Intraoperative catecholamine release in brain-dead organ donors is not suppressed by administration of fentanyl.

BACKGROUND AND OBJECTIVE: Endogenous catecholamines are released in brain-dead organ donors following painful stimulation during retrieval surgery, and might be harmful to harvested organs. Our hypothesis was that inhibition of pain by fentanyl would inhibit such catecholamine release. METHODS: We tested 17 brain-dead organ donors in a randomized, placebo-controlled, double-blinded study. Blood samples for determination of epinephrine and norepinephrine concentrations were obtained before and 10 min after in take of either fentanyl 7 microg kg(-1) or an equivalent volume of placebo. Further points of measurement were taken after skin incision and sternotomy. Mean arterial pressure and heart rate at these points were recorded. RESULTS: Catecholamine concentrations rose following painful stimuli. No differences in haemodynamics, between the fentanyl and the placebo group were detectable. Epinephrine concentrations, but not those of norepinephrine, were higher in the fentanyl group, reaching significance following sternotomy. CONCLUSION: We conclude that the use of fentanyl (7 microg kg(-1)) was not effective in suppressing the catecholamine release, following painful surgical stimulation in brain-dead organ donors.

Recollection of dreams after short general anaesthesia: influence on patient anxiety and satisfaction.

BACKGROUND AND OBJECTIVE: We ascertained whether dreams during short general anaesthesia influence subsequent patient satisfaction and anxiety. METHODS: Fifty female patients were randomized into two groups to test for a difference between intravenous and inhalational anaesthesias. In Group Propo, anaesthesia was induced and maintained with propofol; in Group Metho-Iso, anaesthesia was induced with methohexital and maintained with isoflurane. Satisfaction and anxiety with anaesthesia were evaluated using a visual analogue scale from 0 to 100. Dream incidence rate, satisfaction and anxiety were assessed from immediately after waking until 3 months later. RESULTS: Seventeen patients (34%) dreamed during anaesthesia. There were no significant differences in satisfaction or anxiety after anaesthesia between the dreaming and non-dreaming patients (satisfaction, 92.3 +/- 21.6 versus 92.1 +/- 21.6; anxiety, 21.1 +/- 21.1 versus 30.3 +/- 32.1), or between Group Propo and Group Metho-Iso (satisfaction, 94.4 +/- 19.3 versus 90.0 +/- 23.4; anxiety, 26.0 +/- 27.6 versus 28.4 +/- 30.7). There was no significant difference in the incidence rate of dreaming with the type of anaesthesia used (Group Propo, 11 patients; Group Metho-Iso, 6 patients). CONCLUSIONS: Dreaming during general anaesthesia is common but does not influence satisfaction or anxiety after anaesthesia.

Comparable postoperative pulmonary atelectasis in patients given 30% or 80% oxygen during and 2 hours after colon resection.

BACKGROUND: High concentrations of inspired oxygen are associated with pulmonary atelectasis but also provide recognized advantages. Consequently, the appropriate inspired oxygen concentration for general surgical use remains controversial. The authors tested the hypothesis that atelectasis and pulmonary dysfunction on the first postoperative day are comparable in patients given 30% or 80% perioperative oxygen. METHODS: Thirty patients aged 18-65 yr were anesthetized with isoflurane and randomly assigned to 30% or 80% oxygen during and for 2 h after colon resection. Chest radiographs and pulmonary function tests (forced vital capacity and forced expiratory volume) were obtained preoperatively and on the first postoperative day. Arterial blood gas measurements were obtained intraoperatively, after 2 h of recovery, and on the first postoperative day. Computed tomography scans of the chest were also obtained on the first postoperative day. RESULTS: Postoperative pulmonary mechanical function was significantly reduced compared with preoperative values, but there was no difference between the groups at either time. Arterial gas partial pressures and the alveolar-arterial oxygen difference were also comparable in the two groups. All preoperative chest radiographs were normal. Postoperative radiographs showed atelectasis in 36% of the patients in the 30%-oxygen group and in 44% of those in the 80%-oxygen group. Relatively small amounts of pulmonary atelectasis (expressed as a percentage of total lung volume) were observed on the computed tomography scans, and the percentages (mean +/- SD) did not differ significantly in the patients given 30% oxygen (2.5% +/- 3.2%) or 80% oxygen (3.0% +/- 1.8%). These data provided a 99% chance of detecting a 2% difference in atelectasis volume at an alpha level of 0.05. CONCLUSIONS: Lung volumes, the incidence and severity of atelectasis, and alveolar gas exchange were comparable in patients given 30% and 80% perioperative oxygen. The authors conclude that administration of 80% oxygen in the perioperative period does not worsen lung function. Therefore, patients who may benefit from generous oxygen partial pressures should not be denied supplemental perioperative oxygen for fear of causing atelectasis.

