Efficacy of Incentive Spirometer in Increasing Maximum Inspiratory Volume in an Out-Patient Setting

Background Incentive spirometry (IS) is the mainstay of care in postoperative patients that has been heavily studied in the inpatient setting. Studies have shown that the utilization of IS improves lung volumes and reduces the rate of pneumonia in post-surgical patients. However, the literature is ambiguous on its benefit as many studies also demonstrate no significant benefit, especially in comparison to early ambulation. Our study sought to determine whether a consistent IS regimen can improve lung function in an outpatient setting. Methods This prospective cohort study included patients in a physical medicine and rehabilitation clinic setting during the COVID pandemic. Patients with severe respiratory disease, baseline cough, those unable to perform deep breathing, fever greater than 100.4 F due to non-pulmonary on initial evaluation, or inability to fill out the forms and complete the study were excluded. Each participant was given the IS along with hands-on instruction on how to use the device and accurately record measurements. Patients were asked to lie down and inhale and exhale through the tube ten times. They were asked to mark the highest volume during their 10 breaths. Patients were instructed to complete this exercise three times a day for 30 days. Patients were also asked to perform light exercises or walking for 20 minutes per day three times a week and postural drainage. Patients were instructed to call their primary care physician if a 20% or more decrease from their baseline was noted or if they experienced any new coughs, fever, or shortness of breath during the 30 days of exercise. Results A total of 48 patients enrolled in the study with a (median) age of 58.0 years (SD 10.2 years), 21 females and 27 males. Baseline maximal inspiration for study participants was 1885.4 mL prior to exercise, with a subsequent increase in lung capacity observed for all participants enrolled in the study. At the end of the study period, week four, the average maximal inspiratory volume was 2235.4 mL. Paired t-test showed a significant difference between baseline (1885.4) and maximum (2235.4) volumes (t=-4.59, p<0.0001). Analysis of variance (ANOVA) showed no significant difference among Week 1-4 averages (F=1.08, p=0.36). None of the participants reported any symptoms (fever, coughing, shortness of breath) or COVID-19 infection during the 30-days period. None of the participants reported contacting primary care physicians.  Conclusion When prescribed daily breathing exercises with an incentive spirometer, study participants experienced a 16% increase in maximal inspiratory volume over a span of 30 days and did not need to contact their primary care physician during the study period.