The effects of droperidol and ondansetron on dispersion of myocardial repolarization in children

[Postoperative nausea and vomiting-recommendations for its prevention and therapy in paediatric medicine]

Post-operative nausea and/or vomiting (PONV/POV) are among the biggest problems occurring in the paediatric recovery room and in the course of the following post-operative period. Apart from pain and emergence delirium, PONV is one of the main causes of post-operative discomfort in children. The DGAI Scientific Working Group on Paediatric Anaesthesia already worked out recommendations for the prevention and treatment of PONV in children years ago. These recommendations have now been revised by a team of experts, the current literature has been reviewed, and evidence-based core recommendations have been consented. Key elements of the new recommendations consist of effective individual measures for prevention and therapy, next to the implementation of a fixed dual prophylaxis in the clinical routine applicable to all children ≥ 3 years of age.

A pharmacogenomic investigation of the cardiac safety profile of ondansetron in children and pregnant women

BACKGROUND

Ondansetron is a highly effective antiemetic for the treatment of nausea and vomiting. However, this medication has also been associated with QT prolongation. Pharmacogenomic information on therapeutic response to ondansetron exists, but no investigation has been performed on genetic factors that influence the cardiac safety of this medication.

METHODS

Three patient groups receiving ondansetron were recruited and followed prospectively (pediatric post-surgical patients n = 101; pediatric oncology patients n = 98; pregnant women n = 62). Electrocardiograms were conducted at baseline, and 5- and 30-min post-ondansetron administration, to determine the effect of ondansetron treatment on QT interval. Pharmacogenomic associations were assessed via analyses of comprehensive CYP2D6 genotyping and genome-wide association study data.

RESULTS

In the entire cohort, 62 patients (24.1%) met the criteria for prolonged QT, with 1.2% of the cohort exhibiting unsafe QT prolongation. The most significant shift from baseline occurred at five minutes post-ondansetron administration (P = 9.8 × 10^-4). CYP2D6 activity score was not associated with prolonged QT. Genome-wide analyses identified novel associations with a missense variant in TLR3 (rs3775291; P = 2.00 × 10^-7) and a variant linked to the expression of SLC36A1 (rs34124313; P = 1.97 × 10^-7).

CONCLUSIONS

This study has provided insight into the genomic basis of ondansetron-induced cardiac changes and has emphasized the importance of genes that have been implicated in serotonin-related traits. These biologically-relevant findings represent the first step towards understanding this adverse event with the overall goal to improve the safety of this commonly used antiemetic medication.

The effect of oral ondansetron on QT interval in children with acute gastroenteritis; a retrospective observational study

Background

In mildly to moderately dehydrated patients with acute gastroenteritis (AGE), oral rehydration therapy (ORT) is the treatment of choice. Though ondansetron is a very effective antiemetics and leads to succeed ORT, there have been reports QT prolongation in patients using it. We investigated the effect of oral ondansetron on QT interval in mildly to moderately dehydrated children with AGE.

Methods

This retrospective observational study was conducted in a single pediatric emergency department (ED) of a tertiary university hospital. We collected the medical records of patients with a primary diagnosis of AGE who received oral ondansetron and underwent an electrocardiogram between January 2017 and June 2018. A pediatric emergency physician calculated the corrected QT interval (QTc) by Bazett’s method, and the calculations were reviewed by a pediatric cardiologist. QTc values before (preQTc) and after (postQTc) ondansetron administration were analyzed. ΔQTc was calculated as the change from preQTc to postQTc. We also investigated any cardiac complications from oral ondansetron.

Results

Total 80 patients were included. The mean age of the patients was 53.31 ± 32.42 months, and 45% were male. The mean dose of oral ondansetron was 0.18 ± 0.04 mg/kg. The mean interval from administration of ondansetron to performance of the electrocardiogram was 65 ± 26 min. The mean preQTc was 403.3 ± 24.0 ms, and the mean postQTc was 407.2 ± 26.7 ms. Two patients had a preQTc ≥460 ms, and one patient had a postQTc ≥460 ms. ΔQTc was ≥30 ms in seven patients (8.8%). No ΔQTc was ≥60 ms. No pre- or postQTc was ≥500 ms. No patient had a fatal cardiac arrhythmia after taking ondansetron.

Conclusion

Oral administration of a single dose of ondansetron in children with AGE did not cause high-risk QTc prolongation or fatal arrhythmia.

