Patterns of unexpected in-hospital deaths: a root cause analysis

Modified R-GLIM Score Is a Good Prognostic Tool to Predict a Long-Term Prognosis in Poor Conditioned Elderly Patients with Aspiration Pneumonia, a Pilot Study

BACKGROUND

While prognostic guidelines for pneumonia have widely allowed clinicians to treat patients, poor prognostic factors for 1- or 2-year survival times have never been mentioned to our knowledge.

PATIENTS AND METHODS

We conducted this retrospective study to evaluate whether malnutrition according to the GLIM criteria is a poor prognostic factor for 1- or 2-year survival among patients with aspiration pneumonia. All patients with community-onset aspiration pneumonia who were admitted to Aichi Medical University and had intervention from our nutrition support team (NST) in 2019 and 2020 were enrolled in this study.

RESULTS

A total of 56 patients were enrolled in the study. The mean age was 86 ± 6.5 and 25 (45%) were male. Thirty-one patients died during this observational period. Comparing the survival and death group, higher respiratory rate (RR) and malnutrition were seen more frequently in the death group than in the survival group. Then, the patients were divided into the following three groups: those with an RR ≥ 22 and malnutrition, those with malnutrition, and a control group [patients who were not malnourished and had a low RR (<22)]. Comparing the three groups, patients with an RR ≥ 22 and malnutrition had significantly shorter overall survival times (OSs) than those in the other groups (p = 0.009 by Log-Rank test) for 1-year prognosis. The result of 2-year prognosis displayed a statistical significance that was the same as that for 1-year prognosis (p = 0.004 by Log-Rank test). The Cox hazard regression model showed that a higher RR was an independent poor prognostic factor for 1- and 2-year survival among aspiration pneumonia patients.

CONCLUSIONS

This pilot study showed that combined scores of higher RR and malnutrition according to the GLIM criteria (modified R-GLIM score) was an independent poor prognostic factor for 1 or 2-year survival among super-elderly patients (aged over 80 years) with aspiration pneumonia.

Obstructive Sleep Apnea and Risk of Postoperative Complications after Non-Cardiac Surgery

Obstructive sleep apnea (OSA), a common sleep disorder, poses significant challenges in perioperative management due to its complexity and multifactorial nature. With a global prevalence of approximately 22.6%, OSA often remains undiagnosed, and increases the risk of cardiac and respiratory postoperative complications. Preoperative screening has become essential in many institutions to identify patients at increased risk, and experts recommend proceeding with surgery in the absence of severe symptoms, albeit with heightened postoperative monitoring. Anesthetic and sedative agents exacerbate upper airway collapsibility and depress central respiratory activity, complicating intraoperative management, especially with neuromuscular blockade use. Additionally, OSA patients are particularly prone to opioid-induced respiratory depression, given their increased sensitivity to opioids and heightened pain perception. Thus, regional anesthesia and multimodal analgesia are strongly advocated to reduce perioperative complication risks. Postoperative care for OSA patients necessitates vigilant monitoring and tailored management strategies, such as supplemental oxygen and Positive Airway Pressure therapy, to minimize cardiorespiratory complications. Health care institutions are increasingly focusing on enhanced monitoring and resource allocation for patient safety. However, the rising prevalence of OSA, heterogeneity in disease severity, and lack of evidence for the efficacy of costly perioperative measures pose challenges. The development of effective screening and monitoring algorithms, alongside reliable risk predictors, is crucial for identifying OSA patients needing extended postoperative care. This review emphasizes a multidimensional approach in managing OSA patients throughout the perioperative period, aiming to optimize patient outcomes and minimize adverse outcomes.

Comparing the use of aggressive end-of life care among frail and non-frail patients with cancer using a claims-based frailty index

INTRODUCTION

Despite mounting consensus that end-of-life (EOL) care for patients with cancer should focus on improving quality of life, many patients continue to receive aggressive, disease-oriented treatment until death. Within this group, patients with increased frailty may be at higher risk of adverse treatment-related outcomes. We therefore examined the relationship between degree of frailty and receipt of aggressive EOL care among Medicare-insured patients with cancer in Ohio.

