Abstract
Objective
Endoscopic retrograde cholangiopancreatography (ERCP) is a procedure used for diagnostic and therapeutic purposes. Most of the patients may feel pain, anxiety, and discomfort during this procedure, so conscious sedation is usually used during ERCP. General anesthesia would be considered if conscious sedation fails to achieve the requirement of the endoscopists. Several studies showed that propofol-based sedation could provide a better recovery profile. However, propofol has a narrow therapeutic window and complications may occur beyond this window. The present study aimed to find out the complications and the associated risk factors during ERCP procedure under propofol-based deep sedation.
Methods
We retrospectively reviewed data from anesthetic and procedure records of the patients who underwent ERCP under propofol-based deep sedation from January 2006 to July 2010 at Far Eastern Memorial Hospital, Taipei, Taiwan. All propofol-based deep sedations were conducted by anesthesiologists. The incidence of complications was determined and the independent risk factors identified by the multivariable logistic regression model.
Result
Propofol-based deep sedation was provided for 552 patients who received ERCP procedure. The majority of the patients were male, the mean age was 60 ± 16 years and American Society of Anesthesiologists physical status II–III. Almost 30% of patients experienced hypotension during the procedure, although no mortality or morbidity was associated with this complication. Sex, age, anesthetic time, American Society of Anesthesiologists status, hypertension, and arrhythmia were significantly different (p < 0.05) between patients with hypotension and without hypotension during the procedure. Multivariable logistic regression identified sex and age to be the independent predictors of hypotension.
Conclusion
Hypotension was the most frequent anesthetic complication during procedure under propofol-based deep sedation, but this method was safe and effective under appropriate monitoring. Age is the strongest predictor of hypotension and therefore propofol-based deep sedation should be conducted with caution in the elderly.
Keywords
age; hypotension; propofol; ERCP; deep sedation;
1. Introduction
Endoscopic retrograde cholangiopancreatography (ERCP) is a procedure used for diagnostic and therapeutic purposes such as sphincterotomy.1 Because it is a relatively uncomfortable and prolonged procedure, adequate sedation is usually beneficial for its successful completion. Sometimes, general anesthesia even may be indicated when sedation fails.2
Various sedatives, hypnotics, and narcotics have been used for ERCP.1 Several studies have shown that propofol-based sedation could provide a better recovery profile including a shorter recovery time and a higher recovery score during ERCP.3, 4, 5
Even for sedation in high-risk octogenarians, propofol has been shown to be superior to midazolam or meperidine.6 However, propofol has a narrow therapeutic window, and a small increase in dosage may cause a patient to progress from deep sedation to general anesthesia, during which hypoxemia and hypotension may occur.7 Considering these possible complications, the aim of this study was to investigate the possible predictors related to the complications of propofol-based deep sedation for ERCP.
2. Methods
After obtaining the approval from the Institutional Review Board of the Far Eastern Memorial Hospital, Taipei, Taiwan we retrospectively reviewed the anesthetic records, history charts, and procedure records of the patients who underwent ERCP under propofol-based deep sedation from January 2006 to July 2010 at the Far Eastern Memorial Hospital. The inclusion criteria included patients who received ERCP procedure under propofol-based deep sedation. In those containing multiple ERCP procedure, data were analyzed from the first time of anesthetic record. The procedure was performed with patients in the prone position. Appropriate monitoring was used for all patients including electrocardiography, pulse oximetry, noninvasive blood pressure measurements, and continuous respiratory rate measurements. Supplemental oxygen at 4 L/min was offered via nasal cannula throughout the procedure. All patients received an initial dose of 1–2.5 mg midazolam and 20–50 mg propofol. Deep sedation was further maintained with titration of continuous propofol infusion according to the guidelines of American Society of Anesthesiologists (ASA) and the depth of anesthesia was monitored by clinical observation with the modified observer's assessment of alertness/sedation score. A level of deep sedation was targeted by the anesthesiologists to adjust the rate of propofol infusion manually and boluses of propofol might be given. After the procedure, patients were sent to postanesthesia care units for observation at least 60 minutes.
Hypotension was defined by blood pressure dropping significantly to < 20% of baseline blood pressure, which was measured before sedation. Hypertension was defined by blood pressure significantly > 20% of baseline blood pressure before sedation. Desaturation was defined by oxygen saturation dropped to < 90%. If the patient developed desaturation under supplemental oxygen, the airway was opened by head-tilt/chin-lift and jaw-thrust maneuvers. Nasal airway was inserted if the above maneuvers failed. If desaturation persisted, the procedure was terminated and mask ventilation with 100% oxygen was adopted.
2.1. Statistical analysis
Statistical analysis was performed using SPSS 17.0 (SPSS Inc., Chicago, IL, USA). Interval data were expressed as mean ± standard deviation, and compared with Student ttest. Categorical data were coded and compared with Pearson Chi-square test or Fisher's exact test where appropriate. A p value of < 0.05 was regarded as significant. A multivariate logistic regression model was used to identify the independent predictors with the hypotension during propofol-based deep sedation.
