ABSTRACT
Oscillometry is increasingly adopted in respiratory clinics, but many recommendations regarding measurement settings and quality control remain subjective. The aim of this study was to investigate the optimal number of measurements and acceptable within-session coefficient of variation (CoV) in health, asthma and COPD. 15 healthy, 15 asthma and 15 COPD adult participants were recruited. Eight consecutive 30-s measurements were made using an oscillometry device, from which resistance at 5â Hz (R rs5 ) was examined. The effect of progressively including a greater number of measurements on R rs5 and its within-session CoV was investigated. Data were analysed using one-way repeated-measures ANOVA with Bonferroni post hoc test. The CoV(R rs5 ) of the first three measurements was 6.7±4.7%, 9.7±5.7% and 12.6±11.2% in healthy, asthma and COPD participants, respectively. Both mean R rs5 and CoV(R rs5 ) were not statistically different when progressively including four to eight measurements. Selecting the three closest R rs5 values over an increasing number of measurements progressively decreased the CoV(R rs5 ). In order for ≥95% of participants to fall within a target CoV(R rs5 ) of 10%, four or more, five and six measurements were needed in health, asthma and COPD, respectively. Within-session variability of oscillometry is increased in disease. Furthermore, the higher number of measurements required to achieve a set target for asthma and COPD patients may not be practical in a clinical setting. Provided technical acceptability of measurements is established, i.e. by removing artefacts and outliers, then a CoV of 10% is a marker of quality in most patients, but we suggest higher CoVs up to 15-20% should still be reportable.
Subject(s)
Arthroplasty, Replacement, Hip/methods , Coronary Artery Disease/psychology , Elective Surgical Procedures/methods , Motivation , Osteoarthritis, Hip/surgery , Preoperative Care/methods , Stress, Psychological/diagnosis , Aged , Coronary Artery Disease/etiology , Coronary Artery Disease/surgery , Humans , Myocardial Revascularization/methods , Osteoarthritis, Hip/complications , Preoperative Care/education , Stress, Psychological/complicationsABSTRACT
INTRODUCTION: We investigated the effect of postural changes on various cardiovascular parameters across gender. Twenty-eight healthy subjects (16 male, 12 female) were observed at rest (supine) and subjected to 3 interventions; head-down tilt (HDT), HDT with lower body negative pressure (HDT+ LBNP at -30âmmâHg), and head-up tilt (HUT), each for 10âminutes separated by a 10âminutes recovery period. METHODS: Measurements were recorded for heart rate (HR), standard deviation of the normal-to-normal intervals, root mean square of successive differences between the normal-to-normal intervals, heart rate variability-low frequency (LFRRI), heart rate variability-high frequency (HFRRI), low frequency/high frequency ratio (LFRRI/HFRRI), systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP), total peripheral resistance index (TPRI), stroke index (SI), cardiac index (CI), index of contractility (IC), left ventricular work index, and left ventricular ejection time. RESULTS: Across all cardiovascular parameters, there was a significant main effect of the intervention applied but there was no significant main effect of gender across all parameters. CONCLUSIONS: The results suggest that there are no specific gender differences in regards to the measured variables under the conditions of this study. Furthermore, these results suggest that in healthy subjects, there appears to be evidence that LBNP partially elicits similar cardiovascular responses to HUT, which supports the use of LBNP as an intervention to counteract the effects of central hypovolemia.