MATERIALS AND METHODS

From the Ohio Cancer Incidence Surveillance System (OCISS) linked with Medicare claims, we identified patients diagnosed with breast, colorectal, lung, or prostate cancer who died between 2012 and 2016. Frailty was operationalized using a validated claims-based frailty index. Six quality indicators reflecting receipt of aggressive EOL care were identified from claims: (1) any cancer-directed treatment, (2) >1 emergency department (ED) visit, (3) >1 hospital admission, (4) any intensive care unit (ICU) admission in the last 30 days of life, (5) entry to hospice in the last three days of life, and (6) in-hospital mortality. Multivariable logistic regression analysis was performed to control for demographic factors, Medicare and Medicaid dual enrollment, and cancer type and stage in the relationship between frailty and aggressive EOL care.

RESULTS

Overall, 31,465 patients met selection criteria. Patients with moderate/severe frailty were less likely than non-/pre-frail patients to receive any aggressive EOL care (adjusted odds ratio [aOR] 0.92 [95% confidence interval 0.86-0.99]). This group was also less likely to undergo cancer-directed treatment in their last 30 days or to enter hospice in their last three days. Increasing frailty was associated with lower odds of admission to the ICU in the last 30 days of life (mild frailty: aOR 0.88 [0.83-0.94]; moderate/severe frailty: aOR 0.85 [0.78-0.92]) or of dying in-hospital (mild frailty: 0.85 [0.79-0.91]; moderate/severe frailty: aOR 0.74 [0.67-0.82]), but higher odds of having >1 ED visit in the last 30 days of life (mild frailty: aOR 1.43 [1.32-1.53]; moderate/severe frailty: aOR 1.61 [1.47-1.77]).

DISCUSSION

These findings suggest the need for more explicit discussion of emergency care seeking for patients with cancer at the end of life.

The effectiveness of supplemental oxygen and high-flow nasal cannula therapy in patients with obstructive sleep apnea in different clinical settings: A systematic review and meta-analysis

STUDY OBJECTIVE

To evaluate the effectiveness of supplemental oxygen therapy and high-flow nasal cannula (HFNC) therapy in patients with obstructive sleep apnea (OSA) in different clinical settings to assess its application to surgical patients in the postoperative setting.

DESIGN

A systematic search was conducted on MEDLINE and other databases from 1946 to December 16th, 2021. Title and abstract screening were conducted independently, and the lead investigators resolved conflicts. Meta-analyses were performed using a random-effects model and are presented as mean difference and standardized mean difference with 95% confidence intervals. These were calculated using RevMan 5.4.

PATIENTS

1395 and 228 OSA patients underwent oxygen therapy and HFNC therapy respectively.

INTERVENTIONS

Oxygen therapy and HFNC therapy.

MEASUREMENTS

Apnea-hypopnea index (AHI), oxyhemoglobin saturation (SpO₂), cumulative time with SPO₂ < 90% (CT90).

MAIN RESULTS

Twenty-seven oxygen therapy studies were included in the review, with ten randomized controlled trials (RCT), seven randomized crossovers, seven non-randomized crossovers, and three prospective cohorts. Pooled analyses showed that oxygen therapy significantly reduced AHI by 31% and increased SpO₂ by 5% versus baseline, and CPAP significantly reduced AHI by 84%, and increased SpO₂ by 3% versus baseline. CPAP was 53% more effective in reducing AHI than oxygen therapy, but both treatments had similar effectiveness in increasing SpO₂. Nine HFNC studies were included in the review, with five prospective cohorts, three randomized crossovers, and one RCT. Pooled analyses showed that HFNC therapy significantly reduced AHI by 36% but did not substantially increase SpO₂.

CONCLUSIONS

Oxygen therapy effectively reduces AHI and increases SpO₂ in patients with OSA. CPAP is more effective in reducing AHI than oxygen therapy. HFNC therapy is effective in reducing AHI. Although both oxygen therapy and HFNC therapy effectively reduce AHI, more research is needed to draw conclusions on clinical outcomes.

