Perioperative cardiac arrhythmias

Examining the arrhythmogenicity of dobutamine when used in conjunction with isoflurane in horses: A retrospective study at a single university teaching hospital

BACKGROUND

Dobutamine is used to treat hypotension in isoflurane-anaesthetised horses but may produce arrhythmias. Halothane is a volatile anaesthetic that was, historically, widely used in horses, but in one study, 56 of 200 halothane-anaesthetised horses (28%) developed arrhythmias after dobutamine administration. Although isoflurane has largely replaced halothane, it is unknown how isoflurane and dobutamine interact in the development of arrhythmias.

METHODS

The medical records of horses undergoing general anaesthesia at the University of Georgia Veterinary Teaching Hospital in 2015 were reviewed retrospectively. Cases were selected if isoflurane was used as the maintenance inhalant anaesthetic agent and dobutamine was administered for the treatment of hypotension. Any instances of arrhythmia occurring following dobutamine administration were recorded.

RESULTS

Arrhythmia occurred after dobutamine administration in six out of a total of 148 horses (4.0%).

LIMITATIONS

The retrospective nature of this study and the fact that the horses were anaesthetised at a single institution might limit the extent to which the findings can be generalised.

CONCLUSION

Compared to halothane, isoflurane has a much lower incidence of arrhythmia when used with dobutamine. However, a larger-scale study is needed to identify risk factors associated with horses developing an arrhythmia induced by isoflurane in combination with dobutamine.

Effects and mechanisms of dexmedetomidine preconditioning on isoproterenol-induced ventricular arrhythmias

Dexmedetomidine (DEX) is commonly used in clinical practice because of its sedative, analgesic, antisympathetic, hemodynamic stabilization and antianxiety effects. Previous clinical studies have demonstrated that DEX plays a role in both the prevention and treatment of perioperative arrhythmias. However, the precise mechanisms underlying the effects of DEX remain unclear. Furthermore, few studies have examined the effect of DEX on cardiac electrophysiology. ECG recording was performed in vivo and ex vivo on C57 mice. Simultaneous recording of membrane voltage (Vm) and [Ca2+]i changes was achieved with dual-dye optical mapping, in which voltage- and Ca2+-sensitive dyes are employed. Simultaneous programmed electrical stimulation was used to pacing and induce arrhythmias. Simulating catecholamine-induced arrhythmias with isoprotereno (ISO) and preconditioning with DEX to investigate the antiarrhythmic effects of DEX. Our findings demonstrated that ISO increased the incidence of ventricular tachycardia or ventricular fibrillation in mice during rapid pacing stimulation. DEX preconditioning reduced the incidence of ISO-induced ventricular arrhythmias. Optical mapping with simultaneous recordings of dual dyes (Vm dye and intracellular Ca2+ dye) revealed that DEX pretreatment attenuated the ISO-induced shortening of action potential duration (APD), calcium transient duration (CaTD), and time-to-peak (TTP) of calcium transients, as well as the ISO-induced increase in repolarization heterogeneity. DEX also slowed the conduction velocity. More importantly, DEX preconditioning significantly reduced the calcium transient alternans ratio at 80-ms, 70-ms, and 60-ms pacing cycles. These findings suggest that DEX preconditioning can reduce the incidence of ventricular arrhythmias induced by acute stress simulated by ISO. Prolongation of action potential duration and calcium transient duration and the maintenance of intracellular calcium homeostasis may be the electrophysiological mechanisms involved.

Early Impressions and Adoption of the AtriAmp for Managing Arrhythmias Following Congenital Heart Surgery

AtriAmp is a new medical device that displays a continuous real-time atrial electrogram on telemetry using temporary atrial pacing leads. Our objective was to evaluate early adoption of this device into patient care within our pediatric intensive care unit (PICU). This is a qualitative study using inductive analysis of semi-structured interviews to identify dominant themes. The study was conducted in a single-center, tertiary, academic 21-bed mixed PICU. The subjects were PICU multidisciplinary team members (Pediatric Cardiac Intensivists, PICU Nurse Practitioners, PICU nurses and Pediatric Cardiologists) who were early adopters of the AtriAmp (n = 14). Three prominent themes emerged: (1) Accelerated time from arrhythmia event to diagnosis and treatment; (2) Increased confidence in the accuracy of providers' arrhythmia diagnosis; and (3) Improvement in the ability to educate providers about post-operative arrhythmias. Providers also noted some learning curves, but none compromised medical care or clinical workflow. Insights from early adopters of AtriAmp signal the need for simplicity and fidelity in new PICU technologies. Our research suggests that such technologies can be pivotal to the support and growth of multi-disciplinary teams, even among those who do not participate in early implementation. Further research is needed to understand when and why novel technology adoption becomes widespread in high-stakes settings.

