Supplemental oxygen reduces serotonin levels in plasma and platelets during colorectal surgery and reduces postoperative nausea and vomiting.

BACKGROUND AND OBJECTIVE: it has been shown that supplemental oxygen reduces the incidence of postoperative nausea and vomiting (PONV) in patients undergoing colon surgery. Serotonin is a potent trigger of PONV. Theoretically, supplemental oxygen decreases gut ischaemia during surgery and in this way minimizes the release of serotonin. We investigated the release of serotonin during and after colorectal surgery with normal and supplemental oxygen administration. METHODS: patients (n = 53) undergoing colon surgery were randomly assigned to one of two intraoperative ventilation regimens: group A (n = 30) received 80% oxygen and 20% nitrogen mixed with desflurane and group B (n = 23) received 30% oxygen and 70% nitrogen mixed with desflurane. To verify oxygenation status, we measured the arterial oxygen partial pressure (pO2) by blood gas analysis and the intramuscular tissue oxygenation using a polarographic microoxygen sensor (Licox, GMS, Mielkendorf, Germany). Serotonin levels in plasma and in platelets were measured using high-performance liquid chromatography (HPLC) before the beginning of surgery (T0), at the end of surgery (T1), and 2 h (T2), 8 h (T3) and 24 h (T4) postoperatively. PONV was assessed in the early (0-4 h) and overall (0-24 h) postoperative period by an anaesthesiologist unaware of patients' treatment regime. RESULTS: at T1, T2 and T3, serotonin levels were significantly (T1 '80% group' 80 ± 68.2 vs. '30% group' 147 ± 130.5; T2 '80% group' 78.4 ± 61 vs. '30% group' 139 ± 103; T3 '80% group' 76.2 ± 49.5 vs. '30% group' 124 ± 73.7; P < 0.05) reduced in the '80% oxygen group'. Patients in the '80% group' showed a significantly higher pO2 and subcutaneous tissue oxygenation (ptO2). The overall incidence of PONV was significantly reduced in the '80% oxygen group' ('80% group' 7% vs. '30% group' 35%). CONCLUSION: an inspired oxygen fraction of 0.8 reduces serotonin levels significantly and decreases PONV significantly in patients undergoing colon surgery.

Motility disorders in the ICU: recent therapeutic options and clinical practice.

PURPOSE OF REVIEW: Motility disturbances often occur in critically ill patients resulting in an increased rate of morbidity and mortality. Only limited options for treatment of gastrointestinal dysfunction have been introduced. Factors contributing to motility disorders in the ICU patient, and recent therapeutic approaches are reviewed in the following. RECENT FINDINGS: Despite the growing use of early enteral nutrition in the ICU and improvements in patients' outcome, feed intolerance and motility disorders in critical illness remain unsolved. Evaluation of pathophysiological patterns such as antro-pyloric dysfunction has led to a better knowledge of gut function, whereas development of new prokinetic agents is scarce, and enthusiasm has been cut by the withdrawal of some propulsive agents from the market. SUMMARY: The complexity of gastrointestinal motor function poses a challenge to the pharmacological modulation of gut motility. There has been progress in the understanding of pathophysiologic patterns, whereas therapeutic options are still rare. Metoclopramide and erythromycin are the best evaluated and still the most promising prokinetic agents. Only a few studies in critical illness are available, and the definite value of novel propulsive agents such as motilin agonists and mu-receptor antagonists is unclear due to small patient populations. The most reasonable approach of motility disorders in critical illness seems to be an individual assessment of all associated risk factors combined with early enteral nutrition and use of prokinetic agents.

Renal integrity in sevoflurane sedation in the intensive care unit with the anesthetic-conserving device: a comparison with intravenous propofol sedation.

