Ozlem S. Cakmakkaya

Evidence-based analysis of risk factors for postoperative nausea and vomiting

BACKGROUND /st> In assessing a patients risk for postoperative nausea and vomiting (PONV), it is important to know which risk factors are independent predictors, and which factors are not relevant for predicting PONV. METHODS /st> We conducted a systematic review of prospective studies (n>500 patients) that applied multivariate logistic regression analyses to identify independent predictors of PONV. Odds ratios (ORs) of individual studies were pooled to calculate a more accurate overall point estimate for each predictor. RESULTS /st> We identified 22 studies (n=95 154). Female gender was the strongest patient-specific predictor (OR 2.57, 95% confidence interval 2.32-2.84), followed by the history of PONV/motion sickness (2.09, 1.90-2.29), non-smoking status (1.82, 1.68-1.98), history of motion sickness (1.77, 1.55-2.04), and age (0.88 per decade, 0.84-0.92). The use of volatile anaesthetics was the strongest anaesthesia-related predictor (1.82, 1.56-2.13), followed by the duration of anaesthesia (1.46 h(-1), 1.30-1.63), postoperative opioid use (1.39, 1.20-1.60), and nitrous oxide (1.45, 1.06-1.98). Evidence for the effect of type of surgery is conflicting as reference groups differed widely and funnel plots suggested significant publication bias. Evidence for other potential risk factors was insufficient (e.g. preoperative fasting) or negative (e.g. menstrual cycle). CONCLUSIONS /st> The most reliable independent predictors of PONV were female gender, history of PONV or motion sickness, non-smoker, younger age, duration of anaesthesia with volatile anaesthetics, and postoperative opioids. There is no or insufficient evidence for a number of commonly held factors, such as preoperative fasting, menstrual cycle, and surgery type, and using these factors may be counterproductive in assessing a patients risk for PONV.

Who is at risk for postdischarge nausea and vomiting after ambulatory surgery

Background: About one in four patients suffers from postoperative nausea and vomiting. Fortunately, risk scores have been developed to better manage this outcome in hospitalized patients, but there is currently no risk score for postdischarge nausea and vomiting (PDNV) in ambulatory surgical patients. Methods: We conducted a prospective multicenter study of 2,170 adults undergoing general anesthesia at ambulatory surgery centers in the United States from 2007 to 2008. PDNV was assessed from discharge until the end of the second postoperative day. Logistic regression analysis was applied to a development dataset and the area under the receiver operating characteristic curve was calculated in a validation dataset. Results: The overall incidence of PDNV was 37%. Logistic regression analysis of the development dataset (n = 1,913) identified five independent predictors (odds ratio; 95% CI): female gender (1.54; 1.22 to 1.94), age less than 50 yr (2.17; 1.75 to 2.69), history of nausea and/or vomiting after previous anesthesia (1.50; 1.19 to 1.88), opioid administration in the postanesthesia care unit (1.93; 1.53 to 2.43), and nausea in the postanesthesia care unit (3.14; 2.44–4.04). In the validation dataset (n = 257), zero, one, two, three, four, and five of these factors were associated with a PDNV incidence of 7%, 20%, 28%, 53%, 60%, and 89%, respectively, and an area under the receiver operating characteristic curve of 0.72 (0.69 to 0.73). Conclusions: PDNV affects a substantial number of patients after ambulatory surgery. We developed and validated a simplified risk score to identify patients who would benefit from long-acting prophylactic antiemetics at discharge from the ambulatory care center.

Transdermal Scopolamine for the Prevention of Postoperative Nausea and Vomiting: A Systematic Review and Meta-Analysis

BACKGROUND Transdermal scopolamine (TDS) is a potential long-acting prophylactic antiemetic initially developed to prevent motion sickness. TDS is a centrally acting anticholinergic agent that was approved in 2001 by the US Food and Drug Administration for the prevention of postoperative nausea and vomiting (PONV). Although TDS has been reported to be clinically efficacious in the prevention of PONV, several adverse events (AEs), such as sedation, dry mouth, blurred vision, central cholinergic syndrome, and confusion (particularly in elderly patients with mild cognitive impairment), are potential concerns. OBJECTIVE The aim of this study was to explore the efficacy and tolerability of TDS in the prevention of PONV in adults. METHODS A systematic search of PubMed, EMBASE, and the Cochrane Library for randomized controlled trials in adults that compared the effects of TDS and placebo on postoperative nausea, vomiting, and PONV was conducted in March 2009, and an update was conducted in July 2010. Without any language restrictions, a search with the following terms was performed: postoperative, postoperative, postanesthe*, postanaesthe*, post-anesthe*, post-anaesthe*, anesthesia, anaesthesia, surgery, surgeries, surgical, nausea, vomiting, emesis, retching, scopolamine, and hyoscine. Identified studies were then hand-searched for further relevant literature. RESULTS Data from 25 randomized controlled trials were analyzed (N = 3298). In the postanesthesia care unit, TDS was associated with a significantly reduced risk for postoperative nausea compared with placebo (relative risk [RR] = 0.77; 95% CI, 0.61-0.98; P = 0.03). TDS was also associated with a significantly reduced risk for postoperative nausea (RR = 0.59; 95% CI, 0.48-0.73; P < 0.001), postoperative vomiting (RR = 0.68; 95% CI, 0.61-0.76; P < 0.001), and PONV (RR = 0.73; 95% CI, 0.60-0.88; P = 0.001) during the first 24 hours after the start of anesthesia. TDS appeared to be effective compared with placebo in the prevention of postoperative nausea when treatment was initiated the night before (early application) (RR = 0.56; 95% CI, 0.41-0.75; P < 0.001) or on the day of surgery (late application) (RR = 0.61; 95% CI, 0.47-0.79; P < 0.001). TDS was associated with a higher prevalence of visual disturbances at 24 to 48 hours compared with placebo (RR = 3.35; 95% CI, 1.78-6.32). Analyses of confusion and other AEs did not show a significant association with TDS. CONCLUSIONS In this systematic review and metaanalysis, TDS was associated with significant reductions in PONV with both early and late patch application during the first 24 hours after the start of anesthesia. TDS was associated with a higher prevalence of visual disturbances at 24 to 48 hours after surgery, but no other AEs, compared with placebo.

