GI Flashcards
GI tract consitutes what percent of the human body mass
5%
main function of the GI tract
motility, digestion, absorption, excretion, and circulation
outermost to innermost layer of GI tract
serosa –> longitudinal muscle layer –> circular muscle layer –> submucosa –> mucosa
Kahoot Q
within the GI mucosa what are the layers innermost to outermost
Everyone loves me (epithelium. Lamina propria. Muscularis
serosa is a smooth membrane of thin connective tissue and cells that secrete what?
serous fluid to enclose the cavity and reduce friction between muscle movements
which muscle layer contracts to shorten the length of the intenstinal segment
longitudinal muscle
which muscle layer contracts to decrease the diameter of the intestinal lumen
circular muscle layer
what two muscle layers work together to propagate gut motility
longitudinal and circular muscle layer
which plexus innervates the GI organs proximal to transverse colon
celiac plexus
which plexus innervates the descending colon and distal GI tract
inferior hyogastric plexus
kahoot Q
how can you block the celiac plexus (4)
transcural
intraoperative
endoscopic ultrasound guidedd
peritoneal lavage
which plexus lies between the smooth muscle muscle layers and regulates the smooth muscle
myenteric plexus
which plexus transmits information from the epithelium to the enteric and central nervous system
submucosal plexus
the mucosa is composed of a thin layer of smooth muscle called
muscularis mucosa, which functions to move the villa
the mucosa is composed of lamina propria which contain
blood vessels & nerve endings, immune and inflammatory cells
the mucosa is composed of an epithelium where the Gi contents are sensed and
enzymes are secreted, nutrients are absorbed, and waste is excreted
the extrinsic nervous system has which ANS components
autonomic nervous system
SNS and PSNS
SNS - inhibits and decreases GI motility
PSNS - excites and activates GI motility
the enteric nervous system is the independent nervous system that
controls motility, secretion, and blood flow
Kahoot Q
the enteric system is comprised of
myenteric plexus and submucosal plexus
myenteric plexus controls motility, which is carried out by
enteric neurons, interstital cells of Cajal (ICC cells, GI pacemakers), and smooth muscle cells
Respond to SNS and PSNS stimulation
Kahoot Q
the submucosal plexus controls
absorption, secretion, and mucosal blood flow
Respond to SNS and PSNS stimulation
upper GI endsocopy anesthesia challanges
sharing airway with an endoscopist
procedure performed outside the main OR
colonscopy anesthesia challanges
patient dehydration due to bowel prep and NPO cases
Kahoot Q
high-resolution manometry uses a pressure catheter along the length of the entire esophagus and is used to diagnosis what
motility disorders
GI series with ingested barium assess what
swallowing function and GI transit
Gastric emptying study requires a 4 hour fast and to consume a meal with radio tracer with frequent imaging over the next 1-2 hours. what can be diagnosed through this
used to diagnose gastroparesis
small intestine manometry measures contraction pressure and motility of the small intestine and evaluates contractions during which periods
fasting, during a meal, and post prandial
abnormal results are grouped into myopathic and/or neuropathic
lower GI series involves administration of what
barium enema.. it outlines the intestine to detect colon and rectal abnormalities
anatomical causes of esophageal disease
diverticula, hiatal hernia, and changes associated with chronic acid reflux
mechanical causes of esophageal disease
achalasia, esophageal spasms, and a hypertensive LES
causes of neurologic esophageal disease
stroke, vagatomy, or hormone deficiencies
dysphagia is _________ and classified into oropharyngeal or esophageal
difficulty swallowing
oropharyngeal dysphagia is common after
head and neck surgery
dysphagia is separated into esophageal dysmotility and mechanical esophageal dysphagia
esophageal dysmotility: symptoms with liquids and solids
mechanical esophageal dysphagia: symptoms with solid food only
what is GERD , and what are some symptoms
return of gastric contents into pharynx
Nausea, Heartburn, “lump in throat”
what is Achlasia
neuromuscular disorder of the esophagus consisting of an outflow obstruction due to inadequate LES tone and dilated hypomobile esophagus
achalasia is theorectically caused by
loss of ganglionic cells of the esophageal myenteric plexus
what happens with Achalasia that makes food unable to pass down into the stomach
esophageal dilation
symptoms of achalasia
dysphagia, regurgitation, heartburn, chest pain
what are the 3 classes of achalasia
Type 1: minimal esophageal pressure, responds well to myotomy
Type 2: entire esophagus pressurized; responds well to treatment, has best outcomes
Type 3: esophageal spasms w/premature contractions; has worst outcomes
Kahoot Q
Achalasia treatment
medication:
nonsurgical:
surgical:
nitrates & CCB to relax LES
endoscopic Botox Injection into LES
Pneumatic Dilation: most effective non-surgical
laproscopic Hellar Myotomy (surgical)
what is a POEM: peri-oral endoscopic myotomy?? and most common complication??
