl or NLA in patients for valve replacement]

We measured the cardiovascular effect of, and catecholamine and other hormonal responses to, anesthetic doses of fentanyl and original NLA in 25 patients for open heart surgery. The patients were randomly divided into three groups (group N, F30, F75). During induction, in group N; droperidol 0.25 mg.kg-1 and fentanyl 5 micrograms.kg-1, in group F30; fentanyl 30 micrograms.kg-1, and in group F75; fentanyl 75 micrograms.kg-1 were administered intravenously. Additional fentanyl was administered at a rate of 100 to 200 micrograms.h-1. Droperidol 0.25 mg.kg-1 was administered in group N when cardiopulmonary bypass (CPB) was disconnected. Plasma samples were assayed for norepinephrine, epinephrine, ACTH and cortisol before and after induction, during sternotomy, 60 minutes after institution of CPB, after weaning from CPB, and before as well as after extubation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and rate pressure product (RPP) were calculated simultaneously at the blood samplings. In all groups, no remarkable change in cardiovascular dynamics was observed. CPB was associated with marked increases in catecholamines, but high dose fentanyl in dose of 75 micrograms.kg-1 was able to suppress epinephrine level more than in group N. In high dose fentanyl group (F30, F75) ACTH was within normal ranges, even during CPB. The results suggest that high dose fentanyl is a complete anesthetic in patients for cardiac surgery. But a large dose of fentanyl causes small decreases in heart rate and arterial blood pressure. Our data indicate that group F30 is an attractive anesthetic technique for patients with valvular disease.     

Rapid induction with vecuronium/fentanyl combinations for coronary artery surgery: influence on cardiovascular responses and plasma fentanyl concentrations]

Cardiovascular effects of fentanyl (60 micrograms.kg-1.min-1)/vecuronium combination for rapid induction were studied in fifty five patients for coronary artery bypass grafts. Cardiovascular and cerebral profiles of patients who had rapid fentanyl administration (39 patients) or slow fentanyl administration (15 patients) were compared with base line values and between each group. Plasma samples were assayed for epinephrine, norepinephrine, growth hormone, anti diuretic hormone and fentanyl. There were no differences in all hemodynamic parameters between each group. However, in the rapid administration group, statistically significant changes were detected in the heart rate, cardiac index, stroke volume index and left ventricular stroke work index. The changes in the heart rate were small and returned to the baseline value after sternotomy. A decrease in cardiac index after induction depends on a decrease in stroke volume index rather than in the heart rate. In rapid administration group, the EEG showed low frequency activity within a minute. The hormonal stress responses were significantly attenuated in both groups. High plasma concentrations of fentanyl could be achieved at the intubation. The data demonstrate that rapid induction by fentanyl is safe and convenient.     

Effect of continuous epidural infusion of morphine for postoperative analgesia on pituitary-adrenocortical function

Plasma levels of cortisol, ACTH and beta-endorphin like immunoreactivity (beta-ELI) were measured to evaluate postoperative pain relief with epidural morphine and systemic analgesics in conjunction with endocrine functions in 16 patients who underwent gastrectomy. Eight of these patients (epidural morphine group) obtained postoperative analgesia with continuous epidural infusion of morphine with a pump as in our previous report. A bolus of epidural morphine was administered through an indwelling thoracic (Th8,9) catheter at 3 hrs prior to the proposed end of the surgery, which was followed with continuous epidural infusion of morphine at a rate of 0.167-0.042 mg.hr-1 with a pump (CADD-PCA, Model 5200P, Pharmacia) during and after anesthesia and surgery with gradual decrease in dose until the third postoperative day. The remaining eight patients (systemic analgesics group) repeatedly received systemic pentazocine and buprenorphine when needed. Plasma cortisol levels increased significantly at the end of surgery and after in both groups. However plasma concentrations of cortisol in the epidural morphine group were significantly lower than those in the systemic analgesics group on the first and second postoperative days. Plasma levels of ACTH and beta-ELI increased significantly at the end of surgery but returned to levels of the previous day in both groups postoperatively. Our study suggests that continuous epidural infusion of morphine is adequate for postoperative pain relief and has suppressing effect on plasma cortisol levels as compared with systemic analgesics regimen.     

