The influence of ondansetron on the analgesic effect of acetaminophen after laparoscopic hysterectomy.

The 5-HT(3) antagonists tropisetron and granisetron have been shown to block the analgesic effect of acetaminophen in healthy volunteers. To study the interaction between ondansetron and acetaminophen in women undergoing laparoscopic hysterectomy, we randomized 134 patients into three groups to receive acetaminophen-placebo (AP), acetaminophen-ondansetron (AO), or placebo-placebo (PP). One gram of intravenous acetaminophen or placebo was administered at the induction of anesthesia and every 6 h thereafter for 24 h, and 4 mg of ondansetron or placebo was administered at the end of surgery. Pain control was provided by patient-controlled analgesia (PCA)-oxycodone. Acetaminophen (as compared to placebo) in periodic doses starting at induction of anesthesia reduced the total dosage of oxycodone required over 0-24 h (P = 0.031), but ondansetron given at the end of the surgery had no impact on the analgesic effect of acetaminophen (P = 0.723). The Numeric Rating Scale (NRS) scores for pain were similar whether ondansetron or placebo was administered at the end of the surgery. Therefore, it may be concluded that in women undergoing laparoscopic hysterectomy, the administration of periodic doses of intravenous acetaminophen (as compared to placebo) starting at induction of anesthesia reduces the total dose requirement of oxycodone, and a concomitant dose of a 5-HT(3) antagonist such as ondansetron at the end of the surgery does not block the analgesic effect of acetaminophen.

Propofol versus alfentanil to prevent movement responses during uterine curettage.

BACKGROUND: Propofol anaesthesia is frequently associated with movement responses in non-paralysed patients. Opioids decrease the probability of movement during noxious stimulation. Heart rate variability and frontal electromyography (EMG), which are related to subcortical functions, may be more closely related than surface electroencephalography (EEG) to movement responses to noxious stimulation. METHODS: Eighty-two patients scheduled for uterine dilatation and curettage were randomized to receive at the first intra-operative movement either a supplemental alfentanil bolus, 0.5 mg intravenously, or a supplemental propofol bolus, 0.7 mg/kg intravenously. The incidences of recurring movement during the procedure were compared between the two groups. The associations of a measure of heart rate variability (Anemon index), heart rate, EMG and two EEG variables with movement responses were evaluated. RESULTS: The incidences of recurring movement were 73% and 38% in the alfentanil and propofol groups, respectively [difference, 35%; 95% confidence interval, 9-56%; P= 0.014 between the groups). The Anemon index, heart rate, EMG and surface EEG variables displayed mainly reactive associations with movement responses. CONCLUSION: During uterine curettage under propofol-alfentanil-nitrous oxide anaesthesia, a propofol bolus of 0.7 mg/kg was more effective in preventing the recurrence of movement responses than an alfentanil bolus of 0.5 mg. Several physiological variables may be used to track significant arousal reactions, but not to predict them.

Corticosteroids combined with continuous veno-venous hemodiafiltration for treatment of hantavirus pulmonary syndrome caused by Puumala virus infection.

Reported here are two cases of hantavirus pulmonary syndrome caused by Puumala virus infection, which rapidly resolved after initiation of corticosteroid treatment combined with continuous veno-venous hemodiafiltration. These cases emphasize the role of the inflammatory response in the pathogenesis of hantavirus pulmonary syndrome.

Novel multiparameter approach for measurement of nociception at skin incision during general anaesthesia.

BACKGROUND: Direct indicators for the evaluation of the nociceptive-anti-nociceptive balance during general anaesthesia do not exist. The aim of this study was to combine physiological parameters to obtain such an indicator. METHODS: Fifty-five females scheduled for surgery under general anaesthesia combining target-controlled infusions of propofol and remifentanil were studied. Propofol was given to maintain state entropy (SE) at 50 and remifentanil was targeted at 1, 3 or 5 ng ml(-1). The patients' reactions and clinical signs of nociception, remifentanil levels and estimation of noxious intensity of incision were combined into a clinical score [Clinical Signs-Stimulus-Antinociception (CSSA)] to evaluate the nociceptive-anti-nociceptive balance. ECG, photoplethysmography (PPG), response entropy (RE) and SE were recorded from 60 s before to 120 s after skin incision. Differences between post- and pre-incision values of heart rate variability (HRV), PPG and pulse transition time related parameters were analysed off-line to evidence the best predictors of CSSA. Those best predictors of CSSA served to develop a response index of nociception (RN), scaled from 0 to 100. This index was further tested in 10 additional patients. RESULTS: HRV, RE, RE-SE and PPG variability were the best predictors of CSSA. The prediction probability of RN at predicting CSSA was 0.78. RN response was higher after larger incision, in movers and with lower remifentanil concentrations. CONCLUSIONS: The empirically developed algorithm of RN leads to an index that seems to adequately estimate the nociceptive-anti-nociceptive balance at skin incision during general anaesthesia. In the future, CSSA may serve as a reference for studies investigating methods aimed at evaluating this pharmacodynamic component of anaesthesia.

