Monitoring during sedation for endoscopy

Unsedated small-caliber esophagogastroduodenoscopy (EGD): less expensive and less time-consuming than conventional EGD

BACKGROUND

A significant portion of the costs and complications of esophagogastroduodenoscopy (EGD) are related to the use of sedation. The feasibility and tolerability of small-caliber EGD (scEGD) without sedation has been evaluated; however, there is limited data concerning times and costs associated with this procedure as compared with conventional EGD (cEGD) with sedation.

STUDY

Sixteen patients underwent scEGD with the Pentax EG-1840 (outside diameter, 6 mm) without sedation. A control group of 16 patients was matched for age, sex, day, and indication of procedure. The time of procedure, time in procedure room, time in recovery room, and procedure costs were determined in both the study and control groups. After the procedure, scEGD patients completed surveys consisting of visual-analogue scales to assess tolerance and preference regarding sedation for future procedures.

RESULTS

Procedure time, procedure room time, and recovery room time was 5.2, 16.3, and 9 minutes for scEGD and 13.5, 34.9, and 41.3 minutes for cEGD, respectively (p < 0.001 for all comparisons). The mean cost of scEGD, excluding physician fees, was $462.00, which was significantly lower than the $587.00 for cEGD (p < 0.001). Survey results revealed good tolerance for the unsedated procedure.

CONCLUSIONS

Unsedated scEGD was well tolerated and resulted in a shorter time of procedure, less time spent in procedure room, reduced recovery room time, and lower costs as compared with cEGD with sedation.

Pharmacoeconomic evaluation of flumazenil for routine outpatient EGD

BACKGROUND

Flumazenil is a benzodiazepine antagonist indicated for reversal of the sedative effects of benzodiazepines. Previous studies suggest that flumazenil may shorten recovery time after endoscopy, but there are few data on actual recovery room times and charges.

METHODS

Fifty patients undergoing routine upper endoscopy were sedated with midazolam alone in the usual titrated manner. Patients were randomized in a double-blind fashion to receive either flumazenil or saline immediately after procedure. Assessments of responsiveness, speech, facial expression, and ptosis (Observer's Assessment of Alertness/Sedation [OAA/S] scale) were made before procedure, immediately after procedure and every 15 minutes thereafter. The patient was discharged from the recovery room when vital signs and OAA/S scale reached preprocedure levels. Recovery room times and charges were recorded.

RESULTS

The flumazenil group demonstrated shorter recovery room times and recovery room charges than the placebo group (p < 0.001). The difference in recovery room charges was not statistically different when flumazenil charges were included (p = 0.09).

CONCLUSIONS

The routine use of flumazenil after midazolam sedation for upper endoscopy significantly shortened recovery time and charges but did not statistically reduce overall charges.

The effects of flumazenil on alertness and hypoxia in elderly patients after ERCP

It is not known whether hypoxia, associated with upper gastrointestinal endoscopic procedures when midazolam sedation is used without narcotics, persists into the post-procedure recovery period. Thirty consecutive patients aged over 60 years, undergoing ERCP using midazolam sedation alone, were monitored clinically and by pulse oximetry before, during and for 2 hours after the procedure. They were randomized prospectively to receive either 0.5 mg flumazenil or normal saline on extubation. Results show that patients were most hypoxic in the first 30 minutes after the procedure and that mean oxygen saturation had not returned to pre-sedation values by 2 hours. Treatment with flumazenil increased alertness 2 minutes after the procedure, and was associated with a significantly higher arterial oxygen saturation at 15 minutes.

Does nasal oxygen reduce the cardiorespiratory problems experienced by elderly patients undergoing endoscopic retrograde cholangiopancreatography?

Elderly patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) have an increased risk of sedation related complications during the procedure. To determine whether nasal oxygen supplementation (2 l/min) reduces these risks, half of 66 patients aged over 60 undergoing ERCP using minimal midazolam sedation alone were randomised to receive nasal oxygen. The arterial oxygen saturation and pulse rate of all patients were monitored by pulse oximetry before and during the procedure. Only three patients in the oxygen supplemented group (n = 33) required any form of intervention for hypoxia compared with six in the control group (n = 33). Comparison of mean arterial oxygen saturation between the groups showed significantly higher levels in the nasal oxygen group throughout the procedure. Pulse rate comparisons showed no significant difference from control group values, both groups had short periods of significant tachycardia. We conclude that minimal sedation with midazolam alone still produces hypoxia during ERCP in a substantial number of elderly patients. Nasal oxygen supplementation increases the level of patient oxygenation and reduces the need for intervention, but does not reduce tachycardia in the elderly patient. Because hyoscine may be a significant factor contributing to the tachycardia, sparing rather than routine use of this agent is advisable.

Pattern of breathing during upper gastrointestinal endoscopy: implications for administration of supplemental oxygen

Cardiopulmonary complications account for half the deaths associated with upper gastrointestinal endoscopy. The incidence of hypoxia at the time of upper gastrointestinal endoscopy can be greatly reduced by the administration of supplemental oxygen via nasal cannulae. Using dual thermistors in the mouth and nostrils of patients undergoing upper gastrointestinal endoscopy, the present study demonstrates that most patients breathe predominantly via the oral, rather than the nasal, route following intubation of the oesophagus. The implication from the study is that, if supplemental oxygen is to be used in 'at risk' patients, it would be logical to employ an oral, rather than nasal, route of administration.