3. Results
During the study period, a total of 552 patients were recruited. Baseline characteristics are shown in Table 1. The majority of the patients were male; the mean age was 60 ± 16 years (range, 14–96 years) and ASA physical status II–III. More than 200 of patients had hypertension or biliary tract infection. The number of patients with hypotension, hypertension, and desaturation during anesthesia are shown in Table 2. Almost 30% of patients experienced hypotension during the procedure.
Sex, age, anesthetic time, ASA status, hypertension, and arrhythmia were significantly different (p < 0.05) between patients with hypotension and without hypotension during the procedure. Body mass index and other comorbidities such as diabetes mellitus and biliary tract infection showed no statistical difference between the two groups (Table 3). Multivariate logistic regression identified sex and age as significantly associated with hypotension (p < 0.05; Table 4). However, when age was excluded from analysis, hypertension and anesthetic time were identified as a significant predictor (p = 0.002 and p = 0.03, respectively), while sex remained a significant independent predictor (p = 0.038).
4. Discussion
Propofol-based deep sedation can cause some complications during ERCP procedures. Results of this retrospective study showed that hypotension was the most frequent anesthetic complication during propofol-based deep sedation for ERCP, the incidence of which was 29.9%. Our rate was higher than the series reported by Amornyotin et al8 (8.8%), Kongkam et al3 (19.4%), and Vargo et al5(15.8%), which might be due to the older age of patients and the longer anesthetic time in our study. Indeed, in this study, the incidence of hypotension in the elderly is relatively high (33.3%).9 Although hypotension was found during this procedure, there was no sequela after the procedure.
Multivariable logistic regression identified sex and age were independent predictor. In our study, we found that age is positively correlated with hypertension and anesthetic time (Table 5). In addition, clinical studies imply that increasing in blood pressure is age related.10, 11, 12 Therefore, hypertension and anesthetic time were identified as a significant predictor when age was excluded from analysis. We found that age, hypertension, sex, and anesthetic time are predictors of hypotension during ERCP procedure under propofol-based sedation in this study.
The incidence of desaturation in this study was 0.18%, which was lower than the other studies.3, 4, 5, 6, 13 Only one patient with arterial oxygen saturation of 90% was observed in our study, and the patient recovered immediately after chin-lift and jaw-thrust. In our study, 100% O2 at 4 L/min via nasal cannula was offered throughout the whole procedure for preoxygenation and supplemental oxygen, so fewer decrease in SpO2 during the procedure was expected. Wang et al14 found supplementary oxygen with nasal cannula at 4 L/min in sedated patients reduced desaturation and hypoxia. Moreover, supplemental oxygen plays a significant role for a safer sedation; however, it may decrease the chance to detect early desaturation.5Due to many factors that can cause desaturation of oxygen during apnea,1, 15 preoxygenation is important that deep breathing of 100% O2 can against hypoxia after induction of anesthesia.16, 17 Thus, preoxygenation and supplemental oxygen should be advocated during ERCP.
Pulse oximetry provides an indirect measurement of the respiratory function during gastrointestinal endoscopy, but detection of abnormal ventilator activity can be delayed, especially if supplemental oxygen is provided.18Capnography is a simple and inexpensive device, but it was not used in our study. Capnography provides a continuous graphic record of respiratory movement and is more reliable than pulse oximetry in the early detection of respiratory depression during colonoscopy with sedation.18Friedrich-Rust et al19 found that capnography monitoring can reduce the incidence of hypoxemia during propofol-based sedation for colonoscopy. Therefore, capnography can be considered another advance monitor during ERCP.
Target-controlled infusion (TCI) of propofol is an alternative sedation during ERCP. Several studies have reported that TCI provides safe and effective sedation during ERCP.20, 21 Chiang et al22 found that TCI of propofol combined with opioids was associated with better hemodynamic and respiratory stability than manually controlled infusion of propofol. In the setting of propofol administered by TCI combined with bispectral index, it is possible to maintain stable sedation during endoscopic procedure, but some complications were still found during sedation.23
In our study, propofol-based deep sedation was provided during the procedure. Hypotension and respiratory depression are the most common adverse effects observed during propofol continuous infusion.3, 4 The major complication observed with the use of intravenous propofol is transient oxygen desaturation during induction, and the mid-procedural period.13 Furthermore, concomitant use of propofol with narcotics amplifies the respiratory depressant effects.24 However, Lee et al9 found that there was no static significant in the cardiopulmonary complication rates in the group given propofol combined with midazolam and fentanyl compared with propofol monosedation, and patients who received fentanyl had less minor pain.25Alfentanil and propofol were prescribed during this study, which was safe with careful monitoring.
4.1. Limitations
Some inaccurate and incomplete records were encountered.
In conclusion, hypotension was the most frequent anesthetic complication during the procedure under propofol-based deep sedation, but this method was safe and effective with appropriate monitoring. Age is the strongest predictor of hypotension and therefore propofol-based deep sedation should be conducted with caution in the elderly.