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Endoscopy 2011; 43(5): 400-405
DOI: 10.1055/s-0030-1256182
Original article

© Georg Thieme Verlag KG Stuttgart · New York

Propofol sedation during endoscopy in patients with cirrhosis, and utility of psychometric tests and critical flicker frequency in assessment of recovery from sedation

P.  Sharma1 , S.  Singh2 , B.  C.  Sharma1 , M.  Kumar1 , H.  Garg1 , A.  Kumar1 , S.  K.  Sarin1
  • 1Institute of Liver and Biliary Sciences, Vasant Kunj, Delhi, India
  • 2Department of Hepatology and Anesthesia, Vasant Kunj, Delhi, India
Further Information

S. K. SarinMD 

Institute of Liver and Biliary Sciences

Vasant Kunj
New Delhi 110070
India

Fax: +91-11-23233336

Email: shivsarin@gmail.com

Publication History

submitted 21 August 2010

accepted after revision 1 December 2010

Publication Date:
04 May 2011 (online)

Also available ateRef
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Commentaire de travail de P. Sharma et al., pp. 400Endoscopy 2011; 43(05): 464-464
DOI: 10.1055/s-0031-1291801

Background and study aims: Patients with cirrhosis who undergo endoscopy under sedation could be at increased risk of complications. We assessed the utility of the critical flicker frequency (CFF) in the recovery of cognitive function.

Patients and methods: This was a prospective study in patients with cirrhosis who underwent endoscopy under sedation with propofol in a tertiary care center. The main outcome was deterioration in cognitive function as measured by the number connection test A and B (NCT-A, -B), digit symbol test (DST), serial dotting test (SDT), and line tracing test (LTT) before and 2 h after endoscopy. CFF was recorded before and then every 30 min after endoscopy for the next 2 h.

Results: In the 108 patients there was no deterioration in results of the psychometric tests after the endoscopy (NCT-A 65.2 ± 44.4 vs. 62.4 ± 43.6 s, P = 0.01; NCT-B 110.4 ± 34.7 vs. 109.6 ± 44.6 s, P = 0.45; DST 26.2 ±1 0.0 vs. 26.7 ± 9.9, P = 0.25; SDT 88.6 ± 47.5 vs. 84.3 ± 44.1 s, P = 0.02; LTT 116.6 ± 55.2 vs. 115.4 ± 51.3 s, P = 0.47.) Patients with minimal hepatic encephalopathy (MHE; n = 64) did not show any deterioration in cognitive function at 2 h (NCT-A 87.7 ± 45.4 vs. 84.3 ± 44.9 s, P = 0.06; NCT-B 134.8 ± 65.4 vs. 132.7 ± 58.8 s, P = 0.46; DST 21.4 ± 8.9 vs. 22.2 ± 8.8, P = 0.09; SDT 107.1 ± 53.0 vs. 102.7 ± 48.5 s, P = 0.03; and LTT 131.5 ± 62.2 vs. 129.6 ± 57.2 s, P = 0.46). There was a significant difference between CFF at baseline and at 30 min and 1 h but no difference thereafter in non-MHE patients, MHE patients, and in controls. A total of 30 patients (28 %) had CFF < 38 Hz. In these patients, CFF at 2 h did not significantly differ from baseline CFF (35.9 ± 1.5 vs. 36.1 ± 2.0 Hz; P = 0.19). A total of 10 patients (9 %) had transient hypoxemia and 18 (17 %) had hypotension during the procedure. The endoscopy was completed in all patients.

Conclusions: Propofol is safe in patients with cirrhosis and the CFF is a useful tool for the assessment of recovery from sedation in these patients.

