Designing safe procedural sedation: adopting a resilient culture

Introduction

While millions of patients receive sedation every day, high-profile cases have brought medical errors in sedation to the public's attention. Alleviating pain and anxiety is a key component of the care provided to hospitalized and ambulatory patients. While reassurance, distraction, and behavioral strategies may offer relief, pharmacologic interventions are often required, especially in acute care settings. Sedation in the operating room and increasingly outside the operating rooms has been a growing industry due to the increase in the volume and types of procedures outside the operating room, an increase in the demand for special conditions to produce better image and results (i.e., MRI and dentistry), and an increase in the complexity of cases due to an increase in survival rates with complex pathology.

Sedation for gastrointestinal endoscopy has revolutionized the diagnosis, treatment, and prognosis of gastrointestinal tract diseases. Worldwide, a growing number of endoscopies (of increasing complexity and duration) for gastroenterology are performed each year, of which a large part requires sedation or anesthesia. The goal of sedation is to guard the patient's safety, provide comfort, control behavior, and minimize its impact on normal physiology. The practice of (endoscopic) sedation requires a thorough understanding of preprocedural assessment and preparation, sedation pharmacology, practical airway training, monitoring, adverse event management, and postprocedural care. The purpose of sedation is to relieve the patient's discomfort and anxiety while simultaneously reducing disruptive movements so that an adequate examination may be performed. Patient safety needs to be ensured while procedural efficacy is maintained.

A clinical microsystem is a group of clinicians and staff working together with a shared clinical purpose to provide care for a population of patients. The clinical purpose and setting define the microsystem's essential components, which include the clinicians and support staff, information and technology, the specific care processes, and the behaviors required to provide care to its patients. Examples of clinical microsystems include a cardiovascular surgical care team, a community-based outpatient care center, neonatal intensive care, and a pediatric sedation service. The clinical microsystem provides a conceptual and practical framework for approaching organizational learning and delivery of safe sedation care. To understand the functioning of these healthcare microsystems, and to improve their perioperative patient safety, it is necessary to study the components that make up the system—humans, technologies, and their complex interactions. In healthcare, the premium placed on practitioner autonomy, the drive for productivity, and the economics of the system may lead to severe safety constraints and adverse medical events.

The focus on the actions of individuals, without addressing the underlying microsystem, as the sole cause of adverse events, inevitably results in continued system failures and the resultant injuries and deaths of patients. Strategies to make sedation care more resilient and even safer might include the adoption of reliability engineering principles; setting up robust near-miss reporting systems ; applying critical event analysis tools such as trigger tools and failure mode and effects analysis (FMEA) when adverse incidents occur ; wide adoption of simulation and sedation team training; adopting checklists ; deploying standardized medication—doses, concentration, sets, implementing robust handoff protocols, and patient identification checklists ; and adherence to safe sedation practice standards.

Adequate pain control and sedation ensures the patient's comfort and cooperation, can influence the procedure's success, and can affect future attitudes toward healthcare providers and medical care. This chapter will describe key developments in sedation safety, safety research, risk and reliability management approaches, the role of human factors, and organizational practice models.

Preprocedural assessment

Sedation preparation involves performing an adequate risk assessment and determining when to enlist the assistance of anesthesia professionals. This should be done congruently with other pre-endoscopic evaluations, such as the need for antibiotic prophylaxis and bleeding tendency. The person administering sedation needs to assess for a previous adverse reaction to sedatives, symptoms of obstructive sleep apnea, and a history of alcohol overuse or drug abuse. These risk factors are associated with sedation complications. The physical examination should focus on vital signs, mental status, and the presence of pathologic anatomic features associated with a greater risk of airway obstruction and sedation difficulties.

Several distinct examinations must be performed based on an initial medical and surgical history review: firstly, a general exam to identify any underlying undiagnosed pathology present, looking closely for any obvious cardiovascular, respiratory, or abdominal signs; secondly, a thorough airway examination to predict the difficulty of airway management; and thirdly, detailed investigations may be required depending on comorbidities, age, and the nature of the procedure. Finally, there are standardized and validated score cards or tools available that can be used to document the assessment findings effectively, which not only facilitates day-of procedural review but also allows for benchmarking and quality improvements.

