Effect of graded water immersion on vital capacity and plasma volume in patients with cervical spinal cord injury.

STUDY DESIGN: A case-control study was conducted. OBJECTIVE: The aim of the study was to test the hypothesis that the increase in hydrostatic pressure on the abdominal wall may be the major determinant of vital capacity (VC) improvement in tetraplegic subjects during water immersion, despite the blood volume shifts from the legs and abdomen to the thorax. SETTING: The study was carried out in the Rehabilitation Center, Brasília/DF, Brazil. METHODS: In total, 11 men with tetraplegia (complete motor lesion, C4-7, 30.4 years old) and 12 healthy controls were studied. Hematocrit level and spirometry values were obtained on dry land and at each level of immersion (the pelvis, xiphoid and neck). RESULTS: Baseline spirometry value of tetraplegic subjects showed reduced VC (53.3+/-17.4% of predicted), whereas all control subjects had >80% of predicted values. Neither group showed significant changes in VC at the pelvic and xiphoid levels of immersion. In tetraplegic subjects, VC increased by 27.2% at the neck level (+/-25.8, P<0.008), whereas in healthy subjects it decreased by 6.3% (+/-5.0, P<0.008). Both groups showed significantly increased inspiratory capacity only when immersed to the neck. Hematocrit level of tetraplegic subjects fell significantly with immersion to the xiphoid and neck levels (P<0.017), which occurred in controls only at the xiphoid level (P<0.017). CONCLUSIONS: Hydrostatic compression may be the main contributor to improving VC in tetraplegic subjects immersed in water. This improvement occurs despite increased plasma volume during immersion.

Maximal static mouth respiratory pressure in spinal cord injured patients: correlation with motor level.

STUDY DESIGN: Transversal. OBJECTIVES: The few studies concerning maximal static mouth respiratory pressures in patients with spinal cord lesions suggest a marked reduction. We studied the correlation of these parameters with the motor level of injury. SETTING: Rehabilitation Center, Brasília/DF, Brazil. METHODS: One hundred and thirty-one patients with traumatic spinal cord injury (C4-L3) were recruited. The participants were assessed by standard spirometry and maximal static mouth respiratory pressure. RESULTS: Forced vital capacity was most reduced in tetraplegics (subgroup C4-C5, 49%+/-25 predicted) and increase successively for each descending subgroup (C6-C8, 61%+/-22 predicted; T1-T6, 70%+/-15 predicted), becoming normal in low paraplegia (T7-L3, 84%+/-15 predicted). There is no evidence of an obstructive disturbance throughout all groups. The lowest average percent predicted of maximal static inspiratory pressure (MIP) was in the subgroup C4-C5 (50%+/-23). The average percent predicted of maximal static expiratory pressure (MEP) improved from 19%+/-14 in the C4-C5 subgroup to 51%+/-19 for T7-L3 subgroup. The average percent predicted of all participants for MIP was 74%+/-30 and for MEP was 37%+/-21. In patients with complete motor lesion, the correlation with the level of injury was stronger for MEP (r=0.81, P<0.0001; r (2)=0.65) than for MIP (r=0.62, P=0.004; r (2)=0.38). No correlation was found among incomplete motor lesion patients. CONCLUSIONS: The linear regression equations for the relationship of percent predicted MIP or MEP to level of injury are applicable only to complete motor lesions and may be useful to establish normative association between them.

Cholinergic bronchomotor tone and airway caliber in tetraplegic patients.

STUDY DESIGN: Case-control study. OBJECTIVES: To evaluate the resting airway caliber in subjects with tetraplegia; to define the participation of cholinergic innervation in this condition; and to determine if baclofen modifies this pattern. SETTING: A rehabilitation hospital, Brasília, Brazil. METHODS: We studied 18 tetraplegic patients, with complete motor loss between C4 and C8, and 18 healthy control subjects by measuring airway conductance, before and after inhaled ipratropium bromide. RESULTS: At baseline, the pulmonary function parameters revealed mild-to-moderate restrictive impairment in tetraplegic patients as defined by decreases in total lung capacity and predicted percent of slow vital capacity. The average baseline specific airway conductance (sGaw) was less in tetraplegic patients (0.25+/-0.11) than in the control group (0.41+/-0.10 l/s/cm H(2)O) (P<0.0001). All patients had improved post-bronchodilator sGaw >or=40% compared with only four of the 18 controls (P<0.001). The average increase for tetraplegic patients was 235% (+/-93) versus 25% (+/-24) for controls (P<0.0001). Analysis of variance for repeated measurements showed significant difference in sGaw between the control and spinal cord injury (SCI) groups (P<0.0001) following bronchodilator challenge, but found no difference for total gas volume. No difference for mean basal sGaw and bronchodilator challenge was encountered comparing tetraplegic patients using baclofen to those not using it. CONCLUSIONS: Cervical SCI patients have a reduced baseline conductance compared to controls. Marked improvement occurs after an inhaled anticholinergic drug. This behavior was not affected by the use of baclofen. The study adds support to the hypothesis of an increased cholinergic bronchomotor tone in tetraplegic patients.