Is Two Better Than Three? A Systematic Review of Two-bag Intravenous N-acetylcysteine Regimens for Acetaminophen Poisoning.

Introduction: Acetaminophen poisoning is commonly treated by emergency physicians. First-line therapy is N-acetylcysteine (NAC), traditionally administered intravenously via a US Food and Drug Administration (FDA)-approved three-bag protocol in which each bag has a unique concentration and infusion duration. Recently, simplified, off-label two-bag NAC infusion protocols have become more common. The purpose of this review is to summarize the effectiveness and safety of two-bag NAC. Methods: We undertook a comprehensive search of PubMed, EMBASE, and MEDLINE from inception to December 13, 2022, for articles describing human acetaminophen poisonings treated with two-bag NAC, defined as any regimen involving two discrete infusions in two separate bags. Outcomes included effectiveness (measured by incidence of liver injury); incidence of non-allergic anaphylactoid reactions (NAAR); gastrointestinal, cutaneous, and systemic reactions; treatments for NAARs; incidence of NAC-related medication errors; and delays or interruptions in NAC administration. Results: Twelve articles met final inclusion, 10 of which compared two-bag NAC to the three-bag regimen. Nine articles evaluated the two-bag/20-hour regimen, a simplified version of the FDA-approved three-bag regimen in which the traditional first and second bags are combined into a single four-hour infusion. Nine articles assessed comparative effectiveness of two-bag NAC in terms of liver injury, most commonly assessed for by incidence of hepatotoxicity (aspartate aminotransferase or alanine aminotransferase >1,000 international units per liter). No difference in liver injury was observed between two-bag and three-bag regimens. Of nine articles comparing incidence of NAARs, eight demonstrated statistically fewer NAARs with two-bag regimens, and one showed no difference. In seven articles evaluating treatment for NAARs (antihistamines, corticosteroids, epinephrine), all showed that patients received fewer medications for NAARs with two-bag NAC. Three articles evaluated NAC-related medication errors; two demonstrated no difference, while one study evaluating only children showed fewer errors with two-bag NAC. Two studies evaluated delays and/or interruptions in NAC infusions; both favored two-bag NAC. Conclusion: For patients with acetaminophen poisoning, two-bag NAC regimens appear to have similar outcomes to the traditional three-bag regimen in terms of liver injury. Two-bag NAC regimens are associated with fewer adverse events and fewer treatments for those events than the three-bag regimen and fewer interruptions in antidotal therapy.

Ketamine Infusion for Sedation and Analgesia during Mechanical Ventilation in the ICU: A Multicenter Evaluation.

Methods: We reviewed the electronic medical record of critically ill adults who received a continuous infusion of ketamine for ≥24 hours during invasive mechanical ventilation in three hospitals over a two-year period. We captured data including ketamine indication, dose, unintended effects, and adjustments to coadministered sedatives or opioids. We analyzed these data to determine the incidence of reported unintended effects of ketamine infusion (primary outcome) and changes in exposure to coadministered sedatives or opioids during ketamine use (secondary outcome). Results: 95 mechanically ventilated adults received a ketamine infusion for a median duration of 75 hours (interquartile range [IQR] 44-115) at a mean ± standard deviation (SD) infusion rate of 1.3 ± 0.5 mg/kg/hour for the first 24 hours. At least one unintended effect attributed to ketamine was documented in 24% of cases, most frequently tachycardia (6%) and sialorrhea (6%). Other sedative or opioid infusions were administered with ketamine in 76% and 92% of cases, respectively. Comparing the total amount of sedative or opioid administered in the 24 hours prior to ketamine infusion with the total amount administered during the first 24 hours on ketamine, there were no significant differences in propofol, midazolam, or dexmedetomidine exposure, but the average fentanyl exposure was higher after ketamine (2740 ± 1812 mcg) than before (1975 ± 1860 mcg) (absolute difference 766 mcg, 95% confidence interval [CI] 442 to 1089 mcg). Conclusions: In this multicenter cohort of critically ill, mechanically ventilated adults, ketamine infusion was primarily used as an adjunct to conventional sedative and opioid infusions, with noticeable but unintended effects potentially related to ketamine in nearly one-quarter of cases.

Vasodilation in patients with calcium channel blocker poisoning treated with high-dose insulin: a comparison of amlodipine versus non-dihydropyridines.

Background: High dose insulin (HDI), an inotrope and vasodilator, is a standard therapy for calcium channel blocker (CCB) poisoning. HDI causes vasodilation by stimulating endothelial nitric oxide synthase (eNOS). Most literature supporting HDI for CCB poisoning involves verapamil toxicity; however, amlodipine now causes more CCB poisonings. Unlike other CCBs, amlodipine stimulates eNOS and may cause synergistic vasodilation with HDI. The purpose of this study was to determine if amlodipine-poisoned patients treated with HDI had more evidence of vasodilation than similarly treated patients with non-dihydropyridine (non-DHP) poisoning.Methods: This was a retrospective study from a single poison center. Cases were identified via the generic code "Calcium Antagonists" in which the therapy "High Dose Insulin/Glucose" was "performed, whether or not recommended" from 2019-2021. Evidence of vasodilation was assessed via maximum number of vasopressor infusions per case, vasopressor doses, and use of rescue methylene blue to treat refractory vasoplegia.Results: Thirty-three patients were enrolled: 18 poisoned with amlodipine, 15 with non-DHPs (verapamil n = 10, diltiazem n = 5). The median number of maximum concomitant vasopressors in the amlodipine group was 3 (IQR: 2-5; range 0-6) and 2 in the non-DHP group (IQR: 1-3; range 0-5; p = 0.04); median difference in maximum concomitant vasopressors between groups was 1 (95% confidence interval: 0-2). Median maximum epinephrine dosing was higher in the amlodipine group (0.31 mcg/kg/min) compared to non-DHPs (0.09 mcg/kg/min; p = 0.03). Use of rescue methylene blue was more common in the amlodipine group (7/18 [39%]) than in the non-DHP group (0; p = 0.009).Conclusions: Amlodipine poisoned patients treated with HDI required more vasopressors, higher doses of epinephrine, and more often received rescue methylene blue than similarly treated patients with verapamil or diltiazem poisoning. These differences suggest amlodipine-poisoned patients had more evidence of vasodilation. Further study is warranted to determine if synergistic vasodilation occurs when HDI is used to treat amlodipine poisoning.