Gastroenterological Endoscopy. Группа авторов

      10.2 General Considerations

      10.2.1 Cardiopulmonary and Sedation-Related Events

      A cornerstone for proper performance of endoscopy is that the selection, and the monitoring of sedation should commensurate with the planned procedure. Cardiopulmonary adverse events account for up to 50% of severe morbidity and mortality related to GI endoscopy.^3,4 These adverse events range from clinically insignificant oxygen desaturation to clinical dysrhythmias, oversedation, aspiration pneumonia, respiratory failure, myocardial infarction, and shock. Many of these adverse events are linked to inappropriate sedation levels considering the type of procedure and the status of the patient, but they may also be associated with other adverse events such as bleeding, sepsis, and perforation.

      Before undertaking moderate sedation (see Chapter 4), the patient’s medical and surgical history, baseline medications with a particular focus on antithrombotic agents, and drug allergies must be assessed. The American Society of Anesthesiologists (ASA) score is a useful predictor of procedural sedation risk. Other risk factors include age, type of anesthesia, inpatient status, emergency procedure, and trainee involvement. Patients should not temporarily discontinue their cardiovascular medications except for antithrombotic agents when high-risk bleeding procedure is performed (see

Table 10.1),⁵ and this decision should be undertaken with advice from other specialists (cardiology, neurology, etc.) in patients at high risk for thrombosis.

      Pharyngeal anesthesia is usually recommended when no or minimal sedation is administered. It should be used with caution or avoided in nonintubated patients with suspected gastric outlet obstruction or gastroparesis, and in the presence of active upper GI bleeding as it increases the risk of aspiration pneumonia.³ Pre-oxygenation of patients with ischemic cardiovascular disease, as well as administration of supplemental oxygen during the procedure to avoid ischemic events, is recommended. All patients must be monitored using pulse oximetry before, during, and after the examination and continued until full recovery. Managing and avoiding cardiopulmonary adverse events requires competency in basic life support, knowledge of the patient’s underlying medical status, and pharmacological properties of the drugs used and their reversal agents.

      10.2.2 Infection

      Although rare,⁶ infections can result from the transmission of microorganisms through the endoscope from one patient to another or (even more rarely) through reprocessed devices, from the translocation of bacteria from the endogenous digestive flora through a tear or perforation in the mucosa, from contamination of a sterile compartment by patient’s GI flora (i.e., typically during ERCP in the presence of obstructed ducts and inadequate drainage), or by the transmission of microorganisms from patients to personnel of the endoscopy unit (and vice versa).

      All reported cases of patient-to-patient transmitted infections were due to failure to properly follow multisociety guidelines for disinfecting and reprocessing flexible endoscopes,^7,8 first published in 2003. It must be noted, however, that this type of infection remains of major importance as recently illustrated when contamination of duodenoscopes not adequately designed to allow proper disinfection resulted in severe iatrogenic infections.⁹

      Regarding prevention of bacterial translocation during endoscopy, prophylactic antimicrobial regimens are recommended in cases of suspected incomplete biliary drainage, puncture of fluid collections or cysts, percutaneous endoscopic gastrostomy placement, and in patients with variceal bleeding. In some cases, prophylaxis entails single-dose administration before treatment, while in others it may need to be continued, such as in patients with inadequately drained bile ducts or those with variceal bleeding. New techniques involving transmural access, such as endoscopic ultrasound (EUS)-guided biliary drainage, peroral endoscopic myotomy (POEM), and gastric transmural therapy, also require antibiotic prophylaxis with or without continued treatment. Unfortunately, prospective evidence for these indications is lacking.

      The protection of endoscopy personnel from infection/contamination by patient body fluids should be instituted and followed according to institutional universal exposure educational guidelines and postexposure management.¹⁰

      10.3 Upper Gastrointestinal Endoscopy

      10.3.1 Diagnostic Upper Gastrointestinal Endoscopy

      Diagnostic upper GI endoscopy is usually considered to be a safe procedure, with overall complication and mortality rates at 0.13 and 0.004%, respectively.¹¹ Procedure-induced Mallory–Weiss tear occurs in < 0.5% of diagnostic endoscopies and is generally not associated with significant bleeding.¹² Bleeding after mucosal biopsy is rare in the absence of thrombocytopenia, coagulopathy, or portal hypertension. Biopsies can be safely performed in patients with a platelet count > 20,000/mm.^3,13 Perforation secondary to diagnostic upper GI endoscopy is extremely rare, with an estimated frequency of < 0.03%.³ Risk factors for perforation include endoscopist inexperience, presence of cervical osteophytes, Zenker’s diverticulum, pharyngeal pouches, and esophageal stricture. Eosinophilic esophagitis is a recognized risk for mucosal tearing and perforation during diagnostic procedures.^14,

      10.3.2 Therapeutic Upper Gastrointestinal Endoscopy

      Therapeutic upper GI endoscopy has dramatically increased over the last 10 years and is associated with a much higher rate (approximately 10 times) of adverse events than diagnostic procedures.¹⁵

      Stricture and Achalasia Dilation

      Dilation of esophageal strictures and achalasia pneumatic dilation are associated with specific complications including perforation, bleeding, and bronchial aspiration. Bronchial aspiration can be prevented by endotracheal intubation, which is recommended in patients with comorbidities, although it is also associated with specific adverse events.¹⁶ Perforation risk varies with indication and technique used. Up to 4% risk has been described for pneumatic dilation of achalasia.¹⁷ It can be reduced by starting with a balloon diameter of 30 mm and not dilating greater than 35 mm.¹⁷ With the advent of POEM, the use of pneumatic dilation is likely to decrease.¹⁸ The risk of perforation when dilating malignant and caustic strictures is twofold compared with benign (peptic) strictures.¹⁹ Complex strictures (defined as an asymmetry, < 12 mm in diameter, or endoscopically impassable) are also associated with increased rates of complications.¹⁹ Another established risk factor for perforation is the level of operator experience. The risk of perforation during dilation is four times higher for trainees who have performed fewer than 500 upper GI endoscopies.³ Most perforations occur at the first session of dilation.²⁰ Three separate studies failed to show that bougie dilators are safer than balloon dilators in patients with benign strictures.²¹

      Stent Insertion

      Self-expandable metal stent (SEMS) placement is a method for palliating malignant dysphagia and malignant tracheoesophageal fistula.^22,23 SEMS can also be used to close upper GI fistulas in benign conditions.^24,25 Unfortunately, complications are frequent (20–40%).²⁶ Thoracic or epigastric pain is common after SEMS placement but is usually transient. Acute perforation is rare unless prior dilation was required. The risk of late perforation and bleeding seems to be higher with larger stents, and particular caution should be taken when stenting the gastroesophageal junction where asymmetrical pressure against the esophageal wall may precipitate ulceration, perforation, and/or bleeding. The use of larger stents,