Postoperative pain and subcutaneous oxygen tension.

Surgical patients randomly assigned to standard pain control had postoperative subcutaneous oxygen partial pressures that were significantly less than patients given better pain treatment. Our data suggest that control of postoperative pain is a major determinant of surgical-wound infection and should be given the same consideration as maintaining adequate vascular volume and normothermia.

[Neostigmine and edrophonium. Antagonism of profound and shallow mivacurium blockade]. / Neostigmin und Edrophonium. Antagonisierung einer tiefen und oberflächlichen Mivacuriumblockade.

UNLABELLED: Mivacurium has a short duration of action because it is rapidly hydrolysed by plasma cholinesterase. There is ongoing controversy concerning the antagonism of mivacurium-induced neuromuscular block, firstly because of its short spontaneous recovery time, and secondly because the metabolism of mivacurium may be inhibited by anticholinesterases. We therefore compared neostigmine and edrophonium reversal of deep and moderate mivacurium-induced blocks. METHODS: After approval by the local ethics committee, 48 ASA class I and II adult patients were investigated during nitrous oxide-fentanyl-thiopental anaesthesia using train-of-four (TOF) stimulation and monitoring of the isometric force of adduction of a thumb. The patients received 0.2 mg/kg mivacurium i.v. Neuromuscular transmission was allowed to recover spontaneously in 10 patients (group SP). In 2 other groups the neuromuscular block was antagonised by administration of 0.04 mg/kg neostigmine (group N5; n = 9) or 1.0 mg/kg edrophonium (group E5; n = 10) when T1 had recovered spontaneously to 5% of control. In two other groups the neuromuscular block was antagonised with the same doses of neostigmine or edrophonium in 10 patients (group N25) and 9 patients (group E25), respectively, when T1 had recovered spontaneously to 25% of control. RESULTS: Neostigmine or edrophonium administered when T1 had recovered spontaneously to 25% of control shortened the recovery time (time from administration of ant-agonist to a T4/T1-ratio of 0.7) significantly from 10.7 +/- 2.2 min (mean +/- SD) in the SP group to 5.1 +/- 2.0 and 5.3 +/- 1.5 min in the N25 and E25 groups, respectively (P < 0.05). The corresponding recovery times in the SP, N5, and E5 groups were 15.9 +/- 2.9, 10.0 +/- 1.9, and 7.7 +/- 2.2 min, respectively. The difference between the SP and E5 groups was significant (P < 0.05). The recovery indices (time from 25% to 75% recovery of T1) of 3.0 +/- 1.3 and 1.7 +/- 0.9 min for the E5 and E25 groups, respectively, were shorter than those of the SP group at 6.1 +/- 2.0 min (P < 0.05). CONCLUSIONS: Two theoretical reasons, the very rapid onset time and the fact that it does not inhibit plasma cholinesterase, suggest edrophonium to be the preferred antagonist of a mivacurium-induced blockade. These two characteristics are reflected in our results: only edrophonium was able to shorten the recovery index significantly and, administered at a profound level of mivacurium-induced neuromuscular block, only edrophonium was successful in shortening recovery time significantly. Therefore, edrophonium should be the anticholinesterase of choice to antagonise a mivacurium-induced neuromuscular block.

Influence of prostaglandin E1 on tissue ischemia during surgical repair of the abdominal aorta.

OBJECTIVE: To evaluate tissue protection by PGE1 during leg ischemia in patients undergoing aortic surgery. DESIGN: Randomized, controlled prospective clinical trial. SETTING: Single university hospital. PARTICIPANTS: 19 consecutive patients undergoing abdominal aortic aneurysm repair. INTERVENTIONS: Patients received infusions of 30 ng/kg/min of PGE1 or saline. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variables, lactate, creatine phosphokinase, and thromboxane B2 (TXB2) were measured. In the control group, the decrease in cardiac index (CI) after aortic cross-clamping (AXC) persisted until unclamping together with a decrease in femoral venous O2 content (CfvO2). In the PGE1 group, CI returned to baseline with a trend toward greater CfvO2 levels. During reperfusion in the PGE1 group, O2 consumption and lactate levels exceeded preclamp values. Pulmonary hypertension occurred equally in both groups but did not correlate with TXB2, which was not altered by surgery or by PGE1 infusion. CONCLUSIONS: Intraoperative PGE1 treatment offers no benefit and may exacerbate tissue ischemia during AXC by redistributing microcirculatory flow or limiting cellular oxygen utilization in a manner that overwhelms any possible protective effect.

