Anaesthesia with and without dexmedetomidine for a child with multiple congenital anomalies posted for bilateral cataract extraction
A 5-month-old, 3.67 kg, male baby presented with bilateral mature congenital cataracts and was posted for sequential bilateral eye lens excision and anterior vitrectomy under general anaesthesia.\nThe baby was delivered as a full-term baby by normal delivery and his low birth weight (1.8 kg), fever, jaundice with hepatosplenomegaly necessitated neonatal intensive care unit (ICU) admission for 15 days. He was investigated for congenital rubella syndrome, but serology was not supportive. Atrial septal defect (ASD) was identified preoperatively by clinical examination and echocardiography. Echocardiography revealed mild pulmonary hypertension with, secundum type of ASD (4 mm) with left to right flow. Baby had right sided cleft lip and palate, bilateral mature cataracts, no signs of cyanosis, and infection or congestive cardiac failure. The baby had normal heart rate (HR) (140/min, regular) and respiratory rate (40/min) maintaining good oxygen saturation (99%) on room air. However, icterus was evident.\nLungs were clear. An ejection systolic murmur was heard, which was most prominent over the pulmonary area of the precordium. On per abdominal examination, hepatosplenomegaly was palpable. The child was irritable, but neurologically normal.\nHis routine pre-operative haematological and biochemical investigations were normal. C reactive proteins were negative. However, high reticulocyte count (4.7%), with unconjugated hyperbilirubinemia (total 18.2 mg%, direct 3.1 mg%, indirect 15.1 mg%) was suggestive of pre-hepatic jaundice.[]\nX-ray chest depicted cardiomegaly with normal airway and lung fields. Electrocardiogram (ECG) revealed right axis deviation and incomplete right bundle branch block.\nThe child was kept nil by mouth for 4 h prior to the surgery. The child was pre-medicated with oral midazolam 1.5 mg 45 min before surgery and intravenous glycopyrrolate 15 μg 10 min before surgery.\nIn the operating room, monitoring included heart rate (HR), mean arterial pressure, pulse oximetry, ECG and end-tidal carbon dioxide monitoring (EtCO2) carried out throughout both operations. While IOP was measured (using Schioetz tonometer) before and after giving pre-medication, before administration of succinylcholine, immediately after intubation, and then every 2 min for 6 min before starting both the surgeries.\nAnaesthesia was induced with thiopentone sodium (20 mg, in two 10 mg doses) and suxamethonium (10 mg) was injected for muscle relaxation after ability to mask-ventilate the patient was confirmed. Intubation was achieved using No. 3 sized plain endotracheal tube. Pressure-controlled ventilation was used manually with 250 ml bag attached to Ayres T piece to maintain mild hypocarbia. Anaesthesia was maintained with oxygen, nitrous oxide (50:50) and sevoflurane (2-4%), and atracurium. Dextrose with 0.33% saline was infused at the rate of 2.5cc/min (total 150 cc) with the help of infusion pump. Patient was haemodynamically stable throughout the intra-operative period. At the end of surgery, neuromuscular blockade was reversed with neostigmine 0.2 mg and glycopyrrolate 30 μg. On recovery of vital reflexes, baby was extubated. Dexamethasone 0.5 mg was given intravenously before shifting the baby to paediatric ICU.\nPost-operative course was uneventful except the emergence agitation, which was partially alleviated by tramadol suppository (12.5 mg) and presence of his mother in paediatric ICU.\nHe was rescheduled for surgery of the other eye after 10 days. Second time Dexmedetomidine 0.5 μg was given intravenously over 10 minutes in addition to other premedicants. Rest of the anaesthetic management was similar and uneventful.\nFor second surgery, there was 50% reduction in the dose of thiopentone sodium and concentration of sevoflurane required to keep adequate depth of anaesthesia was 3%. Maximum drop in HR was 10% of baseline during the first operation while it was 22% during the second operation. Succinylcholine and intubation increased IOP during both the operations. However, during the second operation, after premedication with dexmedetomidine, the IOP rise was not different from the baseline value (before premedication) and was significantly lower than that of the first surgery. After the second surgery, the child was awake, but quiet.