Table 2.
Surgical and Anesthetic Characteristics of the Participants*
| Characteristic | Ketamine (N=20) | Placebo (N=20) | Overall (N=40) |
|---|---|---|---|
| ASA Physical Status Classification — no. (%)† | |||
| I | 0 (0) | 1 (5) | 1 (2.5) |
| II | 12 (60) | 15 (75) | 27 (67.5) |
| III | 8 (40) | 4 (20) | 12 (30) |
| CCI total score‡ | |||
| Mean | 2.1±2.7 | 2.7±2.6 | 2.4±2.7 |
| Median | 1 | 2.5 | 1.5 |
| Surgery department — no. (%) | |||
| General surgery | 6 (30) | 3 (15) | 9 (22.5) |
| Orthopedics, non-spine | 5 (25) | 4 (20) | 9 (22.5) |
| Otolaryngology | 2 (10) | 2 (10) | 4 (10) |
| Gynecology | 2 (10) | 3 (15) | 5 (12.5) |
| Urology | 2 (10) | 0 (0) | 2 (5) |
| Neurosurgery, non-intracranial | 1 (5) | 3 (15) | 4 (10) |
| Orthopedics, spine | 1 (5) | 2 (10) | 3 (7.5) |
| Thoracic | 1 (5) | 0 (0) | 1 (2.5) |
| Plastics | 0 (0) | 3 (15) | 3 (7.5) |
| Anesthesia type — no. (%) | |||
| General anesthesia | 19 (95) | 20 (100) | 39 (97.5) |
| Neuraxial block with sedation | 1 (5) | 0 (0) | 1 (2.5) |
| Maintenance anesthetics used — no. (%) | |||
| Nitrous oxide§ | 2 (10) | 1 (5) | 3 (7.5) |
| Propofol — no. (%) | 18 (90) | 17 (85) | 35 (87.5) |
| Sevoflurane — no. (%) | 17 (85) | 14 (70) | 31 (77.5) |
| Isoflurane — no. (%) | 1 (5) | 3 (15) | 4 (20) |
| Use of regional anesthesia — no. (%) | 1 (5) | 3 (15) | 4 (10) |
| Use of preoperative opioids — no. (%) | 9 (45) | 7 (35) | 16 (40) |
| Preoperative opioids — MME per day ¶ | |||
| Mean | 9.1±16.4 | 10.5±27.7 | 9.8±22.4 |
| Median | 0 | 0 | 0 |
| Use of intraoperative opioid infusion — no. (%) | 5 (25) | 7 (35) | 12 (30) |
| Length of surgery — min | 244±121 | 269±109 | 256±114 |
*
Plus–minus values represent means±SD.
†
American Society of Anesthesiologists (ASA) Physical Status Classification ranges from I to VI, with higher values indicating greater number and severity of pre-anesthesia medical comorbidities.
‡
Total scores on the Charlson Comorbidity Index (CCI) range from 0 to 37, with higher scores indicating greater number and severity of pre-anesthesia medical comorbidities.
§
Inhaled nitrous oxide concentration of at least 50% for at least 1 continuous hour.
¶
Milligram morphine equivalents (MME) represent potencies of opioids relative to oral morphine, with higher values indicating higher opioid doses.