Table 3.
Effects of air insufflation vs CO2
| Primary outcomes | Air insufflation (n = 38) |
CO2 insufflation (n = 36) |
p value* |
|---|---|---|---|
| Mean abdominal pain scores (SD) | |||
| Prior to procedure | 10.5 (21.0) | 12.8 (19.6) | 0.63 |
| 1-hr post procedure | 10.8 (19.3) | 16.4 (25.2) | 0.29 |
| 3-hr post (nAir = 34; nCO2 = 32) | 22.3 (27.8) | 20.8 (32.2) | 0.95 |
| 6-hr post (nAir = 34; nCO2 = 32) | 19.5 (26.7) | 18.3 (25.4) | 0.85 |
| 24-hr post (nAir = 34; nCO2 = 32) | 15.5 (24.0) | 15.0 (24.7) | 0.94 |
| Mean abdominal girth (cm) (SD) | |||
| Pre-procedure | 105.5 (16.6) | 101.5 (15.1) | 0.28 |
| Post-procedure (nA = 36; nB = 36) | 106.2 (17.4) | 102.2 (14.7) | 0.30 |
| Change in abdominal girth (cm) | 0.8 (4.8) | 0.7 (3.8) | 0.96 |
|
| |||
| Secondary outcomes | |||
|
| |||
| CO2 safety data (levels in mmHg) | |||
| Mean baseline CO2 level (SD) | 40.5 (6.2) | 40.3 (4.6) | 0.89 |
| Mean CO2 level (SD) | 46.1 (8.8) | 45.2 (5.7) | 0.61 |
| Maximum CO2 level (mean (SD)) | 50.0 (11.8) | 48.7 (6.4) | 0.56 |
| Mean change in CO2 level (SD) | 9.4 (10.1) | 8.8 (4.8) | 0.60 |
| Mean fentanyl dose (mcg) (SD) | 162.2 (58.6) | 155.6 (66.8) | 0.65 |
| Mean midazolam dose (mg) (SD) | 10.7 (4.5) | 9.1 (3.1) | 0.08 |
| Promethazine used (n, %) | 6 (16) | 6 (17) | 0.92 |
| Mean promethazine dose (mg) (SD) | 25.0 (0) | 17.0 (6.2) | 0.01 |
| Glucagon used (n, %) | 22 (58) | 24 (67) | 0.44 |
| Mean glucagon dose (mg) (SD) | 0.3 (0.2) | 0.5 (0.3) | 0.003 |
| Mean cannulation time (mins) (SD) | 4.3 (3.9) | 8.1 (10.4) | 0.05 |
| Cannulation success rate (n, %) | 36 (95) | 33 (92) | 0.60 |
| Mean total procedure time (mins) (SD) | 35.1 (18.7) | 39.3 (20.2) | 0.35 |
| Mean recovery discharge time (mins) (SD) | 78.8 (37.9) | 67.4 (19.7) | 0.12 |
| Mean procedure cost (dollars) (SD) | 7000 (2560) | 7170 (2200) | 0.76 |
| Mean equipment costs | 2000 (1390) | 1860 (1340) | 0.67 |
| Mean radiology costs | 94 (42) | 96 (36) | 0.83 |
| Mean hospital costs | 2420 (550) | 2570 (320) | 0.14 |
| Mean physician costs | 2490 (1350) | 2630 (1070) | 0.63 |
| Complications (n, %)† | |||
| Patients with any complication | 13 (34) | 5 (14) | 0.04†† |
| Respiratory depression | 2 (5) | 0 (0) | 0.16 |
| CO2 retention (max level > 45) | 22 (58) | 25 (69) | 0.30 |
| CO2 retention (max level > 50) | 18 (47) | 15 (42) | 0.62 |
| CO2 retention (max level > 55)‡ | 8 (22) | 5 (15) | 0.49 |
| Hypotension | 0 (0) | 0 (0) | -- |
| Cardiac arrhythmia (brady to 52)# | 1 (3) | 0 (0) | 0.33 |
| Immediate bleeding | 0 (0) | 0 (0) | -- |
| Delayed bleeding | 0 (0) | 0 (0) | -- |
| Cholangitis | 0 (0) | 0 (0) | -- |
| Pancreatitis | 2 (5) | 1 (3) | 0.57 |
| Perforation | 0 (0) | 0 (0) | -- |
| Death | 0 (0) | 0 (0) | -- |
| Other** | 3 (8) | 0 (0) | 0.08 |
By t-test for continuous variables and Chi-square (or Fisher's exact test) for categorical variables.
Complications total more than 13 because several patients have more than one event.
Only CO2 > 55 was considered a complication.
The arrhythmia was bradycardia to a nadir of 52 beats per minute; no atropine administered.
Other complications include: one patient fell in recovery and bumped head but had no injury; one patient had a post-procedure fever, was admitted and observed for 24 hours, but had no localizing infection and the fever resolved; and one patient had post-procedure abdominal pain, was admitted and observed for 24 hours, but had no structural cause of the pain, which subsequently resolved.
P-value for a single test of hypothesis; however, correction for multiple testing removes this nominal statistical significance