Effect of increased body mass index and anaesthetic duration on recovery of protective airway reflexes after sevoflurane vs desflurane

BACKGROUND Increased BMI may increase the bodys capacity to store potent inhaled anaesthetics, more so with more soluble agents. Accordingly, we asked whether increased BMI and longer anaesthesia prolonged airway reflex recovery. METHODS We measured time from anaesthetic discontinuation until first response to command (T1); from response to command until ability to swallow (T2); and from anaesthetic discontinuation to recovery of ability to swallow (T3) in 120 patients within three BMI ranges (18-24, 25-29, and >or=30 kg m(-2)). All received sevoflurane or desflurane, delivered via an LMA. RESULTS T1 and T3 after sevoflurane exceeded T1 and T3 after desflurane: 6.6 (sd 4.2) vs 4.0 (1.9) min (P<0.001), and 14.1 (sd 8.3) vs 6.1 (2.0) min (P<0.0001). T3 correlated more strongly with BMI after sevoflurane (28 s per kg m(-2), P=0.02) than desflurane (7 s per kg m(-2), P=0.03). Regarding T2, patients receiving sevoflurane with BMI >or=30 kg m(-2) were less often able to swallow 2 min after response to command than were those with BMI 18-24 or 25-29 kg m(-2) (3/20 vs 10/20 or 9/20, P<0.05). Each sevoflurane MAC-hour delayed T3 by 4.5 min (268 s) (R=0.46, P<0.001) whereas each desflurane MAC-hour delayed T3 by 0.2 min (16 s) (R=0.10, P=0.44). CONCLUSIONS Prolonged sevoflurane administration and greater BMI delay airway reflex recovery. The contribution of BMI to this delay is more pronounced after sevoflurane than desflurane.

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.

Ondansetron has similar clinical efficacy against both nausea and vomiting.

Ondansetron is widely believed to prevent postoperative vomiting more effectively than nausea. We analysed data from 5161 patients undergoing general anaesthesia who were randomly stratified to receive a combination of six interventions, one of which was 4 mg ondansetron vs placebo. For the purpose of this study a 20% difference in the relative risks for the two outcomes was considered clinically relevant. Nausea was reduced from 38% (969/2585) in the control to 28% (715/2576) in the ondansetron group, corresponding to a relative risk of 0.74, or a relative risk reduction of 26%. Vomiting was reduced from 17% (441/2585) to 11% (293/2576), corresponding to a relative risk of 0.67, or a relative risk reduction of 33%. The relative risks of 0.67 and 0.74 were clinically similar and the difference between them did not reach statistical significance. We thus conclude that ondansetron prevents postoperative nausea and postoperative vomiting equally well.

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.