Post-Acute COVID-19 Syndrome for Anesthesiologists: A Narrative Review and a Pragmatic Approach to Clinical Care

Post-acute coronavirus disease 2019 (COVID-19) syndrome is a novel, poorly understood clinical entity with life-impacting ramifications. Patients with this syndrome, also known as "COVID-19 long-haulers," often present with nonspecific ailments involving more than one body system. The most common complaints include dyspnea, fatigue, brain fog, and chest pain. There currently is no single agreed-upon definition for post-acute COVID-19 syndrome, but most agree that criterion for this syndrome is the persistence of mental and physical health consequences after initial infection. Given the millions of acute infections in the United States over the course of the pandemic, perioperative providers will encounter these patients in clinical practice in growing numbers. Symptoms of the COVID-19 long-haulers should not be minimized, as these patients are at higher risk for postoperative respiratory complications and perioperative mortality for up to seven weeks after initial illness. Instead, a cautious multidisciplinary preoperative evaluation should be performed. Perioperative care should be viewed through the prism of best practices already in use, such as avoidance of benzodiazepines in patients with cognitive impairment and use of lung-protective ventilation. Recommendations especially relevant to the COVID-19 long-haulers include assessment of critical care myopathies and neuropathies to determine suitable neuromuscular blocking agents and reversal, preoperative workup of insidious cardiac or pulmonary pathologies in previously healthy patients, and, thorough medication review, particularly of anticoagulation regimens and chronic steroid use. In this article, the authors define the syndrome, synthesize the available scientific evidence, and make pragmatic suggestions regarding the perioperative clinical care of COVID-19 long-haulers.

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.

Hypokalemia Leading to Postoperative Critical Arrhythmias: Case Reports and Literature Review

Perioperative arrhythmias can develop due to many reasons, rarely life-threatening, but hypokalemia plays an important role in their development. We report two cases of severe postoperative hypokalemia leading to ventricular fibrillation (VF). Case 1: A young healthy lady developed perioperative severe hypokalemia leading to repeated episodes of VF requiring cardiopulmonary resuscitation (CPR), direct current (DC) shock and anti-arrhythmic therapy, apart from rapid replacement of intravenous potassium. She recovered fully without any neurological or cardiac sequelae. Case 2: A 78-year-old male patient, a known case of hypertension controlled with medications developed postoperative repeated VF due to hypokalemia requiring 210 mmol of potassium chloride, antiarrhythmic therapy, DC shock, and CPR. He recovered, but complicated into acute myocardial infarction requiring therapy. Perioperative severe hypokalemia can lead to life-threatening cardiac arrhythmias. Early recognition and aggressive correction are essential for better outcomes.

Complex Arrhythmias Due to Reversible Causes

Abnormalities in cardiac rhythm are caused by disorders of impulse generation, conduction, or a combination of the 2, and may be life-threatening because of a reduction in cardiac output or myocardial oxygenation. Cardiac arrhythmias are commonly classified as tachycardias (supraventricular or ventricular) or bradycardias. Bradycardias are uncommon in the critically ill patient and often are caused by an underlying reversible disorder (eg, hyperkalemia, drug toxicity). Supraventricular and ventricular tachycardias are more often encountered in the critically ill patient and often have underlying treatable disorders that precipitate their development (eg, hypokalemia, hypomagnesemia, antiarrhythmic proarrhythmia, myocardial ischemia).

Evaluating the Safety of Intraoperative Antiarrhythmics in Pediatric Cardiac Surgery Patients

Cardiac arrhythmias occurring during the intraoperative period for cardiac surgery have been associated with excess morbidity and mortality. Several antiarrhythmics have been utilized for the management of intraoperative arrhythmias. These antiarrhythmic medications can cause undesirable adverse outcomes in the intensive care setting. The incidence and treatment of adult intraoperative arrhythmias have been studied. In addition, the prevalence, risk factors, and optimal treatment of pediatric postoperative arrhythmias have also been studied. However, the literature has not been published on intraoperative antiarrhythmia treatment during pediatric cardiac surgery. The purpose of this study was to determine the safety of intraoperative antiarrhythmic medications utilized in pediatric cardiac surgery patients. This was a retrospective review of all patients who received an intraoperative antiarrhythmic in the cardiovascular operating room at Texas Children's Hospital. Patients were included if they underwent cardiovascular surgery from November 2008 to July 2013 and were excluded if antiarrhythmics were given intraoperatively for other indications (i.e., esmolol for hypertension) or if patients were older than 18 years of age. Safety of antiarrhythmic treatment was determined by the absence or presence of adverse events. Control or recurrence of the arrhythmia was analyzed as a secondary measure to help determine antiarrhythmic efficacy. A total of 45 patients were identified (53.3 % male). Patients were a median of 0.52 years at the time of surgery. Primary surgery types were tetralogy of Fallot repair (n = 6; 13.3 %) and ventricular septal defect closure (n = 5, 11.1 %). Thirty-one patients (68.9 %) had documented adverse events after the administration of antiarrhythmics. Most of these adverse events occurred after the administration of amiodarone (n = 16; 51.6 %) followed by esmolol (n = 15; 48.4 %). Fifty-one percent of the arrhythmias resolved in the operating room (n = 23), and nearly half (n = 19) of all patients were discharged home on an antiarrhythmic medication. A high incidence of adverse events was associated with intraoperative administration of antiarrhythmic medications.

