Small Intestine Flashcards
List 6 possible prokinetics and their brief MOA where known
Bethanecol - M3 muscarinic agonist
Erythromicin - motilin receptor agonist
Metaclopramide - D2 dopamine antagonist
Neostigmine - acetylecholinesterase inhibitor
Cisapride - 5HT4 agonist
Lidocaine - not well known
What % of horses undergoing sx for EFE demonstrated crib biting behavious according to van Bergan et al 2019 - vet surg
60% of 142 horses were crib biters
What is the most common direction of EFE
Almost all entrapments occur from LEFT TO RIGHT
What proportion of EFE cases had ileal involvement as per van bergan 2019 vet surg
74% of 142 horses had ileal involvement in their EFEs
Overall short term survival and survival of those recoverying from GA for EFE ex laps reported by van Bergan 2019 vet surg
Overall STS 48%
65% STS for those recovering from GA
High rate -26% - of intra-op PTS dt ileal involvelemtn or financial concerns
35% of recovering horses died or were euthanised prior to DC most commonly dt POR (70%)
Give 1 risk factor for non-survival prior to discharge and 1 for nonsurvival post discharge according to van Bergan 2019 Vet surg, following ex lap for EFE
Development of POR was associated with non survival in the short term
Performing R&A was assoc with worse long term survival (incr colic)
Which anastomosis type was associated with the highest rate of POR folowing ex lap for EFE reported by van Bergan 2019 Vet Surg
What POR rates were observed in the other anastomosis types and with decopression only
End-end jejunoileostomy had highest rate of POR (79%)
Vs 50% side-side JC and 40% end-end JJ and 20% for those undergoing decompression only
Why might the short term outcome of JI anasomoses be worse than for JJ or JC?
Which anatomosis type is reported to have the poorest long term outcome?
JI - usually performing as ileum is involved -thicker than jejunum anyway but especially so in dz, so inverting patterns can create significant infolding tissue cuff and decrease anastomotic size significantly
JC anastomoses are assoc with worse long term px generally.
Reported EFE recurrence rate by van Bergen 2019 Vet Surg
EFE recurred in 3% of survivors
Reported mortality rates with POR following colic sx
Upto 52%
Rate of POR reported following ex lap for small intestinal lesions by Boorman et al (2019 VS)
65% developed POR (defined as >2L reflux at any 1 time PO)
30% developed high volume POR (>20L in 24hr)
What did Boorman et al (2019 VS) conclude about age as a risk factor for POR following small intestinal surgery?
What were the risk factors for development of POR, high volume POR and nonsurvival
Age was not a risk factor for POR, high volume POR or nonsurvival
Risk Factors (multivariate)
1) POR - increased admission PVC and presence of NG reflux at adminssion
2) High volume POR - hyperglycaemia at admission, NG reflux at admission & peforming R&A
3) Non-survival - high volume POR and increased surgery duration
Blood supply to the ileum
Comes from the ileal artery - branch of the ileocolic artery (from cranial mesenteric)
Anastomoses with the terminal jejunal arteries
List 5 subjective and 6 objective measures to determine intestinal viability intra-op
Subjective:
- serosal colour,
- improvement in colour after correction of the strangulation,
- mesenteric arterial pulses,
- presence of constrictive rings
- intestinal motility.
Objective:
- fluorescein fluorescence post IV administration
- thermography
- surface oximetry (<20mmHHg)
- pulse oximetry
- Doppler ultrasonography
- intraluminal pressure measurement
Clinical Judgement likely the most important
Clinical grading scale of assessment of intestinal viability developed by Freeman 2001
What were the risk pre-op risk factors for requiring R&A with SSI lesions reported by Pye et al (2019 VS)
What was the overall STS and the differences in STS for R&A or no R&A
- Pre-op NG reflux
- Pre-op amotile SI on US
- Increased difference in peritoneal vs blood lactate
Overall STS was 78.6% (191/243)
- 68/71 (95.8%) for non R&A
- vs 123/163 (75.5%) for R&A
Main causes of POR in SI sx cases
- Functional* ileus (medical reasons)
- Mechanical* obstruction, incl anastomotic complication, mesenteric kinks etc (surgical reasons)
Can be difficult to distinguish between the 2 broad categories before second sx/PM
Reported complication rates following second laparotomies
59-76%
According to Jacobs et al (2019 VS), what peri-operative variable may help guide the decision to perform repeat laparotomy in horses with POR following small intestinal surgery?
1) Increased peak PO rectal temp; for every °F increase, 4.58 fold more likely to have surgical reason for POR
2) Developing PO colic later in the post-op period (ie not in the first few days PO) was assoc with incr liklihood of surgical reasons - for every 12 hours later, the odds increased by 1.40-fold (140%)
Volume/duration of reflux not assoc w sx reason for POR (vs Dunkel 2015 where higher volumes assoc w functional ileus)
What PSO2 value is indicative of lack of intestinal viability (small or large) with use of surface oximetry?