General anesthesia for a child with Goldenhar syndrome

SIR—Goldenhar, in 1952, described the classical triad of epibulbar dermoids, preaurical tags and blind fistulas and vertebral anomalies (1). Difficulty in tracheal intubation may result from a combination of mandibular hypoplasia, craniovertebral anomalies, and hemifacial microsomia. Radiological evaluation for mandibular deformity and craniovertebral anomalies is recommended (2). We describe the anesthetic management of a child with Goldenhar syndrome. A 4.5-year-old, 18 kg, girl previously diagnosed with Goldenhar’s Syndrome was scheduled for ectropion surgery. The manifestation of Goldenhar’s syndrome were right sided maxillofacial hypoplasia, mandibular hypoplasia, right microtia, right epibulbar demoid. She had no vertebral abnormalities or cardiac disease. Blood tests and chest radiography were normal. The patient had been operated 2 years previously because of right epibulbar dermoids. There was no information about difficulty in tracheal intubation in this operation. Mouth opening was limited because of the mandibular hypoplasia. Because we suspected that tracheal intubation would be difficult, we decided to anesthetize and intubate the patient without muscle relaxants using propofol and remifentanil. Special attention was paid to the possibility of difficulties in airway management. After preoxygenation, a continuous infusion of remifentanil 1 lÆkgÆmin was started. Anesthesia was induced with propofol 2.0 mgÆkg and maintained with sevoflurane 1% in oxygen. Lung ventilation was achieved via a facemask. Laryngoscopy was performed using a Macintosh 2 blade. First attempt at visualization of the larynx and oral intubation of the trachea was unsuccessful. After the first attempt, it was decided to exchange the curved blade for straight (Miller) blade and use a stylet for a blind technique. A 4.5 mm tracheal tube with a curved stylet was guided in the presumed direction of the glottis. The tube slid off the stylet but would not pass into the trachea. We exchanged the tube for 4.0 mm and the intubation was performed successfully at the next attempt, confirmed by auscultation and capnometry. Anesthesia was maintained with sevoflurane 1 and 50% O2/N2O and the lungs ventilated with volume controlled mechanical ventilation (Cicero, Draeger, Lübeck, Germany). The remifentanil infusion was maintained at 0.15 lÆkgÆmin. Muscle relaxants were not required. Anesthesia, which was uneventful, lasted for 160 min, after which the patient was extubated. The postoperative course was uneventful. Anesthesiologists should be aware of the possibility of difficulty in airway management, cardiovascular and renal disorders and neuromusculer problems in Goldenhar’s syndrome. Evaluation of upper and lower airway obstruction, pulmonary function, laryngeal, renal, cardiac and neurological function is recommended (2). There are previous reports of anesthesia in patient with Goldenhar’s syndrome pointing out difficulties with airway management. A retrograde intubation method was used successfully in a 5-month-old infant with Goldenhar’s syndrome by Cooper and Murray–Wilson (3). Bahk et al. described four different cases of difficult airway including one with Goldenhar’s syndrome. They reported use of a laryngeal mask airway and fiberoptic intubation via the laryngeal mask (4). Sculerati et al. assessed airway management in children with major craniofacial anomalies in a retrospective study (5). They found craniofacial synostosis patients (Crouzon, Pfeifer, or Apert syndrome) had the highest rate of tracheostomy (48%), mandibulofacial dysostoses patients (Treacher collins or Nager syndrome) had the next highest rate (41%) but patients with oculo-auriculovertebral sequence were less likely to undergo tracheostomy (22%). Before anesthetizing this patient, we anticipated that tracheal intubation might be difficult, avoided using muscle relaxants and expected a rapid return of spontaneous ventilation if intubation had failed. Awakening time from remifentanil based anesthesia is significantly faster than inhalational anesthesia alone (6). This method could be considered if there is possibility of difficulty in airway management. Fatis Altintas Ozlem S. Cakmakkaya Department of Anaesthesiology and Reanimation, Cerrahpasa Medical School, University of Istanbul, Istanbul, Turkey (email: sercakmakkaya@hotmail.com or serpilcakmakkaya@yahoo.com)

Anesthetic management of a child with Arnold–Chiari malformation and Klippel–Feil syndrome

1 Tariq M, Beg MH. A foreign body in the bronchus still presents problems. Int J Clin Pract 1999; 53: 81–82. 2 Brett CM, Zwass MS. Eyes ears nose throat and dental surgery. In: Gregory GA, ed. Pediatric Anesthesia, 4th edn. Philadelphia, PA: Churchill Livingstone, 2002: 663–705. 3 Bossoe HH, Boe J. Broken tracheostomy tube as a foreign body. Lancet 1960; 1: 1006–1007. 4 Sood RK. Fractured tracheostomy tube. J Laryngol Otol 1973; 87: 1033–1034. 5 Kemper BI, Rosica N, Myers EN et al. Migration of the inner cannula. An unusual foreign body. Eye Ear Nose Throat Mon 1972; 51: 257–258. 6 Kakar PK, Saharia PS. An unusual foreign body in the tracheobronchial tree. J Laryngol Otol 1972; 86: 1155–1157. 7 Ward CF, Benumof JL. Anesthesia for airway foreign body extraction in children. Anesth Rev 1977; 4: 13.

Anesthetic management in a child with deletion 9p syndrome

1.69 lgÆkgÆh and 1.23 lgÆkgÆh of fentanyl for the patient receiving wound infiltration only and for the patient receiving caudal morphine with local infiltration, respectively. In summary, we present this case of pediatric liver transplantation with local anesthetic wound infiltration for postoperative pain control, and compare it with a previous report of caudal morphine with local anesthetic infiltration of the wound. Early extubation aids in early mobilization and graft perfusion, and may improve the overall success of the operation (4). No conclusions can be drawn regarding the superiority of caudal morphine vs local wound infiltration alone, but supplemental analgesic techniques in pediatric liver transplant patients may allow for reduced administration of narcotics and help facilitate early extubation and recovery. The decision to use supplemental local anesthetics must take into consideration the viability of the donor liver, potential for toxicity, coagulation status and whether the child is a candidate for early extubation. Tae W. Kim* Calvin C. Chan† *Department of Anesthesiology and Pediatrics, Baylor College of Medicine, Texas Children’s Hospital, Houston, TX, USA †The University of Texas, Health Science Center, Houston, TX, USA (email: twkim@bcm.tmc.edu).