Propofol for conscious sedation?

Sedation for GI Endoscopy in the Morbidly Obese: Challenges and Possible Solutions

With the increasing prevalence of obesity and morbid obesity, this subgroup's contribution to patients presenting for elective procedures requiring sedation is significant. Gastrointestinal (GI) procedures clearly form the largest group of such procedures. These procedures may be intended to treat obesity such as the insertion of an intragastric balloon or one or more unrelated procedures such as a screening colonoscopy and (or) diagnostic/therapeutic endoscopy. Regardless of the procedure, these patients pose significant challenges in terms of choice of sedatives, dosing, airway management, ventilation, and oxygenation. An understanding of dissimilarity in the handling of different groups of medications used by an anesthesia provider and alterations in airway anatomy is critical for providing safe sedation. Administration of sedative medications and conduct of anesthesia requires dose modifications and airway adjuncts. In this review, we discuss the above issues in detail, with a particular focus on GI endoscopy.

The dexmedetomidine "augmented" sedato analgesic cocktail: An effective approach for sedation in prolonged endoscopic retrograde cholangio-pancreatography

BACKGROUND AND AIMS

In absence of any published standard guideline for sedation or anesthesia practice for prolonged therapeutic "endoscopic retrograde cholangio-pancreatography (ERCP)", safe and cost-effective sedation protocol is the need of the hour. Our study aims to evaluate the efficacy of a dexmedetomidine as an add-on for prolonged deep sedation for ERCP and to compare three deep sedation regimens regarding safety and efficacy.

MATERIAL AND METHODS

Forty-five consecutively enrolled patients planned for therapeutic ERCP and assumed to have prolonged procedural duration (>50 min) were divided into three groups in a randomized assessor blinded fashion. Group 1 received propofol and midazolam, Group 2 received the sedato-analgesic cocktail containing ketamine-propofol-midazolam-pentazocine, and the Group 3 received sedate-analgesic cocktail plus dexmedetomidine infusion under monitoring of vital parameters and according to the judgment of the concerned anesthesiologist. Total propofol requirement, episodes of gagging, oxygen desaturation, changes in mean blood pressure (MBP), recovery and satisfaction score of endoscopist, anesthetist and patient were noted and analyzed statistically using one way ANOVA with Bonferroni correction and Chi-square test.

RESULTS

Mean propofol requirement, incidences of gagging and oxygen desaturation was significantly less in Group 2 and 3 compared to Group 1. MBP was more stable and recovery was faster in Group 3. Anesthetist's satisfaction was more with Group 2 and even more with Group 3.

CONCLUSIONS

The sedato-analgesic cocktail was superior to the conventional propofol-midazolam regimen, dexmedetomidine as add-on increased the efficacy and safety of sedate-analgesic cocktail. It reduces propofol requirement, helps to maintain the patient in a safe and more stable level of sedation and increases satisfaction of the anesthetist.

Review of propofol and auxiliary medications used for sedation

The sedative-hypnotic propofol (2,6-diisopropylphenol) is being increasingly used for sedation during painful diagnostic and therapeutic procedures in adults and children. The purpose of this article is to present a general overview of the use of propofol for endoscopic sedation. Advantages and disadvantages of using propofol for sedation, as well as its pharmacokinetics, preparation for use, dosing for endoscopic sedation, auxiliary sedative and analgesic medication options, methods of administering, adverse effects with interventions, recovery, and patient-physician satisfaction are discussed. Finally, next steps necessary to optimize future use of propofol are suggested.

A literature review of the safety and efficacy of using propofol for sedation in endoscopy

A 2007 survey of members of the Society of Gastroenterology Nurses and Associates identified a need for more evidence regarding sedation medications including propofol. Therefore, the Cochrane Database of Systematic Reviews, Cochrane Database of Randomized Clinical Trials, MEDLINE, CINAHL, EMBASE, and the National Guideline Clearinghouse (http://www.guideline.gov) databases were individually searched using the term propofol, limited to human, English, 2000-2009, review articles, and randomized clinical trials. A total of 46 resources contributed to this review, with emphasis on 16 studies ranging from retrospective chart reviews to double-blind, randomized controlled trials. Nonanesthesia personnel-administered propofol, including that administered by specially trained nurses under the supervision of an endoscopist, appears to be safe with minor, easily resolved, adverse events occurring in less than 1% of patients. These minor adverse events included four studies reporting hypoxemia requiring occasional intervention, three studies reporting hypotension, and two studies reporting bradycardia. No patients required tracheal intubation, and no deaths were reported.

