OBJECTIVE: To evaluate fluid retention after shoulder arthroscopy using infusion of saline in suspension in order to identify those patients at risk for excessive fluid gain during surgery. METHODS: After only one exclusion a group of 131 patients submitted to shoulder arthroscopy were studied and had their Bodily Mass Index (BMI) assessed for the purpose of obesity classification. The patients were positioned laying on their side with the upper limb on a traction support. Joint distension was performed using saline in suspension with a four-way line and four 2000 ml saline flasks placed at the same height, and infusion pressure varied between 31 and 97 mmHg. Patients were weighted as soon as they were able to reach an orthostatic position by the bedside in the recovery room. Variables studied were pre- and post-operative bodily weight, BMI, amount of saline used in the irrigation system, amount of saline used in intravenous infusion, and length of surgery. RESULTS: The average fluid gain in this series of patients was 1901 (± 968) grams. A moderate correlation was found between saline from the irrigation system and fluid gain (r = 0.372; r² = 0.138; P < 0.001), and between intravenous intake and fluid gain (r = 0,253; r² = 0.064; P = 0.004). When saline intakes were considered as a whole, there is a significant correlation, but with a moderate effect (r = 0.381; r² = 0.0146; P < 0.001). A higher magnitude correlation was found between surgery length and fluid gain of the patients (r = 0.586; r² = 0.264; P < 0.001). When patients with BMI below 30 (normal and overweight) were grouped together and compared to patients with BMI above 30 (obesity grade 1, 2, and morbid), higher fluid retention was found among obese patients (2111 g ± 1144 g) (mean 1900 g) than among non-obese patients (1851 g ± 921 g) (mean 1754 g) (P = 0.292). CONCLUSIONS: The fluid retention found amounted to 1901 (± 968) grams. Only 14.6% of the weight gain found is a result of fluid intake during surgery. Patients submitted to lengthy arthroscopic procedures retain more fluid. Patients with Grade 1, 2, and morbid obesity seem to have a more expressive tendency to gain more weight during surgery.
Shoulder joint; Arthroscopy; Obesity; Body mass index; Irrigation; Prospective studies
