Amiodarone-induced acute lung toxicity in an ICU setting

Acute amiodarone-induced pulmonary toxicity in adult ICU patients with new-onset atrial fibrillation-A systematic review

BACKGROUND

New-onset atrial fibrillation or flutter (NOAF) is a common arrhythmia in adult intensive care unit (ICU) patients. Intravenous amiodarone is one of the most used anti-arrhythmic drugs, despite its risk of inducing acute amiodarone-induced pulmonary toxicity (APT). We aimed to outline the body of evidence on acute APT in ICU patients with NOAF.

METHODS

We performed a systematic search using the population, intervention, comparison, and outcome (PICO) approach. We included studies of adults admitted to the ICU, who developed NOAF during their ICU stay, were treated with amiodarone, and reported on acute APT, irrespective of research design. The CASE guidelines were applied to evaluate the quality of the included studies, and study results are reported in accordance with the preferred reporting items for systematic reviews and meta-analyses.

RESULTS

No randomised controlled trials or observational studies were identified. Nine case reports and one retrospective case series of fatal outcomes in ICU patients treated with amiodarone for NOAF constituted the evidence base. The quality of the included studies was high with a mean of 10 (range 8-12) of the 13 CASE guideline criteria fulfilled. The studies included a total of 16 critically ill adults who was diagnosed with acute APT after a mean of 9 days (range 2-20 days) following initiation of amiodarone with a mean total dose of amiodarone of 4553 mg (range 1100-13,500 mg) predominantly administrated intravenously. Three out of nine patients in the case reports died in the ICU during the amiodarone treatment. No long-term follow-up was conducted for the survivors.

CONCLUSION

Acute APT in adult ICU patients treated with amiodarone for NOAF is poorly described and is based on a total of 16 reported cases. Additional studies assessing the safety of amiodarone in critically ill adults with NOAF in the ICU is warranted.

Early amiodarone pneumonitis: A case report

Consider amiodarone pneumonitis as an important differential diagnosis of ARDS, especially in clinically ill patients who recently received Intravenous amiodarone.

Acute Amiodarone Pulmonary Toxicity

Amiodarone is an effective antiarrhythmic that frequently is used during the perioperative period. Amiodarone possesses a significant adverse reaction profile. Amiodarone-induced pulmonary toxicity (AIPT) is among the most serious adverse effects and is a leading cause of death associated with its use. Despite significant advances in the understanding of AIPT, its etiology and pathogenesis remain incompletely understood. The diagnosis of AIPT is one of exclusion. The clinical manifestations of AIPT are categorized broadly as acute, subacute, and chronic. Acute AIPT is a rarer and more aggressive form of the disease, most often encountered in cardiothoracic surgery. Acute respiratory distress syndrome (ARDS) is the predominating pattern of amiodarone's acute pulmonary toxicity. The incidence, risk factors, pathogenesis, and diagnosis of acute AIPT are speculative. Early cardiothoracic literature investigating AIPT often attributed amiodarone to the development of postoperative ARDS. Subsequent studies have found no association between amiodarone and acute AIPT and ARDS development. As a drug that is frequently prescribed to a patient population deemed most at risk for this fatal disease, the conflicting evidence on acute AIPT needs further investigation and clarification.

Amiodarone use to prevent postoperative atrial fibrillation after cardiac surgery

Atrial fibrillation is the most common complication occurring after coronary artery bypass graft surgery. The purpose of this article was to examine the incidence of, risk factors related to, and complications caused by postoperative atrial fibrillation. The pathophysiology and treatment of atrial fibrillation and postoperative atrial fibrillation will also be discussed.

