GASTRIC-EMPTYING FOLLOWING BRAIN INJURY - EFFECTS OF CHOICE OF SEDATION AND INTRACRANIAL-PRESSURE

Objective: To compare the effects of opioid and nonopioid sedation on gastric emptying. Design: Prospective, randomized trial. Setting: University teaching hospital ICU. Patients: 21 brain injured patients requiring sedation, mechanical ventilation and intracranial pressure (ICP) monitoring for >24 h. Interventions: Patients were randomized to receive infusions of either morphine plus midazolam (M), or propofol (P). Gastric emptying was assessed by the paracetamol absorption technique and by residual volumes following a 200 ml test feed. Measurements and results: Pre-sedation Glasgow Coma Score, mean ICP and the presence of bowel sounds were noted. Plasma concentrations of paracetamol were measured over 3 h following a 1 g gastric dose. There were no differences in median peak paracetamol concentration (M, 18.5 versus P, 20.8 mg/l), median time to peak concentration (M, 20 versus P, 25 min), median area under the concentration-time curve (AUG), or in the median residual volumes at 1 h (M, 14 versus P, 10.5 ml) and 2 h (M, 5 versus P, 3 ml). In patients with ICP >20 mmHg, paracetamol concentrations were lower (p < 0.05), and AUC after 30 min was lower (165 mg . min/l versus 411 mg . min/l, p = 0.023). Mean ICP was correlated with AUC (Kendall rank p = 0.027). Gastric emptying did not correlate with initial Glasgow Coma Score or presence of bowel sounds. Conclusions: Gastric emptying is not improved in patients with brain injury by avoiding morphine (1-8 mg/h) in the sedative regimen. Intracranial hypertension is associated with reduced gastric emptying.