CPAP therapy prevents increase in blood pressure after upper airway surgery for obstructive sleep apnoea
The aim of this study was to investigate the efficacy of continuous positive airway pressure (CPAP) therapy following uvulopalatopharyngoplasty (UPPP) to prevent blood pressure (BP) elevation during sleep. Sixteen normotensive patients with OSA were subjected to UPPP with or without septoplasty. These patients were instrumented for 24 h of ambulatory BP recording, polysomnography, nocturnal urinary catecholamine and pain evaluation using a visual analogue scale in the day prior to surgery (D−1), following the surgery (D+1) and 30 days later (D+30). For the D+1, the patients were divided into two groups: the without CPAP therapy group and the with CPAP therapy group. The apnoea–hypopnoea index (AHI) significantly increased in the patients without CPAP therapy compared with the D−1 (74 ± 23 vs. 35 ± 6 times/h, p < 0.05), and in the CPAP group, there was a significant reduction in the average AHI value to 14 ± 6 times/h, p < 0.01. During D+1, we observed an increase in the nocturnal systolic BP (10 %), diastolic BP (12 %) and heart rate (14 %) in the group without CPAP. These metrics were re-established in the CPAP group to values that were similar to those that were observed on the D−1. The absence of nocturnal dipping in the group without CPAP was followed by a significant increase in nocturnal norepinephrine (42 ± 12 μg/l/12 h) and epinephrine (8 ± 2 μg/l/12 h) levels compared with the D−1 (norepinephrine 17 ± 3; epinephrine 2 ± 0.3 μg/l/12 h, p < 0.001). In the patients who used the CPAP treatment, the nocturnal catecholamine levels were similar to D−1. The effectiveness of intravenous analgesic therapy was verified by a significant decrease in the pain scores in patients both with and without CPAP therapy. These data confirm an increase in the AHI on the night following UPPP with or without septoplasty. This increase promotes an absence of nocturnal dipping and a significant increase in urinary catecholamine levels. CPAP therapy was effective to prevent the transitory increase in BP.