The effect of intravenous lidocaine on QT changes during tracheal intubation

Investigation of proarrhythmic effect of high sugammadex doses: an experimental animal study

BACKGROUND

Studies on higher doses of sugammadex effect on QT interval and leading arrhythmia have been limited. In this study, we aimed to investigate possible proarrhythmic effect of higher doses of sugammadex in conditions that required urgent reversal of neuromuscular blockade during general anesthesia in an experimental animal model.

METHODS

It was experimental animal study. Total of 15 male New Zealand rabbits were randomly divided into three groups for low (4 mg/kg, n = 5), moderate (16 mg/kg, n = 5), and high dose of sugammadex (32 mg/kg, n = 5). All rabbits were premedicated by intramuscular ketamine 10 mg/kg, and general anesthesia was inducted by intravenous injection of 2 mg/kg of a propofol, 1 mcg/kg fentanyl, and 0.6 mg/kg rocuronium injection. Airway was provided by V-gel rabbit and connected to anesthetic device and ventilated at about 40 cycle/min and 10 ml/kg; oxygen 50% plus air 50% mixture was used with 1 MAC isoflurane to maintain anesthesia. Electrocardiographic monitorization and arterial cannulation were provided to follow-up mean arterial pressure and for arterial blood gas analyses. Intravenous sugammadex in three different doses were injected at 25th min of induction. After observing adequate respiration of all rabbits, V-gel rabbit was removed. Parameters and ECG recordings were taken basal value before induction and at the 5th, 10th, 20th, 25th, 30th, and 40th min to measure corrected QT intervals and were stored on digital media. QT interval was calculated as the time from the beginning of the Q wave to the end of the T wave. Corrected QT interval was calculated according to the Bazett's formula. Possible adverse effects were observed and recorded.

RESULTS

In all three groups, there was no significant statistical difference in mean arterial blood gases parameters, arterial pressures, heart rates, and Bazett QTc values, and no serious arrhythmia was recorded.

CONCLUSION

We found in animal study that low, moderate, and high doses of sugammadex did not significantly altered corrected QT intervals and did not cause any significant arrhythmia.

In Vitro Drug Screening Using iPSC-Derived Cardiomyocytes of a Long QT-Syndrome Patient Carrying KCNQ1 & TRPM4 Dual Mutation: An Experimental Personalized Treatment

Congenital long QT syndrome is a type of inherited cardiovascular disorder characterized by prolonged QT interval. Patient often suffer from syncopal episodes, electrocardiographic abnormalities and life-threatening arrhythmia. Given the complexity of the root cause of the disease, a combination of clinical diagnosis and drug screening using patient-derived cardiomyocytes represents a more effective way to identify potential cures. We identified a long QT syndrome patient carrying a heterozygous KCNQ1 c.656G>A mutation and a heterozygous TRPM4 c.479C>T mutation. Implantation of implantable cardioverter defibrillator in combination with conventional medication demonstrated limited success in ameliorating long-QT-syndrome-related symptoms. Frequent defibrillator discharge also caused deterioration of patient quality of life. Aiming to identify better therapeutic agents and treatment strategy, we established a patient-specific iPSC line carrying the dual mutations and differentiated these patient-specific iPSCs into cardiomyocytes. We discovered that both verapamil and lidocaine substantially shortened the QT interval of the long QT syndrome patient-specific cardiomyocytes. Verapamil treatment was successful in reducing defibrillator discharge frequency of the KCNQ1/TRPM4 dual mutation patient. These results suggested that verapamil and lidocaine could be alternative therapeutic agents for long QT syndrome patients that do not respond well to conventional treatments. In conclusion, our approach indicated the usefulness of the in vitro disease model based on patient-specific iPSCs in identifying pharmacological mechanisms and drug screening. The long QT patient-specific iPSC line carrying KCNQ1/TRPM4 dual mutations also represents a tool for further understanding long QT syndrome pathogenesis.

