Incentive spirometry inspiratory capacity changes and predictors after open heart surgery: a 5-day prospective study

Area of Science:

• Pulmonary rehabilitation
• Cardiothoracic surgery
• Respiratory physiology

Background:

• Incentive spirometry (IS) is standard for improving postoperative inspiratory capacity (ISIC) after open heart surgery (OHS).
• Predictive factors for serial ISIC changes post-OHS remain unclear.

Purpose of the Study:

• To analyze postoperative ISIC trends relative to preoperative ISIC after OHS.
• To identify predictors of ISIC changes, including patient characteristics and IS performance (inspiration volumes [ISv] and frequencies [ISf]).

Main Methods:

• Prospective study of 95 OHS patients with preop and daily ISIC measurements until POD5.
• ISv and ISf monitored electronically from POD1-POD4.
• Regression models used to identify predictors of ISIC and recovery odds.

Main Results:

• ISIC dropped to 41% on POD1, recovering to 106% by POD5.
• Higher preoperative ISIC predicted lower POD1 ISIC, while hyperlipidemia predicted higher POD1 ISIC.
• ISv significantly predicted ISIC in subsequent postoperative days, with higher ISv increasing odds of preoperative ISIC recovery by POD5. ISf showed no association.

Conclusions:

• Inspiration volumes (ISv) are crucial for IS therapy effectiveness post-OHS.
• Proposed postoperative IS therapy targets require validation via randomized controlled trials.