Modulation of sinusoidal and canalicular elimination of bilirubin-glucuronides by rifampicin and other cholestatic drugs in a sandwich culture of rat hepatocytes

AIM

Drug-induced hyperbilirubinemia has been shown to often be derived from modulation of the expression and activity of hepatobiliary transporters. In this study we examined the interactions of some therapeutic agents, which have been shown to cause cholestasis, with the elimination of bilirubin-glucuronides, in order to clarify whether these drugs modify the activity of Mrp2 and Mrp3 directly.

METHODS

The modulation of bilirubin-glucuronide elimination with rifampicin, probenecid, indomethacin and benzbromarone was assayed in sandwich cultured rat hepatocytes.

RESULTS

All the drugs studied decreased the canalicular transport, but modified the sinusoidal efflux differently. Rifampicin and probenecid stimulated the sinusoidal efflux, shifting the elimination of bilirubin-glucuronides to the sinusoidal domain (biliary excretion index: 3.9 +/- 1.2; 22.7 +/- 7.4 vs. 56.6 +/- 1.5 and 56.8 +/- 5.5). However, the overall elimination of bilirubin-glucuronides did not change significantly. In contrast, indomethacin and benzbromarone inhibited bothtransport processes, resulting in the decrease of the overall bilirubin-glucuronide elimination (61 +/- 22; 56 +/- 5% of the control). Rifampicin, indomethacin and benzbromarone decreased 5,(6)-carboxy-2',7'-dichlorofluorescein transport by multidrug resistance-associated protein (Mrp)2 as visualized by confocal laser microscopy and in vesicular transport experiments. Interestingly, rifampicin decreased the MRP3 activity in vesicular transport experiments using 17-beta-estradiol-17-beta-D-glucuronide as substrate, in contrast to that observed in bilirubin-glucuronide transport experiments.

CONCLUSION

Here we show that the interactions of drugs on hepatobiliary transporter proteins may be identified in vitro in a sandwich culture of hepatocytes, in which canalicular and sinusoidal transport can be studied separately.

Analysis of liver function in renal transplant recipients undergoing C2-monitoring for cyclosporine

There exists no systematic evaluation of liver function in renal allograft recipients undergoing C2-monitoring with Neoral [cyclosporine A (CsA)-microemulsion]. In the present cohort analysis, we compared the hepatic profiles of C2-monitored (n = 80), C0-monitored (n = 81), and non-CsA-treated renal allograft recipients (n = 29), transplanted between 1/1999 and 2/2004 in our institution. While the C2-targets were set in accordance with (n = 72) or below (n = 8) the consensus on Neoral (1500 +/- 200 ng/ml), non-CsA-patients received FK506 (n = 29), partially in combination with rapamycin (n = 13) as primary immunosuppression. Analysis of maximum hepatic laboratory parameters and also repeated measures by anova within 30 days post-transplant revealed highly significant elevations of direct, indirect and total bilirubin, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and lactate dehydrogenase (P < 0.001) in the C2-group, in comparison with the C0- and the non-CsA-group. Bilirubin-levels were by far the most affected of all hepatic parameters, and correlated with C2-levels (r2 = 0.62). Seventeen CsA-patients had excessive bilirubin-elevations (>4 mg/dl) and were therefore considered to be 'CsA-sensitive' [14 C2-patients (17% of all C2-patients), 3 C0-patients (4% of all C0-patients)]. Bilirubin- and the other parameter elevations in these patients were reversible upon withdrawal or lowering of CsA. Most 'CsA-sensitive' patients (n = 12, 70%) displayed pre-transplant hepatic impairment, indicating a pre-existing liver instability. Collectively, our data emphasize the need for increased awareness toward individual predispositions for CsA-sensitivity.

Cholestasis in pregnancy associated with ciclosporin therapy in renal transplant recipients

Obstetric cholestasis (OC) presents with pruritus in the second half of pregnancy and is associated with increased risk of foetal distress, intra-uterine death and premature delivery. From a tertiary referral, renal-obstetric clinic, we report the occurrence of OC in 5/23 pregnancies of women with renal transplants maintained on ciclosporin treatment (European incidence 0.1-1.5% of pregnancies). All required premature delivery for foetal reasons at 33-37/40 (median 34/40). Ciclosporin, at therapeutic concentrations, inhibits bile salt excretion pump (BSEP) function in rats and humans. We propose that OC developed in our patients because the mild inhibition of the canalicular pumps by ciclosporin was only revealed in pregnancy when increases in progesterone metabolites overwhelmed pump function. We suggest that all pregnant women receiving ciclosporin should be closely monitored from the second trimester for the development of OC. If detected, enhanced foetal and maternal monitoring to optimize time of delivery and pregnancy outcome is required.

