Norbert Roewer

A simplified Risk score for predicting postoperative nausea and vomiting : Conclusions from Cross-validations between two centers

BACKGROUND Recently, two centers have independently developed a risk score for predicting postoperative nausea and vomiting (PONV). This study investigated (1) whether risk scores are valid across centers and (2) whether risk scores based on logistic regression coefficients can be simplified without loss of discriminating power. METHODS Adult patients from two centers (Oulu, Finland: n = 520, and Wuerzburg, Germany: n = 2202) received inhalational anesthesia (without antiemetic prophylaxis) for various types of surgery. PONV was defined as nausea or vomiting within 24 h of surgery. Risk scores to estimate the probability of PONV were obtained by fitting logistic regression models. Simplified risk scores were constructed based on the number of risk factors that were found significant in the logistic regression analyses. Original and simplified scores were cross-validated. A combined data set was created to estimate a potential center effect and to construct a final risk score. The discriminating power of each score was assessed using the area under the receiver operating characteristic curves. RESULTS Risk scores derived from one center were able to predict PONV from the other center (area under the curve = 0.65-0.75). Simplification did not essentially weaken the discriminating power (area under the curve = 0.63-0.73). No center effect could be detected in a combined data set (odds ratio = 1.06, 95% confidence interval = 0.71-1.59). The final score consisted of four predictors: female gender, history of motion sickness (MS) or PONV, nonsmoking, and the use of postoperative opioids. If none, one, two, three, or four of these risk factors were present, the incidences of PONV were 10%, 21%, 39%, 61% and 79%. CONCLUSIONS The risk scores derived from one center proved valid in the other and could be simplified without significant loss of discriminating power. Therefore, it appears that this risk score has broad applicability in predicting PONV in adult patients undergoing inhalational anesthesia for various types of surgery. For patients with at least two out of these four identified predictors a prophylactic antiemetic strategy should be considered.

A risk score to predict the probability of postoperative vomiting in adults.

Background: The aim of this study was to identify factors most relevant for postoperative vomiting (PV) and to develop a risk score to predict the probability of PV.

How to study postoperative nausea and vomiting.

Anesthesiological journals are flooded by innumerable studies of postoperative nausea and vomiting (PONV). Nevertheless, PONV remains a continuing problem with an average incidence of 20–30%. This paper should provide essential information for the design, conduct, and presentation of these studies. It should also increase comparability among future studies and help clinicians in assessing and reading the literature on PONV.

Pharmacological treatment of postoperative shivering: a quantitative systematic review of randomized controlled trials.

Shivering is a frequent complication in the postoperative period. The relative efficacy of interventions that are used for the treatment of postoperative shivering is not well understood. We performed a systematic search (MEDLINE, EMBASE, Cochrane Library, hand searching, all languages, to August, 2000) for full reports of randomized comparisons of any pharmacological antishivering intervention (active) with placebo (control) in the postoperative period. Dichotomous data on absence of further shivering after treatment and adverse effects were extracted from original reports. Relative risk (RR) and number-needed-to-treat (NNT) were calculated with 95% confidence interval (CI) using a fixed effect model. Data from 20 trials (944 adults received an active intervention, 413 were controls) were analyzed. Antishivering efficacy depended on the active regimen and the length of follow-up. Efficacy with meperidine 25 mg, clonidine 150 &mgr;g, ketanserin 10 mg, and doxapram 100 mg was reported in at least three trials; all were significantly more effective than control. After 1 min, the NNT of meperidine 25 mg for no further shivering compared with placebo was 2.7 (RR, 6.8; 95% CI, 2.5–18.5). After 5 min, the NNT of meperidine 25 mg was 1.3 (RR, 9.6; 95% CI, 5.7–16), the NNT of clonidine 150 &mgr;g was 1.3 (RR, 6.8; 95% CI, 3.3–14.2), the NNT of doxapram 100 mg was 1.7 (RR 4.0; 95% CI, 2.4–6.5), and the NNT of ketanserin 10 mg was 2.3 (RR 3.1; 95% CI, 1.9–5.1). After 10 min, the NNT of meperidine 25 mg was 1.5 (RR 4.0; 95% CI, 2.5–6.2). After 15 min, the NNT of ketanserin 10 mg was 3.3 (RR 1.5; 95% CI, 1.2–1.9). Long-term outcome data were lacking. There were not enough data for alfentanil, fentanyl, morphine, nalbuphine, lidocaine, magnesium, metamizol, methylphenidate, nefopam, pentazocine, and tramadol to draw meaningful conclusions. Reporting of adverse drug reactions was sparse. Fewer than two shivering patients need to be treated with meperidine 25 mg, clonidine 150 &mgr;g, or doxapram 100 mg for one to stop shivering within 5 min who would have continued to shiver had they all received a placebo.

