Step oximetry test: a validation study

Abstract

IntroductionStep climbing is a potentially useful modality for testing exercise capacity. However, there are significant variations between test protocols and lack of consistent validation against gold standard cycle ergometry cardiopulmonary exercise testing (CPET). The purpose of the study was to validate a novel technique of exercise testing using a dedicated device.MethodsWe built a step oximetry device from an adapted aerobics step and pulse oximeter connected to a computer. Subjects performed lung function tests, a standard incremental cycle CPET and also a CPET while stepping on and off the step oximetry device to maximal exertion. Data from the step oximetry device were processed and correlated with standard measurements of pulmonary function and cycle CPET.ResultsWe recruited 89 subjects (57 years, 50 men). Oxygen uptake (VO2) was 0.9 mL/kg/min (95% CI −3.6 to 5.4) higher in the step test compared with the gold standard cycle CPET, p<0.001. VO2 in the two techniques was highly correlated (R=0.87, p<0.001). Work rate during stair climbing showed the best correlation with VO2 (R=0.69, p<0.0001). Desaturation during step climbing correlated negatively with diffusion capacity for carbon monoxide (r=−0.43, p<0.005). No adverse events occurred.ConclusionsThe step oximetry test was a maximal test of exertion in the subjects studied, achieving slightly higher VO2 than during the standard test. The test was safe to perform and well tolerated by the patients. Parameters derived from the step oximetry device correlated well with gold standard measurements. The step oximetry test could become a useful and standardisable exercise test for clinical settings where advanced testing is not available or appropriate.

An adapted emergency department triage algorithm for the COVID‐19 pandemic

“…21,27 SARS-CoV-2 seems to have a viral shedding pattern similar to influenza. 34,35 High viral loads have been detected in completely asymptomatic patients, calling for a minimum level of protection from respiratory droplets for all clinicians. 30,36 SARS-CoV-2 was also noted in stool in 50% of patients tested, and extensive surface contamination has been reported.…”

“…37,38 The potential for stool or fluid transmission suggest the need for concomitant contact precautions for providers within reach of a patient or contaminated surface. 30,34 The most significant controversy involving SARS-CoV-2 transmission seems to be the potential for routine airborne or aerosol spread. It is thought that the highest risk for airborne transmission occurs during aerosolizing-generating procedures, but the virus has been found to be viable in aerosols for at least 3 h. 24,34 A recent article by Santarpia et al 39 lends more support to the possibility of airborne transmission of the virus even in the absence of aerosolizinggenerating procedures.…”

“…30,34 The most significant controversy involving SARS-CoV-2 transmission seems to be the potential for routine airborne or aerosol spread. It is thought that the highest risk for airborne transmission occurs during aerosolizing-generating procedures, but the virus has been found to be viable in aerosols for at least 3 h. 24,34 A recent article by Santarpia et al 39 lends more support to the possibility of airborne transmission of the virus even in the absence of aerosolizinggenerating procedures. These data would seem to support the use of airborne precautions (N95 respirator use or equivalent) during any PUI or COVID-19-confirmed patient encounter.…”

“…These may include observation, assessment of exertional O 2 saturation, laboratory or radiographic analysis, electrocardiogram, or other testing as indicated. Although assessment of exertional O 2 saturation has not been externally validated specifically in the setting of COVID‐19, there have been a number of studies validating its use in other pulmonary pathologies 31,32 . Hypoxemia has also been shown to be independently associated with in hospital mortality in COVID‐19 patients 33 …”

What is the Efficacy and Safety of Rapid Exercise Tests for Exertional Desaturation in Covid-19: A Rapid Systematic Review&nbsp;

“…Fox et al explored the use of oximetry along with step climbing tests in the detailed assessment of pulmonary capacity, using area under the curve of a continuous oximetry reading [33]. Whilst these authors found that oximetry thus measured correlated with severity of disease and survival, such an approach is not relevant to the remote assessment of the acutely breathless or hypoxic patient.…”