Effect of low-dose droperidol on the QT interval during and after general anesthesia: a placebo-controlled study

BACKGROUND: Since the effects of antiemetic doses of droperidol on the QT interval have not been previously studied, the authors designed a randomized, double-blind, placebo-controlled study to evaluate the intraoperative and postoperative effects of small-dose droperidol (0.625 and 1.25 mg intravenous) on the QT interval when used for antiemetic prophylaxis during general anesthesia. METHODS: One hundred twenty outpatients undergoing otolaryngologic procedures with a standardized general anesthetic technique were enrolled in this study. After anesthetic induction and before the surgical incision, 60 patients were given either saline or 0.625 or 1.25 mg intravenous droperidol in a total volume of 2 ml. A standard electrocardiographic lead II was recorded immediately before and every minute after the injection of the study medication during a 10-min observation period. The QTc (QT interval corrected for heart rate) was evaluated from the recorded electrocardiographic strips. In 60 additional patients, a 12-lead electrocardiogram was obtained before and at specific intervals up to 2 h after surgery to assess the effects of droperidol and general anesthesia on the QTc. Any abnormal heartbeats or arrhythmias during the operation or the subsequent 2-h monitoring interval were also noted. RESULTS: Intravenous droperidol, 0.625 and 1.25 mg, prolonged the QT interval by an average of 15 +/- 40 and 22 +/- 41 ms, respectively, at 3-6 min after administration during general anesthesia, but these changes did not differ significantly from that seen with saline (12 +/- 35 ms) (all values mean +/- SD). There were no statistically significant differences among the three study groups in the number of patients with greater than 10% prolongation in QTc (vs. baseline). Although general anesthesia was associated with a 14- to 16-ms prolongation of the QTc interval in the early postoperative period, there was no evidence of droperidol-induced QTc prolongation after surgery. Finally, there were no ectopic heartbeats observed on any of the electrocardiographic rhythm strips or 12-lead recordings during the perioperative period. CONCLUSION: Use of a small dose of droperidol (0.625-1.25 mg intravenous) for antiemetic prophylaxis during general anesthesia was not associated with a statistically significant increase in the QTc interval compared with saline. More importantly, there was no evidence of any droperidol-induced QTc prolongation immediately after surgery.     

Prolongation of QTc interval after postoperative nausea and vomiting treatment by droperidol or ondansetron

BACKGROUND: At dosages above 0.1 mg/kg, droperidol induces a dose-dependent QTc interval prolongation. Although subject to controversy, low-dose droperidol has recently been suspected to induce cardiac arrhythmias. Hence, 5-hydroxytryptamine type 3 antagonists have become the first-line drug for management of postoperative nausea and vomiting. These drugs are also known to prolong the QTc interval at high dosages. This study describes QTc interval changes associated with postoperative nausea and vomiting treatment by droperidol or ondansetron at low doses. METHODS: Eighty-five patients with postoperative nausea and vomiting were included in this prospective, single-blind study. Patients received either 0.75 mg intravenous droperidol (n = 43) or 4 mg intravenous ondansetron (n = 42). Electrocardiographic recordings were obtained before administration of antiemetic drug and then 1, 2, 3, 5, 10, and 15 min after. Electrocardiographic monitoring was maintained for 3 h in eight patients in each group. RESULTS: The QTc interval was prolonged (> 450 ms in men, > 470 ms in women) in 21% of the patients before antiemetic drug administration. This was significantly correlated with lower body temperature and longer duration of anesthesia. Compared with predrug QTc measurement, both antiemetics were associated with a significant QTc interval prolongation (P < 0.0001). The mean maximal QTc interval prolongation was 17 +/- 9 ms after droperidol occurring at the second minute and 20 +/- 13 ms after ondansetron at the third minute (both P < 0.0001). Compared with predrug measurement, the QTc interval was significantly lower after the 90th minute in both groups. CONCLUSIONS: Droperidol and ondansetron induced similar clinically relevant QTc interval prolongations. When used in treatment of postoperative nausea and vomiting, a situation where prolongation of the QTc interval seems to occur, the safety of 5-hydroxytryptamine type 3 antagonists may not be superior to that of low-dose droperidol.     