Whole-Body Multislice Computed Tomography as the First Line Diagnostic Tool in Patients With Multiple Injuries : The Focus on Time

OBJECTIVE Whole-body multislice helical computed tomography (MSCT) becomes increasingly important as a diagnostic tool in patients with multiple injuries. We describe time requirement of two different diagnostic approaches to multiple injuries one with whole-body-MSCT (MSCT Trauma-Protocol) as the sole radiologic procedure and one with conventional use of radiography, combined with abdominal ultrasound and organ focused CT (Conventional-Trauma-Protocol). METHODS Observational study with retrospective analysis of time requirements for resuscitation, diagnostic workup and transfer to definitive treatment after changing from conventional to MSCT Trauma-Protocol. Group I: data from trauma patients imaged with whole-body MSCT. Group II: data of trauma patients investigated with conventional trauma protocol before the introduction of MSCT-Trauma-Protocol. RESULTS The complete diagnostic workup in group I (n = 82) was finished after 23 minutes (17-33 minutes) [median; interquartile range (IQR)] and after 70 minutes (IQR, 56-85) in group II (n = 79). The definitive management plan based on a completed diagnostic workup was devised after 47 minutes (IQR, 37-59) in group I and after 82 minutes (IQR, 66-110) in group II. CONCLUSION A whole-body MSCT-based diagnostic approach to multiple injuries might shorten the time interval from arrival in the trauma emergency room until obtaining a final diagnosis and management plan in patients with multiple injuries and might, therefore, contribute to improvements in patient care.

Dimenhydrinate for prophylaxis of postoperative nausea and vomiting: a meta‐analysis of randomized controlled trials

Background: Diphenhydramine and its theoclate salt dimenhydrinate are traditional antiemetics still in use. However, so far the quantitative effect of dimenhydrinate in the prophylaxis of postoperative nausea and vomiting (PONV) has not been evaluated systematically.

The Efficacy and Safety of Transdermal Scopolamine for the Prevention of Postoperative Nausea and Vomiting: A Quantitative Systematic Review

The role of scopolamine administered via transdermal therapeutic systems in the prevention of postoperative vomiting, nausea, and nausea and vomiting is unclear. We performed a systematic search for full reports of randomized comparisons of transdermal scopolamine with inactive control. Dichotomous data were extracted. In the meta-analysis, relative risks and numbers-needed-to-treat/harm were calculated with 95% confidence intervals (CI). In 23 trials, 979 patients received transdermal scopolamine, and 984 patients received placebo. Sensitivity analyses were performed using restricted data for truncated control event rates (40%–80%) and for large trials. With these data, the relative risks for postoperative vomiting (five reports), nausea (five reports), nausea and vomiting (eight reports), and rescue treatment (three reports) were 0.69 (95% CI, 0.58–0.82), 0.69 (95% CI, 0.54–0.87), 0.76 (95% CI, 0.66–0.88), and 0.68 (95% CI, 0.54–0.85), respectively. This means that of 100 patients who receive transdermal scopolamine, approximately 17 will not experience postoperative vomiting who would have done so had they all received a placebo. However, 18 of 100 patients will have visual disturbances, eight will report dry mouth, two will report dizziness, one will be classified as being agitated, and 1–13 patients who are prescribed transdermal scopolamine will not use it correctly. The timing of application does not alter efficacy.

The discriminating power of a risk score for postoperative vomiting in adults undergoing various types of surgery

Background: Recently, we have demonstrated that the probability of postoperative vomiting (PV) following ENT surgery with inhalational anaesthetics can be predicted using a risk score. This score is based on gender, age, smoking status, history of motion sickness or postoperative nausea and vomiting and the duration of anaesthesia. Therefore, it is of interest whether this score is also accurate in predicting PV in patients undergoing different types of surgery.

Sevoflurane-induced preconditioning protects against cerebral ischemic neuronal damage in rats

In the present study, we tested the ability of sevoflurane to induce early and late preconditioning against ischemic neuronal injury using an in vivo model of global cerebral ischemia in the rat. Seven-minute global ischemia was induced by cardiac arrest, followed by resuscitation and recovery for 7 days. Hippocampal slices were then prepared and the amplitude of extracellularly recorded, orthodromically evoked, CA1 population spikes (neuronal function) was quantified. Rats were preconditioned for 30 min with 1.0 minimum alveolar concentration (MAC) of sevoflurane once or on 4 consecutive days, 15 min (single exposure, early) or 24 h (four exposures, late preconditoning) prior to cardiac arrest. After early or late preconditioning, sevoflurane reduced ischemic neuronal damage from 43 +/- 3% [sham rats, (mean +/- SEM)] to 30 +/- 3% and 35 +/- 4%, respectively. Histopathology demonstrated a preserved morphology of the CA1 region of preconditioned rats, whereas pyknosis was present in control and sham-treated rats. Sevoflurane-induced preconditioning confers neuroprotection during an early as well as late time window.

Ultrasound-guided arterial cannulation in infants improves success rate.

Background and objective: In small children, the placement of arterial catheters can be technically challenging for even the most experienced anaesthetist. We investigated whether ultrasound imaging would improve the success rate and reduce time demand and complications of radial artery cannulation. Method: In this prospective randomized study, we performed radial artery cannulation in 30 small children (age 40 ± 33 months) using two different techniques for localization of the vessel. In Group 1 (n = 15), the traditional palpation method was used, while in Group 2 (n = 15) cannulation was directed by vascular ultrasound imaging. In addition, we used ultrasound to determine the cross‐sectional area of the radial artery with and without dorsiflexion. For statistical analysis, the non‐parametric U‐test for non‐paired data and the Wilcoxon signed rank sum test for paired data were used. Differences were considered significant, when P < 0.05. Results: Ultrasound‐guided puncture was successful in all children of Group 2 compared to only 12 of 15 (80%) children in Group 1. Fewer attempts with the imaging technique were required than with the traditional technique (20 vs. 34, P < 0.05). Dorsiflexion significantly reduced the mean cross‐sectional area of the artery by 19%. Conclusion: The current pilot study suggests that ultrasound guidance is appropriate for radial artery catheter insertion, sharing many of the benefits of ultrasound‐guided central vein catheter insertion.