Patient-controlled sedation in endoscopy: are patients leading us?

The use of propofol-based sedation in the endoscopy suite has increased enormously throughout the world in the past few years. The main reasons behind this trend are the procedural comfort and patient satisfaction, the reduction in induction and recovery times, and the safety record [1] [2] [3] [4].

The sedation regimen that has been described most often in the literature is probably the nonanesthesiologist-administered propofol bolus, which is endorsed by several societies [5] [6]. However, the perfect sedation regimen is still being sought. The options include: balanced sedation with several other agents including midazolam, fentanyl, alfentanil, and pethidine; propofol continuous infusion; patient-controlled sedation; and target-controlled or automated sedation with systems such as the Sedasys system (Ethicon Endo-Surgery Inc., Cincinnati, Ohio, USA).

This issue of Endoscopy includes a trial by Chiang et al., which compared the clinical outcomes of sedation (recovery time, complications, and satisfaction) between target-controlled propofol infusion (TCI) and manually controlled infusion (MCI) by an anesthesiologist in a same-day upper endoscopy and colonoscopy examination [7]. Between September 2008 and July 2010, 220 low risk patients were randomized (1:1) into two arms. In the TCI arm, patients were administered propofol in order to achieve deep sedation, with an initial serum concentration of 4.0 µg/mL. In the MCI group the patients were inducted with 1.5 mg/kg followed by 6 – 12 mg/kg/h of propofol. The TCI group achieved a shorter recovery time (P  = 0.002), less hypotension, as measured by the duration in which the mean arterial blood pressure remained decreased by > 20 % (P = 0.007), shorter bradypnea time (P = 0.013), and a lower incidence of moderate desaturation (relative risk = 0.50, 95 %CI 0.298 – 0.840).

In another study published in this issue, Mazanikov et al. addressed patient-controlled sedation (PCS) for endoscopic retrograde cholangiopancreatography [8]. The authors performed a well-designed trial with 82 patients who were randomized 1:1 in two parallel arms to receive either propofol on demand (1 mL) or TCI for a concentration of 2 μg/mL. Patients in both arms were administered alfentanil if needed. Propofol consumption, procedural performance, recovery times, and adverse events were evaluated. Propofol consumption was lower in the PCS group (224 ± 101 vs. 306 ± 124 mg; P = 0.002). Alfentanil was needed in more than 70 % of the patients and the mean (± SD) consumption was 0.5 ± 0.4 mg in both groups. Sedation level was deeper in the TCI group (P = 0.002 – 0.035). Anesthesiologist interference in the propofol infusion was needed in only 7 % of the PCS patients. Sedation recovery was faster in the PCS group (P = 0.048). Postprocedural pain and patient satisfaction was similar in both groups.

Both of the studies used alfentanil. This option ensures analgesia and patient satisfaction but limits the external validity and precludes the comparison with propofol mono-sedation, which is the most commonly used sedation regimen.

These trials examined the options available for achieving optimal procedural sedation with propofol-based regimens (effectiveness, safety, recovery time). There is a rapidly growing body of evidence supporting different modalities of sedation; TCI and PCS are two of these options. TCI is more demanding on the sedation team and requires the availability of specific equipment. PCS has the conceptual advantage of allowing the patient to dose the sedation as needed without compromising comfort or safety. In fact, PCS resulted in lighter sedation and lower propofol consumption than TCI in the Mazanikov study while maintaining patient satisfaction. Whether this has a meaningful clinical impact has yet to be confirmed. To date, few data have been reported in the endoscopy field to draw conclusions about these sedation systems but, for TCI in adult surgical patients, no clinically significant differences were demonstrated in terms of quality of anesthesia or adverse events with TCI vs. manually controlled infusion of propofol in a Cochrane meta-analysis [9].

There is little doubt that propofol is currently the ideal agent for endoscopic sedation. There are several protocols of administration, which include bolus, manual infusion, automated infusion, and patient controlled. All of these have achieved acceptable outcomes, although with different levels of evidence to support them.

Still, the “64 million dollar question” right now in most European countries and worldwide, is who should be responsible for (propofol) sedation and for patient care in routine low risk procedures in low risk patients (ASA I-II). The focus on financial aspects rather than rational, evidence-based arguments by some anesthesiology societies, undermines the confidence of the clear statements and guidelines put forward on this topic by national and international gastroenterology societies [4] [5] [6]. However, there is convincing evidence worldwide supporting propofol sedation by nonanesthesiologists.

• References

• 1 Rex DK, Deenadayalu VP, Eid E et al. Endoscopist-directed administration of propofol: a worldwide safety experience. Gastroenterology 2009; 137: 1229-1237
• 2 Wang D, Chen C, Chen J et al. The use of propofol as a sedative agent in gastrointestinal endoscopy: a meta-analysis. PloS one 2013; 8: e53311
• 3 Singh H, Poluha W, Cheung M et al. Propofol for sedation during colonoscopy. Cochrane Database Syst Rev 2008; 4 CD006268
• 4 Riphaus A, Wehrmann T, Weber B et al. S3 Guideline: Sedation for gastrointestinal endoscopy 2008. Endoscopy 2009; 41: 787-815
• 5 Dumonceau JM, Riphaus A, Aparicio JR et al. European Society of Gastrointestinal Endoscopy, European Society of Gastroenterology and Endoscopy Nurses and Associates, and the European Society of Anaesthesiology Guideline: Non-anesthesiologist administration of propofol for GI endoscopy. Endoscopy 2010; 42: 960-974
• 6 Vargo JJ, Cohen LB, Rex DK et al. Position statement: nonanesthesiologist administration of propofol for GI endoscopy. Gastroenterology 2009; 137: 2161-2167
• 7 Chiang MH, Wu SC, You CH et al. Target-controlled infusion vs. manually controlled infusion of propofol with alfentanil for bidirectional endoscopy: a randomized controlled trial. Endoscopy 2013; 45
• 8 Mazanikov M, Udd M, Kylänpää L et al. A randomized comparison of target-controlled propofol infusion and patient-controlled sedation during ERCP. Endoscopy 2013; 45
• 9 Leslie K, Clavisi O, Hargrove J. Target-controlled infusion versus manually-controlled infusion of propofol for general anaesthesia or sedation in adults. Cochrane Database Syst Rev 2008; 3 CD006059