BACKGROUND: Increased inorganic fluoride levels after methoxyflurane exposure in the 1970s and prolonged intraoperative sevoflurane use have been suggested to be potentially nephrotoxic. In the intensive care unit we evaluated the effect on renal integrity of short-term inhaled postoperative sedation with sevoflurane using the Anesthetic Conserving Device (ACD) compared with propofol. METHODS: In this prospective, randomized, single-blinded study, after major abdominal, vascular or thoracic surgery 125 patients were allocated to receive either sevoflurane (n = 64) via the ACD (end-tidal 0.5-1 vol%) or i.v. propofol (n = 61) for postoperative sedation up to 24 h. Urinary alpha-glutathione-s-transferase as primary outcome variable, urinary N-acetyl-glucosaminidase, serum creatinine, and inorganic fluoride concentrations, urine output and fluid management were measured preoperatively, at the end of surgery, and at 24 and 48 h postoperatively. RESULTS: The sedation time in the intensive care unit was comparable between the sevoflurane (9.2 +/- 4.3 h) and the propofol (9.3 +/- 4.7 h) group. Alpha-glutathione-s-transferase levels were significantly increased at 24 and 48 h postoperatively compared with preoperative values in both groups, without significant differences between the groups. N-acetyl-glucosaminidase and serum creatinine remained unchanged in both study groups, and urine output and creatinine clearance were comparable between the groups throughout the study period. Inorganic fluoride levels increased significantly (P < 0.001) at 24 h after sevoflurane exposure (39 +/- 25 micromol/L) compared with propofol (3 +/- 6 micromol/L) and remained elevated 48 h later (33 +/- 26 vs 3 +/- 5 micromol/L). One patient in each group suffered from renal insufficiency, requiring intensive diuretic therapy, but not dialysis, during hospital stay. CONCLUSIONS: Short-term sedation with either sevoflurane using ACD or propofol did not negatively affect renal function postoperatively. Although inorganic fluoride levels were elevated after sevoflurane exposure, glomerular and tubular renal integrity were preserved throughout the hospital stay.

Hepatocellular integrity after parenteral nutrition: comparison of a fish-oil-containing lipid emulsion with an olive-soybean oil-based lipid emulsion.

BACKGROUND AND OBJECTIVE: Parenteral nutrition including lipids might be associated with liver disease. The cause leading to parenteral nutrition-related liver dysfunction remains largely unknown but is likely to be multifactorial. The study was performed to assess the effects of a lipid emulsion based on soybean oil, medium-chain triglycerides, olive and fish oil (SMOFlipid20%) compared with a lipid emulsion based on olive and soybean oil on hepatic integrity. METHODS: In a prospective, randomized, double-blinded trial, 44 postoperative patients with an indication for parenteral nutrition were allocated to one of two regimens: group A (n = 22) received SMOFlipid, group B (n = 22) a lipid emulsion based on olive and soybean oil for 5 days. Aspartate aminotransferase, alanin-aminotransferase, and serum alpha-glutathion S-transferase were measured before the start of parenteral nutrition (d0), at day 2 (d2), and day 5 (d5) after the start of parenteral nutrition. The significance level was defined at a P value of less than 0.05. RESULTS: There was no significant difference at d0, but at d2 and d5, significantly lower aspartate aminotransferase (d2: group A: 27 +/- 13 vs. group B: 47 +/- 36 U l(-1); d5: A: 31 +/- 14 vs. B: 56 +/- 45 U l(-1)), alanin-aminotransferase (d2: A: 20 +/- 12 vs. B: 42 +/- 39 U l(-1); d5: A: 26 +/- 15 vs. B: 49 +/- 44 U l(-1)), and alpha-glutathion S-transferase levels (d2: A: 5 +/- 6 vs. B: 17 +/- 21 U l(-1); d5: A: 6 +/- 7 vs. B: 24 +/- 27 microg l(-1)) were found in soybean oil, medium-chain triglycerides, olive and fish oil group compared with the control group. CONCLUSION: Hepatic integrity was well retained with the administration of SMOFlipid whereas in patients receiving a lipid emulsion based on olive and soybean oil liver enzymes were elevated indicating a lower liver tolerability.

Short-term sevoflurane sedation using the Anaesthetic Conserving Device after cardiothoracic surgery.

