Impact of intraoperative blood salvage on monocyte subsets alteration and intracellular tumor necrosis factor-α production

Intraoperative salvaged blood is used to reduce allogeneic blood transfusion in orthopedic surgery patients. However, salvaged blood reinfusion may lead to immune reactions. Salvaged and venous blood from 20 patients undergoing hip arthroplasty was processed. The salvaged samples were mixed with patients' venous blood and incubated in absence or presence of lipopolysaccharide.

SAMPLES

Venous: venous patient blood (n = 20). Native: mixed salvaged native blood (n = 20). Filtered: mixed salvaged leukocyte filtered blood (n = 20). Irradiated: mixed salvaged irradiated blood (n = 20). The frequency of the surface receptors CD14, HLA-DR, and intracellular tumor necrosis factor (TNF)-α on peripheral blood mononuclear cells was analyzed by fluorescence-activated cell sorting analysis. The frequency of unstimulated CD14^low and CD14^high cells as well as unstimulated HLA-DR and TNF-α positive monocytes was comparable between venous and filtered salvaged blood. However, native and irradiated salvaged blood increased compared with venous (p < 0.05) and filtered salvaged blood (p < 0.05) for unstimulated CD14^low cells, HLA-DR, and TNF-α positive monocytes. Stimulated intracellular TNF-α positive monocytes were decreased in native, filtered, and irradiated salvaged blood compared with venous blood (p < 0.05). Processing perioperative salvaged blood with leukofiltration minimizes the influence on monocytes activation compared with native and irradiated salvaged blood. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 815-821, 2018.

Impact of intraoperatively salvaged and washed blood on stimulated cytokine release in vitro

BACKGROUND

Intraoperative blood salvage and processing it with commercially available devices is a widespread standard procedure to reduce allogeneic blood transfusion in patients undergoing major orthopedic surgery. The aim of this study was to investigate the impact of such processed blood on the immune system by measuring pro- and anti-inflammatory cytokines.

STUDY DESIGN AND METHODS

Salvaged blood from 20 patients undergoing hip arthroplasty was processed with a continuous autotransfusion system. One part of the processed blood was left without further treatment, one part was additionally leukoreduced, one part was irradiated, and one part was separated into its cellular and soluble fraction by centrifugation. Specimens from each part were mixed in vitro with venous blood from the patient in ratios of 3:1, 1:1, and 1:3 and incubated with endotoxin for 24 hours. Tumor necrosis factor (TNF)-α and interleukin (IL)-10 were measured in cell culture supernatants by enzyme-linked immunosorbent assay.

RESULTS

All parts of the salvaged blood were without a significant influence on TNF-α release. In contrast, IL-10 was significantly increased, independently of the admixtured salvaged blood being plain, additionally irradiated, or additionally leukoreduced. This IL-10 increase was also found with the cellular fraction of the plain salvaged blood, whereas the soluble fraction had no influence on IL-10 release.

CONCLUSION

Intraoperative salvaged blood is not immunologically inert. We observed a significant increase in the anti-inflammatory IL-10 response without affecting the proinflammatory TNF-α release. Neither leukofiltration nor gamma irradiation eliminated this effect that was limited only to the cellular fraction of the salvaged blood, suggesting red blood cells to be responsible for the observed immunomodulation.

[Necessity for treatment of psychiatric emergencies in the emergency medical service. Evaluation of the "indicator for psychiatric pharmacotherapy"]

BACKGROUND

Psychiatric emergency situations (PES) are common in the physician-based emergency medical system (EMS) in Germany. However, many emergency physicians (EP) feel insecure in assessing the necessity for treatment of these patients. The aim of this investigation was to evaluate whether a short, newly developed questionnaire (Indicator for Psychiatric Pharmacotherapy, IPP) is able to help EPs in deciding for or against pharmacological treatment.

PATIENTS AND METHODS

The protocols of the EMS at the Saarland University Hospital were prospectively collected over a 1-year period and PESs were identified and analyzed in detail. The 7-item IPP, which focuses on the most relevant psychiatric symptoms, was to be completed for each PES.

RESULTS

Among all calls for an EP (2,114) 250 (11.8%) were classified as a PES. The most frequent diagnoses were alcoholic intoxication, state of agitation and suicide attempts. Of the IPP questionnaires 193 could be evaluated and in 31.2% of all PESs a specific psychiatric medication was administered. These patients scored significantly higher in the IPP compared to those who did not receive medication (8.0 ± 3.9 compared to 5.6 ± 3.2, p < 0.001). The IPP items "anxiety", "agitation/aggression", "mood" and "physical symptoms/disorders" had the highest impact on the administration of psychotherapeutic drugs.

DISCUSSION

The IPP can be a valuable tool to assess the necessity of pharmacological treatment for patients in PESs. The assessment of the symptom categories "anxiety", "agitation/aggression", "mood" and "physical symptoms/disorders" seems to be sufficient to estimate a need for treatment.

Droperidol has comparable clinical efficacy against both nausea and vomiting

BACKGROUND

Droperidol is commonly noted to be more effective at preventing postoperative nausea (PON) than vomiting (POV) and it is assumed to have a short duration of action. This may be relevant for clinical decisions, especially for designing multiple-drug antiemetic regimens.

METHODS

We conducted a post hoc analysis of a large multicentre trial. Within this trial, 1734 patients underwent inhalation anaesthesia and were randomly stratified to receive several antiemetic interventions according to a factorial design, one of which was droperidol 1.25 mg vs placebo. We considered differences to be significant when: (i) point estimates of one outcome are not within the limits of the confidence interval (CI) of the other outcome; and (ii) differences in risk ratio (also known as relative risks, RR) are at least 20%.

RESULTS

Over 24 h, nausea was reduced from 42.9% in the control to 32.0% in the droperidol group, corresponding to a relative risk (RR) of 0.75 (95% CI from 0.66 to 0.84). Vomiting was reduced from 15.6% to 11.8%, and therefore associated with a similar RR of 0.76 (0.59-0.96). In the early postoperative period (0-2 h), droperidol prevented nausea and vomiting similarly, with an RR of 0.57 (0.46-0.69) for nausea and 0.56 (0.37-0.85) for vomiting. In the late postoperative period (2-24 h), the RR was again similar with 0.83 (0.72-0.96) for nausea compared with 0.89 (0.66-1.18) for vomiting but significantly less compared with the early postoperative period.

CONCLUSIONS

We conclude that droperidol prevents PON and POV equally well, yet its duration of action is short-lived.

The effect of postoperative fasting on vomiting in children and their assessment of pain

BACKGROUND

Mandatory postoperative food intake has been shown to increase nausea and vomiting, and so postoperative fasting has become common practice even if patients request food or drink.

OBJECTIVE

We sought to investigate whether postoperative fasting reduces the incidence of postoperative vomiting in children when compared with a liberal regimen in which they are allowed to eat and drink upon request.

METHODS

One hundred forty-seven children scheduled for outpatient surgery were randomized to one of two groups. After anesthesia, patients in the 'fasting' group were expected to fast for 6 h. The children in the 'liberal' group were allowed to eat and drink according to their own needs. The incidence of vomiting and the children's well-being were recorded at several time points over a 24-hour period. Parents were also asked to rate, on a scale of 0-6, how much their children were bothered by fasting, pain, and nausea/vomiting.

RESULTS

Age (4.8 +/- 2.6 years), weight (20 +/- 9 kg) and gender (73% boys) were comparable between the groups. The incidence of vomiting was 15% in the liberal and 22% in the fasting group (P = 0.39) and, between 1 and 12 h after extubation, children in the liberal group were significantly happier (P < 0.001). Children in the liberal group were significantly less bothered by their pain than those in the fasting group (P < 0.001).

CONCLUSION

Postoperative fasting did not reduce the incidence of vomiting after general anesthesia in children when compared with a liberal regimen. Furthermore, the ability to eat and drink at will decrease the bothersome aspects of pain and lead to happier patients.

Psychiatric emergencies in prehospital emergency medical systems: a prospective comparison of two urban settings

BACKGROUND

Psychiatric emergency situations (PES) are of high importance to the German prehospital physician-based emergency medical system. So far, however, no prospective studies regarding the incidence of PES have been performed, neither have effects of training programs on diagnostic and therapeutic accuracy been studied.

METHOD

The protocols of two emergency medical services (EMS) were collected and analyzed prospectively. Emergency physicians (EPs) in Kaiserslautern (KL) attended a standardized educational program and underwent daily supervision. EPs in Homburg (HOM) had not been informed about the study. In KL, sociodemographic variables were collected. An investigator who was not involved in the individual EMS mission assessed the correct classification of PES.

RESULTS

Among all calls for an EP, 11.8% were classified as PES. There was no difference between the two centers. Correct classification of PES in KL was significantly higher than that in HOM (94.3% vs. 80.6%). Documentation of suicidal behavior was deficient in both centers. EPs in KL gave verbal crisis intervention significantly more often, administered less medication overall, and dispensed more specific drugs in psychotic disorders and significantly less drugs in substance abuse disorders. Patients were more often treated at the scene and were less often transported to a hospital. Some sociodemographic variables were associated with psychiatric morbidity of treatment.