Clinical validation of a wearable respiratory rate device: A brief report

BACKGROUND

Respiratory rate (RR) is used for the diagnosis and management of medical conditions and can predict clinical changes. Heavy workload, understaffing, and errors related to poor recording make it underutilized. Wearable devices may facilitate its use.

METHODS

RR measurements using a wearable photoplethysmography-based monitor were compared with medical grade devices in complementary clinical scenarios: Study one included a comparison to a capnograph in 35 healthy volunteers; Study two included a comparison to a ventilator monitor in 18 ventilated patients; and Study three included a comparison to capnograph in 92 COVID-19 patients with active pulmonary disease. Pearson's correlations and Bland-Altman analysis were used to assess the accuracy and agreement between the measurement techniques, including stratification for Body Mass Index (BMI) and skin tone. Statistical significance was set at p ≤ 0.05.

RESULTS

High correlation was found in all studies (r = 0.991, 0.884, and 0.888, respectively, p < 0.001 for all). 95% LOA of ±2.3, 1.7-(-1.6), and ±3.9 with a bias of < 0.1 breaths per minute was found in Bland-Altman analysis in studies 1,2, and 3, respectively. In all, high accordance was found in all sub-groups.

CONCLUSIONS

RR measurements using the wearable monitor were highly-correlated with medical-grade devices in various clinical settings.

TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT03603860.

Respiratory monitoring of nonintubated patients in nonoperating room settings: old and new technologies

PURPOSE OF REVIEW

Postoperative mortality in the 30 days after surgery remains disturbingly high. Inadequate, intermittent and incomplete monitoring of vital signs in the nonoperating room environment is common practice. The rise of nonoperating room anaesthesia and sedation outside the operating room has highlighted the need to develop new and robust methods of portable continuous respiratory monitoring. This review provides a summary of old and new technologies in this environment.

RECENT FINDINGS

Technical advances have made possible the utilization of established monitoring to extrapolate respiratory rate, the increased availability and user friendliness of side stream capnography and the advent of other innovative systems. The use of aggregate signals wherein different modalities compensate for individual shortcomings seem to provide a reliable and artefact-free system.

SUMMARY

Respiratory monitoring is required in several situations and patient categories outside the operating room. The chosen modality must be able to detect respiratory compromise in a timely and accurate manner. Combing several modalities in a nonobtrusive, nontethered system and having an integrated output seems to give a reliable and responsive signal.

Clinical implications of opioid-induced ventilatory impairment

Opioid-induced ventilatory impairment is the primary mechanism of harm from opioid use. Opioids suppress the activity of the central respiratory centres and are sedating, leading to impairment of alveolar ventilation.Respiratory physiological changes induced with acute opioid use include depression of the hypercapnic ventilatory response and hypoxic ventilatory response. In chronic opioid use a compensatory increase in hypoxic ventilatory response maintains ventilation and contributes to the onset of sleep-disordered breathing patterns of central sleep apnoea and ataxic breathing. Supplemental oxygen use in those at risk of opioid-induced ventilatory impairment requires careful consideration by the clinician to prevent failure to detect hypoventilation, if oximetry is being relied on, and the overriding of hypoxic ventilatory drive. Obstructive sleep apnoea and opioid-induced ventilatory impairment are frequently associated, with this interrelationship being complex and often unpredictable. Monitoring the patient for opioid-induced ventilatory impairment poses challenges in the areas of reliability, avoidance of alarm fatigue, cost, and personnel demands. Many situations remain in which patients cannot be provided effective analgesia without opioids, and for these the clinician requires a comprehensive knowledge of opioid-induced ventilatory impairment.

Opioids in acute pain: Towards getting the right balance

Misuse of prescription opioids forced an inevitable response from authorities to intervene with consequences felt by all.In the Australian community one person will die for approximately every 3600 adults prescribed opioids, while in the hospital setting a postoperative patient managed primarily with opioids, as opposed to epidural analgesia, has an additional risk of death as high as between one in 56 to 477.Opioids maintain a valid role in acute pain management when use is reasoned and with full awareness of the harms and how they are to be avoided, such as in those at risk of ongoing use, the opioid naïve, and when opioid-induced ventilatory impairment may occur.Clinicians managing acute pain can focus on assessing pain versus nociception, strategically apply antinociceptive medications and neural blockade when indicated, assess pain with an emphasis on the degree of bothersomeness and functional impairment and, finally, optimise the use of framing and placebo-enhancing communication to minimise reliance on medications.