Postoperative Nausea and Vomiting in Pediatric Patients

Postoperative nausea and vomiting (PONV), postoperative vomiting (POV), post-discharge nausea and vomiting (PDNV), and opioid-induced nausea and vomiting (OINV) continue to be causes of pediatric morbidity, delay in discharge, and unplanned hospital admission. Research on the pathophysiology, risk assessment, and therapy for PDNV, OINV and pain therapy options in children has received increased attention. Multimodal pain management with the use of perioperative regional and opioid-sparing analgesia has helped decrease nausea and vomiting. Two common emetogenic surgical procedures in children are adenotonsillectomy and strabismus repair. Although PONV risk factors differ between adults and children, the approach to decrease baseline risk is similar. As PONV and POV are frequent in children, antiemetic prophylaxis should be considered for those at risk. A multimodal approach for antiemetic and pain therapy involves preoperative risk evaluation and stratification, antiemetic prophylaxis, and pain management with opioid-sparing medications and regional anesthesia. Useful antiemetics include dexamethasone and serotonin 5-hydroxytryptamine-3 (5-HT3) receptor antagonists such as ondansetron. Multimodal combination prophylactic therapy using two or three antiemetics from different drug classes and propofol total intravenous anesthesia should be considered for children at high PONV risk. "Enhanced recovery after surgery" protocols include a multimodal approach with preoperative preparation, adequate intravenous fluid hydration, opioid-sparing analgesia, and prophylactic antiemetics. PONV guidelines and management algorithms help provide effective postoperative care for pediatric patients.

The effects of ondansetron versus dexamethasone on electrocardiographic markers of ventricular repolarization in children undergoing cochlear implant

INTRODUCTION

Congenital hearing loss is associated with cardiac rhythm disturbances namely long Q-T syndrome. This study was designed to investigate the effect of anti-emetic doses of ondansetron and dexamethasone on ECG recordings in children undergoing cochlear implant surgery.

METHODS

Sixty-three pediatric patients scheduled for elective cochlear implantation were enrolled in the study. Two patients were excluded as their baseline ECG showed long QT syndrome. Anesthesia was induced with fentanyl, propofol and atracurium and maintained with propofol. Dexamethasone 0.1 mg.kg^-1or ondansetron 0.2 mg.kg^-1was randomly administered for the participants approximately 30 min before the end of surgery. ECG recording was performed 15 min after induction of anesthesia and 15 min after dexamethasone/ondansetron administration. RR interval, QRS duration, QT interval, and Tp-e interval were measured by a blinded cardiologist.

RESULTS

Ondansetron resulted in no significant changes in RR, JTc and QTc intervals; while prolongedTp-e interval. Multivariable logistic regression analysis showed that use of ondansetron was an independent predictor of QTc prolongation after adjustment for age, gender and baseline QTc (OR = 17.94, CI 95% 1.97-168.70, p = 0.011). The incidence of postoperative retching/vomiting in ondansetron group was significantly lower than dexamethasone group. (3.2% vs. 26.7%, p = 0.011).

CONCLUSION

The risk of arrhythmias with the use of ondansetron in otherwise healthy candidates of cochlear implant is very low. However, the drug may induce significant changes in ECG parameters. The clinical significance of these changes in patients with cardiac conduction abnormalities should be investigated in further studies.

Effects of Dexmedetomidine on Myocardial Repolarization in Children Undergoing General Anesthesia: A Randomized Controlled Trial

BACKGROUND

Dexmedetomidine is a highly selective α2-adrenergic agonist, which is increasingly used in pediatric anesthesia and intensive care. Potential adverse effects that have not been rigorously evaluated in children include its effects on myocardial repolarization, which is important given that the drug is listed as a possible risk factor for torsades de pointes. We investigated the effect of 3 different doses of dexmedetomidine on myocardial repolarization and transmural dispersion in children undergoing elective surgery with total IV anesthesia.

METHODS

Sixty-four American Society of Anesthesiologists I-II children 3-10 years of age were randomized to receive dexmedetomidine 0.25 µg/kg, 0.5 µg/kg, 0.75 µg/kg, or 0 µg/kg (control), as a bolus administered over 60 seconds, after induction of anesthesia. Pre- and postintervention 12-lead electrocardiograms were recorded. The interval between the peak and the end of the electrocardiogram T wave (Tp-e; transmural dispersion) and heart rate-corrected QT intervals (myocardial repolarization) were measured by a pediatric electrophysiologist blinded to group allocation. Data were analyzed using an analysis of covariance regression model. The study was powered to detect a 25-millisecond difference in Tp-e.

RESULTS

Forty-eight children completed the study, with data analyzed from 12 participants per group. There were no instances of dysrhythmias. Tp-e values were unaffected by dexmedetomidine administration at any of the studied doses (F = 0.09; P = .96). Mean (99% CI) within-group differences were all <2 milliseconds (-5 to 8). Postintervention, corrected QT interval increased in the control group, but decreased in some dexmedetomidine groups (F = 7.23; P < .001), specifically the dexmedetomidine 0.5 and 0.75 µg/kg doses. Within groups, the mean (99% CI) differences between pre- and postintervention corrected QT interval were 12.4 milliseconds (-5.8 to 30.6) in the control group, -9.0 milliseconds (-24.9 to 6.9) for dexmedetomidine 0.25 µg/kg, -18.6 milliseconds (-33.7 to -3.5) for dexmedetomidine 0.5 µg/kg, and -14.1 milliseconds (-27.4 to -0.8) for dexmedetomidine 0.75 µg/kg.

