The association of ketamine induction with blood pressure changes in paramedic rapid sequence intubation of out-of-hospital traumatic brain injury

Ketamine Use in the Intubation of Critically Ill Children with Neurological Indications: A Multicenter Retrospective Analysis

BACKGROUND

Ketamine has traditionally been avoided for tracheal intubations (TIs) in patients with acute neurological conditions. We evaluate its current usage pattern in these patients and any associated adverse events.

METHODS

We conducted a retrospective observational cohort study of critically ill children undergoing TI for neurological indications in 53 international pediatric intensive care units and emergency departments. We screened all intubations from 2014 to 2020 entered into the multicenter National Emergency Airway Registry for Children (NEAR4KIDS) registry database. Patients were included if they were under the age of 18 years and underwent TI for a primary neurological indication. Usage patterns and reported periprocedural composite adverse outcomes (hypoxemia < 80%, hypotension/hypertension, cardiac arrest, and dysrhythmia) were noted.

RESULTS

Of 21,562 TIs, 2,073 (9.6%) were performed for a primary neurological indication, including 190 for traumatic brain injury/trauma. Patients received ketamine in 495 TIs (23.9%), which increased from 10% in 2014 to 41% in 2020 (p < 0.001). Ketamine use was associated with a coindication of respiratory failure, difficult airway history, and use of vagolytic agents, apneic oxygenation, and video laryngoscopy. Composite adverse outcomes were reported in 289 (13.9%) Tis and were more common in the ketamine group (17.0% vs. 13.0%, p = 0.026). After adjusting for location, patient age and codiagnoses, the presence of respiratory failure and shock, difficult airway history, provider demographics, intubating device, and the use of apneic oxygenation, vagolytic agents, and neuromuscular blockade, ketamine use was not significantly associated with increased composite adverse outcomes (adjusted odds ratio 1.34, 95% confidence interval CI 0.99-1.81, p = 0.057). This paucity of association remained even when only neurotrauma intubations were considered (10.6% vs. 7.7%, p = 0.528).

CONCLUSIONS

This retrospective cohort study did not demonstrate an association between procedural ketamine use and increased risk of peri-intubation hypoxemia and hemodynamic instability in patients intubated for neurological indications.

Temporal changes in blood pressure following prehospital rapid sequence intubation

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.