Respiration monitoring in PACU using ventilation and gas exchange parameters

The importance of perioperative respiration monitoring is highlighted by high incidences of postoperative respiratory complications unrelated to the original disease. The objectives of this pilot study were to (1) simultaneously acquire respiration rate (RR), tidal volume (TV), minute ventilation (MV), SpO₂ and PetCO₂ from patients in post-anesthesia care unit (PACU) and (2) identify a practical continuous respiration monitoring method by analyzing the acquired data in terms of their ability and reliability in assessing a patient’s respiratory status. Thirteen non-intubated patients completed this observational study. A portable electrical impedance tomography (EIT) device was used to acquire RR_EIT, TV and MV, while PetCO₂, RR_Cap and SpO₂ were measured by a Capnostream35. Hypoventilation and respiratory events, e.g., apnea and hypopnea, could be detected reliably using RR_EIT, TV and MV. PetCO₂ and SpO₂ provided the gas exchange information, but were unable to detect hypoventilation in a timely fashion. Although SpO₂ was stable, the sidestream capnography using the oronasal cannula was often unstable and produced fluctuating PetCO₂ values. The coefficient of determination (R²) value between RR_EIT and RR_Cap was 0.65 with a percentage error of 52.5%. Based on our results, we identified RR, TV, MV and SpO₂ as a set of respiratory parameters for robust continuous respiration monitoring of non-intubated patients. Such a respiration monitor with both ventilation and gas exchange parameters would be reliable and could be useful not only for respiration monitoring, but in making PACU discharge decisions and adjusting opioid dosage on general hospital floor. Future studies are needed to evaluate the potential clinical utility of such an integrated respiration monitor.

Clinical Sign-Based Rapid Response Team Call Criteria for Identifying Patients Requiring Intensive Care Management in Japan

Background and Objectives: For effective function of the rapid response system (RRS), prompt identification of patients at a high risk of cardiac arrest and RRS activation without hesitation are important. This study aimed to identify clinical factors that increase the risk of intensive care unit (ICU) transfer and cardiac arrest to identify patients who are likely to develop serious conditions requiring ICU management and appropriate RRS activation in Japan. Materials and Methods: We performed a single-center, case control study among patients requiring a rapid response team (RRT) call from 2017 to 2020. We extracted the demographic data, vital parameters, blood oxygen saturation (SpO₂) and the fraction of inspired oxygen (FiO₂) from the medical records at the time of RRT call. The patients were divided into two groups to identify clinical signs that correlated with the progression of clinical deterioration. Patient characteristics in the two groups were compared using statistical tests based on the distribution. Receiver operating characteristic (ROC) curve analysis was used to identify the appropriate cut-off values of vital parameters or FiO₂ that showed a significant difference between-group. Multivariate logistic regression analysis was used to identify patient factors that were predictive of RRS necessity. Results: We analyzed the data of 65 patients who met our hospital’s RRT call criteria. Among the clinical signs in RRT call criteria, respiratory rate (RR) (p < 0.01) and the needed FiO₂ were significantly increased (p < 0.01) in patients with severe disease course. ROC curve analysis revealed RR and needed FiO₂ cut-off values of 25.5 breaths/min and 30%. The odds ratio for the progression of clinical deterioration was 40.5 times higher with the combination of RR ≥ 26 breaths/min and needed FiO₂ ≥ 30%. Conclusions: The combined use of RR ≥ 26 breaths/min and needed FiO₂ ≥ 30% might be valid for identifying patients requiring intensive care management.

The effect of an eye mask on midazolam requirement for sedation during spinal anesthesia: a randomized controlled trial

Background

Midazolam is frequently used for sedation during spinal anesthesia. However, external environmental factors, such as bright surgical lights, may hamper patient relaxation, which may lead to an increase in the dose of midazolam required and the likelihood of adverse drug effects. We investigated whether using an eye mask to block the external environment could reduce midazolam requirements during spinal anesthesia.

