Patient-controlled versus nurse-administered sedation with propofol during colonoscopy. A prospective randomized trial

Sedation in endoscopic practice

Sedation impacts every aspect of endoscopy practice--the quality fo the examination, the satisfaction of endoscopist and of patient, the efficiency and cost of delivering services, and the compliance of patients with surveillance guidelines. New sedation agents and improved patient-monitoring and drug-delivery technologies are challenging traditional practices. Increasing demand for endoscopic services, shrinking reimbursements, and competing diagnostic technologies are prompting recognition that new approaches to sedation can improve practice efficiency and patient outcome. This article discusses new developments in endoscopic sedation and their implications for practice management.

Sedation during regional anesthesia: inhalation versus intravenous

PURPOSE OF REVIEW

Sedation of patients either with or without regional anesthesia is discussed to ascertain sedation requirements in the two groups. The differences between 'monitored anesthesia care' and conscious sedation are defined. Several current and promising methods with which we can evaluate a patient's degree or level of sedation are assessed. Also noted are safety concerns regarding monitoring solutions for patients undergoing monitored anesthesia care. Well established techniques, including some which are decidedly 'low tech', are examined. Several routes of intravenous administration are discussed along with patient variables. Sevoflurane sedation is mentioned with regards to administration, advantages and drawbacks.

RECENT FINDINGS

Several modalities have been studied for evaluation of a patient's level of sedation, some of which have little applicability in the operating room. Processed electroencephalographic monitoring has tremendous promise but is currently not reliable enough to assess sedation level. Sevoflurane has a role in sedation, providing the limitations are understood. One drawback of sevoflurane is its greater degree of disinhibition when compared with intravenous agents, necessitating conversion to general anesthesia.

SUMMARY

Evaluating the degree of patient sedation is a need that technology has yet to meet. Several techniques have been tried in intensive care units but have little utility in the operating room. Utilization of processed electroencephalogram waveforms has the greatest potential but is of limited value at the present time. Sevoflurane is demonstrated to have a limited role in sedation but may prove useful in specific circumstances.

Anaesthesia and sedation for gastrointestinal endoscopy

PURPOSE OF REVIEW

Wide variations exist around the world in the practice of sedation for endoscopy, in terms of the depth of sedation, drug choices, delivery methods and the practitioners involved. These variations are driven by historical, cultural and economic factors. Professional bodies have promulgated guidelines in an attempt to unify and raise standards for sedation and monitoring. Nevertheless, preventable morbidity associated with sedation still occurs. A review of the recent literature is therefore justified.

RECENT FINDINGS

The main themes in this literature are the advent of the widespread use of propofol by non-anaesthesiologists, and particularly non-medical staff; novel methods for administering propofol; the acceptability of endoscopy without sedation; and emerging technologies that obviate the need for endoscopy.

SUMMARY

There is still much scope to research and refine sedation techniques for endoscopy. We believe that the involvement of anaesthesiologists in this research is vital.

Effect-site targeted patient-controlled sedation with propofol: comparison with anaesthetist administration for colonoscopy

Patient-controlled sedation (PCS) allows patients to match their sedation requirement to perceived discomfort. The significant delay in onset of sedation may be overcome with effect-site steered target controlled infusion, but previously only trials in volunteers have been carried out. We therefore conducted a randomised, double-blind controlled trial comparing effect-site steered propofol PCS with anaesthetist-administered propofol sedation in 40 patients presenting for colonoscopy. The initial effect-site target in the PCS group was 0.8 microg.ml(-1), increment was 0.1 microg.ml(-1) and lockout was 3 min. Patient and endoscopist satisfaction and operating conditions were similar between the two groups. PCS patients were sedated more slowly (13 [7.1] vs. 3 [1.1] min; p < 0.0001) and less deeply (minimum BIS value: 71 [16] vs. 58 [15]; p = 0.13) than anaesthetist-administered propofol sedation patients. More of the latter patients were hypotensive, but all patients had similar recollection of events during the procedure and similar quality of recovery.

Pharmacokinetic and Pharmacodynamic Characteristics of??Medications Used for Moderate Sedation

The ability to deliver safe and effective moderate sedation is crucial to the ability to perform invasive procedures. Sedative drugs should have a quick onset of action, provide rapid and clear-headed recovery, and be easy to administer and monitor. A number of drugs have been demonstrated to provide effective sedation for outpatient procedures but since each agent has its own limitations, a thorough knowledge of the available drugs is required to choose the appropriate drug, dose and/or combination regimen for individual patients. Midazolam, propofol, ketamine and sevoflurane are the most frequently used agents, and all have a quick onset of action and rapid recovery. The primary drawback of midazolam is the potential for accumulation of the drug, which can result in prolonged sedation and a hangover effect. The anaesthetics propofol and sevoflurane have recently been used for sedation in procedures of short duration. Although effective, these agents require monitored anaesthesia care. Ketamine is an effective agent, particularly in children, but there is concern regarding emergence reactions. AQUAVAN injection (fospropofol disodium), a phosphorylated prodrug of propofol, is an investigational agent possessing a unique and distinct pharmacokinetic and pharmacodynamic profile. Compared with propofol emulsion, AQUAVAN is associated with a slightly longer time to peak effect and a more prolonged pharmacodynamic effect. Advances in the delivery of sedation, including the development of new sedative agents, have the potential to further improve the provision of moderate sedation for a variety of invasive procedures.

Propofol versus traditional sedative agents for gastrointestinal endoscopy: a meta-analysis

BACKGROUND & AIMS

Even though propofol has better recovery profile than traditional agents, its use is limited because of the perception of increased complication rates. Because an adequately powered trial comparing risk of propofol with traditional agents is lacking, we performed a meta-analysis of the current literature.

METHODS

We searched Medline (1966-October 2004), EMBASE (1980-October 2004), and Cochrane controlled trials registry. The following 4 cardiopulmonary complications were assessed: hypoxia, hypotension, arrhythmias, and apnea. Procedures were divided into 3 groups: esophagogastroduodenoscopy group, colonoscopy group, and endoscopic retrograde cholangiopancreatography/endoscopic ultrasonography group. Pooled odds ratios for complications were calculated for all the procedures combined and then separately for the 3 groups. Random effects models were used for 2-proportion comparisons.

RESULTS

Of the 90 citations identified, 12 original studies qualified for this meta-analysis and included 1161 patients. Of these, 634 received propofol, and 527 received midazolam, meperidine, and/or fentanyl. Most of the included studies were randomized trials of moderate quality and nonsignificant heterogeneity (Cochran Q = 4.81, P = .90). Compared with traditional sedative agents, the pooled odds ratio with the use of propofol for developing hypoxia or hypotension for all the procedures combined was 0.74 (95% confidence interval [CI], 0.44-1.24); for EGD, 0.85 (95% CI, 0.33-2.17); for colonoscopy, 0.4 (95% CI, 0.2-0.79); and for ERCP/EUS, 1.07 (95% CI, 0.38-3.01).

CONCLUSIONS

Propofol sedation during colonoscopy appears to have lower odds of cardiopulmonary complications compared with traditional agents, but for other procedures, the risk of complications is similar.