 

Introduction

Upper gastrointestinal endoscopy is routinely performed in patients with chronic liver disease to screen for esophageal and gastric varices [1]. Patients with liver cirrhosis who undergo endoscopy with midazolam could be at increased risk of complications related to sedation, such as precipitation of hepatic encephalopathy or minimal hepatic encephalopathy (MHE) [2] [3]. The use of propofol sedation for endoscopic procedures has increased in recent years. The favorable pharmacokinetic profile compared with traditional endoscopic sedation with benzodiazepines and opioids makes propofol a better choice, especially if deep sedation is targeted. The significantly shorter recovery time and the improved quality of physical and psychomotor recovery after propofol sedation are strong arguments for the use of propofol during endoscopic sedation rather than benzodiazepines in patients with liver cirrhosis [4] [5] [6] [7]. Recently a study by Riphaus et al. [8] concluded that propofol sedation for upper gastrointestinal endoscopy does not cause acute deterioration of MHE and is associated with improved recovery in patients with liver cirrhosis. Similarly, Amorós et al. [9] showed that there were no significant changes in the critical flicker frequency (CFF) before and after propofol sedation in patients previously diagnosed with MHE. They concluded that the use of propofol in the sedation of patients with cirrhosis during endoscopic procedures does not precipitate minimal or overt hepatic encephalopathy.

In these studies cognitive functions were assessed by various paper and pencil tests. However, learning affects the paper and pencil tests if repeated at short intervals of time [8] [9] [10]. CFF is a reproducible parameter with little bias for training effects, education, daytime, or inter-examiner variability. Also, age dependency of the results appears to be negligible in routine use. CFF analysis was found to be sensitive and objective in the quantification of low-grade hepatic encephalopathy, and there is a significant correlation between CFF and the psychometric hepatic encephalopathy score (PHES) battery [11] [12] [13] [14]. We assessed the utility of CFF in the recovery of patients with cirrhosis after endoscopy with propofol.

 

Materials and methods

Consecutive patients with cirrhosis who underwent upper gastrointestinal endoscopy between October 2009 and April 2010 were included in this study. The diagnosis of liver cirrhosis was based on available history, serologic testing, radiologic imaging, and liver histology when available. The staging of cirrhosis was determined by the Child-Turcotte-Pugh (CTP) classification. All patients completed a standard preprocedure history and physical examination to establish current degree of encephalopathy and ascites. All patients with cirrhosis and aged between 18 and 70 years were included in the study. Patients were excluded from the study if they were American Society of Anesthesiology (ASA) physical status class IV or V, had active gastrointestinal bleeding, alcohol intake during the past 6 weeks, hepatocellular carcinoma, previous transjugular intrahepatic portosystemic shunt (TIPS) or other shunt surgery, significant co-morbid illness such as heart, respiratory, or renal failure, and any neurologic disease such as Alzheimer’s disease, Parkinson’s disease, and nonhepatic metabolic encephalopathies. Patients on psychoactive drugs, such as antidepressants or sedatives were also excluded. Patients with visual or mental impairment who were unable to complete the psychometric testing or CFF were also excluded. The study was approved by the ethics committee of the institute and informed written consent was obtained from every patient before enrollment in the study.

 

Psychometric testing

All patients underwent a combination of psychometric tests including number connection test-A and B (NCT-A, -B), digit symbol test (DST), serial dotting test (SDT), and line tracing test (LTT). These tests were easy to administer and could be performed in 30 – 40 min. Patients were labeled as illiterate (those unable to read and write), subgraduate (≤ 12 years of formal education), and graduate (holders of bachelor degree with 15 years of formal education).

For the NCT, subjects needed to connect numbers as fast as possible. For the DST subjects had to accurately and quickly transcribe symbols corresponding to numbers by looking at a key in a timed manner over 90 s. The number of correctly transcribed symbols indicated performance (i. e. a low score means poor performance). In the SDT, subjects placed a dot exactly in the center of large circles arranged in 10 rows, beginning each row on the left side and working towards the right. For the LTT, subjects were required to draw a line between two lines on the paper, staying between the printed lines (neither touching nor drawing over the lines). The test score was the time required to complete the test, including the time needed to correct any errors. Two or more abnormal tests were recommended by Ferenci et al. [15] for the diagnosis of MHE. These tests have been validated in a healthy population and in patients with cirrhosis by our group previously [13] [14]. Tests were considered abnormal when the test score was more than a mean ±2SD from tests scores of age- and education-matched control individuals (n = 170), who were taken from a healthy population and whose results were used to generate the normative values for the psychometric tests.

