Monitoring ventilation accurately is a technically challenging, yet indispensable aspect of patient care in the intra- and post-procedural settings. A new prototypical device known as the Linshom Respiratory Monitoring Device (LRMD) has been recently designed to non-invasively, inexpensively, and portably measure respiratory rate. The purpose of this study was to measure the accuracy and variability of LRMD measurements of respiratory rate relative to the measurement of capnography. In this prospective study, participants were enrolled and individually fitted with a face mask monitored by the LRMD and capnography. With a baseline oxygen flow rate and digital metronome to pace their respiratory rate, the participants were instructed to breathe at 10 breaths per minute (bpm) for 3 min, 20 bpm for 3 min, 30 bpm for 3 min, 0 bpm for 30 s, and resume regular breathing for 30 s. Both sensors were connected to a computer for continuous temperature and carbon dioxide waveform recordings. The data were then retrospectively analyzed. Twenty-six healthy volunteers, mean (range) age 27.8 (23–37) and mean (range) BMI 23.1 (18.8–29.2) kg/m2 were recruited. There were 15 males (57.7%) and 11 females (42.3%). After excluding 3 subjects for technical reasons, 13,800 s of breathing and 4,140 expiratory breaths were recorded. Throughout the protocol, the average standard deviation (SD) for the LRMD and capnography was 1.11 and 1.81 bpm, respectively. The overall mean bias (±2SD) between LRMD and capnography was −0.33 (±0.1.56) bpm. At the lowest and intermediate breathing rates reflective of hypoventilation and normal ventilation, the LRMD variance was 0.55 and 1.23 respectively, compared to capnography with 5.54 and 7.47, respectively. At higher breathing rates indicative of hyperventilation, the variance of the test device was 4.52, still less than that of capnography at 5.73. This study demonstrated a promising correlation between the LRMD and capnography for use as a respiratory rate monitor. The LRMD technology may be a significant addition to monitoring vital signs because it offers a minimally intrusive opportunity to detect respiratory rate and apnea, without expensive or complex anesthetic equipment, before the need for life-saving resuscitation arises.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Jones JG, Sapsford DJ, Wheatley RG. Postoperative hypoxemia: mechanisms and time course. Anesthesia. 1990;45:566–73.
Chiumello D, Chevallard G, Gregoreti C. Non-invasive ventilation in postoperative patients: A systematic review. Intensive Care Med. 2011;37(6):918–29.
Taylor S, Kirton OC, Staff I, Kozol RA. Postoperative day one: a high risk period for respiratory events. Am J Surg. 2005;190:752–6.
McAlister FA, Bertsch K, Man J, et al. Incidence of and risk factors for pulmonary complications after nonthoracic surgery. Am J Respir Crit Care Med. 2005;171:514–7.
Hall JC, Tarala RA, Hall JL, Mander J. A multivariate analysis of the risk of pulmonary complications after laparotomy. Chest. 1991;99:923.
Schein RM, Hazday N, Pena M, Ruben BH, Sprung CL. Clinical antecedents to in-hospital cardiopulmonary arrest. Chest. 1990;98:1388–92.
Mailey J, Digiovine B, Baillod D, Gnam G, Jordan J, Rubinfeld I. Reducing hospital standardized mortality rate with early interventions. J Trauma. Nursing. 2006;13:178–82.
Lawrence VA, Hilsenbeck SG, Mulrow CD, et al. Incidence and hospital stay for cardiac and pulmonary complications after abdominal surgery. J Gen Intern Med. 1995;10:671.
Practice guidelines for post anesthetic care. A report by the American Society of Anesthesiologists Task Force on postanesthetic care. Anesthesiology. 2002;96:742–72.
World Health Organization. Fourth Programme report, 1988–1989: ARI programme for control of acute respiratory infections. Geneva: WHO; 1990. p. 31.
Semmes B, Tobin M, Snyder J, Grenvik A. Subjective and objective measurement of tidal volume in critically ill patients. Chest. 1985;78:577–9.
Lovett P, Buchwald J, Sturmann K, Bijur P. The vexations vital: Neither clinical measurements by nurses nor an electronic monitor provides accurate measurements of respiratory rate in triage. Ann Emerg Med. 2005;45(1):68–76.
Gaucher A, Frasca D, Mimoz O, Debaene B. Accuracy of respiratory rate monitoring by capnometry using the Capnomask in extubated patients receiving supplemental oxygen after surgery. Br J Anaesth. 2012;108(2):316–20.
Hogan J. Why don’t nurses monitor the respiratory rates of patients? Br J Nurs. 2006;15(9):489–92.
Mellin-Olsen J, Staender S, Whitaker DK, Smith AF. The Helsinki declaration on patient safety in anaesthesiology. Eur J Anaesthesiol. 2010 Jul;27(7):592–7. doi:10.1097/EJA.0b013e32833b1adf.
Vimlati L, Gilsanz F, Goldik Z. Quality and safety guidelines of postanaesthesia care: working party on post anaesthesia care (approvedby the European board and section of anaesthesiology, Union Europeenne des MedecinsSpecialistes). Eur J Anaesthesiol. 2009;26:715–21.
Standards for Basic Anesthetic Monitoring. ASA House of Delegates on October 21, 1986, last ammended on October 20, 2010, and last affirmed on October 28, 2015.
Ramsay MA, Usman M, Lagow E, Mendoza M, Untalan E, De Vol E. The accuracy, precision, and reliability of measuring ventilatory rate and detecting ventilatory pause by rainbow acoustic monitoring and capnometry. AnesthAnalg. 2013;117(1):69–75.
