Severe neurological impairment was more prevalent in cardiac arrest survivors who were administered epinephrine than in those administered placebo in a randomized clinical trial; short-term reduction of brain tissue O₂ tension (PbtO₂) after epinephrine administration in swine following a short duration of untreated cardiac arrest has also been reported. We investigated the effects of epinephrine administered during cardiopulmonary resuscitation (CPR) on cerebral oxygenation after restoration of spontaneous circulation (ROSC) in a swine model with a clinically relevant duration of untreated cardiac arrest. After 7 min of ventricular fibrillation, 24 pigs randomly received either epinephrine or saline placebo during CPR. Parietal cortex measurements during 60-min post-resuscitation period showed that the area under the curve (AUC) for PbtO₂ was smaller in the epinephrine group than in the placebo group during the initial 10-min period and subsequent 50-min period (both p < 0.05). The AUC for number of perfused cerebral capillaries was smaller in the epinephrine group during the initial 10-min period (p = 0.005), but not during the subsequent 50-min period. In conclusion, epinephrine administered during CPR reduced PbtO₂ for longer than 10 min following ROSC in a swine model with a clinically relevant duration of untreated cardiac arrest.

Background: Hyperbaric oxygen therapy (HBOT) is the standard treatment for moderate to severe carbon monoxide (CO) poisoning, but middle ear barotrauma (MEB) remains a common complication. This study identified risk factors associated with MEB in patients undergoing monoplace HBOT. Methods: This retrospective cohort study included patients treated for CO poisoning with monoplace HBOT at a tertiary academic hospital between May 2021 and December 2023. MEB severity was assessed before and after treatment using video otoscopy and graded according to the modified O’Neill Grading System. Results: MEB occurred predominantly at lower severity grades according to the O’Neill scale. In univariate analysis, significant risk factors for MEB included altered mental status at presentation (OR: 3.16, 95% CI: 1.35–7.40, p = 0.008), serum albumin > 4.3 g/dL (OR: 0.22, 95% CI: 0.10–0.65, p = 0.004), and magnesium levels (OR: 0.21, 95% CI: 0.05–0.98, p = 0.046). Multivariate analysis confirmed altered mental status (OR: 3.16, 95% CI: 1.05–9.52, p = 0.041), albumin > 4.3 g/dL (OR: 0.26, 95% CI: 0.10–0.65, p = 0.004), and magnesium level (OR: 0.21, 95% CI: 0.05–0.88, p = 0.033) as independent predictors of MEB. Patients with higher albumin and magnesium levels showed lower risk. Conclusions: Altered mental status, lower albumin, and lower magnesium levels predicted middle ear barotrauma in patients undergoing monoplace HBOT for CO poisoning. These findings highlight the importance of careful pre-treatment evaluation and close monitoring during therapy to reduce the incidence of MEB.

We investigated the association between post-rewarming fever (PRF) and 6-month neurologic outcomes in cardiac arrest survivors. This was a multicenter study based on a registry of comatose adult (≥18 years) out-of-hospital cardiac arrest (OHCA) survivors who underwent targeted temperature management between October 2015 to December 2018. PRF was defined as peak temperature ≥ 38.0 °C within 72 h after completion of rewarming, and PRF timing was categorized as within 24, 24–48, and 48–72 h epochs. The primary outcome was neurologic outcomes at six months after cardiac arrest. Unfavorable neurologic outcome was defined as cerebral performance categories three to five. A total of 1031 patients were included, and 642 (62.3%) had unfavorable neurologic outcomes. PRF developed in 389 (37.7%) patients in 72 h after rewarming: within 24 h in 150 (38.6%), in 24–48 h in 155 (39.8%), and in 48–72 h in 84 (21.6%). PRF was associated with improved neurologic outcomes (odds ratio (OR), 0.633; 95% confidence interval (CI), 0.416–0.963). PRF within 24 h (OR, 0.355; 95% CI, 0.191–0.659), but not in 24–48 h or 48–72 h, was associated with unfavorable neurologic outcomes. Early PRF within 24 h after rewarming was associated with favorable neurologic outcomes.

Current treatment recommendations for hyperkalemic cardiac arrest focus exclusively on the addition of antihyperkalemic therapies and are otherwise identical to those for cardiac arrest caused by non-hyperkalemic etiologies. We were unable to find any studies that specifically examine the hemodynamic effects of cardiopulmonary resuscitation in hyperkalemic cardiac arrest compared to cardiac arrest from non-hyperkalemic etiologies. We hypothesized that myocardial ischemic contracture would be less severe in hyperkalemic cardiac arrest compared with ventricular fibrillation cardiac arrest, resulting in higher cerebral perfusion pressure, brain tissue oxygen tension, and coronary perfusion pressure during cardiopulmonary resuscitation. Twenty-two pigs randomly underwent either electrically induced ventricular fibrillation arrest or hyperkalemic arrest induced by potassium infusion. Hemodynamic, echocardiographic, and brain tissue oxygen tension measurements were obtained during advanced cardiovascular life support and compared using linear mixed-effects models. Two animals developed massive hemothorax associated with cardiopulmonary resuscitation and were excluded from further analysis. The remaining 20 animals had no internal organ injury due to cardiopulmonary resuscitation and were included in the study. Left ventricular wall thickness was significantly lower in the hyperkalemic arrest group than in the ventricular fibrillation arrest group (group effect, P = 0.019). The decrease in end-diastolic volume over time was significantly less pronounced in the hyperkalemic arrest group (group-time interaction, P = 0.010). Coronary perfusion pressure (group effect, P = 0.041) and cerebral perfusion pressure (group effect, P = 0.020) were significantly lower in the hyperkalemic arrest group. Although not significant, brain tissue oxygen tension was also lower in the hyperkalemic arrest group. In conclusion, the left ventricular wall thickness was smaller, and the decrease in end-diastolic volume over time was less pronounced in the hyperkalemic arrest group. However, perfusion pressure was poorer, and cerebral oxygenation was not better in the hyperkalemic arrest group.

We investigated whether achieving estimated average glucose (EAG) levels versus achieving standard glucose levels (180 mg/dL) was associated with neurologic outcome in cardiac arrest survivors. This single-center retrospective observational study included adult comatose cardiac arrest survivors undergoing therapeutic hypothermia (TH) from September 2011 to December 2017. EAG level was calculated using HbA1c obtained after the return of spontaneous circulation (ROSC), and the mean glucose level during TH was calculated. We designated patients to the EAG or standard glucose group according to whether the mean blood glucose level was closer to the EAG level or 180 mg/dL. Patients in the EAG and standard groups were propensity score- matched. The primary outcome was the 6-month neurologic outcome. The secondary outcomes were hypoglycemia (≤70 mg/dL) and serum neuron-specific enolase (NSE) at 48 h after ROSC. Of 384 included patients, 137 (35.7%) had a favorable neurologic outcome. The EAG group had a higher favorable neurologic outcome (104/248 versus 33/136), higher incidence of hypoglycemia (46/248 versus 11/136), and lower NSE level. After propensity score matching, both groups had similar favorable neurologic outcomes (24/93 versus 27/93) and NSE levels; the EAG group had a higher incidence of hypoglycemia (21/93 versus 6/93). Achieving EAG levels was associated with hypoglycemia but not neurologic outcome or serum NSE level.