 

Measurement of CFF threshold

CFF was assessed by the HEPAtonorm Analyzer (Hepatonorm Analyzer; R&R Medi-Business Freiburg GmbH, Freiburg, Germany). It was measured in a quiet, semi-darkened room. Patients were first instructed and trained about the procedure. Flicker frequencies were measured eight times and the mean value was calculated. Measurement of the CFF thresholds was done by intrafoveal stimulation with a luminous diode. By decreasing the frequency of the light pulses from 60 Hz, the CFF threshold was determined as the frequency when the impression of fused light turned to a flickering one. A CFF of < 39 Hz was considered to be abnormal and diagnostic of MHE and a CFF of < 38 Hz was considered to be predictive of future bouts of encephalopathy [11] [12].

 

Assessment of hepatic encephalopathy and MHE

Hepatic encephalopathy was defined according to the West Haven Criteria. MHE was diagnosed when two or more psychometric tests were abnormal (> 2 SD of age- and education-matched controls) [15].

 

Study design

Patients who were eligible for inclusion and provided written informed consent to undergo the endoscopic procedures and to participate in the psychometric hepatic encephalopathy test and CFF were enrolled. All patients were first assessed by an anesthesiologist for eligibility to undergo endoscopy. All patients underwent the mini-mental scale examination (MMSE); if the score was more than 24 then patients underwent psychometric tests (NCT-A and -B, DST, SDT, and LTT) before endoscopy and 2 h after endoscopy. CFF was assessed before endoscopy and then every 30 min after endoscopy for the next 2 h. Both the anesthesiologist and the endoscopist were blinded to the results of psychometric tests and CFF at baseline. The test period of 2 h was used because it is our hospital policy to keep the patient under observation for 2 h after the procedure. The control group consisted of 25 subjects without known prior liver disease and with normal liver function tests at the time of enrollment who were matched to the study population for age and sex (age 42.1 ± 10.2 years; M : F 22 : 3). This study arm was established to estimate the learning effect and any role of endoscopy per se on psychometric tests and on CFF.

 

Sedation protocol

Administration of sedation was performed by a trained anesthesiologist. Associated medical illnesses were graded using the ASA Physical Status Classification System on presentation. The level of sedation attained during the procedure was assessed according to the Modified Observer’s Assessment of Alertness/Sedation Scale recorded on a scale of 0 to 6 [16]. The goal was to induce and to maintain a level of sedation that facilitated completion of the procedure with minimal discomfort to the patient and without cardiorespiratory compromise. The anesthesiologist administering propofol was blinded to the MHE status of the patient. Sedation was initiated using propofol 0.5 – 1.0 mg/kg intravenous bolus until a deep sedation level was reached, followed by an additional intravenous bolus dose of 10 – 20 mg as necessary. Vital signs were recorded with continuous pulse oximetry, electrocardiogram, and automated blood pressure monitoring at baseline (before sedation), throughout the procedure, and during postprocedure recovery. All patients received prophylactic oxygen through a nasal cannula during the procedure. A complication was recorded for the following events: < 90 % on pulse oximetry and a drop in systolic pressure < 20 mmHg from the baseline. Serious complications were defined as complications that required hospital admission, assisted ventilation, or interruption of the procedure.