endoscopic division of LES muscle layers
40% develop a pneumothorax or pneumoperitoneum
achalasia patients are at increased risk of aspiration… what are some airway considerations
RSI or awake intubation
diffuse esophageal spasms usually occur in the _________ esophagus and likely due to ___________ ____________
distal esophagus; autonomic dysfunction
diffuse esophageal spasms are prevalent in which populations?
how is it diagnosed?
symptoms?
treatment?
elderly
esophagram
pain that mimicking angina
NTG, antidepressants, PD-I
esophageal diverticula are ______ in the wall of the esophagus
outpouchings
types of esophageal diverticula
Pharyngoesophageal (Zenker diverticulum): bad breath d/t food retention
Midesophageal: may be caused by old adhesions or inflamed lymph nodes
Epiphrenic supradiaphragmatic: pts may experience achalasia
ALL ASPIRATION RISKS. REMOVE PARTICLES AND RSI
Hiatal hernia
herniation of the stomach into the thoracic cavity- occurs through the esophageal hiatus in the diaphragm
may be asymptomatic; often assicated with GERD
c/b weakening anchors of gastroesophageal junction to the diaphragm
esophageal cancers presentation and survival rate
present with progressive dysphagia and weight loss
poor survival rate due to abundant lymphatics lead to lymph node metastasis
types of esophageal cancers
most adenocarcinomas located in lower esophagus
squamous cell carcinoma accounts for the rest
esophageal cancer treatment
esophagectomy
* high risk of recurrent laryngeal nerve injury, of which 40% resolve spontaneously
* post esophagectomy high of aspiration for life
chemo/radiation - pancytopenia and dehydration
GERD is incompetence of
gastro-esophageal junction leading to reflux
symptoms: heartburn, dysphagia, and mucosal injury
reflux contents of GERD include
HCL, pepsin, pancreatic enzyme, bile
bile reflux is associated with barrett metaplasia and adenocarcinoma
3 mechanisms of GE incompetence
- transient LES relaxation, elicited by gastric distention
- LES hypotension (normal -29 mmHg, GERD -13 mmHg)
- autonomic dysfunction
Kahoot Q
treatment for GERD
avoidance of trigger foods
antacids, H2 blockers, PPIs
sx: nissen fundoplication, toupet, LINX
preop interventions for GERD
- Cimetidine, Ranitidine -↓acid secretion & ↑pH
- PPI’s generally given the night before and the morning of
- Sodium Citrate - PO nonparticulate antacid (OB pts)
- Metoclopramide- gastrokinetic; often reserved for diabetics, obese, pregnant
- Aspiration precautions!
