Anesthesia Principles and Practice I: Lecture 4 - GI Disorders

Question 1

What is pulmonary aspiration?

Answer 1

Gastric contents travelling up esophagus and into the trachea/pulmonary tree

Can occur in 1 in every 2-3,000 anesthetics

Decreased lower esophageal sphincter (LES) tone

Prevention is key- cause of significant morbidity and mortality
Bronchospasm
Aspiration pneumonia (can be fatal)
Acute respiratory distress syndrome (ARDS)- fluid collection in lungs
Lung Abscess- may cause destruction of pulmonary tissue
Empyema- collections of pus in the pleural cavity

Can occur in 1 in every 2-3,000 anesthetics

Question 2

What are the consequences of pulmonary aspiration?

Answer 2

• Bronchospasm
• Aspiration pneumonia (can be fatal)
• Acute respiratory distress syndrome (ARDS)
• Lung abscess
• Empyema

These conditions can lead to significant morbidity and mortality.

Question 3

What factors increase aspiration risk?

Answer 3

• Urgency of surgery
• Presence of difficult airway
• Inadequate anesthetic depth
• Lithotomy position
• Increased intraabdominal pressure
• Insulin dependent diabetes mellitus
• History of esophagectomy
• Full stomach
• Autonomic neuropathy
• Pregnancy
• Severe illness
• Obesity

Most common during induction

Most common during induction.

Question 4

How can the risk of aspiration be reduced?

Answer 4

• Minimize intake ASA NPO Guidelines
  Fried/fatty foods/meat 8 hours or more
  Light meal, nonhuman milk/formula - 6 hrs
  Breast milk - 4 hours
  Clear liquids - 2 hours
• Increase gastric emptying
  Metoclopramide (Reglan) - antiemetic 10 mg
• Reduce gastric volume and acidity
  OG/NG tube
  Antacids - Sodium Citrate (Bicitra) 30 cc suspension
  H2 receptor antagonist Famotidine (Pepcid)
  Proton pump inhibitor Pantoprazole (Protonix)

Following ASA NPO guidelines is key for aspiration prevention.

Question 5

What are GLP-1 receptor agonists used for?

Answer 5

• To treat Type 2 Diabetes
• To reduce cardiovascular risk
• To lose weight

Common drug names
Things that end in –tide
Dulaglutide (Trulicity®), Exenatide (Bydureon® or Byetta®), Liraglutide (Saxenda® or Victoza®),Lixisenatide (Adlyxin®), Semaglutide (Ozempic®, Wegovy®, Rybelsus®)

These medications can cause adverse GI effects like nausea and delayed gastric emptying.

Question 6

What the problem with GLP-1 receptor agonists?

Answer 6

These meds cause adverse GI effects like nausea, vomiting, and delayed gastric emptying ↑risk of aspiration.

Adverse GI symptoms like nausea, vomiting, dyspepsia, abdominal distention in patients on GLP-1 drugs = ↑gastric contents

Question 7

What should be done prior to procedure and on the day of surgery for patients taking GLP-1?

Answer 7

• Prior to Procedure
  For those taking a dose daily
  Hold GLP-1 on day of surgery

For those on weekly dosing
Hold for a week prior to surgery

• Day of Procedure
  If patient presents with severe nausea, vomiting, retching, abdominal bloating, or abdominal pain- consider delaying elective surgery
  Discuss risks of regurgitation and aspiration with surgeon and patient

No symptoms and GLP-1 held as advised? Proceed as normal

No symptoms but GLP-1 not held as advised?
Consider evaluating with gastric ultrasound, if empty proceed per usual.
If full, inconclusive, or not possible consider delaying or treat patient as “full stomach”
Discuss risks or regurgitation and aspiration with patient and surgeon

Proceed based on findings from gastric ultrasound.

Question 8

Who gets a Rapid Sequence Induction and Intubation (RSII)?

Answer 8

• Patients with Full Stomach
  Patients having emergency surgery
  Patients that have sustained trauma*
  Patients who do not meet ASA NPO guidelines
• Patients with GI Pathology
  Gastroparesis (d/t diabetic neuropathy or GLP-1 agonists)
  Small Bowel Obstruction
  Gastric Outlet Obstruction
  Esophageal stricture
  Achalasia
  GERD
• Patients with Increased Intraabdominal Pressure
  Morbid Obesity
  Ascites
  Pregnancy after 20 weeks

Question 9

What is the cricoid pressure debate?

