Endoscopy Practice and Sedation: Endoscopy Practice and Sedation: Before the Scope

0:00Welcome to Board Pearls. This is episode one of four of the Endoscopy Practice and Sedation chapter, in the Endoscopic Procedures module. This episode is everything that has to be right before the scope goes in. The first patient is a woman with diabetes booked for an elective procedure, and her case shows fasting by what the patient ate, who counts as a full stomach, pregnancy testing, what to do about a glucagon-like peptide one agonist, and why a sodium-glucose cotransporter two inhibitor can put a patient in intensive care. A man with melena on tirzepatide shows when none of that preparation is allowed to delay a procedure. The second patient is a woman on warfarin booked for a polyp resection, and her case shows the antithrombotic decision: the procedure's bleeding risk, the patient's clotting risk, holding and restarting warfarin, and why bridging has almost disappeared. A man on apixaban shows the direct oral anticoagulants. A man with a new coronary stent shows the antiplatelet drugs. And a woman bleeding on apixaban shows how each drug is reversed.

1:01Here's the first patient. A forty-four-year-old woman is booked for an elective esophagogastroduodenoscopy and colonoscopy with propofol for iron deficiency. She has type two diabetes and obesity and takes weekly semaglutide, increased three weeks ago, since when she's had nausea and early fullness. She also takes empagliflozin and metformin. Her last menstrual period was five weeks ago. Her pre-procedure call is today, a week ahead.

1:29Her call has four things to settle a week ahead: her fasting, a possible pregnancy, her semaglutide, and her empagliflozin. Fasting comes first, because it reduces the gastric volume and acidity that drive aspiration during sedation. The American Society of Anesthesiologists guideline applies at every sedation depth and is captured in the two-four-six-eight pattern: clear liquids, meaning water, black coffee or tea, clear juices, and sports drinks, up to two hours before; breast milk up to four; infant formula and a light meal, such as toast or plain crackers, up to six; and a fatty or heavy meal up to eight. Clear liquids empty within one to two hours, while fat slows emptying through cholecystokinin-mediated relaxation of the antrum, which is why a fatty meal needs the longest window. Allowing clear liquids up to two hours prevents the dehydration and discomfort of a long fast without adding aspiration risk. So toast four hours before an elective procedure means a delay.

2:30For some patients, the clock doesn't settle the question. Gastroparesis, achalasia, gastric outlet obstruction, retained gastric content on a glucagon-like peptide one agonist, and pregnancy after the first trimester all delay gastric emptying enough that even a compliant fast can leave significant content in the stomach. Those patients are managed as a full stomach, with rapid sequence induction and a cuffed endotracheal tube when deep sedation is needed, or with a delayed procedure when the urgency allows.

2:58Her late period means a pregnancy test, because pregnancy changes the plan. Testing women of reproductive age before elective endoscopy is policy at most academic centers. Procedures that use radiation, such as endoscopic retrograde cholangiopancreatography, ERCP, the sedation agents, and the decision to proceed can all change with pregnancy; benzodiazepines and propofol haven't been shown to be teratogenic at sedation doses, but the evidence is incomplete. A urine human chorionic gonadotropin test is enough, with a serum quantitative test for ambiguous results. Hers is negative on the morning of the procedure. Pregnancy isn't an absolute contraindication to a necessary endoscopy, but for an elective iron deficiency workup the timing would be reconsidered, and a therapeutic procedure brings fetal monitoring and obstetric coordination, as chapter thirty-five covers.

3:51Her semaglutide, with her new nausea and fullness, raises her aspiration risk. The glucagon-like peptide one, GLP-1, agonists, semaglutide, tirzepatide, which is a dual GLP-1 and glucose-dependent insulinotropic polypeptide agonist, liraglutide, and dulaglutide, delay gastric emptying through receptors on gastric smooth muscle and through central appetite effects. Gastric retention can last hours to days, so a patient who fasts normally can still have substantial content in the stomach. The October twenty twenty-four multi-society guidance replaced holding the drug in everyone with risk stratification. Elevated risk means active gastrointestinal symptoms such as nausea, distension, or fullness, the dose escalation phase, or weekly dosing, and she has all three.

