A new study suggests that patients in the post-anesthesia care unit (PACU) with a high risk for respiratory adverse events (RAEs) should be monitored with both noninvasive end-tidal carbon dioxide (etCO2) and pulse oximetry using the Integrated Pulmonary Index (IPI). According to Hiroshi Morimatsu, MD, PhD, pulse oximetry is a commonly used method for monitoring respiratory failure, but there is an increasing interest among clinicians in the functionality of measuring end-tidal CO2 after intubation, which is currently not done in the postoperative setting, as indicated on an Anesthesiology News report.

Morimatsu and his colleagues conducted a retrospective study to test the efficacy of the IPI, a 10-point scale that combines a patient’s end-tidal CO2, pulse oximetry, respiratory rate and pulse rate, for predicting RAEs in the PACU. The study included 163 patients with a high risk for hypoventilation in the PACU after general surgery. Patients were considered high risk if they were older than 75 years of age or had a body mass index greater than 28 kg/m2. The patients were enrolled at two centers from October 2014 to February 2015.

Overall, there were 11 patients who suffered an RAE, with one patient requiring operation and treatment in the intensive care unit. The PACU stay for patients with an RAE was almost double the time of patients without an RAE (97.2 ± 44.4 vs. 51.8 ± 27.2 minutes; P<0.0001), as noted on the Anesthesiology News report. The researchers also found lower initial IPI and SpO2 measurements for the RAE group compared with the non-RAE group (6.5 ± 2.5 vs. 9.1 ± 1.3; P<0.0001 and 96.6% ± 4.4% vs. 98.3% ± 1.9%; P=0.0147, respectively).

According to Anesthesiology News, the researchers concluded that IPI has better sensitivity and specificity, making it superior to pulse oximetry alone for predicting the onset of RAE after surgery. Morimatsu says, “SpO2 can give you the oxygenation—if it’s good or not—but we cannot assess the respiration. IPI can give us a number, and this number is very easy to understand: 10 is OK; 1 is very bad.”

Morimatsu explains that currently there are no set guidelines for the IPI scores and suggests clinicians pay more attention to any patient who scores less than 7. In addition, he says further research is needed and he is looking to conduct a larger multicenter study that will look at other types of patients. The findings of the study were presented at the 2015 annual meeting of the American Society of Anesthesiologists.

Source: Anesthesiology News