OBJECTIVE: We evaluated the procedure of postoperative inhalational sedation with sevoflurane using the Anaesthetic Conserving Device (ACD) with regard to recovery times, feasibility and consumption of anaesthetics in comparison to propofol. DESIGN AND SETTING: Prospective, randomised, single-blinded, controlled study in a surgical intensive care unit (ICU) of a 1,000-bed academic hospital. PATIENTS AND INTERVENTIONS: A total of 70 patients after elective coronary artery bypass graft surgery either received sevoflurane via ACD (n = 35) or propofol (n = 35) for short-term postoperative sedation in the ICU. MEASUREMENTS AND MAIN RESULTS: The primary endpoint was extubation time from termination of sedation. Recovery times, consumption of anaesthetics, endtidal sevoflurane concentrations, length of ICU and hospital stay, and side effects were documented. Mean recovery times were significantly shorter with sevoflurane than with propofol (extubation time: 22 vs. 151 min; following commands: 7 vs. 42 min). The mean (SD) sevoflurane consumption was 3.2 +/- 1.4 mL/h to obtain mean endtidal concentrations of 0.76 vol%. No serious complications occurred during sedation with either sedative drug. The length of ICU stay was comparable in both groups, but hospital length of stay was significantly shorter in the sevoflurane group. Drug costs (in Euro) for sedation per patient were similar in both groups (sevoflurane: 15.1 +/- 9.5 ; propofol: 12.5 +/- 5.8 ), while sevoflurane sedation costs that included use of the ACD were significantly higher. CONCLUSIONS: Sevoflurane administration via ACD is an effective and safe alternative to propofol to provide postoperative short-term ICU sedation. Recovery from sedation was facilitated with sevoflurane instead of propofol and resulted in shorter extubation and ventilator times. DESCRIPTOR: Neurology/sedation, Sedation and anaesthesia.

The influence of aprotinin and tranexamic acid on platelet function and postoperative blood loss in cardiac surgery.

BACKGROUND: Antifibrinolytic drugs including aprotinin and tranexamic acid are currently used in cardiac surgery to reduce postoperative bleeding and transfusion requirements, and may have different effects on platelets. We therefore evaluated platelet function after cardiopulmonary bypass (CPB) and cardiac surgery to determine the effect of either aprotinin or tranexamic acid. METHODS: In a prospective, randomized study, 50 patients scheduled for elective cardiac surgery with CPB were evaluated. Patients received high-dose aprotinin (n = 25) or tranexamic acid (n = 25) as antifibrinolytic drugs. Coagulation and platelet function were assessed preoperatively, after CPB, 3 and 24 h after surgery using modified thrombelastography and whole blood aggregometry. RESULTS: Impaired coagulation after CPB occurred in both groups compared with preoperative data (P < 0.01). In contrast to modified thrombelastography, thrombin receptor-mediated aggregometry after CPB was significantly decreased only in those patients receiving tranexamic acid until the end of the study period in comparison to the aprotinin group (P < 0.05). Aprotinin-treated patients showed significantly less chest tube drainage (575 mL +/- 228 vs 1033 mL +/- 647, P < 0.05) and need for postoperative transfusion requirements (P < 0.01) compared with the tranexamic acid group. CONCLUSIONS: Platelet function measured by whole blood aggregometry is better preserved by aprotinin than tranexamic acid and may be responsible for producing less bleeding within the first 24 h after CPB.

Postoperative analgosedation with S(+)-ketamine decreases the incidences of postanesthetic shivering and nausea and vomiting after cardiac surgery.

