Table 2.
Potential risk factors for receiving flumazenil during anesthesia recovery.a
| Characteristic | Cases (n = 131) | Controls (n = 262) | Univariable analysisb |
Multivariable analysisb |
||||
|---|---|---|---|---|---|---|---|---|
| OR | 95% CI | p | OR | 95% CI | p | |||
| Medical comorbidity or condition | ||||||||
| BMI | 28.3 (6.8) | 29.0 (7.5) | 0.93 | 0.80–1.08 | 0.37 | 0.96 | 0.92–1.01 | 0.09 |
| Lung disease | 10 (7.6) | 27 (10.3) | 0.73 | 0.35–1.53 | 0.40 | 0.77 | 0.31–1.92 | 0.57 |
| Long-term use of opioid or benzodiazepine | 40 (30.5) | 81 (30.9) | 0.98 | 0.60–1.61 | 0.93 | 0.78 | 0.41–1.48 | 0.44 |
| OSAc | 31 (23.7) | 40 (15.3) | 1.83 | 1.04–3.20 | 0.04 | 2.27 | 1.02–5.09 | 0.046 |
| ASA PS score | ||||||||
| I or II | 67 (51.1) | 153 (58.4) | 1.00 | – | – | – | – | – |
| ≥III | 64 (48.9) | 109 (41.6) | 1.48 | 0.90–2.41 | 0.12 | 1.28 | 0.68–2.41 | 0.44 |
| Anesthetic agent | ||||||||
| Volatile | 63 (48.1) | 195 (74.4) | 1.00 | – | <0.001 | – | – | <0.001 |
| TIVAd | 68 (51.9) | 67 (25.6) | 5.72 | 3.07–10.66 | – | 6.09 | 2.60–14.25 | – |
| Anesthetic duration, mine | 169 (104–296) | 171 (92–268) | 1.08 | 1.01–1.16 | 0.03 | 1.13 | 1.03–1.24 | 0.01 |
| Preoperative medication | ||||||||
| Gabapentin | 21 (16.0) | 26 (9.9) | 2.67 | 1.11–6.42 | 0.03 | 1.63 | 0.47–5.64 | 0.44 |
| Benzodiazepinef | 119 (90.8) | 160 (61.1) | 6.74 | 3.41–13.31 | <0.001 | 8.17 | 3.71–17.99 | <0.001 |
| Sustained-release opioid | 20 (15.3) | 21 (8.0) | 2.68 | 1.23–5.82 | 0.01 | 2.60 | 0.88–7.68 | 0.08 |
| Intraoperative medication | ||||||||
| Neuraxial opioid | 4 (3.1) | 13 (5.0) | 0.45 | 0.11–1.87 | 0.27 | 0.26 | 0.04–1.80 | 0.17 |
| Systemic opioid (ME), mg | 19 (5–30) | 23.3 (10–31.5) | 0.89 | 0.82–0.98 | 0.02 | 0.94 | 0.81–1.08 | 0.38 |
| Ketamineg | 31 (23.7) | 45 (17.2) | 1.57 | 0.91–2.73 | 0.11 | 1.77 | 0.85–3.71 | 0.13 |
| Nondepolarizing muscle relaxants | 64 (48.9) | 133 (50.8) | 0.86 | 0.48–1.55 | 0.62 | 1.31 | 0.56–3.07 | 0.53 |
ASA-PS, American Society of Anesthesiologist Physical Status; BMI, Body Mass Index calculated as weight in kilograms divided by height in meters squared; ME, morphine equivalents; OR, Odds Ratio; OSA, Obstructive Sleep Apnea; TIVA, Total Intravenous Anesthesia.
Continuous data are presented as mean (SD) or as median (interquartile range); categorical data as number of patients (percentage of sample).
Analyses were completed with conditional logistic regression factoring in the matched-set (1:2) study design. In addition to univariable analysis, all variables were included in the multivariable model. The odds ratio is presented for a 5 kg.m−2 increase in BMI, 30 min increase in anesthetic duration, and 5-ME increase in intraoperative systemic opioid.
Diagnosis from a documented history or a positive screen for OSA.
Secondary analysis for patients maintained with TIVA, compared to those who received inhalation agents, showed an increased frequency of receiving midazolam (number of instances), an increased median (SD) dose of midazolam (in milligrams), and a decreased median dose (interquartile range) of intraoperative systemic opioid (ME in milligrams): 110 (84.0%) vs. 169 (64.5%); 3.23 (0.24) vs. 1.65 (0.17); and 10 (5.0–15.3) vs. 25 (17.9–35.0), respectively (all p < 0.001).
Multivariate analysis with 95% confidence in units of 30 minutes.
Among patients who received midazolam, index cases received a median dose (interquartile range) of 3.5 mg (2.0–4.0 mg), and controls received 2.0 mg (2.0–2.0 mg) (p < 0.001).
Secondary analysis for patients who received ketamine showed no difference between the median perioperative dose (interquartile range) for index cases (20 mg [10–20 mg]) and controls (20 mg [10–20 mg]) (p = 0.88).