EEG spectral entropy, heart rate, photoplethysmography and motor responses to skin incision during sevoflurane anaesthesia.

BACKGROUND: Analgesia is a part of balanced anaesthesia, but direct indicators of nociception do not exist. We examined the relationship between motor reactions and physiological variables during skin incision in sevoflurane anaesthesia and hypothesized that nociception could be detected and graded by significant changes in these variables. METHODS: Thirty-one women scheduled for abdominal hysterectomy participated in the study. Anaesthesia was induced with fentanyl (1 microg kg(-1)), propofol (1 mg kg(-1)) and sevoflurane. Skin incision was performed 14 min after induction during 1.6% end-tidal sevoflurane anaesthesia without neuromuscular blockade. Electrocardiography (ECG), photoplethysmography (PPG) and electroencephalography (EEG) were registered, and a range of variables was computed from these signals. The postincision values, normalized with respect to their preincision values, of movers vs. non-movers were compared. The variables showing significant differences between movers and non-movers were used to develop a logistic regression equation for the classification of patients into movers or non-movers. RESULTS: Twenty-six patients were eligible for analysis, and 12 (46%) displayed a motor reaction to skin incision (movers). Many ECG, PPG and EEG-related variables showed significant differences between the pre- and postincision periods. The best classification performance, assessed by leave-one-out cross-validation, between movers and non-movers was achieved with the combination of response entropy of EEG, RR-interval and PPG notch amplitude. The corresponding equation yielded 96% correct classification with 90% sensitivity and 100% specificity. The classification performance of any single variable alone was considerably worse. CONCLUSION: Combination of information from different sources may be required for monitoring the adequacy of analgesia during anaesthesia.

Are electrocardiogram electrodes acceptable for electroencephalogram bispectral index monitoring?

BACKGROUND: The monitoring of electroencephalogram bispectral index (EEG-BIS) during anaesthesia reduces anaesthetic use and improves recovery. However, it also increases the direct costs of anaesthesia due to the need for special EEG electrodes. In the present study we tested the feasibility of less expensive electrocardiogram (ECG) electrodes for EEG-BIS monitoring. METHODS: In the first part of the study we compared skin-electrode impedances when EEG electrodes were used after alcohol swab pretreatment of skin to impedances when ECG electrodes were used after alcohol swab pretreatment with or without skin abrasion paste. In the second part of the study we evaluated the difference in parallel BIS values collected with two BIS monitors, using either ECG electrodes or EEG electrodes. In the third part of the study we compared parallel BIS values collected with two sets of EEG electrodes. RESULTS: Skin pretreatment with abrasion paste led to lower impedances with ECG electrodes than did alcohol swab pretreatment of skin with EEG electrodes. When the skin was pretreated with alcohol swab, higher impedances were measured with ECG electrodes than with EEG electrodes. In most patients, BIS values collected with ECG electrodes were also higher than those collected with adhesive EEG electrodes. The difference between parallel BIS values collected with two sets of adhesive EEG electrodes was smaller than the difference between BIS values collected with ECG and EEG electrode sets. CONCLUSION: Low skin-electrode impedances indicating reliable skin-electrode contact can be ensured with inexpensive pregelled ECG electrodes only if the skin is carefully prepared with both abrasion paste and alcohol. When only alcohol pretreatment of skin is used, the BIS values collected with EEG electrodes and ECG electrodes are not equal. EEG-BIS monitoring with pregelled ECG electrodes is recommended only if skin is prepared with abrasion paste before attaching the electrodes.