The Use of Intravenous Lidocaine in the Setting of Chronic Dofetilide Overdose: A Case Report

Managing the risks and consequences of long QT syndrome can be challenging. Multiple factors contribute to the prolongation of the heart-rate corrected QT (QTc) interval including many drug-drug and drug-disease state interactions. Current literature is often focused on avoiding dysrhythmias with limited guidance on acute management strategies. Here we describe a case of QTc prolongation to 616 msec (Bazett's formula) in the setting of chronic dofetilide overdose due to a possible prescription error. Our case was complicated by alcohol withdrawal and electrolyte disturbances that progressed to patient cardiac arrest in the emergency department. Dofetilide overdose was identified through pharmacist-initiated medication reconciliation and lidocaine was recommended as an alternative to amiodarone during advanced cardiac life support (ACLS). This case highlights the importance of reviewing outpatient medication records as well as avoiding drug-drug interactions during ACLS. Due to the potential for additive QTc prolongation, we recommend using lidocaine as the preferred antiarrhythmic in ACLS algorithms where drug induced QTc prolongation is suspected.

Effects of Lidocaine Oropharyngeal Spray Applied Before Endotracheal Intubation on QT Dispersion in Patients Undergoing Coronary Artery Bypass Grafting: A Prospective Randomized Controlled Study

OBJECTIVE

To investigate the effects of lidocaine oropharyngeal spray applied before endotracheal intubation on hemodynamic responses and electrocardiographic parameters in patients undergoing coronary artery bypass grafting.

METHODS

A total of 60 patients who underwent coronary artery bypass grafting surgery were included in this prospective randomized controlled study. Patients were randomly divided into two groups, the topical lidocaine group (administration of 10% lidocaine oropharyngeal spray, five minutes before laryngoscopy and endotracheal intubation) and the control group. Both groups were compared with each other in terms of main hemodynamic parameters including mean arterial pressure and heart rate, as well as P and QT wave dispersion durations, before and after endotracheal intubation.

RESULTS

The groups were similar in terms of age, gender, and other demographics and basic clinical characteristics. There was a statistically significant difference between the groups in terms of QT dispersion durations after laryngoscopy and endotracheal intubation. The increase in QT dispersion duration was not statistically significant in the topical lidocaine group, whereas the increase in QT dispersion duration was statistically significant in the control group. When the groups were compared in terms of P wave dispersion durations, there were significant decreases in both groups, but there was no significant difference between the groups.

CONCLUSION

Our study revealed that the topical lidocaine administration before endotracheal intubation prevented increase of QT dispersion duration in patients undergoing coronary artery bypass grafting.

TRIAL REGISTRATION

NCT03304431.

Modulating Perioperative Ventricular Excitability

Ventricular arrhythmias are associated with significant morbidity and mortality. In the perioperative period, more than 10% of patients undergoing a general anesthetic have an abnormal heart rhythm. Arrhythmia development is a dynamic interplay between an arrhythmogenic substrate, myocardial electrophysiologic properties, modifying factors, and triggering factors. Imbalances in the autonomic nervous system can lead to increased myocardial excitability, which is a major contributor to the pathophysiology of ventricular tachyarrhythmias. Myocardial excitability and ventricular arrhythmogenesis is modulated perioperatively through hemodynamic management, electrolyte balance, anesthetic agents, or regional anesthetic and surgical techniques.

Effects of esmolol on QTc interval changes during tracheal intubation: a systematic review

INTRODUCTION AND AIMS

Esmolol is an ultra-short-acting β₁ antagonist that has been shown to attenuate the corrected QT (QTc) interval prolongation associated with laryngoscopy and endotracheal intubation (LTI). Prolongation of the QTc interval can precipitate arrhythmias, the most serious of which is torsades de pointes . The aim of this systematic review was to compare esmolol and placebo on QTc changes occurring during LTI.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane Registry of Clinical Trials and CINAHL databases (up to August 2018) were screened for randomised controlled trials comparing esmolol and placebo on QTc changes during LTI in cardiac and non-cardiac surgeries. The primary outcome was QTc changes during LTI and secondary outcome was related to adverse effects from esmolol such as bradycardia and hypotension.

RESULTS

Seven trials were identified involving 320 patients, 160 patients receiving esmolol or placebo apiece. A shortening of the QTc post-LTI was evident in the esmolol group compared with the placebo in four studies. Compared with the baseline, the QTc was reduced post-LTI in the esmolol group. In the placebo group, the QTc was prolonged compared with the baseline post LTI. Nonetheless, esmolol did not prevent QTc prolongation in the remaining three studies, and much of this was attributed to employing QTc prolonging agents for premedication and anaesthetic induction. No significant adverse events were noted.