4:43Her elevated risk sets her preparation. Elevated-risk patients take a clear liquid diet for at least twenty-four hours before the procedure while continuing the drug. Holding it, for one week with weekly agents or one day with daily agents, is a fallback when shared decision-making concludes it should be held. So she takes clear liquids for a day beforehand and keeps her semaglutide. A patient without elevated risk who arrives without having held the drug can have a gastric ultrasound to look for retained content, can be treated as a full stomach with rapid sequence induction, or can proceed cautiously by shared decision.

5:17That preparation never delays a procedure that can't wait. The guidance states that time-sensitive endoscopy, for bleeding or obstruction, isn't delayed for GLP-1 management, because the extra aspiration risk is smaller than the harm of delaying a necessary procedure. A seventy-one-year-old man on weekly tirzepatide has melena, a heart rate of one hundred fifteen, and a hemoglobin of seven point two, and he ate dinner four hours ago. He's intubated with rapid sequence induction and scoped.

5:46Her empagliflozin is the more dangerous of her drugs, because of what fasting does with it. The sodium-glucose cotransporter two, SGLT-2, inhibitors, empagliflozin, dapagliflozin, canagliflozin, and ertugliflozin, block glucose reabsorption in the proximal tubule. During a fast, the continued urinary glucose loss plus reduced intake shifts metabolism toward ketones without the high glucose that would normally signal a problem and trigger an alarm. The result is euglycemic diabetic ketoacidosis: a metabolic acidosis with raised ketones and a normal or only mildly raised glucose. Twenty-four hours of clear liquids plus a bowel preparation is exactly the setting for it.

6:33So her empagliflozin is held well before her procedure. The American Society for Gastrointestinal Endoscopy, ASGE, February twenty twenty-five position statement recommends holding SGLT-2 inhibitors for three to four days before elective endoscopy, long enough for the urinary glucose loss to resolve before the preparation starts, so she stops empagliflozin four days ahead. If a patient took it the night before, the options are rescheduling or a basic metabolic panel. An anion gap with a normal glucose means euglycemic diabetic ketoacidosis has to be evaluated, and it's treated with intravenous fluids, dextrose, and insulin. Both of her drugs restart once she's eating again.

7:15Preparation also means deciding what to do with blood thinners, and the second patient shows that decision. A sixty-eight-year-old woman takes warfarin for atrial fibrillation. She has hypertension and diabetes, no stroke or transient ischemic attack, a CHADS2 score of two, no valve disease, and no venous clots, and her international normalized ratio, INR, usually runs about two point five. She takes aspirin after a coronary stent six years ago. A computed tomography scan for anemia showed a twenty-five-millimeter ascending colon polyp, and she's booked for endoscopic mucosal resection.

7:50Her warfarin decision weighs two risks, as every antithrombotic decision does: the bleeding risk of the procedure and the thromboembolic risk of the patient. The ASGE classifies procedures by whether they produce a wound that exposes an artery or arteriole capable of significant bleeding. Low-bleeding-risk procedures are diagnostic upper endoscopy with biopsy, diagnostic colonoscopy with cold biopsy, endoscopic ultrasound without fine-needle aspiration, ERCP with stent exchange or removal, capsule endoscopy, diagnostic balloon-assisted enteroscopy, argon plasma coagulation, and Barrett ablation. That mechanism is why argon plasma coagulation and Barrett ablation are therapeutic yet low risk. High-bleeding-risk procedures are polypectomy of larger polyps, ERCP with sphincterotomy, endoscopic ultrasound-guided aspiration of cysts, ampullectomy, endoscopic mucosal resection, endoscopic submucosal dissection, percutaneous endoscopic gastrostomy, variceal therapy, cystgastrostomy, and pneumatic or large-diameter dilation. Her endoscopic mucosal resection is high risk. ERCP depends on the plan: a stent exchange is low risk, and a sphincterotomy is high.