Effect of Low-dose Droperidol on the QT Interval during and after General Anesthesia: A Placebo-controlled Study

Background: Since the effects of antiemetic doses of droperidol on the QT interval have not been previously studied, the authors designed a randomized, double-blind, placebo-controlled study to evaluate the intraoperative and postoperative effects of small-dose droperidol (0.625 and 1.25 mg intravenous) on the QT interval when used for antiemetic prophylaxis during general anesthesia.

Methods: One hundred twenty outpatients undergoing otolaryngologic procedures with a standardized general anesthetic technique were enrolled in this study. After anesthetic induction and before the surgical incision, 60 patients were given either saline or 0.625 or 1.25 mg intravenous droperidol in a total volume of 2 ml. A standard electrocardiographic lead II was recorded immediately before and every minute after the injection of the study medication during a 10-min observation period. The QTc (QT interval corrected for heart rate) was evaluated from the recorded electrocardiographic strips. In 60 additional patients, a 12-lead electrocardiogram was obtained before and at specific intervals up to 2 h after surgery to assess the effects of droperidol and general anesthesia on the QTc. Any abnormal heartbeats or arrhythmias during the operation or the subsequent 2-h monitoring interval were also noted.

Results: Intravenous droperidol, 0.625 and 1.25 mg, prolonged the QT interval by an average of 15 +/- 40 and 22 +/- 41 ms, respectively, at 3-6 min after administration during general anesthesia, but these changes did not differ significantly from that seen with saline (12 +/- 35 ms) (all values mean +/- SD). There were no statistically significant differences among the three study groups in the number of patients with greater than 10% prolongation in QTc (vs. baseline). Although general anesthesia was associated with a 14- to 16-ms prolongation of the QTc interval in the early postoperative period, there was no evidence of droperidol-induced QTc prolongation after surgery. Finally, there were no ectopic heartbeats observed on any of the electrocardiographic rhythm strips or 12-lead recordings during the perioperative period.     

Prolongation of QTc Interval after Postoperative Nausea and Vomiting Treatment by Droperidol or Ondansetron

Background: At dosages above 0.1 mg/kg, droperidol inducesa dose-dependent QTc interval prolongation. Although subject to controversy, low-dose droperidol has recently been suspected to induce cardiac arrhythmias. Hence, 5-hydroxytryptamine type 3 antagonists have become the first-line drug for management of postoperative nausea and vomiting. These drugs are also known to prolong the QTc interval at high dosages. This study describes QTc interval changes associated with postoperative nausea and vomiting treatment by droperidol or ondansetron at low doses.

Methods: Eighty-five patients with postoperative nausea and vomiting were included in this prospective, single-blind study. Patients received either 0.75 mg intravenous droperidol (n = 43) or 4 mg intravenous ondansetron (n = 42). Electrocardiographic recordings were obtained before administration of antiemetic drug and then 1, 2, 3, 5, 10, and 15 min after. Electrocardiographic monitoring was maintained for 3 h in eight patients in each group.

Results: The QTc interval was prolonged (> 450 ms in men, > 470 ms in women) in 21% of the patients before antiemetic drug administration. This was significantly correlated with lower body temperature and longer duration of anesthesia. Compared with predrug QTc measurement, both antiemetics were associated with a significant QTc interval prolongation (P < 0.0001). The mean maximal QTc interval prolongation was 17 +/- 9 ms after droperidol occurring at the second minute and 20 +/- 13 ms after ondansetron at the third minute (both P < 0.0001). Compared with predrug measurement, the QTc interval was significantly lower after the 90th minute in both groups.     

The interaction of antiemetic dose of droperidol with propofol on QT interval during anesthetic induction

Purpose

We investigated the effect of low-dose droperidol on heart rate-corrected QT (QTc) interval and interaction with propofol.

Methods

Seventy-two patients undergoing upper limb surgery were included in this study. Patients were randomly allocated to one of three groups: group S (n = 24), which received 1 ml saline; group D1 (n = 24), which received 1.25 mg droperidol; or group D2 (n = 24), which received 2.5 mg droperidol. One minute later, fentanyl (3 μg/kg) was administered. Two minutes after fentanyl administration, anesthesia was induced using propofol (1.5 mg/kg) and vecronium. Tracheal intubation was performed 3 min after the administration of propofol. Heart rate, mean arterial pressure, bispectral index, and QTc interval were recorded at the following time points: immediately before the droperidol injection (baseline); 3 min after the saline or droperidol injection; 3 min after the propofol injection; and 2 min after tracheal intubation.

