The role of vital signs in preventing postoperative hospital crises

01.07.24 09:38 PM Comment(s) By America

By América Torres
Monitoring vital signs prevents postoperative crises
Photo: Freepik

Vital signs monitors are tools that can make a significant difference in postoperative patient outcomes. About half of adverse events occur in general care areas. However, acute cardiorespiratory events do not occur unexpectedly. Up to 60% of patients show one or more abnormal vital signs up to 4-6 hours before experiencing cardiac arrest. Therefore, it is crucial for healthcare professionals responsible for them to early detect changes in cardiorespiratory physiology to take preventive and/or therapeutic measures that favor a satisfactory recovery.


Hence the need for physicians and nurses to have reliable vital signs monitors that help them monitor patients without increasing their workload. This article addresses the advantages of closely monitoring patients, emphasizing the benefits of trend analysis of their vital signs to prevent fatal outcomes.


Disadvantages of intermittent vital signs monitoring

Generally, in hospital wards, nurses check patients' vital signs with several hours between each check (approximately every 2 to 4 hours). Due to the intermittent nature of these checks, there is a risk of overlooking abnormalities in vital signs that typically precede serious adverse events.

The study by Zhuo Sun et al., titled "Postoperative hypoxemia is common and persistent: A prospective blinded observational study", noted that when nurses check vital signs every 4 hours, they may miss up to 90% of hypoxemia events. Similarly, "Incidence, severity, and detection of blood pressure perturbations after abdominal surgery: A prospective blinded observational study", states that this practice also leads to the failure to detect approximately 50% of hypotensive events. 

Other studiessuggest that intermittent monitoring of patients' vital signs is a key factor contributing to failure in rescue efforts. Therefore, other authors conclude 

that continuous monitoring of vital signs could help improve postoperative outcomes. Furthermore, episodes of respiratory depression have been reported in up to 46% of patients receiving opioids in general care wards, which can progress to respiratory arrest if undetected. According to the document "Preventing respiratory depression", continuous monitoring could prevent many catastrophic respiratory events.

Vital signs monitoring with a focus on trend analysis

Continuous monitoring can undoubtedly be very beneficial in all hospital areas, as many in-hospital cardiac arrests occur in general or medical wards. An audit conducted in 144 hospitals across the UK reported in-hospital cardiac arrests in 23,554 adult patients. Many of these events were observed in medical patients (over 80%) and occurred in the wards (57%).

The issue is that many patients do not deteriorate unexpectedly; rather, healthcare professionals suddenly notice their deteriorating condition. A study compared the Modified Early Warning Score (based on the aggregation of vital signs) in ward patients who did or did not have a cardiac arrest. The Modified Early Warning Score was significantly different not only 30 minutes before but also 8, 24, and even up to 48 hours before the arrest, despite both groups having the same Modified Early Warning Score at the time of ward admission.

Other studies have shown that vital signs often exhibit abnormalities hours before cardiac arrest or ICU admission. These studies highlight the fact that clinical deterioration is often progressive. Therefore, continuous monitoring, with a focus on trend analysis of patients' vital signs, can help detect abnormal clinical trajectories at an early stage and could reduce the number of severe adverse events.

Critical vital signs

Early warning scores combining various vital signs are better predictors of severe adverse events than individual vital signs alone. Thanks to connectivity advancements, there are now vital signs monitors that automatically calculate trends, providing healthcare professionals with a comprehensive view of the patient's condition. Some of the vital signs that carry significant weight in outcomes include:

Heart Rate and ECG. During the postoperative period, heart rate (HR) can increase due to various factors such as stress, pain, atrial fibrillation, sepsis, and bleeding. Increased HR is not a specific marker but an indicator of clinical deterioration. In a cohort study conducted in 360 hospitals in the United States by Lyons et al., abnormal heart rate was responsible for 21.6% of 402,023 rapid response team activations.
Continuous electrocardiographic monitoring also benefits patients. According to the document "The International Surgical Outcomes Study group. Global patient outcomes after elective surgery: Prospective cohort study in 27 low-, middle-, and high-income countries", cardiac arrhythmia was the third most common postoperative complication.


Blood Pressure. Monitoring blood pressure allows for detection of both hypertensive and hypotensive events. While the impact of postoperative hypertension has not been confirmed, data indicate that postoperative hypotension is associated with adverse events such as acute kidney injury, myocardial infarction, and death. The study by Lyons et al. reports that hypotension accounted for 15.7% of rapid response team activations.

