Continuous noninvasive monitoring of arterial pressure using the vascular unloading technique in comparison to the invasive gold standard in elderly comorbid patients: A prospective observational study

Abstract

Background and Aims: Elderly patients aged ≥65 years represent a growing population in the perioperative field, particularly orthopedic and vascular surgery. The higher degree of age-related or comorbid-dependent vascular alterations renders these patients at risk for hemodynamic complications and likely denote a possible limitation for modern, non-invasive arterial pressure monitoring devices. The aim was to compare vascular unloading technique-derived to invasive measurements of systolic (SAP), diastolic (DAP), and mean arterial pressure (MAP) in elderly perioperative patients. Methods: This prospective observational study included patients aged ≥65 years scheduled for orthopedic and patients ≥50 years with peripheral artery disease Fontaine stage ≥ II scheduled for vascular surgery, respectively. Invasive radial artery and non-invasive finger-cuff (Nexfin system) arterial pressures were recorded before and after induction of general anesthesia and during surgery. Correlation, Bland-Altman, and concordance analyses were performed. Measurements of arterial pressure were also compared during intraoperative hypotension (MAP <70 mm Hg) and hypertension (MAP >105 mm Hg). Results: Sixty patients with orthopedic (N = 25, mean (SD) age 77 (5) years) and vascular surgery (N = 35, age 69 [10] years) were enrolled. Seven hundred data pairs of all patients were analysed and pooled bias and percentage error were: SAP:

Comparison of oscillometric, non-invasive and invasive arterial pressure monitoring in patients undergoing laparoscopic bariatric surgery – a secondary analysis of a prospective observational study

“…As there is no global definition of interchangeability, we chose two commonly accepted criteria to allow approximation: 1) the recommended Association for the Advancement of Medical Instrumentation (AAMI) criterion of a mean difference ≤ 5 mmHg and associated SD of ≤8 mmHg [ 29 ], 2) the percentage error (PE), calculated as 1.96SD of bias/[invasive arterial pressure/2] quantifying the relative differences between NIPB or Nexfin vs. IAP as an additional statistical estimate with acceptable cut-off values at 14.7% for SAP, 17.5% for DAP and 18.7% for MAP [ 30 ]. According to previous study protocols [ 19 , 28 , 31 ], sample size was determined with N = 60 study participants, followed by an intermediate evaluation. For a Bland-Altman analysis, the width w of the confidence interval for the limits of agreement (LOA) was calculated as w = 6.79•σ•1/√n, where n is number of cases and σ is the standard deviation.…”