Accuracy of blood pressure monitoring in critical care : continuous non-invasive vs intra-arterial methods

Abstract

Overview of the topic: Accurate haemodynamic monitoring is crucial in intensive care units (ICUs) to improve outcomes. The invasive intra-arterial approach is considered as the gold standard in measuring blood pressure (BP) in this respective setting. However, limiting invasive procedures reduces infections and mortality. This review aims to determine whether continuous non-invasive blood pressure (CNIBP) monitoring devices are as accurate as invasive arterial methods. Research question: Amongst patients receiving critical care (Population), is continuous noninvasive blood pressure monitoring (Intervention) as accurate (Outcome) as intra-arterial blood pressure monitoring (Comparison)? Search and Appraisal Methods: A systematic search was conducted within EBSCOhost, HyDi, ProQuest, PubMed and Scopus for studies comparing the accuracy of CNIBP and invasive BP monitoring in adult patients admitted to ICU. Studies not written in English, focusing on patients undergoing surgery, or comparing intermittent BP devices with invasive catheter were excluded. Eleven key studies (four prospective cohort studies, two observational studies and five comparative studies) addressing the question were retrieved and appraised as guided by the Critical Appraisal Skills Program (CASP) checklists for cohort and diagnostic studies. Results: Three studies concluded that non-invasive monitoring of mean arterial blood pressure (MAP) is as accurate as invasive monitoring, but further studies are required for non-invasive systolic (SBP) and diastolic pressure (DBP). Two studies concluded that non-invasive MAP and DBP monitoring are as accurate as invasive readings. Four studies found that all BP readings from CNIBP devices are accurate for the respective setting, whilst two studies concluded that CNIBP devices are inaccurate. Conclusion: A definite conclusion on the accuracy of CNIBP devices in comparison to arterial catheters, cannot be reached, given the inconsistent results for non-invasive SBP and DBPs. Implications and Recommendations: The inconsistency in results necessities further research on non-invasive SBP and DBP monitoring accuracy. Such studies should include sub-populations with varying underlying conditions and readings over longer intervals and during interventions associated with BP fluctuations, particularly position turning and suctioning.