CONCLUSIONS

Of the bolus doses of dexmedetomidine studied, none had an effect on Tp-e and the dexmedetomidine 0.5 and 0.75 µg/kg doses shortened corrected QT intervals when measured at 1 minute after dexmedetomidine bolus injection during total IV anesthesia. There is no evidence for an increased risk of torsades de pointes in this context.

Effectiveness of intravenous lidocaine in preventing postoperative nausea and vomiting in pediatric patients: A systematic review and meta-analysis

BACKGROUND

Intravenous lidocaine in adults undergoing general anesthesia has been shown to reduce the incidence of postoperative nausea and vomiting (PONV). However, the anti-postoperative vomiting (POV) effect of lidocaine in pediatric patients remains unclear. We conducted a systematic review and meta-analysis with Trial Sequential Analysis to evaluate the effect of intravenous lidocaine on prevention of POV/PONV.

METHODS

Six databases including trial registration sites were searched. Randomized clinical trials evaluating the incidence of POV/PONV after intravenous lidocaine compared with control were included. The primary outcome was the incidence of POV within 24 hours after general anesthesia. The incidence of POV was combined as a risk ratio with 95% confidence interval using a random-effect model. We used the I2 to assess heterogeneity. We evaluated the quality of trials using the Cochrane methodology, and we assessed quality of evidence using the Grading of Recommendation Assessment, Development, and Evaluation approach. We also assessed adverse events.

RESULTS AND DISCUSSION

Six trials with 849 patients were included, of whom 433 received intravenous lidocaine. Three trials evaluated the incidence of POV, and 3 evaluated the incidence of PONV. The overall incidence of POV within 24 hours after anesthesia was 45.9% in the lidocaine group and 63.4% in the control group (risk ratio, 0.73; 95% confidence interval, 0.53-1.00; I2 = 32%; p = 0.05). The incidence of PONV within 24 hours after anesthesia was 3.73% in the lidocaine group and 4.87% in the control group (RR, 0.76; 95% CI, 0.36-1.59; I2 = 0%; p = 0.47). The quality of evidence was downgraded to "very low" due to the study designs, inconsistency, imprecision, and possible publication bias.

CONCLUSION

Our meta-analysis suggests that intravenous lidocaine infusion may reduce the incidence of POV, however, the evidence quality was "very low." Further trials with a low risk of bias are necessary.

Effect of Intravenous Ondansetron on the QT Interval of Patients' Electrocardiograms

OBJECTIVE

Ondansetron improves the success of oral rehydration in children with gastroenteritis. In postoperative adults, ondansetron has been shown to prolong the corrected QT (QTc). The aim of the study was to evaluate the effect of ondansetron on the QT at peak effect and at 1-hour postpeak effect in pediatric patients.

METHODS

This was an observational study looking at patients aged 6 months to 18 years receiving intravenous ondansetron for nausea, vomiting, or the inability to take fluids in the emergency department. Patients had electrocardiogram performed at baseline, at ondansetron's peak effect, and 1 hour postpeak effect. A paired samples Student t test compared QTc change at peak effect to zero. Peak effect of intravenous ondansetron is 3 minutes.

RESULTS

One hundred patients were included. Fifty-five percent of patients were female with a mean age of 8.3 years. The mean (range) baseline QTc was 435 (388 to 501) milliseconds. The mean (range) change in QTc at peak effect of ondansetron was 3 (-40 to 65) milliseconds (P = 0.072). The change in QTc 1-hour postpeak effect of ondansetron was 3 (-43 to 45) milliseconds (P = 0.082). No change at peak effect or 1-hour postpeak effect was clinically significant.

CONCLUSIONS

Ondansetron does not affect the QTc of pediatric patients receiving the medication for nausea, vomiting, or inability to take fluids in the emergency department. No changes in the QTc are clinically significant. To date, there have been no studies evaluating the effect of ondansetron in this acutely ill population; therefore, a larger study should be completed to confirm these data.

Sevoflurane prolonged the QTc interval and increased transmural dispersion of repolarization in a patient with long QT syndrome 3: a case report

We report that sevoflurane not only caused marked QTc interval prolongation but also increased transmural dispersion of repolarization in a patient with long QT syndrome 3 (LQT3). A 16-year-old male with LQT3 underwent a shoulder operation. He experienced no episode of syncope or cardiac arrest, but his preoperative electrocardiography (ECG) showed marked QTc interval prolongation (631 ms) and Tp-e interval prolongation (126 ms). Anesthesia was induced with propofol and maintained with 2% sevoflurane and remifentanil. Although no lethal arrhythmias occurred in the perioperative period, not only the QTc interval but also Tp-e interval was further prolonged by sevoflurane. While sevoflurane has been recognized as a safe anesthetic in terms of QT interval prolongation, even in patients with long QT syndromes, we believe that sevoflurane might be avoided for poorly controlled LQT3 patients.

