Temporal changes in blood pressure following prehospital rapid sequence intubation

Rapid Sequence intubation (RSI) is an airway procedure that uses sedative and paralytic drugs to facilitate endotracheal intubation. It is known that RSI could impact blood pressure in the peri-intubation period. However, little is known about blood pressure changes in longer time frames. Therefore, this analysis aims to describe the changes in systolic blood pressure in a large cohort of paramedic-led RSI cases over the whole prehospital timespan.

Intensive Care Paramedics in Victoria, Australia, are authorised to use RSI in medical or trauma patients with a Glasgow Coma Scale <10. This retrospective cohort study analysed data from patientcare records for patients aged 12 years and above that had received RSI, from 1 January 2008 to 31 December 2019. This study quantifies the systolic blood pressure changes using regression with fractional polynomial terms. The analysis is further stratified by high versus Low Shock Index (LSI). The shock index is calculated by dividing pulse rate by systolic blood pressure.

During the study period RSI was used in 8613 patients. The median number of blood pressure measurements was 5 (IQR 3-8). Systolic blood pressure rose significantly by 3.4 mm Hg (p<0.001) and then returned to baseline in the first 5 min after intubation for LSI cases. No initial rise in blood pressure is apparent in High Shock Index (HSI) cases. Across the whole cohort, systolic blood pressure decreased by 7.1 mm Hg (95% CI 7.9 to 6.3 mm Hg; p<0.001) from the first to the last blood pressure measured.

Our study shows that in RSI patients a small transient elevation in systolic blood pressure in the immediate postintubation period is found in LSI, but this elevation is not apparent in HSI. Blood pressure decreased over the prehospital phase in RSI patients with LSI, but increased for HSI cases.