Propofol Requirements for Gastrointestinal Endoscopy in Patients Older than 75 Years Old Endoscopy sedation in Elderly with Propofol

Introduction

Gastrointestinal endoscopies are invasive, unpleasant, and sometimes painful procedures. For this reason, sedation is essential to reduce the anxiety, pain, and also to increase their efficacy. Propofol is considered the best single sedation agent for endoscopy [1] , mainly because of its favorable pharmacokinetics profile that make it a safe and effective drug compared with traditionally endoscopic sedation drugs [2, 3]. Propofol (2-6 diisopropylphenol) is a hypnotic drug with minimal analgesic properties. It is highly lipophilic, and thus can rapidly cross the blood-brain barrier resulting in an early onset of action (30-40 seconds). The depth of sedation increases in a dose-dependent manner, but his short half- life (4 minutes) regardless of the length or depth of the sedation favors a prompt recovery (10 to 20 minutes after discontinuation) with a pleasing awakening, providing an outstanding comfort for the patients. With regard to side effects, it can induce a dose-dependent decrease in conscience, blood pressure and heart rate, and that’s why its use is recommended under close supervision by trained healthcare personnel and using adequate surveillance with at least pulse O2 saturation, heart and respiratory rate and blood pressure monitoring. To date, no pharmacological antagonist has been developed [4, 5]. Propofol is contraindicated in patients allergic to propofol, and in patients at risk of bronco aspiration or with low ejection fraction. Sedation in gastrointestinal endoscopy performed by a specially trained nurse, guided by the endoscopist, is increasingly common in the European countries and it’s known as NAAP (non-anesthesiologist administered propofol) [6]. It is important that the endoscopist have an appropriate management of sedation with careful training and knowledge about how propofol behaves in different settings or sort of patients. Of note, the European population has a high prevalence of elderly patients. Considering this issue, it is mandatory to have precise information about the dosage needed to achieve a safe sedation level in aged patients in which comorbidities will make them more fragile than the young ones. There are numerous published studies supporting the efficacy and safety of this technique, showing a rate of complications equal to, or lower than traditional sedation, in which propofol is administered during endoscopic procedures based on the weight, age and clinical status of the patient. There is literature on the safety of sedation with propofol in elderly patients in which lower doses are recommended [7, 8]. However, there is lack of clear published data regarding the dose of propofol to be used in this group of patients in whom the dose per kg of weight may be excessive to reach a safe level of sedation [9, 10]. We performed a prospective study to establish the dose of propofol in patients ≥75 years compared with patients <75 years and to evaluate the safety of propofol when is administered by non-anesthesiologist in this population.

Material and Methods

The study protocol was previously approved by the local Committee for Human Studies. Between June 2012 and March 2014, all endoscopic procedures and safety data were prospectively recorded at the endoscopy unit of a university hospital. To homogenize both groups, only diagnostic procedures were included. Patients <18 years, therapeutic procedures not sedated by endoscopist, incomplete procedures due to reasons not related with sedation, and patients with upper and lower endoscopies performed on the same day were excluded. Prior to the procedure, a history of risk factors was taken from all patients leading to a risk stratification based on the criteria of the American Society of Anesthesiologists (ASA). Demographical and clinical data recorded from all patients were age, gender, weight, height, type of endoscopic intervention performed, clinical indication, complications related to sedation or to the endoscopic procedure, and dose of propofol. Oxygen was continuously administered on a routine basis through a nasal probeat 2L/min. Heart rate and blood oxygen saturation levels were continuously monitored. Blood Linette AJ, et al. Propofol Requirements for Gastrointestinal Endoscopy in Patients Older than 75 Years Old Endoscopy sedation in Elderly with Propofol. Gastroenterol Hepatol Int J 2016, 1(1): 000101.

pressure was recorded before, during and after the procedure. All physicians and endoscopy nurses were specially certified for the administration and management of possible risks associated with the use of propofol. To reduce variability and determine whether the differences between the dose of propofol in both groups were only related to age, all patients ≥75 years were matched on a 1:1 basis with the <75 years group in terms of weight, body mass index (BMI) and endoscopic procedure. All esophagogastroduodenoscopies (EGDs) and colonoscopies received an initial dose of propofol 0.5-1 mg/kg. Colonoscopies also received a fixed dose of 50 mcg of fentanyl. Subsequently, boluses of 10-20 mg propofol were administered to maintain an adequate level of sedation. Mild adverse events were defined as those not requiring the interruption of the procedure: a transitory drop in peripheral oxygen saturation below 90%, decreases in the mean arterial pressure of more than 25% and decreases in the heart rate of more than 20%. Mild adverse events resolved spontaneously or with simple maneuvers (chin-lift maneuver, volume expansion, atropine administration). Severe adverse events were defined as those that required interruption of the procedure (the need for intervention with positioning of a tracheal tube, cardiac arrest or death). A statistical analysis was performed with the SPSS v20.0 program. Results are reported as frequencies or means ±SD plus 95% confidence interval of the mean.

Results

Between June 2012 and March 2014, 10,237 endoscopic procedures were performed. After exclusion criteria we analyzed a total of 6,121 diagnostic EGDs and colonoscopies. There were 439 diagnostic EGDs and 307 diagnostic colonoscopies performed in patients ≥75 years. The mean age was 81±4. When compared with patients <75 years, there were significant differences between groups in mean propofol dose, and mild adverse events. No serious adverse events occurred. Patients ≥75 years required significantly less propofol than patients <75 years, (72.99±37.4mg) vs. (120.54±41.8mg for EGDs) (p< 0.001) and (80.59±34mg) vs. (129.12± 55.9mg) (p<0.001) for colonoscopies (39.4% less in EGDs and 37.5% in colonoscopies). Table 1 shows the demographics, endoscopic procedures, propofol dose and adverse events in both groups.

Copyright© Linette AJ.

Discussion

Our study is a prospective investigation about sedation in elderly patients undergoing gastrointestinal endoscopy , which confirms what other studies demonstrate : this population requires less propofol to reach an adequate level of sedation [8, 11, 12]. We selected the mentioned ̈ 75 years old ̈ as cut point age , considering that doing so we would be able to identify a group of patients in which comorbidities might be present, it is representative of our specific population with a high life expectancy and easily reproducible. Indeed we found another study in which the same cut point age was used for a similar analysis [13]. We also estimate how much less propofol they need when compared with younger patients. To our knowledge there is only one study, performed by Heuss, et al. [7], where the difference in the dose of propofol was estimated. In their prospective study, patients older than 85 years old required 60-65% less propofol than youngers. Compared with this study, our investigation provides remarkable information regarding the dose of propofol used, in a very strictly selected population, where therapeutic procedures were excluded to avoid the risk of biases. Our study clearly reflects the dose of propofol needed by the patients as per their age, and not per the duration of the procedure or the need of therapeutically intervention. Moreover, our patients were matched according their BMI on a 1:1 basis to have a clear picture of what was Linette AJ, et al. Propofol Requirements for Gastrointestinal Endoscopy in Patients Older than 75 Years Old Endoscopy sedation in Elderly with Propofol. Gastroenterol Hepatol Int J 2016, 1(1): 000101.

that elderly patients need less propofol than younger patients. But how much less? This study demonstrates Copyright© Linette AJ.

that patients ≥75 years globally require almost 40% less propofol than patients <75 years to achieve a safe sedation. These results support the use of a lower dose of propofol in the elderly, and also demonstrate that sedation administered by non-anesthesiologists is safe in this population.