The possible role of propofol in drug-induced torsades de pointes: A real-world single-center analysis

Development and Validation of Inpatient Hypoglycemia Models Centered Around the Insulin Ordering Process

BACKGROUND

The insulin ordering process is an opportunity to provide clinicians with hypoglycemia risk predictions, but few hypoglycemia models centered around the insulin ordering process exist.

METHODS

We used data on adult patients, admitted in 2019 to non-ICU floors of a large teaching hospital, who had orders for subcutaneous insulin. Our outcome was hypoglycemia, defined as a blood glucose (BG) <70 mg/dL within 24 hours after ordering insulin. We trained and evaluated models to predict hypoglycemia at the time of placing an insulin order, using logistic regression, random forest, and extreme gradient boosting (XGBoost). We compared performance using area under the receiver operating characteristic curve (AUCs) and precision-recall curves. We determined recall at our goal precision of 0.30.

RESULTS

Of 21 052 included insulin orders, 1839 (9%) were followed by a hypoglycemic event within 24 hours. Logistic regression, random forest, and XGBoost models had AUCs of 0.81, 0.80, and 0.79, and recall of 0.44, 0.49, and 0.32, respectively. The most significant predictor was the lowest BG value in the 24 hours preceding the order. Predictors related to the insulin order being placed at the time of the prediction were useful to the model but less important than the patient's history of BG values over time.

CONCLUSIONS

Hypoglycemia within the next 24 hours can be predicted at the time an insulin order is placed, providing an opportunity to integrate decision support into the medication ordering process to make insulin therapy safer.

Suppression of Electrographic Seizures Is Associated with Amelioration of QTc Interval Prolongation in Patients with Traumatic Brain Injury

Introduction: Disorders in electroencephalography (EEG) are commonly noted in patients with traumatic brain injury (TBI) and may be associated with electrocardiographic disturbances. Electrographic seizures (ESz) are the most common features in these patients. This study aimed to explore the relationship between ESz and possible changes in QTc interval and spatial QRS-T angle both during ESz and after ESz resolution. Methods: Adult patients with TBI were studied. Surface 12-lead ECGs were recorded using a Cardiax device during ESz events and 15 min after their effective suppression using barbiturate infusion. The ESz events were diagnosed using Masimo Root or bispectral index (BIS) devices. Results: Of the 348 patients considered for possible inclusion, ESz were noted in 72, with ECG being recorded in 21. Prolonged QTc was noted during ESz but significantly ameliorated after ESz suppression (540.19 ± 60.68 ms vs. 478.67 ± 38.52 ms, p < 0.001). The spatial QRS-T angle was comparable during ESz and after treatment. Regional cerebral oximetry increased following ESz suppression (from 58.4% ± 6.2 to 60.5% ± 4.2 (p < 0.01) and from 58.2% ± 7.2 to 60.8% ± 4.8 (p < 0.05) in the left and right hemispheres, respectively). Conclusion: QTc interval prolongation occurs during ESz events in TBI patients but both it and regional cerebral oximetry are improved after suppression of seizures.

Perioperative Implications of the 2020 American Heart Association Scientific Statement on Drug-Induced Arrhythmias-A Focused Review

The recently released American Heart Association (AHA) scientific statement on drug-induced arrhythmias discussed medications commonly associated with bradycardia, supraventricular tachycardias, and ventricular arrhythmias. The foundational data for this statement were collected from general outpatient and inpatient populations. Patients undergoing surgical and minimally invasive treatments are a unique subgroup, because they may experience hemodynamic changes associated with anesthesia and their procedure, receive multiple drug combinations not given in either inpatient or outpatient settings, or experience postprocedural inflammatory syndromes. Accordingly, the generalizability of the AHA scientific statement to this perioperative population is unclear. This focused review highlights important aspects of the new AHA scientific statement and their application to the perioperative setting. The authors review medications frequently encountered and given by anesthesiologists and their risk of drug-induced arrhythmias and discuss common anesthetic and adjunctive medications and their associated risks of bradycardia, atrial fibrillation, torsades de pointes, and drug-induced Brugada syndrome. In many instances, the risk of arrhythmia reported by the AHA scientific statement in the general population appeared to be higher than found in perioperative arenas. Furthermore, the authors discuss the arrhythmia risk of additional medications commonly ordered or administered by anesthesiologists that are not included in the AHA scientific statement. As patient and procedural complexity increases and novel anesthetic combinations propagate, further research and observational studies will be required to delineate further perioperative risks for drug-induced arrhythmia.