9:08Against that sits her clotting risk, which is stratified by the consequences of an interruption. High thromboembolic risk is any mechanical mitral valve, a caged-ball or tilting-disc aortic valve, a stroke or transient ischemic attack within three months, a CHADS2 score of five or six, a CHA2DS2-VASc score above seven, rheumatic valve disease, a prior thromboembolism on warfarin, a venous thromboembolism within three months, or severe thrombophilia, meaning protein C, protein S, or antithrombin deficiency, or antiphospholipid antibodies. Moderate risk is a bileaflet mechanical aortic valve with one risk factor, such as atrial fibrillation, prior stroke or transient ischemic attack, hypertension, diabetes, heart failure, or age over seventy-five; a CHADS2 score of two to four without prior stroke; a CHA2DS2-VASc of five to six; a venous clot three to twelve months ago; recurrent venous clots; active cancer; or non-severe thrombophilia, such as heterozygous factor V Leiden.

10:10Low risk is uncomplicated nonvalvular atrial fibrillation, a venous clot more than twelve months ago, or a bileaflet aortic valve alone. The consequences differ across these groups by an order of magnitude: mechanical mitral valve thrombosis is essentially fatal, while a brief hold in uncomplicated atrial fibrillation barely changes the annual stroke risk. With a CHADS2 score of two and no prior stroke, she's moderate risk.

10:38Together, her two risks set her warfarin plan. For low-bleeding-risk procedures, warfarin is generally continued. For high-risk procedures like hers, it's held for five days, with an INR on the morning of the procedure below one point five. Five days is about two half-lives of factor two, prothrombin, whose half-life of about sixty hours is the longest of the vitamin K-dependent factors. The morning check matters because the early fall in the INR is driven by factor seven, with a half-life of four to six hours, which can make the INR look corrected while factor two is still recovering. Her INR is one point three that morning. At one point eight, she wouldn't proceed.

11:20She isn't bridged, because the trials showed bridging harms patients like her. Bridging with low-molecular-weight heparin during a warfarin hold was once standard but has narrowed sharply since twenty fifteen. A large randomized trial in atrial fibrillation found nearly identical rates of arterial thromboembolism with and without dalteparin bridging, but more than twice the major bleeding with bridging. A later trial extended this to mechanical valve and higher-risk atrial fibrillation patients, finding no bridging non-inferior for thromboembolism in the moderate-risk groups, with bleeding favoring no bridging. In lower-risk patients, events during a brief hold are so rare that bridging can't reduce them, while residual heparin around the procedure and the restart adds bleeding. So bridging is now reserved for high-risk patients only, such as a mechanical mitral valve, a stroke or venous clot within three months, a CHADS2 of five or six, or a prior clot on therapeutic warfarin. She isn't bridged, though with a mechanical mitral valve she would be.

12:20Her aspirin continues, and her warfarin restart is timed by hemostasis. Secondary-prevention aspirin is continued through endoscopic procedures, for reasons the stent case shows. Warfarin restarts the same day in patients at low thromboembolic risk and within twenty-four to forty-eight hours in most others, guided by confidence in hemostasis rather than an arbitrary interval, with daily INR checks guiding her back into range. She restarts the next day.

12:49Direct oral anticoagulants are simpler, because their half-lives are short and they need no INR. A fifty-nine-year-old man with a plastic biliary stent for a benign stricture takes apixaban for a pulmonary embolism nine months ago, which puts him at moderate risk, and his ERCP now includes a sphincterotomy. Direct oral anticoagulants have half-lives of eight to seventeen hours. Apixaban and rivaroxaban are held twenty-four to forty-eight hours before low-risk procedures and forty-eight to seventy-two hours before high-risk procedures, so he holds his for forty-eight to seventy-two hours.