BACKGROUND: Along with postoperative nausea and vomiting (PONV), postanesthetic shivering (PAS) is one of the leading causes of distress postoperatively. Previous studies report on a decrease in incidence of PAS due to ketamine administration; however, the S(+) isomer of ketamine has not been evaluated before. Additionally the administration of ketamine minimizes the use of opioids, one of the most important risk factor of PONV. The aim of the present study was to evaluate the efficacy of S(+)-ketamine in the prophylaxis of both PAS and PONV in patients undergoing cardiac surgery. MATERIAL/METHODS: After ethics committee approval and written informed consent from the patients, 54 patients scheduled for coronary artery bypass graft surgery (CABG) were studied for both postanesthetic shivering and PONV. The sedation on the ICU was maintained using continuous infusion of propofol (1-3 mg x kg(-1) x h(-1)) and if necessary boli of 3.75 mg piritramide. At arrival in the ICU patients supplementary received either S(+)-ketamine (2 mg x kg(-1) x h(-1); group A; n=27) or 0.9% saline as placebo (group B; n=27) in a double-blind fashion. The severity of PAS was assessed by using a five-point rating scale. Fifteen minutes after extubation and 24 hours postoperatively, patients were asked about occurrence of PONV. RESULTS: In group A 4 (14.8%) patients suffered from PAS compared to 12 (44.4%) in the control group (p<0.05). The severity of shivering was significantly lower in group A than in group B (p<0.05). In group A, patients showed a significant lower incidence of PONV (3.7% vs. 33.3%) and vomiting (3.7% vs. 22.2%) compared to patients of group B (p<0.05). CONCLUSIONS: S(+)-ketamine reduced both postanesthetic shivering and postoperative nausea and vomiting, when administered for postoperative analgosedation.

Evaluation of a new platelet function analyzer in cardiac surgery: a comparison of modified thromboelastography and whole-blood aggregometry.

OBJECTIVES: Impaired hemostasis of multiple etiologies are often present in patients undergoing cardiopulmonary bypass (CPB) surgery. Platelet dysfunction is considered to be important in the early postoperative period. Therefore, a new whole-blood platelet function analyzer was compared with thromboelastography in predicting postoperative hemostatic outcomes as measured by blood loss and blood product use. DESIGN: Prospective study. SETTING: Teaching hospital. PARTICIPANTS: The study enrolled 54 patients scheduled for coronary artery bypass surgery with CPB. INTERVENTIONS: Coagulation and platelet function were assessed preoperatively, after CPB, at 3 hours, and at 24 hours after surgery by using thromboelastography and impedance aggregometry. Patients were divided into a transfused and nontransfused group on the basis of postoperative transfusion requirements. Postoperative blood loss and requirements of blood transfusions were documented until 24 hours postoperatively. MEASUREMENTS AND MAIN RESULTS: Twenty-five patients (46%) received postoperative blood transfusions. Impaired hemostasis occurred after CPB detected by thromboelastography (p < 0.01) and impedance aggregometry (p < 0.01). In contrast to thromboelastography, preoperative adenosine diphosphate-mediated aggregometry correlated with postoperative requirements for blood transfusion (Spearman r = -0.302, p < 0.05) and was significantly lower in patients receiving allogeneic blood transfusion compared with nontransfused patients (p < 0.05). Neither aggregometry nor thromboelastography was correlated with postoperative blood loss. CONCLUSION: Impedance aggregometry as well as thromboelastography are able to detect impaired hemostasis after CPB. In contrast to thromboelastography, aggregometry using a new whole-blood aggregometer identified patients with a reduced risk for postoperative transfusion requirements.

Postoperative nausea and vomiting after surgery for prognathism: not only a question of patients' comfort. A placebo-controlled comparison of dolasetron and droperidol.

INTRODUCTION: The aim of this study was to evaluate the efficacy of dolasetron and droperidol (DHB) for preventing postoperative nausea and vomiting (PONV) in patients undergoing surgery for prognathism. MATERIAL AND METHODS: In a randomised, placebo-controlled, double-blind trial, the efficacy of 12.5 mg dolasetron i.v. and 1.25 mg DHB was evaluated in preventing PONV in 83 patients undergoing surgery for prognathism. Patients were allocated randomly to one of three groups: group A (n=27) received 12.5 mg dolasetron intravenously (i.v.), group B (n=27) received 1.25 mg DHB i.v. and placebo group C (n=29) received saline 0.9%. If patients complained of retching or vomiting or if patients demanded antiemetics, 20mg metoclopramide (MCP) i.v. was given. Postoperative nausea, postoperative vomiting, or nausea and vomiting was assessed in the postoperative period at 0-4 h and overall between 0 and 24 h. RESULTS: A significant reduction in the incidence of postoperative nausea and/or vomiting was observed in the dolasetron group (33%) when compared with DHB (81%) and placebo (86%) treated patients. No other significant differences between the DHB and the placebo group were found. Dolasetron (11%) significantly reduced vomiting in comparison with the DHB (52%) and placebo group (52%). The use of postoperative MCP per patient was significantly lower in the dolasetron group when compared with both other groups. Dolasetron significantly reduced the postoperative nausea and/or vomiting-score when compared with both other groups. There was no significant difference between DHB- and placebo-treated patients with regard to nausea and/or vomiting. CONCLUSION: Intravenous dolasetron (12.5 mg) is more effective than either intravenous DHB (1.25 mg) or placebo for preventing PONV after surgery for prognathism. It also was significantly superior to either DHB or placebo concerning nausea and vomiting and the need for MCP rescue medication.