Methods

Participants aged 18–‒80 years, scheduled for elective surgery under spinal anesthesia, were randomly divided into a masked group (wearing eye masks during surgery, n = 20) and a control group (no mask, n = 18). The sedation level was assessed using a modified Observer Assessment of Alertness and Sedation (MOAA/S) scale. Midazolam (1 mg) was incrementally administered every 5 min until moderate sedation (MOAA/S score of 3) was achieved. The bispectral index (BIS) was monitored, and the onset and maintenance times of a BIS < 80 were recorded.

Results

The two groups had similar demographic characteristics. The midazolam requirements were significantly lower in the masked group than in the control group (2.8 mg vs. 3.7 mg, P = 0.024). However, the onset and maintenance times for a BIS < 80 were similar. In addition, there were no significant differences in the incidence of side effects or patient satisfaction between the two groups.

Conclusions

Blocking the external environment with an eye mask during spinal anesthesia can reduce the requirement for sedatives, such as midazolam.

Trial registration

The trial was retrospectively registered with the Clinical Research Information Service (No. KCT0005528, 15/10/2020) entitled “Can we reduce an amount of sleeping pills just by blocking light?”.

Ventilation Monitoring

Ventilation or breathing is vital for life yet is not well monitored in hospital or at home. Respiratory rate is a neglected vital sign and tidal volumes together with breath sounds are checked infrequently in many patients. Medications with the potential to depress ventilation are frequently administered, and may be accentuated by obesity causing airway obstruction in the form of sleep apnea. Sepsis may adversely affect ventilation by causing an increase in respiratory rate, often a very early sign of infection. Changes in ventilation may be early signs of deterioration in the patient.

Evaluation of respiratory rate monitoring using a microwave Doppler sensor mounted on the ceiling of an intensive care unit: a prospective observational study

Continuous monitoring of the respiratory rate is crucial in an acute care setting. Contact respiratory monitoring modalities such as capnography and thoracic impedance pneumography are prone to artifacts, causing false alarms. Moreover, their cables can restrict patient behavior or interrupt patient care. A microwave Doppler sensor is a novel non-contact continuous respiratory rate monitor. We compared respiratory rate measurements performed with a microwave Doppler sensor mounted on the ceiling of an intensive care unit with those obtained by conventional methods in conscious and spontaneously breathing patients. Participants' respiratory rate was simultaneously measured by visual counting of chest wall movements for 60 s; a microwave Doppler sensor; capnography, using an oxygen mask; and thoracic impedance pneumography, using electrocardiogram electrodes. Bland-Altman analysis for repeated measures was performed to calculate bias and 95% limits of agreement between the respiratory rate measured by visual counting (reference) and that measured by each of the other methods. Among 52 participants, there were 336 (microwave Doppler sensor), 275 (capnography), and 336 (thoracic impedance pneumography) paired respiratory rate data points. Bias (95% limits of agreement) estimates were as follows: microwave Doppler sensor, 0.3 (- 6.1 to 6.8) breaths per minute (bpm); capnography, - 1.3 (- 8.6 to 6.0) bpm; and thoracic impedance pneumography, 0.1 (- 4.4 to 4.7) bpm. Compared to visual counting, the microwave Doppler sensor showed small bias; however, the limits of agreement were similar to those observed in other conventional methods. Our monitor and the conventional ones are not interchangeable with visual counting.Trial registration number: UMIN000032021, March/30/2018.

The effectiveness of continuous respiratory rate monitoring in predicting hypoxic and pyrexic events: a retrospective cohort study

