Background

Esophagogastroduodenoscopy (EGD), also known as upper gastrointestinal endoscopy, is a diagnostic procedure performed most commonly by a gastroenterologist.1 An EGD procedure is a combination of three distinct procedures that are typically performed together: esophagoscopy, gastroscopy and duodenoscopy.1 Esophagoscopy procedures examine the inside of the esophagus for hiatal hernia, polyps, strictures, and so on. Gastroscopy procedures examine the inside of the stomach for ulcers, polyps, inflammation, whereas duodenoscopy procedures examine the inside of the duodenum for inflammation or diverticulosis.1

The Centers for Disease Control and Prevention notes that over 1.1 million EGD procedures were performed in 2010 in in-patient settings alone.2 Esophagogastroduodenoscopy procedures are performed for a number of reasons, including: gastroesophageal reflux disease, abdominal pain, obtaining biopsies and locating a source of bleeding from the gastrointestinal tract.3 Today, in the US, EGD procedures are performed under minimal sedation, moderate sedation, deep sedation or general anesthesia, with or without the use of topical anesthesia. Moderate sedation is the most commonly used technique for EGD procedures and is defined as a drug-induced depression of consciousness following the administration of sedatives and/or analgesics in which tactile or verbal stimulation arouses the patient.4 Moderate sedation is the administration of sedatives, analgesics and potentially hypnotics to provide varying depths of sedation tailored to an individual patient's needs.4 Moderate sedation is a continuum of sedation and it is difficult for the anesthesia provider to predict how individual patients will respond to the drugs administered. Patients under moderate sedation may experience a sedation-induced compromise of the airway; or adverse physiological responses to the drugs administered. Therefore, it is essential for anesthesia providers to provide monitored anesthesia care for moderate sedation with a plan to intervene and convert to general anesthesia if necessary to maintain integrity of the airway.4

The pharynx, which is divided into the following compartments: nasopharynx, oropharynx and hypopharynx, can be topically anesthetized with lidocaine in patients undergoing EGD procedures. Historically, topical lidocaine was administered without sedation to blunt the gag reflex as the endoscope passed into the esophagus.5 In fact, Heuss et al.6^(p.1207) states that "topical pharyngeal anesthesia has been the standard preparation for endoscopy in non-sedated patients since the 1970s." Additionally, topical lidocaine reduces the risk of oversedation and decreases the cost of the EGD procedure by reducing recovery time and nursing staff needs.7 Sedation is considered a depression of consciousness; whereas, oversedation is a level of sedation that exceeds the intended therapeutic level of sedation, and is associated with potential harm, such as respiratory depression as a result of decreased ventilatory drive.6 However, there are disadvantages of using topical lidocaine without sedation, such as patient discomfort, which can prove to be problematic as patients who are uncomfortable may be unable to remain still for the procedure. Subsequently, benzodiazepines and opioids were administered to patients to facilitate better passing of the endoscope, decrease patient discomfort and keep patient movement to a minimum.7 Benzodiazepines and opioids are beneficial as they help the pharyngeal muscles relax, which facilitates the passing of the endoscope into the esophagus.

Midazolam is the most commonly used benzodiazepine that acts as a sedative/hypnotic in endoscopic procedures, such as EGD. Midazolam has a relatively quick onset with its peak effect occurring within 3-5 minutes; however, the duration of action is 1-3 hours, which necessitates a longer recovery period compared with topical lidocaine and propofol.7 Additionally, there are significant adverse effects of midazolam, including respiratory depression, hypotension and paradoxical agitation.

The most commonly used opioids for sedation during endoscopic procedures are meperidine and fentanyl. Meperidine is an opioid used during EGD procedures as a narcotic analgesic with mild sedative properties; however, it has a slow onset as well as a long duration of action, which necessitates a longer recovery period. In fact, the time required for the peak effect of meperidine is almost 10 minutes and the duration of action is approximately 2-3 hours.7 Meperidine also has adverse effects, which include respiratory depression, nausea, vomiting and potentially hypotension.7 Furthermore, when meperidine is concurrently administered with benzodiazepines, there are potential complications, including respiratory depression and oversedation. Fentanyl is a mild sedative and narcotic that has a rapid onset with a relatively short recovery time. In fact, many endoscopy centers prefer fentanyl over meperidine for outpatient endoscopic procedures. The peak effect of fentanyl is 5-8 minutes and the duration of action is approximately 1 hour.7 However, a significant adverse effect is respiratory depression.

