PCO2 on arrival as a predictive biomarker in patients with out-of-hospital cardiac arrest.

BACKGROUND: Treating patients with out-of-hospital cardiac arrest (OHCA) requires early prediction of outcome, ideally on hospital arrival, as it can inform the clinical decisions involved. This study evaluated whether partial pressure of carbon dioxide (PCO2) on arrival is associated with outcome at one month OHCA patients. METHODS: This was a single-center retrospective study of adult OHCA patients treated between January 2016 and December 2020. Outcomes were defined along the Cerebral Performance Category (CPC) scale. Primary outcome was mortality (CPC 5) at one month. Secondary outcomes were death or unfavorable neurological outcome (CPC 3-5) and unfavorable neurological outcome (CPC 3-4) at one month. Multivariable analysis was adjusted for age, sex, witnessed cardiac arrest, bystander cardiopulmonary resuscitation, initial shockable rhythm, and time from call to emergency medical services to hospital arrival. RESULTS: Out of 977 OHCA patients in the study period, 19 were excluded because they were aged under 18 years, 79 because they underwent extracorporeal cardiopulmonary resuscitation, and 101 due to lack of PCO2 data. This study included 778 patients total; mortality (CPC 5) at one month was observed in 706 (90.7%), death or unfavorable neurological outcome (CPC 3-5) in 743 (95.5%), and unfavorable neurological outcome (CPC 3-4) in 37 (4.8%). In multivariable analysis, high PCO2 levels showed significant association with mortality (CPC 5) at one month (odds ratio [OR] [per 5 mmHg], 1.14; 95% confidence interval [CI], 1.08-1.21), death or unfavorable neurological outcome (CPC 3-5) (OR [per 5 mmHg], 1.29; 95% CI, 1.17-1.42), and unfavorable neurological outcome (CPC 3-4) (OR [per 5 mmHg], 1.21; 95% CI, 1.04-1.41). CONCLUSIONS: High PCO2 on arrival was significantly associated with mortality and unfavorable neurological outcome in OHCA patients.

Cardiac arrest with retropharyngeal hematoma caused by minor facial injuries from a ground level fall.

Background: Traumatic retropharyngeal hematoma followed by airway obstruction is extremely rare. In this report, we show unique images from two cases of out-of-hospital cardiac arrest due to airway obstruction caused by massive retropharyngeal hematoma after a minor facial injury. Case presentation: Case 1: A 78-year-old man was transferred to our emergency department due to cardiac arrest. He presented with respiratory insufficiency after a ground level fall. His neck was swollen, and the attending physician performed an emergent cricothyroidotomy to secure his airway and administered intravenous adrenaline. Computed tomography revealed a massive retropharyngeal hematoma and severe hypoxic encephalopathy. Despite a temporary return of spontaneous circulation (ROSC), the patient died on the admission day.Case 2: A 68-year-old woman presented with dyspnea, prompting her family to call an ambulance. On the way to the hospital, the ambulance crew determined the patient was in cardiac arrest. The patient's history revealed a ground level fall in which she hit her face. Computed tomography revealed a massive retropharyngeal hematoma compressing her upper airway. Although ROSC was obtained, the patient died on the 12th day of hospitalization due to hypoxic encephalopathy.Extension views of cervical spine images identified angular instability without cervical bone fracture in both cases, suggesting that possible injuries of the anterior longitudinal ligament contributed to the retropharyngeal hematoma. Conclusions: Patients presenting with asphyxia after a simple ground level fall accompanied by minor facial injuries should be assessed by emergency physicians for the possibility of a retropharyngeal hematoma. In both cases presented here, unique images indicate possible injuries of the anterior longitudinal ligament.