[Postoperative nausea and vomiting: cost and therapeutic algorithm. Part II: high-risk patients and late PONV].

OBJECTIVE

To evaluate in high-risk patients and in usual clinical conditions, the efficiency of treatments based on an algorithm on late (24 h) postoperative nausea and vomiting (PONV).

METHODS

Prospective and descriptive.

METHODS

The nature and efficiency of prophylactic and curative PONV treatments was evaluated 24 h after surgery under general anesthesia in patients at high risk of PONV, one and 15 month after the introduction of a clinical and therapeutic algorithm. A risk score based on the type of surgery and patients characteristics determined the prophylactic treatment: high risk = droperidol 1.25 mg + ondansetron 4 mg; moderate risk = droperidol 1.25 mg. Cost of prophylactic and curative treatment was calculated according to the exact number of vials of antiemetics used.

RESULTS

The use of the therapeutic algorithm leads to a reduction of PONV by a half (47.7% of 109 patients in 1999 vs. 24.5% of 102 patients in 2001) while twice more patients received a prophylactic treatment (32.1% vs. 75.5%). The number of patients needed to be treated (NNT) according to the algorithm to avoid PONV was 1.8 in this high-risk population. However, the relative risk to have PONV was only reduced by 66% with the combination of two antiemetics in 2001 and 22.5% patients still suffered from PONV despite the double prophylactic treatments. The relative risk of PONV without prophylactic treatment was spontaneously reduced by 25% between the two study periods (54% vs. 40%). After 15 months, the recommendations were followed in 43.1% of patients. A curative treatment was given in the same percentage of patients in 2001 and 1999 (63.4% vs. 68%), but followed the recommendations in fivefold more patients (47% vs. 9.1%). The cost of PONV treatment (prophylactic and curative) was increased by 3.5-fold between the two periods ( 55 for 109 patients vs. 190 for 102 patients).

CONCLUSIONS

The use of a PONV therapeutic algorithm based on a scored risk was associated to a lower reduction of late PONV than already published in the literature while the cost was increased as expected. This suggests the efficacy of antiemetic prophylactic treatment might have been overestimated by large multicenter trials and is less in usual clinical conditions. Thus local evaluation of practice is required by performing quality insurance programs.