Risk of Ventricular Arrhythmias and Association with Ondansetron

OBJECTIVES

To evaluate the use of ondansetron in a tertiary care pediatric health system, assess the incidence of ventricular tachyarrhythmia within 24 hours of ondansetron, and identify the characteristics of children experiencing a ventricular tachyarrhythmia after ondansetron, to identify potential risk factors.

STUDY DESIGN

This retrospective chart review identified children ≤18 years of age who received ondansetron within 24 hours prior to a ventricular tachyarrhythmia. Those identified were evaluated for other diagnoses, concomitant medication use, electrolyte abnormalities, or underlying conduction abnormalities that may have contributed to the arrhythmia.

RESULTS

A total of 199 773 doses of ondansetron were administered to 37 794 patients over 58 009 visits. Average dose was 0.13 mg/kg/dose (range 0.005-0.86 mg/kg/dose). Seven patients received ondansetron within 24 hours prior to a ventricular arrhythmia. All 7 patients had underlying congenital cardiac conduction abnormalities (n = 3) or other major cardiac diagnoses (n = 4). In clinical review, torsades de pointes was found in only 1 of the 7 patients.

CONCLUSIONS

This retrospective study found the risk of ventricular arrhythmia within 24 hours after ondansetron administration was 3 in 100 000 patients treated annually (0.003%). Children with major cardiac conditions could be considered for electrocardiogram screening and continuous cardiac monitoring while receiving ondansetron. Our findings do not support recommendations for electrocardiogram screening or continuous monitoring of other pediatric populations receiving ondansetron.

Fatal Cardiac Arrest in 2 Children: Possible Role of Ondansetron

INTRODUCTION

Ondansetron is commonly used to treat vomiting in gastroenteritis, but has a United States Food and Drug Administration black box warning for risk of Q wave to T wave time interval (QT) prolongation. We report 2 pediatric cases of fatal refractory cardiac arrest after administration of ondansetron.

CASES

A 10-year-old previously healthy boy presented to the emergency room with gastroenteritis symptoms. After intravenous fluids, morphine, antibiotics, and 2 doses of ondansetron, the patient became unresponsive with agonal respirations and a wide complex tachycardia consistent with ventricular tachycardia. In a second case, an 86-day-old infant with previously unidentified congenital cardiomyopathy presented to our emergency department with gastroenteritis symptoms. The patient received ondansetron and subsequently experienced repeated bouts of supraventricular tachycardia which progressed to ventricular fibrillation. Resuscitation efforts failed in each case, and both patients expired.

DISCUSSION

Ondansetron can cause dose-dependent QT prolongation effects, which are more clinically relevant when other proarrhythmic elements are present. There is very limited published experience on use of ondansetron in children younger than 2 years. Our 2 cases join 2 previous case reports of death after ondansetron administration for gastroenteritis. The pharmacology of ondansetron's cardiac effects and drug-induced QT prolongation is discussed.

CONCLUSIONS

Patients may have hidden risk factors that, together with ondansetron, could result in a proarrhythmic state that could lead to adverse effects, such as arrhythmias. Administration of ondansetron should be individualized and used cautiously in patients with risk factors for arrhythmia.

Effect of Ondansetron on QT Interval in Patients Cared for in the PICU

OBJECTIVES

There is no evidence regarding the effect of ondansetron on the QT interval in pediatric patients in the ICU. This study aimed to describe the effect of ondansetron on the corrected QT interval in patients cared for in the PICU.

DESIGN

Retrospective cohort, consecutive enrollment study.

SETTING

Single-center, tertiary-level, medical/surgical PICU.

PATIENTS

All patients less than 8 years old who received ondansetron over an 11-month period were included. Exclusion criteria were atrial arrhythmia, bundle-branch block, known congenital long QT syndrome, and concomitant administration of proarrhythmic antiarrhythmic agents.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Overall, 210 doses of ondansetron were administered to 107 patients, with a mean age 10.5 ± 4.8 years; 49% were men. Corrected QT interval increased to 460-500 ms in 29% and to more than 500 ms in 11% of events of ondansetron administration. The mean baseline corrected QT interval even before ondansetron administration was higher for these groups (460-500 and > 500 ms; 457 ± 33 and 469 ± 45, respectively; p ≤ 0.05). In multivariate analysis, both groups were associated significantly with underlying electrolyte abnormalities (odds ratio, 2.2; 95% CI, 1.1-4.4 and odds ratio, 5.1; 95% CI, 1.8-15.7, respectively); the group with corrected QT interval more than 500 ms was also significantly associated with organ dysfunction (odds ratio, 3.2; 95% CI, 1.1-9.4). As the numbers of risk factors increased from only ondansetron to three additional QT aggravating factors (electrolyte abnormalities, administration of other QT-prolonging drugs, and organ dysfunction), the likelihood of being associated with corrected QT interval more than 500 ms increased.