Results

Compared to baseline, the QTc interval in group S and group D1 was significantly shorter after propofol injection, but recovered after tracheal intubation. In group D2, the QTc interval was significantly prolonged after droperidol injection, but recovered after propofol injection, and was significantly prolonged after tracheal intubation.

Conclusions

We found that saline or 1.25 mg droperidol did not prolong QTc interval, whereas 2.5 mg droperidol prolonged the QTc interval significantly, and that propofol injection counteracted the prolongation of the QTc interval induced by 2.5 mg droperidol.     

七氟烷对QT间期延长的影响在老年人中更明显

背景七氟炕和氟哌利多能延长QT间期。高龄不仅与QT问期延长有关,它也是一种}j起药物诱导的QT间期延长的危险因素。本研究中,我们比较了七氟炕和氧哌利多对于矫正的QT（QYc）间期和心室复极化的传播（T波波峰至T波结束的时间间隔[Tp-e]）在老年患者和年轻患者中的差别。方法在七氟烷（1．5％-2．5％）麻醉和给予止吐剂量的氟哌利多（1．25rag）的30例老年患者（≥70岁）和30例年轻患者（20—69岁）中,测量2小时QT间期和代表心肌壁复极化传播的Tp—e间期。通过3种不同的公式使心率的QT间期标准化：Bazen公式、Matsunaga公式和Vandewa船公式。数据以均数±标准差表示。结果老年组的平均年龄比年轻组大24．4岁（P〈0．05）。两组的QTc间期在麻醉前没有明显的差异。通过3种公式计算发现七氟烷明显延长老年组患者的QTc间期（用Bazecc公式得出在麻醉前、使用七氟烷60分钟、75分钟、90分钟和120分钟时的QTc间期分别是0．434±0．028秒、0．450±0．037秒、0．463±0．037秒、0．461±0．037秒和0．461±O．038秒）。在老年组患者中七氟炕引起QTc间期延长的程度明显高于年轻组（用Bazecc公式计算吸入七氟烷60分钟时：0．450±0．037秒VS0．432±0．034秒;75分钟时：0．463±0．037秒vs0．441±0．037秒;120分钟时：0．461±0．038秒vs0．436±0．030秒）。但是七氟炕引起的QTc间期的延长既不随着时间的延长而延长也不被氟哌利多加重。两组中的Tp—e间期都没有受到影响。结论与年轻组相比,七氟烷引起老年组患者QTc间期的延长更加明显。尽管七氟烷不影响复极化的透壁传播,其引起的QTc闻期延长也不随着时间和给予氧哌利多而加重,但是老年患者在使用七氖烷麻醉期间仍要严密监测QT间期及其相关的心律失常。     

The additive interactions between ondansetron and droperidol for preventing postoperative nausea and vomiting

Prophylactic ondansetron or droperidol reduces the incidence of postoperative nausea and vomiting (PONV). Previous studies showed that the combination of these two drugs produced better antiemetic effect than either drug alone. We present a nonparametric method to determine the pharmacologic interaction between ondansetron and droperidol and compared the observed response of the drug combination with that predicted from additivity. This is calculated as the product of the individual drug response, normalized to that of the controls. Five minutes before induction of anesthesia, 400 patients scheduled for laparoscopic gynecologic surgery were randomly assigned to receive 1) saline IV; 2) ondansetron 4 mg IV; 3) droperidol 1.25 mg IV; or 4) a combination of droperiodol 1.25 mg and ondansetron 4 mg IV. A standardized anesthetic technique and postoperative analgesic regimen were used. Patients were reviewed regularly for 48 h. Changes in the heart rate adjusted QT (QTc) interval were measured from electrocardiograms recorded before and 5 min after study drug administration. In a subgroup of 160 patients, QTc intervals were measured again at 2-3 h after surgery. During the first 48 h after the surgery, the proportion of patients experiencing PONV was 68% (95% CI 58-77) in the control group. A single dose of ondansetron or droperidol decreased the incidence of PONV to 30% (95% CI 21-40) and 28% (95% CI 20-38), respectively. The predicted incidence of PONV after drug combination, 11.8% (7.1-11.9), was similar to that observed, 12.1% (6.4-20.2), P = 0.94. The corresponding predicted and observed treatment responses in the combination group were 88.2% and 87.9%, respectively. There was a modest and transient increase in QTc interval after administration of ondansetron, droperidol, or their combination. The changes were however similar among groups. We conclude that the interaction between ondansetron and droperiodol was additive. Both drugs acted independently of each other through their specific mechanisms of action. The incidence of QTc prolongation did not increase with the drug combination.     

