Laser treatment in infants with retinopathy of prematurity using sub-Tenon's lidocaine anaesthesia and sedation with chloral hydrate

Abstract

Premature infants undergoing laser treatment for retinopathy of prematurity are generally more systemically unstable than the average neonate and are more susceptible to episodes of apnoea and bradycardia [1]. General anaesthesia is associated with an increased risk of complications including ventilatory trauma and complicated extubation. A UK study [2] showed that most units carry out laser treatment for retinopathy of prematurity under general anaesthesia in the operating theatre. We describe an alternative technique using local anaesthetic with sedation, which may be useful in selected cases, and attempt to evaluate pain control during the procedure. Over a year, three out of 12 consecutive infants undergoing laser for retinopathy of prematurity were prospectively identified as suitable based on their stability with handling and requirement for oxygen supplementation. Half an hour before treatment babies were placed on continuous positive airways pressure (CPAP) ventilation and sub-Tenon's block performed with 1–2 ml lidocaine 0.5%. Chloral hydrate (100 mg.kg−1) and paracetamol were given rectally. Laser treatment was performed in an equipped side-room on the neonatal intensive care unit (NICU) with oxygen saturation, ECG monitoring and neonatal nursing support. The Neonatal Pain, Agitation and Sedation Scale (N-PASS; http://www.n-pass.com) was completed for each baby to assess whether adequate pain relief was achieved during the procedure. The goal of pain management is to keep this score ≤3. Intervention is indicated for a score >3. The mean (range) gestational age was 26 (24–29 weeks) and birth weight 657 (542–880) g. The laser procedure lasted 25–30 min per eye. No infant required conversion to general anaesthesia. One baby did not require CPAP after laser treatment and two required CPAP for <8 h each. The mean (range) pain score was 2.8 (0–7) and the mean sedation score was −3 (−4 to 0). Higher pain scores were noted at the beginning of the procedure for each baby and these settled in all cases, after a few minutes. Our study suggests that the use of local anaesthesia with sedation is a safe and effective anaesthetic allowing laser treatment for retinopathy of prematurity in selected babies. It prevents treatment delay while waiting for main theatre and the complications associated with transportation are eliminated. It allows application of the laser quickly and accurately. Pain assessment showed that babies suffer minimal distress. An equipped side room on NICU with neonatal nursing support and a neonatologist are essential. Our study has limitations: the numbers are small; follow-up data are limited; and the N-PASS system relies on a degree of subjective assessment.