13:26Dabigatran is different, because the kidney clears it. About eighty percent of dabigatran is cleared by the kidneys, so the same calendar hold leaves different drug levels depending on kidney function. Before high-risk procedures, it's held about two days at a creatinine clearance of fifty milliliters per minute or more and four days at thirty to fifty, and longer below thirty. Before low-risk procedures, it's held about one day at fifty or more and two days below fifty.

13:51None of these drugs is bridged, because the gap is short. A direct oral anticoagulant hold lasts only one to four days, depending on the drug and kidney function, so bridging has nothing to cover. Restart after a high-risk procedure follows confidence in hemostasis, usually at twenty-four to seventy-two hours, and it's a yes-or-no decision, because there's no assay to titrate against. He restarts at forty-eight hours. Patients with cirrhosis and a raised baseline INR need a separate approach, because their INR reflects liver dysfunction rather than anticoagulation, as chapter twenty-three covers.

14:29A fresh coronary stent is the hardest antithrombotic case, because the balance is so lopsided. A sixty-three-year-old man had a drug-eluting coronary stent placed four months ago after a myocardial infarction and takes aspirin and clopidogrel. A screening colonoscopy found a thirty-millimeter flat polyp in his transverse colon, and his referral asks whether he can stop clopidogrel next week. Stent thrombosis after an antiplatelet interruption carries forty to sixty percent mortality, while most procedural bleeding can be managed endoscopically. So elective procedures are deferred entirely for thirty days after a bare metal stent and six months after a drug-eluting stent, revised down from twelve months with newer stents, because the stent isn't yet covered by endothelium. His endoscopic mucosal resection waits, booked so that the whole clopidogrel hold falls after six months, with cardiology consulted.

15:24His hold, once he's past the window, follows the platelet. P2Y12 inhibitors are held five to seven days before high-risk procedures when feasible, with aspirin continued throughout. Clopidogrel and prasugrel are irreversible thienopyridines that bind for the life of the platelet, so inhibition recovers only as new platelets are made over seven to ten days, while ticagrelor is reversible and washes out in three to five days. Other antiplatelet drugs have their own holds: dipyridamole two to three days, cilostazol two, ticlopidine ten to fourteen, and vorapaxar, a protease-activated receptor one inhibitor, five to thirteen.

16:05His aspirin stays, because stopping it is the bigger risk. Secondary-prevention aspirin, after myocardial infarction, stroke, or established coronary disease, is continued through nearly all procedures. It adds only a few percentage points of bleeding at most, usually manageable at the scope, while stopping it exposes the patient to coronary events and stroke. If it is held for a high-risk procedure, it restarts the same day hemostasis is confirmed. Primary-prevention aspirin, without established cardiovascular disease, is generally stopped in patients with a significant history of gastrointestinal bleeding. If an urgent procedure can't wait in the early window, cangrelor, an intravenous P2Y12 inhibitor with a half-life of three to six minutes, can bridge: the patient switches from oral therapy to cangrelor, it's stopped for the procedure, and oral therapy restarts afterward.

16:57When a patient is already bleeding, the question becomes reversal, and the drug decides the agent. A seventy-seven-year-old woman on apixaban for atrial fibrillation and aspirin for primary prevention has hematemesis, a heart rate of one hundred twenty-five, a blood pressure of eighty-eight over fifty after two liters, a hemoglobin of six point eight, and her last dose four hours ago. Andexanet alfa was withdrawn from the United States market in December twenty twenty-five over thrombotic events, so four-factor prothrombin complex concentrate, 4F-PCC, is the practical agent for apixaban and rivaroxaban, which are highly protein bound and can't be removed by dialysis. She gets 4F-PCC with resuscitation and urgent endoscopy, as chapter nine covers, and her primary-prevention aspirin stops permanently.

