0016-5107/92/3804-0418$03.00 GASTROINTESTINAL ENDOSCOPY Copyright © 1992 by the American Society for Gastrointestinal Endoscopy
Supplemental low flow oxygen prevents hypoxia during endoscopic cholangiopancreatography L. Crantock, MBBS, A. E. Cowen, MD, FRACP M. Ward, MBBS, FRCP (Edin), FRACP, R. K. Roberts, FRACP Herston, Queensland, Australia
Administration of continuous oxygen during ERCP may prevent hypoxia. Oxygen saturation was recorded using pulse oximetry in 50 consecutive patients undergoing ERCP. Patients were randomly allocated to receive no oxygen or low flow oxygen (2 liters/min) via nasal prongs or nasopharyngeal cannula. Oxygen saturation fell below 90% in 47% of patients not receiving oxygen compared with 0% in those administered oxygen (p < 0.001). No difference existed in oxygen saturations between those groups receiving supplemental oxygen via nasal prongs or nasopharyngeal cannula. Continuous administration of low flow oxygen is recommended during ERCP. (Gastrointest Endosc 1992;38:418-420)
Oxygen desaturation during endoscopic procedures is well documented l - 4 and contributes to cardiac arrhythmias, myocardial ischemia, and occasional deaths. Factors influencing desaturation include: patient's age, level of sedation, caliber of instrument used, and co-existent cardiopulmonary disease. During ERCP, patients are often older and require more sedation than those having esophago-gastro-duodenoscopy. Side-viewing duodenoscopes are usually of a larger diameter than end-viewing endoscopes, further raising the potential for hypoxemia during ERCP, and hypoxemia may often be difficult to detect clinically. Continuous low flow oxygen administered in this situation may be beneficial. We report the effect on oxygen saturation of intranasal and nasopharyngeal administered oxygen in 50 patients undergoing ERCP.
an anesthetic spray (10% lignocaine) to the back of the throat. The decision to provide supplemental oxygen was made after patients were randomly allocated to either no oxygen (group 1), oxygen via nasal prongs (group 2), or oxygen via a nasopharyngeal cannula (group 3). Oxygen flow was set at 2 liters/min. After a baseline oxygen saturation was obtained, sedation was administered intravenously and endoscopy commenced in group 1 patients. However, in group 2 and 3 patients assigned to receive oxygen, a second baseline was obtained on oxygen prior to starting endoscopy. During duodenoscopy, the lowest saturation observed was recorded. In all cases, a combination of midazolam and fentanyl was used. ERCP was carried out using either an Olympus JF IT-20 or TJF-2- or Pentax FD-34H duodenoscope. Statistical analysis was performed using Student's t-test, analysis of covariance, and the chi-square test where appropriate.
PATIENTS AND METHODS
ERCP examinations were conducted on 50 consecutive patients over a 3-month period at the Royal Brisbane Hospital. Patient ages ranged from 29 to 85 years (median, 65 years) and there were 19 men and 31 women. Pulse oximetry was performed using an OHMEDA BIOX 3700e pulse oximeter attached to the index finger. All patients underwent ERCP lying on the left side after receiving
Received December 11, 1991. Accepted January 29, 1992. From the Department of Gastroenterology, Royal Brisbane Hospital, Herston, Queensland, Australia. Reprint requests: Luke Crantock, MBBS, Department of Gastroenterology, Royal Brisbane Hospital, Herston, Queensland, Australia 4029.