CONCLUSION

Compared with placebo, esmolol reduced the LTI-induced QTc prolongation when current non-QTc prolonging agents were chosen for tracheal intubation. Future studies should explore whether transmural dispersion (a marker of torsadogenicity) is also affected during LTI by analysing parameters such as the Tp-e interval (interval between the peak to the end of the T-wave) and Tp-e/QTc (rate corrected Tp-e interval).

TRIAL REGISTRATION NUMBER

CRD42018090282.

The effects of intravenous anesthetics on QT interval during anesthetic induction with desflurane

Introduction

This study aimed to determine the effects of the interaction between intravenous anesthetics and desflurane on the QT interval.

Methods

Fifty patients who underwent lumbar spine surgery were included. The patients received 3 μg/kg fentanyl and were randomly divided into two groups: group P patients received 1.5 mg/kg propofol and group T patients received 5 mg/kg thiamylal 2 min after fentanyl injection. All patients received rocuronium and desflurane (6% inhaled concentration) after loss of consciousness. Tracheal intubation was performed 3 min after rocuronium injection. Heart rate (HR), mean arterial pressure (MAP), bispectral index score (BIS), and the heart rate-corrected QT (QTc) interval on a 12-lead electrocardiograms were recorded before fentanyl injection (T1), 2 min after fentanyl injection (T2), 1 min after propofol or thiamylal injection (T3), immediately before intubation (T4), and 2 min after intubation (T5).

Results

There were no significant intergroup differences in patient characteristics. BIS and MAP decreased after anesthesia induction in both groups. MAP values at T3, T4, and T5 in group T were higher than those in group P. HR did not change over time or differ between the groups. The QTc intervals at T4 and T5 in group T were longer than those at T1. In group P, the QTc interval at T3 was significantly shorter than that at T1. The QTc intervals at T3, T4, and T5 in group T were significantly longer than those in group P.

Conclusions

A propofol injection could counteract the QTc interval prolongation during desflurane anesthesia induction.

Trial registration

UMIN Clinical Trials Registry database reference number: UMIN000023707. This study was registered on August 21, 2016.

Reference values of six-limb-lead electrocardiogram in conscious Labrador retriever dogs

Breed-wise standard electrocardiographic values in dogs have been reported as there is variation in body and chest conformation, which limits the application of data of one breed for other breed. Labrador retrievers being originated from hunting dogs, their electrocardiogram (ECG) values might be different from standard normal range of other dog breeds. So, the purpose of the present study was to determine the standard ECG of Labrador retrievers and to check effect of body weight, gender and breed upon different ECG parameters. Six-lead ECGs, three bipolar standard limb leads (I, II and III) and three augmented unipolar limb leads (aVR, aVL and aVF), were taken from 24 Labrador retrievers positioned in right lateral recumbency without any chemical restraint. Amplitude and duration of P wave and QRS complex, PR interval, QT interval and mean electrical axis and heart rate were measured in each recording. Non-significant effect of gender and body weight was seen on all the ECG waves. Deep Q waves in Leads I, II and aVF and variation in relation to QRS pattern were noted. It was concluded that retrievers had a specific shape of QRS complex which must be considered when evaluating a patient suspected of having cardiac disease. However, amplitude and durations of different ECG waves in all the six leads were statistically not affected by gender or body weight.

Comparison of the effects of various airway devices on hemodynamic response and QTc interval in rabbits under general anesthesia

In this study, we aimed to compare the effects of various airway devices on QTc interval in rabbits under general anesthesia. The subjects were randomly separated into four groups: Group ETT, Group LMA, Group PLA, Group V-gel. Baseline values and hearth rate, mean arterial pressure and ECG was obtained at the 1st, 5th and 30th minutes after administration of anesthesia and placement of airway device and, QTc interval was evaluated. Difference was observed between ET group and V-gel group in the 5th minute mean arterial pressure values (p < 0.05). It was observed that QTc intervals at the 1st and 5th minute in the ET group significantly increased when compared with the other groups (p < 0.05). Again, it was observed that QTc interval of ET group at the 15th and 30th minute was longer when compared with PLA and V-gel groups (p < 0.05). It was also observed that QTc interval of LMA Group at the 5th minute after intubation significantly increased when compared with V-gel group (p < 0.05). It was observed that HR values of ETT group at the 1st, 5th and 15th minutes after intubation increased with regards to PLA and V-gel groups (p < 0.05). It was determined that the 30th minute hearth rate of ETT group was higher when compared to V-gel group (p < 0.05).

