Delayed diaphragm recovery in 12 patients after high cervical spinal cord injury. A retrospective review of the diaphragm status of 107 patients ventilated after acute spinal cord injury.

STUDY

DESIGN

The functional outcome of the diaphragm after acute spinal cord injury was reviewed over a 16 year period for 107 patients who had required assisted ventilation in the acute phase.

OBJECTIVES

To quantify the incidence of recovery of diaphragm function which occurred beyond the period of acute oedema; to produce a time-related profile of this as a guide to clinicians considering phrenic nerve pacing; and to assess the value of phrenic nerve testing in predicting recovery.

SETTING

The Southport Regional Spinal Injuries Centre, Southport, England.

METHODS

Bilateral phrenic nerve and diaphragm integrity was assessed clinically, by spirometry, and by fluoroscopy without and with phrenic nerve stimulation.

RESULTS

Thirty-one per cent of all the ventilated patients (33 cases), with a level of injury between C1 and C4 (Scale A in ASIA Impairment Scale), had diaphragmatic paralysis at the time of respiratory failure. The subsequent diaphragm recovery which appeared in seven of these patients, between 40 and 393 days (mean 143), permitted weaning from ventilatory support at 93 to 430 days (mean 246) after the acute injury, with a vital capacity of over 15 ml kg(-1) at that stage. The diaphragm recovery in a further five patients, whose vital capacity remained below 10 ml kg(-1) and who could not be fully weaned, occurred significantly later, between 84 and 569 days (mean 290), P=0.053. Negative phrenic nerve tests were followed by weaning at a later interval in several cases. By contrast, one patient with an early positive phrenic stimulation test and subsequent diaphragm activity could not be weaned from the ventilator.

CONCLUSION

Twenty-one per cent of the patients with initial diaphragm paralysis were ultimately able to breathe independently after 4 and 14 months, whilst a further 15% had some diaphragm recovery. Phrenic nerve testing should be repeated at 3 monthly intervals for the first year after high tetraplegia.