Patient Monitoring & DIAGNOSTIC Systems Learning Module
Patient monitoring
Intermittent vs continuous monitoring
When requiring medical assistance, a patient (if conscious) will typically have to answer simple questions and vital signs will be checked. The UK’s National Health Service (NHS) recommends checking vital signs and/or national early warning score (EWS) on the ward at least every 12 hours, with an increased frequency for patients with an elevated EWS (Royal College of Physicians, 2017). Continuous monitoring and recording of vital signs is recommended for those with an aggregate NEW score of 7 or more. You can find out more on the NEW scoring system by clicking on the chart below.
Early warning scores give a numerical aggregate score gathered from certain physiological parameters but cannot alert for deterioration between measurements. Indeed, one has to keep in mind that a normal reading taken at one point in time represents only that one point in time – an abnormal spike might have happened a moment before the examiner got to the patient or might happen a moment after they leave the patient. Several studies have shown that continuous vital sign monitoring has the potential to improve the detection of deteriorating patients and thus save lives.
A blind study by Sun et al. (Anesthesia and Analgesia, 2015) continuously monitored oxygen saturation of patients and compared the detection of aberrant events (hypoxemic thresholds) with the nursing staff’s observational rounds. They found that these rounds only detected about 10% of the aberrant events detected by the vital sign monitor in continuous mode. Another blind study by Turan et al. (Anesthesiology, 2019) used a continuous noninvasive monitor to record blood pressure at a 1-min interval for 48 hours. Nursing staff depended on their routine vital-sign assessments for blood pressure measurements. As a result, routine monitoring missed half of the patients having an episode of hypotension and 73% of patients experiencing periods of severe hypertension when compared on the data collected by the continuous noninvasive vital sign monitor.
A recent systematic review by Downey et al. (International Journal of Nursing Studies, 2018) on intermittent vs continuous vital signs monitoring included 24 studies that reported outcomes on a total of 40,274 patients and 59 ward staff in nine countries. Benefits in terms of critical care use and length of hospital stay were reported in the majority of the studies, and 3 studies showed cost-effectiveness.
Patient monitoring
The human body never stops to try and maintain its homeostasis, a very dynamic self-regulating process controlling physiological variables that keeps us alive. Changes in vital signs provide precious insight about what is going on internally, which is why they are intermittently or continuously monitored, depending on the potential vulnerability of the patient. These include blood pressure, respiratory rate (considered to be the best predictor of patient deterioration (Churpek et al., 2012)), body temperature and heart rate. Vital signs can be checked using separate diagnostic tools such as a thermometer, a blood pressure monitor and a pulse oximeter, or they can be checked using a vital sign monitor integrating several diagnostic tools. The Riester RVS-100 for example is an advanced vital sign monitor. This all-in-one solution allows the caregiver to check all vital signs using one device: the measurements are recorded, stored and displayed on the monitor.
Intermittent vs continuous monitoring
When requiring medical assistance, a patient (if conscious) will typically have to answer simple questions and vital signs will be checked. The UK’s National Health Service (NHS) recommends checking vital signs and/or national early warning score (EWS) on the ward at least every 12 hours, with an increased frequency for patients with an elevated EWS (Royal College of Physicians, 2017). Continuous monitoring and recording of vital signs is recommended for those with an aggregate NEW score of 7 or more. You can find out more on the NEW scoring system by clicking on the chart below.
Early warning scores give a numerical aggregate score gathered from certain physiological parameters but cannot alert for deterioration between measurements. Indeed, one has to keep in mind that a normal reading taken at one point in time represents only that one point in time – an abnormal spike might have happened a moment before the examiner got to the patient or might happen a moment after they leave the patient. Several studies have shown that continuous vital sign monitoring has the potential to improve the detection of deteriorating patients and thus save lives.
A blind study by Sun et al. (Anesthesia and Analgesia, 2015) continuously monitored oxygen saturation of patients and compared the detection of aberrant events (hypoxemic thresholds) with the nursing staff’s observational rounds. They found that these rounds only detected about 10% of the aberrant events detected by the vital sign monitor in continuous mode. Another blind study by Turan et al. (Anesthesiology, 2019) used a continuous noninvasive monitor to record blood pressure at a 1-min interval for 48 hours. Nursing staff depended on their routine vital-sign assessments for blood pressure measurements. As a result, routine monitoring missed half of the patients having an episode of hypotension and 73% of patients experiencing periods of severe hypertension when compared on the data collected by the continuous noninvasive vital sign monitor.
