Susanne Eberl

Chapter 5

vs. 1.0) and pain scores (2.59 vs. 4.43). In the midazolam group, 35% of the patients showed

a decrease in oxygen saturation, whereas no adverse events happened in the opioid group.

Remifentanil

Remifentanil is a synthetic opioid with the analgesic potency of fentanyl, but an extremely

short duration of action (begin 30-60 s, peak 2.5 min, termination half-life 8-10 min).

Metabolism takes place by nonspecific esterases. This is useful especially in situationsmaking

a predictable termination of its effect necessary. Akcaboy et al.

showed that remifentanil

during colonoscopies – used as bolus injection combined with a low dose continuous

infusion (0.05 µg/kg/min) and 2mgmidazolam - provides appropriate amnesia and sedation

compared with propofol. Analgesia was even better with lower discomfort scores among

patients. Drawback of remifentanil, however, was that it caused nausea and vomiting

during the recovery phase and delayed patients` discharge. Haemodynamic instability with

a significant decrease in heart frequency, NIBP, and impaired oxygen saturation levels were

additional disadvantages of remifentanil bolus injection. Nonetheless, gastroenterologists`

and patients` satisfaction was higher and duration of colonoscopy was shorter compared

with the propofol group. Probably the more conscious sedated patient cooperated more

easily. Similar results were reported by Fanti et al.

using remifentanil patient controlled

analgesia (PCA) (0.5 µg/kg) in combination with midazolam.

Moerman et al.

compared high-dose remifentanil (startingwith 0.5 µg/kg as bolus injection

with a continuous infusion of 0.2 µg/kg/min) with propofol (starting with 1 mg/kg as bolus

injection with a continuous infusion of 10 mg/kg/h). Both combinations created a sufficient

condition to perform colonoscopy. Emergence times and recovery of cognitive function

were faster in the remifentanil group and haemodynamic disturbances were reduced

compared to propofol. However, a significant problem in the remifentanil group was the

respiratory depression rate. Patients in the propofol group were more satisfied than in the

remifentanil group, probably because of the deeper sedation level caused by propofol.

Greilich et al.

compared remifentanil versus meperidine in older patients undergoing

colonoscopy. Although overall satisfaction was the same in both groups, patients treated

with remifentanil showed higher scores for anxiety and pain compared to the meperidine

group.

In a recent study by Manolaraki,

safety and efficacy of a standard sedation combination

(midazolam and pethidine) during colonoscopy were compared with remifentanil (starting

with a bolus of 1 µg/kg for 1 min combined with a continuous infusion of 0.05-0.2 µg/

kg/min). Although mean levels of pain with remifentanil were higher than those with

midazolam and pethidine, patients and endoscopists were likewise satisfied in both groups.

Respiratory depression rate was significantly lower in the remifentanil group, most likely

due to avoiding bolus injection of remifentanil and preferring careful titration. Importantly,