Validation of Respiration Rate Algorithms

Continuous accurate unobtrusive respiratory rate monitoring may lead to improved patient outcomes, as respiratory rate is thought to be a sensitive marker of patient deterioration. Currently systems are not suitable for long term monitoring, particularly in ambulant patients as they are too restrictive. To ensure that our algorithms are suitable for use in a clinical context we need to demonstrate their performance not only in the optimal situation, healthy volunteers at rest, but also in more challenging situations such as where the person being monitored is moving and also in patients who have conditions which may affect their physiology in such a way that the accuracy of the respiration rate estimation may be affected.

No previous study has systematically tested algorithms deriving respiratory rate from either the ECG or the photoplethysmography (PPG) waveforms in a real -world setting.

The algorithms work by looking for changes in intervals between heartbeats and also changes in the sizes of the ECG and PPG waveforms, both of which may be caused by respiration. These changes tend to diminish with increasing age and also conditions which alter the chest movement and cardiac reflexes. Thus it is important to test our algorithms' accuracy in participants exhibiting these conditions. It is also important to ensure that the calculations of respiratory rate are accurate across a range of heart rates and respiratory rates. Our testing covers all these variables.

Study Overview

• Status: Completed
• Conditions: Respiratory Rate; Pulse Oximetry
• Intervention / Treatment: Other: Recording of 12 lead ECG; Other: Recording of lying and standing blood pressure; Other: Recording of chest wall movement; Other: Recording of heart rate variability; Other: Recording of ECG and Pulse oximeter waveform at rest; Other: Recording of ECG and Pulse oximeter waveform during exercise

• Study Type: Observational
• Enrollment (Anticipated): 130

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, SE1 7EH
    • St Thomas' Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 year and older (ADULT, OLDER_ADULT, CHILD)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Healthy volunteers and hospital outpatients

Description

Inclusion Criteria:

• Young Healthy Volunteers

  • Participant is willing and able to give informed consent for participation in the study.
  • Male or Female, aged between 18 and 40 years old.

• Older Healthy Volunteers

  • Participant is willing and able to give informed consent for participation in the study.
  • Male or Female, aged 70 years or above.

• Patients

  • Participant is willing and able to give informed consent for participation in the study.
  • Male or Female, aged 18-70 years old.
  • Participant has one of the following conditions:
  • Atrial fibrillation
  • A permanent pacemaker that is continuously active
  • Reduced chest wall movement

Exclusion Criteria:

• Young Healthy Volunteers

  • Any condition which might increase the risk of exercise testing
  • Any history of ischaemic heart disease
  • Any history of heart failure
  • Any structural heart disease (eg: valvular lesions, hypertrophic obstructive cardiomyopathy)
  • Any abnormalities on a resting ECG
  • Deep vein thrombosis diagnosed within the last 6 months or under active treatment
  • Uncontrolled hypertension (systolic blood pressure >220 mm Hg, diastolic >120 mm Hg)
  • Aortic aneurysm
  • Aortic or cardiovascular surgery within 6 months of recruitment
  • A family history of sudden cardiac death, congenital arrhythmia syndromes or cardiomyopathy
  • Autonomic dysfunction, either previously diagnosed or upon testing by the research team
  • Any condition involving the brain or spinal cord
  • Diabetes
  • Alcohol consumption > 21 units/week for women and 28 units/week for men or a history of previous alcohol dependence.
  • Acute kidney injury
  • Chronic kidney disease stage 4 or 5
  • Any condition causing hepatic dysfunction
  • Presence of a permanent pacemaker (these participants would be eligible for the pacemaker group)
  • Reduced chest wall movement (these participants would be eligible for the reduced chest movement group)
  • Any acute infection requiring antibiotic treatment within 3 months of recruitment
  • Any other surgery or illness requiring hospitalisation within 3 months of recruitment
  • Currently taking any medication with the exception of analgesics or the oral contraceptive pill.
  • Any wound or skin condition affecting the torso which may be affected by the application of adhesive ECG dots to the skin
  • Pregnancy
  • Inability to give informed consent

• Older Healthy Volunteers

  • Any diagnosed condition primarily affecting the cardiovascular or respiratory systems
  • Symptomatic autonomic dysfunction
  • Orthostatic hypotension
  • Any condition involving the brain or spinal cord
  • Diabetes
  • Alcohol consumption > 21 units/week for women and 28 units/week for men or a history of previous alcohol dependence.
  • Acute kidney injury
  • Chronic kidney disease stage 4 or 5
  • Any condition causing hepatic dysfunction
  • Presence of a permanent pacemaker
  • Chronic Obstructive Pulmonary Disease (COPD).
  • Any muscular dystrophy
  • Kyphosis
  • Scoliosis
  • Pectus excavatum
  • Any disease involving the lungs or pleura
  • Any acute infection requiring antibiotic treatment within 3 months of recruitment
  • Any other surgery or illness requiring hospitalisation within 3 months of recruitment
  • Currently taking any medication with the exception of analgesics or the oral contraceptive pill.
  • Any wound or skin condition affecting the torso which may be affected by the application of adhesive ECG dots to the skin
  • Pregnancy
  • Inability to give informed consent

