Impact of pregnancy on measures of ventilation in an individual with t10 paraplegia

Abstract

Purpose: Ventilation mechanics are impaired in individuals with spinal cord injury (SCI). Measures of pulmonary function are influenced by level of injury (Cervical vs. Thoracic) and body position (Supine vs. Sitting) (Baydur, 2001). The purpose of this case report was to examine ventilation in sitting and supine over the duration of pregnancy in an individual with T10 paraplegia. Relevance: Knowledge about effects of pregnancy on ventilation in women with SCI may improve PT management and education. Participants: A 36 year old pregnant female having T10 complete SCI for 17 years was identified in a support group meeting. Methods: After explaining the purpose of the study and receiving informed consent the subject's vital signs were measured and health status reviewed. Criteria for exclusion were onset of respiratory illness, new pain, blood pressure (BP) <90 or >200 systolic or diastolic <100mm Hg, heart rate (HR) <50 or >100 b/minute, respiratory rate >20 breaths/minute, or if deep breathing and brief breath holding was against physician advice. Forced vital capacity (FVC), maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP) and chest wall excursion (CWE) at three sites (axillary, xiphoid and lower chest) were measured in supine and sitting. Activity pattern was assessed with the Physical Activity Scale for Individuals with Physical Disability (PASIPD). Measures were taken every 3 weeks for 6 visits from the 20th through the 35th week of pregnancy. Analysis: Dependent variables were compared across time and position. Percent predicted was calculated for FVC (Hawkinson, 2003) and MIP/MEP (Black and Hyatt, 1969). CWE was compared to norms (Harris, 1997). Measures across time were compared to published values for low paraplegia. Results: The subject was 5'5'', 132 lbs at week 20 and gained 10 lbs. Across time, FVC ranged from 2000 to 2300 ml (61-70% pred. FVC) in sitting and from 1500 to 1800 ml (45-54% pred. FVC) in supine. In sitting, % predicted FVC was low compared to published results for SCI at T10 (60-95% pred.). Higher FVC in sitting vs. supine agrees with reports on individuals with low paraplegia. Increase in FVC (2300 ml) at week 35 corresponds to increases published in uninjured females. MIP ranged from -57 to -102mm Hg (66-120% pred. MIP) in sitting and ranged from -65 to -93mm Hg (76-108% pred. MIP) in supine. MIP in sitting trended down as pregnancy progressed but remained stable in supine. MEP ranged from 71 to 108mm Hg (47-71% pred. MEP) in sitting and ranged from 85 to 95mm Hg (56-63% pred. MEP) in supine and was low compared to published results for low paraplegia. MEP was lower in supine than sitting and trended down, decreasing by 10-15mm Hg. CWE trended down losing 1-2 cm at each site except axillary in sitting. PASIPD scores trended down and dropped from 40 to 10, due to reduced housework, toileting and mobility outside the home. Conclusions: Reduced physical activity, MEP and CWE occurred during pregnancy in this person with T10 paraplegia. Implications: Physical therapy may be indicated to restore activity and expiratory function.