Noninvasive assessment of cardiac output using thoracic electrical bioimpedance in hemodynamically stable and unstable patients after cardiac surgery: a comparison with pulmonary artery thermodilution.

OBJECTIVE: To compare noninvasive cardiac output (CO)measurement obtained with a new thoracic electrical bioimpedance (TEB) device, using a proprietary modification of the impedance equation, with invasive measurement obtained via pulmonary artery thermodilution. DESIGN: Prospective, observational study. SETTING: Surgical intensive care unit (ICU) of a university-affiliated community hospital. PATIENTS AND PARTICIPANTS: Seventy-four adult patients undergoing elective cardiac surgery with routine pulmonary artery catheter placement. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Simultaneous paired CO and cardiac index (CI) measurements by TEB and thermodilution were obtained in mechanically ventilated patients upon admission to the ICU. For analysis of CI data the patients were subdivided into a hemodynamically stable group and a hemodynamically unstable group. The groups were analyzed using linear regression and tests of bias and precision. We found a significant correlation between thermodilution and TEB (r = 0.83; n < 0.001), accompanied by a bias of -0.01 l/min/m(2) and a precision of +/-0.57 l/min/m(2) for all CI data pairs. Correlation, bias, and precision were not influenced by stratification of the data. The correlation coefficient, bias, and precision for CI were 0.86 (n< 0.001), 0.03 l/min/m(2), and +/-0.47 l/min/m(2) in hemodynamically stable patients and 0.79 (n< 0.001), 0.06 l/min/m(2), and +/-0.68 l/min/m(2) in hemodynamically unstable patients. CONCLUSIONS: Our results demonstrate a close correlation and clinically acceptable agreement and precision between CO measurements obtained with impedance cardiography using a new algorithm to calculate CO from variations in TEB, and those obtained with the clinical standard of care, pulmonary artery thermodilution, in hemodynamically stable and unstable patients after cardiac surgery.

Influence of prolonged cardiopulmonary bypass times on splanchnic perfusion and markers of splanchnic organ function.

BACKGROUND: Cardiopulmonary bypass (CPB) is known to have considerable negative impact on perfusion and organ function. The effects of the duration of CPB on markers of splanchnic organ function was studied. METHODS: Consecutive patients undergoing elective aorto-coronary bypass grafting with CPB times (CPBT) of either less than 70 minutes (n = 15) or more than 80 minutes (n = 15) were prospectively studied. Splanchnic perfusion was assessed by measuring arterial and gastric mucosal PCO2 and calculating PCO2gap. Hepatic function was evaluated by monoethylglycinexylidide (MEGX) test and by measuring alpha-glutathione S-transferase (alpha-GST). Concentration of pancreatitis-associated protein was measured to assess pancreatic integrity. Measurements were performed after induction of anesthesia, at the end of surgery, 4 hours after arrival in the intensive care unit, and on postoperative day 1. RESULTS: The mean (+/- standard deviation) CPBT were 54 +/- 12 minutes and 99 +/- 16 minutes, respectively. PCO2gap increased significantly more in the group with CPBT of more than 80 minutes than in that with CPBT of less than 70 minutes, at +15 +/- 4 mm Hg versus +8 +/- 3 mm Hg, respectively, indicating reduction in splanchnic perfusion by longer CPBTs. Postoperative MEGX concentrations were significantly lower and postoperative alpha-GST concentrations were significantly higher in the group with CPBT of more than 80 minutes than in that with CPBT of less than 70 minutes. Plasma levels of pancreatitis-associated protein remained similar in both groups throughout the study period. CONCLUSIONS: In our patients with CPBT of more than 80 minutes, splanchnic perfusion and hepatocelluar integrity were moderately affected, whereas pancreatic function remained almost unchanged. Studies including a larger patient population are necessary to assess whether protective approaches would be helpful in patients undergoing complex cardiac surgery with very long CPBT.