There is a well documented large variability in the: (1) level of experience and the scope of practice of clinical providers administering sedation and/or general anesthesia, i.e., gastrointestinal specialists, endoscopy-trained nurses, nurse anesthetists, physician assistants, and anesthesiologists and each has to know their limitations; (2) drugs administered during the procedure (sedatives, pain killers, anesthetic drugs); (3) airway techniques used (there is an extensive range of devices available for airway management requiring different levels of skills); (4) level of monitoring (including cardiovascular and respiratory monitoring); (5) duration and difficulty level of the procedure; (6) depth of sedation/anesthesia; (7) hospital (major teaching hospital vs. rural hospital) and the number of procedures performed, and (8) patients, each with their risk factors (e.g., obesity, hypoventilation, obstructive sleep apnea).

Preprocedural airway assessment

This section will concentrate on how best to predict difficulties in maintaining adequate oxygenation either with face-mask ventilation or with advanced airway management during (gastrointestinal) endoscopic procedures under sedation, whereby the patient's ventilation should be continuously observed by clinical assessment and monitoring of oxygen saturation (measured by pulse oximetry), and ventilation (with end-tidal carbon dioxide through noninvasive waveform capnography).

Airway management remains one of the most important responsibilities of the clinician administering sedation. Complications can occur even during conscious sedation procedures. Prediction of a difficult airway allows a management plan to be developed, time for proper patient selection, and proper selection of equipment, devices and techniques and support from others.

Difficult airway management remains a significant cause of morbidity and mortality and is generally encountered during unexpected clinical conditions. It is usually defined as difficulties with either performing adequate bag-mask ventilation, problems with visualizing the glottis with a direct laryngoscope (failed laryngoscopy), or difficulties with the insertion of a supraglottic airway device or the endotracheal tube leading to challenges or even failed endotracheal intubation. Furthermore, even a good view of the glottis does not necessarily translate into easy control of the airway.

Correctly predicting difficulties during airway management (i.e., difficulties with a facemask, OPAs, NPAs, SADs, ETTs) contributes to safer airway management. Therefore, a preoperative assessment of every patient's airway is recommended. Many countries have produced their own guidelines for preoperative airway assessment, although there does not exist a specific overall recommendation about what exactly needs to be evaluated, nor what is the most optimal selection of metrics that provide an accurate identification for predictors of difficult airways. No single test has shown to be an accurate predictor of difficult airway management, and none of the current tests are both highly sensitive and highly specific. Yet there is a clear need for a more accurate, simple, and clinically applicable airway assessment tools for predicting difficulties. Several predictive scores for difficult airway use different anthropometric features as simple preprocedural bedside tests ; Honarmand 2014, ^, ( Table 10.3 ).

Other criteria that may cause a difficult airway are buck teeth, snoring/CPAP, oral infections, abscesses or tumors, posterior neck fat pad, cervical spine mobility, and loose or missing teeth. Patients with bushy beards can be difficult to manually ventilate via bag mask ventilation.

Combinations of these tests result in better prediction scores of anatomically difficult airways as reported by Wilson and El Ganzouri. Other factors can contribute to difficulties in airway management, i.e., obesity, protruding incisors, single canines. However, numerous studies have demonstrated the limited ability to reliably and accurately predict a difficult airway. Alessandri et al. showed the relationship between ultrasound assessment of the anterior soft tissues of the neck, difficult laryngoscopy, and difficult mask ventilation. Ultrasound neck screening provides quick, relatively easy, and accurate information, with diagnostic and therapeutic relevance. Longer skin-to-larynx distances appears predictive for both difficult mask ventilation and difficult laryngoscopy.

The prediction of airway difficulties remains a challenging task, and the results of all studies underline the importance of being constantly prepared for unexpected challenges. None of the airway screening tests seems to perform well alone, and different combinations are suggested to improve accuracy and higher predictability. The STOP-BANG acronym (for Snoring, Tiredness, Observed aPnea, hypertension, high Body mass index, Age, Neck circumference, and Gender) questionnaire is an instrumental screening tool and a good predictor for airway complications in patients with undiagnosed obstructive sleep apnea. The choice of assessment is ultimately at the discretion of the individual sedation provider. Even large cohort studies, including hundreds of thousands of patients in Denmark, showed that the accuracy of clinical prediction of a difficult airway is poor. However, the recommended preoperative airway assessment is the way forward using a combination of presurgery metrics. These researchers demonstrate an overall prevalence of difficult/impossible facemask ventilation of 1.1%, which may be particularly important in conscious sedation.

