Intravenous hypertonic saline to reduce intraocular pressure: the effect of splitting the bolus

Purpose To compare intraocular pressure (IOP) and pain after a single versus split bolus of intravenous hypertonic saline (IVHTS). Methods In a prospective, randomized, interventional trial, we enrolled patients with an IOP of 22-34 mmHg. Twenty patients in Group 1 received IVHTS as a single bolus of 1 mmol/kg 23.4% sodium chloride, and 13 patients in Group 2 received two boli of 0.5 mmol/kg separated by 10 min. They graded pain at the infusion site. We measured IOP, heart rate and blood pressure before and 10 and 20 min after IVHTS. Results Eighteen patients (90%) in Group 1 felt pain (median, 6.5; range, 0-10). In Group 2, 11 patients (85%) felt pain after the first bolus (median, 6.0; range, 0-8) and 12 (92%) after the second one (median, 8; range, 0-10). We found no difference in pain grade between the groups after their first bolus (p = 0.33) or between the first bolus of Group 1 and the second bolus of Group 2 (p = 0.47). The median IOP reduction in Group 1 was 6.5 mmHg (range, 2-16) at 10 min and 7.0 mmHg (range, 4-16) at 20 min (p < 0.001 for both). In Group 2, the corresponding reductions after the second bolus were 9.0 mmHg (range, 4-10; p = 0.002) and 8.0 mmHg (range, 6-11; p = 0.002). The IOP reduction at 10 and 20 min was comparable between groups (p = 0.094 and p = 0.41, respectively). Conclusion Splitting the bolus did not reduce pain associated with IVHTS. Single bolus is consequently recommended.

Automated summary

This study compared the effects of single versus split bolus of intravenous hypertonic saline on intraocular pressure and pain, finding that splitting the bolus did not reduce pain associated with IVHTS. Therefore, a single bolus is recommended.