CONCLUSION

Accounting for 12% of all missions, psychiatric emergencies are a frequent reason for calls for EPs, equaling trauma-related and neurological emergencies. The most frequent reasons for calls were alcohol intoxication, states of agitation and suicidal behavior. The diagnostic and therapeutic accuracy of EPs may be improved with a concise standardized teaching program.

[Nausea and vomiting in the postoperative phase. Expert- and evidence-based recommendations for prophylaxis and therapy]

There are no consensus guidelines for the management of postoperative nausea and vomiting (PONV) in German speaking countries. This meeting was intended to develop such guidelines on which individual health care facilities can derive their specific standard operating procedures (SOPs). Anesthesiologists reviewed published literature on key topics which were subsequently discussed during two meetings. It was emphasized that recommendations were based on the best available evidence. The clinical relevance of individual risk factors should be viewed with caution since even well proven risk factors, such as the history of PONV, do not allow the identification of patients at risk for PONV with a satisfactory sensitivity or specificity. A more useful approach is the use of simplified risk scores which consider the presence of several risk factors simultaneously. Most individual antiemetic interventions for the prevention of PONV have comparable efficacy with a relative risk reduction of about 30%. This appears to be true for total intravenous anesthesia (TIVA) as well as for dexamethasone and other antiemetics; assuming a sufficiently high, adequate and equipotent dosage which should be weight-adjusted in children. As the relative risk reduction is context independent and similar between the interventions, the absolute risk reduction of prophylactic interventions is mainly dependent on the patient's individual baseline risk. Prophylaxis is thus rarely warranted in patients at low risk, generally needed in patients with a moderate risk and should include a multimodal approach in patients at high risk for PONV. Therapeutic interventions of PONV should be administered promptly using an antiemetic which has not been used before. The group suggests algorithms where prophylactic interventions are mainly dependent on the patient's risk for PONV. These algorithms should provide evidence-based guidelines allowing the development of SOPs/policies which take local circumstances into account.

The Efficacy of the Non-Opioid Analgesics Parecoxib, Paracetamol and Metamizol for Postoperative Pain Relief After Lumbar Microdiscectomy

In this prospective, double-blind, randomized, placebo-controlled study we compared the efficacy of three IV non-opioid analgesics for postoperative pain relief after lumbar microdiscectomy. Eighty healthy patients were randomly divided into 4 treatment groups (n = 20 each) to receive either parecoxib 40 mg, paracetamol 1 g, metamizol 1 g, or placebo IV 45 min before the end of surgery. In the postanesthesia care unit (PACU) patients were treated using patient-controlled analgesia (PCA) with piritramide. In the metamizol group the pain score at arrival in the PACU was significantly lower compared with the paracetamol, parecoxib, and placebo groups. In addition, in the metamizol group significantly fewer patients required additional PCA compared with the other groups studied. However, in those patients who required additional pain therapy in the four treatment groups, there was no significant difference in time to first request for piritramide and cumulative consumption of piritramide as assessed by the PCA data in the PACU. The incidence of adverse side effects was infrequent in all groups. These results suggest that in patients undergoing lumbar microdiscectomy, metamizol is superior to parecoxib, paracetamol, and placebo for immediate postoperative pain relief with minimal side effects.

Einfluss des Geschlechts auf Propofolverbrauch und Aufwachzeiten bei standardisierter Anästhesietiefe

INTRODUCTION

We investigated gender differences of drug consumption and recovery times for propofol-remifentanil anaesthesia.

METHODS

Adult patients scheduled for minor orthopaedic surgery were randomised to receive a propofol-remifentanil anaesthesia controlled either by EEG monitoring (Narcotrend or BIS) or solely by clinical parameters. Anaesthesia was induced with remifentanil 0.4 microg/kg/min and a propofol target-controlled infusion (TCI) at 3.5 microg/ml. After intubation remifentanil was reduced to 0.2 microg/kg/min whereas propofol TCI was adjusted according to clinical parameters or to the following EEG target values: during maintenance to "D(0)" (Narcotrend) or "50" (BIS), 15 min before the end of surgery to "C(1)" (Narcotrend) or "60" (BIS). Recovery times were recorded and average normalised propofol consumption was calculated from induction and maintenance doses.

RESULTS

A total of 60 male and 60 female patients completed the study. Gender differences were observed for recovery times (with standard practice) and for propofol consumption (with BIS monitoring). In the standard protocol group, propofol consumption was nearly identical for male and female patients whereas recovery times were significantly longer in the male group. In both EEG-guided groups propofol consumption was less for male patients while recovery times were slightly longer. In the group of female patients higher propofol TCI concentrations had to be used to reach the same BIS or Narcotrend values.

CONCLUSION

With propofol-remifentanil anaesthesia, gender has impact on recovery times and propofol consumption. If the same amounts of propofol are applied, males awake later, with BIS or Narcotrend monitoring males receive less propofol for comparable EEG effects.

Prospective application of a simplified risk score to prevent postoperative nausea and vomiting

PURPOSE

To compare the risk-adapted approach with ondansetron against ondansetron plus dexamethasone to prevent postoperative nausea and vomiting (PONV) in a randomized clinical trial.

METHODS

460 patients scheduled for elective surgery were enrolled in this prospective study and stratified according to a simplified risk score for PONV. Patients having no or one risk factor were considered at low risk (group L) and did not receive study medication. Those with two to four risk factors were considered high risk and were randomized to receive 4 mg ondansetron plus placebo (group H-O) or 4 mg ondansetron plus 8 mg dexamethasone (group H-OD). Incidence and intensity of PONV were observed for 24 hr after surgery. Data were analyzed with Fisher's exact or Student's t tests; P < 0.05 was considered statistically significant.

RESULTS

The incidence of PONV was 9% in group L (n = 87), 31% in those receiving ondansetron (group H-O, n = 185), and 22% in those receiving both drugs (group H-OD, n = 181). The incidence of PONV was significantly smaller in both high-risk groups than predicted without treatment (P < 0.001). While the incidence of PONV failed statistical significance between the two intervention groups (P = 0.08), the mean number of episodes of PONV and the mean maximal intensity of each episode of PONV were lower in group H-OD (P = 0.03 and P = 0.01, respectively). Patients of group H-OD required less antiemetic rescue therapy (P = 0.004).

CONCLUSIONS

Ondansetron plus dexamethasone prevents PONV more effectively than ondansetron alone in patients at high risk for PONV.

Eine faktorielle Studie von 6 Interventionen zur Vermeidung von �belkeit und Erbrechen nach Narkosen

BACKGROUND

Untreated, one third of patients who undergo surgery will have postoperative nausea and vomiting. Although many trials have been conducted, the relative benefits of prophylactic antiemetic interventions given alone or in combination remain unknown.

METHODS

In a randomized, controlled trial of factorial design, 5,199 patients at high risk for postoperative nausea and vomiting were randomly assigned to 1 of 64 possible combinations of 6 prophylactic interventions: 1) 4 mg of ondansetron or no ondansetron; 2) 4 mg of dexamethasone or no dexamethasone; 3) 1.25 mg of droperidol or no droperidol; 4) propofol or a volatile anesthetic; 5) nitrogen or nitrous oxide; 6) remifentanil or fentanyl. The primary aim parameter was nausea and vomiting within 24 h after surgery, which was evaluated blindly.

RESULTS

Ondansetron, dexamethasone, and droperidol each reduced the risk of postoperative nausea and vomiting by about 26%, propofol reduced the risk by 19%, and nitrogen by 12%. The risk reduction with both of these agents (i.e., total intravenous anesthesia) was thus similar to that observed with each of the antiemetics alone. All the interventions acted independently of each other and independently of the patients' baseline risk. Consequently, the relative risks associated with the combined interventions could be estimated by multiplying the relative risks associated with each intervention. However, absolute risk reduction was a critical function of patients' baseline risk.

CONCLUSIONS

Because antiemetic interventions are similarly effective and act independently, the safest or least expensive should be used first. Prophylaxis is rarely warranted in low-risk patients, moderate-risk patients may benefit from a single intervention, and multiple interventions should be reserved for high-risk patients.

A factorial trial of six interventions for the prevention of postoperative nausea and vomiting

BACKGROUND

Untreated, one third of patients who undergo surgery will have postoperative nausea and vomiting. Although many trials have been conducted, the relative benefits of prophylactic antiemetic interventions given alone or in combination remain unknown.

METHODS

We enrolled 5199 patients at high risk for postoperative nausea and vomiting in a randomized, controlled trial of factorial design that was powered to evaluate interactions among as many as three antiemetic interventions. Of these patients, 4123 were randomly assigned to 1 of 64 possible combinations of six prophylactic interventions: 4 mg of ondansetron or no ondansetron; 4 mg of dexamethasone or no dexamethasone; 1.25 mg of droperidol or no droperidol; propofol or a volatile anesthetic; nitrogen or nitrous oxide; and remifentanil or fentanyl. The remaining patients were randomly assigned with respect to the first four interventions. The primary outcome was nausea and vomiting within 24 hours after surgery, which was evaluated blindly.

