Summary
Professor Denny Levett presents the design and rationale for the INSPIRE trial at EBPOM 2019, a major NHS-funded pragmatic RCT evaluating inspiratory muscle training for reducing post-operative pulmonary complications. She explains that PPCs are common (5-40% incidence), increase mortality several-fold, and add over $25,000 per patient stay in costs. The ARISCAT score is used to identify high-risk patients. The trial is a three-arm design -- IMT vs sham vs usual care -- recruiting 2,500 patients across UK hospitals. Patients perform 30 breaths twice daily at 50% of maximum tolerable load for 2-8 weeks before surgery. Levett emphasizes that existing systematic reviews show a massive 50% reduction in PPCs, but supervision is critical: studies without supervision showed no benefit at all. She distinguishes IMT from incentive spirometry, which has been shown to be ineffective. The trial includes subgroup analyses for surgical specialty, nutritional status, and sex differences.
Key Points
- Post-operative pulmonary complications increase hospital costs by over $25,000 per patient stay
- ARISCAT score identifies high-risk patients using 4 patient factors and 3 procedural factors
- INSPIRE trial: 2,500-patient three-arm NHS pragmatic RCT (IMT vs sham vs usual care)
- Protocol: 30 breaths twice daily at 50% of maximum tolerable load, 2-8 weeks preoperatively
- Systematic reviews show 50% reduction in PPCs, but this drops to zero without supervision
- Incentive spirometry is ineffective for reducing PPCs -- IMT is a fundamentally different intervention
- Load progression is essential for training effect, just like progressive overload in strength training
- Trial includes subgroup analyses for surgical specialty, nutritional status, physical activity, and sex differences
Key Moments
PPCs add over $25,000 per patient stay and multiply mortality rates
Professor Levett presents data showing that post-operative pulmonary complications are several times more common than cardiac complications and increase hospital costs by over $25,000 per patient stay.
"And having a single post-op pulmonary complication increases the financial cost of your inpatient stay by just over $25,000."
INSPIRE trial design with 2,500 patients across three arms
The INSPIRE trial is a three-arm pragmatic NHS RCT testing IMT vs sham vs usual care in 2,500 high-risk surgical patients. Patients perform 30 breaths twice daily at 50% of maximum tolerable load for 2-8 weeks preoperatively.
"And it's a three-arm trial, IMT versus sham IMT versus usual care."
Supervision converts 0% to 50% reduction in complications
The most striking finding is that supervision makes the difference between zero and 50% reduction in pulmonary complications. Once-weekly supervision appears sufficient, with load progression and technique evaluation being the key elements.
"Such that you got from a 50% reduction in pulmonary complications to no reduction in pulmonary complications if it wasn't supervised at all."