Nassar BS, Schmidt GA. Capnography during Critical Illness. Chest. 2016;149(2):576–85.
Babaeizadeh S. Cost efficient accurate monitoring of respiration rate using ECG. Computing in Cardiology Conference, 2015. 18 February 2016. doi:10.1109/CIC.2015.7411084.
Mimoz O, Benard T, Gaucher A, Frasca D, Debaene B. Accuracy of respiratory rate monitoring using a non-invasive acoustic method after general anesthesia. British. J Anesth. 2012;108(5):872–5.
Jovanov E, Raskovic D, Hormigo R. Thermistor-based breathing sensor for circadian rhythm evaluation. Biomed Sci Instrument Conf Proc. 2001;37:493–7.
Nilsson L, Johansson A, Kalman S. Monitoring of respiratory rate in postoperative care using a new photoplethysmographic technique. J Clin Monit Comput. 2000;16(4):309–15.
Ono Y, Mohamed D, Kobayashi M, Jen C. Piezoelectric membrane sensor and technique for breathing monitoring. Proceedings of IEEE Ultrasonics Symposium Conference Proceedings 2008, 795–798.
Chen Z, Lau D, Teo J, Ng S, Yang X, Kei P. Simultaneous measurement of breathing rate and heart rate using a microbend multimode fiber optic sensor. J Biomed Opt. 2014;19(5):057001.
Boccanfuso L, O’Kane J. Remote measurement of breathing rate in real time using a high precision, single-point infrared temperature sensor. Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics; 2012, 1704–1709.
Zhang Z, Zheng J, Wu H, Wang W, Wang B, Liu H. Development of a respiratory inductive plethysmography module supporting multiple sensors for wearable systems. Sensors. 2012;12(10):13167–84.
Egleston CV, Ben Aslam H, Lambert MA. Capnography for monitoring non-intubated spontaneously breathing patients in an emergency room setting. J AccidEmerg Med. 1997;14:222–4.
Hok B, Wiklund L, Henneberg S. A new respiratory rate monitor: development and initial clinical experience. J Clin Monit Comput. 1993;10(2):101–7.
Manczur T, Greenough A, Hooper R, Allen K, Latham S, Price JF, Rafferty GF. Tidal breathing parameters in young children: comparison of measurement by respiratory inductance plethysmography to a facemask, pneumotachograph system. Pediatr Pulmonol. 1999;28(6):436–41.
Larsson C, Staun P. Evaluation of a new fiber-optical monitor for respiratory rate monitoring. J Clin Monit Comput. 1999;15(5):295–8.
Van Loon, K. Breteler MJ, Van Wolfwinkel L, RheineckLeyssius AT, Kossen S, Kalkman CJ, Van Zaane B, Peelen LM. Wireless non-invasive continous respiratory monitoring FMCW radar: a clinical validation study.
Hers, V, Corbugy D, Joslet I, Hermant P, Demarteau J, Delhougne B, Vandermoten G, Hermanne, JP. New Concept using Passive Infrared technolgoy for a contactless detection of breathing movement: a pilot study involving a cohort of 169 adult patients. J ClinMonitComput. 2013; 27(5): 521–529.
Sathyamoorthy M, Lerman J, Feldman D, Feldman R, Moser J, Feldman U. Linsholm: A New Respiratory Monitor. ASA Abstract. San Francisco, USA, 2013: A5032.
Lerman J, Feldman D, Feldman R, Moser J, Feldman L, Sathyamoorthy M, Deitch K, Feldman U. Linshom respiratory monitoring device: a novel temperature-based respiratory monitor. Can J Anaesth. 2016 Oct;63(10):1154–60.
Standards for Basic Anesthetic Monitoring. American Society of Anesthesiologists Committee for Standards and Practice Parameters. Affirmed on 28 October 2015.
Practice guidelines for postanesthetic care. An updated report by the ASA Task Force on post anesthetic care. Anesthesiology. 2014;118(2):1–17.
National Association of State EMS Officials Medical Directors Council. National Model EMS Clinical Guidelines, 23 Oct 2014.
Blankush JM, Freeman R, McIlvane J, Tran T, Nassani S, Leitman IM. Implementation of a novel postoperative monitoring system using automated modified early warnign scores (MEWS) incorporating end-tital capnography. J Clin Monit Comput 2016. Epub ahead of print.
Helfand M, Christensen V, Anderson J. Technology Assessment: Early Sense for Monitroing vital Signs in Hospitalized Patients. VA Evidence-based Synethesis Program Evidence Briefs [Internet]. Washington (DC): Department fo Veterans Affairs (US); 2011.
Tang K, Chiu J, Low E. Airway and ventilator equipment in field anesthesia: what’s new? Mil Med. 2004;169(5):342–8.
Funding for this study was provided by internal department funds.
Conflict of interest
Drs. Bhavani Kodali and Richard D. Urman received funding from Medtronic for unrelated research. Dr. James H. Philip has a financial interest in Respiratory Motion Incorporated. The remaining authors report no conflicts of interest.
Research Involving Human Participants
Institutional Review Board approval was obtained for subject recruitment and analysis of the data. The authors do not know of any ethical issues to declare.
Informed consent was obtained from all study participants prior to study.
About this article
Cite this article
Preiss, D., Drew, B.A., Gosnell, J. et al. Linshom thermodynamic sensor is a reliable alternative to capnography for monitoring respiratory rate. J Clin Monit Comput 32, 133–140 (2018). https://doi.org/10.1007/s10877-017-0004-4
- Respiratory rate
- End-tidal carbon dioxide