Endocrine stress reaction to surgery in brain-dead organ donors.

We studied the course of plasma levels of the stress markers adrenocorticotropic hormone (ACTH), cortisol, human growth hormone (h-GH), beta-endorphin, and prolactin during retrieval surgery in eleven brain-dead organ donors scheduled for multiple organ explantation. Donors were divided into two groups according to hemodynamic stability. Hormones demonstrated a great variability in plasma levels and in the pattern of reaction, revealing a different degree of remaining pituitary function. Beta-Endorphin was the only stress hormone that showed a response to surgical stimuli in six patients. Only three of them developed a concomitant rise in ACTH. Cortisol, prolactin, and h-GH plasma levels did not change during the observation period. In the three cases with a slight elevation in ACTH, no subsequent change in cortisol was detectable. Beta-Endorphin showed greater variability and a tendency to higher levels in the group presenting with a higher arterial pressure, which resulted in a significant difference (P < 0.005) when distributions were compared using the Mann-Whitney U-test. No correlation was found between hypotensive episodes and deficiencies of other stress hormones. We conclude that pituitary function varies considerably in brain-dead organ donors without demonstrating a correlation to the onset of hypotension. Thus, we feel no need for a substitution treatment with any of the hormones investigated prior to organ explanation.

Cardiovascular and catecholamine response to surgery in brain-dead organ donors.

Eleven brain-dead organ donors were studied during surgery. Plasma levels of adrenaline and noradrenaline were measured before and after skin incision, upon sternotomy and 15, 30 and 45 min thereafter. Haemodynamic changes were measured continuously throughout the observation period. Blood pressure and heart rate increased after skin incision, remained high at sternotomy then decreased towards the end of the observation period in six of the 11 patients. Plasma catecholamines increased promptly with the onset of surgical stimuli. We conclude that surgical stress can evoke an excessive rise of plasma adrenaline and noradrenaline and thus could impair allograft function.

[Preoperative autologous blood donation, effect of hydroxyethyl starch on the reticuloendothelial system and opsonins]. / Präoperative Eigenblutspende, der Einfluss von Hydroxyäthylstärke auf Retikuloendothelialsystem und Opsonine.

The effect of 6% low molecular weight (LMW) HES (MW 270,000) on reticuloendothelial function was studied in 9 male patients, median of age 50 years, who were scheduled for vascular surgery. An erythrocyte clearance test (Anti Rh) labeled with 99 mTc, evaluating primarily the splenic section of the RES, showed a considerable variation (37-87%) prior to hemodilution. 24 hours after replacement of 15 ml/kg body weight of blood, there was no significant change of the clearance rate, a follow up weeks later approached the base line values. Plasma opsonins like fibronectin, complement fraction 3, complement fraction 4 and immunoglobulin G showed a proportional decrease following hemodilution, and after 24 hours approached control levels. Changes at this time seemed to be independent from the course of the hematocrit. It is concluded that LMW HES does not adversely influence the spleen dependent phagocytic capacity of the RES system.

The effect of isovolaemic haemodilution on infection-related serum protein levels.

Approximately 25% of blood was replaced by either hydroxyethyl starch (mol. wt 450,000), dextran (mol. wt 60,000), or 5% plasma protein solution, 24 h prior to a surgical intervention. Twenty-four adult patients were studied and haematocrit, total protein, plasma albumin, alpha-1-antitrypsin, IgG, IgM, antithrombin III, fibronectin and alpha-2-macroglobulin were determined. The resulting blood concentrations suggest that the various replacement solutions exert only a dilutional effect upon the proteins studied. Furthermore, there is no difference regarding the course of the various infection-related proteins whether plasma protein solution or synthetic colloids are used for blood replacement. The decrease of the studied proteins during the study period does not exceed 35% of the control value. This is not considered to be a clinically significant reduction and levels of infection-related proteins were not dangerously low.