Study objective Survival is significantly reduced by either hypotension or hypoxia during the out-of-hospital management of major traumatic brain injury. However, only a handful of small studies have ...investigated the influence of the combination of both hypotension and hypoxia occurring together. In patients with major traumatic brain injury, we evaluate the associations between mortality and out-of-hospital hypotension and hypoxia separately and in combination. Methods All moderate or severe traumatic brain injury cases in the preimplementation cohort of the Excellence in Prehospital Injury Care study (a statewide, before/after, controlled study of the effect of implementing the out-of-hospital traumatic brain injury treatment guidelines) from January 1, 2007, to March 31, 2014, were evaluated (exclusions: <10 years, out-of-hospital oxygen saturation ≤10%, and out-of-hospital systolic blood pressure <40 or >200 mm Hg). The relationship between mortality and hypotension (systolic blood pressure <90 mm Hg) or hypoxia (saturation <90%) was assessed with multivariable logistic regression, controlling for Injury Severity Score, head region severity, injury type (blunt versus penetrating), age, sex, race, ethnicity, payer, interhospital transfer, and trauma center. Results Among the 13,151 patients who met inclusion criteria (median age 45 years; 68.6% men), 11,545 (87.8%) had neither hypotension nor hypoxia, 604 (4.6%) had hypotension only, 790 (6.0%) had hypoxia only, and 212 (1.6%) had both hypotension and hypoxia. Mortality for the 4 study cohorts was 5.6%, 20.7%, 28.1%, and 43.9%, respectively. The crude and adjusted odds ratios for death within the cohorts, using the patients with neither hypotension nor hypoxia as the reference, were 4.4 and 2.5, 6.6 and 3.0, and 13.2 and 6.1, respectively. Evaluation for an interaction between hypotension and hypoxia revealed that the effects were additive on the log odds of death. Conclusion In this statewide analysis of major traumatic brain injury, combined out-of-hospital hypotension and hypoxia were associated with significantly increased mortality. This effect on survival persisted even after controlling for multiple potential confounders. In fact, the adjusted odds of death for patients with both hypotension and hypoxia were more than 2 times greater than for those with either hypotension or hypoxia alone. These findings seem supportive of the emphasis on aggressive prevention and treatment of hypotension and hypoxia reflected in the current emergency medical services traumatic brain injury treatment guidelines but clearly reveal the need for further study to determine their influence on outcome.
Study objective For out-of-hospital cardiac arrest, authoritative, evidence-based recommendations have been made for regionalization of postarrest care. However, system-wide implementation of these ...guidelines has not been evaluated. Our hypothesis is that statewide regionalization of postarrest interventions, combined with emergency medical services (EMS) triage bypass, is associated with improved survival and neurologic outcome. Methods This was a prospective before-after observational study comparing patients admitted to cardiac receiving centers before implementation of the interventions (“before”) versus those admitted after (“after”). In December 2007, the Arizona Department of Health Services began officially recognizing cardiac receiving centers according to commitment to provide specified postarrest care. Subsequently, the State EMS Council approved protocols allowing preferential EMS transport to these centers. Participants were adults (≥18 years) experiencing out-of-hospital cardiac arrest of presumed cardiac cause who were transported to a cardiac receiving center. Interventions included (1) implementation of postarrest care at cardiac receiving centers focusing on provision of therapeutic hypothermia and coronary angiography or percutaneous coronary interventions (catheterization/PCI); and (2) implementation of EMS bypass triage protocols. Main outcomes included discharged alive from the hospital and cerebral performance category score at discharge. Results During the study (December 1, 2007, to December 31, 2010), 31 hospitals were recognized as cardiac receiving centers statewide. Four hundred forty patients were transported to cardiac receiving centers before and 1,737 after. Provision of therapeutic hypothermia among patients with return of spontaneous circulation increased from 0% (before: 0/145; 95% confidence interval CI 0% to 2.5%) to 44.0% (after: 300/682; 95% CI 40.2, 47.8). The post return of spontaneous circulation catheterization PCI rate increased from 11.7% (17/145; 95% CI 7.0, 18.1) before to 30.7% (210/684; 95% CI 27.3, 34.3) after. All-rhythm survival increased from 8.9% (39/440) to 14.4% (250/1,734; adjusted odds ratio aOR=2.22; 95% CI 1.47 to 3.34). Survival with favorable neurologic outcome (cerebral performance category score=1 or 2) increased from 5.9% (26/439) to 8.9% (153/1,727; aOR=2.26 95% CI 1.37, 3.73). For witnessed shockable rhythms, survival increased from 21.4% (21/98) to 39.2% (115/293; aOR=2.96 95% CI 1.63, 5.38) and cerebral performance category score=1 or 2 increased from 19.4% (19/98) to 29.8% (87/292; aOR=2.12 95% CI 1.14, 3.93). Conclusion Implementation of a statewide system of cardiac receiving centers and EMS bypass was independently associated with increased overall survival and favorable neurologic outcome. In addition, these outcomes improved among patients with witnessed shockable rhythms.
Study objective Out-of-hospital hypotension has been associated with increased mortality in traumatic brain injury. The association of traumatic brain injury mortality with the depth or duration of ...out-of-hospital hypotension is unknown. We evaluated the relationship between the depth and duration of out-of-hospital hypotension and mortality in major traumatic brain injury. Methods We evaluated adults and older children with moderate or severe traumatic brain injury in the preimplementation cohort of Arizona’s statewide Excellence in Prehospital Injury Care study. We used logistic regression to determine the association between the depth-duration dose of hypotension (depth of systolic blood pressure <90 mm Hg integrated over duration minutes of hypotension) and odds of inhospital death, controlling for significant confounders. Results There were 7,521 traumatic brain injury cases included (70.6% male patients; median age 40 years interquartile range 24 to 58). Mortality was 7.8% (95% confidence interval CI 7.2% to 8.5%) among the 6,982 patients without hypotension (systolic blood pressure ≥90 mm Hg) and 33.4% (95% CI 29.4% to 37.6%) among the 539 hypotensive patients (systolic blood pressure <90 mm Hg). Mortality was higher with increased hypotension dose: 0.01 to 14.99 mm Hg-minutes 16.3%; 15 to 49.99 mm Hg-minutes 28.1%; 50 to 141.99 mm Hg-minutes 38.8%; and greater than or equal to 142 mm Hg-minutes 50.4%. Log2 (the logarithm in base 2) of hypotension dose was associated with traumatic brain injury mortality (adjusted odds ratio 1.19 95% CI 1.14 to 1.25 per 2-fold increase of dose). Conclusion In this study, the depth and duration of out-of-hospital hypotension were associated with increased traumatic brain injury mortality. Assessments linking out-of-hospital blood pressure with traumatic brain injury outcomes should consider both depth and duration of hypotension.
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