DIAPHRAGM FUNCTION IN PATIENTS WITH CERVICAL CORD INJURY OR PRIOR POLIOMYELITIS INFECTION

Diaphragm function was evaluated in cervical cord injury patients (CCI ), 1-3 years after injury (CCI1-3) and 10 years or more after injury ( CCIgreater than or equal to 10), as well as in a group of prior poliom yelitis infection patients (PPI), requiring intermittent positive pres sure ventilation (IPPV) for about 6 h per night. Measurements included transdiaphragmatic pressure swings (Delta Pdi) at rest, during maxima l inspiratory efforts against closed airways (Delta Pdi(max)) and duri ng sniff manoeuvres (ie maximal inhalation through the nose, Delta Pdi (sniff)), vital capacity normalized to age and height (VC%pred), tidal volume (Vt), relative inspiratory time (Ti/Ttot), breathing frequency (f(b)), and the tension-time index of the diaphragm (TTdi = Delta Pdi /Delta Pdi(max) x Ti/Ttot). The median VC%pred was 50% in the CCI1-3 g roup and 57% in the CCIgreater than or equal to 10 group, but only 28% in the PPI group. Delta Pdi(max) values were similar for the CCI1-3 ( 11.8 kPa) and CCIgreater than or equal to 10 (11.9 kPa) groups, but we re lower (7.1 kPa) in the PPI group. Due to the reduction in Delta Pdi (max), the PPI group had higher Delta Pdi/Delta Pdi(max) values than t he CCI groups, however, the TTdi was similar amongst the different gro ups studied. A submaximal exercise test in five cervical cord injury p atients and in five polio patients with similar Delta Pdi(max), Delta Pdi(sniff) and TTdi values at rest revealed clear group differences wi th respect to force development, in that CCI patients showed significa nt increases in TTdi, while PPI demonstrated only minor changes. In CC I patients, an increase in ventilation was accompanied by an increase in Delta Pdi/Delta Pdi(max) while in contrast, the PPI patients showed no increase in Delta Pdi/Delta Pdi(max). We conclude that CCI patient s, both recently and previously injured, have a similar maximal inspir atory force and are less impaired than the PPI patients. The TTdi at r est is similar in all groups, but the PPI patients react to inspirator y loads with little increases in TTdi, while the CCI patients increase their TTdi above fatiguing (0.15) levels. The different behaviours ma y be linked to loss of sensory pathways in the CCI patients.