Elevation of propofol sensitivity of cardiac IKs channel by KCNE1 polymorphism D85N

BACKGROUND AND PURPOSE

The slowly activating delayed rectifier K⁺ channel (I_Ks ), composed of pore-forming KCNQ1 α-subunits and ancillary KCNE1 β-subunits, regulates ventricular repolarization in human heart. Propofol, at clinically used concentrations, modestly inhibits the intact (wild-type) I_Ks channels and is therefore unlikely to appreciably prolong QT interval in ECG during anaesthesia. However, little information is available concerning the inhibitory effect of propofol on I_Ks channel associated with its gene variants implicated in QT prolongation. The KCNE1 single nucleotide polymorphism leading to D85N is associated with drug-induced QT prolongation and therefore regarded as a clinically important genetic variant. This study examined whether KCNE1-D85N affects the sensitivity of I_Ks to inhibition by propofol.

EXPERIMENTAL APPROACH

Whole-cell patch-clamp and immunostaining experiments were conducted in HEK293 cells and/or mouse cardiomyocyte-derived HL-1 cells, transfected with wild-type KCNQ1, wild-type or variant KCNE1 cDNAs.

KEY RESULTS

Propofol inhibited KCNQ1/KCNE1-D85N current more potently than KCNQ1/KCNE1 current in HEK293 cells and HL-1 cells. Immunostaining experiments in HEK293 cells revealed that pretreatment with propofol (10 μM) did not appreciably affect cell membrane expression of KCNQ1 and KCNE1 proteins in KCNQ1/KCNE1 and KCNQ1/KCNE1-D85N channels.

CONCLUSION AND IMPLICATIONS

The KCNE1 polymorphism D85N significantly elevates the sensitivity of I_Ks to inhibition by propofol. This study detects a functionally important role of KCNE1-D85N polymorphism in conferring genetic susceptibility to propofol-induced QT prolongation and further suggests the possibility that the inhibitory action of anaesthetics on ionic currents becomes exaggerated in patients carrying variants in genes encoding ion channels.

Torsades de pointes in SARS-CoV-2 (COVID-19) pneumonia: medicine reconciliation and careful monitoring of QTc interval may help prevent cardiac complications

Hydroxychloroquine has been widely prescribed to treat patients with COVID-19 pneumonia. A 73-year-0ld woman with COVID-19 pneumonia was treated with dexamethasone and hydroxychloroquine. Her home medications, citalopram and donepezil, were continued. The ECG prior to starting hydroxychloroquine showed normal sinus rhythm with prolonged corrected QT (QTc) of 497 ms, due to citalopram and donepezil therapy. Repeat ECG on days 3 and 4 of hydroxychloroquine therapy showed significantly prolonged QTc of 557 ms and 538 ms, respectively, despite normal serum electrolytes. All QT-prolonging medications including hydroxychloroquine were discontinued on day 4; however, she suffered a transient torsades de pointes lasting for about 15 s, which resolved before any intervention. QTc improved to 477 ms, after discontinuation of QT-prolonging medications. The patient had QTc prolongation and torsades de pointes due to therapy with multiple QT-prolonging medications. Medicine reconciliation and careful monitoring of QTc may help prevent cardiac complications in patients with COVID-19 treated with hydroxychloroquine.

Perianesthesia Implications and Considerations for Drug-Induced QT Interval Prolongation

Prolongation of the QT interval can predispose patients to fatal arrhythmias such as torsade de pointes. While arrhythmias can occur spontaneously in patients with a genetic predisposition, drugs such as ondansetron and droperidol, which are frequently used in the perioperative period, have been implicated in the prolongation of the QT interval. As the list of medications that cause QT prolongation grows, anesthesia providers and perioperative nurses must be informed regarding the importance of the QT interval. This article reviews the physiology and measurement of the QT interval, the risk factors of QT prolongation, the mechanism of drug-induced QT prolongation, and perioperative considerations for patient care.

Polymorphic Ventricular Tachycardia Secondary to Subarachnoid Haemorrhage: A Rare Occurrence in the Setting of Normal QTc

Subarachnoid hemorrhage (SAH) is a neurologic emergency associated with high mortality rate. Polymorphic ventricular tachycardia (VT) is a rare arrhythmia. It can occur in any setting of a long QT interval and bradycardia. This may result from a cardiomyopathy (both ischemic and non-ischemic), acute coronary ischemia, congenital long QT syndrome, electrolyte disturbances and cerebrovascular diseases. We report a rare case of polymorphic VT of unclear etiology with a normal corrected QT, likely secondary to SAH. Reports associating ventricular arrhythmias and SAH have been described, yet the mechanism of this association remains unclear. Previous observations of VT seen in patients with SAH suggest a relationship with QT prolongation. The QT interval, however, remained normal in our patient, suggesting an alternative and unknown mechanism for the polymorphic VT.