Preoperative Management,Intraoperative Management and Postoperative management of intestinal obstruction

1. ANESTHESIA FOR
INTESTINAL OBSTRUCTION

2. Preoperative Management
1. Fluid and Electrolyte Imbalance
2. Bowel and Abdominal Distention
3. Respiratory Problem
4. CVS Problem
5. Vomiting, Regurgitation and Aspiration.
6. Investigation
7. Premedication

3. 1. Fluid and Electrolyte Imbalance
 Dehydration:
 Normally 7-9L of fluids are secreted into the upper
intestinal tract daily.
 In small intestinal obstruction, fluid loss occurs due to:
 Accumulation of fluids
 Increased secretion
 Decreased reabsorption
 This causes loss of isotonic salt water resulting in
isotonic contraction of ECF volume.
 SO; dehydration and increased hematocrit occur.

4. 1. Fluid and Electrolyte Imbalance
6000ml of fluid accumulation in bowel.
At late stages with hypotension and tachycardia
3000ml of fluid accumulation in bowel.
At Well established cases with vomiting
1500ml of fluid accumulation in bowel.
At Early stage

5. 1. Fluid and Electrolyte Imbalance
 The degree of dehydration is evaluated by:
1. Duration of illness
2. Presence of vomiting
3. Skin elasticity
4. Sunken eye
5. Oliguria....ect.
 The dgree of ECF loss can be monitored by serial
hematocrit determinations
 Rise in Hct is proportional to the amount of fluid loss.
 If Hct increases to 55% this indicates that about 40% of
plasma and ECF volume have been lost.
 Treatment
 2-6 liters of IV fluid are needed according to the degree of
dehydration by RL or NS

6. I. Fluid and Electrolyte Imbalance
 Electrolyte Disturbances:
1. Hyponatremia and Hypochloremia.
 Because fluid accumulation and vomiting.
2. Hypokalemia.
 Mainly due to renal mechanisms.
 Secondary to metabolic alkalosis and hyperaldosteronism.
 Acid Base Imbalance:
 Metabolic Acidosis are more common due to:
 Dehydration and loss of alkaline intestinal secretion
 Starvation ketosis.

7. II. Bowel and Abdominal Distention
 Occurs due to accumulation of fluids and gases.
 Resulting in:
a. Blockade of the venous outflow.
b. Blockade of the blood supply to the obstructed segment.
c. Hindering of diaphragmatic movement.
d. Decreasing venous return.
e. Progressive distention may cause rupture of colon.
f. Progressive distention may cause tense abdominal wall.

8. II. Bowel and Abdominal Distention
 We need:
1. Naso-gastric tube for abdominal decompression in
preoperative Mx..
2. Deeper anestheisa and muscle relaxants to provide
adequate operative conditions.
3. Gradual escape of fluid and Monitor BP frequently during
incision.( sudden escape of fluids into the peritoneal
cavity may cause severe hypotension ).

9. Role of nasogastric aspiration
1. Reduce bowel distension
2. Improve pulmonary ventilation
3. Reduce risk of subsequent aspiration during induction of
anesthesia and post extubation

10. III.Respiratory Problems
 Due to:
1. Abdominal distention which hinders the diaphragm
resulting in inadequate ventilation.
 This decreases ( Vt, FRC, ) and causes a decrease in
PaO2 and an increase in PaCO2.
2. Weakness of intercostal muscles due to hypokalemia.

11. IV.CVS Problem
 Hypotenion and Tachycardia up to shock.
 Due to:
1. Hypovolemia
2. Decreased VR.
3. Septic shock
4. Hyponatremia
 Arrhythmias ( ventricular ).
 Due to:
1. Hypokalemia

12. V. Vomiting, Regurgitation and Aspiration.
 Reversal of peristalsis and mechanical obstruction
pushes the intestinal juice in addition to the gastric juice
to produce a full stomach with an increased inta-
abdominal pressure.

13. VI.Investigation
1. X-ray abdominal in supine and erect position:
 To ensure diagnosis of intestinal obstruction.
2. Ix. To detect complications:
 Hct.
 WBCs
 Elecrtolytes, Acid base disturbances.
 Atrerial blood gases PaO2 and PaCO2.

14. VII.Premedication
 Avoid all oral premedication.
 Avoid drugs that may inhibit respiration e.g. ( opioids,
sedative, ....
 Avoid anticholinergics e.g. If fever or tachycardia occure.
 Avoid antiacids or H2 blockers although there is a risk of
aspiration as;
 The may stimulate vomiting.
 They are of low value if a large volume of fluids are already
sequestrated in the bowel e.g. High intestinal obstruction.

15. Intraoperative Management
1. Choice of anesthesia.
2. Monitoring.
3. Induction and Intubation.
4. Maintenance.
5. Extubation.

16. Intraoperative management
 Choice of anesthesia
 Regional anesthesia :
 Its avoided if significant fluid depletion is suspected.
 General anesthesia :
 Monitoring:
 Standard + UOP, CVP and PCWP.

17. Intraoperative management
 Induction and Intubation:
 There is a major risk of aspiration causing very high
mortality rates.
1. Awake Intubation:
 In cooperative patient.
 N.B.; Avoid anesthesia of the larynx to avoid loss of
protective reflexes of the larynx against vomiting or
regurgitation.
 Then do laryngoscopy and intubation followed by induction

18. Intraoperative management
2. Rapid sequence crash induction:
 Its done in supine or lateral position with head down tilt
(10 dgree) to avoid aspiration if vomiting occurs.
 Preoxygenation: 8-10L OF 100% O2 for 2-5 min.
 Precurarization (defasciculation) does of NDMR to avoid
suxamethonium fasciculation.
 Naso-gastric tube should be removed before intubation to:
 Allow effective cricoid pressure.
 Avoid lower esophageal sphincter dysfunction.
 Avoid hindering of laryngoscopy and intubation.

19. Intraoperative management
 Iv agents:
1. Thiopentone is a good choice if there is NO hypotension.
2. Ketamin or Etomidate are good choice if there is
hypotenion.

20. Intraoperative management
 Maintenance :
 O2 +Potent inhalational agent+NDMR+IPPV
 Careful titration of doses of inhalation agents is needed to
avoid severe hypotension.
 N2O should be avoided in bowel obstruction because it
increases gas distention which increases intra-luminal gas
volume and pressure.
This results in:
1. More increased abdominal distention
2. Increased bowel ischemia and necrosis.
3. Difficulties with abdominal closure at the end of surgery.

21. Intraoperative management
 Extubation:
 Awake extubation in left lateral position.
 After returning of upper airway reflexes
 After good suctioning.

22. Postoperative management
 Continue the preoperative managment
 Fluid and electrolyte correction.
 Respiratory and CVS monitoring.
 Pstoperative ileus
 Due to hyponatremia and hypokalemia.
 Pstoperative abdominal decompression
 Continued for 5-6 days

23. Postoperative management
 Pstoperative respiratory problems
 Abdominal distention is present
 Abdominal pain is present
 Residual effects of inhaled and IV anesthetic.
 Reduction 15-20 % of FRC more than a week after
any upper abdominal surgery.