 

Statistical analysis

Data were expressed as mean ± SD. For a comparison of categorical variables, the chi-squared and Fisher’s exact tests were used, and for continuous variables, a Mann-Whitney test for unpaired data and a Wilcoxon rank sum test for paired data were used as appropriate. The probability level of P < 0.05 was set for statistical significance

 

Results

Between October 2009 and April 2010, 190 patients with cirrhosis were screened; 108 patients (57 %) met the inclusion criteria and were included in the study. The etiology of cirrhosis were: alcohol (n = 31), chronic hepatitis B (n = 36), chronic hepatitis C (n = 15), primary biliary cirrhosis (n = 1), autoimmune hepatitis (n = 4), cryptogenic cirrhosis (n = 20), and hemochromatosis (n = 1). A total of 82 patients (43 %) were excluded from the study due to: history of recent alcohol intake (n = 18), renal impairment (n = 10), hepatocellular carcinoma (n = 10), recent use of drugs affecting psychomotor performance (n = 8), shunt surgery (n = 2), severe medical problem (n = 15), and not willing to undertake psychometric tests/CFF (n = 19). The clinical and demographic characteristics of the patients enrolled are shown in [Table 1]. A total of 25 age-matched patients with no history and biochemical evidence of liver disease who underwent endoscopy due to other reasons served as controls. The characteristics of procedure details are shown in [Table 2]. There was no significant difference between patients with cirrhosis and control patients with respect to propofol dose requirement (160.3 ± 53.2 vs. 158.9 ± 49.8 mg, P = 0.3), induction time (2.2 ± 0.8 vs. 2.3 ± 0.5 min, P = 0.8), shifting to recovery room time (8.5 ± 2.8 vs. 8.4 ± 3.3 min, P = 0.7); however duration of procedure was significantly lower in the control group (9.6 ± 3.2 vs. 3.8 ± 2.2 min, P = 0.002).

Table 1 Clinical and demographic profile of patients.
Parameters Patients (n = 108)
Age, years 40.7 ± 11.8
M:F 90 : 18
Heart rate, minutes 84 ± 12.6
Mean arterial pressure, mmHg 90 ± 16.4
CTP score 8.2 ± 1.5
Child’s status
 A
 B
 C
16
43
49
MELD score 14.8 ± 3.9
MHE, n (%) 64 (59)
AST, median (range), IU/L 45 (21 – 403)
ALT, median (range), IU/L 43(14 – 608)
Serum sodium, mmol/L 135.0 ± 5.4
Variceal size
 None
 Small
 Large
8
40
60
Diagnostic endoscopy 70
Therapeutic endoscopy(EVL) 38
ALT, alanine aminotransferase; AST, aspartate aminotransferase; CTP, Child-Turcotte-Pugh score; EVL, endoscopic variceal band ligation; MELD, model for end-stage liver disease.
Table 2 Characteristics of patients and procedure in patients with cirrhosis (n = 108).
ASA classification
 1
 2
 3
 4
0
30
78
0
Propofol dose, mg 160.3 ± 53.2
MOAAS score 1, n 108
Induction time, minutes 2.2 ± 0.8
Procedure duration, minutes 9.6 ± 3.2
Shifting to recovery room, minutes 8.5 ± 2.8
ASA, American Society of Anesthesiologists (Physical Status Classification System); MOAAS, Modified Observer’s Assessment of Alertness/Sedation Scale.
 

Results of psychometric tests before and after endoscopy

The normative values for the psychometric tests were derived from a group of 131 men and 39 women. The mean age of this group was 38.9 ± 12.7 years (range 19 – 71 years), and the mean duration of formal education was 11.5 ± 3.9 years (range 0 – 18 years). The normative values for the psychometric tests were as follows: NCT-A 31 ± 10 s; NCT-B 56.0 ± 16 s; DST 37 ± 9 s; SDT 55.0 ± 10 s; and LTT 84 ± 16.0 s. All patients were able to complete the tests. Of the 108 patients, the psychometric test results before and after endoscopy were: NCT-A 65.2 ± 44.4 vs. 62.4 ± 43.6 s, P = 0.01; NCT-B 110.4 ± 34.7 vs. 109.6 ± 44.6 s, P = 0.45; DST 26.2 ± 10.0 vs. 26.7 ± 9.9, P = 0.25; LTT 116.6 ± 55.2 vs. 115.4 ± 51.3 s, P = 0.47; SDT 88.6 ± 47.5 vs. 84.3 ± 44.1 s, P = 0.02). The overall results of the psychometric tests before and after endoscopy in patients with MHE, non-MHE, and controls are shown in [Table 3]. There was no deterioration in the time taken to complete the test (NCT, DST, SDT, and LTT) before and after the endoscopy in these patients, in fact the time taken to complete NCT-A and SDT was shorter after the procedure. Of the 108 patients, 64 (59 %) had MHE. In these patients also there was no deterioration in the time taken to complete the psychometric tests before and after the endoscopy ([Table 3]). Results were similar for the control group ([Table 3]).