Answer 9

Mixed research on efficacy of cricoid pressure

In most situations it is not harmful, and may be beneficial
Avoid in cervical spine trauma

Can make laryngoscopy more difficult

10 Newtons (2.5 lbs) of pressure in the awake patient leads to 30 Newtons (7.5 lbs) after LOC

Cricoid cartilage is signet ring

Pediatric and Neonatal patients may vagal
Consider atropine pretreatment

Several studies have shown decreased gastric insufflation if mask ventilation is required

In most situations, it is not harmful and may be beneficial but should be avoided in cervical spine trauma.

Question 10

What are nasogastric tubes used for?

Answer 10

Placed preoperatively in patients with small bowel obstruction, bowel obstruction, ileus, or other GI pathology

Put to suction BEFORE induction of anesthesia

DOES NOT, however, guarantee an empty stomach
May not be correctly placed, also will not remove particulate matter

Will make it tougher to get a seal if mask ventilation is required
If first pass at airway management after RSI is unsuccessful and patient is desaturating

Gives you an idea of where NOT to put the endotracheal tube

They do not guarantee an empty stomach and may complicate mask ventilation.

Question 11

What should be done if a patient starts regurgitating stomach contents after induction?

Answer 11

• Tip the head of the bed down (T-berg)
  Why? Allows gastric contents to drain away from the larynx
• Tilt patient’s head to the side and suction oropharynx
  Why? Allows for passive drainage
• Suction patient’s Trachea before giving a positive pressure breath
  Why? Hopefully prevents aspiration
• Release cricoid pressure if active vomiting occurs to prevent esophageal rupture

These actions help prevent aspiration and manage regurgitation.

Question 12

Combitube Tubes

Answer 12

Combitube – blind insertion airway device used in prehospital and emergency setting. Usually by those with limited DL experience.

Aspiration is most likely after induction agent and before inflation of low-pressure cuff on ET tube.

Question 13

Fluid Management for GI Surgery Considerations

Answer 13

Preop factors
Bowel prep, vomiting, diarrhea, bleeding, gastric compression

Significant evaporative losses for open cases- these are now rare

Bowel obstruction/pancreatitis may cause intravascular volume loss d/t inflammation and interstitial edema

Aspiration of ascites can lead to profound hypotension

Decreased venous return from abdominal insufflation

• THE ANSWER ISNT ALWAYS MORE!!!
  Excess intravascular fluid dilutes clotting factors

Increased extracellular fluid can lead to GI edema, decreased motility, even ileus.

Intestinal edema leads to increased chance of anastomotic leak

Increased extravascular fluid in lung tissue leads to worse oxygen exchange
Higher risk of post-op resp failure & pneumonia

Question 14

What is the Frank-Starling Law?

Answer 14

Represents relationship between stroke volume and end-diastolic volume

Stroke volume will increase in response to increase in volume of blood, before contraction. to a point.

Stroke volume increases in response to increased blood volume, to a point.

Question 15

Esophagus Review

Answer 15

Lower esophageal sphincter (LES) forms the border between the stomach and the esophagus.

Upper esophageal sphincter (UES)- formed from the muscles of the inferior pharynx and upper esophagus

Esophagus passes through the diaphragm at T10

Question 16

Diseases of the Esophagus

Answer 16

Hiatal Hernia- stomach sliding up through diaphragm into chest cavity. Essentially a herniation of the stomach.

Gastroesophageal Reflux Disease- GERD

Achalasia- neuromuscular disorder of the esophagus
Dilated hypomotile esophagus and esophageal outflow obstruction

Esophageal diverticula

Question 17

What causes decreased LES tone?

Answer 17

Obesity
Smoking
Pregnancy
Hiatal Hernia

Question 18

Drugs that alter LES

Answer 18

Increases
Metoclopramide
Neostigmine
Edrophonium
Succinylcholine
Metoprolol

Decreases
Atropine
Glycopyrrolate
Opioids
Volatile Anesthetics
Thiopental
Propofol

Question 19

What is a hiatal hernia?

Answer 19

Herniation of part of the stomach into the thoracic cavity

Many are asymptomatic- underlies importance of LES

May cause heartburn, dysphagia, and chest pain

Symptomatic hernias may require surgery

Found in 30% of patients having upper GI radiographic examinations.

