Feasibility and Potential Cost/Benefit of Routine Isoflurane Sedation Using an Anesthetic-Conserving Device: a Prospective Observational Study

BACKGROUND: Inhaled sedation is efficient and easily controllable; in low concentrations it causes minimal changes in the patient and very little interference with hemodynamics. Awakening after inhaled sedation is quick and predictable. The major reason inhaled sedation has not become widely used in intensive care is that no commercially available administration device has been available.

METHODS: In our intensive care unit we conducted a prospective observational study to assess the feasibility, benefits, and costs of routine isoflurane sedation via the AnaConDa anesthetic-administration device. We included 15 adult patients who required > 24 hours of deep sedation. Conventional intravenous sedation (benzodiazepine and opioid) had been administered according to a sedation protocol that included a predetermined target Ramsay-scale sedation score. We then switched to inhaled isoflurane via the AnaConDa, and measured sedation efficacy, cumulative dose, and daily cost of sedation. Adverse events were prospectively defined and monitored.

RESULTS: The sedation goal was reached with isoflurane in all 15 patients (P < .01, compared to the conventional sedation protocol). Hemodynamic changes were nonsignificant, and no renal or hepatic dysfunctions were observed. The frequency of meeting the sedation goal was significantly better with isoflurane than with our usual sedation protocol. With isoflurane, awakening from sedation was always < 4 hours, despite some long-duration sedations (up to 14.5 d). The overall daily cost of the 2 sedation protocols was not different in the whole group of 15 patients, but in the subgroup of 7 patients who required a mean midazolam infusion larger than the average dose, the cost difference was very significant (€218 ± 111 vs €110 ± 19, P < .01).

CONCLUSIONS: Routine ICU isoflurane sedation with the AnaConDa is easily feasible, effective, safe, and has a relatively short awakening period. In some patients with sedation difficulties, this sedation method may significantly decrease sedation cost and enhance sedation efficacy.