Endoscopy Practice and Sedation: Endoscopy Practice and Sedation: Hardware and Harm

0:00Welcome to Board Pearls. This is episode four of four of the Endoscopy Practice and Sedation chapter, in the Endoscopic Procedures module. This episode is hardware, capsules, and the language of complications. The first patient is a man with a heart valve, old endocarditis, a knee replacement, and a defibrillator, and his case shows whether any of them calls for antibiotics, which procedures do and the principle that ties them together, and what electrosurgery can do to a defibrillator and a pacemaker. The second patient is a woman with Crohn disease, iron deficiency, and a pacemaker, and her case shows capsule endoscopy: who can have it, why retention is the main risk, what a patency capsule does, and what happens when a capsule doesn't come out. Her case then leads into how the American Society for Gastrointestinal Endoscopy, ASGE, lexicon grades an adverse event from mild to fatal.

0:51Here's the first patient. A seventy-three-year-old man is booked for colonoscopy with likely removal of a twenty-millimeter polyp. He has a bioprosthetic aortic valve placed after endocarditis eight years ago, a total knee replacement, and an implantable cardioverter-defibrillator, ICD, for ischemic cardiomyopathy. His referral asks for antibiotic cover because of the valve, the endocarditis, and the knee, and asks whether his ICD needs switching off.

1:19His referral asks for two things he doesn't need, starting with antibiotics. Prophylaxis isn't recommended for prosthetic joints, prosthetic heart valves alone, pacemakers, defibrillators, synthetic vascular grafts, or routine endoscopy in patients with a history of endocarditis. The two thousand seven American Heart Association guideline removed gastrointestinal procedures from its indications, because the absolute risk of endocarditis from the bacteremia of endoscopy is too low to justify routine antibiotics, and the brief bacteremia that does occur is clinically insignificant with intact immunity. The prosthesis itself doesn't change the indications for endoscopic prophylaxis. Giving antibiotics reflexively for any device is the most commonly tested misconception here, so his plan states that he gets none. Diagnostic upper endoscopy and colonoscopy without specific high-risk features don't need prophylaxis either.

2:14Antibiotics follow one principle instead: they're given when a procedure introduces bacteria into a closed space that can't drain itself. The clearest example is endoscopic retrograde cholangiopancreatography, ERCP, when biliary drainage is expected to be incomplete. That happens in primary sclerosing cholangitis, with multiple intrahepatic strictures that can't all be drained; in hilar strictures such as Klatskin tumors, where contrast may fill segments that won't be stented; in liver transplant patients with anastomotic strictures; and in complex post-surgical anatomy. Retained contrast or bile in undrained ducts becomes a closed nidus, colonized by enteric flora introduced during the procedure. So coverage targets enteric gram-negatives and enterococci, typically a fluoroquinolone plus metronidazole, or ampicillin-sulbactam, and it continues after the procedure while drainage stays incomplete.

3:07The same principle explains the needle. Endoscopic ultrasound, EUS, guided aspiration of a cystic lesion of the pancreas or mediastinum carries oral and skin flora into a previously sterile space with no drainage, and infection there is morbid, as an infected pancreatic cyst or mediastinitis. So it gets a dose before the procedure and three to five days of oral antibiotics after. Aspiration of a solid lesion, a lymph node, a mediastinal mass, or a solid pancreatic tumor doesn't, because the tract isn't a closed space, and the immune system clears the small inoculum.

3:44The remaining indications each have their own reason. Percutaneous endoscopic gastrostomy, PEG, or gastrojejunostomy placement gets one gram of intravenous cefazolin thirty minutes before, covering skin flora at the puncture site and the oral flora the tube drags through the mouth and esophagus. One dose is enough, because the tract heals over the following days. Cirrhosis with acute upper gastrointestinal bleeding gets ceftriaxone one gram intravenously daily for the duration of the bleed, because hemorrhage and hypoperfusion disrupt the gut barrier and cirrhotic immune dysfunction lets bacteria seed the ascites or blood. That rule is driven by the patient's event rather than the procedure, so elective variceal banding without bleeding needs none. Peritoneal dialysis patients having lower endoscopy get ampicillin plus an aminoglycoside before the procedure to cover the peritoneal cavity. So a PEG after a stroke would earn him cefazolin, and an ERCP with undrained strictures would earn prophylaxis, in both cases because of the procedure, not his valve.

