Date of Award
Master of Medicine (MMed)
Dr. Vitalis Mung'ayi
Dr. Ednah Kemunto Gisore
Dr. Samina Mir
Anaesthesiology (East Africa)
Background: A wide variety of sedation techniques are employed to facilitate various invasive diagnostic and therapeutic procedures. Increasingly, propofol is emerging as the preferred sedative agent. Traditionally, it has been administered as intermittent boluses to achieve deep sedation to facilitate gastrointestinal endoscopy. Propofol target controlled infusion can be employed to provide suitably conducive conditions for this purpose.
Objective: The primary objective sought to compare the proportion of hypoxia between the study group receiving intermittent boluses of propofol at 0.25mg/kg as needed, and the other receiving target-controlled infusion of propofol at 2.5mcg/ml during upper gastrointestinal endoscopy. The secondary objectives were to compare the occurrence of hypotension, bradycardia, and the time to wake up between the two groups.
Primary outcome measure: Decrease in oxygen saturation below 90 percent (SpO2 <90%)
Secondary outcome measures: Decrease in systolic blood pressure of more than 20% from baseline; decrease in heart rate to less than 50 beats per minute.
Study design: prospective, single centre, randomized controlled trial
Study setting: The Aga Khan University Hospital, Nairobi.
Sample size: One hundred and seventy-six participants were enrolled; 88 belonging to the intermittent bolus arm and 88, to the target-controlled infusion arm.
Study population: Included all ASA I and II patients between the ages of 18 and 65 years scheduled to undergo upper gastrointestinal endoscopy (oesophagogastroduodenoscopy) under sedation.
Sedation procedure: One hundred and seventy-six participants were allocated randomly into one of two groups corresponding to the mode of propofol used for sedation (a) Premedication with midazolam 0.05mg/kg added to an initial bolus of propofol 1mg/kg, followed by repeat boluses of 0.25mg/kg as needed (B, n = 88) and (b) Premedication with midazolam 0.05mg/kg added to an initial target effect-site concentration of 4mcg/ml, followed by maintenance target effect-site concentration of 2.5mcg/ml, titrated upward or downward by 0.5mcg/ml from baseline infusion rate as needed (T, n = 88). Oxygenation and haemodynamic parameters were evaluated by determining oxygen saturation, blood pressure and heart rate immediately before administering the sedative and at 2.50, 5.00, 7.50 and 10.00 minutes. Standard care was, in addition to the above, provided.
Data collection: A data collection tool was used to record data (refer to appendix V). Patients’ baseline vital signs, including blood pressure, heart rate and oxygen saturation were entered. Any occurrence of oxygen desaturation below 90% in both study groups was also recorded. The sedation starting time, stopping time, waking up time and overall duration of time to recovery of participants in each study arm was recorded.
Results: In this study, 176 adults undergoing non-emergent upper gastrointestinal endoscopy participated in the study; 88 (50%) allocated to the intermittent bolus arm and 88 (50%) to the target controlled infusion group. More hypoxic episodes were observed in the intermittent bolus group 28/88 (31%) compared to the TCI group 16/88 (18%), with statistically significant association between control and the incidence of hypoxia: Chi square test, p=0.037. There were more hypotensive episodes in the TCI group 30/88 (34%) than in the bolus group 24/88 (27%) but not achieving statistical significance: Chi square test for association X2(1) = 0.962, p=0.327. A single episode of bradycardia was observed in one study subject in the bolus group and none in the TCI arm. The time to recovery between the two groups was comparable, with 18.84 ± 10.76 minutes in the bolus group and 19.72 ± 9.27 minutes in the TCI group; no statistically significant difference was shown: Student’s t-test, p=0.0564.
Conclusion: We therefore conclude that target controlled infusion of propofol at 2.5mcg/ml is associated with fewer episodes of hypoxia compared to intermittent bolus administration of the same agent at 0.25mg/kg as needed. TCI therefore provides a safer alternative to the latter propofol sedation technique in terms of sustaining optimal oxygenation during OGD in adult patients. Similar hemodynamic profiles as well as comparable time to recovery were demonstrated by these two sedation techniques.
Ndosi, C. (2017). A Randomized Controlled Trial comparing the proportion of Hypoxia in Sedated Adults undergoing Upper Gastrointestinal Endoscopy using Target Controlled Infusion of Propofol Versus Intermittent Boluses. (Unpublished master's dissertation). Aga Khan University, East Africa.