The Value of Integrated Pulmonary Index Monitoring in Detecting Respiratory Events

The Value of Integrated Pulmonary Index Monitoring

Integrated Pulmonary Index (IPI) is a tool that provides numerical values on a scale of 1-10 based on physiological parameters such as peripheral oxygen saturation (SpO2), pulse rate, respiratory rate, end-tidal carbon dioxide (ETCO2). It is a valuable monitor for sedation procedures and can provide early warning during cardiorespiratory derangements.The aim of the study is to determine whether the Integrated Pulmonary Index (IPI) detects changes in ventilation status early in patients undergoing gastrointestinal endoscopy under sedation, and to determine the risk factors affecting hypoxia and severe hypoxia.

A single-center and retrospective study was conducted in 154 patients who underwent upper and lower gastrointestinal system endoscopy in the endoscopy unit between October 2018 and December 2019. Patients who were monitored by capnograph in addition to routine monitoring (ECG, noninvasive blood pressure and pulse oximetry monitoring) during the procedure in the endoscopy unit were included in the study.

Patients were administered 2 mg midazolam as premedication for 5 minutes before the procedure and propofol 1-1.3 mg/kg bolus for sedation, followed by repeated doses (10-30 mg) according to the Ramsey sedation score. All patients were given 2 lt/min oxygen via nasal cannula during the procedure. In pulse oximetry, oxygen saturation longer than 15 seconds was defined as less than 92% hypoxia, and below 85% was defined as severe hypoxia.

IPI value was measured with Smart Capnography™, Microstream® Integrated Pulmonary Index device. According to the capnographic information obtained from the patients and preserved in the capnograph disc memory, the planned findings in the study are as follows:

1. Number of hypoxic events observed in patients (SaO2 value below 92% over 15 seconds)
2. Number of severe hypoxic events observed in patients (SaO2 value below 85%)
3. Apnea episodes observed in patients (observation of a straight line longer than 15 seconds on the capnograph, absence of respiratory activity)
4. Time from apnea to development of hypoxia and severe hypoxia in patients who develop hypoxia and severe hypoxia following apnea
5. Time between IPI=1, IPI<7, EtCO2=0 and hypoxia and severe hypoxia.

Inclusion Criteria:

• Patients monitored by capnograph
• ASA I-III
• Patients who underwent an elective endoscopic procedure

Exclusion Criteria:

• Patients who do not have capnograph monitoring or whose capnography records are missing
• Emergency endoscopic intervention (GIS bleeding, trauma, etc.)
• ASA IV-V
• Patients with pre-procedure SaO2 value below 90%, systolic blood pressure below 90 mmHg, heart rate below 50 beats/minute