Oxygen Saturation. The study by Lyons et al. also mentions that a decrease in SpO2 was responsible for 21.2% of rapid response team activations. In patients receiving oxygen, SpO2 can be a late indicator of respiratory complications.

Respiratory Rate. Respiratory rate (RR) can be abnormal in many clinical situations, including respiratory complications, sepsis, and metabolic disorders (such as acidosis). In the study by Lyons et al., out of a total of 59,720 rapid response team activations due to RR abnormalities, 71% were caused by tachypnea and 29% by bradypnea.

According to "Multicenter Comparison of Machine Learning Methods and Conventional Regression for Predicting Clinical Deterioration on the Wards", which included over 260,000 ward patients and used machine learning methods to predict clinical deterioration, RR was a decisive factor in the predictive algorithm, followed by heart rate, systolic blood pressure, and SpO2.

Preventable deaths

Unexpected deaths in hospital wards are frequent because patients' clinical deterioration can go unnoticed for hours, due to the low nurse-to-patient ratio and the time intervals between vital sign monitoring.

Fortunately, there are reliable solutions that facilitate continuous monitoring, and several studies have reported a decrease in ICU admissions, rescue interventions, cardiac arrests, and deaths following their implementation.

Healthcare professionals require monitors that provide reliable alarms, trend information, and even remote monitoring capabilities. There are devices that can facilitate their work and significantly enhance patient care, such as the Tranquility IIvital signs monitor from SCHILLER. This vital signs monitor features the Central View function, which allows networking (wireless or wired) of 4 to 32 Tranquility II monitors. This enables simultaneous monitoring of multiple patients from the nurses' station.The Central View function offers all these advantages:

Vital signs monitor Tranquility II
This device allows you to monitor: EKG (3 or 5-lead), Heart Rate NIBP, Temperature, SpO2 (Digital or Masimo) and Respiration.
Furthermore, the Tranquility II can also function as a standalone monitor, providing limitless monitoring capabilities.

Effective solutions for vital signs monitoring

Having reliable vital signs monitors improves outcomes and, consequently, patient satisfaction. Additionally, it reduces nurses' workload and the costs associated with emergency interventions and potential negligence claims if a patient passes away. Discover the effective vital signs monitoring solutions offered by SCHILLER.


[1] Bernd Saugel et al. Automated Continuous Noninvasive Ward Monitoring: Validation of Measurement Systems Is the Real Challenge. Anesthesiology. March 2020, Vol. 132, 407–410. DOI:

[2] Frederic Michard et al. Rethinking Patient Surveillance on Hospital Wards. Anesthesiology September 2021, Vol. 135, 531–540.

[3] Zhuo Sun et al. Postoperative Hypoxemia Is Common and Persistent: A Prospective Blinded Observational Study. Anesth Analg.2015 Sep;121(3):709-715. doi: 10.1213/ANE.0000000000000836

[4] Alparslan Turan et al. Incidence, Severity, and Detection of Blood Pressure Perturbations after Abdominal Surgery: A Prospective Blinded Observational Study. Anesthesiology. 2019 Apr;130(4):550-559. DOI: 10.1097/ALN.0000000000002626

[5] Daryl A Jones. Rapid-response teams. N Engl J Med. 2011 Jul 14;365(2):139-46. DOI: 10.1056/NEJMra0910926

[6] John P Abenstein, Bradly J Narr. An ounce of prevention may equate to a pound of cure: can early detection and intervention prevent adverse events? Anesthesiology. 2010 Feb;112(2):272-3. DOI: 10.1097/ALN.0b013e3181ca858d

[7] Daniel Sessler Preventing respiratory depression. Anesthesiology. 2015 Mar;122(3):484-5. DOI: 10.1097/ALN.0000000000000565

[8] Patrick G Lyons et al.Characteristics of Rapid Response Calls in the United States: An Analysis of the First 402,023 Adult Cases From the Get With the Guidelines Resuscitation-Medical Emergency Team Registry. Crit Care Med. 2019 Oct;47(10):1283-1289. DOI: 10.1097/CCM.0000000000003912

[9] The International Surgical Outcomes Study group. Global patient outcomes after elective surgery: Prospective cohort study in 27 low-, middle-, and high-income countries.Br J Anaesth. 2016 Oct 31;117(5):601-609. DOI: 10.1093/bja/aew316



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