Background and Goal of Study: The Integrated Pulmonary Index (IPI) is based on sophisticated algorithm integrating the real time interactions of four parameters (peripheral oxygen saturation, end-tidal CO2, respiratory rate and pulse rate) into a single index value. The aim of this study was to explore the value of IPI after coronary artery bypass grafting (CABG).
Materials and Methods: Twenty-three adult patients (62±6 yrs.) who underwent elective off-pump CABG were enrolled into a prospective study. IPI was measured and displayed by Capnostream™ monitor (Oridion, Israel). All the patients were divided into two groups according to the postoperative IPI value: optimal IPI (IPIOPT > 8, n = 11) and suboptimal IPI (IPISUB ≤ 8, n = 12). Blood gases, ventilatory and hemodynamic parameters were registered after the transfer to ICU, before and after spontaneous breathing trial (SBT), at 1 hr, 6 hrs, and 12 hrs after intervention. The groups were compared using Mann-Whitney U-test; discrete data were analysed using □2-test. The correlations were assessed using Spearman rho. p < 0.05 was considered statistically significant.
Results and Discussion: The value of IPI after the transfer to ICU correlated with IPI at 12 hrs after the intervention (rho = 0.51; p = 0.02). Moreover, values of IPI after, but not before, the standard 30-min SBT were associated with IPI values at 1 hr after extubation (rho = 0.70; p = 0.001). We found that patients of the IPISUB group were smokers more frequently that those of the IPIOPT group (p = 0.01). The smokers also tended to have lower IPI at 12 hrs after intervention (p = 0.08); PaO2/FiO2 ratio did not differ between the groups.
Conclusions: During early postoperative period after CABG, IPI can predict the success of tracheal extubation and reflects the changes in respiratory function. Thus, IPI may be a valuable adjunct to the routine perioperative monitoring, facilitating early detection of respiratory problems.