Subarachnoid microcatheter anesthesia in small children

Standard single dose spinal anesthesia is a recognized technique for neonates and small children. The advent of the subarachnoid microcatheter technique potentially expands the use of spinal anesthesia. The authors studied the use of repeated neuroblock via spinal catheters in 10 children under 5 years, undergoing major abdominal surgery of 2 hours or longer.

The children had a mean weight of 8 +/- 1.8 kg and a mean age of 12.5 +/- 5.7 months. General anesthesia was administered as isoflurane 1%-1.5% in a 50% oxygen in air mixture via an endotracheal tube connected to an Ohmeda ventilator. A Kendall Cospan microcatheter pack was used to place a 28-gauge catheter via a 22-gauge needle at the L4-5 or L5-S1 interspace. Isobaric plain bupivacaine 0.5% was injected at 0.2 mL/kg, up to a maximum of 1 mL. This was repeated whenever the pulse or systolic blood pressure rose above 20% of baseline values. Neurologic examinations for motor or sensory deficits were done 24 hours after the block, at discharge, and 1 month later.

The catheters were easily placed and removed without difficulty. Surgical conditions were excellent and, as judged by pulse and blood pressure, analgesia during surgery was optimum. The mean duration of the neuroblock was 59.7 +/- 2.1 minutes. Systolic blood pressure decreased initially by a mean of 8% (6.5 +/- 0.7 mmHg) and after follow-up doses by 2%-6% below baseline values. On recovery, analgesic levels were T1-T6. Three children had the catheters left in situ for postoperative analgesia. All three leaked 2-3 mL of clear glucose-containing fluid alongside the catheter overnight. No neurologic deficits were seen.

The technique was a very effective method of providing adjunct operative anesthesia in infants and small children. Analgesia, muscle relaxation, and cardiovascular stability were present and no complications arose besides the apparent cerebrospinal fluid leak. The resultant risk of infection or possible duracutaneous fistula formation contraindicates the use of subarachnoid catheters of 28 gauge for postoperative analgesic use in young children.