Table 1.
Characteristics of patients
| Characteristic | Val/Val | Val/Met | Met/Met | P value |
|---|---|---|---|---|
| Number of patients | 30 | 66 | 21 | – |
| Age (years) | 71 ± 11 | 69 ± 11 | 66 ± 12 | 0.45 |
| Sex (male/female; n) | 22/8 | 49/17 | 14/7 | 0.79 |
| Body mass index (kg m−2) | 27.7 ± 4.3 | 27.5 ± 4.2 | 26.6 ± 3.9 | 0.59 |
| Preoperative use of analgesics* | 6 (20%) | 11 (17%) | 2 (10%) | 0.64 |
| Type of cardiothoracic surgery [n (%)] | 0.41 | |||
| CABG | 7 (23%) | 16 (24%) | 2 (10%) | – |
| Valve surgery | 5 (17%) | 16 (24%) | 7 (33%) | – |
| CABG and valve surgery | 14 (47%) | 23 (35%) | 6 (29%) | – |
| Aortic surgery | 4 (13%) | 11 (17%) | 6 (29%) | – |
| Mean duration of anaesthesia (h) | 4.2 ± 1.2 | 4.2 ± 1.0 | 3.7 ± 1.1 | 0.24 |
| Mean intraoperative dose of fentanyl (mg) | 1.6 ± 0.5 | 1.6 ± 0.5 | 1.7 ± 0.6 | 0.68 |
| Mean intraoperative dose of remifentanil (mg) | 1.0 ± 1.0 | 1.2 ± 1.3 | 1.3 ± 1.3 | 0.71 |
| Cumulative postoperative dose of morphine (mg) before morphine bolus | 12.6 ± 6.8 | 13.6 ± 6.7 | 14.7 ± 6.6 | 0.55 |
| Morphine bolus dose 2.5 mg/7.5 mg (n)† | 14/13 | 30/33 | 15/6 | 0.16 |
| Unavoidable routine care procedure, i.e. turning/turning & drain removal | 11/19 | 36/30 | 8/13 | 0.18 |
| Mean ICU stay (days) | 2.1 ± 1.6 | 2.3 ± 2.2 | 2.4 ± 1.5 | 0.83 |
All values are expressed as means ± SD or as number (%). Abbreviations are as follows: CABG, coronary artery bypass graft; COMT, catechol-O-methyltransferase; and ICU, intensive care unit.
*
Includes paracetamol, nonsteroidal anti-inflammatory drugs and tramadol.
†
There were six missing values.