Technological aided assessment of the acutely ill patient - The case of postoperative complications

Hypoxemia in trauma patients receiving two different oxygen strategies: a TRAUMOX2 substudy

BACKGROUND

The randomized controlled trial, TRAUMOX2, compared early restrictive vs. liberal oxygen strategies for trauma patients. The objective of this substudy was to quantify the occurrence and duration of hypoxemic episodes during the trial's eight-hour intervention.

METHODS

This observational substudy analyzed a subset of patients at two trial sites in Denmark. Continuous pulse oximetry recorded arterial oxygen saturation (SpO2) during the intervention. The primary outcome was the proportion of patients who had episodes of hypoxemia with SpO2 < 90% for at least five minutes. Additionally, the study assessed differences in the occurrence and duration of hypoxemia between the restrictive and liberal oxygen groups.

RESULTS

This substudy included 82 patients. After secondary exclusion, 60 patients (median age, 49 years [interquartile range 33-61] and 75% male) were analyzed. Three out of 60 patients (5%) had at least one episode of SpO2 < 90% for at least five minutes (95% confidence interval 1-14%); Two patients in the restrictive oxygen group and one in the liberal oxygen group. Two episodes occurred during initial resuscitation, and one episode occurred in the intensive care unit following a procedure related to thoracic injuries.

CONCLUSIONS

In this substudy of 60 patients from the TRAUMOX2 trial, hypoxemia (SpO2 < 90% for at least five minutes) was observed in 5% of patients, with no difference between the restrictive and liberal oxygen groups. These findings suggest that, among trauma patients not already requiring continuous monitoring, such episodes of hypoxemia are relatively rare early post-trauma.

Short-term postoperative outcomes for obese versus non-obese inflammatory bowel disease patients undergoing bowel resection: a propensity score matched analysis

PURPOSE

Up to 40% of patients with inflammatory bowel disease (IBD) are obese. Obesity is a well-known risk factor for increased perioperative morbidity, but this risk has never been quantified in IBD patients undergoing abdominal surgery using the United States National Inpatient Sample (NIS) database. This study aims to compare postoperative morbidity between obese and non-obese patients undergoing bowel resection for IBD using recent NIS data.

METHODS

Adult patients who underwent bowel resection for IBD from 2015 to 2019 were identified in the NIS using ICD-10-CM coding. Patients were stratified into obese (BMI > 30 kg/m2) and non-obese groups, then propensity score matched (PSM) for demographic, operative, and hospital characteristics. The primary outcome was postoperative in-hospital morbidity. Secondary outcomes included postoperative in-hospital mortality, system-specific postoperative complications, total admission healthcare costs, and length of stay (LOS). Univariable and multivariable regressions were utilized.

RESULTS

Overall, 6601 non-obese patients and 671 obese patients were identified. The PSM cohort included 659 patients per group. Obese patients had significantly increased odds of experiencing postoperative in-hospital morbidity (aOR 1.50, 95% CI 1.10-2.03, p = 0.010) compared to non-obese patients. Specifically, obese patients experienced increased gastrointestinal complications (aOR 1.49, 95% CI 1.00-2.24, p = 0.050), and genitourinary complications (aOR 1.71, 95% CI 1.12-2.61, p = 0.013). There were no differences in total admission healthcare costs (MD - $2256.32, 95% CI - 19,144.54-14,631.9, p = 0.79) or LOS (MD 0.16 days, 95% CI - 0.93-1.27, p = 0.77).

CONCLUSIONS

Obese IBD patients are at greater risk of postoperative in-hospital morbidity than non-obese IBD patients. This supports targeted preoperative weight loss protocols for IBD patients to optimize surgical outcomes.

Clinical impact of vital sign abnormalities in patients admitted with acute exacerbation of chronic obstructive pulmonary disease: an observational study using continuous wireless monitoring

Early detection of abnormal vital signs is critical for timely management of acute hospitalised patients and continuous monitoring may improve this. We aimed to assess the association between preceding vital sign abnormalities and serious adverse events (SAE) in patients hospitalised with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Two hundred patients' vital signs were wirelessly and continuously monitored with peripheral oxygen saturation, heart rate, and respiratory rate during the first 4 days after admission for AECOPD. Non-invasive blood pressure was also measured every 30-60 min. The primary outcome was occurrence of SAE according to international definitions within 30 days and physiological data were analysed for preceding vital sign abnormalities. Data were presented as the mean cumulative duration of vital sign abnormalities per 24 h and analysed using Wilcoxon rank sum test. SAE during ongoing continuous monitoring occurred in 50 patients (25%). Patients suffering SAE during the monitoring period had on average 455 min (SD 413) per 24 h of any preceding vital sign abnormality versus 292 min (SD 246) in patients without SAE, p = 0.08, mean difference 163 min [95% CI 61-265]. Mean duration of bradypnea (respiratory rate < 11 min^-1) was 48 min (SD 173) compared with 30 min (SD 84) in patients without SAE, p = 0.01. In conclusion, the duration of physiological abnormalities was substantial in patients with AECOPD. There were no statistically significant differences between patients with and without SAE in the overall duration of preceding physiological abnormalities.Study registration: http://ClinicalTrials.gov (NCT03660501). Date of registration: Sept 6 2018.