RSI indicated. Cricoid pressure has become controversial
what factors can increase intraop aspiration risk (12🫣)
Emergent surgery
Full Stomach
Difficult airway
Inadequate anesthesia depth
Lithotomy
Autonomic Neuropathy
Gastroparesis
DM
Pregnancy
↑ Intraabdominal pressure
Severe Illness
Morbid Obesity
The ______ is a J-shaped sac that serves as a reservoir for large volumes of food, mixes and breaks down food to form _________ , and slows emptying into the small intestine.
stomach; chyme
The motility of the stomach is controlled by
intrinsic and extrinsic neural regulation.
at the stomach, Parasympathetic stimulation to the vagus nerve increases
the number and force of contractions
at the stomach, sympathetic stimulation
inhibits these contractions via the splanchnic nerve
neurohormonal control in the stomach
gastrin & motilin increase the strength and frequency of contractions
gastric inhibitory peptide inhibits contractions
leading cause of non-variceal upper GI bleed
peptic ulcer disease may be associated with H.pylori
symptoms of Peptic ulcer disease
burning epigastric pain exacerbated w/fasting and improved w/meals
- 10% risk of perforation in those who do not receive treatment
- Perforation- sudden/severe epigastric pain c/b acidic secretions into the peritoneum
- Mortalityis d/t shock or perforation >48h
gastric outlet obstruction
Acute obstructions c/b edema & inflammation in the pyloric channel at the beginning of the duodenum
Pyloric obstruction sx: Recurrent vomiting, dehydration & hyperchloremic alkalosis
Gastric Outlet Obstruction treatment
NGT decompression, IV hydration; Normally resolves in 72h
Repetitive ulceration & scarring may lead to fixed-stenosis and chronic obstruction
causes of gastric ulcers
excessive NSAIDS, H. Pylori, ETOH
Kahoot Q
gastric ulcer therapy
Tx: Antacids, H2 blockers, PPIs, prostaglandin analogs, cytoprotective agents
H. Pylori- Triple therapy (2abx+ PPI) x 14 days
classification of GI ulcers
Zollinger Ellison Syndrome
Non-B cell islet tumor of the pancreas, causing gastrin hypersecretion
Gastrin stimulates gastric acid secretion. Gastric acid normally inhibits further gastrin release (neg feedback) This feedback loop is absent in ZE syndrome
Zollinger Ellison Syndrome symptoms and treatment
peptic ulcer dz, erosive esophagitis, diarrhea
PPIs and surgical resection of gastrinoma
Zollinger Ellison Syndrome anesthesia considerations
Pts have ↑ gastric fluid volume, possible electrolyte imbalances, & endocrine abnormalities.
Preop: Correct lytes,↑gastric pH w/meds, RSI
The major function of the small intestine is to circulate the contents and expose them to the mucosal wall to
maximize absorption of water, nutrients, and vitamins before entering the large intestine
Segmentation occurs when _____ nearby areas contract and thereby isolate a segment of _____
Segmentation allows the contents to remain in the intestine long enough for the essential substances to be ______ into the circulation.
Segmentation occurs when two nearby areas contract and thereby isolate a segment of intestine
Segmentation allows the contents to remain in the intestine long enough for the essential substances to be absorbed into the circulation.