Changes in systemic circulation under induced total spinal block and choice of vasopressors

Total spinal block by using 2% lidocaine 0.5 ml.kg-1 (10.0 mg.kg-1) was carried out in adult mongrel dogs. The effects of atropine 0.02 mg.kg-1, isoproterenol 0.5 mcg.kg-1, methoxamine 0.1 mg.kg-1 and ephedrine 0.5 mg.kg-1 to counteract circulatory changes by total spinal block were studied. Atropine did not exert any marked influence on circulatory system. Isoproterenol elevated HR, LV dp/dt max and CI temporarily, but did not decrease MAP and SVR. Methoxamine elevated MAP and SVR, but decreased CI. Ephedrine is a drug of choice for this situation because it elevated HR, MAP, LV dp/dt max and SVR.     

Fentanyl and sufentanil anesthesia revisited: how much is enough?

This study was undertaken to determine if fentanyl and sufentanil could produce dose-related suppression of hemodynamic and hormonal responses to surgical stimulation. Eighty patients scheduled for elective CABG were studied in two consecutive protocols: protocol I was a randomized double-blind study of 40 patients who received a single dose of fentanyl (50 or 100 micrograms/kg) or sufentanil (10, 20, or 30 micrograms/kg). Hemodynamic measurements and hormonal concentrations (renin, aldosterone, cortisol, and catecholamines) were determined before and after induction and after intubation and sternotomy. Protocol II was an open randomized study of 40 patients who received sufentanil in one of four doses: 30 micrograms/kg as a single dose, 10 micrograms/kg plus infusion 0.05 microgram.kg-1.min-1, 20 micrograms/kg plus infusion 0.1 microgram.kg-1.min-1, or 40 micrograms/kg plus infusion 0.2 microgram.kg-1.min-1. Hemodynamic measurements and plasma sufentanil and catecholamine concentrations were determined before and after induction and after intubation, sternotomy, and aortic cannulation. Both protocols defined a hemodynamic response as a 15% or more increase in systolic blood pressure (SBP) from control and a hormonal response 50% or more increase over control. During protocol I, 18 patients had a hemodynamic response (average increase in SBP 22.6 +/- 2%) and 35 patients had a total of 59 hormonal responses. During protocol II, 24 patients had a hemodynamic response (average increase in SBP - 31 +/- 3%) and there were 15 catecholamine responses. There were no differences between dose groups in either protocol. It was concluded that in these dose ranges, suppression of hemodynamic or hormonal stress responses is not related to opioid dose.(ABSTRACT TRUNCATED AT 250 WORDS)     

Metabolic and endocrine responses to surgery during caudal analgesia in children

Plasma concentrations of glucose, lactate, epinephrine, norepinephrine, insulin, cortisol and growth hormone were measured in 28 healthy children, three to six years of age, before, during, and after lower abdominal surgery. The children received premedication with secobarbital, 6 mg.kg-1, pentazocine, 0.5 mg.kg-1, and atropine, 0.01 mg.kg-1 im. Fourteen children received general anaesthesia with nitrous oxide and halothane, and 14 others received caudal analgesia with 1.5% mepivacaine. Plasma glucose, epinephrine and norepinephrine concentrations remained unchanged in the general anaesthesia group, but decreased during and after surgery in the caudal analgesia group (P less than 0.05). During surgery, these concentrations were different between the two groups (P less than 0.05). Plasma insulin and cortisol concentrations increased after surgery (P less than 0.05), and growth hormone concentration increased during and after surgery in the general anaesthesia group (P less than 0.05), but the concentrations of these hormones remained unchanged during and after surgery in the caudal analgesia group. Plasma lactate concentrations were unchanged in both groups. These results indicate that caudal analgesia suppresses the metabolic and endocrine responses to stress associated with lower abdominal surgery in children.     