CONCLUSIONS

Prolonged QT interval is observed commonly in PICUs following the administration of ondansetron. Underlying risk factors, such as electrolyte abnormalities and organ dysfunction, seem to pose the highest risk of prolongation of QT interval in these patients. The awareness of prevalent risk factors for increased corrected QT interval may help identify patients at high risk for arrhythmias.

Small doses of droperidol do not present relevant torsadogenic actions: a double-blind, ondansetron-controlled study

AIM

Drugs used for postoperative nausea and vomiting prophylaxis are believed to provoke torsadogenic changes in cardiac repolarization. The aim of this study was to assess the effect of small doses of droperidol on the parameters of cardiac repolarization, including the QTc interval and transmural dispersion of repolarization.

METHODS

A total of 75 patients were randomly allocated to receive 0.625 or 1.25 mg droperidol or 8 mg ondansetron. The QTc interval was calculated using Bazett's formula and the Framingham correction. The transmural dispersion of repolarization was determined as Tpeak -Tend time.

RESULTS

Transient QT prolongation, corrected with both formulae, followed 1.25 mg of droperidol 10 min after administration. No change in the QTc value was observed in the other groups. When corrected with Bazett's formula, QTc was prolonged above 480 ms in two patients receiving 1.25 mg droperidol (at the 10(th) and 20(th) minute of the study) and in one receiving ondansetron. No patients developed a QTc B prolongation over 500 ms. No increase above 480 ms was observed relative to the Framingham correction method. There were no significant differences in the Tpeak -Tend time either between or within the groups.

CONCLUSION

In men without cardiovascular disorders small doses (1.25 mg) of droperidol prophylaxis induced transient QTc prolongation without changes in transmural dispersion of repolarization. The apparently low risk of the drug applies only in low risk male patients with a low pro-QTc score.

Effects of droperidol and ondansetron on dispersion of ventricular repolarization: A randomized double-blind clinical study in anesthetized adult patients

BACKGROUND AND OBJECTIVE

Droperidol and ondansetron prolong QT interval, a circumstance that has raised some concerns regarding the possibility of inducing torsades de pointes (TdP). However drug-induced spatial dispersion of ventricular repolarization has been shown to be the principal arrhythmogenic substrate for TdP. The aim of this study is to explore the effects of droperidol and ondansetron on the dispersion of repolarization, measured using the T peak-to-end interval (Tp-e) and Tp-e/QT and Tp-e/RR(1/2) ratios in surgical anesthetized patients.

METHODS

A randomized, double-blind study carried out on sixty-three adult patients without cardiac disease or factors favoring QT prolongation and undergoing non-cardiac surgery were randomly assigned to the droperidol or ondansetron group. Under propofol anesthesia, a 12-lead EKG was obtained, and 1.25mg droperidol or 4mg ondansetron was injected. Five minutes later, a new 12-lead EKG was recorded. EKG analyses were independently performed by two cardiologists blinded to the state of the traces or group allocation. QT, RR and Tp-e intervals were measured by averaging five successive beats in leadII (QT) or V5 (Tp-e). The mean value for each measurement was calculated for statistical analysis.

RESULTS

Thirty-two patients (19 women) received droperidol, and 31 (22 women) ondansetron. Droperidol and ondansetron prolonged the QTcF interval (Fridericia formula) by 6.8 and 7.2ms (mean values) respectively, but neither droperidol nor ondansetron increased the Tp-e interval or Tp-e/QT and Tp-e/RR(1/2) ratios.

CONCLUSION

At antiemetic doses, neither ondansetron (4mg) nor droperidol (1.25mg) increases the dispersion of ventricular repolarization in healthy adult patients anesthetized with propofol.

Comparative safety of serotonin (5-HT3) receptor antagonists in patients undergoing surgery: a systematic review and network meta-analysis

BACKGROUND

Serotonin (5-HT3) receptor antagonists are commonly used to decrease nausea and vomiting for surgery patients, but these agents may be harmful. We conducted a systematic review on the comparative safety of 5-HT3 receptor antagonists.

METHODS

Searches were done in MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials to identify studies comparing 5-HT3 receptor antagonists with each other, placebo, and/or other antiemetic agents for patients undergoing surgical procedures. Screening search results, data abstraction, and risk of bias assessment were conducted by two reviewers independently. Random-effects pairwise meta-analysis and network meta-analysis (NMA) were conducted. PROSPERO registry number: CRD42013003564.

RESULTS

Overall, 120 studies and 27,787 patients were included after screening of 7,608 citations and 1,014 full-text articles. Significantly more patients receiving granisetron plus dexamethasone experienced an arrhythmia relative to placebo (odds ratio (OR) 2.96, 95 % confidence interval (CI) 1.11-7.94), ondansetron (OR 3.23, 95 % CI 1.17-8.95), dolasetron (OR 4.37, 95 % CI 1.51-12.62), tropisetron (OR 3.27, 95 % CI 1.02-10.43), and ondansetron plus dexamethasone (OR 5.75, 95 % CI 1.71-19.34) in a NMA including 31 randomized clinical trials (RCTs) and 6,623 patients of all ages. No statistically significant differences in delirium frequency were observed across all treatment comparisons in a NMA including 18 RCTs and 3,652 patients.