Table 3 Psychometric tests in patients with cirrhosis and controls before and after endoscopy.
Tests, seconds Non-MHE (n = 44) MHE (n = 64) Controls (n = 25)
Before At 2 hours P Before At 2 hours P Before At 2 hours P
NCT-A 32.5 ± 6.1 30.5 ± 5.7 0.02 87.7 ± 45.4 84.3 ± 44.9 0.06 33.1 ± 5.3 30.7 ± 5.1 0.03
NCT-B 60.4 ± 12.3 59.6 ± 10.6 0.45 134.8 ± 65.4 132.7 ± 58.8 0.46 62.4 ± 12.2 61.2 ± 10.1 0.57
DST 32.2 ± 7.9 32.2 ± 8.4 0.97 21.4 ± 8.9 22.2 ± 8.8 0.09 37.0 ± 5.6 37.0 ± 4.5 1.0
SDT 61.8 ± 15.9 57.5 ± 12.7 0.01 107.1 ± 53.0 102.7 ± 48.5 0.03 58.8 ± 15.9 54.0 ± 11.0 0.02
LTT 95.0 ± 33.1 94.7 ± 32.1 0.90 131.5 ± 62.2 129.6 ± 57.2 0.46 86.5 ± 28.3 87.6 ± 27.1 0.56
DST, digit symbol test; LTT, Line tracing tests; MHI, minimal hepatic encephalopathy; NCT, number connection test; SDT, serial dotting test.
 

CFF before and after endoscopy

CFF was measured before endoscopy and then every 30 min until 2 h after endoscopy. CFF was significantly lower in patients with MHE compared with non-MHE patients (38.6 ± 2.9 vs. 41.4 ± 2.8 Hz, P = 0.001). Baseline CFF in all patients (n = 108) was 39.6 ± 3.2 Hz, and at 30 min (38.3 ± 3.5 Hz), 1 h (38.7 ± 3.4 Hz), 1.30 h (39.8 ± 3.1 Hz), and 2 h (39.8 ± 3.2 Hz). There was a significant difference between CFF at baseline and at 30 min and 1 h but no difference thereafter across the whole group, in MHE patients, or in controls ([Table 4]; [Fig. 1] and [2]). A total of 45 patients (42 %) had CFF < 39 Hz at baseline and 60 (56 %) at 30 min, 57 (53 %) at 1 h, 40 (37 %) at 1.30 h, and 45 (42 %) at 2 h. No patient with CFF > 39 Hz at baseline had CFF < 39 Hz at 2 h. A total of 30 patients (28 %) had CFF < 38 Hz; the CFF for these patients at 2 h did not significantly differ from baseline CFF (P = 0.19), though it was significantly lower at 30 min and at 1 h after endoscopy.

Table 4 Critical flicker frequency (CFF) in patients with cirrhosis at baseline and at follow-up.
Parameter CFF Compared with baseline, P value
Baseline 30 min 1 hour 1.30 hours 2 hours 30 min 1 hour 1.30 hours 2 hours
CFF (n = 108) 39.6 ± 3.2 38.3 ± 3.5 38.7 ± 3.4 39.8 ± 3.1 39.8 ± 3.2 0.001 0.002 0.21 0.17
CFF in MHE patients (n = 64) 38.6 ± 2.9 37.1 ± 3.5 37.6 ± 3.3 38.8 ± 2.9 38.9 ± 3.1 0.001 0.03 0.26 0.08
CFF in non-MHE patients (n = 44) 41.4 ± 2.8 39.9 ± 2.5 40.3 ± 2.8 41.2 ± 2.8 41.1 ± 2.7 0.001 0.004 0.58 0.87
CFF in controls (n = 25) 41.8 ± 3.0 40.0 ± 2.2 40.8 ± 2.7 41.9 ± 2.9 41.9 ± 2.7 0.001 0.01 0.85 0.75
CFF in patients < 38 Hz (n = 30) 35.9 ± 1.5 34.6 ± 2.5 35.0 ± 1.7 36.4 ± 1.8 36.1 ± 2.0 0.001 0.005 0.06 0.19
MHE, minimal hepatic encephalopathy.
Zoom