Question 20

Hiatal Hernia Risk Factors and Causes

Answer 20

Risk Factors
Increased Age
Obesity
Smoking

Cause?
Mostly Unknown
Trauma
Congenital factors
Coughing, straining
Pregnancy/delivery
Weight gain

Question 21

What are symptoms of gastroesophageal reflux disease (GERD)?

Answer 21

• Heartburn
• Regurgitation
• Dysphagia
• Chest pain
• Odynophagia (painful swallowing)
• Globus sensation (lump in the throat sensation)

Symptoms can significantly impact quality of life.

Question 22

What treatments are available for GERD?

Answer 22

• Antacids
  Calcium carbonate, etc.
• Surface agents and alginates
  Sucralfate- adheres to mucosal surface
  Sodium alginate- derived from seaweed, forms viscous gum
• H2 Receptor antagonists decrease secretions
  Famotidine (Pepcid)
  Cimetidine (Tagament)- removed from market for cancer concerns
  Ranitidine (Zantac)
  Tachyphylaxis (in 2-6 weeks) limits use
• Markedly increased risk of aspiration
• Proton Pump Inhibitors- irreversibly bind to inhibit hydrogen-potassium pump
  Omeprazole (Prilosec)
  Esomeprazole (Nexium)
  Best taken 30-60 min before first meal
  Greatest amount of H-K-ATPase present in parietal cells after prolonged fast
  More effective than H2 drugs
• Surgery- Nissen Fundoplication
  Not necessarily fun

Treatment options vary based on severity and patient needs.

Question 23

GERD Surgery

Answer 23

• Transoral incisionless fundoplication
  Rebuilds the LES
  Still questionable level of fun

Question 24

What differentiates aspiration pneumonitis from aspiration pneumonia?

Answer 24

• Aspiration pneumonitis: treatment is largely supportive; usually resolves in 48 hours
• Aspiration pneumonia: requires antibiotics; more severe and often unwitnessed

Aspiration pneumonitis occurs shortly after aspiration, while pneumonia may develop later.

Question 25

What causes increased risk of aspiration pneumonitis?

Answer 25

* Volume of at least 0.4 mL/kg of gastric contents aspirated ~30 ml for 70 kg patient pH of gastric contents <2.5 Particulate matter ## Footnote These factors increase the likelihood of severe lung injury.

Question 26

What is achalasia?

Answer 26

HUGE ASPIRATION RISK Rare neuromuscular disorder (1:100,000) with inadequate relaxation of the LES and dilated hypomotile esophagus... food can't get into stomach Dysphagia Pulmonary aspiration is common Pneumonia, lung abscess, bronchiectasis can occur Treatment options Endoscopic botulinum toxin injection Pneumatic dilation Lap Heller Myotomy Per oral endoscopic myotomy (POEM) RSI or awake intubation for all patients!!!!!!!! Huge Aspiration Risk!!!!! Consider NG placement before induction Like…imagine a giant balloon full of food that didn’t make it to the stomach sitting like an aspiration bomb in someone’s esophagus. ## Footnote It affects about 1 in 100,000 people and leads to difficulty swallowing.

Question 27

Esophagectomy

Answer 27

Curative or palliative for malignant lesions Lap/robotic options exist Transthoracic (Open) esophagectomy is a huge case 2 big Ivs +/- Central Line, thoracic epidural, Arterial Line Can also be done trans-hiatally High morbidity and mortality risk 25-38% chance of ARDS/ALI 50% mortality rate if ARDS develops

Question 28

Anesthetic considerations for esophagectomy

Answer 28

Patients are often malnourished (protein-calorie) Surveillance of Barrett’s esophagus has improved diagnosis Patients may be post-chemo/radiation Pancytopenia, dehydration, lung injury may be present Risk of Aspiration continues for life Common to have recurrent laryngeal nerve injury Thoracic epidural has shown lower pulmonary complications/earlier return of bowel function

Question 29

Stomach Overview

Answer 29

Gastric secretions Hydrochloric acid Produced at a rate of 50-100 ml/hr pH of 1-3.5 Cephalic phase- thought/taste/smell of food mediated by cholinergic/vagal mechanism Gastric phase- Due to chemical effects of food and distension of stomach Mediated by gastrin Enterochromaffin cells mobilize histamine  stimulated H2 Receptors on Parietal cells to secrete acid

Question 30

Gastritis

Answer 30

Inflammation of stomach lining Symptoms: Fullness/burning in upper stomach, pallor/sweating/feeling faint or short of breath, belching, vomiting Triggered by smoking, alcohol, coffee, soda, tea PPI, H2 blockers, misoprostol, and sucralfate may be used for treatment Major trauma with shock, sepsis, respiratory failure, hemorrhage, massive transfusion, burns, head injury, or multiorgan failure is associated with acute stress gastritis

Question 31

What increases gastric volumes?

