Imperforate Anus and administration of Anesthesia

1. IMPERFORATE ANUS
Speaker: Dr Bhagirath.S.N
Moderator: Dr Sarika

2. Imperforate Anus
• Incidence: 1 in 5000 births
male preponderance
• noticed initially as failure to pass meconium
• Persistence of the cloacal membrane results
in an imperforate anus
• can be associated with congenital anomalies such as
Vertebral anomalies-hemi-vertebra, hypoplastic vertebra
Anal defects
Cardiac defects-atrial septal defect, ventricular septal defect, tetralogy of fallot
Tracheo-Esophageal, esophageal atresia
Renal defects
Limb defects-hypoplastic thumb, polydactyl, syndactyl, radial aplasia.

3. Imperforate Anus
High lesions
• rectum ends above the levator ani
muscle
• long term fecal incontinence
• communication with urethra in males
and vagina in females
• surgery-colostomy preceding repair
Low lesions
• rectum ends below the levator ani
muscle
•communication with skin in the
perineum, median raphe of scrotum, or
into the vaginal vestibule• perineal anoplasty with closure of fistula, creation of anal opening, repositioning
the rectal pouch into the anal opening.

4. Imperforate Anus-preoperative assessment
•Assess for other anomalies with
 Ultrasound of renal system
 Chest X-ray
 ECG
 Echocardiogram
 X rays of lumbar and sacral spine
• Presentations
 abdominal distension
 impairment of ventilation, apnea
 Bowel ischemia

5. Imperforate Anus-Anesthetic technique
1. Obtain I.V.access
2. Atropine 20 mcg/kg IV if desired.
3. Induction can be IV or inhalational.
4. Endotracheal intubation and IPPV.
5. Maintenance is with volatile anesthetic in oxygen and air.
6. Patients are positioned supine for colostomy. For anoplasty or EUA of the
perineum the lithotomy position (or as near to it as possible in a neonate) is
used with the hips and knees flexed and then taped in this position. The child is
usually positioned at the far end of the operating table.
7. Options for analgesia include:
1. Anoplasty: a caudal epidural block as a single injection to block sacral
dermatomes— 0.3-0.5 mL/kg 0.25% levobupivacaine or similar.

6. Imperforate Anus-Anesthetic technique
2. Colostomy: requires blockade of thoracic dermatomes. A single caudal
epidural injection—1.25 mL/kg 0.125% levobupivacaine or similar—or
insertion of a caudal epidural catheter. The catheter can be used for a
postoperative infusion.
3. The sacrum is occasionally anatomically abnormal in anorectal anomalies
and a caudal technique may not be possible.
4. An intervertebral epidural to block thoracic dermatomes.
5. IV opioid: morphine sulphate 25-50 mcg/kg IV; fentanyl citrate 1-2 mcg/kg
IV.
6. All of these techniques can be supplemented by IV paracetamol 15 mg/kg.
8. Occasionally during a colostomy some volume replacement is required.

7. Imperforate Anus-Postoperative care
1. Patients are usually extubated.
2. Maintenance fluids are required until feeding is established.
3. Analgesia should be adequate—paracetamol 15 mg/kg oral 6-hourly (maximum
60 mg/kg/day) and a weak opioid such as codeine phosphate 0.5 mg/kg oral 4-
hourly.
4. After formation of a colostomy the options are an IV infusion of morphine
sulphate or an epidural infusion of LA usually for 24 hours.