RESULTS

Ondansetron, dexamethasone, and droperidol each reduced the risk of postoperative nausea and vomiting by about 26 percent. Propofol reduced the risk by 19 percent, and nitrogen by 12 percent; the risk reduction with both of these agents (i.e., total intravenous anesthesia) was thus similar to that observed with each of the antiemetics. All the interventions acted independently of one another and independently of the patients' baseline risk. Consequently, the relative risks associated with the combined interventions could be estimated by multiplying the relative risks associated with each intervention. Absolute risk reduction, though, was a critical function of patients' baseline risk.

CONCLUSIONS

Because antiemetic interventions are similarly effective and act independently, the safest or least expensive should be used first. Prophylaxis is rarely warranted in low-risk patients, moderate-risk patients may benefit from a single intervention, and multiple interventions should be reserved for high-risk patients.

A risk adapted approach reduces the overall institutional incidence of postoperative nausea and vomiting

PURPOSE

Routine prophylactic antiemetic treatment of surgical patients appears justified only in case of an increased risk of postoperative nausea and vomiting (PONV). The objective of this investigation was to assess the feasibility and efficacy of a dichotomized risk score adapted management of PONV based on ondansetron prophylaxis and treatment with respect to the overall institutional rate of PONV.

METHODS

After estimating the individual PONV risk by a simplified score, 162 adult patients scheduled for elective surgery received either 4 mg ondansetron intravenously (two to four risk factors = high-risk) or no prophylaxis (zero to one risk factor = low-risk). For antiemetic treatment ondansetron was given intravenously and orally. Incidence of PONV was recorded during the first 24 hr after recovery.

RESULTS

Data from 159 subjects were analyzed with 44 patients classified as low-risk and 115 patients classified as high-risk. Nine low-risk and 58 high-risk patients experienced PONV. The expected institutional PONV incidence of 47% was reduced to 36%. Treatment with ondansetron was necessary in seven low-risk and 37 high-risk patients with a complete response rate of 71% (low-risk) and 43% (high-risk).

CONCLUSION

Providing antiemetic prophylaxis with ondansetron to high-risk patients strictly based on a simplified risk score can reduce the overall institutional rate of PONV. However, classifying patients into two groups while using ondansetron as the single antiemetic in the high-risk group appears to be of limited efficacy as the incidence of PONV in high-risk patients is still double that of low-risk patients.

An international multicenter protocol to assess the single and combined benefits of antiemetic interventions in a controlled clinical trial of a 2×2×2×2×2×2 factorial design (IMPACT)

For various diseases clinicians have to combine different drugs or interventions when a single drug or intervention does not lead to satisfactory results. However, quantifying the relative benefit of certain drugs or interventions when given alone and in combination under controlled conditions requires a complex factorial design. This paper describes such a method applied to a large multicenter trial for the prevention of postoperative nausea and vomiting (PONV), which may be of great interest for other specialties. Approximately 28 million operations are performed annually in the United States, mainly under general anesthesia with volatile anesthetics. Unfortunately, one-third of these patients suffer from PONV. This prompted extensive research of antiemetic and anesthetic drugs, but none of the interventions appeared to satisfactorily prevent PONV. Scuderi et al. were the first to almost eliminate PONV by combining various antiemetic interventions; however, the relative benefit of each intervention remained unclear. Accordingly, we have designed a large randomized controlled trial studying six different antiemetic interventions-three involving use of various antiemetic drugs and three involving choice of anesthetic drugs-to answer the following main questions: (1) What is the relative benefit of each of the antiemetic intervention? (2) Are certain combinations of antiemetic interventions more effective than others? Using a complete factorial design this leads to 2(3)=8 antiemetic combinations, which multiply with the 2(3)=8 combinations of anesthetic drugs, leading to a total of 2(6)=64 possible combinations. The six factors are the antiemetics ondansetron (versus control), dexamethasone (versus control), droperidol (versus control), and the intravenous anesthetic propofol (versus volatile anesthetics), air (versus nitrous oxide), and remifentanil (versus fentanyl). The primary outcome is freedom from PONV within the first 24 hours after anesthesia. Eligible patients are adults scheduled for elective surgery under general anesthesia with an increased risk for PONV so that the expected incidence in the control group (with none of the six antiemetic interventions) is approximately 60%. In order to allow analyses for up to three factor interactions, a sample size was estimated to be in the range of approximately 5000 patients. To the best of our knowledge this is the first randomized controlled trial of a six-way factorial design that may serve as an example for numerous other medical specialties.

H�modynamische Reaktionen nach pr�operativer hypervol�mischer H�modilution mit hyperton-hyperonkotischen Kolloiden bei Koronarbypassoperationen

OBJECTIVE

Using hyperoncotic colloids as volume replacement to provide haemodynamic stability appears to be a suitable approach to diminish fluid overload and subsequent interstitial edema during cardiac surgery. The aim of the present study was to investigate for the first time the haemodynamic effects following preoperative haemodilution with different hypertonic hyperoncotic colloid solutions in patients undergoing coronary artery bypass grafting.

METHODS

A total of 43 patients with normal left ventricular ejection fraction, undergoing elective coronary artery bypass grafting received preoperatively after induction of anaesthesia according to randomisation the following solutions: 1: 750 ml/m(2) (body surface area) NaCl 0.9% ( n=10, control group, NACL), 2: 250 ml/m(2) 10% HES 200/0.5 plus 400 ml/m(2) NaCl 0.9% ( n=9, HES), 3: 250 ml/m(2) 10% dextran 40 plus 300 ml/m(2) NaCl 0.9% ( n=8, DEX), 4: 150 ml/m(2) hypertonic NaCl (7.2%) 10% HES 200/0.5 (n=8, HYPER-HES), 5: 150 ml/m(2) hypertonic NaCl (7.2%) 10% dextran 60 ( n=8, HYPER-DEX). Haemodynamic measurements were performed immediately before and 15 min after haemodilution and up to 60 min after termination of extracorporeal circulation in 10 min intervals. Fluid balances were calculated separately, during the time period of surgery, postoperatively up to 24 h after termination of surgery, and during the course of extracorporeal circulation.

RESULTS

After haemodilution with colloid solutions, a marked increase was observed in all patients and with HYPER-HES and HYPER-DEX a statistically significant increase in cardiac index (CI: +38%, +54%), stroke volume index (SVI: +42%, +40%), and oxygen availability (DO2: +34%; +41%), respectively, was observed during the pre-bypass period. At the same time right and left ventricular filling pressures increased slightly in all patients but these changes did not differ among the treatment groups. Heart rate and mean arterial pressure remained almost unchanged in all groups. The amount of crystalloid solutions required by the patients during surgery was markedly decreased with HES and DEX and significantly decreased with HYPER-HES and HYPER-DEX (1,013+/-341 ml/m(2), 1,096+/-234 ml/m(2)) compared to the control group NACL (1629+/-426 ml/m(2)). Serum sodium concentrations increased with HYPER-HES and HYPER-DEX to maximal values of 150+/-3 mmol/l and 149+/-4 mmol/l, respectively (baseline 141+/-3 mmol/l, 141+/-1 mmol/l)

CONCLUSIONS

Compared to isotonic saline solution, preoperative volume replacement with hyperoncotic colloids improves haemodynamic conditions during the pre-bypass period in patients with normal left ventricular function undergoing coronary artery bypass grafting. Additionally intraoperative crystalloid solution requirements are reduced. The volume saving effects are increased with administration of hyperoncotic colloids in a preparation with hypertonic saline solution, whereas the choice of the colloid, either hydroxyethyl starch or dextran seems to be of minor importance.

Narcotrend monitoring allows faster emergence and a reduction of drug consumption in propofol-remifentanil anesthesia

BACKGROUND

The Narcotrend is a new electroencephalographic monitor designed to measure depth of anesthesia, based on a six-letter classification from A (awake) to F (increasing burst suppression) including 14 substages. This study was designed to investigate the impact of Narcotrend monitoring on recovery times and propofol consumption in comparison to Bispectral Index (BIS) monitoring or standard anesthetic practice.

METHODS

With institutional review board approval and written informed consent, 120 adult patients scheduled to undergo minor orthopedic surgery were randomized to receive a propofol-remifentanil anesthetic controlled by Narcotrend, by BIS(R), or solely by clinical parameters. Anesthesia was induced with 0.4 micro x kg-1 x min-1 remifentanil and a propofol target-controlled infusion at 3.5 microg/ml. After intubation, remifentanil was reduced to 0.2 micro x kg-1 x min-1, whereas the propofol infusion was adjusted according to clinical parameters or to the following target values: during maintenance to D(0) (Narcotrend) or 50 (BIS); 15 min before the end of surgery to C(1) (Narcotrend) or 60 (BIS). Recovery times were recorded by a blinded investigator, and average normalized propofol consumption was calculated from induction and maintenance doses.