Influence of spinal anesthesia on corrected QT interval

BACKGROUND AND OBJECTIVES: Prolongation of the QT interval may result in grave cardiac arrhythmias, polymorphic ventricular tachycardia ("torsades de pointes"), and ventricular fibrillation. We assessed the influence of spinal anesthesia on the QTc interval and the potential arrhythmogenicity of this method of anesthesia. METHODS: Assessment was performed in 20 male unpremedicated patients, I or II American Society of Anesthesiologists physical status, who underwent spinal anesthesia for elective surgical procedures. Values of the QTc interval, heart rate, and arterial pressure were measured before spinal anesthesia as well as after 1, 3, 5, and 15 minutes of adequate blockade. RESULTS: Statistically significant lengthening of the QTc interval (compared with initial values) was observed in the first minute after blockade and in subsequent measurements. No differences were observed between mean values of the QTc interval after the onset of blockade. No significant changes in heart rate were noted. From the third minute on, significant decreases of the systolic, diastolic, and mean arterial blood pressure were observed as compared with baseline. These decreases in systolic, diastolic, and mean arterial blood pressure persisted for the entire study duration. No one patient developed clinically important cardiac arrhythmias. CONCLUSIONS: Spinal anesthesia provokes significant QTc interval prolongation in patients without cardiovascular disorders.     

Sustained prolongation of the QTc interval after anesthesia with sevoflurane in infants during the first 6 months of life

BACKGROUND: Sevoflurane, an inhalational anesthetic frequently administered to infants, prolongs the QT interval of the electrocardiogram in adults. A long QT interval resulting in fatal arrhythmia may also be responsible for some cases of sudden death in infants. As the QT interval increases during the second month of life and returns to the values recorded at birth by the sixth month, we evaluated the effect of sevoflurane on the QT interval during and after anesthesia in this particular population. METHODS: In this prospective two-group trial we examined pre-, peri-, and postoperative electrocardiograms of 36 infants aged 1 to 6 months scheduled for elective inguinal or umbilical hernia repair. Anesthesia was induced and maintained with either sevoflurane, or the well-established pediatric anesthetic halothane. Heart rate corrected (c) QTc and JTc interval (indicator of intraventricular conduction delays) were recorded from electrocardiograms before and during anesthesia, and at 60 min after emergence from anesthesia. RESULTS: Prolonged QTc was observed during sevoflurane anesthesia (mean [+/-SD], 473 +/- 19 ms, P< 0.01). Sixty minutes after emergence from anesthesia, QTc was still prolonged (433 +/- 15 ms) in infants treated with sevoflurane compared with those treated with halothane (407 +/- 33 ms, P< 0.01). Analogous differences were found for the JTc interval. CONCLUSIONS: Despite a shorter elimination time than better known inhalational anesthetics, sevoflurane induction and anesthesia results in sustained prolongations of QTc and JTc interval in infants in the first 6 months of life. Electrocardiogram monitoring until the QTc interval has returned to preanesthetic values may increase safety after sevoflurane anesthesia.     

Effects of landiolol on QT interval and QT dispersion during induction of anesthesia using computerized measurement

Study ObjectiveTo examine the effects of landiolol on the QT interval, rate-corrected QT (QTc) interval, QT dispersion (QTD), and rate-corrected QTD (QTcD) during tracheal intubation using computerized measurement.DesignRandomized, double-blinded study.SettingDokkyo Medical University Hospital operating room.Patients30 ASA physical status I patients scheduled for elective surgery.InventionsPatients were randomized to receive either normal saline (saline group) or landiolol (landiolol group; one-min loading infusion of 0.125 mg/kg followed by 0.04 mg/kg/min infusion). Immediately after the start of administration of saline or landiolol, anesthesia was induced with intravenous (IV) fentanyl two μg/kg, propofol 1.5 mg/kg, and vecuronium 0.1 mg/kg. Six minutes after administration of saline or landiolol, tracheal intubation was performed within 20 seconds.MeasurementsMean arterial pressure (MAP), RR interval, QT interval, QTc interval, QTD, and QTcD were consecutively recorded during the induction.Main ResultsThere was no significant difference in MAP between groups during the study. RR interval in the landiolol group was significantly longer than in the saline group from two minutes after the start of the landiolol infusion to the end of the study. The QT interval in the landiolol group was significantly shorter than in the saline group from start of the infusion to 4 minutes after tracheal intubation. The QTc interval, QTD, and QTcD in the landiolol group were significantly shorter than those in the saline group from immediately after tracheal intubation to the end of study.ConclusionA bolus of landiolol 0.125 mg/kg followed by an infusion of landiolol 0.04 mg/kg/min may reduce the risk of cardiac arrhythmias during induction of anesthesia.     