Identification of a novel 974C-->G nonsense mutation of the MRP2/ABCC2 gene in a patient with Dubin-Johnson syndrome and analysis of the effects of rifampicin and ursodeoxycholic acid on serum bilirubin and bile acids

Rifampicin (RIF) and ursodeoxycholic acid (UDCA) therapies have beneficial effects in chronic cholestatic diseases. These may result in part from the induction of multidrug-resistance protein 2 (MRP2/ABCC2) expression in the liver and kidney. However, the precise mechanisms by which RIF and UDCA act in cholestasis remain unclear. In the present study, we report the effects of chronic administration of both drugs in a patient with Dubin-Johnson syndrome (DJS), an inherited autosomal recessive disorder characterized by the absence of functional MRP2 protein at the canalicular hepatocyte membrane. A novel 974C-->G nonsense mutation was identified in the MRP2 gene sequence from this patient. RIF induced further increase in conjugated bilirubinemia, whereas concomitant administration of RIF and UDCA led to a dramatic rise in serum bile acid concentrations. These biochemical effects, which are in marked contrast to those observed in cholestatic settings, were concomitant with an increased MRP3, but not MRP4, expression on basolateral hepatocyte membrane. Such findings highlight the key role of MRP2 in the pharmacological properties of RIF and UDCA and suggest that both drugs should be used with caution in pathologic settings in which MRP2 expression may be downregulated, as in advanced stage of cholestatic diseases.

Diphenhydramine as an adjunct to sedation for colonoscopy: a double-blind randomized, placebo-controlled study

BACKGROUND

Intravenous benzodiazepines in combination with opiates are used to achieve moderate sedation for colonoscopy. Although effective, these agents have potential adverse effects, such as respiratory depression and hypotension. Diphenhydramine hydrochloride possesses central nervous system depressant effects that theoretically could provide a synergistic effect for sedating patients.

OBJECTIVE

The objective was to assess the efficacy of adding diphenhydramine hydrochloride as an adjunct to improve sedation and to reduce the amount of standard sedatives used during colonoscopy.

DESIGN

We conducted a prospective, randomized, double-blind, placebo-controlled study.

SETTING

The study was conducted in a university hospital with an active GI fellowship training program.

PATIENTS

The study group comprised 270 patients undergoing screening/diagnostic/therapeutic colonoscopy were enrolled.

INTERVENTIONS

Patients were randomized to receive either 50 mg of diphenhydramine or placebo, given intravenously 3 minutes before starting conscious sedation with intravenous midazolam and meperidine.

MAIN OUTCOME MEASUREMENTS

The main outcome measure was anesthetic effect as assessed by the endoscopy team and by the patient; quantity of adjunctive sedatives to achieve adequate sedation.

RESULTS

Of 270 patients, data were analyzed for 258 patients, with 130 patients in the diphenhydramine group and 128 patients in the placebo group. There was a 10.1% reduction in meperidine usage and 13.7% reduction in midazolam usage in favor of the diphenhydramine group. The mean evaluation scores as judged by the faculty, the fellows, and the nurses were statistically significant in favor of the diphenhydramine group. In addition, patient scores for overall sedation and pain level favored the group that received diphenhydramine.

CONCLUSIONS

Intravenous diphenhydramine given before initiation of standard sedation offers a significant benefit to conscious sedation for patients undergoing colonoscopy.

Capnography in the Gastroenterology Lab

This article provides the reader with information and education regarding the use of capnography for both adult and pediatric patients undergoing procedural sedation during endoscopy by: reviewing the basics of capnography, in addition to the physiology of ventilation and oxygenation; illustrating how capnography may provide an earlier warning of hypoxemia than does pulse oximetry; briefly discussing current guidelines for procedural sedation and the potential role of capnography; and reviewing clinical situations causing changes in the capnogram waveforms and the nursing interventions that should be made in response to such changes.

Propofol for Sedation in the Endoscopy Setting

Intravenous sedation is routinely administered for endoscopic examinations to help alleviate patient anxiety and discomfort. The goal of moderate sedation is to provide patient comfort to facilitate the completion of the procedure. Nurse administration of intravenous meperidine and midazolam under the direct supervision of the gastroenterologist is the traditional method for achieving this outcome. More recently, physicians have been requesting monitored anesthesia care for the administration of propofol when performing procedures expected to be technically difficult. Propofol is a rapid acting sedative-hypnotic that produces the desired level of consciousness without the residual sedative effect that often persists with the use of benzodiazepines and analgesics. This article reviews current literature regarding the use of propofol for sedation of patients in the endoscopy setting, and highlights the trends in research that may impact future nursing practice.