RESULTS

The groups were comparable for demographic data, duration of anesthesia, and mean remifentanil dosages. Compared with standard practice, patients with Narcotrend or BIS monitoring needed significantly less propofol (standard practice, 6.8 +/- 1.2 mg x kg-1 x h-1 vs. Narcotrend, 4.5 +/- 1.1 mg x kg-1 x h-1 or BIS(R), 4.8 +/- 1.0 mg x kg-1 x h-1; P < 0.001), opened their eyes earlier (9.3 +/- 5.2 vs. 3.4 +/- 2.2 or 3.5 +/- 2.9 min), and were extubated sooner (9.7 +/- 5.3 vs. 3.7 +/- 2.2 or 4.1 +/- 2.9 min).

CONCLUSIONS

The results indicate that Narcotrend and BIS monitoring are equally effective to facilitate a significant reduction of recovery times and propofol consumption when used for guidance of propofol titration during a propofol-remifentanil anesthetic.

Postoperative myalgia after succinylcholine: no evidence for an inflammatory origin

A common side effect associated with succinylcholine is postoperative myalgia. The pathogenesis of this myalgia is still unclear; inflammation has been suggested but without convincing evidence. We designed the present study to investigate whether an inflammatory reaction contributes to this myalgia. The incidence and severity of succinylcholine-associated myalgia was determined in 64 patients pretreated with saline or dexamethasone before succinylcholine (n = 32 for each). Incidence and severity of myalgia did not differ significantly between the two groups: 15 patients in the dexamethasone group complained of myalgia compared with 18 patients in the saline group, and severe myalgia was reported by five patients and three patients, respectively (not significant). At 48 h after surgery, 12 patients in both groups still suffered from myalgia (not significant). In addition, interleukin-6 (IL-6) as an early marker of inflammation was assessed in a subgroup of 10 patients pretreated with saline. We found an increase of IL-6 for only three patients, but only one patient reported myalgia; no relationship between myalgia and the increase of IL-6 was found. In conclusion, there is no evidence for an inflammatory origin of succinylcholine-associated myalgia.

IMPLICATIONS

Administration of dexamethasone before succinylcholine was not effective in decreasing the incidence or the severity of succinylcholine-induced postoperative myalgia. Furthermore, there was no significant relationship between postoperative myalgia and time course of interleukin-6 concentrations, a marker of inflammation. Pretreatment with dexamethasone is not justified to prevent postoperative myalgia after succinylcholine.

[Procalcitonin plasma concentrations and systemic inflammatory response following different types of surgery]

OBJECTIVE

Procalcitonin (PCT) is currently recommended as a suitable parameter to detect and to evaluate the course of bacterial, fungal or parasitic infections. However, recent studies provide evidence that surgical trauma and humoral mediators of inflammation, respectively,may induce PCT synthesis, thereby reducing the validity and reliability of PCT as an "infection-monitoring" parameter. The aim of the present study was to assess and to compare PCT and CRP (C-reactive protein) plasma concentrations in patients presenting without infection following different types of surgery in the absence or presence of a systemic inflammatory response syndrome (SIRS).

METHODS

PCT and CRP plasma concentrations were assessed daily on postoperative days 1-5 and maximal values were determined in 94 patients. The patients were allocated to four groups of different types of surgery as follows: A: minor, primarily aseptic surgery, B: major abdominal surgery, C: major vascular surgery and D: thoracic surgery including esophagectomy. All categories were divided into two subgroups representing patients with and without SIRS, respectively. RESULTS. PCT plasma concentrations increased moderately compared to normal values in 21% of patients after minor and aseptic surgery (A), in 27% and 41% after major vascular (C) and thoracic (D) surgery, respectively, and in 65% of patients after major abdominal (B) surgery. The difference between PCT concentrations in patients undergoing major abdominal surgery and the patients after minor, aseptic surgery was significant ( p<0,05: A vs. B). Comparing the patients presenting with or without systemic inflammatory response (SIRS), no significant differences in PCT concentrations between groups could be observed. In the majority of patients PCT values rose to peak levels on the first and second postoperative days, followed by a rapid decline based on the plasma half-life of PCT. In contrast, postoperative CRP plasma concentrations were markedly elevated above normal values in all investigated patients during the whole observation period. Between-categories statistical analysis revealed significant differences comparing patients undergoing minor and aseptic surgery with patients after major vascular, and thoracic surgery, respectively ( p<0,05,A vs.C, D). CRP concentrations were significantly increased in patients with systemic inflammatory response compared to patients with normal postoperative course in surgical categories B, C, and D, respectively ( p<0,05).

CONCLUSIONS

Postoperative PCT plasma concentrations in patients presenting without signs of infection are largely influenced by the type of surgical procedure. During the first and second postoperative day PCT concentrations are more frequently elevated in patients after major abdominal, major vascular and thoracic surgery compared to patients undergoing minor, aseptic operations. Thus an "infection monitoring" considering PCT value analysis during the postoperative course may transiently be impeded after major and particularly after intestinal surgery during the first 2 days postoperatively, whereas it appears not to be substantially affected by the presence or absence of systemic inflammatory response.

[Narcotrend stages and end-tidal desflurane concentrations. An investigation during recovery from desflurane/remifentanil anaesthesia]

OBJECTIVE

[corrected] As indicated by the manufacturer the EEG monitor Narcotrend trade mark (MonitorTechnik, Bad Bramstedt) can be used to analyse EEG effects of volatile anaesthetics, however, published data are missing. This study evaluated the emergence from a desflurane/remifentanil anaesthetic and was designed to investigate the relationship between Narcotrend stages (version 2.0 AF) and end-tidal desflurane concentrations and to identify the pattern of changes of the Narcotrend stages during recovery.

METHODS

Adult patients scheduled for orthopaedic surgery were premedicated with 0.15 mg/kg diazepam orally in the evening and on the morning before surgery. Narcotrend EEG electrodes were positioned on the patient's forehead as recommended by the manufacturer. For induction of anaesthesia, remifentanil was infused at 0.4 microgram/kg/min and propofol 2 mg/kg was given for hypnosis. After neuromuscular blockade and orotracheal intubation, remifentanil was reduced to 0.2 microgram/kg/min, and desflurane in O(2)/air was added according to clinical needs. After termination of surgery, administration of anaesthetics was discontinued and simultaneously, the fresh gas flow was increased to 10 l/min of O(2) while the respirator pattern was left unchanged. Narcotrend stages and end-tidal desflurane concentrations were recorded as data pairs at intervals of 1 min during emergence from anaesthesia; data evaluation included the last 7 min before extubation.

RESULTS

A total of 50 patients (mean age +/-SD 44.4+/-13.0 years) were studied and 400 data pairs were obtained. A decreasing depth of anaesthesia as indicated by the Narcotrend was associated with significantly lower end-tidal desflurane concentrations: for E (general anaesthesia with deep hypnosis) 3.6+/-1.0 vol%, for D (general anaesthesia) 1.7+/-0.8 vol%, for C (light anaesthesia) 0.7+/-0.3 vol% and for A and B (awake or sedated) 0.5 vol%. A reduction of end-tidal desflurane concentrations was accompanied by a shift of Narcotrend stages from C/D/E to A/B/C.

CONCLUSION

During emergence from desflurane/remifentanil anaesthesia, a reduction of end-tidal desflurane concentrations was detected by the EEG monitor Narcotrend and classified as a typical change of distribution of Narcotrend stages.

Comparison of the effects of remifentanil or fentanyl on anaesthetic induction characteristics of propofol, thiopental or etomidate

BACKGROUND AND OBJECTIVE

This prospective, randomized, double-blinded study was designed to compare the effects of remifentanil or fentanyl on anaesthetic induction characteristics of propofol, thiopental or etomidate.

METHODS

Seventy-two patients were enrolled in six groups of 12 individuals each. In three groups, fentanyl was given as a bolus dose of 1.5 microg kg(-1), whereas the others received a remifentanil infusion at 0.5 microg kg(-1) min(-1). Five minutes later, propofol, thiopental or etomidate were titrated to a state of unresponsiveness. Assessment included the amounts of drug necessary for induction, haemodynamics and the times to apnoea, loss of eyelash reflex, and the release of a water-filled syringe held in the patient's hand.

RESULTS

Induction times to loss of the eyelash reflex were significantly shorter in the remifentanil than in the fentanyl groups: with propofol 50.7 +/- 13.6s (mean +/- SD) versus 74.9 +/- 27.0s (P < 0.01), with thiopental 42.9 +/- 16.8s versus 77.2 +/- 27.8s (P < 0.01) and with etomidate 54.7 +/- 17.6s versus 72.3 +/- 24.0s (P < 0.05). The times to respiratory arrest or for the syringe to fall were significantly shorter with remifentanil than with fentanyl for propofol and for thiopental, but not for etomidate. In terms of dosages per kg body weight necessary to achieve unresponsiveness, less propofol (-29%, P < 0.05), thiopental (-25%, P < 0.05) or etomidate (-32%, P < 0.01) was necessary with remifentanil than with fentanyl. Haemodynamic responses to tracheal intubation were controlled more effectively with remifentanil. However, within the remifentanil groups, mean arterial pressure significantly decreased during induction: -26% with propofol, -181% with thiopental and -14% with etomidate (all P < 0.01).