Answer 31

Obesity Pregnancy Shock Trauma Pain

Question 32

Peptic Ulcer Disease (PUD)

Answer 32

Burning Epigastric pain worsened by fasting and improved with meal consumption May lead to bleeding, peritonitis, dehydration, perforation, and sepsis Elderly and Malnourished at risk for these side effects Helicobacter pylori- Nobel Prize won for linking to PUD Antibiotics and PPOI Previous treatment was gastrectomy Hematemesis- Vomiting blood Melena- darkening of stools from digested blood

Question 33

Causes of PUD

Answer 33

H pylori bacteria NSAIDS Stress Hypersecretory states (rare) Gastrinoma d/t duodenal or pancreatic neuroendocrine tumors AKA Zollinger-Ellison Syndrome

Question 34

Peptic Ulcer Disease Treatment

Answer 34

Antacids, H2 blockers, PPI Miosoprostol (Prostaglandin E1 analogue) can be used for NSAID induced ulcers Not for pregnant folks Endoscopy for bleeding Ulcers Hemostatic clips Thermal coagulation Epi injection Severe cases may require embolization in IR

Question 35

Esophageal Varices

Answer 35

Cirrhosis of liver  increase in portal pressure (portal hypertension) Varices form to decompress hypertensive portal vein Can cause hypovolemic shock in extreme cases Major cause of death in liver failure Hemodynamic instability d/t variceal bleeding may require intubation for airway protection

Question 36

What is the TIPS procedure?

Answer 36

Transjugular Intrahepatic Portosystemic Shunt Off loads high portal pressure with a channel between hepatic vein and intrahepatic branch of portal vein Stent allows blood to return to systemic circulation Absolute Contraindications Congestive Heart Failure- Can decompensate with autotransfusion from splanchnic circulation Severe Tricuspid Regurgitation Polycystic Liver Disease Unresolved Biliary Obstruction Sepsis ## Footnote It offloads high portal pressure in patients with portal hypertension.

Question 37

What is portal hypertension?

Answer 37

Increased pressure in the portal vein ## Footnote It can lead to the formation of varices and other complications.

Question 38

What are varices?

Answer 38

Dilated veins that form to decompress hypertensive portal vein

Question 39

What is a potential consequence of variceal bleeding?

Answer 39

Hypovolemic shock in extreme cases

Question 40

What does the TIPS procedure do?

Answer 40

Off loads high portal pressure with a channel between hepatic vein and intrahepatic branch of portal vein

Question 41

What is a significant absolute contraindication for the TIPS procedure?

Answer 41

Congestive Heart Failure

Question 42

What is Ulcerative Colitis (UC)?

Answer 42

Inflammatory Bowel Disease Mucosal disease involving rectum and colon Chance of hemorrhage/perforation Colits usually presents with diarrhea, colicky abdominal pain, urgency, and incontinence Treatment incudes glucocorticoids and 5-ASA compounds 23-45% of patient’s require removal of colon and rectum Ileoanal anastamosis May result in ostomy Elevated Cancer Risk

Question 43

What are common symptoms of Ulcerative Colitis?

Answer 43

* Diarrhea * Colicky abdominal pain * Urgency * Incontinence

Question 44

What is the treatment for Ulcerative Colitis?

Answer 44

Glucocorticoids and 5-ASA compounds

Question 45

What is the risk of cancer in Ulcerative Colitis patients?

Answer 45

Increased cancer risk

Question 46

What is Crohn’s disease?

Answer 46

Inflammatory Bowel Disease that can affect any part of GI tract

Question 47

What are common symptoms of Crohn’s disease?

Answer 47

* Abdominal pain * Spiking fever * Weight loss (fear of eating, anorexia, diarrhea) * May create fistula or cause obstruction * Risk of Cancer increased

Question 48

What is diverticulosis?

Answer 48

Small pouches (diverticula) in the lining of the colon that bulge outward through weak spots. May be symptomatic or asymptomatic Cause? Increased pressure Low Fiber, High Fat, and Red Meat Symptoms Mild Cramps Bloating Constipation Treatment: High Fiber Diet

Question 49

What are the symptoms of diverticulitis?