Cardiac risk assessment: decreasing postoperative complications

Preoperative cardiac assessment helps identify patients undergoing noncardiac surgery who are at risk for significant postoperative cardiac complications and those who may benefit from additional preoperative evaluation and perioperative care. Advanced practice nurses can identify surgery- and patient-related risks by conducting a thorough health history and physical examination. Multiple risk indices and evidence-based guidelines are available to inform health care providers regarding patient evaluation and strategies to reduce postoperative cardiac risk. In general, preoperative tests are recommended only if the findings will influence medical therapy or perioperative monitoring or will require postponement of surgery until a cardiac condition can be corrected or stabilized. Medication management is a crucial component of the preoperative assessment; providers may need to initiate the use of beta-blockers and make decisions regarding continuing or withholding antiplatelet and anticoagulant therapy. Preoperative cardiac risk stratification, medication reconciliation, and device management are essential for providing safe care for patients.

Predictors of Functional Outcome after Intraoperative Cardiac Arrest

Background:

Few outcome data are available about intraoperative cardiac arrest (IOCA). The authors studied 90-day functional outcomes and their determinants in patients admitted to the intensive care unit after IOCA.

Methods:

Patients admitted to 11 intensive care units in a period of 2000–2013 were studied retrospectively. The main outcome measure was a day-90 Cerebral Performance Category score of 1 or 2.

Results:

Of the 140 patients (61 women and 79 men; median age, 60 yr [interquartile range, 46 to 70]), 131 patients (93.6%) had general anesthesia, 80 patients (57.1%) had emergent surgery, and 73 patients (52.1%) had IOCA during surgery. First recorded rhythms were asystole in 73 patients (52.1%), pulseless electrical activity in 44 patients (31.4%), and ventricular fibrillation/ventricular tachycardia in 23 patients (16.4%). Median times from collapse to cardiopulmonary resuscitation and return of spontaneous circulation were 0 min (0 to 0) and 10 min (5 to 20), respectively. Postcardiac arrest shock was identified in 114 patients (81.4%). Main causes of IOCA were preoperative complications (n = 46, 32.9%), complications of anesthesia (n = 39, 27.9%), and complications of surgical procedures (n = 36, 25.7%). On day 90, 63 patients (45.3%) were alive with Cerebral Performance Category score 1/2. Independent predictors of day-90 Cerebral Performance Category score 1/2 were day-1 Logistic Organ Dysfunction score (odds ratio, 0.78 per point; 95% CI, 0.71 to 0.87; P = 0.0001), ventricular fibrillation/tachycardia as first recorded rhythm (odds ratio, 4.78; 95% CI, 1.38 to 16.53; P = 0.013), and no epinephrine therapy during postcardiac arrest syndrome (odds ratio, 3.14; 95% CI, 1.29 to 7.65; P = 0.012).

Conclusions:

By day 90, 45% of IOCA survivors had good functional outcomes. The main outcome predictors were directly related to IOCA occurrence and postcardiac arrest syndrome; they suggest that the intensive care unit management of postcardiac arrest syndrome may be amenable to improvement.

Temporary cardiac arrest in patient under robotically assisted total thyroidectomy causing carotid sinus hypersensitivity -A case report-

Carotid sinus hypersensitivity (CSH) is an exaggerated response to carotid sinus baroreceptor stimulation. Bradycardia, hypotension, and syncope are common manifestations of CSH. A 31-year-old female patient was scheduled for a robotically assisted endoscopic total thyroidectomy. No problems occurred during anesthetic induction. Sudden cardiac arrest occurred near dissection of the diseased thyroid. However, while atropine was administered, the patient soon recovered to normal sinus rhythm. Subsequent bradycardia or hypotension was not followed until the end of surgery.