Fig. 1 Critical flicker frequency in patients with cirrhosis (n = 108) at different time frames following endoscopy under propofol sedation. Dots in bars indicate the mean value. The range is indicated by the vertical limits.

Zoom

Fig. 2 Critical flicker frequency in patients with minimal hepatic encephalopathy (n = 64) after endoscopy at different time frames. Dots in bars indicate the mean value. The range is indicated by the vertical limits.

When patients were categorized into two groups, those having CFF < 39 Hz vs. those ≥ 39 Hz at 1 h, 1.30 h, and at 2 h, no difference was found at baseline in the dosage of propofol, ASA class, or CTP score: 1 h – propofol dose (154.2 ± 45.5 vs. 167.2 ± 60.5 mg, P = 0.2), ASA class (2.7 ± 0.4 vs. 2.6 ± 0.4, P = 0.1), and CTP score (8.3 ± 1.7 vs. 8.1 ± 1.4, P = 0.23); 1.30 h – propofol dose (153.5 ± 41.4 vs. 164.4 ± 59.0 mg, P = 0.3), ASA class (2.8 ± 0.4 vs. 2.7 ± 0.4, P = 0.1), and CTP score (8.4 ± 1.7 vs. 8.1 ± 1.4, P = 0.40); 2 h, propofol dose (159.1 ± 44.3 vs. 161.2 ± 59.1 mg, P = 0.8), ASA class (2.7 ± 0.4 vs. 2.6 ± 0.4, P = 0.2), and CTP score (8.4 ±1.7 vs. 8.0 ±1.4, P = 0.20).

 

Complications related to sedation

There was no severe complication associated with the endoscopic procedure in sedation. Only 10 patients in the cirrhosis group (9 %) and one (4 %) in the control group (P = n. s.) showed transient hypoxemia. Hypotension was seen in 18 patients (17 %) in the cirrhosis group and in two (8 %) of the control group (P = n. s.). Hypoxemia was managed with jaw thrust and chin lifting and by increasing the concentration of inspired oxygen. These complications did not cause the procedure to be stopped in these patients. Six patients were noted to have intraprocedural coughing spasms; however, none of these episodes was associated with significant hypoxemia. No patient showed overt hepatic encephalopathy after 2 h of sedation. None of the complaints required prolonged postprocedure monitoring or unplanned admission.

 

Discussion

In this study 108 patients with cirrhosis underwent upper gastrointestinal endoscopy under sedation with propofol. Following endoscopy there was no deterioration in the results of psychometric tests and CFF after 2h. Propofol is safe for upper gastrointestinal endoscopy in patients with cirrhosis.

Upper gastrointestinal endoscopy is routinely performed to screen for varices in patients with cirrhosis. Patients with hepatic dysfunction who undergo endoscopy are at increased risk for complications related to sedation, although there are few studies quantifying the risk in this population [2] [3] [4]. To prevent the benzodiazepine-induced side effects of conscious sedation in patients with liver disease, some investigators recommend unsedated gastrointestinal endoscopy for these patients [17] [18]. This stands somewhat in contrast to the fact that patients, especially those with liver cirrhosis, often require adequate sedation to ensure tolerance and comfort while undergoing interventional procedures (e. g. band ligation), which is important to enhance compliance if subsequent follow-up endoscopies are required.