Total intravenous anesthesia with propofol and remifentanil is associated with a nearly twofold higher incidence in postanesthetic shivering than desflurane-fentanyl anesthesia.

BACKGROUND: Postanesthetic shivering (PAS) is a frequent side effect of general anesthesia. Previous reports on the incidence of PAS of propofol for the induction or maintenance of anesthesia have been controversial, but have not been studied in detail. The aim of the present study was to evaluate the incidence and severity of PAS in total intravenous anesthesia (TIVA) with propofol and remifentanil compared with an inhalative anesthesia. MATERIAL/METHODS: After ethics committee approval and written informed consent from the patients, 53 patients scheduled for urologic, gynecologic, or surgical operations were studied for shivering postoperatively using a five-point rating scale. They received desflurane-fentanyl based anesthesia (n=27) or TIVA with propofol and remifentanil (n=26). Hemodynamics and temperature were measured after induction of anesthesia (T0), and 5 min (T1), 15 min (T2), 30 min (T3), and 60 min (T4) after reaching the postanesthetic care unit (PACU). RESULTS: In the TIVA group, 18/26 (69.2%) patients suffered from PAS compared with 10/27 (37%) in the desflurane-fentanyl group (P<0.02). The severity of shivering was significantly higher with TIVA than with desflurane (P<0.02), whereas temperature showed no significant difference between the study groups. CONCLUSIONS: Postanesthetic shivering appears significantly more frequently and intensively after TIVA with propofol and remifentanil compared with an inhalative anesthesia with fentanyl and desflurane.

Continuous intra- and postoperative thoracic epidural analgesia attenuates brain natriuretic peptide release after major abdominal surgery.

We investigated whether blocking afferent nociceptive inputs by continuous intra- and postoperative thoracic epidural analgesia (TEA) would decrease plasma concentrations of brain natriuretic peptide (BNP) in patients who were at risk for, or had, coronary artery disease. Twenty-eight patients undergoing major abdominal surgery received either general anesthesia supplemented with a continuous thoracic epidural infusion of 1.25 mg/mL bupivacaine and 1 microg/mL sufentanil (n = 14; TEA) or general anesthesia followed by IV patient-controlled analgesia (n = 14; IV PCA). Visual analog scale pain scores, hemodynamics, plasma catecholamines, cardiac troponin T, atrial natriuretic peptide (ANP), and BNP were serially measured preoperatively, 90 min after skin incision, at arrival in the intensive care unit, and in the morning of the first, second, and third postoperative day. Dynamic visual analog scale scores were significantly less in the TEA group. TEA reduced the postoperative heart rate without affecting other hemodynamic variables. Plasma epinephrine increased perioperatively in both groups but was significantly lower in the TEA group. Baseline ANP and BNP concentrations were similar between groups (TEA 3.4 +/- 1.8 and 27.0 +/- 12.3 pg/mL; IV PCA 3.1 +/- 2.0 and 25.9 +/- 13.0 pg/mL, respectively). ANP and BNP increased perioperatively in both groups, with significantly lower postoperative BNP levels in TEA patients (TEA 92.1 +/- 31.9 pg/mL; IV PCA 161.2 +/- 44.7 pg/mL). No such difference was observed in plasma ANP concentrations. Plasma cardiac troponin T concentrations were within normal limits in both groups at all times. We conclude that continuous perioperative TEA using local anesthetics and opioids attenuated the release of BNP in patients undergoing major abdominal surgery who were at risk for, or had, coronary artery disease.