Taurocholate transport by hepatic and intestinal bile acid transporters is independent of FIC1 overexpression in Madin-Darby canine kidney cells

BACKGROUND

Mutations in the human familial intrahepatic cholestasis gene, FIC1, result in progressive familial intrahepatic cholestasis type 1 in children and benign recurrent intrahepatic cholestasis. The present study was performed to determine whether FIC1 transports bile acids and/or influences the activity of apical bile acid transporters.

METHODS

The apical secretion assay utilized transfected Madin-Darby canine kidney (MDCK) cells, which stably express the bile acid uptake protein, Na+/taurocholate co-transporting polypeptide (NTCP). These cells were then transiently transfected with FIC1 and/or the bile salt export pump (BSEP) and were grown on Transwell filters to form a polarized monolayer. [(3)H]Taurocholate was added to the basal medium and the taurocholate secretion was measured in the apical medium. A second assay, apical uptake assays, utilized polarized MDCK-II cells, which were transiently transfected with FIC1, FIC1 mutants and/or the apical sodium-dependent bile acid transporter (ASBT). [(3)H]Taurocholate was added to the apical media and intracellular uptake of taurocholate was measured.

RESULTS

Apical secretion assays: FIC1 expression in MDCK/NTCP cells had no effect on taurocholate secretion compared to controls. In contrast, apical secretion of taurocholate in BSEP-transfected cells was approximately twofold higher than in non-transfected MDCK/NTCP cells (P < 0.01). The BSEP-mediated secretion was unaffected by co-transfection with FIC1. Apical uptake assays: taurocholate uptake in ASBT expressing cells was 6.5-fold higher than in controls and was unaffected by co-transfection of cells with FIC1 or FIC1 mutants.

CONCLUSIONS

These results indicate that FIC1 does not transport taurocholate and, when overexpressed in MDCK cells, had no effect on the function of BSEP or ABST.

Propofol or Process

Due to increased public awareness, the number of endoscopic procedures performed per year is rapidly increasing. In lieu of expanding endoscopy units, current practices are being reviewed to improve unit efficiency without compromising patient care. Changing from a traditional medication regimen of demerol/versed or fentanyl/versed to propofol for moderate sedation is currently controversial. Studies using propofol are being conducted to measure recovery times, safety of administration by healthcare providers other than anesthesia providers, cost/benefit ratios, and patient satisfaction. In order to measure the benefits of propofol versus a traditional medication regimen, a retrospective review of 1,056 charts was conducted to evaluate the difference in procedure and post-procedure time between sedation groups before and after a process change. In this study, the use of propofol was associated with a statistically significant shorter mean procedure time (p <.001) and nonsignificant post-procedure time (p =.056) than a traditional regimen; however, a statistically significant reduction in mean times was demonstrated by changes in process (p <.001). The use of propofol demonstrated an actual total time savings of 5.3 minutes per case after the process change. This difference was not large enough for the authors to change current practice of traditional medication for moderate sedation when all other issues related to propofol were taken into consideration.

Propofol for procedural sedation in children in the emergency department

STUDY OBJECTIVE

We determine the safety and efficacy of propofol sedation for painful procedures in the emergency department (ED).

METHODS

A consecutive case series of propofol sedations for painful procedures in the ED of a tertiary care pediatric hospital from July 2000 to July 2002 was performed. A sedation protocol was followed. Propofol was administered in a bolus of 1 mg/kg, followed by additional doses of 0.5 mg/kg. Narcotics were administered 1 minute before propofol administration. Adverse events were documented, as were the sedation duration, recovery time from sedation, and total time in the ED.

RESULTS

Three hundred ninety-three discrete sedation events with propofol were analyzed. Procedures consisted of the following: fracture reductions (94%), reduction of joint dislocations (4%), spica cast placement (2%), and ocular examination after an ocular burn (0.3%). The median propofol dose was 2.7 mg/kg. Ninety-two percent of patients had a transient (<or=2 minutes) decrease in systolic blood pressure without clinical signs of poor perfusion. Nineteen (5%) patients had hypoxia, 11 (3%) patients required airway repositioning or jaw-thrust maneuvers, and 3 (0.8%) patients required bag-valve-mask ventilation. No patient required endotracheal intubation.

CONCLUSION

Propofol sedation is efficacious and can be used safely in the ED setting under the guidance of a protocol. Transient cardiopulmonary depression occurs, which requires vigilant monitoring by highly skilled practitioners. Propofol is well suited for short, painful procedures in the ED setting.