Feasibility of Tidal Volume Strategies in Subacute Cervical Spinal Cord Injury: A Pilot Randomized Trial.

Abstract

Objectives: To assess feasibility of comparing moderate-low (8-10 mL/kg predicted body weight [PBW]) tidal volume (mLVT) versus moderate-high (14-16 mL/kg PBW) tidal volume (mHVT) strategies, and to generate exploratory data on respiratory outcomes and systemic inflammation in individuals with subacute cervical spinal cord injury (SCI) requiring mechanical ventilation (MV).

Methods: In a randomized comparative effectiveness pilot trial at 2 inpatient rehabilitation hospitals, adults (≥18 years) with traumatic cervical SCI on MV were randomized to mLVT or mHVT. The primary outcome was feasibility (recruitment, adherence, retention). Secondary outcomes included pneumonia, other pulmonary complications, ventilator-free days (VFDs), and weaning success at discharge. Exploratory outcomes were changes in inflammatory markers (IL-6, IL-8, TNF-α, IL-1β). Bayesian regression models estimated relative risks (RR) and posterior probabilities.

Results: Thirty participants (15 per group) were enrolled. Recruitment and retention rates were 76% and 100%. VT adherence was higher in mLVT (87% vs. 73%). Exploratory analyses suggested estimated risks of pneumonia and pulmonary complications in mLVT were RR 1.71 (95% credible interval [CrI] 0.64, 4.75; posterior probability = 0.86) and RR 1.57 (CrI 0.76, 3.33; posterior probability = 0.89), respectively. Median VFDs were greater in mLVT (12 vs. 7 days; posterior probability = 0.70). Weaning success was similar (73%). Trends in inflammatory markers favored mLVT, with greater reductions in IL-6, IL-8, and TNF-α.

Conclusions: This trial supports the feasibility of comparing mLVT and mHVT strategies in subacute cervical SCI. Findings should be interpreted as hypothesis-generating and primarily serve to inform outcome selection and sample size calculations for a definitive trial.