Does salivary pH affect postoperative sore throat in the head‐down position of general anesthesia?

• Published in: Journal of oral rehabilitation 2024-07, Vol.51 (7), p.1202-1206
• Main Authors: Koike, Masayoshi, Abukawa, Yukako, Kaji, Keiko, Satou, Kazuki, Takahashi, Kazunari, Nakamura, Makoto, Hasunuma, Jun, Imura, Hideto, Natsume, Nagato, Abukawa, Harutsugi
• Format: Article
• Language: English
• Subjects: Anesthesia; head‐down surgery; laparoscopic surgery; Laparoscopy; Nerves; Oral cavity; Patients; pH effects; Pharyngitis; Pharynx; postoperative sore throat; Saliva; salivary pH; Surgery
• ISSN: 0305-182X; 1365-2842
• DOI: 10.1111/joor.13694

Background Tracheal intubation sometimes causes postoperative sore throat (POST) due to laryngeal damage. However, clinical observations suggest that the environment of the oral cavity may also affect POST. Objective The purpose of this study was to investigate whether salivary pH in the oral cavity affects POST. Methods After obtaining ethical approval, informed consent was obtained from all patients. Patients who underwent surgery in the supine position were enrolled as the control group. Patients who underwent laparoscopic surgery in the head‐down position were enrolled as the intervention group. Immediately before both groups of patients were anaesthetised, expelled saliva was collected, and salivary pH was measured. Immediately postoperatively, the same measurement was carried out before the patient regained consciousness. The primary outcome was the change in salivary pH. The secondary outcome was POST. In our study, POST was defined as pharyngeal and swallowing pain in the glossopharyngeal and superior laryngeal nerves. The normal distribution of pH was tested using the Shapiro–Wilk test followed by analysis using repeated‐measurements and one‐way analysis of variance. Statistical significance was set at p