Routine physical evaluation of the airway is generally done by the healthcare professional responsible for the sedation. However, during the COVID-19 pandemic, to reduce unnecessary exposure of healthcare professionals, virtual airway assessment was done via remote telemedicine, as part of the preprocedural evaluation of the patient, providing a valid alternative to direct physical consultation. Simple tests are: Can you fit three fingers in your mouth when fully opened? Can you place your lower teeth in front of your upper teeth? Can you fit three fingers between your chin and your Adam's apple? Do you have any problems with neck movements? What is your neck circumference? These are some of the questions that can easily provide valuable information even from a remote distance.

It's key is to focus on unanticipated airway compromise and obstruction by preprocedural airway assessment and preparation. The inability to maintain an open airway and adequate oxygenation is one of the most feared complications during deep sedation, such as gastrointestinal endoscopic procedures, which can result in catastrophic outcomes, such as anoxic brain injury and death.

Levels of sedation

Procedural sedation is a drug-induced depression of consciousness. Depending on the level of sedation, patients will be able to respond purposefully to verbal or tactile stimuli and may lack memory. Although we may aim for a certain level of sedation, sedation is a continuum of consciousness states, ranging from near awake to deep sedation, and can be obtained by using a variety of drugs and administration routes.

The level of sedation required to perform the procedure successfully and with high patient satisfaction depends on several factors. The healthcare professionals consenting and providing sedation need to consider the level of the patient's anxiety, gender, age, pain tolerance, existing pain, bowel sensitivity, and the use of medication and illicit drugs. Procedural considerations may be the complexity of the procedure and the therapeutic maneuvers necessary to reach the optimal therapeutic result and also strongly depends on the endoscopist's technical expertise, patience, and speed. After considering all factors, it is essential to discuss the most suitable level of sedation and to bring these in line with the patient's expectations. The clinician providing sedation should not be distracted by other responsibilities and is responsible for safe sedation and monitoring.

Different definitions were used to describe varying sedation levels, and they may differ for patients in the ICU, ED, and general anesthesia. In anesthesia, the most commonly used definitions for sedation were originally developed by the ASA in 1999 and was last updated in 2019 ( Table 10.4 ).

Minimal and moderate sedation can still leave the patient with the ability to respond purposefully to actions and commands while cardiovascular and ventilation functions are still preserved. Deep and general sedation represents a continuum in which patients may require assistance with maintaining the airway or cardiovascular function or full ventilation support.

The Ramsay sedation scale was developed to promote adequate sedation in the intensive care unit (ICU), and it was slightly modified for anesthesia ( Table 10.5 ).

The Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale is directed at determining the degree of suppression of consciousness and is widely used in the anesthesia research literature for quantifying the hypnotic effects of drugs ( Table 10.6 ).

Healthcare professionals providing sedation need to recognize the different sedation levels and be alert to changes with deepening sedation levels and be able to rescue a patient in respiratory failure from a deep level of sedation or even unconsciousness. Deep sedation and general anesthesia should strictly be overseen by anesthesia specialists who can maintain adequate respiration and cardiovascular function.

Patient selection and screening

The selection of appropriate patients for minimal and moderate sedation is crucial to the safety and success of sedation. Minimal and moderate sedation can be provided by nonanesthetists depending on the healthcare professional training and competency levels and on local legal requirements.

Important criteria to consider in patients that will likely require anesthesia support include:

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  Younger than 18 years old

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  Gravidity

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  ASA class III of cardiac cause or higher

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  Advanced therapeutic endoscopy (e.g., ERCP, balloon dilatation)

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  Morbid obesity (BMI >35 kg/m ² )

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  Severe sleep apnea (based on clinical diagnosis)

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  Difficult airway

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  Previously experienced anesthesia issues

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  Allergy to propofol or soy oil

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  Interventions requiring (intermittent) deep sedation

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  Anticipated intolerance to standard sedatives and opioids

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  Chronic use of significant amounts of pain medication

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  Patients with previous high sedation needs

In 2014, Braunstein et al. developed a scoring system to risk-stratify patients for high sedation needs during gastroscopy and colonoscopy who could benefit from anesthesia support. Based on the patient's characteristics, a SCOPE score was established, which correlates well with the patient's estimated risk for high sedation needs ( Tables 10.9 and 10.10 ).