RESUMO
PURPOSE: To investigate the effects in cataract surgery using local anesthesia along with a 30% low-concentration nitrous oxide (N2O) anesthesia compared with local anesthesia only. SETTING: Saneikai Tsukazaki Hospital. DESIGN: Retrospective, consecutive study. METHODS: Patients who underwent bilateral cataract surgery were enrolled. 37 patients using room air inhalation (Air group) and 45 patients using 30% low-concentration N2O anesthesia (70% oxygen, total 6 L/min) at surgery start (N2O group) were retrospectively reviewed. Systolic blood pressure (BPs), diastolic blood pressure (BPd), and heart rate (HR) at surgery start and end, and mean intraoperative oxygen saturation (% SpO2) were examined. Immediately following surgery, a questionnaire using the Visual Analog Scale score was done to determine intraoperative pain, anxiety, memory, and nausea. RESULTS: No systemic symptoms in all patients and ocular complications requiring treatment were observed. For the N2O and air groups, changes in BPs were -5.38 ± 11.07(P = .01) and 1.27 ± 13.61 mm Hg, and HR were -2.24 ± 6.76 and 0.89 ± 5.18 bpm (P = .001), respectively; intraoperative SpO2 was 99.05% ± 0.74% and 97.44% ± 1.31% (P < .001), intraoperative anxiety was 21.76 ± 23.2 and 37.17 ± 32.79 (P = .002), and intraoperative memory was 55.24 ± 36.8 and 68.91 ± 33.81 (P = .01), respectively. No patients experienced intraoperative nausea. There was no statistically difference in BPd (P = .47) and intraoperative pain (P = .62). CONCLUSIONS: Low-concentration N2O anesthesia may not cause respiratory depression, abnormal vital signs, or nausea in cataract surgery. It can suppress intraoperative anxiety and memory and decrease and stabilize vital signs.