A recent systematic review by Downey et al. (International Journal of Nursing Studies, 2018) on intermittent vs continuous vital signs monitoring included 24 studies that reported outcomes on a total of 40,274 patients and 59 ward staff in nine countries. Benefits in terms of critical care use and length of hospital stay were reported in the majority of the studies, and 3 studies showed cost-effectiveness.
Wireless vital sign monitoring
The appellation “wireless vital sign monitoring” is generally used to describe a compact and portable device used to monitor vital signs or sensors able to wirelessly transmit their readings to a vital sign monitor. Most commercial biosensors and wearable sensors (necklaces, bracelets, etc.) have Bluetooth capability which means that no Internet connection or physical connection is required unless the data collected is to be sent to a third party location. In today’s connected world, a vital sign monitor no longer needs to take the form of a complex medical device – it can be as simple as a software in a personal digital assistant (PDA), a laptop or a desktop computer. This opens the door to remote monitoring and has the potential to facilitate continuous monitoring and improve the level of care.
Alparslan Turan, Christine Chang, Barak Cohen, Wael Saasouh, Hani Essber, Dongsheng Yang, Chao Ma, Karen Hovsepyan, Ashish K. Khanna, Joseph Vitale, Ami Shah, Kurt Ruetzler, Kamal Maheshwari, Daniel I. Sessler; Incidence, Severity, and Detection of Blood Pressure Perturbations after Abdominal Surgery: A Prospective Blinded Observational Study. Anesthesiology 2019; 130:550–559 doi: https://doi.org/10.1097/ALN.0000000000002626
C.L. Downey, S. Chapman, R. Randell, J.M. Brown, D.G. Jayne, The impact of continuous versus intermittent vital signs monitoring in hospitals: A systematic review and narrative synthesis, International Journal of Nursing Studies, Volume 84, 2018, Pages 19-27, ISSN 0020-7489, https://doi.org/10.1016/j.ijnurstu.2018.04.013.
David Kaputa, David Price, John D. Enderle; A Portable, Inexpensive, Wireless Vital Signs Monitoring System. Biomed Instrum Technol 1 July 2010; 44 (4): 350–353. doi: https://doi.org/10.2345/0899-8205-44.4.350
Discover how telehealth and remote monitoring is transforming the NHS (healtheuropa.eu)
Liverpool CCG ramps up telehealth expansion with Docobo (digitalhealth.net)
L.M. Posthuma, C. Downey, M.J. Visscher, D.A. Ghazali, M. Joshi, H. Ashrafian, S. Khan, A. Darzi, J. Goldstone, B. Preckel, Remote wireless vital signs monitoring on the ward for early detection of deteriorating patients: A case series, International Journal of Nursing Studies, Volume 104, 2020, 103515, ISSN 0020-7489, https://doi.org/10.1016/j.ijnurstu.2019.103515.
Remote monitoring system to enhance patient care – NHSX
Sun, Zhuo MD*; Sessler, Daniel I. MD*†; Dalton, Jarrod E. PhD*; Devereaux, PJ MD, PhD†‡; Shahinyan, Aram MD*; Naylor, Amanda J. BA*; Hutcherson, Matthew T. BS*; Finnegan, Patrick S. BA, NREMT-B*; Tandon, Vikas MD‡; Darvish-Kazem, Saeed MD‡§; Chugh, Shaan MD‡; Alzayer, Hussain BSc, MD‡‖; Kurz, Andrea MD* Postoperative Hypoxemia Is Common and Persistent, Anesthesia & Analgesia: September 2015 – Volume 121 – Issue 3 – p 709-715 doi: 10.1213/ANE.0000000000000836
Tsuneaki Kenzaka, Masanobu Okayama, Shigehiro Kuroki, Miho Fukui, Shinsuke Yahata, Hiroki Hayashi, Akihito Kitao, Daisuke Sugiyama, Eiji Kajii, Masayoshi Hashimoto, Importance of Vital Signs to the Early Diagnosis and Severity of Sepsis: Association between Vital Signs and Sequential Organ Failure Assessment Score in Patients with Sepsis, Internal Medicine, 2012, Volume 51, Issue 8, Pages 871-876, Released April 15, 2012, Online ISSN 1349-7235, Print ISSN 0918-2918, https://doi.org/10.2169/internalmedicine.51.6951