PURPOSE: Obesity is associated with both changes in lung volumes and increased incidence of Sleep Disordered Breathing (SDB). We evaluated patients to determine whether there is an association between a decreased ERV and an increased AHI.
METHODS: Records from patients that contained a full set of Pulmonary Function Tests (PFT) and a polysomnogram obtained between 10-1-1998 and 9-30-2005 which were avaiable in the electronic patient chart were reviewed. There were 219 patient charts available with 4 excluded (3 for uninterpretable lung volumes and 1 for poorly recorded sleep data), leaving 215 patients for analysis. SDB was defined as an AHI >15. Low ERV was defined as below the lower limit normal. Obesity was defined as a BMI ≥30.
RESULTS: As expected, a low ERV was associated with an increased BMI and an increased BMI was associated with an increased AHI (Fisher Exact Test, P<0.05 for both). BMI averaged 34.2±7.1 kg/m2, ranging from 18.6-69.2. The table below demonstrates the association between ERV and AHI (Fisher Exact Test, P<0.05). Since all BMIs in the 4 groups fell within ±1S.D. of the mean, a low ERV provides additional information besides obesity about the possibility of SDB in this group.
CONCLUSION: There is an association between ERV and AHI, regardless of BMI.
CLINICAL IMPLICATIONS: With an increasing incidence of obesity and SDB, a low ERV may provide another indication to evaluate a patient for SDB symptoms regardless of BMI.
DISCLOSURE: Kathy Wilson, No Financial Disclosure Information; No Product/Research Disclosure Information