• Patients

  • Any infection which would require isolation or barrier nursing according to the hospital's infection control policy
  • Any wound or skin condition affecting the torso which may be affected by the application of adhesive ECG dots to the skin
  • Requirement for any form of artificial ventilatory support, including oxygen therapy
  • More than one of the inclusion criteria. (ie: a patient may not have both atrial fibrillation and reduced chest wall movement and be eligible for this study)
  • Inability to give informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

5

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Young Healthy Volunteers; Healthy volunteers under the age of 40	Other: Recording of 12 lead ECG; Recording of 12 lead ECG; Other: Recording of lying and standing blood pressure; Recording of lying and standing blood pressure; Other: Recording of chest wall movement; Recording of chest wall movement; Other: Recording of heart rate variability; Done during deep breathing and a valsalva manoeuvre; Other: Recording of ECG and Pulse oximeter waveform at rest; For 10 mins; Other: Recording of ECG and Pulse oximeter waveform during exercise; Recording of ECG and Pulse oximeter waveform during exercise
Older healthy volunteers; Healthy volunteers over the age of 70	Other: Recording of 12 lead ECG; Recording of 12 lead ECG; Other: Recording of lying and standing blood pressure; Recording of lying and standing blood pressure; Other: Recording of chest wall movement; Recording of chest wall movement; Other: Recording of heart rate variability; Done during deep breathing and a valsalva manoeuvre; Other: Recording of ECG and Pulse oximeter waveform at rest; For 10 mins
Patients with atrial fibrillation; Patients with permanent AF	Other: Recording of 12 lead ECG; Recording of 12 lead ECG; Other: Recording of lying and standing blood pressure; Recording of lying and standing blood pressure; Other: Recording of chest wall movement; Recording of chest wall movement; Other: Recording of heart rate variability; Done during deep breathing and a valsalva manoeuvre; Other: Recording of ECG and Pulse oximeter waveform at rest; For 10 mins
Patients with a pacemaker; Patients who have an implanted pacemaker that is continually pacing	Other: Recording of 12 lead ECG; Recording of 12 lead ECG; Other: Recording of lying and standing blood pressure; Recording of lying and standing blood pressure; Other: Recording of chest wall movement; Recording of chest wall movement; Other: Recording of heart rate variability; Done during deep breathing and a valsalva manoeuvre; Other: Recording of ECG and Pulse oximeter waveform at rest; For 10 mins
Patients with restricted chest movement; Patients whose chest expansion is less than 2.5cm	Other: Recording of 12 lead ECG; Recording of 12 lead ECG; Other: Recording of lying and standing blood pressure; Recording of lying and standing blood pressure; Other: Recording of heart rate variability; Done during deep breathing and a valsalva manoeuvre; Other: Recording of ECG and Pulse oximeter waveform at rest; For 10 mins

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The coefficient of variation for each respiration rate algorithm	The algorithms to be tested are: one which calculates respiration rate (RR) from ECG only, one which calculates RR from PPG only, one which calculates RR from simultaneous ECG and PPG	5-6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The coefficient of variation for the respiration rate calculated from a second pulse oximeter	Participants will wear two different PPG monitors to assess whether PPG monitors from different manufacturers introduce artefactual changes to the PPG morphology	5-6 months

Collaborators and Investigators

• Sponsor: Guy's and St Thomas' NHS Foundation Trust
• Collaborators: University of Oxford; Engineering and Physical Sciences Research Council, UK
• Investigators: Principal Investigator: Richard Beale, MBBS, FRCA, Guy's and St Thomas' Foundation Trust

Study record dates

Study Major Dates

• Study Start: June 1, 2012
• Primary Completion (ACTUAL): February 1, 2014
• Study Completion (ACTUAL): February 1, 2014

Study Registration Dates

• First Submitted: October 20, 2011
• First Submitted That Met QC Criteria: November 11, 2011
• First Posted (ESTIMATE): November 16, 2011

Study Record Updates

• Last Update Posted (ESTIMATE): February 12, 2014
• Last Update Submitted That Met QC Criteria: February 11, 2014
• Last Verified: February 1, 2014

More Information

Terms related to this study

• Keywords: Respiration Rate; ECG; Physiology; Pulse oximetry; PPG; Photoplethysmograph
• Other Study ID Numbers: 11/LO/1667