418
RESULTS
Fifty patients were studied, of which 20 received no oxygen, 16 received oxygen via nasal prongs, and 15 received oxygen via nasopharyngeal cannula during ERCP. The median age of patients, sex ratio, and the incidence of cardiorespiratory disease was similar for all three groups. Sedation doses were 1.0 to 9.0 mg of midazolam (mean, 3.2 mg or 0.049 mg/kg) and 25 to 100 J.Lg of fentanyl (mean, 63 J.Lg or 0.97 J.Lg/kg). There were no significant differences in the three groups with respect GASTROINTESTINAL ENDOSCOPY
to weight or dose of midazolam/kg or fentanyl/kg (p
> 0.220 in all instances, Table 1). Mean baseline oxygen saturation prior to administration of oxygen was not significantly different across the three groups with 96.1 % ± 2.06, 95.7% ± 1.96, and 95.8% ± 2.49 in groups 1 to 3, respectively. After administration of oxygen in groups 2 and 3, but prior to endoscopy, a significant mean rise in saturation of 2.8% ± 1.38 and 2.9% ± 2.23, respectively, over baseline values was observed (p < 0.01). During ERCP, where no oxygen was given, the saturation during the procedure was significantly reduced by a mean of 6.79% ± 4.06 (p < 0.001), whereas in groups 2 and 3, where oxygen was supplied at low flow during duodenoscopy, significant increases in saturation from baseline were observed (p < 0.012) in both instances of 2.25% ± 1.81 and 1.29% ± 1.64, respectively. The distribution of oxygen saturation is shown in Table 2. The magnitude of the observed changes in oxygen saturation differed significantly between the three groups (p < 0.001) and was significantly higher during ERCP in the two groups where oxygen was supplied compared with group 1. There was no significant difference, however, in saturation during ERCP in the two groups receiving oxygen (p > 0.05). Because of low saturations «84%) during ERCP in five patients from group 1, supplemental oxygen was administered and a recovery in saturation values was subsequently observed in each case. Significant sinus tachycardia (~110 beats/min) and bradycardia «50 beats/min) were seen in eight and
two patients, respectively. One patient developed transient rapid atrial fibrillation and one required atropine for a bradycardia of 36 beats/min. There was no correlation, however, in this study between changes in heart rate and oxygen saturation. In both cases, bradycardia followed sphincterotomy. Thirty percent of ERCPs performed involved sphincterotomy or stenting. Time taken for ERCP varied from 10 to 55 min with a mean of 30.5 min. There was no significant difference in procedure time across the three groups.
DISCUSSION
ERCP is generally regarded as a safe procedure in experienced hands with a morbidity of 3% and mortality of 0.1 to 2%.5 Cardiopulmonary complications account for 50% of upper endoscopic morbidity and may be influenced by factors such as endoscope size, systemic sedation, procedure time, and patient age. 6, 7 Previous studies have identified that hypoxia during ERCP may occur in up to 44%4 of patients and that low flow supplementary oxygen may prevent desaturation. 8 We found that hypoxia (oxygen saturation
Supplemental low flow oxygen prevents hypoxia during endoscopic cholangiopancreatography L. Crantock, MBBS, A. E. Cowen, MD, FRACP M. Ward, MBBS, FRCP (Edin), FRACP, R. K. Roberts, FRACP Herston, Queensland, Australia
Administration of continuous oxygen during ERCP may prevent hypoxia. Oxygen saturation was recorded using pulse oximetry in 50 consecutive patients undergoing ERCP. Patients were randomly allocated to receive no oxygen or low flow oxygen (2 liters/min) via nasal prongs or nasopharyngeal cannula. Oxygen saturation fell below 90% in 47% of patients not receiving oxygen compared with 0% in those administered oxygen (p < 0.001). No difference existed in oxygen saturations between those groups receiving supplemental oxygen via nasal prongs or nasopharyngeal cannula. Continuous administration of low flow oxygen is recommended during ERCP. (Gastrointest Endosc 1992;38:418-420)
Oxygen desaturation during endoscopic procedures is well documented l - 4 and contributes to cardiac arrhythmias, myocardial ischemia, and occasional deaths. Factors influencing desaturation include: patient's age, level of sedation, caliber of instrument used, and co-existent cardiopulmonary disease. During ERCP, patients are often older and require more sedation than those having esophago-gastro-duodenoscopy. Side-viewing duodenoscopes are usually of a larger diameter than end-viewing endoscopes, further raising the potential for hypoxemia during ERCP, and hypoxemia may often be difficult to detect clinically. Continuous low flow oxygen administered in this situation may be beneficial. We report the effect on oxygen saturation of intranasal and nasopharyngeal administered oxygen in 50 patients undergoing ERCP.
an anesthetic spray (10% lignocaine) to the back of the throat. The decision to provide supplemental oxygen was made after patients were randomly allocated to either no oxygen (group 1), oxygen via nasal prongs (group 2), or oxygen via a nasopharyngeal cannula (group 3). Oxygen flow was set at 2 liters/min. After a baseline oxygen saturation was obtained, sedation was administered intravenously and endoscopy commenced in group 1 patients. However, in group 2 and 3 patients assigned to receive oxygen, a second baseline was obtained on oxygen prior to starting endoscopy. During duodenoscopy, the lowest saturation observed was recorded. In all cases, a combination of midazolam and fentanyl was used. ERCP was carried out using either an Olympus JF IT-20 or TJF-2- or Pentax FD-34H duodenoscope. Statistical analysis was performed using Student's t-test, analysis of covariance, and the chi-square test where appropriate.
