Use of high-flow nasal oxygenation in minimizing the occurrence of hypotension during induction of anesthesia with remimazolam in elderly patients.

Remimazolam is said to have minimum inhibitory effect on blood pressure during induction of anesthesia, but in elderly patient, hypotension may frequently occur. We assessed if avoidance of facemask ventilation (by using high-flow nasal oxygenation) after induction of anesthesia with remimazolam was associated with a low incidence of hypotension in elderly patients. With the ethics committee's approval of the study and patients' written informed consent, we studied ten patients aged ≧ 70 yr-old to obtain the incidence of hypotension (defined as the lowest mean arterial pressure of ≦ 60 mmHg) after induction of anesthesia with remimazolam (6 mg/kg/h, which was reduced to 1 mg/kg/h after the loss of consciousness), with high-flow nasal oxygenation (40 L/min, which was increased to 70 L/min after the loss of consciousness). The mean blood pressure significantly decreased after induction of anesthesia (P < 0.0001; mean decrease: 29% [95%CI 22 - 35%]), and hypotension was observed in 1 of 10 patients (10%; 95%CI 0 - 40%). None of the patients developed hypoxemia or required positive pressure ventilation via a facemask. In conclusion, avoidance of facemask ventilation (by using high-flow nasal oxygenation) after induction of anesthesia with remimazolam would be associated with a low incidence of hypotension in elderly patients.