Haloperidol is as effective as ondansetron for preventing postoperative nausea and vomiting

PURPOSE: Recent warnings regarding the safety of droperidol have limited use of this drug as an antiemetic. Haloperidol, a butyrophenone derivative similar to droperidol, has not been rigorously evaluated as an antiemetic. The aim of this study was to compare the prophylactic antiemetic efficacy of haloperidol vs ondansetron for the prevention of postoperative nausea and vomiting (PONV) after general anesthesia. METHODS: Ninety non-smoking female patients were eligible to participate in this randomized double-blinded study. Approximately 30 min before the end of surgery, patients were randomly assigned to receive either haloperidol 2 mg iv, or ondansetron 4 mg iv, respectively. The incidence of PONV, average pain and sedation scores, recovery times, and changes of the rate-corrected QT (QTc) interval were observed postoperatively. RESULTS: The proportion of patients who experienced PONV in the first 24 hr was similar in the two groups (28% and 26% for haloperidol and ondansetron groups, respectively). The incidence of PONV was significantly less in both groups than predicted according to the patients' underlying risks (53% for the haloperidol group, P=0.016; 51% for the ondansetron group, P=0.015). Pain scores, sedation scores, and recovery times were similar in the two groups, and no prolongation of the QTc interval was observed in either group. CONCLUSIONS: Haloperidol 2 mg iv given 30 min before the end of surgery is effective in preventing PONV, with efficacy comparable to ondansetron 4 mg iv for the first 24 hr after general anesthesia.     

氟哌利多、阿扎司琼和格拉司琼对患者校正QT间期影响的比较

目的比较氟哌利多、阿扎司琼、格拉司琼对患者校正QT(QTc)间期的影响。方法择期手术患者80例,随机均分为四组,于麻醉前30min分别静注氟哌利多2.5mg(A组)、阿扎司琼10mg(B组)、格拉司琼3mg(C组)和生理盐水5ml(D组)。记录用药前后ECG,分析QTc间期的变化。结果与用药前比较,A组患者用药后5、10minQTc间期明显延长(P<0.05),且明显长于D组(P<0.05)。其它三组用药后QTc间期无显著变化。结论预防性应用止吐剂量的氟哌利多可引起QTc间期显著延长。     

Intravenous droperidol causes a reduction in the bispectral index in propofol-sedated patients during spinal anesthesia

We investigated the effect of IV droperidol on the bispectral index (BIS) in conscious and propofol-sedated patients during spinal anesthesia. Thirty minutes after the induction of spinal anesthesia, 20 patients were given 2 mg of droperidol IV without administration of other sedatives (conscious group). Another group of patients were sedated with a propofol infusion to maintain BIS at 60 +/- 5 and were administered IV saline (placebo group; n = 20), droperidol 1 mg (dro-1 group; n = 20), or droperidol 2 mg (dro-2 group; n = 20) in a randomized order and in a double-blinded fashion. Although BIS remained the same in the conscious and placebo groups, it significantly decreased after administration of droperidol in the dro-1 and dro-2 groups. The decrease in BIS was significantly larger in the dro-2 group than in the dro-1 group. These results suggest that an antiemetic dose of droperidol enhances the hypnotic effect of propofol in a dose-dependent manner during spinal anesthesia. IMPLICATIONS: An antiemetic dose of IV droperidol causes a decrease in the bispectral index in patients sedated with propofol during spinal anesthesia. We conclude that droperidol may enhance the hypnotic effect of propofol.     

Ondansetron in the treatment of postoperative vomiting: a randomized, double-blind comparison with droperidol and metoclopramide.