CONCLUSION

Granisetron plus dexamethasone increases the risk of arrhythmia.

Postoperative nausea and vomiting in pediatric anesthesia

PURPOSE OF REVIEW

Postoperative nausea and vomiting (PONV) has a high incidence in children and requires prophylactic and therapeutic strategies.

RECENT FINDINGS

PONV can be reduced by the avoidance of nitrous oxide, volatile anesthetics, and the reduction of postoperative opioids. The use of dexamethasone, 5-HT3 antagonists, or droperidol alone is potent, but combinations are even more effective to reduce PONV. Droperidol has a Food and Drug Administration warning. Hence, dexamethasone and 5-HT3 antagonists should be preferred as prophylactic drugs. It is further reasonable to adapt PONV prophylaxis to different risk levels. Prolonged surgery time, inpatients, types of surgery (e.g. strabismus and ear-nose-throat surgery), and patients with PONV in history should be treated as high risk, whereas short procedures and outpatients are to be treated as low risk.

SUMMARY

Concluding from the existing guidelines and data on the handling of PONV in children at least 3 years, the following recommendations are given: outpatients undergoing small procedures should receive a single prophylaxis, outpatients at high risk a double prophylaxis, inpatients with surgery time of more than 30 min and use of postoperative opioids should get double prophylaxis, and inpatients receiving a high-risk surgical procedure or with other risk factors a triple prophylaxis (two drugs and total intravenous anesthesia). Dimenhydrinate can be used as a second choice, whereas droperidol and metoclopramide can only be recommended as rescue therapy.

Effect of ramosetron on the QT interval during sevoflurane anaesthesia in children: a prospective observational study

BACKGROUND

We investigated the effects of concomitant administration of sevoflurane and ramosetron on the QT interval, the interval between the peak and end of the T wave (Tpe) and Tpe/QT ratio in children.

OBJECTIVES

To compare the effects of concomitant administration of ramosetron and sevoflurane on heart rate corrected interval with Bazett's formula (QTc), Tpe interval and Tpe/QT ratio.

DESIGN

A prospective observational study.

SETTING

Elective orthopaedic surgery with patient-controlled analgesia.

PATIENTS

Forty children aged between 3 and 12 years.

INTERVENTION

ECG recordings were collected before induction (BASE), before sevoflurane administration (SEVO) and after the administration of ramosetron (SEVO and R).

MAIN OUTCOME MEASURES

The heart rate corrected interval with Bazett's formula (QTc), Tpe interval and Tpe/QT ratio were calculated and the changes were analysed using repeated-measures analysis of variance (ANOVA).

RESULTS

The QTc interval at BASE was 388.5 ± 29.3 ms. It increased with sevoflurane anaesthesia to 414.9 ± 21.4 ms and did not change with the administration of ramosetron (418.2 ± 23.0 ms). The Tpe interval and Tpe/QT ratio did not differ between measurements. No ventricular arrhythmias occurred during the study.

CONCLUSION

Ramosetron was not associated with prolongation of the QTc interval when it was given concomitantly with sevoflurane in children. No ventricular arrhythmias or other adverse effects occurred during the study.

The safety of modern anesthesia for children with long QT syndrome

BACKGROUND

Patients with long QT syndrome (LQTS) may experience a clinical spectrum of symptoms, ranging from asymptomatic, through presyncope, syncope, and aborted cardiac arrest, to sudden cardiac death. Arrhythmias in LQTS are often precipitated by autonomic changes. This patient population is believed to be at high risk for perioperative arrhythmia, specifically torsades de pointes (TdP), although this perception is largely based on limited literature that predates current anesthetic drugs and standards of perioperative monitoring. We present the largest multicenter review to date of anesthetic management in children with LQTS.

METHODS

We conducted a multicentered retrospective chart review of perioperative management of children with clinically diagnosed LQTS, aged 18 years or younger, who received general anesthesia (GA) between January 2005 and January 2010. Data from 8 institutions were collated in an anonymized database.

RESULTS

One hundred three patients with LQTS underwent a total of 158 episodes of GA. The median (interquartile range) age and weight of the patients at the time of GA was 9 (3-15) years and 30.3 (15.4-54) kg, respectively. Surgery was LQTS-related in 81 (51%) GA episodes (including pacemaker, implantable cardioverter-defibrillator, and loop recorder insertions and revisions and lead extractions) and incidental in 77 (49%). β-blocker therapy was administered to 76% of patients on the day of surgery and 47% received sedative premedication. Nineteen percent of patients received total IV anesthesia, 30% received total inhaled anesthesia, and the remaining 51% received a combination. No patient received droperidol. There were 5 perioperative episodes of TdP, all in neonates or infants, all in surgery that was LQTS-related, and none of which was overtly attributable to anesthetic regimen. Thus the incidence (95% confidence interval) of perioperative TdP in incidental versus LQTS-related surgery was 0/77 (0%; 0%-5%) vs 5/81 (6.2%; 2%-14%).