CONCLUSIONS

During anaesthetic induction, a remifentanil infusion of 0.5 microg kg(-1) min(-1) over 5 min is a suitable alternative to a 1.5 microg kg(-1) bolus dose of fentanyl: induction times are shorter with reduced amounts of propofol, thiopental or etomidate.

General anesthesia versus monitored anesthesia care with remifentanil for assisted reproductive technologies: effect on pregnancy rate

STUDY OBJECTIVES

To compare the outcome of assisted reproductive technology procedures in women who undergo monitored anesthesia care (MAC) with remifentanil versus general anesthesia.

DESIGN

Retrospective data analysis.

SETTING

University hospital.

PATIENTS

251 ASA physical status I and II women participating in an in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) program.

INTERVENTIONS

During the first phase of the study, all patients underwent general anesthesia induction with alfentanil, propofol, and nitrous oxide, which was maintained with isoflurane or propofol infusion. In the second phase of the study, all patients received a standardized MAC technique with a remifentanil infusion; local anesthetics were not used.

MEASUREMENTS

The primary endpoint was pregnancy rate per transfer. The number of oocytes collected, fertilized, and cleaved was recorded, as was the number of oocytes transferred.

MAIN RESULTS

Patients who underwent MAC had a greater pregnancy rate with IVF (28.2 vs. 16.3%), with ICSI (32.2% vs. 18.8%), and overall (30.6% vs. 17.9%).

CONCLUSIONS

Pregnancy rates in women undergoing transvaginal oocyte retrieval for assisted reproductive technologies were significantly higher with a remifentanil-based MAC technique than with a general anesthetic technique.

The Narcotrend--a new EEG monitor designed to measure the depth of anaesthesia. A comparison with bispectral index monitoring during propofol-remifentanil-anaesthesia

INTRODUCTION

The Narcotrend is a new EEG monitor designed to measure the depth of anaesthesia based on a 6-letter classification from A (awake) to F (general anaesthesia with increasing burst suppression) and divided into 14 substages (A, B0-2, C0-2, D0-2, E0,1, F0,1). This study was designed to investigate the assessment of the depth of anaesthesia as measured by the Narcotrend in comparison with bispectral index monitoring (BIS).

METHODS

Both BIS and Narcotrend EEG electrodes were positioned on the patient's forehead as recommended by the manufacturers. All patients were premedicated with diazepam 0.15 mg/kg orally in the evening and on the morning before surgery. Induction of anaesthesia was started with a remifentanil infusion at 0.4 microgram/kg/min; 5 min later propofol was given for hypnosis using a target-controlled infusion initially started at 3.5 micrograms/ml. After loss of consciousness patients received 1.2 mg/kg of suxamethonium. Immediately after intubation, remifentanil was reduced to 0.2 microgram/kg/min, and the depth of anaesthesia was adjusted according to clinical needs by regulating the propofol target-controlled-infusion. BIS values and Narcotrend stages were recorded as data pairs in intervals of 1 min during anaesthetic induction and emergence, and in intervals of 5 min during maintenance of anaesthesia.

RESULTS

Fifty patients undergoing orthopaedic surgery were studied and 2031 data pairs were obtained. An increasing depth of anaesthesia as indicated by the Narcotrend was associated with significantly lower mean BIS values. With BIS values between 100 and 85 (representing awake patients), 95.5% of all data pairs indicated a Narcotrend stage A or B. In case the BIS was found to be 65-40 (representing general anaesthesia) the corresponding Narcotrend stages were measured as D (52.4%) or E (41.1%). No patient complained of intraoperative recall when interviewed on the 1st and 3rd postoperative day.

CONCLUSIONS

We could demonstrate that an increase of the hypnotic component of anaesthesia as indicated by BIS is accompanied by corresponding effects as displayed by the Narcotrend during propofol-remifentanil anaesthesia. The Narcotrend stages D or E are assumed equivalent to BIS values between 64 and 40 indicating general anaesthesia.

[Less pain on injection by a new formulation of propofol? A comparison with propofol LCT]

BACKGROUND

Pain on injection is a major disadvantage of propofol, experienced by the vast majority of patients. Since the traditional formulation has almost normal osmolality and pH, it is hypothesised that the concentration of free propofol in the aqueous phase of the emulsion is responsible for the pain and that reducing the amount of free propofol would also reduce the frequency and intensity of pain on injection. This study was designed to investigate whether pain on injection can be reduced in frequency and intensity by a new formulation of propofol.

METHODS

We performed a monocentre, controlled, randomised, double-blind study to compare the pain produced by intravenous injection of a new propofol preparation (propofol-MCT/LCT) with standard propofol in patients undergoing elective surgical procedures. A total of 184 non-premedicated patients received either 1% propofol prepared in a mixture of medium and long chain triglycerides (Propofol-MCT/LCT, Propofol- Lipuro, B. Braum Melsungen AG) or standard 1% propofol prepared exclusively in long chain triglycerides (Propofol-LCT; Disoprivan, AstraZeneca) into a vein of the dorsal hand for induction of anaesthesia. Anaesthesia was maintained by TIVA with propofol and remifentanil. Pain on injection was recorded and graded as none, mild, moderate or severe.

RESULTS

Patients receiving propofol-MCT/LCT had a significantly lower incidence of pain on injection compared to the standard propofol group (37% vs 64%) with the intensity of pain also being less severe. There were no differences between both groups in propofol dosage for induction (3.2 +/- 0.8 mg/kg vs 3.3 +/- 0.9 mg/kg) and maintenance of anaesthesia (3.4 +/- 0.6 mg/kg/h vs 3.2 +/- 0.5 mg/kg/h), remifentanil dosage (25 +/- 6 micrograms/kg/h vs. 24 +/- 6 micrograms/kg/h), intraoperative hemodynamics, recovery parameters and postoperative patient satisfaction. Postoperative thrombophlebitis at the injection site for propofol was not observed in any of the patients.

CONCLUSIONS

Propofol-MCT/LCT produced significantly less pain on injection when compared to standard propofol in ASA I and II patients undergoing elective surgery. Pain was also significantly less severe, with both effects presumably being due to the lower concentration of free propofol in the MCT/LCT-preparation. With regard to injection pain propofol-MCT/LCT offers significant a advantage over standard propofol.

Recovery after remifentanil and sufentanil for analgesia and sedation of mechanically ventilated patients after trauma or major surgery

We investigated the analgesic effect and the neurological recovery time after administration of remifentanil in mechanically ventilated patients in an intensive care unit. Twenty patients, after trauma or major surgery with no intracranial pathology, were randomized to receive either remifentanil/propofol (n=10) or sufentanil/propofol (n=10). A sedation score and a simplified pain score were used to assess adequate sedation and analgesia. Medication was temporarily stopped after 24 h. Immediately before and 10 and 30 min after, the degree of sedation and pain score were evaluated. Adequate analgesia and sedation was achieved with remifentanil 10.6 microg kg(-1) h(-1) and propofol 2.1 mg kg(-1) h(-1), or sufentanil 0.5 microg kg(-1) h(-1) and propofol 1.3 mg kg(-1) h(-1). The difference in propofol dose between groups was significant. Ten minutes after terminating the medication, the degree of sedation decreased significantly after remifentanil and all patients could follow simple commands. During the following 20 min, all patients with remifentanil emerged from sedation and complained of considerable pain. By contrast, in the sufentanil group, only six (7) responded to commands after 10 (30) min and their pain score remained essentially unchanged during the 30-min observation period. We conclude that, in contrast to sufentanil, remifentanil facilitates rapid emergence from analgesia and sedation, allowing a clinical neurological examination within 10-30 min in mechanically ventilated patients with no intracranial pathology.

[Gamma-hydroxybutyric acid-ethanolamide (LK 544). The suitability of LK 544 for sedation of patients in intensive care in comparison with midazolam]

OBJECTIVE

In this phase 2 study gammahydroxybutyric acid-ethanolamide (GHB-ethanolamide) was compared with midazolam for sedation of patients in the intensive care unit (ICU). GHB-ethanolamide is a new derivative of gammahydroxybutyric acid, a drug commonly used for sedation in intensive care patients.

METHODS

A total of 29 non-intubated, spontaneously breathing patients following major surgery, were randomly assigned to 2 groups: group A (n = 14) received 150 mg/kg GHB-ethanolamide i.v. followed by 150 mg/kg/h. Group B (n = 15) received 0.025 mg/kg midazolam i.v. followed by 0.025 mg/kg/h. The degree of sedation was assessed over a 3-5 h period both clinically by the Ramsay Score and by the spectral frequency index (SFx), derived by continuous computerized EEG recording (CATEEM).

RESULTS

EEG: the SFx showed a significantly deeper sedation compared to baseline values, 10, 60 and 120 min after start of sedation in the GHB-ethanolamide group. By contrast, no difference could be observed compared to baseline values in the midazolam group. A comparison between both groups showed a deeper sedation in the GHB group 60 and 120 min after start of sedation. The Ramsay Score increased from baseline values of 2.0 (2.0/2.0) to 3.0 (2.0/3.0) during sedation (Median (25th/75th percentile) and no significant differences could be observed between groups. In the Midazolam group the sedation of two patients had to be terminated because of side effects (Ramsay Score 6 and paradoxical, agitated reaction).