Although EGD procedures can be performed with or without sedation, propofol, a hypnotic/amnestic agent, has become increasingly popular as the sedative of choice for endoscopic procedures because of its rapid recovery time, which is not seen with other sedatives, such as benzodiazepines.8 The advantages of using propofol are the rapid onset, with arm-to-brain circulation time being approximately 40 seconds, and a short recovery period of approximately 5-15 minutes.9 Sedation with propofol has become a fundamental component of gastrointestinal endoscopy, as it provides excellent hypnotic sedation with a quick onset and short duration of action.10 However, "propofol induces respiratory depression in a dose-response fashion and it has a negative cardiac inotropic effect causing a decrease in cardiac output, systemic vascular resistance and arterial pressure."10^(p.103) Respiratory depression can require endotracheal intubation if the patient is unresponsive to supplemental oxygen and bag-mask ventilation. Although, there are great advantages of administering propofol for EGD procedures, the potential effects of oversedation with propofol include adverse physiological changes, such as a change in oxygen saturation level, cessation of spontaneous breathing (apnea) and variation in mean arterial pressure. These potential, adverse physiological responses from propofol administration warrant a closer look at studies that include an adjuvant, such as topical lidocaine, to propofol during EGD procedures to curtail the potential of oversedation.

A preliminary search of JBI Database of Systematic Reviews and Implementation Reports, Cochrane Database of Systematic Reviews, PROSPERO and MEDLINE revealed that there are no systematic reviews available that examine the effectiveness of topical lidocaine as an adjuvant to propofol for procedural sedation in patients undergoing EGD procedures. In 2006, Evans et al. published a systematic review, which concluded that topical lidocaine, when combined with intravenous sedation, such as midazolam or meperidine, during EGD procedures, is beneficial in terms of facilitating the endoscopy and the patients' ability to tolerate the procedure.11 However, the systematic review did not analyze the effects of topical lidocaine when used as an adjuvant to propofol. Since this systematic review was published in 2006, there have been several published randomized controlled trials (RCTs) using topical lidocaine as an adjunct to propofol for procedural sedation in EGD procedures.

Inclusion criteria

Types of participants

The systematic review will consider studies that include adult patients and American Society of Anesthesiologists Physical Status Classification of I-IV,12 who receive topical lidocaine as an adjuvant to intravenous propofol for procedural sedation when undergoing an EGD. It will also include studies in which patients have undergone elective EGD procedures in various hospitals, ambulatory surgical centers and gastroenterology clinics throughout the world.

Studies containing the use of opioids and benzodiazepines in combination with topical lidocaine and propofol as an intervention will be excluded.

Types of intervention

The review will consider studies that evaluate the effectiveness of all forms of topical lidocaine as an adjuvant to intravenous propofol for procedural sedation versus intravenous propofol administered without any form of topical lidocaine in patients undergoing EGD procedures.

Outcomes

The review will consider studies that measure oxygen saturation level and mean arterial pressure, as well as the rate of intubation due to failed response to supplemental oxygenation when topical lidocaine is used as an adjuvant to intravenous propofol compared with intravenous propofol used alone for procedural sedation in patients undergoing EGD procedures.

Types of studies

The quantitative component of the review will consider both experimental and epidemiological study designs, including RCTs, non-RCTs, quasi-experimental studies, before and after studies, prospective and retrospective cohort studies, case-control studies and analytical cross-sectional studies.

Search strategy

The search strategy aims to find both published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search of MEDLINE and CINAHL will be undertaken followed by analysis of the text words contained in the title and abstract and the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken across all included databases. Third, the reference list of all identified reports and articles will be searched for additional studies. Studies published in English as well as those that can be translated into English by the author will be considered for inclusion in this review. Studies published after 1977 (when clinical trials of propofol began) will be considered for inclusion in this review.

The databases to be searched include:

CINAHL

EMBASE

Ovid MEDLINE

Scopus

TRIP

Web of Science

The search for unpublished studies will include:

Google Scholar

Theses and dissertations

Grey literature

ProQuest

http://www.clinicaltrial.gov

Initial keywords to be used will be: Propofol, Diprivan, Lidocaine, Xylocaine, Endoscopy, EGD, Esophagogastroduodenoscopy, Gastroscopy, Upper gastrointestinal endoscopy.

Assessment of methodological quality

Studies selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion or with a third reviewer.

Data extraction

Quantitative data will be extracted from studies included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives. Data will be extracted independently by two reviewers before conferring and a third reviewer will be used if there is any disagreement. The authors of primary studies will be contacted for any missing or unclear data.

Data synthesis

Quantitative data from studies examining topical lidocaine as an adjuvant to propofol for procedural sedation in patients undergoing EGD procedures will, wherever possible, be pooled in statistical meta-analysis using JBI-MAStARI. All results will be subject to double data entry. Effect sizes expressed as odds ratio for categorical data (intubation) and weighted mean differences for continuous data (oxygen saturation levels and mean arterial pressure) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard [chi]² and also explored using subgroup analyses based on the different study designs included in this review. Where statistical pooling is not possible, the findings will be presented in narrative form, including tables and figures to aid in data presentation, wherever appropriate.

Acknowledgements

The reviewers would like to express their gratitude for the support of the Louisiana Center for Evidence-based Nursing at LSUHSC-NO School of Nursing: A Joanna Briggs Institute Centre of Excellence. This review contributes to the Doctor of Nursing Practice degree award for Zachary Parish.

Appendix I: Appraisal instruments

Appendix II: Data extraction instruments

References