The heart in the elderly critically ill patient.

Cardiac complications such as myocardial infarction and congestive heart failure are the primary source of perioperative morbidity and mortality in elderly surgical patients. This is the result of structural and functional age-related changes in the heart and the vasculature and an increasing incidence of cardiovascular disorders. Appropriate perioperative management of the elderly patient should be based on the extent of functional compromise, the type and severity of pre-existing disease, and the invasiveness of the surgical procedure. Current studies suggest that appropriately administered medical therapy, particularly beta-adrenergic blockade, may reduce perioperative cardiovascular morbidity and mortality in these patients. In this article, we review changes in cardiovascular structure and function that occur with advancing age and describe perioperative medical interventions that may improve cardiac outcome in the elderly critically ill patient.

Dolasetron, but not metoclopramide prevents nausea and vomiting in patients undergoing laparoscopic cholecystectomy.

PURPOSE: Postoperative nausea and vomiting (PONV) is one of the most frequent complications of general anesthesia. The aim of the study was to compare the antiemetic efficacy of dolasetron and metoclopramide after inhalational or i.v. anesthesia (IVA). METHODS: In a randomized, placebo-controlled, double-blinded trial we evaluated the efficacy of 12.5 mg dolasetron i.v. and 20 mg metoclopramide (MCP) i.v. in preventing PONV in 387 patients (ASA I-III) undergoing laparoscopic cholecystectomy. Patients were allocated randomly to one of three main groups: Group D (n = 129) received 12.5 mg dolasetron i.v., Group MCP (n = 129) 20 mg MCP i.v., and Group C (n = 129) saline as placebo i.v. Using a multifactorial study design, one third of each main group (n = 43) was further randomized to receive either general anesthesia with desflurane, isoflurane or IVA with propofol and remifentanil. PONV, postoperative piritramide and droperidol consumption were documented. RESULTS: Independent from the anesthesia regimen chosen, dolasetron reduced PONV (19%) significantly compared to MCP (45%) and placebo (46%). Furthermore we could show a significant difference in the incidence of PONV between IVA (28%) and isoflurane (46%), but not in comparison to desflurane (36%). Patients receiving IVA had a higher postoperative piritramide consumption compared to the two other groups. CONCLUSIONS: The results of our study suggest that dolasetron was more effective than MCP and placebo in preventing PONV. This action is independent of the anesthetic technique used.

Dolasetron for preventing postanesthetic shivering.

UNLABELLED: We designed this study to assess the efficacy of dolasetron compared with clonidine and placebo in prophylaxis of postanesthetic shivering. We included 90 patients undergoing elective abdominal or urologic surgery. The patients were randomly assigned to one three groups (each group n = 30) using a double-blinded study protocol: Group A received 12.5 mg dolasetron, Group B 3 microg/kg clonidine, and Group C saline 0.9% as placebo. The medication was given after the induction of anesthesia. Postanesthetic shivering was judged by using a five-point scale. In the Clonidine group, 86.6% showed no shivering, whereas in the Dolasetron and Placebo groups, only 63.3% and 66.6%, respectively, were symptom free. Only clonidine, but not dolasetron, significantly reduced the incidence and the severity of shivering. We conclude that clonidine is effective in preventing shivering when given before surgery, whereas dolasetron, at the dose used, is not effective. IMPLICATIONS: Shivering, an irregular muscular fasciculation lasting longer than 15 s, is a common complication secondary to general anesthesia. We compared dolasetron with clonidine (an established antishivering drug) in the prevention of postanesthetic shivering. Dolasetron 12.5 mg was not effective.

The influence of allogeneic red blood cell transfusion compared with 100% oxygen ventilation on systemic oxygen transport and skeletal muscle oxygen tension after cardiac surgery.