CONCLUSIONS

GHB-ethanolamide produces adequate sedation for extubated and spontaneously breathing ICU patients. The drug might be safer than midazolam with regards to side effects such as respiratory depression.

[Ocular injuries and triage after the bombing attack on the United States embassy in Nairobi (Kenya)]

BACKGROUND

As a result of the terrorist bombings of the United States Embassies in Daressalam (Tansania) and Nairobi (Kenya) on August 7, 1998, over 200 people were killed. 5000 persons were injured severely. The purpose of this article is to provide a review of our experiences in the evaluation and treatment of patients with multiple simultaneous ocular injuries sustained in the Nairobi attack.

PATIENTS AND METHODS

We treated eight survivors of the assault, four of them with extremely severe eye injuries. A three-tiered system of triage developed. The first level occurred on scene, in which minor injuries were treated locally and more severe injuries were transported by aeromedical evacuation to Landstuhl Regional Medical Center (LMRC), in Germany among other locations. Surgical exploration of all patients arriving at LRMC was performed and surgical repair was undertaken when appropriate and technically possible. Patients requiring vitreoretinal surgery were transferred either to Saarland University Eye Hospital, Homburg, Germany, or Walter Reed Army Medical Center, Washington, DC.

RESULTS

Only one eye required enucleation, due to an almost complete extrusion of the retina. It was possible to stabilize even severely injured eyes with multiple intraocular foreign bodies.

CONCLUSIONS

Modern microsurgical techniques such as temporary keratoprothesis, perforating keratoplasty, and pars plana vitrectomy can now save eyes and often allow restoration of usuable visual acuity where this once have been deemed impossible.

Interpleural analgesia does not influence postthoracotomy pain

The management of postthoracotomy pain is a problem and may contribute to atelectasis, leading to hypoxemia, pulmonary infection, and permanent alveolar damage. We sought to determine the efficacy of interpleural analgesia for pain control and to evaluate independent predictors for postoperative pain intensity. Eighty-three patients undergoing elective anterolateral (n = 37) and posterolateral (n = 46) thoracotomy were included in a prospective, randomized, double-blinded trial. Patients were assigned to receive either 0.5% bupivacaine or saline solution interpleurally every 4 h for 10 doses postoperatively. All patients also received patient-controlled analgesics (PCA) with piritramide as the opioid for additional pain control. Pain was assessed on the basis of PCA requirements and by using a visual analog scale. Visual analog scale scores and PCA requirements were not different between groups. Both interpleural bupivacaine and saline significantly reduced pain scores 30 min after the administration. We concluded that pain reduction by interpleural instillation of bupivacaine reflects a placebo-like effect; however, interpleural analgesia is not effective in patients undergoing lateral thoracotomy. Sex and surgical approach were shown to influence postoperative pain intensity at rest, but not during coughing. The female patients, and those undergoing posterolateral thoracotomy, exhibited higher pain scores. This observation appears to be of only marginal clinical significance. The efficacy of interpleural analgesia to reduce postoperative pain intensity in patients after lateral thoracotomy is controversial. In this study we demonstrated a lack of efficacy of interpleural analgesia.

IMPLICATIONS

The efficacy of interpleural analgesia to reduce postoperative pain intensity in patients after lateral thoracotomy is controversial. In this study, we demonstrated a lack of efficacy of interpleural analgesia.

[Cognitive impairment in the early postoperative period after remifentanil-propofol and sevoflurane-fentanyl anesthesia]

OBJECTIVE

In ambulatory anaesthesia the time required to recover from cognitive impairment should be as short as possible. The aim of this study was to compare the early cognitive recovery after remifentanil/propofol (R/P) and sevoflurane/fentanyl (S/F) anaesthesia.

METHODS

Sixty patients scheduled for elective gynaecological laparoscopy and 24 female volunteers tested for the assessment of learning effects were investigated. After praemedication with midazolam anaesthesia was induced with propofol, atracurium and either 1 microgram/kg fentanyl or 1 microgram/kg remifentanil. For maintenance 0.25 microgram/kg/min remifentanil and 0.6 mg/kg/min propofol (R/P) or 1.7 vol% sevoflurane (S/F) were given. Both groups were ventilated with 30% oxygen in air and received metamizol for postoperative analgesia. Verbal Learning Test, Stroop Colour and Word Interference Test, Digit Symbol Substitution Test and Four Boxes Test were performed the day before surgery and 30 min, 1 h, 2 h and 4 h after termination of anaesthesia.

RESULTS

For remifentanil/propofol cognitive function was still impaired 2 h (Verbal Learning) and 4 h (Stroop, Digit Symbol Substitution and Four Boxes Test) after termination of anaesthesia. After sevoflurane/fentanyl anaesthesia cognitive impairment lasted the same duration in Four Boxes Test, but shorter in Stroop and Digit Symbol Substitution and could not be found in Verbal Learning Test.

CONCLUSION

The duration of cognitive impairment in the early postoperative period differed by the test procedures and the anaesthetic procedures used in this investigation. Recovery appeared to be faster after sevoflurane/fentanyl than after remifentanil/propofol at least in aspects of cognitive function.

[Preanalytical errors on the determination of arterial O(2)-partial pressure and their impact on the AaDO(2)]

OBJECTIVES

The paO(2) and AaDO(2) are routinely measured for evaluating pulmonary gas exchange. The normal value of the AaDO(2) amounts 10 mmHg when breathing atmospheric air and is said to increase with rising FIO(2). This increase is discussed controversially. One possible reason for incongruities in AaDO(2) measurement may be the impact of so called preanalytical errors during paO(2) measurement, which are often neglected. Therefore, the aim of this study was to evaluate the relevance of preanalytical errors on the AaDO(2) under hyperoxic conditions.

METHODS

Arterial blood gas analysis was performed on twenty patients without known pulmonary disease after tracheal intubation and 30 min of ventilation with pure oxygen. All preanalytical paO(2) errors (sampling technique, transport and storage of samples, aspirated air bubbles) were assessed and all paO(2) measurements were corrected by applying respective predetermined correction factors. Calculation of the AaDO(2) was performed with corrected and uncorrected paO(2) values.

RESULTS

The average amount of the AaDO(2) under ventilation with FIO(2)=1.0 was 118.9+/-41.1 mmHg, calculated from uncorrected paO(2) values, and 13.4+/-7.5 mmHg calculated from paO(2) values corrected for preanalytical errors, respectively.

CONCLUSION

The present results show that the assumption of an increasing AaDO(2) with rising FIO(2) is questionable. It could be proved that neglecting preanalytical paO(2) errors leads to a significant overestimation of the AaDO(2). The consequence would be a misinterpretation of the patient's condition in relation to a reduced pulmonary gas exchange, which should in fact be attributed solely to the preanalytical errors.

[Postoperative cognition disorders in elderly patients. The results of the "International Study of Postoperative Cognitive Dysfunction" ISPOCD 1)]

OBJECTIVE

Cognitive dysfunction is a known problem after operations and may be especially relevant in the elderly. The aim of this international multicentre study was to investigate short- and long-term cognitive dysfunction in elderly patients and to elucidate the relevance of hypoxaemia and hypotension as causative factors.

METHODS

1218 patients aged 60 years and older and scheduled for major non-cardiac surgery under general anaesthesia were investigated. Oxygen saturation was measured by continuous pulse oximetry before surgery and throughout the day of and the first 3 nights after surgery. Blood pressure was recorded every 3 minutes during the operation and every 15-30 min for the rest of that day and night. Cognitive testing was performed before and 1 week and 3 months after the operation. Cognitive dysfunction was identified with neuropsychological tests compared with controls recruited from the UK (n = 176) and the same countries as study centres (n = 145).

RESULTS

Postoperative cognitive dysfunction was present in 25.8% of patients 1 week after surgery and in 9.9% 3 months after surgery, compared with 3.4% and 2.8%, respectively, of the UK controls. Increasing age and duration of anaesthesia, little education, a second operation, postoperative infections, and respiratory complications were the risk factors for early postoperative cognitive dysfunction, but only age was a risk factor for long-term postoperative cognitive dysfunction. Hypoxaemia and hypotension were not significant risk factors at any time.

CONCLUSION

With this investigation long-term cognitive dysfunction could be proven definitively for elderly patients after major operations under general anaesthesia. No factors with prophylactic or therapeutic influence were detectable so that aetiology and pathophysiology of POCD could not be further determined.

[TIVA with propofol-remifentanil or balanced anesthesia with sevoflurane-fentanyl in laparoscopic operations. Hemodynamics, awakening and adverse effects]

OBJECTIVE

This study was designed to investigate the differences between TIVA with propofol/remifentanil (P/R) and balanced anaesthesia with sevoflurane/fentanyl (S/F) in gynaecological laparoscopic surgery. Emphasis was put on haemodynamic reaction, recovery profile, postoperative side effects and patient satisfaction.