Time course and hemodynamic effects of alpha-1-adrenergic bolus administration in anesthetized patients with myocardial disease

Phenylephrine (Phe) is frequently administered as an intravenous (IV) bolus to increase blood pressure, yet the acute time course and hemodynamic effects of bolus Phe in patients with myocardial disease have not been reported. Therefore 50 randomized IV bolus doses of Phe (50, 100, 150, or 200 micrograms) were given to 18 patients during anesthesia for elective coronary artery surgery. Esophageal Doppler techniques were used to continuously monitor cardiac output (CO); mean arterial pressure (MAP), CO, and calculated systemic vascular resistance (SVR) were recorded every 5 seconds for a total of 2 minutes. The hemodynamic changes (mean +/- SEM) for each of the four doses of Phe (50, 100, 150, 200 micrograms) were maximal at about 42 seconds after the drug was given. They consisted of an increase in MAP (11.6 +/- 2.1, 15.6 +/- 2.4, 14.7 +/- 2.4, 18.0 +/- 1.5 mm Hg); increase in SVR (766 +/- 190, 930 +/- 310, 950 +/- 344, 1732 +/- 824 dynes.sec.cm-5); and a decrease in CO (-.58 +/- .11, -.68 +/- .13, -.73 +/- .20, -.77 +/- .18 L.min-1). Hypertension, increased age, low preoperative ejection fraction, high baseline CO, and low baseline SVR significantly (P less than 0.05) decreased hemodynamic responses to Phe (see text). In conclusion, bolus IV Phe in patients with myocardial disease increases MAP and SVR and simultaneously decreases CO; these peak hemodynamic events occur approximately 42 seconds after Phe administration.     

Intraoperative mild hypothermia does not increase the plasma concentration of stress hormones during neurosurgery

PURPOSE: To determine how mild hypothermia (34 degrees C) affects the hemodynamic and the stress hormonal responses intraoperatively and during extubation in patients undergoing cerebral aneurysm surgery. METHODS: After induction, anesthesia was maintained with 1.2% isoflurane and 50% nitrous oxide. For the normothermia and the hypothermia groups, the body temperature was maintained at 36.9 +/- 0.3 degrees C and 34.2 +/- 0.2 degrees C respectively up to the recovery room. Hemodynamic changes were recorded continuously. Stress hormones comprising epinephrine, norepinephrine, ADH, ACTH, and cortisol were measured at the awake control, intraoperative, and extubation periods. RESULTS: Vital signs of the intraoperative and postextubation time periods were not significantly different between the normothermia and hypothermia groups except for a statistically lower pulse rate intraoperatively in the hypothermia group (P <0.05). In the control awake state, all five hormonal concentrations were similar between the two groups. Intraoperatively, all of the hormonal levels tended to be lower in the hypothermia group compared to the normothermia group, but only the epinephrine level decreased sufficiently to reach statistical significance (P <0.05). During extubation, all stress hormone concentrations, except norepinephrine, were lower in the hypothermia group (epinephrine: P <0.05; ADH: P <0.05; ACTH: P <0.05; cortisol: P <0.05). CONCLUSIONS: Our data suggest that intraoperative mild hypothermia neither significantly affects the blood pressure response nor increases the concentrations of stress hormones intraoperatively. Furthermore, mild hypothermia significantly decreased the plasma concentrations of stress hormones during the extubation period.     

Effects of indomethacin on endocrine responses and nitrogen loss after surgery.

In 14 patients who had elective gastrectomy, 50 mg of indomethacin was administered intrarectally every 6-8 hours after operation until postoperative day 3. Body temperature, plasma cortisol and glucagon concentrations, blood glucose level, urinary catecholamine level, and urinary nitrogen excretion level were compared with those of 16 patients who did not receive indomethacin. Postoperative fever was significantly reduced by indomethacin. Plasma cortisol levels in the indomethacin-treated group were significantly lower on postoperative days 2 and 3. Postoperative increases in plasma glucagon and blood glucose levels were not influenced by indomethacin administration. Urinary epinephrine excretion tended to be inhibited, and urinary norepinephrine excretion was significantly inhibited in the indomethacin-treated group after operation. Urinary nitrogen excretion levels during the observation period were significantly less in the indomethacin-treated group. The cumulative urinary nitrogen level from postoperative days 1-3 in the indomethacin-treated group was 82% of that in the control group. These results indicated that fever reduction by indomethacin after surgery resulted in reduced protein loss, associated with attenuated cortisol and catecholamine responses.