Propofol for sedation during endoscopy: assessment of a computer-controlled infusion system

Propofol can be used to provide general anesthesia or sedation. Twenty patients scheduled for upper gastrointestinal endoscopy were sedated using a computer-controlled system and endoscopy was performed by the same operator. Oxygen saturation reduced significantly (p less than 0.001) during the procedure, and remained significantly lower than baseline values at the end of the procedure. Patient assessment of sedation and anxiety using linear analogue scales showed a significant increase in sedation (p less than 0.00001) and decrease in anxiety (p less than 0.003) compared with baseline values. There were variable positive (p less than 0.001) and negative (p less than 0.002) changes in blood pressure from baseline values. Overall conditions for endoscopy were good. Computer-controlled delivery of propofol provides satisfactory sedation and conditions for upper gastrointestinal endoscopy and merits further investigation.

Monitoring and safety in endoscopy

Over 50% of the complications and 60% of the deaths associated with upper GI endoscopy are cardiopulmonary in type. Oxygen desaturation and cardiac arrhythmias at the time of endoscopy are common. Ways of trying to prevent hypoxia occurring are discussed. The most effective of these is the use of supplemental oxygen. Pulse oximeters are being used increasingly frequently by endoscopists. The way in which oximeters work is described in some depth, as are some of the potential errors that may result from their use. The author believes that, as in anaesthetic practice, pulse oximeters will be used ever more frequently by endoscopists and finally become standard equipment in all endoscopy units. The case for using continuous ECG monitoring and blood pressure measurement is briefly discussed. The ASGE have recently published their recommendations on monitoring patients undergoing GI endoscopic procedures. The BSG's own working party on safety and monitoring is in the process of finalizing its recommendations, and the final part of the chapter discusses the views of this working party and gives some insight into what its final recommendations are likely to be.

Bolus or slow titrated injection of midazolam prior to upper gastrointestinal endoscopy? Relative effect on oxygen saturation and prophylactic value of supplemental oxygen

A total of 131 patients undergoing upper gastrointestinal endoscopy were sedated with midazolam given as a bolus injection over 5 seconds. The oxygen saturation was continuously measured using a pulse oximeter. Supplemental oxygen was given via nasal cannulae at a rate of 3 litres per minute to 54 patients, while the remaining 77 patients only received oxygen if their oxygen saturation dropped below 85%. Both groups in the present series were compared with 3 previously published series of patients, in whom we had used intravenous midazolam as a slow titrated injection. Despite using on average only two-thirds of the dose of midazolam, following bolus injection the degree of oxygen desaturation during the endoscopic procedure was greater, and the ability of supplemental oxygen delivered via nasal cannulae to prevent hypoxia was less (P less than 0.01), than with a slow titrated injection.

Speed of reversal of midazolam-induced respiratory depression by flumazenil--a study in patients undergoing upper G.I. endoscopy

Intravenous midazolam was given to 17 patients coming to upper G.I. endoscopy. All patients had an ear oximeter and calibrated induction plethysmograph attached to record oxygen saturation and minute volume continuously. Midazolam induced significant depression of respiration. Following removal of the endoscope, a new base line was obtained before giving intravenous flumazenil in an attempt to reverse the sedative and ventilatory effects of midazolam. When 0.5 mg of flumazenil was given over 20 s, followed by 0.1 mg every minute, up to a total of 1.0 mg, all patients were apparently awake in under 2 min. Although the flumazenil had clearly reversed the sedative effects of midazolam, the ventilatory effects were largely uninfluenced. The implications are discussed.

Review article: premedication and intravenous sedation for upper gastrointestinal endoscopy

Upper gastrointestinal endoscopy can be performed without intravenous sedation but the evidence suggests that, in the United Kingdom and United States, most patients and endoscopists prefer that some form of premedication is given. Intravenous diazepam or midazolam are used by the majority of endoscopists. In the UK, the ratio of diazepam to midazolam users is approximately 2:1, while in the USA more endoscopists are now using midazolam. Midazolam is approximately twice as potent as diazepam but, when allowance is made for this, there is probably little or no difference in the propensity of the two drugs to produce respiratory depression. The antegrade amnesic effect of midazolam is significantly superior to that of diazepam. A benzodiazepine/narcotic combination can achieve a smoother and more rapid induction with less gagging and choking, but the incidence of adverse outcomes--particularly respiratory depression--is increased significantly. Over 50% of the deaths that are associated with upper gastrointestinal endoscopy are due to cardiopulmonary problems. Hypoxia is very common if measured using non-invasive monitoring equipment, such as a pulse oximeter. Methods of preventing oxygen desaturation and thus, by inference, most cardiac arrhythmias associated with endoscopy are discussed, as is the role of flumazenil, the new benzodiazepine antagonist.