Sedation-Related C o mplic at i o n s i n G a s t ro i n t e s t i n a l E n d o s c o p y John J. Vargo II,
MD, MPH
KEYWORDS Cardiopulomonary unplanned events Pulse oximetry Capnography KEY POINTS Gastrointestinal endoscopy when undertaken by trained personnel after the appropriate preprocedural evaluation and in the right setting is a safe experience. However, clinicians should not be complacent in their lexicon when it comes to improving the safety of patients through further advances in the science of sedation and the lifetime journey of learning undertaken by gastrointestinal endoscopists. Significant challenges still exist in further quantifying the sedation risks to patients, optimizing physiologic monitoring, and sublimating the pharmacoeconomic and regulatory embroglios that limit the scope of practice and the quality of service delivered to patients.
“The real voyage of discovery consists not in seeking new landscapes, but in having new eyes.” —Marcel Proust INTRODUCTION
Defining the risk of procedural sedation for gastrointestinal endoscopic procedures remains a vexing challenge. The definitions as to what constitutes a cardiopulmonary unplanned event (CUE) are beginning to take focus but the existing literature is an amalgam of various definitions and subjective outcomes, which provides a challenge to patient, practitioner, and researcher. The incidence of CUEs associated with gastrointestinal endoscopy is low. The rate of CUEs varies in the literature from 1 in 170 to 1 in 10,000.1–3 QUANTIFYING RISK OF SEDATION-RELATED UNPLANNED EVENTS
Early survey studies, such as that by Arrowsmith and colleagues,4 culled data from more than 21,011 procedures and found the risks for serious unplanned events and death to be 5.4 and 0.3 per 1000 procedures, respectively. The most commonly
Department of Gastroenterology and Hepatology, Digestive Disease Institute, Cleveland Clinic, 9500 Euclid Avenue Desk A30, Cleveland, OH 44195, USA E-mail address: [email protected] Gastrointest Endoscopy Clin N Am 25 (2015) 147–158 http://dx.doi.org/10.1016/j.giec.2014.09.009 giendo.theclinics.com 1052-5157/15/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved.
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reported unplanned events were CUEs, which made up 40% of the reported events. By the very nature of its survey design, issues regarding ascertainment and recall bias could work in concert to underestimate the incidence of CUEs. Ganji and colleagues5 used the outcomes data from a large hospital system in a case-control fashion to ascertain cardiovascular complications associated with endoscopic procedures. In this study, CUEs were defined as hypotension, chest pain or anginal equivalent, arrhythmia, or myocardial infarction occurring within 24 hours of endoscopy. Subjects were considered at risk for CUEs based on cardiac enzyme determinations, charges for cardiovascular medicines, and intensive care unit admission on the day of or after endoscopy. The rate of CUEs was 308 per 100,000 procedures. Independent CUE risk factors included male gender, the use of propofol, and the modified Goldman score. Perhaps the best studies laying the framework for the incidence and risk factors for CUEs are by Sharma and colleagues6 and Enestvedt and colleagues7 analyzing the Clinical Outcomes Research Initiative endoscopic database. This database garners information from a total of 74 sites in the United States including academic, community, Veterans Affairs, and health maintenance organizations. In the work by Sharma and colleagues, data on 324,737 unique procedures including upper endoscopy, colonoscopy, endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS) using moderate sedation were reviewed. Overall, CUEs were reported in 0.9% of the procedures. Risk factors for these events included patient age, ascending American Society of Anesthesiologists (ASA) physical classification, inpatient procedures, nonuniversity sites and Veterans Affairs medical centers, the use of supplemental oxygen, and involvement of a trainee. Using the same database but with 1,590,648 unique endoscopic procedures, Enestvedt and colleagues found that an immediate adverse event occurred in 0.35% of all endoscopic procedures. Again, an increasing ASA physical classification was associated with a higher prevalence and was proportionally highest in ERCPs. In this study, however, the procedure-associated adverse event was defined as the rate of any immediate adverse event that prompted an unplanned intervention. This could include other unplanned events that were not cardiopulmonary in cause. Of the 470 serious adverse events, 14.5% of these included cardiopulmonary resuscitation. Risk factors for CUEs based on a review of the literature are listed in Box 1.