Continuously monitored vital signs for detection of myocardial injury in high-risk patients - An observational study

Background

Patients are at risk of myocardial injury after major non‐cardiac surgery and during acute illness. Myocardial injury is associated with mortality, but often asymptomatic and currently detected through intermittent cardiac biomarker screening. This delays diagnosis, where vital signs deviations may serve as a proxy for early signs of myocardial injury. This study aimed to assess the association between continuous monitored vital sign deviations and subsequent myocardial injury following major abdominal cancer surgery and during acute exacerbation of chronic obstructive pulmonary disease.

Methods

Patients undergoing major abdominal cancer surgery or admitted with acute exacerbation of chronic obstructive pulmonary disease had daily troponin measurements. Continuous wireless monitoring of several vital signs was performed for up to 96 h after admission or surgery. The primary exposure was cumulative duration of peripheral oxygen saturation (SpO₂) below 85% in the 24 h before the primary outcome of myocardial injury, defined as a new onset ischaemic troponin elevation assessed daily. If no myocardial injury occurred, the primary exposure was based on the first 24 h of measurement.

Results

A total of 662 patients were continuously monitored and 113 (17%) had a myocardial injury. Cumulative duration of SpO₂ < 85% was significantly associated with myocardial injury (mean difference 14.2 min [95% confidence interval −4.7 to 33.1 min]; p = .005). Durations of hypoxaemia (SpO₂ < 88% and SpO₂ < 80%), tachycardia (HR > 110 bpm and HR > 130 bpm) and tachypnoea (RR > 24 min⁻¹ and RR > 30 min⁻¹) were also significantly associated with myocardial injury (p < .04, for all).

Conclusion

Duration of severely low SpO₂ detected by continuous wireless monitoring is significantly associated with myocardial injury in high‐risk patients admitted to hospital wards. The effect of early detection and interventions should be assessed next.

Continuous peripheral perfusion index in patients admitted to hospital wards - An observational study

INTRODUCTION

Risk patients admitted to hospital wards may quickly develop haemodynamic deterioration and early recognition has high priority to allow preventive intervention. The peripheral perfusion index (PPI) may be an indicator of circulatory distress by assessing peripheral perfusion non-invasively from photoplethysmography. We aimed to describe the characteristics of PPI in hospitalized patients since this is not well-studied.

MATERIALS AND METHODS

Patients admitted due to either acute exacerbation of chronic obstructive pulmonary disease (AECOPD) or after major abdominal cancer surgery were included in this study. Patients were monitored continuously up to 96 hours with a pulse oximeter. Comparisons between median PPI each day, time of day and admission type were described with mean difference (MD) and were analysed using Wilcoxon rank sum test and related to morbidity and mortality.

RESULTS

PPI data from 291 patients were recorded for a total of 9279 hours. Median PPI fell from 1.4 (inter quartile range, IQR 0.9-2.3) on day 1 to 1.0 (IQR 0.6-1.6) on day 4. Significant differences occurred between PPI day vs evening (MD = 0.18, 95% CI 0.16-0.20, P = .028), day vs night (MD = 0.56, 95% CI 0.49-0.62, P < .0001) and evening vs night (MD = 0.38, 95% CI 0.33-0.42, P = .002). No significant difference in median PPI between AECOPD and surgical patients was found (MD = 0.15, 95% CI -0.08-0.38, P = .62).

CONCLUSION

Lower PPI during daytime vs evening and night-time were seen for both populations. The highest frequency of serious adverse events and mortality was seen among patients with low median PPI. The clinical impact of PPI monitoring needs further confirmation.

Physiological abnormalities in patients admitted with acute exacerbation of COPD: an observational study with continuous monitoring

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) may rapidly require intensive care treatment. Evaluation of vital signs is necessary to detect physiological abnormalities (micro events), but patients may deteriorate between measurements. We aimed to assess if continuous monitoring of vital signs in patients admitted with AECOPD detects micro events more often than routine ward rounds. In this observational pilot study (NCT03467815), 30 adult patients admitted with AECOPD were included. Patients were continuously monitored with peripheral oxygen saturation (SpO₂), heart rate, and respiratory rate during the first 4 days after admission. Hypoxaemic events were defined as decreased SpO₂ for at least 60 s. Non-invasive blood pressure was also measured every 15-60 min. Clinical ward staff measured vital signs as part of Early Warning Score (EWS). Data were analysed using Fisher's exact test or Wilcoxon rank sum test. Continuous monitoring detected episodes of SpO₂ < 92% in 97% versus 43% detected by conventional EWS (p < 0.0001). Events of SpO₂ < 88% was detected in 90% with continuous monitoring compared with 13% with EWS (p < 0.0001). Sixty-three percent of patients had episodes of SpO₂ < 80% recorded by continuous monitoring and 17% had events lasting longer than 10 min. No events of SpO₂ < 80% was detected by EWS. Micro events of tachycardia, tachypnoea, and bradypnoea were also more frequently detected by continuous monitoring (p < 0.02 for all). Moderate and severe episodes of desaturation and other cardiopulmonary micro events during hospitalization for AECOPD are common and most often not detected by EWS.