METHODS

Sixty patients were randomly assigned to receive either total intravenous anaesthesia with propofol/remifentanil or anaesthesia with sevoflurane/fentanyl. After premedication (midazolam) and induction of anesthesia (propofol, atracurium) in both groups, either 1 microgram/kg fentanyl (S/F) or 1 microgram/kg remifentanil (P/R) was injected. Anaesthesia was maintained with 0.5 microgram/kg/min remifentanil (reduced to 50% after 5 min) and 0.06 microgram/kg/min propofol (P/R) or 1.7 vol % sevoflurane (S/F). Both groups were mechanically ventilated with 30% oxygen in air. The administration of sevoflurane and the infusion of the anaesthetics were adjusted to maintain a surgical depth of anaesthesia. For postoperative analgesia 1 g paracetamol was administered rectally prior to surgery. After recovery 20 mg/kg metamizol was given intravenously. At the end of surgery the anaesthetics were discontinued and haemodynamics, early emergence from anaesthesia, pain level, frequency of analgesic demand, incidence of PONV, shivering and patient satisfaction were assessed. Parameters were recorded for 24 h postoperatively.

RESULTS

Recovery time after propofol-remifentanil anaesthesia was significantly shorter than after administration of sevoflurane and fentanyl (spontaneous ventilation 4.1 vs. 6.3 min, extubation 4.3 vs. 9.3 min, eye opening 4.4 vs 8.2 min, stating name 5.3 vs. 13.2 min, stating date of birth 5.4 vs. 13.3 min). There were no significant differences between the groups in shivering, pain score, analgesic demand and PONV. The S/F group responded to tracheal intubation with significantly higher blood pressure than the P/R group. During maintenance of anaesthesia heart rate in patients with S/F was significantly higher (P/R:HR max +16/-10; S/F:HR max +24/-0.). Measured on a scale (S/F 62%).

CONCLUSION

Compared with patients given balanced anaesthesia with sevoflurane and fentanyl, TIVA with propofol and remifentanil proved to be particularly suited for gynaecological laparoscopic surgery. Its major advantages are haemodynamic stability, significantly shorter times of emergence, and the exceptional acceptance by the patients.

[Puerperal sepsis due to infected episiotomy wound]

A healthy 31-year-old woman showed a severe septic shock syndrome a few days after vaginal delivery. In the episiotomy wound were found Group A Streptococci and E. coli. Although an antibiotic therapy was instituted immediately, the condition of the patient worsened. Platelet counts fell below 5000/microliter and she developed respiratory, cardiocirculatory and renal insufficiency, so that mechanical ventilation, high-dose-catecholamine therapy and continuous venovenous hemodiafiltration had to be performed. In the course of the disease the patient showed a reversible cardiomegaly with pulmonary hypertension and an extensive desquamation of the skin. Fever persisted in spite of the fact that in all following clinical and laboratory examinations no septic focus could be revealed any longer. She recovered slowly and could not be weaned from the respirator for four weeks because of a severe critical illness polyneuromyopathy.

[Remifentanil for oocyte retrieval: A new single-agent monitored anaesthesia care technique]

INTRODUCTION

Transvaginal puncture for oocyte retrieval is a short-lasting but painful procedure. We hypothesized that a sole infusion of the ultra-short acting mu-agonist remifentanil may be a suitable and well-controllable single-agent analgesic technique that can dose-dependently be applied to spontaneously breathing patients.

METHODS

Fifty consenting adult women were enrolled in this prospective trial. A sedative premedication was omitted, all patients received 3 L/min of inhaled oxygen, and a sole remifentanil infusion was started with 0.25 microg/kg/min. Remifentanil was adjusted as needed for pain relief (in steps of 0.05 microg/kg/min) and finished after the last puncture. Dosage requirements, vital functions, oxygen saturation (as achieved by pulse oximetry, psO(2)), adverse drug effects and the level of sedation (LOS 1-5; 1 = asleep/unarousable, 4 = calm/awake) were recorded. Remifentanil plasma concentrations were achieved by STANPUMP pharmacokinetic simulation. Data are presented as mean +/- SD.

RESULTS

A total of 50 women (31.8 +/- 5.1 yr, 67.3 +/- 14. ASA I or II ) were investigated. Follicular aspiration lasted 10.8+/-5.2 min, and remifentanil was infused for 19.7+/-8.3 min. Dosage requirements were 0.25 microg/kg/min in 70% of all patients, 0.3 microg/kg/min in 22%, 0.2 microg/kg/min in 6%, and 0.4 microg/kg/min in 2% of all cases. Vital signs (baseline, after 1(st) puncture, end of surgery) nearly remained unchanged: heart frequency = 85 +/- 15, 87 +/- 17, 90 +/- 17 bpm, systolic blood pressure = 129 +/- 12, 132 +/- 13, 131 +/- 14 mmHg; respiratory rate = 116 +/- 4, 15 +/- 4 breaths/min; psO(2) = 99 +/- 1, 99 +/- 1, 99 +/- 2%. LOS was 4.0 (all), 3.9 +/- 0.3, 3.9 +/- 0.3. Remifentanil plasma concentrations were 5.0 +/- 1.3 ng/mL at the start, 6.6 +/- 1.3 at the end of surgery and 1.2 +/- 0.5 at PACU arrival. Adverse drug effects: 54% itching, no muscle rigidity. 94% of all women would choose this technique again.

CONCLUSIONS

The sole infusion of remifentanil is a suitable and satisfying single-agent monitored anaesthesia care technique for oocyte retrieval. However, close anaesthetic observation - especially of the respiratory function - is mandatory.

[Portable capnographs in emergency care: a comparison of equipment]

Recently, transportable capnographs fulfilling the practical demands of emergency medicine have become commercially available (NPB-75, sidestream, Nellcor Puritan Bennett; and Tidal Wave, mainstream, Novametrix). A prerequisite for their use is an accuracy as required for clinical purposes (i.e., pCO2 +/- 2 mmHg). Additionally, environmental conditions in emergency medicine (e.g., changes in ambient temperature) should not have a significant impact on accuracy. The objective of this investigation was to analyse the accuracy of the two capnographs. The accuracy of the pCO2 measurement was evaluated under the following conditions: (1) measurement with three gas mixtures of defined concentrations (gas A: 5% CO2, 95% O2; gas B: 5% CO2, 20% O2, 75% N2; gas C: 10% CO2, 90% N2) related to STPD conditions (STPD = Standard Temperature and Pressure, Dry); and (2) exposure to changes in temperature (from +22 degrees C to -20 degrees C, and from -20 degrees C to +22 degrees C) applying the aforementioned 3 gas mixtures (STPD); and (3) in 20 patients manually ventilated with pure oxygen following endotracheal intubation (i.e., BTPS conditions = body temperature and pressure, saturated). Adequacy of the results was compared to the alveolar gas monitor AGM 1304 (Bruel & Kjaer, Copenhagen, Denmark; sidestream) which served as the reference method (providing an accuracy for the alveolar carbon dioxide partial pressure (pACO2) of +/- 1 mmHg). In the 3 dry gas mixtures, mean inaccuracy proved to be +4.5 +/- 4.1, +2.8 +/- 3.7, and +2.2 +/- 7.0 mmHg (gas A, gas B, gas C; STPD) with the Nellcor sidestream device. Using the Novametrix mainstream capnograph the results were found as follows: (1) -1.1 +/- 0.6, +2.9 +/- 0.6, and +5.6 +/- 2.3 mmHg (oxygen compensation enabled); and (2) +0.2 +/- 1.6, +2.2 +/- 0.6, and +3.2 +/- 4.2 mmHg (oxygen compensation disabled). After changing the environmental temperature (-20 degrees C / +22 degrees C), the resulting deviations (gases A-C, STPD) found with the Nellcor device averaged -12 +/- 4% and +15 +/- 3% (Nellcor); with the Novametrix mainstream device the deviations averaged -1 +/- 2% and +1 +/- 1%, and -2 +/- 1% and +1 +/- 1% (oxygen compensation enabled/disabled). Mean inaccuracy of the pCO2 measurement during ventilation of patients with pure oxygen (BTPS) was found to average -0.9 +/- 0.9 (Nellcor), and either +3.9 +/- 0.8 or +2.1 +/- 0.7 mmHg with the Novametrix (oxygen compensation enabled/disabled). Under BTPS conditions, both devices showed an acceptable deviation of the measurement accuracy up to a maximum of +/- 2 mmHg. The higher deviations of the "NPB-75" (Nellcor Puritan Bennett, sidestream) when using dry gas mixtures (STPD) may be explained by the automatic water vapour correction. Under the conditions of low and changing ambient temperature (-20 degrees C, +22 degrees C), only the "Tidal Wave" (Novametrix; mainstream) remained uninfluenced, whereas deviations of -12% and +15% were found with the "NPB-75".

[Pre-analytic errors in the determination of arterial O(2)-partial pressure under hyperoxic conditions]

OBJECTIVE

A variety of influences reduce the validity of the measured oxygen partial pressure (paO(2)). Most errors occur when obtaining the blood sample and preparing it for analysis. Unfortunately, there is great controversy concerning the relevance and extent of these pre-analytic errors. Apart from this, the exact estimation of influencing factors under hyperoxic conditions has been neglected. Therefore, the objective of this study was to assess pre-analytic measuring errors for paO(2) under the condition of hyperoxia as completely as possible and to work out solutions to eliminate these errors.