In this study we investigated the effects of allogeneic red blood cell (RBC) transfusion on tissue oxygenation compared with those of 100% oxygen ventilation by using systemic oxygen transport variables and skeletal muscle oxygen tension (PtiO2). Fifty-one volume-resuscitated, mechanically ventilated patients with a nadir hemoglobin concentration in the range from 7.5 to 8.5 g/dL after elective coronary artery bypass grafting were allocated randomly to receive 1 unit (transfusion 1; n = 17) or 2 units (transfusion 2; n = 17) of allogeneic RBCs and ventilation with 40% oxygen or pure oxygen ventilation (100% oxygen; n = 17) and no allogeneic blood for 3 hours. Invasive arterial and pulmonary artery pressures and calculations of oxygen delivery (oxygen delivery index) and consumption indices (oxygen consumption index) were documented at 30-min intervals. PtiO2 was measured continuously by using implantable polarographic microprobes. Systemic oxygen transport variables and PtiO2 were similar between groups at baseline. The oxygen delivery index increased significantly with transfusion of allogeneic RBCs and 100% oxygen ventilation, whereas the oxygen consumption index remained unchanged. Oxygen 100% ventilation increased PtiO2 significantly (from 24.0 +/- 5.1 mm Hg to 34.2 +/- 6.2 mm Hg), whereas no change was found after transfusion of allogeneic RBCs. Peak PtiO2 values were 25.2 +/- 5.2 mm Hg and 26.3 +/- 6.5 mm Hg in the transfusion 1 and 2 groups, respectively. Transfusion of stored allogeneic RBCs was effective only in improving systemic oxygen delivery index, whereas 100% oxygen ventilation improved systemic oxygen transport and PtiO2. This improved oxygenation status was most likely due to an increase in convective oxygen transport with a large driving gradient for diffusion of plasma-dissolved oxygen into the tissue.

The influence of hyperoxic ventilation during sodium nitroprusside-induced hypotension on skeletal muscle tissue oxygen tension.

BACKGROUND: Increasing inspired oxygen concentrations might provide a simple and effective intervention to increase oxygen tension in tissues during controlled hypotension. To test this hypothesis, the influence of hyperoxic ventilation (100% O2) on skeletal muscle oxygen partial pressure (Ptio2) in patients receiving sodium nitroprusside-induced controlled hypotension was studied. METHODS: Forty-two patients undergoing radical prostatectomy were prospectively studied and randomly divided into three groups as follows: (1) Controlled hypotension induced by sodium nitroprusside (mean arterial blood pressure, 50 mmHg) and hyperoxic ventilation (CH-100%; n = 14); (2) controlled hypotension and ventilation with 50% O2 in nitrous oxide (CH-50%; n = 14); and (3) standard normotensive anesthesia with 50% O2 in nitrous oxide (control; n = 14). Ptio2 values were measured continuously in all patients using implantable polarographic microprobes. Arterial blood gases and lactate concentrations were analyzed in 30-min intervals. RESULTS: Surgical blood loss and transfusion requirements were significantly reduced in both groups receiving hypotensive anesthesia. During surgery, arterial partial pressure of oxy-gen and arterial oxygen content were significantly higher in patients of the CH-100% group. Baseline values of Ptio2 were comparable between the groups (CH-50%: 25.0 +/- 0.7 mmHg; CH-100%: 25.2 +/- 0.2 mmHg; control: 24.5 +/- 0.2 mmHg). After a transient increase in Ptio2 in the CH-100% group during normotension, Ptio2 values returned to baseline and remained unchanged in the control group. Ptio2 decreased significantly during the hypotensive period in the CH-50% group. The lowest mean Ptio2 values were 15.0 +/- 4.1 mmHg in the CH-50% group, 24.2 +/- 4.9 mmHg in the CH-100% group, and 23.5 +/- 3.8 mmHg in the control group. There were no significant changes in lactate plasma concentrations in any group throughout the study period. CONCLUSIONS: Hyperoxic ventilation improved skeletal muscle tissue oxygenation during sodium nitroprusside-induced hypotension. This improved local tissue oxygenation seems to be most likely due to an increase in convective oxygen transport and the attenuation of hyperoxemia-induced arteriolar vasoconstriction by sodium nitroprusside.