It is controlled mainly by the enteric nervous system with modulation of motility by the extrinsic nervous system
reversible causes of small bowel dysmotility
mechanical obstruction such as hernias, malignancy, adhesions, and volvuluses
Bacterial overgrowth leading to alterations in absorptive function, ileus, electrolyte abnormalities, and critical illness
structural nonreversible causes of bowel dysmotility
scleroderma, connective tissue disorders, IBD
neuropathic nonreversible causes of bowel dysmotility
pseudo-obstruction in which the intrinsic and extrinsic nervous systems are altered and the intestines can only produce weak, uncoordinated contraction
This leads to bloating, nausea, vomiting, and abdominal pain
The large intestine acts as a reservoir
for waste and indigestible material before elimination and it extracts remaining electrolytes and water
Distention of the _____ will relax the _______ valve to allow intestinal contents to enter the colon
Distention of the ileum will relax the ileocecal valve to allow intestinal contents to enter the colon
Subsequent cecal distention will contract the ileocecal valve
The colon also exhibits ______ _______ complexes. these complexes serve to produce mass movements across the _____ ________
The colon also exhibits giant migrating complexes
Giant migrating complexes serve to produce mass movements across the large intestine
In the healthy state, these complexes occur approximately 6-10x a day
Colonic dysmotility manifests with two primary symptoms:
altered bowel habits and intermittent cramping
Rome II criteria defines IBS as having abdominal discomfort along with 2 of the following features:
- defecation relieves discomfort
- pain is assoc w/abnormal frequency (> 3x per day or < 3xper week)
- pain is associated with a change in the form of the stool
In IBD the contractions are suppressed due to
colonic wall compression by the inflamed mucosa, but the giant migrating complexes remain
There is an increased frequency of the giant migrating complexes and their pressure effect further compresses the inflamed mucosa, which can lead to hemorrhage, thick mucus secretion, and significant erosions
ulcerative colitis
Mucosal disease of rectum and part or all of the colon
In severe cases, the mucosa is hemorrhagic, edematous, ulcerated
Hemorrhage requiring ______ units blood in 24-48 hrs warrants _________
Hemorrhage requiring 6+ units blood in 24-48 hrs warrants surgical colectomy
Toxic megacolon is a complication triggered by e-lyte disturbances
About ½ cases resolve, ½ require colectomy
Colon perforation is a dangerous complication- mortality 15%
symptoms and labs of ulcerative colitis
diarrhea, rectal bleeding, crampy abdominal pain, N/V, fever, weight loss
may have ↑plts,↑erythrocyte sedimentation rate,↓H&H,↓albumin
Most common site of Crohn’s Disease
terminal ilium, usually presenting w/ileocolitis w/ RLQ pain & diarrhea
symptoms of Crohn’s Disease
Persistent inflammation gradually progresses to fibrous narrowing & stricture formation
Diarrhea decreases and is replaced by chronic bowel obstruction
Extensive inflammation leads to loss of absorptive surfaces, resulting in malabsorption & steatorrhea
Kahoot Q
Colonic disease may fistulize into stomach/duodenum, causing
fecal vomitus
1/3 Crohn’s pts have an additional symptoms s/a arthritis, dermatitis, renal calculi
IBD medical treatment
5-Acetylsalicylic acid (5-ASA)- mainstay for IBD *antibacterial & anti-inflammatory
PO/IV Glucorticoids during flares
Antibiotics: Rifaximin, Flagyl, Cipro
Purine analogues
Kahoot Q
surgical treatment of IBD
Last resort. Resected segment should be as conservative as possible.
Small intestine resection should be limited to <1/2 length.
>2/3 SI resection leads to “short bowel syndrome”, requiring TPN
Most carcinoid tumors originate
in any GI tissue/segment
Carcinoid Tumors secrete
Secrete peptides & vasoactive substances: gastrin, insulin, somatostatin, motilin, neurotensin, tachykinins, glucagon, serotonin, and other biological actives.
what is carcinoid syndrome
Lg amounts of serotonin & vasoactive substances reach the systemic circulation
Sx: flushing, diarrhea, HTN/HoTN, bronchoconstriction
* May acquire right heart endocardial fibrosis
The left heart is generally more protected as the lungs clear some of the vasoactive substances.