No elevation of glutathione S-transferase-a1-1 by amiodarone loading in intensive care unit patients with atrial fibrillation

Hepatocellular toxicity is a putative side-effect of amiodarone. The hepatic detoxification enzyme glutathione S-transferase-A1-1 (GSTA1-1) is a sensitive indicator of hepatocellular damage. We investigated the occurrence of subclinical liver injury, as measured by plasma GSTA1-1 in intensive care unit patients with atrial fibrillation receiving amiodarone. Sixteen haemodynamically stable intensive care unit patients with atrial fibrillation were treated with amiodarone intravenously. Patients were given a loading dose of 150 mg followed by another 150 mg followed by a continuous infusion of 1200 mg/hour if atrial fibrillation persisted. Blood samples for GSTA1-1 (measured by an enzyme-linked immunosorbent assay) were taken at zero, one, three, six, 12 and 24 hours, transaminases and bilirubin at zero, six, 12 and 24 hours. Blood pressure and heart rate were continuously monitored. Effects were analysed for time-dependent changes (one-way analysis of variance for repeated measures). Blood pressure increased from 125 +/- 8/60 +/- 3 mmHg at t = 0 to 144 +/- 9/66 +/- 4 mmHg at t = 24 hours (P < 0.05), heart rate decreased from atrial fibrillation 124 +/- 5 to sinus rhythm 86 +/- 6 beats per minute (P < 0.05). There was no significant elevation of GSTA1-1, transaminases or bilirubin during the observation period of 24 hours. Amiodarone does not cause elevation of GSTA1-1 as a marker of subclinical liver injury in haemodynamically stable intensive care unit patients with atrial fibrillation.

Effects of amiodarone on lung tissue mechanics and parenchyma remodeling

We studied the results of chronic oral administration of amiodarone on in vitro lung tissue mechanics, light and electron microscopy. Fifteen Wistar male rats were divided into three groups. In control (CTRL) group animals received saline (0.5 mL/day). In amiodarone (AMIO) groups, amiodarone was administered by gavage at a dose of 175 mg/kg 5 days per week for 6 (6AMIO) or 12 weeks (12AMIO). Lung tissue strips were analyzed 24h after the last drug administration. Tissue resistance and elastance were higher in 6AMIO and 12AMIO than in CTRL, while hysteresivity was similar in all groups. Total amount of collagen fibers in lung parenchyma increased progressively with the time course of the lesion. However, at 6 weeks there was an increase in the amount of type III collagen fibers, while in 12AMIO mainly type I collagen fibers were found. In our study amiodarone increased lung tissue impedance that was accompanied by matrix remodeling and lesion of type II pneumocytes.

Efficacy of magnesium-amiodarone step-up scheme in critically ill patients with new-onset atrial fibrillation: a prospective observational study

Amiodarone is considered a first-choice antiarrhythmic drug in critically ill patients with new-onset atrial fibrillation (AF). However, evidence supporting the use of this potentially toxic drug in critically ill patients is scarce. Magnesium sulphate (MgSO4) has shown to be effective for both rate and rhythm control, to act synergistically with antiarrhythmic drugs, and to prevent proarrhythmia. Treatment with MgSO4 may reduce the need for antiarrhythmic drugs such as amiodarone in critically ill patients with new-onset atrial fibrillation. The efficacy of a new institutional protocol was evaluated. Patients were treated with a new institutional protocol for new-onset atrial fibrillation in critically ill patients. An MgSO4 bolus (0.037 g/kg body weight in 15 minutes) was followed by continuous infusion (0.025 g/kg body weight/h). Intravenous amiodarone (loading dose 300 mg, followed by continuous infusion of 1200 mg/24 h) was given to those not responding to MgSO4 within 1 hour. Clinical response was defined as conversion to sinus rhythm or decrease in heart rate <110 beats/min. Sixteen of the 29 patients responded to MgSO4 monotherapy, whereas the addition of amiodarone was needed in 13 patients. Median (range) time until conversion to sinus rhythm after MgSO4 was 2 (1-45) hours. Median (range) conversion time in patients requiring amiodarone was 4 (2-78) hours, and median (range) conversion time in all patients was 3 (1-78) hours. The 24-hour conversion rate was 90%. Relapse atrial fibrillation was seen in 7 patients. The magnesium-amiodarone step-up scheme reduces the need for amiodarone, effectively converts new-onset atrial fibrillation into a sinus rhythm within 24 hours, and seems to be safe in critically ill patients.