First let us define moderate (conscious) versus deep sedation.

Moderate sedation (conscious sedation) is a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. ¹

Many endoscopy procedures are done under moderate sedation. Examples of procedures that require moderate sedation are EGD and Colonoscopies. Moderate sedation is usually administered by the endoscopist with the assistance of trained nursing personnel. Generally they use a combination of benzodiazepine and opioid such as midazolam with morphine, meperidine or fentanyl.

Deep sedation is a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained. ¹

Deep sedation is generally required for a number of complex procedures that are more invasive, usually involving stenting, biopsy or drainage. Examples of procedures requiring deep sedation include:

• ERCP

• ENDOVASCULAR ULTRASOUND

• DOUBLE BALLOON ENDOSCOPY

• FEEDING TUBE PLACEMENT

• GASTRODUODENAL STENTING

• INTERVENTIONAL PROCEDURES

So when is an anesthesiologist needed for administration of sedation for endoscopy? There are several issues at hand which have recently changed the role of the anesthesiologist in the GI suite. In 2007 the Ohio Board of nursing changed its laws regarding nurse administered sedation. Here in Ohio nurses can now only administer moderate (conscious) sedation. Nurses can no longer administer deep sedation. Cases requiring deep sedation require the presence of an anesthesiologist to administer the deep sedation. The Nursing Interpretive Guidelines now state that “The nurse should not engage in activities that are the practice of anesthesia care…Therefore should not administer medications to induce deep sedation and/or anesthesia” ²

There are several additional situations where the endoscopist may request an anesthesiologist for the administration of even moderate sedation. Examples include:

1. History of difficult sedation in the past

2. History of problems with anesthesia

3. Pregnancy

4. Morbid obesity

5. Delirium or dementia

6. Alcohol abuse

7. Chronic pain patients

8. Significant medical co-morbidities

Another reason for the increasing need to have an anesthesiologist present to perform deep sedation, is the ever increasing complexity of the endoscopy cases. Procedures have become more complex and instruments sophisticated. This leads to the need for more effective sedation and analgesia techniques and the need to leave the endoscopist free to concentrate on the procedure at hand. ³

ERCP is performed as a diagnostic and therapeutic tool for a variety of biliary and pancreatic problems. Risk factors for complications include sphincter of oddi dysfunction, difficult cannulation, precut sphincterotomy in inexperienced hands, failure to achieve drainage and percutaneous transhepatic biliary access. ⁴

Complications of ERCP include

• Hemorrhage (usually after sphincterotomy) 1.34%

• Perforation of viscus 0.6%

• Pancreatitis 3.4%

• Infection 1.44%

• Pneumothorax

• Gas embolism

Overall mortality is 0.33%. ⁵

Our patient experienced the complication of duodenal perforation and subsequent pneumomediastinum and bilateral pneumothoraces.

Perforation during endoscopic sphincterotomy is a well recognized complication. It is usually retroperitoneal. ⁶ Retroperitoneal perforation occurs due to extension of a sphincteroromy beyond the intramural portion of the biliary or pancreatic duct. Intraperitoneal perforation may occur due to perforation of the bowel wall by the endoscope. Our patient had both intraperitoneal and retroperitomeal air from a duodenal perforation. Risk of perforation is less than 1% of ERCPs and sphincterotomys. Perforation is more likely in patients with Billroth 2 anatomy, needle-knife sphincterotomy, and sphincter of oddi dysfunction. ⁴ The presence of juxtapapillary diverticulum has not been shown to increase risk of perforation. ^{6, 7, 8}

Pneumothorax and pneumomediastinum resulting from perforation after ERCP and sphincterotomy has been reported many times in the literature. ^{9,10,11,12,13,14,15,16,17} The extensive emphysema is thought to be due to excessive air insufflation during the procedure after the perforation has occurred. The retroperitoneum is divided by the anterior and posterior renal fascia into three compartments which are in communication. After duodenal perforation air enters the right anterior pararenal space and then can further travel inferiorly and communicate with the posterior pararenal compartment. The posterior pararenal compartment extends through the diaphragmatic hiatus and into the mediastinum. Thus air under pressure enters the retroperitoneum and travels into the mediastinum causing pneumothoraces and pneumomediastinum as well as subcutaneous emphysema. ⁹ The amount of air leakage may not reflect the size of the perforation as much as the extent and duration of manipulation performed after the perforation. ⁶

Duodenal perforation is best diagnosed by abdominal CT.¹⁸ The treatment of perforation depends on the clinical state of the patient. Conservative management is recommended for patients with minimal signs, normal white cell count and absence of fever. This involves treatment with antibiotics, nasogsatric suction and nothing by mouth. Surgical management with closure of the perforation and drainage of the retropetioneal space is recommended for patients with signs of sepsis, contrast leakage or evidence of collections. ¹⁹