Medical conditions associated with out-of-hospital endotracheal intubation

Abstract

Background: While prior studies describe the clinical presentation of patients requiring paramedic out-of-hospital endotracheal intubation (ETI), limited data characterize the underlying medical conditions or comorbidities.

Objective: To characterize the medical conditions and comorbidities of patients receiving successful paramedic out-of-hospital ETI.

Methods: We used Pennsylvania statewide emergency medical services (EMS) clinical data, including all successful ETIs performed during 2003-2005. Using multiple imputation triple-match algorithms, we probabilistically linked EMS ETI to statewide death and hospital admission data. Each hospitalization record contained one primary and up to eight secondary diagnoses, classified according to the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). We determined the proportion of patients in each major ICD-9-CM diagnostic group and subgroup. We calculated the Charlson Comorbidity Index score for each patient. Using binomial proportions with confidence intervals (CIs), we analyzed the data and combined imputed results using Rubin's method.

Results: Across the imputed sets, we linked 25,733 (77.7% linkage) successful ETIs to death or hospital records; 56.3% patients died before and 43.7% survived to hospital admission. Of the 14,478 patients who died before hospital admission, most (92.7%; 95% CI: 92.5-93.3%) had presented to EMS in cardiac arrest. Of the 11,255 hospitalized patents, the leading primary diagnoses were circulatory diseases (32.0%; 95% CI: 30.2-33.7%), respiratory diseases (22.8%; 95% CI: 21.9-23.7%), and injury or poisoning (25.2%; 95% CI: 22.7-27.8%). Prominent primary diagnosis subgroups included asphyxia and respiratory failure (15.2%), traumatic brain injury and skull fractures (11.3%), acute myocardial infarction and ischemic heart disease (10.9%), poisonings and drug and alcohol disorders (6.7%), dysrhythmias (6.7%), hemorrhagic and nonhemorrhagic stroke (5.9%), acute heart failure and cardiomyopathies (5.6%), pneumonia and aspiration (4.9%), and sepsis, septicemia, and septic shock (3.2%). Most of the admitted ETI patients had a secondary circulatory (70.8%), respiratory (61.4%), or endocrine, nutritional, or metabolic (51.4%) secondary diagnosis. The mean Charlson Index score was 1.6 (95% CI: 1.5-1.7).

Conclusions: The majority of successful paramedic ETIs occur on patients with cardiac arrest and circulatory and respiratory conditions. Injuries, poisonings, and other conditions compromise smaller but important portions of the paramedic ETI pool. Patients undergoing ETI have multiple comorbidities. These findings may guide the systemic planning of paramedic airway management care and education.

FIGURE

Overview of medical condition classification. We classified patients dying in the field or ED as “Death Before Hospital Admission.” For patients surviving to hospital admission, we determined the primary and secondary medical conditions from the primary and secondary ICD-9-CM discharge diagnosis codes. Each hospitalized patient had one primary and up to 8 secondary diagnoses. ETI = Endotracheal Intubation. ED = Emergency Department. ICD-9-CM = International Classification of Diseases, Clinical Modification, ninth edition.