TABLE 1.
Baseline characteristics for all patients and subgroup of patients at high risk for postoperative nausea and vomiting, defined by pre-operative Apfel-score of 3 or 4.
| All patients (n = 385) | Patients at high risk for PONV1 (n = 180) | |||||
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| Intervention group (n = 191) | Control group (n = 194) | p | Intervention group (n = 87) | Control group (n = 93) | p | |
| Age (years), median (IQR) | 52 (43–62) | 54 (46–62) | 0.241 | 52 (43–62) | 53 (46–61) | 0.708 |
| Female sex, n (%) | 115 (60.2) | 110 (56.7) | 0.484 | 73 (83.9) | 71 (76.3) | 0.205 |
| Pre-operative score results, median (IQR) | ||||||
| Apfel score2 | 2 (2–3) | 2 (2–3) | 0.688 | 3 (3–3) | 3 (3–3) | 0.683 |
| HGSHS-53 | 1 (0–3) | 1 (0–3) | 0.798 | 2 (0–4) | 1 (0–3) | 0.483 |
| STAI-S4 | 41 (33–51) | 40 (33–50) | 0.478 | 43 (33–52) | 44 (34–53) | 0.937 |
| NRS5 | 0 (0–1) | 0 (0–2) | 0.308 | 0 (0–0) | 0 (0–0) | 0.396 |
| Type of surgery, n (%) | ||||||
| Intra-abdominal6 | 61 (31.9) | 77 (39.7) | 0.489 | 20 (23.0) | 32 (34.4) | 0.040 |
| Thyroid gland | 36 (18.8) | 30 (15.5) | 24 (27.6) | 16 (17.2) | ||
| Gynecological7 | 24 (12.6) | 15 (17.7) | 21 (24.1) | 11 (11.8) | ||
| Urogenital8 | 21 (11.0) | 26 (13.4) | 5 (5.7) | 12 (12.9) | ||
| Other9 | 49 (25.7) | 46 (13.7) | 17 (19.6) | 22 (23.7) | ||
| Duration of surgery (min), median (IQR) | 95 (69–140) | 106 (74–141) | 0.144 | 91 (68–128) | 113 (74–135) | 0.113 |
| Intra-operative drug use | ||||||
| Fentanyl (mg)10, median (IQR) | 0.5 (0.4–0.5) | 0.5 (0.5–0.6) | 0.148 | 0.5 (0.4–0.5) | 0.5 (0.4–0.6) | 0.210 |
| Sufentanil (μg)11, median (IQR) | 50 (40–64) | 50 (40–70) | 0.232 | 50 (39–60) | 50 (40–62) | 0.494 |
| PONV prophylaxis12, n (%) | 94 (49.2) | 99 (51.0) | 0.722 | 55 (63.2) | 61 (65.6) | 0.740 |
1High risk for postoperative nausea and vomiting (PONV) is defined by a pre-operative Apfel score of 3 or 4 points. 2Apfel score: Apfel score of risk for postoperative nausea and vomiting (0–4). 3HGSHS-5: 5-item version of Harvard Group Scale for Hypnotic Susceptibility (0–5). 4STAI-S: State Trait Anxiety Inventory Scale (20–80). 5NRS: numeric rating scale of pain (0–10). 6Inter alia gastric surgery, colorectal surgery, hepatic surgery, cholecystectomy.7Inter alia hysterectomy, ovariectomy, pelvic floor repair.8Inter alia prostatectomy, bladder surgery. 9Inter alia herniated intervertebral disc, lumbar spinal stenosis, adrenalectomy, plastic/reconstructive surgery. 10n = 85/93 (intervention/control group) for all patients and n = 47/50 (intervention/control group) for patients at risk for PONV. 11n = 106/101 (intervention/control group) for all patients and n = 40/43 (intervention/control group) for patients at risk for PONV. 12Intraoperative, preventive medication against postoperative nausea and vomiting (PONV) with ondansetron, dexamethasone, droperidol, metoclopramide, dimenhydrinate, or a combination according to local protocols of each study site. The following missing data were excluded from the analysis: 109/67 cases missing (all patients/patients at risk for PONV) for preoperative HGSHS-5 score.