Accidental Intra-Arterial Infusion of Amiodarone in a Pediatric Patient With Atrial Ectopic Tachycardia.

To the Editor: In a recent issue of Critical Care Medicine, Witkowski et al (1) described a case of acute thrombotic occlusion of the brachial artery after intra-arterial administration of amiodarone. We recently encountered a similar case of accidental intraarterial administration of amiodarone via the femoral artery in the PICU. Our patient was a 4-year-old boy who presented with vomiting and pallor. He had a heart rate of 280 beats/ min and was given three doses of IV adenosine for supraventricular tachycardia. As there was no reversion to sinus rhythm, IV propranolol infusion was given. Subsequently, atrial ectopic tachycardia was diagnosed. Oral flecainide was administered, and serial synchronized cardioversion was performed unsuccessfully. He was intubated in view of cardiorespiratory compromise. Right femoral vascular access was secured using a triple-lumen catheter, with nonpulsatile flow observed. Through this catheter, amiodarone at 5 mg/kg was given followed by infusion at 15 μg/kg/min. Approximately 8 hours into the infusion, an arterial waveform was seen upon pressure wave transduction. A blood gas analysis confirmed that the catheter was intra-arterial. Throughout this period, no skin changes were observed at the infusion site, and the child was not distressed. Rate control had been achieved within 6 hours of this intra-arterial infusion. It was immediately stopped and converted to a peripheral venous catheter, and the catheter was removed. Close monitoring fortunately did not reveal any signs of limb ischemia, and he was eventually discharged well. Most cases of intra-arterial drug administration reported previously involved anesthetic and sedative agents (2). To date, two cases of inadvertent intra-arterial adenosine administered through the brachial artery have been reported, both in children with supraventricular tachycardia (2, 3). Aside from brief periods of pain and skin mottling, neither patient had adverse effects. This could be because the short half-life of adenosine causes it to be rapidly metabolized. With amiodarone, however, Witkowski et al (1) postulated that there was direct cytotoxic effect on the vessel wall causing endothelial damage and arterial thrombus formation. In our patient, amiodarone had been running for 8 hours intra-arterially with no clinical suspicion of vascular damage although there was no Doppler study 6. Grover S, Kate N: Assessment scales for delirium: A review. World J Psychiatry 2012; 2:58–70 7. Van Rompaey B, Elseviers MM, Van Drom W, et al: The effect of earplugs during the night on the onset of delirium and sleep perception: A randomized controlled trial in intensive care patients. Crit Care 2012; 16:R73 8. Litton E, Carnegie V, Elliott R, et al: The efficacy of earplugs as a sleep hygiene strategy for reducing delirium in the ICU: A systematic review and meta-analysis. Crit Care Med 2016; 44:992–999 The authors reply: Drs. Putzu and Belletti (1) correctly identify that p values were not reported for the primary or secondary outcomes. The relative risk (RR) of delirium as reported for the primary outcome was 0.59 (95% CI, 0.44–0.78). The associated p value is less than 0.001. It is unclear whether the provision of a p value in this setting adds value, given that the point estimates and associated 95% CIs are provided for all relevant outcome measures (2). Data on ICU length of stay were only available for three studies and were therefore insufficient for quantitative analysis (3–5). Participants per study are provided in Table 1. Events per study for this outcome and others are available from the primary articles, or alternatively, the database for metaanalysis can be provided on request. A score of between 20 and 24 in the validated NEECHAM confusion scale indicates mild delirium (6). This same range was described as “standardized” but labeled as “confusion” in the trial by Van Rompaey et al (7). Patients in this category were therefore included in our delirium meta analysis (8). The study by Van Rompaey et al (7) contributed 28% weighting to this meta analysis. Removing the study from the meta analysis did not substantially alter the association between earplugs and RR of delirium (RR, 0.56; 95% CI, 0.35–0.90; p = 0.02). The authors have disclosed that they do not have any potential conflicts of interest.