diagnosis, treatment for carcinoid tumors
Dx: urinary or plasma serotonin levels, CT/MRI
Tx: avoid serotonin triggers, control diarrhea, serotonin antagonists & somatostatin analogs
preop considerations for carcinoid tumor
Octreotide before surgery and before tumor manipulation to attenuate volatile hemodynamic changes
Kahoot Q
acute pancreatitis
inflammatory disorder of the pancreas
incidence has increased 10-fold likely due to ETOH and better diagnostics
autodigesion is normally prevented by
proteases packaged in precursor form
protease inhibitors
low intra-pancreatic calcium, which decreases trypsin activity
failure of any of these mechanisms can trigger pancreatitis
gallstones and ETOH abuse associated with acute pancreatitis
gall stones obstruct the ampulla of Vater, causing pancreatic ductal HTN
pancreatitis is also seen in immunodeficiency syndrome, hyperparathyroidism, and hypercalcemia
symptoms and labs of acute pancreatitis
excrutiating epigastric pain that radiates to back, N/V, abdominal distention, steatorrhea, ileus, fever, tahcycardia, and Hypotension
Hallmark Labs: increased serum amylase and lipase
complications of acute pancreatitis
complications such: as shock, ARDS, renal failure, necrotic pancreatic abscess
medical treatment for acute pancreatitis
aggressive IVF, NPO to rest pancreas, enteral feeding > TPN, opioids
TPN associated with higher infectious complications
interventional treatment for acute pancreatitis
ERCP - fluroscopic examinatino of biliary and pancreatic ducts
*stone removal, stent placement, sphincterotoy, hemostasis
which is more common
upper or lower GI bleed
upper GIB
blood loss greater than what will lead to hypotension and tachycardia
> 25%
what does orthostatic hypotension indicate
HCT< 30%
melena indicates that the bleed is above the
cecum (where small intestine meets the colon)
what BUN levels are associated with GI bleeding
BUN > 40 mg/dL due to absorbed nitrogen into bloodstream
treatment for GI bleeding
EGD is diagnositc/therapeutic procedure of choice
ulcer ligation
ligation of bleeding varices
mecanichal balloon tamponade is the last resort for uncontrolled variceal bleeding
causes of lower GI bleed
diverticulosis, tumors, colitis
generally occurs in the elderly
which scope can be done unprepped
which scope is performed with prep
prep = bowel prep
sigmoidoscopy - unprepped preformed when hemodynamically stable
colonoscopy performed if pt can tolerate prep
persistent lower GI bleeding warrants
angiography and embolic therapy
adynamic ileus is characterized as
massive dilation of the colon without mechanical obstruction
*loss of peristalsis leads to distention of the colon
causes of adynamic ileus
electrolyte disorders, immonility, excessive narcotics, anticholinergics
treatment for adynamic ileus
restore electroylte balance, hydrate, mobilize, NG suction, enemas
neostigmine 2-2.5 mg over 5 minutes produces immediate results in 80-90%
bradycardia - give glycorpyrrolate
if an adynamic ileus is left untreated what could occur
ischemia, and peforation may occur
Inhibition of GI activity is directly proportional to the amount of
NE from SNS stimulation
higher anxiety = higher inhibition
volatile anesthetics depress the spontaneous, electrical, contractile, and propulsive activity in
the stomach, small intestine, colon
which part of the GI tract is first to recover postoperatively
small intestine - followed by stomach in approx 24 hours and then the colon (30-40 hrs postop)
T/F volatile agents, coupled with sympathetic nervous system hyperactivity associated with surgery can excite GI function and motility
false, it inhibits GI function and motility
Gut distention and nitrous oxide correlates with
pre-existing amount of gas in the bowel, duration of nitrous oxide administration, and concentration of nitrous
Kahoot Q
when should nitrous oxide be avoided
lengthy abdominal surgey or when the bowel is distended
is GI motility affected by NMBDs
no - only affects skeletal muscles
Neostigmine (AChE-I) will increase _______ activity and bowel _______ by increasing frequency and intensitiy of contractions
PSNS, bowel peristalsis
the cholinergic activity is partially offset by concurrent administration of
anticholinergic meds (glycopyrrolate or atrpoine) used to counteract the bradycardia assocaited with neostigmine
will sugammadex effect motility
no
opioids are known to cause reduced GI motility and constipation bc there is a high densitity of peripheral mu receptors in the
myenteric and submucosal plexuses
activation of mu-receptors in myenteric and submucosal plexus leads to
delayed gastric emptying and slower transit through the intestine
adverse events of opioids
nausea, anorexia, delayed digestion, abdominal pain, excessive straining during BMs, and incomplete evacuation