4:48His defibrillator is the second request, and it does need a plan, though not the one asked for. Electrosurgery interacts with cardiac devices through electromagnetic interference. With bipolar current, the current passes between two electrodes within the snare or coagulation device, which greatly reduces interference at the implanted device. With monopolar current, it passes through the patient's body to a return electrode, with a higher risk of pacemaker reset, ICD discharge, or interference with sensing. An ICD's detection algorithm can read electrosurgical interference as ventricular tachycardia or fibrillation and deliver an inappropriate shock.

5:27So, in coordination with cardiology, his ICD's arrhythmia detection is suspended during electrosurgery, either by placing a magnet, which inhibits anti-tachycardia therapies on most devices, or by formal interrogation and reprogramming. External defibrillator pads go on before the procedure as a backup. His pacing function isn't disabled; only the arrhythmia detection is suspended. Detection is restored immediately after the procedure, by someone who owns that step. So his ICD isn't switched off: its shock function is suspended and then restored.

6:00A pacemaker without a defibrillator is simpler, because it has no shock function for interference to trigger. Modern pacemakers tolerate the monopolar current of routine polypectomy without reprogramming, provided the return electrode, the grounding pad, is placed away from the heart and the device, typically on the lower back or thigh, so stray current doesn't cross the device. Routine reprogramming to an asynchronous mode isn't required and only adds complexity. Bipolar current keeps the current at the surgical site, with the pad placement as a backup margin. A pacemaker-dependent patient having monopolar electrosurgery in the cardiac field, such as in the esophagus, needs a backup pacing plan and cardiology input. Neither device needs antibiotics.

6:42The second patient's pacemaker matters for a different reason, because she needs a capsule that transmits by radio. A thirty-eight-year-old woman has ileal Crohn disease diagnosed six years ago and had an ileocecal resection three years ago. She now has iron deficiency anemia with a normal esophagogastroduodenoscopy and colonoscopy, and her team wants a capsule endoscopy. She takes ibuprofen most days for joint pain and has a pacemaker for heart block.

7:09She has suspected small bowel bleeding, which is what a capsule is for, but her history makes it risky. Capsule endoscopy uses a swallowed wireless camera that passes through the gut and transmits images of the small bowel that conventional endoscopy can't reach, and once it's swallowed, it can't be retrieved if it lodges before the colon. Her pacemaker isn't the problem. Pacemakers and ICDs were once absolute contraindications because of theoretical interference with the capsule's radiofrequency transmission, but modern platforms have been validated as safe with pacemakers and most ICDs, and current ASGE guidance doesn't list cardiac devices as absolute contraindications. Checking with the manufacturer remains prudent for older capsule platforms or unusual devices. Pregnancy is a relative contraindication, so elective small bowel evaluation is deferred. Patients with severe dysphagia or an esophageal stricture under ten millimeters can have the capsule delivered endoscopically into the duodenum.

8:09Her real risk is retention, defined as failure of the capsule to pass within two weeks of ingestion. Retention occurs in about one to two percent of patients with suspected obscure bleeding and no known stricture, but in five to thirteen percent of patients with Crohn disease, prior bowel surgery, enteropathy from nonsteroidal anti-inflammatory drugs, prior abdominal radiation, or known small bowel obstruction. A focal narrowing lets liquid and small particles pass but traps a rigid capsule measuring twenty-six by eleven millimeters. She has three of those risks, Crohn disease, an anastomosis, and daily ibuprofen, so she's high risk, and retention for her would mean enteroscopy or surgery to retrieve the capsule.

8:51She's protected by a test run first. A patency capsule is a self-dissolving dummy with a barium core and a lactose-and-barium body that dissolves over about thirty hours, releasing a small radiofrequency tag that can be tracked by an external scanner or seen on a plain film. It's swallowed before the diagnostic capsule. If it passes intact within thirty hours, the bowel is patent enough for the diagnostic capsule. If it doesn't pass, or passes partly dissolved, there's a stricture, so the diagnostic capsule is deferred, or delivered endoscopically with retrieval planned. Computed tomography, CT, or magnetic resonance enterography first is the alternative. Hers is still in her right lower quadrant at thirty hours, so her diagnostic capsule is deferred, and magnetic resonance enterography shows a short anastomotic stricture with active inflammation above it, explaining her anemia.