METHODS

paO(2) analysis was performed on more than 2000 blood samples. Errors analyzed were the technique of sample taking (direct puncture or from an indwelling catheter), aspirated air bubbles (0.05-0.35 ml), time and temperature of sample storage, and the material, size and manufacturer of the analyzing syringe.

RESULTS

The paO(2) was on average 41 mmHg lower in samples taken from the indwelling catheter than by direct puncture. An air bubble size of 0.1-0.25 ml caused a decrease of 17-41 mmHg. Storage time of 2 min accounted for an paO(2) reduction of 6-67 mmHg depending on the type of syringe used. Glass syringes turned out to be more accurate than plastic syringes. The best results were obtained not from commercial "blood gas syringes" but from a simple plastic injection syringe. For all pre-analytic errors correction factors were established.

CONCLUSION

All pre-analytic errors investigated caused a significant paO(2) decrease. Even an ideal procedure (almost no air bubble, short storage on ice) contributes a significant error. Only the appropriate correction factors as calculated from this study for routine use lead to the correct results. If they are not taken into account the paO(2) values will be falsely low, potentially leading to misinterpretation and misjudgement of a patient's condition.

[Evaluation of lactate measurement in blood and plasma with biosensor technology: a comparison of methods]

The introduction of biosensor technology for near bedside measurement of plasma lactate concentrations has been a promising step for critical care profiling. However, methodological drawbacks and relevant inaccuracy have been reported. With the advent of a new biosensor (Chiron Diagnostics) and a revised NOVA Biomedical device, accuracy was expected to be improved. The goal of the present investigation was to evaluate the accuracy of both methods.

METHODS

Two devices (System 860, Chiron Diagnostics; StatProfile 9, NOVA Biomedical) were simultaneously analysed using 9 biosensors in both fresh frozen plasma and citrated whole blood. The results were compared with an established photometric method (Lactat PAP, Analyticon). Measurements were performed as duplicates (n = 1120) before and after the addition of 1 molar sodium lactate solution (2-24 mmol/L). For the estimation of between-day precision commercially available aqueous and serum-based quality controls were analysed daily over a period of 60 days.

RESULTS

Reproducibility in blood was 2.6 +/- 2.8% (Chiron), 4.1 +/- 4.0% (NOVA) and 1.5 +/- 2.1% (Analyticon), in plasma respectively 2.1 +/- 2.4%, 2.1 +/- 2.9% and 1.0 +/- 1.1%. Mean inaccuracy in plasma presented to be -0.2 +/- 16.4% (plasma) and +7.2 +/- 13.1% (blood) for Chiron, +9.4 +/- 18.4% and +18.7 +/- 16.7% for NOVA, and -37.8 +/- 18.2% and -27.5 +/- 17.6% for Analyticon. Calculated between-day-precision (variation coefficients mean values) was 11.5 +/- 4.9% (Chiron) and 14.0 +/- 5.9% (NOVA).

CONCLUSION

Although accuracy of lactate concentrations obtained with biosensor technology has improved (mean 0-18%), the variability of the results still poses a problem (mean 13-18%). Therefore, from the methodological point of view, interpretation of a single lactate value requires caution when applying to the critically ill, particularly with view to threshold values, and should be considered vis-à-vis other options.

[Remifentanil in gynecologic laparoscopy. A comparison of consciousness and circulatory effects of a combination with desflurane and propofol]

OBJECTIVES

Rapid post-anaesthetic awakening and low hypnotic potency are two characteristic properties of the new opioid remifentanil. For clinical use remifentanil must be combined with another anaesthetic agent. Propofol is well-established for ambulatory anaesthesia, however, the properties of desflurane (low blood-gas solubility, rapid elimination) suggest this volatile anaesthetic to be a comparable alternative, particularly if rapid awakening is desired. The present study was designed to compare emergence times and haemodynamics for a combination of remifentanil wich hypnotic concentrations of either propofol or desflurane.

METHODS

Gynaecological patients, scheduled for elective laparoscopy, were studied at random. After oral premedication with diazepam 0.08-0.12 mg/kg, anaesthesia was induced identically in both groups: remifentanil bolus (1 microgram/kg), start of remifentanil infusion (0.5 microgram/kg/min), followed by propofol (approx. 2 mg/kg) and cisatracurium (0.1 mg/kg). For maintenance of anaesthesia remifentanil (0.25 microgram/kg/min) was combined with either desflurane (0.5 MAC = 3.0 vol%) or propofol (6 mg/kg/h). With termination of surgery anaesthetic delivery was discontinued simultaneously and recovery times were recorded. Heart rate and non-invasive blood pressure were recorded at defined points of interest.

RESULTS

In total, 40 patients (desflurane n = 20, propofol n = 20) were studied in comparable groups. For both regimens, emergence after remifentanil-based anaesthesia was remarkably rapid between unconsciousness and complete recovery: In mean only 60 s elapsed from the onset of spontaneous breathing to the moment when patients could clearly state their name. In comparison, recovery times were significantly shorter after remifentanil-desflurane than after remifentanil-propofol: time to spontaneous ventilation 6.4 +/- 2.8 vs. 9.6 +/- 3.9 min (mean +/- SD, p = 0.01); extubation 6.7 +/- 2.8 vs. 9.8 +/- 4.0 min (p = 0.02) and arrival at PACU 11.1 +/- 3.4 vs. 14.7 +/- 4.2 min (p = 0.005). The courses of heart rate (HR) and mean arterial pressure (MAP) were mostly similar in both groups with only minimal or moderate cardiocirculatory reactions during intubation or start of surgery.

CONCLUSIONS

Remifentanil in combination with either desflurane or propofol, used for general anaesthesia during gynaecological laparoscopy, will facilitate a smooth haemodynamic course as well as a rapid emergence thereafter. Recovery times after remifentanil-based anaesthesia are significantly shorter with 3.0 vol% of desflurane than with 6 mg/kg/h propofol. Thus, desflurane appears to be a well-suited adjunct to remifentanil and an ideal alternative to propofol, if rapid recovery is required. Differences are best explained by the pharmacological properties of both coanaesthetics and their applied dosages.

[Ondansetron. Prophylaxis and therapy of nausea and vomiting following major gynecologic procedures. Results of a national multicenter study]

This investigation was conducted as a national multicenter study to evaluate effectiveness and safety of prophylactic and therapeutic ondansetron for postoperative nausea and vomiting (PONV) in major gynaecological surgery.

METHODS

387 patients were randomised to receive either ondansetron 8 mg or placebo i.v. prior to anaesthesia induction. Anaesthesia was performed with a volatile anaesthetic, nitrous oxide and opioids. Established PONV was treated with ondansetron 4 mg i.v. Postoperative evaluation included time, duration and severeness of nausea and vomiting in the first 24 h after the operation.

RESULTS

In the study period the incidence of emesis was 35% after prophylactic ondansetron and 58% after placebo (p < 0.01). Nausea occurred in 49% and 64% respectively (p < 0.01). 28% after prophylactic ondansetron and 48% after placebo required ondansetron therapy (p < 0.01). The number of adverse events was small in total and comparable for both groups.

CONCLUSION

Our investigation proves the efficiency of ondansetron 8 mg prior to induction of anaesthesia in preventing PONV. Furthermore, our results demonstrate the safety of the drug for prophylaxis and therapy.

Long-term postoperative cognitive dysfunction in the elderly ISPOCD1 study. ISPOCD investigators. International Study of Post-Operative Cognitive Dysfunction

BACKGROUND

Long-term postoperative cognitive dysfunction may occur in the elderly. Age may be a risk factor and hypoxaemia and arterial hypotension causative factors. We investigated these hypotheses in an international multicentre study.

METHODS

1218 patients aged at least 60 years completed neuropsychological tests before and 1 week and 3 months after major non-cardiac surgery. We measured oxygen saturation by continuous pulse oximetry before surgery and throughout the day of and the first 3 nights after surgery. We recorded blood pressure every 3 min by oscillometry during the operation and every 15-30 min for the rest of that day and night. We identified postoperative cognitive dysfunction with neuropsychological tests compared with controls recruited from the UK (n=176) and the same countries as study centres (n=145).

FINDINGS

Postoperative cognitive dysfunction was present in 266 (25.8% [95% CI 23.1-28.5]) of patients 1 week after surgery and in 94 (9.9% [8.1-12.0]) 3 months after surgery, compared with 3.4% and 2.8%, respectively, of UK controls (p<0.0001 and p=0.0037, respectively). Increasing age and duration of anaesthesia, little education, a second operation, postoperative infections, and respiratory complications were risk factors for early postoperative cognitive dysfunction, but only age was a risk factor for late postoperative cognitive dysfunction. Hypoxaemia and hypotension were not significant risk factors at any time.

INTERPRETATION

Our findings have implications for studies of the causes of cognitive decline and, in clinical practice, for the information given to patients before surgery.