Gastric emptying in mechanically ventilated critically ill patients: effect of neuromuscular blocking agent

To assess gastrointestinal function in critically ill patients receiving muscle relaxant and to test clinical tolerance to enteral nutrition.

Prospective study in an intensive care unit.

20 critically ill patients requiring sedation with muscle relaxant to obtain adequate mechanical ventilation.

Patients were randomly selected to receive infusions of opioid sedation during the first session (session 1) and the same sedation with muscle relaxation (cisatracurium) during the second session (session 2). Gastric emptying was assessed by the paracetamol absorption technique. Following the paracetamol absorption 200 ml enteral feed was given, and the residual gastric volume was measured 1 and 2 h after feeding. The maximum plasma concentration (Cmax) was 14 mg/l (range 5-26) when patients received sedation, and 12 mg/l (range 5-30) when they received muscle relaxant. The target time for reaching the maximum plasma concentration (Tmax) was 30 min (range 20-60) and 35 min (range 20-60), respectively, in sessions 1 and 2. There was no significant difference between the two session as regards Tmax, Cmax, or AUC(0-120). The residual volumes were 110+/-65 ml (H1) and 95+/-76 ml (H2) during session 1 and 125+/-85 ml (H1) and 105+/-90 ml (H2) during session 2.

Enteral feeding is one of the most effective methods of supporting nutritional needs in the critically ill patient. We conclude that in critically ill patients requiring sedation gastric emptying is not improved by neuromuscular blocking agent.