17:48The other drugs have their own reversal. Warfarin in life-threatening bleeding is reversed with 4F-PCC, about fifty milliliters compared with one to two liters of plasma, plus intravenous vitamin K, five to ten milligrams, for a sustained effect. Dabigatran is reversed with idarucizumab, five grams intravenously, and it can also be removed by dialysis. Antiplatelet effect can't be reversed with a drug, and platelet transfusion helps little, because circulating drug binds the transfused platelets too, so bleeding on aspirin or clopidogrel is controlled at the scope.

18:23Here are the traps the boards set in preparation. Patients aren't kept nothing by mouth from midnight; clear liquids are allowed up to two hours before. A light meal and a fatty meal have different windows. Delayed gastric emptying means the clock can't be trusted. Women of reproductive age are tested for pregnancy, and pregnancy isn't an absolute contraindication. GLP-1 agonists aren't held in everyone; elevated-risk patients take twenty-four hours of clear liquids, and urgent endoscopy isn't delayed for them. And SGLT-2 inhibitors are held three to four days, because euglycemic diabetic ketoacidosis hides behind a normal glucose.

19:01For antithrombotics, the traps are these. The decision weighs both risks, not one. Endoscopic mucosal resection and large polypectomy are high bleeding risk, while argon plasma coagulation, Barrett ablation, and stent exchange are low. Not every ERCP carries the same risk. Uncomplicated atrial fibrillation is low thromboembolic risk, and a bileaflet aortic valve isn't a mechanical mitral valve. Warfarin continues for low-risk procedures, is held for five days for high-risk ones, and needs a morning INR. Moderate-risk patients and direct oral anticoagulants aren't bridged. Dabigatran holds lengthen as kidney function falls. Secondary-prevention aspirin isn't stopped. Elective procedures wait out the stent windows, and a P2Y12 inhibitor isn't stopped in that window without cardiology. And andexanet is no longer available, factor ten A inhibitors aren't dialyzable, warfarin reversal includes vitamin K, and platelets don't reverse antiplatelet drugs.

20:04So, start to finish. Allow clear liquids up to two hours before the procedure, breast milk up to four, formula or a light meal up to six, and a fatty meal up to eight. Manage gastroparesis, achalasia, gastric outlet obstruction, retained content on a GLP-1 agonist, and pregnancy after the first trimester as a full stomach, however long the fast. Check a urine pregnancy test in women of reproductive age. On a GLP-1 agonist, patients with symptoms, in dose escalation, or on weekly dosing take clear liquids for twenty-four hours and keep taking the drug, while endoscopy for bleeding or obstruction goes ahead with rapid sequence intubation. Stop SGLT-2 inhibitors three to four days before elective endoscopy, and if one was taken anyway, reschedule or check a metabolic panel.

20:57Weigh the procedure's bleeding risk against the patient's clotting risk. Continue warfarin for low-risk procedures, and for high-risk ones hold it five days, confirm an INR below one point five, bridge only high-risk patients, and restart within twenty-four to forty-eight hours once hemostasis is secure. Hold apixaban or rivaroxaban one to two days for low-risk and two to three for high-risk procedures, lengthen dabigatran holds as clearance falls, and never bridge a direct oral anticoagulant.

21:25Continue secondary-prevention aspirin, hold clopidogrel or prasugrel five to seven days and ticagrelor three to five, defer elective procedures thirty days after a bare metal stent and six months after a drug-eluting stent, and use cangrelor when urgency can't wait. Reverse warfarin with 4F-PCC plus vitamin K, dabigatran with idarucizumab, and factor ten A inhibitors with 4F-PCC, and control antiplatelet bleeding at the scope.

21:54Episode two is sedation: how deep, for whom, and with which drug.

22:01For 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 one of four of chapter twenty-eight, and I'll see you in the next one.