Box 1 Risk factors for cardiopulmonary unplanned events based on literature review Age ASA physical classification Type of anesthesia Inpatient Setting (nonuniversity, Veterans Affairs) Supplemental oxygen Trainee involvement Pulmonary disease Cardiac disease Obesity
Sedation-Related Complications
A UNIVERSAL LEXICON FOR CARDIOPULMONARY UNPLANNED EVENTS
One of the challenges in this genre is the lack of standardized lexicon with a supporting attribution scheme and severity scale for CUEs. In 2009, a lexicon for endoscopic adverse events workshop was held.8,9 The goals of this workshop were to provide clear definitions for adverse events and define levels of severity including the minimum threshold at which an adverse event should be documented and thus be counted and reported. Additionally, an analysis of the main risk factors for adverse events was undertaken, and how to consider the attribution with delayed events. Table 1 lists the CUEs that in most cases would stem from the sedation regimen used during the endoscopic procedure. For all CUEs it is important to attest the timing of the event with the procedure. Occasionally, these events can occur preprocedurally, during the procedure, or immediately thereafter. It is rare for a cardiopulmonary event to occur more than 6 hours after the endoscopic procedure. In addition, an attribution context should be developed to determine whether the CUE is definitely, probably, possibly, or unlikely related to the endoscopic procedure. Three aspects of CUEs should be kept in mind. First, “minor” events, such as transient hypoxemia, may not be clinically significant in most contexts. However, the predictive value of even these minor events has yet to be rigorously tested in a prospective fashion or within the purview of a large database. For example, even a minor episode of hypoxemia in a patient receiving supplemental oxygen could indicate significant alveolar hypoventilation. Second, because more serious CUEs, such as an oxygen saturation value of less than 85%, are uncommon, extremely large and costly randomized controlled trials are necessary to detect differences in safety and effectiveness of monitoring devices and sedation regimens. Third, because serious CUEs are rare, there are no data to show a decreased risk for such events by using various physiologic monitoring devices or sedation regimens. Because most critical event analyses have found prolonged hypoxemia secondary to respiratory depression is the triggering event in most cases of morbidity and mortality, we use such events as hypoxemia, disordered respiration, and apnea as the surrogate markers for the risk of serious CUE occurrence. Table 1 Cardiopulmonary unplanned events Category
Event
Definition
Cardiovascular
Hypotension
Blood pressure 190/30 or increase in systolic blood pressure >20%
Hypertension Dysrhythmia Cardiopulmonary arrest Myocardial infarction Cerebral vascular event Pulmonary
Hypoxia Apnea/hypopnea Laryngospasm Bronchospasm Pneumonia Pneumonitis
SaO2
MD, MPH
KEYWORDS Cardiopulomonary unplanned events Pulse oximetry Capnography KEY POINTS Gastrointestinal endoscopy when undertaken by trained personnel after the appropriate preprocedural evaluation and in the right setting is a safe experience. However, clinicians should not be complacent in their lexicon when it comes to improving the safety of patients through further advances in the science of sedation and the lifetime journey of learning undertaken by gastrointestinal endoscopists. Significant challenges still exist in further quantifying the sedation risks to patients, optimizing physiologic monitoring, and sublimating the pharmacoeconomic and regulatory embroglios that limit the scope of practice and the quality of service delivered to patients.
“The real voyage of discovery consists not in seeking new landscapes, but in having new eyes.” —Marcel Proust INTRODUCTION
Defining the risk of procedural sedation for gastrointestinal endoscopic procedures remains a vexing challenge. The definitions as to what constitutes a cardiopulmonary unplanned event (CUE) are beginning to take focus but the existing literature is an amalgam of various definitions and subjective outcomes, which provides a challenge to patient, practitioner, and researcher. The incidence of CUEs associated with gastrointestinal endoscopy is low. The rate of CUEs varies in the literature from 1 in 170 to 1 in 10,000.1–3 QUANTIFYING RISK OF SEDATION-RELATED UNPLANNED EVENTS
Early survey studies, such as that by Arrowsmith and colleagues,4 culled data from more than 21,011 procedures and found the risks for serious unplanned events and death to be 5.4 and 0.3 per 1000 procedures, respectively. The most commonly
Department of Gastroenterology and Hepatology, Digestive Disease Institute, Cleveland Clinic, 9500 Euclid Avenue Desk A30, Cleveland, OH 44195, USA E-mail address: [email protected] Gastrointest Endoscopy Clin N Am 25 (2015) 147–158 http://dx.doi.org/10.1016/j.giec.2014.09.009 giendo.theclinics.com 1052-5157/15/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved.
