The Effect of Preoperative Oral Care Procedures on Postoperative Thirst Discomfort

Aim To determine the effect of an oral care procedure using cold distilled water, initiated in the preoperative period, on the level of discomfort associated with thirst in patients undergoing lung resection.

Methods Settings and Design: This randomized controlled, experimental study was conducted between December 12, 2024, and December 24, 2025 with the participation of a sample of 78 patients who undergoing lung surgery in the Thoracic Surgery Department of a University hospital.

1. Inclusion Criteria for the Study Patients who met the following criteria were included in the study:

• Voluntarily agreed to participate in the study,
• Were over 18 years of age,
• Were able to communicate in Turkish,
• Had an ASA classification of I or II,
• Had restricted oral fluid and food intake during the preoperative period,
• Were scheduled to undergo surgery under general anesthesia,
• Had no open wounds on the mouth or lips,
• Were able to verbally express their thirst status.

1. Exclusion Criteria for the Study

Patients with the following characteristics were not included in the study:

• Did not consent to receiving oral care,
• Experienced fluid-electrolyte balance problems in the preoperative, intraoperative, or postoperative period,
• Were admitted to intensive care after surgery,
• Had an ASA classification of III or IV,
• Vomited more than once in the early postoperative period,
• Had difficulty during intubation during surgery,
• Used medication affecting the oral mucosa or the sensation of thirst,
• Had a diagnosis of diabetes and/or advanced chronic kidney failure,
• Had received chemoradiotherapy within the last 6 months,
• Had tooth sensitivity. Data Collection Tools: The Personal Information Form and the Perioperative Thirst Discomfort Scale were used to collect the data. The Personal Information Form consists of a total of 25 questions: 9 questions addressing the patient's age, gender, educational status, presence of chronic disease, history of previous surgical intervention, smoking status, medications used regularly, and daily water intake; 9 questions addressing the characteristics of the surgery the patient would undergo (diagnosis, type), the duration of preoperative fasting and fluid restriction, medications used during surgery, the method of intubation, fluid balance, and postoperative oxygen use; and 7 questions covering the patient's postoperative monitoring of pain, nausea-vomiting, and vital signs. The Perioperative Thirst Discomfort Scale, developed by Martins et al. in 2017, consists of a total of 6 items and is a 3-point Likert-type scale.

Data Collection: An online randomization program (GraphPad.com) was used to assign the patients included in the study to control and experimental groups, thereby ensuring an equal number of patients (39:39) in both groups.

4 patients were excluded from the experimental group for various reasons (1 death, 1 use of a carbonated mouthwash, 2 withdrawals due to discomfort), the study was completed with a total of n=74 patients (experimental group n=35, control group n=39).

Patients were informed about the study by the researcher, and written and verbal informed consent was then obtained from them. In the experimental group, oral care intervention using cold distilled water was commenced by the researcher/nurse every 4 hours from hospital admission onward. In the oral care procedure, distilled water at +4°C and a soft-bristled toothbrush were used to clean the entire oral cavity, including the teeth, gums, tongue, palate, and cheeks. For patients wearing dentures, the dentures were removed during oral care and, after the teeth were cleaned, reinserted if necessary. In order not to disrupt the patient's sleep the night before surgery, oral care was given before the patient went to sleep, and the next oral care session was applied when the patient woke up on the morning of the surgery. Oral care was then continued at 4-hour intervals until the patient was taken into surgery. Since the timing of patients being taken into surgery varied, the number of times oral care was applied to each patient before surgery was recorded. In the postoperative period, oral care applications were also continued at 4-hour intervals. Patients in the control group received standard pre and postoperative care as part of routine clinical practice. No interventions were made regarding the routine clinical care of these patients. The routine care administered in the clinic includes having patients gargle with bicarbonate after meals following their preoperative admission. Patients' thirst-related discomfort was evaluated using the Perioperative Thirst Discomfort Scale preoperatively and at the 1st, 4th, and 8th hours postoperatively.

In the clinic's routine preoperative practice, patients' oral fluid and food intake is stopped the night before surgery, and no fluid replacement is administered overnight. For patients other than the first surgery of the day, IV fluid therapy with 5% dextrose or lactated Ringer's solution is administered according to the physician's order until the patient is taken into surgery. Oral fluid intake for patients returning from surgery is initiated at the 8th postoperative hour.

Statistical Analysis: The data obtained from the study were analyzed using the SPSS (Statistical Package for the Social Sciences) 26.0 software program. As descriptive statistical methods, mean, standard deviation, median, minimum and maximum values were used for numerical variables, while number and percentage distributions were used for categorical variables. The conformity of the variables to normal distribution was assessed using skewness-kurtosis coefficients and the Shapiro-Wilk test. The Chi-square test was used to evaluate the relationship between categorical variables. In cases where the assumptions of the Chi-square test were not met, Fisher's Exact Test was used. For comparing numerical variables, the Independent Samples t-test was used when the data showed a normal distribution, while the Mann-Whitney U test was used when the data did not show a normal distribution. Repeated measurements at more than two time points were compared using the Friedman Two-way ANOVA. To determine which measurement points the difference detected by the Friedman test originated from, the Wilcoxon Signed-Rank Test was applied as a post-hoc analysis. Spearman's correlation analysis (Spearman's rho) was used to determine the direction and strength of the relationship between numerical variables. Results were evaluated at a 95% confidence interval and a significance level of p<0.05. However, for pairwise comparisons between time points (T1-T2, T1-T3, T1-T4, T2-T3, T2-T4, and T3-T4), Bonferroni correction was applied to control for the probability of Type I error that could arise from multiple comparisons, and the significance level was recalculated and accepted as p<0.0083 (0.05/6).