PATIENTS AND METHODS
ERCP examinations were conducted on 50 consecutive patients over a 3-month period at the Royal Brisbane Hospital. Patient ages ranged from 29 to 85 years (median, 65 years) and there were 19 men and 31 women. Pulse oximetry was performed using an OHMEDA BIOX 3700e pulse oximeter attached to the index finger. All patients underwent ERCP lying on the left side after receiving
Received December 11, 1991. Accepted January 29, 1992. From the Department of Gastroenterology, Royal Brisbane Hospital, Herston, Queensland, Australia. Reprint requests: Luke Crantock, MBBS, Department of Gastroenterology, Royal Brisbane Hospital, Herston, Queensland, Australia 4029.
418
RESULTS
Fifty patients were studied, of which 20 received no oxygen, 16 received oxygen via nasal prongs, and 15 received oxygen via nasopharyngeal cannula during ERCP. The median age of patients, sex ratio, and the incidence of cardiorespiratory disease was similar for all three groups. Sedation doses were 1.0 to 9.0 mg of midazolam (mean, 3.2 mg or 0.049 mg/kg) and 25 to 100 J.Lg of fentanyl (mean, 63 J.Lg or 0.97 J.Lg/kg). There were no significant differences in the three groups with respect GASTROINTESTINAL ENDOSCOPY
to weight or dose of midazolam/kg or fentanyl/kg (p
> 0.220 in all instances, Table 1). Mean baseline oxygen saturation prior to administration of oxygen was not significantly different across the three groups with 96.1 % ± 2.06, 95.7% ± 1.96, and 95.8% ± 2.49 in groups 1 to 3, respectively. After administration of oxygen in groups 2 and 3, but prior to endoscopy, a significant mean rise in saturation of 2.8% ± 1.38 and 2.9% ± 2.23, respectively, over baseline values was observed (p < 0.01). During ERCP, where no oxygen was given, the saturation during the procedure was significantly reduced by a mean of 6.79% ± 4.06 (p < 0.001), whereas in groups 2 and 3, where oxygen was supplied at low flow during duodenoscopy, significant increases in saturation from baseline were observed (p < 0.012) in both instances of 2.25% ± 1.81 and 1.29% ± 1.64, respectively. The distribution of oxygen saturation is shown in Table 2. The magnitude of the observed changes in oxygen saturation differed significantly between the three groups (p < 0.001) and was significantly higher during ERCP in the two groups where oxygen was supplied compared with group 1. There was no significant difference, however, in saturation during ERCP in the two groups receiving oxygen (p > 0.05). Because of low saturations «84%) during ERCP in five patients from group 1, supplemental oxygen was administered and a recovery in saturation values was subsequently observed in each case. Significant sinus tachycardia (~110 beats/min) and bradycardia «50 beats/min) were seen in eight and
two patients, respectively. One patient developed transient rapid atrial fibrillation and one required atropine for a bradycardia of 36 beats/min. There was no correlation, however, in this study between changes in heart rate and oxygen saturation. In both cases, bradycardia followed sphincterotomy. Thirty percent of ERCPs performed involved sphincterotomy or stenting. Time taken for ERCP varied from 10 to 55 min with a mean of 30.5 min. There was no significant difference in procedure time across the three groups.
DISCUSSION
ERCP is generally regarded as a safe procedure in experienced hands with a morbidity of 3% and mortality of 0.1 to 2%.5 Cardiopulmonary complications account for 50% of upper endoscopic morbidity and may be influenced by factors such as endoscope size, systemic sedation, procedure time, and patient age. 6, 7 Previous studies have identified that hypoxia during ERCP may occur in up to 44%4 of patients and that low flow supplementary oxygen may prevent desaturation. 8 We found that hypoxia (oxygen saturation