CONCLUSIONS

With optimized perioperative management, modern anesthesia for incidental surgery in patients with LQTS is safer than anecdotal case report literature might suggest. Our series suggests that the risk of perioperative TdP is concentrated in neonates and infants requiring urgent interventions after failed first-line management of LQTS.

Ventricular tachycardia after ketamine sedation for fracture reduction

This case report describes a 10-year-old female patient who underwent ketamine sedation for fracture reduction and experienced asymptomatic ventricular tachycardia after the sedation. She had no history of syncope, chest pain, palpations, or light-headedness and had a normal physical examination. This is the first reported case of a patient experiencing ventricular tachycardia after ketamine use for sedation. This case demonstrates a serious and potentially harmful possible adverse effect of ketamine administration.

The effect of sevoflurane and ondansetron on QT interval and transmural dispersion of repolarization in children

BACKGROUND

This study evaluated the prolongation of QT interval by the combination of sevoflurane and ondansetron in pediatric patients. Additionally, transmural dispersion of repolarization as interval between the peak and end of the T wave (Tp-e) and Tp-e/QT ratio was also measured to assess the risk of ventricular arrhythmia.

METHODS

The 3-lead electrocardiography (ECG) in lead II was sampled at three stages: at preinduction, just before (Sevo alone) and finally, after administration of ondansetron (Sevo+Ondansetron) in 41 children aged from 3 to 12 years. The QT interval was corrected for heart rate using Bazett's formula. And, Tp-e interval was obtained, and Tp-e/QT ratio was calculated. For analysis of the changes of parameters, a repeated-measures analysis of variance was used to identify significant differences in QTc, Tp-e interval and Tp-e/QT ratio at the three epochs.

RESULTS

The mean QTc at preinduction period was 413.8 (20.8) ms. The mean Sevo alone and Sevo+Ondansetron QTcs were 432.5 (28.1) and 439.2 (27.6) ms, and the differences in QTc prolongation between stages were all significant (P < 0.01). Ondansetron increased Tp-e interval significantly; however, Tp-e/QT ratio was not different among three stages. There were no ECG abnormalities such as atrial or ventricular arrhythmia and T-wave abnormality in any patient.

CONCLUSIONS

Sevoflurane prolongs the QTc interval and its combination with ondansetron further increased this effect in children. However, the dispersion of ventricular repolarization was not significantly affected, and there were no adverse events such as ventricular arrhythmia in this study. The combination of sevoflurane and ondansetron may be clinically safe, but careful ECG monitoring is still advisable.

Consensus guidelines for the management of postoperative nausea and vomiting

The present guidelines are the most recent data on postoperative nausea and vomiting (PONV) and an update on the 2 previous sets of guidelines published in 2003 and 2007. These guidelines were compiled by a multidisciplinary international panel of individuals with interest and expertise in PONV under the auspices of the Society for Ambulatory Anesthesia. The panel members critically and systematically evaluated the current medical literature on PONV to provide an evidence-based reference tool for the management of adults and children who are undergoing surgery and are at increased risk for PONV. These guidelines identify patients at risk for PONV in adults and children; recommend approaches for reducing baseline risks for PONV; identify the most effective antiemetic single therapy and combination therapy regimens for PONV prophylaxis, including nonpharmacologic approaches; recommend strategies for treatment of PONV when it occurs; provide an algorithm for the management of individuals at increased risk for PONV as well as steps to ensure PONV prevention and treatment are implemented in the clinical setting.

Does low-dose droperidol increase the risk of polymorphic ventricular tachycardia or death in the surgical patient?

BACKGROUND

The Food and Drug Administration issued a black box warning regarding the use of droperidol and the potential for torsade de pointes.

METHODS

The primary objective of this retrospective study was to determine if low-dose (0.625 mg) droperidol administration was associated with episodes of torsade de pointes in the general surgical population during the 3-yr period following the reinstitution of droperidol to our institutional formulary.

RESULTS

The authors identified 20,122 surgical patients who received 35,536 doses of droperidol. These patients were cross-matched with an electrocardiogram database and an adverse outcome database. The charts of 858 patients were reviewed, including patients with documentation of prolonged QTc (>440 ms) from March 2007 to February 2011, polymorphic ventricular tachycardia (VT) within 48 h of receiving droperidol, or death within 7 days of receiving droperidol. Twelve surgical patients had VT (n = 4) or death (n = 8) documented within 48 h of droperidol administration. No patients developed polymorphic VT or death due to droperidol administration (n = 0). The eight patients that died were on palliative care. The four patients with documented VT had previous cardiac conditions: two had pre-existing implantable cardiac defibrillators, three had episodes of VT before receiving droperidol, and another had pre-existing hypertrophic obstructive cardiomyopathy. The authors found 523 patients with a documented QTc >440 ms before receiving droperidol. No patients developed VT or death as a direct result of droperidol administration.