Answer 49

* Abdominal pain * Nausea and vomiting * Cramping and constipation

Question 50

What is Diverticulitis?

Answer 50

Develops when diverticula become inflamed or infected Inflammation usually mild Small perforations are walled off by pericolic fat and mesentery Poor containment can lead to free perforation and peritonitis Antibiotics and liquid diet may treat, but colon resection still may be needed

Question 51

What is a hallmark sign of bowel obstruction?

Answer 51

Dehydration from decreased ability to absorb fluid Hypotension, Reduced Urine Output, orthostatic hypotension Pneumoperitoneum is a sign of perforation Can be caused by mass effect of nearby tumor

Question 52

What are the types of bowel obstruction?

Answer 52

80% in small bowel (SBO) Mechanical or Functional Functional (ileus) Cessation of peristalsis * Mechanical Simple Blocked in one place Closed loop Blocked in 2 places Strangulated Bowel twist around itself endangering blood flow Incarcerated Necrotic Bowel

Question 53

What differentiates small bowel obstruction from large bowel obstruction?

Answer 53

Location and symptoms vary, with SBO often causing vomiting before constipation

Question 54

What is the management for bowel obstruction?

Answer 54

* Fluid therapy May have severe volume depletion, electrolyte abnormalities Aggressive hypokalemia may be present, r/o AKI as K supplementation should be done carefully in this situation * NPO diet * GI decompression with NG tube * Immediate surgery if compromised Ischemia, Necrosis, or Perforation Resection and reanastamosis Potential for diverting ileostomy or colostomy

Question 55

What are carcinoid tumors?

Answer 55

Tumors that typically secrete GI peptides and/or vasoactive substances Typically secrete GI peptides and/or vasoactive substances Can see hypotension and bronchoconstriction Flushes may be precipitated by stress, alcohol, exercise, certain foods, SSRIs and catecholamines Most patients overproduce serotonin, resulting in diarrhea

Question 56

What is a carcinoid crisis?

Answer 56

Manifests with flushing, diarrhea, abdominal pain, tachycardia, and can be fatal 5-HT3Serotonin receptor antagonists can control nausea/diarrhea and may help with flushing Ondansetron, tropisetron, alosetron Somatostatin analogues help prevent carcinoid crisis, as most tumors have these receptors Octreotide, lanreotide

Question 57

Anesthetic Management of Carcinoid

Answer 57

General Anesthesia is required Invasive arterial BP monitoring for rapid changes in hemodynamics Delayed awakening, may need admit to ICU Admin of octreotide preop and before manipulation of tumor Drugs that may provoke mediator release Succinylcholine, mivacurium, atracurium, epinephrine, norepinephrine, dopamine, isoproterenol, thiopental Drugs not known to release mediators Propofol, etomidate, vecuronium, cisatracurium, rocuronium, sufentanil, alfentanil, fentanyl, remifentanil Desflurane may be the better choice because of low rate of metabolism

Question 58

Acute Pancreatitis?

Answer 58

Pancreas contains numerous digestive enzymes or proteases Autodigestion is usually prevented by Packaging in precursor form Synthesis of protease inhibitors Low intrapancreatic concentration of calcium Loss of these produces enzyme activation, autodigestion, and subsequent acute pancreatitis. Gallstone and alcohol abuse are cause in 60-80%

Question 59

What are the hallmarks of acute pancreatitis?

Answer 59

Increased Serum amylase and lipase Unrelenting mid-epigastric pain radiating to back Nausea/vomiting at peak of pain Abdominal distention with ileus is common Low grade fever, tachycardia, hypotension are common Shock may result Obtundation and psychosis may reflet EtOH withdrawal Severe gallstone pancreatitis may require Endoscopic Retrograde Cholangiopancreatography (ERCP) for stone removal/stent etc. Aggressive Fluid admin to correct hypovolemia

Question 60

What may indicate severe gallstone pancreatitis?

Answer 60

Endoscopic Retrograde Cholangiopancreatography (ERCP) for stone removal

Question 61

Fill in the blank: The hallmark of bowel obstruction is _______.

Answer 61

dehydration from decreased ability to absorb fluid

Question 62

True or False: Mechanical bowel obstruction is caused by cessation of peristalsis.

Answer 62

False