9:45Had a diagnostic capsule been retained, the next steps would follow from its location. Retention is evaluated with CT or magnetic resonance enterography, and the capsule is then retrieved by single-balloon, double-balloon, or push enteroscopy, depending on where it sits, or by surgery if endoscopic retrieval fails.

10:04A retained capsule would also be graded as an adverse event, and the ASGE lexicon grades events by the intensity of the intervention they required. A mild event aborts the procedure or prevents it from starting, or leads to a post-procedure medical consultation or an unplanned admission or longer stay of three nights or fewer, without transfusion or further intervention. A moderate event requires four to ten nights in hospital, one night in the intensive care unit, a transfusion, or repeat endoscopic or interventional radiology treatment. A severe event requires more than ten nights, more than one intensive care night, surgery, or results in permanent disability; in the twenty ten lexicon, interventional radiology treatment counts as moderate, not severe. A fatal event is a death within thirty days attributable to the procedure or its complications. So a retained capsule retrieved by balloon enteroscopy is a moderate event, and one needing surgery is severe.

11:00The same grades apply to other events, always by what they required. Post-polypectomy bleeding is mild if managed without transfusion, moderate if it needs transfusion or repeat endoscopy, such as a delayed bleed clipped at repeat colonoscopy, and severe if it needs surgery or prolonged intensive care; colonoscopy complications are covered in chapter thirty. Perforation is generally moderate or severe, because it almost always needs a prolonged stay or a surgical or endoscopic closure. Post-ERCP pancreatitis is mild with two to three extra days in hospital, moderate with four to ten, and severe beyond ten days or with organ failure or surgery; chapter twenty-nine covers it. An episode of apnea during sedation that aborts a colonoscopy is mild, as is one night of observation, while one night in intensive care is moderate.

11:51The lexicon also records two outcomes separately from severity. An incomplete procedure is one where the planned intervention couldn't be completed for any reason. A failure of intent is one where the procedure was completed but didn't achieve its clinical goal, such as a capsule whose battery dies before it reaches the colon. Her capsule, deferred for a planned clinical reason, is neither. Standardized grading allows benchmarking across units and operators, and it makes the risks quoted at consent better calibrated.

12:20Here are the traps the boards set in prophylaxis and devices. A prosthetic valve, prosthetic joint, vascular graft, pacemaker, defibrillator, or prior endocarditis doesn't call for antibiotics. Aspiration of a solid lesion and elective banding don't either. ERCP with incomplete drainage, aspiration of a cyst, PEG placement, cirrhosis with bleeding, and peritoneal dialysis before lower endoscopy do. Pacemakers aren't reprogrammed routinely, and the grounding pad goes away from the device. And an ICD has detection suspended during electrosurgery, pacing left on, and detection restored afterward.

12:59For capsules and adverse events, the traps are these. A modern pacemaker or ICD isn't a reason to cancel a capsule. A high-risk patient gets a patency capsule or enterography before the diagnostic capsule. Retention means the capsule hasn't passed within two weeks, and a patency capsule still present at thirty hours means a stricture. Patients who can't swallow the capsule can have it delivered endoscopically. Adverse events are graded by the intervention they needed, not their name. Interventional radiology treatment is moderate under the twenty ten lexicon, and a transfusion is never mild. And an incomplete procedure isn't the same as a failure of intent.

13:38So, start to finish. Give antibiotic prophylaxis only when a procedure introduces bacteria into a closed space: ERCP with expected incomplete drainage, continued afterward; cyst aspiration, with a dose before and three to five days after; PEG placement, with one gram of cefazolin; cirrhosis with gastrointestinal bleeding, with ceftriaxone one gram daily; and peritoneal dialysis before lower endoscopy. Pacemakers need only a return pad away from the device, while ICDs need detection suspended, external pads, pacing left on, and detection restored.

14:13Capsule retention, failure to pass within two weeks, rises to five to thirteen percent with Crohn disease, prior surgery, anti-inflammatory drug enteropathy, radiation, or obstruction, so use a patency capsule or enterography first, and retrieve a retained capsule by enteroscopy or surgery. Grade adverse events by what they required: mild up to three nights, moderate for four to ten nights, one intensive care night, a transfusion, or repeat endoscopic or radiology treatment, severe beyond that or with surgery or disability, and fatal within thirty days. Record incomplete procedures and failures of intent separately.

14:51That completes chapter twenty-eight. Chapter twenty-nine is ERCP and EUS procedures.

14:57For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode four of four of chapter twenty-eight, and I'll see you in the next one.