CONCLUSIONS

Our evidence suggests that low-dose droperidol does not increase the incidence of polymorphic VT or death when used to treat postoperative nausea and vomiting in the surgical population.

Perioperative torsade de pointes: a systematic review of published case reports

BACKGROUND

Torsade de pointes is a rare but potentially fatal arrhythmia. More than 40 cases of perioperative torsade de pointes have been reported in the literature; however, the current evidence regarding this complication is very limited. To improve our understanding, we performed a systematic review and meta-analysis of all published case reports of perioperative torsade de pointes.

METHODS

MEDLINE was systematically searched for cases of perioperative torsade de pointes. We included patients of all age groups and cases that occurred from the immediate preoperative period to the third postoperative day. Patient and case characteristics as well as QT interval data were extracted.

RESULTS

Forty-six cases of perioperative torsade de pointes were identified; 29 occurred in women (67%), and 2 episodes were fatal (case fatality rate: 4%). Craniotomies and cardiac surgery accounted for 40% of all cases. Preceding events identified by the authors were hypokalemia (12/46, 26%; 99% confidence interval [CI], 9%-43%) and bradycardia (7/46, 15%; 99% CI, 2%-28%). Drugs were implicated in approximately one third of the events (14/46, 30%; 99% CI, 13%-48%). The mean corrected QT (QTc) at baseline was 457 ± 67 milliseconds (minimum 320 milliseconds; maximum 647 milliseconds; data available in 27/46 patients). At the time of the event, the mean QTc increased to 575 ± 77 milliseconds (minimum 413 milliseconds; maximum 766 milliseconds; data available in 33/46 patients). On average, QTc increased by +118 milliseconds (99% CI, 70-166 milliseconds; P < 0.001) between baseline and after the torsade de pointes event. All patients, except for 2, had a substantial prolongation of their QTc interval at the time of the event.

CONCLUSIONS

This systematic review identified several common risk factors for perioperative torsade de pointes. Given the nearly uniform presence of a substantial QTc interval prolongation at the time of a torsade de pointes episode, increased vigilance for perioperative QTc interval prolongation may be warranted.

[Low-dose droperidol in children: rescue therapy for persistent postoperative nausea and vomiting]

BACKGROUND

Droperidol had been used as an effective antiemetic since the 1970s but was withdrawn from the market in 2001 because of a black box warning about QT prolongation and possible cardiac arrhythmia after high doses. In the meantime the black box warning has seriously been questioned and parenteral droperidol has again been licensed in 2008. Because droperidol acts on dopaminergic receptors different to 5-HT(3) antagonists and dexamethasone, it could possibly serve as a rescue drug after failed postoperative nausea and vomiting (PONV) prophylaxis. Persistent PONV after the recommended prophylaxis is a significant problem in pediatric anesthesia but a satisfactory strategy has not yet been defined. Therefore a retrospective audit was performed in order to evaluate whether low-dose droperidol (10 µg/kgBW) would be an effective rescue drug for failed antiemetic prophylaxis.

PATIENTS AND METHODS

The electronic anesthesia patient data base of the University Children's Hospital Zurich was searched from 2004-2009 for patients who received low-dose droperidol in the postanesthesia care unit as rescue therapy for persistent PONV after antiemetic prophylaxis. Based on the recorded electronic data the effectiveness of low-dose droperidol as PONV rescue therapy and possible side effects were analyzed.

RESULTS

A total of 338 patients who received droperidol were found from a total of 34,032 patients and the charts were analyzed. Of these patients 134 were excluded because they had received droperidol for indications other than PONV, 43 patients were excluded because they had not received antiemetic prophylaxis before droperidol and in 17 patients the data were incomplete, leaving 144 patients with an average age of 12.3 years (interquartile range IQR 9.5-15.2 years) for analysis. The upper range of ages resulted from patients with chronic diseases who were still being treated in the Children's Hospital. Low-dose droperidol was given because of persistent nausea to 59 patients (41%) and to 85 patients (59%) for persistent vomiting. Initial antiemetic prophylaxis and/or therapy had consisted of dexamethasone plus tropisetrone in 80 patients and tropisetrone or dexamethasone alone in 64 patients. In 128 patients (89%) rescue therapy with a median dose of 10.9 µg/kgBW droperidol was effective but vomiting persisted in 16 patients (11%). Sedation was the only side effect recorded and this was observed in 39 patients (27%).

CONCLUSIONS

Low-dose droperidol (10 µg/kgBW) was found to be effective as rescue medication in pediatric patients experiencing PONV despite various prophylactic antiemetic regimens. No neurological or cardiopulmonary side effects were recorded after this low dosage.