The prophylactic antiemetic efficacy of ondansetron was evaluated in a randomized, double-blind comparison with droperidol and metoclopramide in 66 patients undergoing general anesthesia for dilatation and curettage. Ten minutes before induction of anesthesia, 22 patients received a single intravenous dose of 8 mg of ondansetron, 22 others received 1.25 mg of droperidol, and the remaining 22 received 10 mg of metoclopramide. Anesthesia was induced with 3.3-5 mg/kg of intravenous thiopental and maintained with 65% nitrous oxide in oxygen and 2%-3% enflurane. Postoperatively, the incidence of vomiting was 13% with ondansetron, 45% with droperidol, and 54% with metoclopramide (P less than 0.05; overall chi 2 test). There was no statistically significant difference in the incidence of nausea among the groups. Postoperative sedation and well-being scores were not significantly different among the groups. We conclude that preoperative prophylactic administration of ondansetron is superior to droperidol or metoclopramide in the prevention of emetic sequelae after general anesthesia for dilatation and curettage.     

Sustained Prolongation of the QTc Interval after Anesthesia with Sevoflurane in Infants during the First 6 Months of Life

Background: Sevoflurane, an inhalational anesthetic frequently administered to infants, prolongs the QT interval of the electrocardiogram in adults. A long QT interval resulting in fatal arrhythmia may also be responsible for some cases of sudden death in infants. As the QT interval increases during the second month of life and returns to the values recorded at birth by the sixth month, we evaluated the effect of sevoflurane on the QT interval during and after anesthesia in this particular population.

Methods: In this prospective two-group trial we examined pre-, peri-, and postoperative electrocardiograms of 36 infants aged 1 to 6 months scheduled for elective inguinal or umbilical hernia repair. Anesthesia was induced and maintained with either sevoflurane, or the well-established pediatric anesthetic halothane. Heart rate corrected (c) QTc and JTc interval (indicator of intraventricular conduction delays) were recorded from electrocardiograms before and during anesthesia, and at 60 min after emergence from anesthesia.

Results: Prolonged QTc was observed during sevoflurane anesthesia (mean [+/-SD], 473 +/- 19 ms, P < 0.01). Sixty minutes after emergence from anesthesia, QTc was still prolonged (433 +/- 15 ms) in infants treated with sevoflurane compared with those treated with halothane (407 +/- 33 ms, P < 0.01). Analogous differences were found for the JTc interval.     

The effects of sevoflurane and desflurane anesthesia on QTc interval and cardiac rhythm in children

BACKGROUND: Inhalational anesthetics may prolong QTc interval (QT interval corrected for heart rate) of the ECG and cause life-threatening arrythmias. The effects of desflurane on QTc interval and cardiac rhythm have not been reported previously in children. We assessed the effects of desflurane anesthesia on QTc interval and cardiac rhythm and compared them with sevoflurane anesthesia in children. METHODS: The study was performed on 20 children admitted for inguinal hernia repair, with normal QTc intervals. Anesthesia was induced with propofol and intubation was achieved with vecuronium. Anesthesia was maintained with 2% sevoflurane (group I, n = 11) or 6% desflurane (group II, n = 9) and 66% nitrous oxide in oxygen. Electrocardiogram recordings were obtained by Holter recorder. QTc intervals were measured at baseline, 5, 10, 15, and 30 min after inhalation. RESULTS: None of the patients had significant arrythmia with desflurane anesthesia. One patient in the sevoflurane group had single, bigemini and multiform ventricular extrasystoles. There was no statistically significant difference in the baseline QTc values of the groups. Desflurane significantly prolonged QTc interval 5 min after induction until 30 min of anesthesia compared with baseline values (P = 0.029), while no significant prolongation was observed with sevoflurane (P = 0.141). CONCLUSIONS: Use of 2% sevoflurane during maintenance of anesthesia does not significantly prolong QTc interval while 6% desflurane significantly prolonged QTc interval in children with normal QTc interval undergoing inguinal herniorrhaphy.     

A comparison of three drugs (pethidine, magnesium sulfate and droperidol) in patients with post-anesthesia shivering]

Shivering is one of the common complications after general anesthesia. It increases metabolic rate markedly and may cause myocardial ischemia in patients with decreased cardiopulmonary function. We investigated, therefore, the effects of three drugs (pethidine, magnesium sulfate and droperidol) on shivering in 30 patients under enflurane anesthesia. The patients were of ASA class I or II physical status and had no cardiovascular or respiratory disease. For post-anesthesia shivering, every patient was administered with pethidine 0.5 mg.kg-1, MgSO4 30 mg.kg-1 or droperidol 0.15 mg.kg-1. Their VO2 and VCO2 were measured for 5 minutes during shivering and 15 minutes after drug administration. We also evaluated the therapeutic efficacy of each drug for the treatment of shivering by examining VO2 and VCO2 before and after drug administration. With pethidine and MgSO4, both VO2 and VCO2 decreased significantly after each drug administration. With pethidine, VO2 and VCO2 decreased significantly more than that in MgSO4 (P less than 0.01 vs P less than 0.05). But with droperidol, there was no significant change. These results suggest that pethidine is most effective followed by MgSO4.     