PSO2 <20mmHg assoc with 7.4X increased liklihood of death
PSO2 values have to be interpreted cautiously. Sensitivity only 53% whereas specificity 100% Consequently, the technique is very useful for detecting horses that will survive, but predicting nonsurvival in horses with low PSO2 values is very inaccurate
Secretin in the small intestine
What stimulates its release, where is it released from and what are its effects?
Stimulated by H+ ions in the duodenum
Released from doudenal S cells
Causes the liver to secrete bicarb & water. Bicarb neutralises stomach acidity & optimises solubility of bile acids and fatty acids
What stimulates release of CCK, where is it released from & what are the main actions?
CCK stimulated by the presence of fat/protein in the duodenum
Released from duodenal I cells
Stimulates the pancreas to release digestive enzymes incl amylase, lipase, trypsinogen
Secretin & gastrin also stimulate pancreatic secretion
Where is tripsinogen activated?
Activated in the intestinal lumen by the brush border enzyme enterokinase
Tripsin is the active form. Tripsin is responsible for activation of all other zymogens/precursors
Outline steps for jejunal resection & anastomosis
- Correct lesion (if poss) & maintain bowel in correct orientation. Isolate ideally w lap sponges or buster
- Double/triple ligate mesenteric vessels supplying affected portion of the bowel - need 50cm healthy margins & resected ends need to be <10cm from the major jejunal artery. (2-0 or 3-0 PDS or polysorb fine)
- Penrose through mesentery around bowel either side of proposed resection sites (oral one can be left off until decompressed if planning to decompress out of SI)
- Transect mesentery distal to ligatures - maintain equal distance from the bowel along line of mesenteric transection
- Gather resected mesentery - secure short end with a haemostat and gather entire length with long end. Don’t tie
- Place Doyens at the proposed resection sites - should be placed 50deg to the mesentery - ie leaving mesenteric side longer.
- Transect aboral SI at described angle & decompress SI - ideally getting rid of contents out of horse (this can be done at the beginning decompressing into the caecum)
- Mesenteric gathering suture can be tied after decompression
- Transect other (oral) end of jejunum and discard resected intestine
- Perform anastomosis - appose mesenteric (1st) and antimesenteric borders with single interrupted Lembert. Then do either interrupted or continuous interrupted 180 Lembert with minimal inversion to complete anastomosis. Ideally don’t leave clamps on throughout all but can keep while getting initial sutures in. Penroses should stop significant contamination. 3-0 or 2-0 PDS
- Close remaining linear mesenteric defect from gathered portion toward bowel
According to Espinosa et al (VS 2017) what pre & intra-op variables were assoc with nonsurvival to GA recovery and non-survival to DC with sx correction of SSI lesions?
Pre-op:
- Diff between peripheral & peritoneal lactate (DIFL) (>3.1mmol/L) assoc w non-survival to DC or GA recovery
- Others incl ↑ PCV & NG reflux >2L (not sig in multivariable/not in abstract)
- Pre-op tachycardia no sig assoc despite findings of other studies
Intra-op
- Tachycardia & sx time >3hr 46min- assoc w nonsurvival to GA recovery
- Hypotension, hypocapnia, low PCV, tachycardia - all assoc w non-survival of GA recovery
- Performing R&A and JC anastomosis specifically assoc w non-survival to discharge & req for relaparotomy
What were the findings of Kilcoyne (JAVMA 2016) et al WRT short term outcomes of horses with EFE and gastrosplenic ligament entrapment?
- Middle age geldings over-represented vs colic population in both groups
- EFE horses generally had more severe CV derangements; higher mean HR & Ptap lactate
- Overall survival rates not sig diff - EFE - 40%, GLE 51%
- Survival rates of those tx sx not sig diff - EFE 85%, GLE 89%
- Survivors across both groups had lower peritoneal fluid TP & lactate pre-op (69% ↓ survival for every 1g/dL incr in Ptap TP)
- PO NG reflux 89% less likely to survive; incidence of POI simialr between groups
What was the incidence of POR in the paper by Jacobs et al (VS 2019)?
What proportion of horses treated medically for POR, and surgically for POR, survived to DC?
Incidence of POR 22.3%
97% STS w medical management
60% STS w surgical management of POR
Main findings of Bauck et at (VS 2017) with early repeat laparotomy for tx of POR/POC after sx correction of JEJUNAL strangulations
- Re-laps all performed through same ventral midline incision.
- ↑ incisional complications - 13/17 (76%) infection. 4/13 infected incisons got hernias (31%)
- 2nd sx at median 57hr post 1st sx & 16 hr post POR development
- All that recovered GA survived to DC
Suggest that POR/POC with JEJUNAL lesions should promt EARLY sx intervention (as functional POI less common w JJ anastomoses) - & is assoc w GOOD outcomes - 9/11 with anastomses had revisions & 4/8 without had anastomosis at 2nd sx
What is the crown length, leg length & closed height of the green cartridge staples for the TA090/GIA/ILA?
What about blue? (these are seldom used in EQ sx as too small)
Leg length - 4.8mm (this is how the staples are named)
Crown length 4mm
Closed height 2mm.
Blue staples are 3.8mm, closed height 1.5mm