Continuous vital sign monitoring after major abdominal surgery-Quantification of micro events

INTRODUCTION

Millions of patients undergo major abdominal surgery worldwide each year, and the post-operative phase carries a high risk of respiratory and circulatory complications. Standard ward observation of patients includes vital sign registration at regular intervals. Patients may deteriorate between measurements, and this may be detected by continuous monitoring. The aim of this study was to compare the number of micro events detected by continuous monitoring to those documented by the widely used standardized Early Warning Score (EWS).

METHODS

Fifty patients were continuously monitored with peripheral arterial oxygen saturation (SpO₂ ), heart rate (HR), and respiratory rate (RR) the first 4 days after major abdominal cancer surgery. EWS was monitored as routine practice. Number and duration of events were analyzed using Fisher's exact test and Wilcoxon rank sum test.

RESULTS

Continuous monitoring detected a SpO₂ <92% in 98% of patients vs 16% of patients detected by EWS (P < .0001). Micro events of SpO₂ <92% lasting longer than 60 minutes were found in 58% of patients by continuous monitoring vs 16% by the EWS (P < .0001). Fifty-two percent of patients had micro events of SpO₂ <85% lasting longer than 10 minutes. Continuous monitoring found tachycardia in 60% of patients vs 6% by the EWS. Frequency of events for bradycardia, tachypnea, and bradypnea showed similar patterns.

CONCLUSION

Very low SpO₂ and tachycardia in post-operative patients are common and under-diagnosed by the EWS. Continuous monitoring can discover these micro events and potentially contribute to earlier detection and, potentially, result in prevention of clinical complications.

Towards an automated multimodal clinical decision support system at the post anesthesia care unit

BACKGROUND

The aim of this study was to develop a predictive algorithm detecting early signs of deterioration (ESODs) in the post anesthesia care unit (PACU), thus being able to intervene earlier in the future to avoid serious adverse events. The algorithm must utilize continuously collected cardiopulmonary vital signs and may serve as an alternative to current practice, in which an alarm is activated by single parameters.

METHODS

The study was a single center, prospective cohort study including 178 patients admitted to the PACU after major surgical procedures. Peripheral blood oxygenation, arterial blood pressure, perfusion index, heart rate and respiratory rate were monitored continuously. Potential ESODs were automatically detected and scored by two independent experts with regards to the severity of the observation. Based on features extracted from the obtained measurements, a random forest classifier was trained, classifying each event being either an ESOD or not an ESOD. The algorithm was evaluated and compared to the automated single modality alarm system at the PACU.

RESULTS

The algorithm detected ESODs with an accuracy of 92.2% (99% CI: 89.6%-94.8%), sensitivity of 90.6% (99% CI: 85.7%-95.5%), specificity of 93.0% (99% CI: 89.9%-96.2%) and area under the receiver operating characteristic curve of 96.9% (99% CI: 95.3%-98.5%). The number of false alarms decreased by 85% (99% CI: 77%-93%) and the number of missed ESODs decreased by 73% (99% CI: 61%-85%) as compared to the currently used alarm system in the hospital. The algorithm was able to detect an ESOD in average 26.4 (99% CI: 1.1-51.7) minutes before the current single parameter system used in the PACU.

CONCLUSION

In conclusion, the proposed biomedical classification algorithm, when compared to the currently used single parameter alarm system of the hospital, showed significantly increased performance in both detecting ESODs fast and classifying these correctly. The clinical effect of the predictive system must be evaluated in future trials.

Review: Continuous Monitoring to Detect Failure to Rescue in Adult Postoperative Inpatients

Failure to rescue, or the unexpected death of a patient due to a preventable complication, is a nationally documented problem with numerous and multifaceted contributing factors. These factors include the frequency and method of collecting vital sign data, response to abnormal vital signs, and delays in the escalation of care for general ward patients who are showing signs of clinical deterioration. Patients' clinical deterioration can be complicated by concurrent secondary factors, including opioid abuse/dependence, being uninsured, or having sleep-disordered breathing. Using the Johns Hopkins Nursing Evidence-Based Practice Model, this integrative review synthesizes 43 research and nonresearch sources of evidence. Published between 2001 and 2017, these sources of evidence focus on failure to rescue, the multifaceted contributing factors to failure to rescue, and how continuous vital sign monitoring could ameliorate failure to rescue and its causes. Recommendations from the sources of evidence have been divided into system, structural, or technological categories.