Incidence rate and factors associated with periprocedural hypoxia during bedside intravitreal ranibizumab injection for retinopathy of prematurity: a multicenter retrospective study

Abstract Background Intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy has become an established treatment for type 1 retinopathy of prematurity (ROP). However, evidence regarding intraprocedural hypoxia during bedside intravitreal injection remains limited. This study evaluated the incidence, severity, and predictors of hypoxia during intravitreal ranibizumab injection for treatment-requiring ROP. Methods This retrospective multicenter observational study included premature infants with treatment-requiring ROP who underwent bedside intravitreal ranibizumab injection under topical anesthesia between July 2020 and June 2026 in neonatal intensive care units across the Al Qassim region, Saudi Arabia. Continuous pulse oximetry was used during the procedure and for 30 minutes afterward. Hypoxia was classified as mild (oxygen saturation 85–89%), moderate (80–84%), or severe (< 80%). Demographic, perinatal, maternal, and ophthalmic variables were analyzed. Logistic regression was performed to identify factors associated with hypoxia. Results Seventy-four premature infants out of 1430 were included. The mean gestational age was 27.5 ± 2.2 weeks, the mean birth weight was 986.8 ± 265.8 g, and the mean postmenstrual age at treatment was 36.6 ± 2.2 weeks. Hypoxia occurred in 12 infants (16.2%; 95% CI, 8.7–26.6%), including 10 (13.5%) with mild hypoxia and 2 (2.7%) with moderate hypoxia; no episodes of severe hypoxia were observed. Lower gestational age (OR 0.51, 95% CI 0.35–0.76; P = 0.001), lower birth weight (OR 0.991 per gram increase, 95% CI 0.984–0.997; P = 0.004), and longer duration of oxygen therapy (OR 1.35, 95% CI 1.03–1.77; P = 0.028) were associated with hypoxia in univariate analysis. After adjustment, birth weight remained the principal predictor of increasing hypoxia severity. At follow-up, regression of ROP was achieved in 60 infants (81.1%), while 4 (5.4%) required repeat ranibizumab injection and 10 (13.5%) underwent adjunctive laser photocoagulation. Conclusions Bedside intravitreal ranibizumab injection under topical anesthesia was associated with a low incidence of transient hypoxia, and no severe oxygen desaturation events occurred. Lower birth weight and lower gestational age were associated with an increased risk of hypoxia. These findings support the short-term cardiorespiratory safety of bedside ranibizumab injection in premature infants while emphasizing the importance of continuous physiological monitoring, particularly in extremely low-birth-weight infants.