148
Vargo II
reported unplanned events were CUEs, which made up 40% of the reported events. By the very nature of its survey design, issues regarding ascertainment and recall bias could work in concert to underestimate the incidence of CUEs. Ganji and colleagues5 used the outcomes data from a large hospital system in a case-control fashion to ascertain cardiovascular complications associated with endoscopic procedures. In this study, CUEs were defined as hypotension, chest pain or anginal equivalent, arrhythmia, or myocardial infarction occurring within 24 hours of endoscopy. Subjects were considered at risk for CUEs based on cardiac enzyme determinations, charges for cardiovascular medicines, and intensive care unit admission on the day of or after endoscopy. The rate of CUEs was 308 per 100,000 procedures. Independent CUE risk factors included male gender, the use of propofol, and the modified Goldman score. Perhaps the best studies laying the framework for the incidence and risk factors for CUEs are by Sharma and colleagues6 and Enestvedt and colleagues7 analyzing the Clinical Outcomes Research Initiative endoscopic database. This database garners information from a total of 74 sites in the United States including academic, community, Veterans Affairs, and health maintenance organizations. In the work by Sharma and colleagues, data on 324,737 unique procedures including upper endoscopy, colonoscopy, endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS) using moderate sedation were reviewed. Overall, CUEs were reported in 0.9% of the procedures. Risk factors for these events included patient age, ascending American Society of Anesthesiologists (ASA) physical classification, inpatient procedures, nonuniversity sites and Veterans Affairs medical centers, the use of supplemental oxygen, and involvement of a trainee. Using the same database but with 1,590,648 unique endoscopic procedures, Enestvedt and colleagues found that an immediate adverse event occurred in 0.35% of all endoscopic procedures. Again, an increasing ASA physical classification was associated with a higher prevalence and was proportionally highest in ERCPs. In this study, however, the procedure-associated adverse event was defined as the rate of any immediate adverse event that prompted an unplanned intervention. This could include other unplanned events that were not cardiopulmonary in cause. Of the 470 serious adverse events, 14.5% of these included cardiopulmonary resuscitation. Risk factors for CUEs based on a review of the literature are listed in Box 1.
Box 1 Risk factors for cardiopulmonary unplanned events based on literature review Age ASA physical classification Type of anesthesia Inpatient Setting (nonuniversity, Veterans Affairs) Supplemental oxygen Trainee involvement Pulmonary disease Cardiac disease Obesity
Sedation-Related Complications
A UNIVERSAL LEXICON FOR CARDIOPULMONARY UNPLANNED EVENTS
One of the challenges in this genre is the lack of standardized lexicon with a supporting attribution scheme and severity scale for CUEs. In 2009, a lexicon for endoscopic adverse events workshop was held.8,9 The goals of this workshop were to provide clear definitions for adverse events and define levels of severity including the minimum threshold at which an adverse event should be documented and thus be counted and reported. Additionally, an analysis of the main risk factors for adverse events was undertaken, and how to consider the attribution with delayed events. Table 1 lists the CUEs that in most cases would stem from the sedation regimen used during the endoscopic procedure. For all CUEs it is important to attest the timing of the event with the procedure. Occasionally, these events can occur preprocedurally, during the procedure, or immediately thereafter. It is rare for a cardiopulmonary event to occur more than 6 hours after the endoscopic procedure. In addition, an attribution context should be developed to determine whether the CUE is definitely, probably, possibly, or unlikely related to the endoscopic procedure. Three aspects of CUEs should be kept in mind. First, “minor” events, such as transient hypoxemia, may not be clinically significant in most contexts. However, the predictive value of even these minor events has yet to be rigorously tested in a prospective fashion or within the purview of a large database. For example, even a minor episode of hypoxemia in a patient receiving supplemental oxygen could indicate significant alveolar hypoventilation. Second, because more serious CUEs, such as an oxygen saturation value of less than 85%, are uncommon, extremely large and costly randomized controlled trials are necessary to detect differences in safety and effectiveness of monitoring devices and sedation regimens. Third, because serious CUEs are rare, there are no data to show a decreased risk for such events by using various physiologic monitoring devices or sedation regimens. Because most critical event analyses have found prolonged hypoxemia secondary to respiratory depression is the triggering event in most cases of morbidity and mortality, we use such events as hypoxemia, disordered respiration, and apnea as the surrogate markers for the risk of serious CUE occurrence. Table 1 Cardiopulmonary unplanned events Category
Event
Definition
Cardiovascular
Hypotension
Blood pressure 190/30 or increase in systolic blood pressure >20%
Hypertension Dysrhythmia Cardiopulmonary arrest Myocardial infarction Cerebral vascular event Pulmonary
Hypoxia Apnea/hypopnea Laryngospasm Bronchospasm Pneumonia Pneumonitis
SaO2
