Isoflurane not at the expense of postoperative nausea and vomiting in cardiac anesthesia - an observational study

Inhalative anesthesia is of common use, but is generally known to potentiate postoperative nausea and vomiting (PONV). With an internal change of anesthesia regimen from total intravenous anesthesia (TIVA) to isoflurane (in terms of myocardial protection) in cardiac anesthesia a higher incidence of PONV was to be expected. Therefore, we evaluated the incidence of PONV after the simultaneous implementation of PONV prophylaxis.

The incidence of PONV, prospectively assessed in 197 cardiac surgery patients (68 y ± 10.4, 66.5% male) having isoflurane plus dual PONV prophylaxis with dexamethasone and droperidol, was compared with previous data of 190 controls (67 y ± 9.6, 71% male) having TIVA without and with single or dual PONV prophylaxis (n = 64 dexamethasone and droperidol, n = 25 dexamethasone, n = 101 only TIVA), and the Apfel-scoring (0-4 depending on PONV-risk). DRKS00014275. Statistics: Chi²-test, p < .05 (Bonferroni).

The incidence of PONV under isoflurane with antiemetic prophylaxis was 20.8% (95% confidence interval (CI) 15.4; 27.4) compared to 30.5% (95%CI 24; 37.6) under TIVA (p = .029; dexamethasone and droperidol 23.4% (95%CI 13.8; 35.7); dexamethasone 32% (95%CI 14.9; 53.5); only TIVA 34.7% (95%CI 25.5; 44.8)), but was not lower in high-risk patients than predicted according to Apfel-scoring 4 (71.4 vs. 78%).

In cardiac anesthesia, the use of isoflurane is not at the expense of PONV when using a risk-independent two-drug-prophylaxis. It is even beneficial resulting surprisingly in a lower incidence of PONV than under TIVA unless with and without prophylaxis. Patients with the highest risk for PONV and receiving isoflurane should receive a third antiemetic prophylactic drug.