MHE prevalence varies in patients with cirrhosis (30 – 70 %) depending upon the modality of diagnosis [19] [20] [21] [22] [23] [24]. In this study, 59 % patients had MHE. MHE affects quality of life and makes patients prone to traffic accidents. Moreover, patients with cirrhosis and MHE more frequently develop episodes of overt hepatic encephalopathy compared with those without MHE. These characteristics of MHE make patients prone to develop overt hepatic encephalopathy when exposed to a precipitant factor such as sedation during endoscopy. In this study none of the 64 patients with diagnosed MHE showed deterioration in psychometric test results or CFF at 2 h after endoscopy.

The psychometric test NCT-A assesses psychomotor function, whereas NCT-B analyzes divided attention and executive function. The DST is a test of attention and processing speed. Similarly, LTT (psychomotor and visuo-spatial) and SDT measure psychomotor abilities [25]. We did not find any deterioration in these test results after endoscopy performed under propofol sedation. NCT-A and SDT showed some improvement. This is probably due to a learning effect seen in patients with cirrhosis if these tests were done as part of a previous trial [8] [9]. But there was no deterioration in these fields in patients with cirrhosis after sedation with propofol.

CFF is a well-established neurophysiological technique to detect a broad spectrum of neurophysiological abnormalities ranging from visual signal processing (retinal gliopathy) to cognitive functions, and CFF < 38 Hz was predictive of further bouts of overt hepatic encephalopathy [11] [12]. CFF is a reproducible parameter with little bias for training effects, education, age, daytime, or inter-examiner variability [11] [12] [13] [14]. Using the CFF cut-off of 39 Hz for MHE [11] and < 38 Hz as a predictive factor for future bouts of encephalopathy, no significant difference was observed at 2 h in these patients compared with at baseline [12].

Propofol is an intravenous anesthetic agent that can be used as a sedative during gastrointestinal endoscopic procedures [26] [27]. It has a favorable pharmacokinetic profile compared with the benzodiazepines and opioids with regard to rapid induction of sedation, faster recovery, and equivalent levels of amnesia [6] [28] [29]. The depth of sedation produced is typically greater than with traditional sedatives used in the outpatient setting. Propofol is rapidly and widely distributed and metabolized throughout the body. Although propofol undergoes hepatic metabolism, no adjustments to dosage are required in patients with chronic liver disease [6]. In the present study, all patients could tolerate propofol without any significant side effects leading to termination of the procedure. Transient hypoxemia (9 %) and hypotension (17 %) were noted but were not significantly different from controls. This was in accordance with previous trials about the safety of propofol in patients with cirrhosis [8] [9]. The study analyzed patients with and without MHE. The number of patients is probably not large enough to make a stratification according to Child stage A, B, or C. Future large studies should be performed to evaluate the effect of propofol in patients with cirrhosis according to Child’s status.

The strength of this study is the use of psychometric tests and CFF in assessing the cognitive functions before and after endoscopy, and it is the largest study to evaluate the effect of propofol in patients with cirrhosis. The anesthesiologist and endoscopist were blinded to the result of the psychometric tests. Limitations include the lack of prolonged follow-up to assess the side effects at later hours after the procedure. In conclusion, propofol is safe for endoscopy and CFF is a valuable tool in evaluating the recovery of sedation in patients with cirrhosis.

Competing interests: None

 

References

S. K. SarinMD 

Institute of Liver and Biliary Sciences

Vasant Kunj
New Delhi 110070
India

Fax: +91-11-23233336

Email: shivsarin@gmail.com

 

References

S. K. SarinMD 

Institute of Liver and Biliary Sciences

Vasant Kunj
New Delhi 110070
India

Fax: +91-11-23233336

Email: shivsarin@gmail.com

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Zoom

Fig. 1 Critical flicker frequency in patients with cirrhosis (n = 108) at different time frames following endoscopy under propofol sedation. Dots in bars indicate the mean value. The range is indicated by the vertical limits.

Zoom

Fig. 2 Critical flicker frequency in patients with minimal hepatic encephalopathy (n = 64) after endoscopy at different time frames. Dots in bars indicate the mean value. The range is indicated by the vertical limits.