MOTION MANAGEMANT IN LUNG SBRT BY DR KANHU CHARAN PATRO
Acute and chronic mesenteric ischaemia(1)
1. Approach and management of
Acute mesenteric ischaemia
Dr shambhavi sharma
1st year Resident
PAHS
2. • On 3rd January 2017, The Mesentery has been declared as a New
Organ and has been published in The Lancet Medical Journal(The
Lancet Gastroenterology & Hepatology) by J Calvin Coffey, a
researcher at the University Hospital Limerick, Ireland
• Gray’s Anatomy has already been updated with the definition.
3.
4. Acute Mesenteric Ischaemia
• a catastrophic abdominal emergency
• characterized by sudden critical interruption to the intestinal blood flow
• commonly leads to bowel infarction and death
• uncommon but life-threatening disease
• Incidence ~1 in every 1000 hospital admissions
• Mortality remains as high as 60-80%
• Prognosis is poor
• Mark et al Semin Vasc Surg 23:9-20 ,2010
5.
6. Areas prone to ischemia
• the watershed areas between the major vessels that supply the colon
are at risk for ischemia
• Narrow terminal branches of the SMA supply the splenic flexure,
• narrow terminal branches of the IMA supply the rectosigmoid
junction.
7. Splenic flexure –
• Griffiths' point :
• the site of communication of the ascending left
colic artery with the marginal artery of Drummond
• anastomotic bridging between the right and left
terminal branches of the ascending left colic artery
Rectosigmoid junction –
Sudeck's point:
the descending branch of the left colic artery forms
an anastomosis with the superior rectal artery
8.
9.
10. Physiology and mechanism of ischaemia
Normal physiology
• The splanchnic circulation receives between 10 to 35 percent of cardiac
output
• capillary density within the intestinal vasculature is high compared with
other vascular beds
• intestinal oxygen extraction is relatively low
• The intestine is able to compensate for an approximately 75 percent reduction
in mesenteric blood flow for up to 12 hours without substantial injury
11. Intrinsic autoregulation of blood flow :
• direct arteriolar smooth muscle relaxation
• a metabolic response to adenosine and other metabolites of mucosal
ischemia
Extrinsic regulation :
• the sympathetic nervous system
• the renin-angiotensin axis
• release of vasopressin from the pituitary gland
Intestinal blood flow must be reduced by at least 50 percent from
the normal fasting level before oxygen delivery to the intestine
12. Pathophysiology
Ischemia(perfusion pressure < 30mmHg,mean MAP
<45
Mucosal barrier disruption Substantial protein-rich fluid loss
Release of bacteria, toxins, vasoactive substance hypovolemia
SIRS
MODS
Death
13. Clinical presentation
Early symptoms
• Severe Abdominal pain that is
out of proportion to physical findings
in 95% cases
• Prominent symptoms of GI
emptying
( nausea, vomiting , diarrhea )
• Post prandial pain (SMA
thrombosis)
• Waxing and waning pain (SMV
thrombosis)
14. Late symptoms
• Bloody diarrhea
• Abdominal distension
• Features of Peritonitis-
Fever
Shock
Tachycardia
20. Doppler study
• Able to identify severe stenosis or total or partial occlusion and
velocity of blood flowing through the vessels
• Unable to detect emboli beyond the proximal main vessel
• Non-obstructive mesenteric ischaemia
partially occluded Artery
21.
22.
23.
24. Angiography
• Gold Standard
• Non-invasive : CT-Angiography
Magnetic Resonance Angiography
Invasive : Catheter (Conventional Method)
Findings on Angiography: Filling defects
Stenosis or blockage
25.
26. Risk for mortality
• Older age
• Elevated serum aspartate
aminotransferase
• Increased blood urea nitrogen
• Metabolic acidosis
• Significant co-morbidities and poor
performance status
• Intestinal necrosis
• Increased elapsed time to
laparotomy(24hr)
• When the colon involved
Aliosmanoglu I et al. Int Surg. 2013
Gupta PK et al. Surgery. 2011
27. • Symptoms >24hr=Mortality increases dramatically
• when <12h= Gut viability 100%
• 56% when 12~24hr
• 18% when >24hr
• Revascularization performed within 12 h from the onset of symptoms.
• Resection of non-viable bowel should be performed without delay
Aliosmanoglu I et al. Int Surg. 2013
28. INITIAL MANAGEMENT
• Gastrointestinal decompression
• fluid resuscitation
• hemodynamic monitoring and support
• correction of electrolyte abnormalities
Antibiotics — Broad-spectrum antibiotic therapy
Pain control — parenteral opioids
29. Anticoagulation
• systemic anticoagulation needed to prevent thrombus formation and
propagation
C/I: actively bleeding, as in ischemic colitis related to nonocclusive ischemia
• For those who require abdominal exploration, anticoagulation is typically
continued after surgery to prevent new thrombus formation
30. Definitive surgical exploration
• Approach : midline laparotomy
1.Assessment of bowel viability
2. Determination of underlying cause
3. Mesenteric revascularization
4. Resection of necrotic bowel
5. Second look laparotomy
31. Assessment of bowel viability
1. Clinical Judgment
• pink serosa
• visible peristalsis
• positive pulsations
• bleeding from cut edges
• 2. Doppler USG - hand-held Doppler(Detects anti-mesenteric
blood flow)
• 3. Fluorescein -Injection of IV Sodium fluorescein(1gm) and
inspection under Wood’s lamp (Viable bowel has smooth,
uniform fluorescence)
36. Second look surgery
• Planned second look techniques are required after restoration of SMA flow,
with or without resection of ischemic bowel following resuscitation in intensive
care unit
• Given frequent uncertainty with regard to bowel viability, the stapled off bowel
ends should be left in discontinuity and re-inspected after a period of
continued ICU resuscitation to restore physiological balance.
• Often, bowel which is borderline ischemic at the initial exploration will improve
after restoration of blood supply and physiologic stabilization
37. • re-exploration should be accomplished within 48 h
• decisions regarding anastomosis, stoma, or additional resection can
be made with plans for sequential abdominal closure.
39. • Acute mesenteric ischemia: guidelines of the World Society of
Emergency Surgery 2017
• Sabiston text book of surgery
• Uptodate
Editor's Notes
Griffiths' point is defined as the site of communication of the ascending left colic artery with the marginal artery of Drummond, and anastomotic bridging between the right and left terminal branches of the ascending left colic artery at the splenic flexure of the colon It is a critical area of weakness of the blood supply of the splenic flexure that is prone to ischemia.