CONCLUSION

In our study we observed that V-gel Rabbit affected both hemodynamic response and QT interval less than other airway devices.

Lidocaine administration before tracheal extubation cannot reduce post-operative cognition disorders in elderly patients

Background:

Cognitive dysfunction after surgery is common in elderly patients. Many factors such as anesthetic drugs can cause complication in this surgery. Lidocaine is one of the drugs commonly used during anesthesia. So, we designed this study to find out cognitive effect of lidocaine in elderly patients undergoing non-cardiac surgeries.

Materials and Methods:

In this double-blinded clinical trial, we enrolled 70 patients older than 65 years age undergoing urologic or orthopedic surgeries, were divided in two groups. Patients randomly received intravenous lidocaine (1.5 mg/kg) or normal saline in the same volume immediately before extubation. Mini mental state examination (MMSE) test was used to evaluate cognitive state at discharge time, 6 and 24 h after surgery.

Results:

Mean MMSE scores at the time of discharge from recovery room in lidocaine and saline groups were 22.4 ± 4.5 vs. 22.1 ± 4.4, P = 0.755, respectively. It was significantly lower than MMSE before surgery, 6 and 24 h after the operation. The mean MMSE scores and frequency distribution of intensity of cognitive impairments were not significantly different between two groups at different times.

Conclusion:

Bolus intravenous lidocaine before extubation, did not affect cognitive states in elders undergoing non-cardiac surgery. Effect of lidocaine on cardiac surgeries is clear, but in non-cardiac surgeries, lidocaine has no clinical effects. So, more studies with different doses of lidocaine and different assessment methods are recommended.

Effect of experimental hyperlipidaemia on the electrocardiographic effects of repeated doses of halofantrine in rats

BACKGROUND AND PURPOSE

Halofantrine can cause a prolongation of the cardiac QT interval, leading to serious ventricular arrhythmias. Hyperlipidaemia elevates plasma concentration of halofantrine and may influence its tissue uptake. The present study examined the effect of experimental hyperlipidaemia on QT interval prolongation induced by halofantrine in rats.

EXPERIMENTAL APPROACH

Normolipidaemic and hyperlipidaemic rats (induced with poloxamer 407) were given 4 doses of halofantrine (i.v., 4-40 mg·kg(-1)·d(-1)) or vehicle every 12 h. Under brief anaesthesia, ECGs were recorded before administration of the vehicle or drug and 12 h after the first and last doses. Blood samples were taken at the same time after the first and last dose of halofantrine. Hearts were also collected 12 h after the last dose. Plasma and heart samples were assayed for drug and desbutylhalofantrine using a stereospecific method.

KEY RESULTS

In the vehicle group, hyperlipidaemia by itself did not affect the ECG. Compared to baseline, QT intervals were significantly higher in both normolipidaemic and hyperlipidaemic rats after halofantrine. In hyperlipidaemic rats, plasma but not heart concentrations of the halofantrine enantiomers were significantly higher compared to those in normolipidaemic rats. Despite the lack of difference in the concentrations of halofantrine in heart, QT intervals were significantly higher in hyperlipidaemic compared to those in normolipidaemic rats.

CONCLUSIONS AND IMPLICATIONS

The unbound fraction of halofantrine appeared to be the controlling factor for drug uptake by the heart. Our data suggested a greater vulnerability to halofantrine-induced QT interval prolongation in the hyperlipidaemic state.

Recurrent torsades de pointes in association with a very low calorie diet

The use of very low calorie diets under medical supervision is becoming increasingly popular in the UK, as the incidence of obesity continues to rise. We report the case of torsades de pointes developing during such a diet. Torsades de pointes has been reported in association with very low calorie diets in the past but to our knowledge, this is the first report since the introduction of newer, nutritionally complete versions of the diet. We review the intensive care management of recurrent torsades de pointes resistant to standard therapy and its relationship to dieting and obesity.