Impact of haemodialysis on QTc dispersion in children

BACKGROUND: The purpose of the present paper was to investigate the corrected QT (QTc) interval and QTc dispersion value, and the impact of haemodialysis on these parameters in children with chronic renal failure. METHODS: Nineteen patients with chronic renal failure receiving haemodialysis were included in the present study. Electrocardiography (ECG), echocardiography and serum biochemistry were performed in all patients. Serum electrolyte levels were measured before and after haemodialysis, at the time of the ECG. Nineteen healthy age- and sex-matched children served as the control group. RESULTS: Patients with chronic renal failure had greater QTc interval and QTc dispersion compared to control subjects. The patients' sex, age and presence of hypertension or left ventricular hypertrophy (LVH) were not related to QTc interval/dispersion. However, the patients with left ventricular (LV) systolic dysfunction had significantly greater QTc dispersion value. After haemodialysis session, both QTc interval and QTc dispersion values significantly increased. Serum potassium levels significantly decreased, whereas the calcium level significantly increased after the haemodialysis session. The changes in electrolyte values were not associated with the changes in both QTc interval and QTc dispersion. CONCLUSION: Children receiving haemodialysis may be at greater risk of ventricular arrhythmia and sudden death because QTc dispersion reflects heterogeneous recovery of ventricular excitability.     

Droperidol for perioperative sedation causes a transient prolongation of the QTc time in children under volatile anesthesia

BACKGROUND: Droperidol is useful for postoperative sedation in infants and children after cardiac surgery because it provides sedation and akinesia with minimal respiratory depression. However, droperidol has been associated with QT prolongation and ventricular arrhythmias. We investigated, if neuroleptanalgesic doses of droperidol led to QT prolongation and cardiac arrhythmias in children undergoing cardiac surgery. METHODS: We retrospectively analysed electrocardiogram rhythm strips that were obtained before and in time increments after a 100 microg x kg(-1) intravenous bolus of droperidol in 20 children undergoing cardiac surgery. The longest QT interval was determined in each ECG and corrected for heart rate (QTc). All arrhythmias were recorded. RESULTS: Droperidol led to a significant increase in QTc time that was still present at 15 min but had resolved within 30 min after the bolus. No associated arrhythmias were observed. CONCLUSIONS: The statistically significant prolongation of QTc time after a sedative dose of droperidol is of concern because it may increase the risk for malignant cardiac arrhythmias. A large, prospective study is necessary to identify the true risk for arrhythmias after droperidol in this patient population, but our study suggests that any arrhythmogenic risk, if present, will be very transient, since the increase in QTc time was limited to a period of less than 30 min after the bolus.     

Effects of prophylactic ramosetron and ondansetron on corrected QT interval during general anesthesia

Study ObjectiveTo evaluate whether ramosetron increases the corrected QT (QTc) interval.DesignProspective, randomized, controlled study.SettingOperating room.Patients135 patients undergoing elective laparoscopic cholecystectomy.InterventionPatients were allocated to three groups to receive ondansetron 4 mg (Group O4), ramosetron 0.3 mg (Group R), or ondansetron 8 mg (Group O8). The study drugs were administered intravenously approximately 15 minutes before the end of surgery.MeasurementThe QT interval for 10 minutes after administration was recorded. The QTc interval was calculated according to the Fridericia (QTcF) formula. The primary outcome was the QTcF interval among the three groups during the 10 minutes after administration of the study drugs.Main ResultsThe QTcF interval was not significantly prolonged after administration of ondansetron 4 mg and ramosetron. It was significantly increased from one minute after administration until 7 minutes after ondansetron 8 mg (Group O8). The QTcF interval was significantly longer in Group O8 at 1, 2, 3, 4, and 5 minutes.ConclusionsThe prophylactic administration 0.3 mg of ramosetron does not increase the QTc interval. Ondansetron 8 mg increases the QTc interval more so than 4 mg of ondansetron.