Obtaining parotid saliva specimens after major surgery

The purpose of this study was to develop and test a standard method of collecting saliva from postoperative patients. Saliva was collected from patients following major abdominal surgery from both parotid glands in intraoral cups and measured in milliliters. Trained research nurses stimulated saliva production with lemon juice and collected saliva at 4 time points on postoperative day 2. Collection time was measured with a stopwatch, and flow rate was calculated by dividing the amount in milliliters by collection time in minutes. Attrition was 9% due to ineligibility after enrollment and 1 withdrawal. In participating patients (n = 68), there were 272 tests planned and 28% were missing. The reasons were postoperative health problems, hospital discharge, and not wanting to be bothered. When saliva collection attempts were made, three-fourths were successful, but the remainder resulted in "dry mouth." Milliliters, minutes, and flow rate were calculated with and without those with dry mouth. Mean flow rates were 0.23 to 0.33 ml/min excluding those with dry mouth and 0.17 to 0.24 ml/min including those with dry mouth. Saliva variables were correlated with antihypertension medications, opioids, opioid side effects, and length of surgery, but statistically significant correlations were not found consistently at all 4 time points. The findings suggest that nurse-researchers studying biological markers can successfully collect saliva from postoperative patients if they recognize the difficulties and make efforts to minimize and control for them.