SESSION TYPE: Heart Failure Posters
PRESENTED ON: Wednesday, October 24, 2012 at 01:30 PM - 02:30 PM
PURPOSE: A recently developed algorithm (RRoxi) provides continuous non-invasive respiratory rate from a pulse oximeter waveform. This approach is based on modulations in the photoplehtysmogram secondary to hemodynamic and autonomic changes during the respiratory cycle. Medical conditions characterized by abnormal cardiorespiratory interactions, such as congestive heart failure (CHF), may influence the fundamental modulations used by RRoxi to extract respiratory rate. We sought to determine the accuracy of RRoxi in patients with known CHF.
METHODS: With IRB approval and patient consent, we studied 12 hospitalized patients with diagnosed CHF (left ventricular ejection fraction < 30%; age: 60 ± 14.7 yr; BMI: 30 ± 5.9 kg/m2, 1 female/11 male). During an observational monitoring period of ~20 min, photoplethysmogram data were acquired from an index finger using a pulse oximetry sensor. Nasal/oral capnography waveforms were acquired simultaneously to determine a reference respiratory rate. Respiratory rate values were computed offline by RRoxi. Accuracy was calculated as root mean square deviation (RMSD) between RRoxi and the reference respiratory rate and Pearson correlation coefficients were computed to assess their relationship.
RESULTS: During the study period, RRoxi computed a respiratory rate value 93% of the time patients were monitored, yielding a total of 2,738 paired observations (RRoxi values and the capnography-base reference respiratory rate). Mean and range of the reference respiratory rate were 16.7 ± 3.0 and 10.7 to 26.1 breaths per minute, respectively. The mean difference between the measurements was 0.4 ± 1.5 breaths per minute. The accuracy of RRoxi was 1.6 breaths per minute, as measured by RMSD. The agreement between RRoxi and the reference was R2=0.76.
CONCLUSIONS: These results demonstrate that the RRoxi algorithm is accurate to within 1.6 breaths per minutes (RMSD) in patients with CHF and determined a respiratory rate during 93% of the monitoring period.
CLINICAL IMPLICATIONS: These accuracy results for RRoxi suggest that this algorithm should be clinically acceptable to provide continuous non-invasive respiratory rate monitoring in similar patients.
DISCLOSURE: Michael Mestek: Employee: Covidien Respiratory & Monitoring Soultions Scientist
Paul Addison: Employee: Covidien Respiratory & Monitoring Solutions Scientist
Anna-Maria Neitenbach: Employee: Covidien Respiratory & Monitoring Solutions Research Associate
Sergio Bergese: Other: Dr. Bergese received financial funding to complete data collection for the study.
Scott Kelley: Employee: Dr. Kelley is the Chief Medical Officer of Covidien Respiratory & Monitoring Soultions
No Product/Research Disclosure InformationCovidien, Boulder, CO