How consistently do RNs perform the procedure of collecting specimens for measurement of gastric pHi and CO2?

Gastric Tonometry is an important tool being used more frequently in the Intensive Care Unit (ICU). Tonometry is used to collect normal saline which has equilibrated with the stomach contents and is used in combination with a sample of arterial blood to calculate intragastric PaCO2 and intramucosal pH (pHi). These values are indicative of gastric perfusion. Correct performance of each of the 5 procedural steps to instill and then collect the normal saline is paramount for accuracy of the CO2 and pHi results. The aim of this study was to examine how consistently nurses perform the procedure. Study participants comprised two groups of 15 registered nurses (RNs) chosen at random from the nurses employed in the ICU at Liverpool Hospital (NSW, Australia). The first group of RNs were asked to answer a questionnaire before and after performing the tonometry procedure under simulated conditions. The second group were asked to perform the tonometry procedure only. Each participant was observed by one of the researchers whilst performing all of the procedural steps. Regardless of critical care experience of participants or the number of years since registration a s a nurse, error rates in performing the specimen collection/procedure were as high as 34%. This study is designed to examine the previously unaddressed area of how accurately nursing staff follow systematic instructions to collect the mucosal sample.