Critical hypertension in trauma patients following prehospital emergency anaesthesia: a multi-centre retrospective observational study

Abstract

Background: Critical hypertension in major trauma patients is associated with increased mortality. Prehospital emergency anaesthesia (PHEA) is performed for 10% of the most seriously injured patients. Optimising oxygenation, ventilation, and cerebral perfusion, whilst avoiding extreme haemodynamic fluctuations are the cornerstones of reducing secondary brain injury. The aim of this study was to report the differential determinants of post-PHEA critical hypertension in a large regional dataset of trauma patients across three Helicopter Emergency Medical Service (HEMS) organisations.

Methods: A multi-centre retrospective observational study of consecutive adult trauma patients undergoing PHEA across three HEMS in the United Kingdom; 2015-2022. Critical hypertension was defined as a new systolic blood pressure (SBP) > 180mmHg within 10 min of induction of anaesthesia, or > 10% increase if the baseline SBP was > 180mmHg prior to induction. Purposeful logistical regression was used to explore variables associated with post-PHEA critical hypertension in a multivariable model. Data are reported as number (percentage), and odds ratio (OR) with 95% confidence interval (95%CI).

Results: 30,744 patients were attended by HEMS during the study period; 2161 received PHEA and 1355 patients were included in the final analysis. 161 (11.9%) patients had one or more new episode(s) of critical hypertension ≤ 10 min post-PHEA. Increasing age (compared with 16-34 years): 35-54 years (OR 1.76, 95%CI 1.03-3.06); 55-74 years (OR 2.00, 95%CI 1.19-3.44); ≥75 years (OR 2.38, 95%CI 1.31-4.35), pre-PHEA Glasgow Coma Scale (GCS) motor score four (OR 2.17, 95%CI 1.19-4.01) and five (OR 2.82, 95%CI 1.60-7.09), patients with a pre-PHEA SBP > 140mmHg (OR 6.72, 95%CI 4.38-10.54), and more than one intubation attempt (OR 1.75, 95%CI 1.01-2.96) were associated with post-PHEA critical hypertension.

Conclusion: Delivery of PHEA to seriously injured trauma patients risks haemodynamic fluctuation. In adult trauma patients undergoing PHEA, 11.9% of patients experienced post-PHEA critical hypertension. Increasing age, pre-PHEA GCS motor score four and five, patients with a pre-PHEA SBP > 140mmHg, and more than intubation attempt were independently associated with post-PHEA critical hypertension.

Keywords: Air ambulance; Anaesthesia; Blood pressure; Helicopter emergency medical service; Hypertension; Hypotension; Prehospital; Prehospital emergency care; Rapid sequence induction; Trauma.

Fig. 1

Study flow diagram of adult trauma patients who underwent PHEA in the East of England (2015–2022). Cases excluded on interrogation based on mechanism of injury with n = < 10 are grouped to ‘Other’ to protect patient confidentiality and include: smoke inhalation, asphyxiation, electrocution and hypothermia. ‘Training case’ refers to a fictional patient record that was created for the purpose of training and education. PHEA prehospital emergency anaesthesia, SBP systolic blood pressure

Fig. 2

Point estimate chart showing the proportion of adult trauma patients who underwent PHEA in the East of England (2015–2022) with a new episode of critical hypertension (defined as a new SBP > 180 mmHg ≤ 10 min of induction, or a > 10% increase if SBP was > 180 mmHg pre-PHEA) at two-minute epochs within the first ten minutes following induction. PHEA prehospital emergency anaesthesia, SBP systolic blood pressure

Fig. 3

Point estimate chart showing the prevalence (cases at point in time) of critical hypertension (defined as a new SBP > 180 mmHg ≤ 10 min of induction, or a > 10% increase if SBP was > 180 mmHg pre-PHEA) at two-minute epochs within the first ten minutes following induction, in adult trauma patients who underwent PHEA in the East of England (2015–2022). PHEA prehospital emergency anaesthesia, SBP systolic blood pressure