Respiratory rate (RR) is routinely used to monitor patients with infectious, cardiac and respiratory diseases and is a component of early warning scores used to predict patient deterioration. However, it is often measured visually with considerable bias and inaccuracy.Objectives. Firstly, to compare distribution and accuracy of electronically measured RR (EMRR) and visually measured RR (VMRR). Secondly, to determine whether, and how far in advance, continuous electronic RR monitoring can predict oncoming hypoxic and pyrexic episodes in infectious respiratory disease.Approach.A retrospective cohort study analysing the difference between EMRR and VMRR was conducted using patient data from a large tertiary hospital. Cox proportional hazards models were used to determine whether continuous, EMRR measurements could predict oncoming hypoxic (SpO₂ < 92%) and pyrexic (temperature >38 °C) episodes.Main results.Data were gathered from 34 COVID-19 patients, from which a total of 3445 observations of VMRR (independent of Hawthorne effect), peripheral oxygen saturation and temperature and 729 117 observations of EMRR were collected. VMRR had peaks in distribution at 18 and 20 breaths per minute. 70.9% of patients would have had a change of treatment during their admission based on the UK's National Early Warning System if EMRR was used in place of VMRR. An elevated EMRR was predictive of hypoxic (hazard ratio: 1.8 (1.05-3.07)) and pyrexic (hazard ratio: 9.7 (3.8-25)) episodes over the following 12 h.Significance.Continuous EMRR values are systematically different to VMRR values, and results suggest it is a better indicator of true RR as it has lower kurtosis, higher variance, a lack of peaks at expected values (18 and 20) and it measures a physiological component of breathing directly (abdominal movement). Results suggest EMRR is a strong marker of oncoming hypoxia and is highly predictive of oncoming pyrexic events in the following 12 h. In many diseases, this could provide an early window to escalate care prior to deterioration, potentially preventing morbidity and mortality.

Perioperative Management of the Patient With Obstructive Sleep Apnea: A Narrative Review

The prevalence of obstructive sleep apnea (OSA) has reached 1 billion people worldwide, implying significant risk for the perioperative setting as patients are vulnerable to cardiopulmonary complications, critical care requirement, and unexpected death. This review summarizes main aspects and considerations for the perioperative management of OSA, a condition of public health concern. Critical determinants of perioperative risk include OSA-related changes in upper airway anatomy with augmented collapsibility, diminished capability of upper airway dilator muscles to respond to airway obstruction, disparities in hypoxemia and hypercarbia arousal thresholds, and instability of ventilatory control. Preoperative OSA screening to identify patients at increased risk has therefore been implemented in many institutions. Experts recommend that in the absence of severe symptoms or additional compounding health risks, patients may nevertheless proceed to surgery, while heightened awareness and the adjustment of postoperative care is required. Perioperative caregivers should anticipate difficult airway management in OSA and be prepared for airway complications. Anesthetic and sedative drug agents worsen upper airway collapsibility and depress central respiratory activity, while the risk for postoperative respiratory compromise is further increased with the utilization of neuromuscular blockade. Consistently, opioid analgesia has proven to be complex in OSA, as patients are particularly prone to opioid-induced respiratory depression. Moreover, basic features of OSA, including intermittent hypoxemia and repetitive sleep fragmentation, gradually precipitate a higher sensitivity to opioid analgesic potency along with an increased perception of pain. Hence, regional anesthesia by blockade of neural pathways directly at the site of surgical trauma as well as multimodal analgesia by facilitating additive and synergistic analgesic effects are both strongly supported in the literature as interventions that may reduce perioperative complication risk. Health care institutions are increasingly allocating resources, including those of postoperative enhanced monitoring, in an effort to increase patient safety. The implementation of evidence-based perioperative management strategies is however burdened by the rising prevalence of OSA, the large heterogeneity in disease severity, and the lack of evidence on the efficacy of costly perioperative measures. Screening and monitoring algorithms, as well as reliable risk predictors, are urgently needed to identify OSA patients that are truly in need of extended postoperative surveillance and care. The perioperative community is therefore challenged to develop feasible pathways and measures that can confer increased patient safety and prevent complications in patients with OSA.

Perioperative adherence to continuous positive airway pressure and its effect on postoperative nocturnal hypoxemia in obstructive sleep apnea patients: a prospective cohort study

Background

Although continuous positive airway pressure (CPAP) is the first line treatment for obstructive sleep apnea (OSA) patients, the perioperative adherence rate is unclear. The objective of this study was to determine the perioperative adherence rate of patients with OSA with a CPAP prescription and the effect of adherence on nocturnal oxygen saturation.

Methods

This prospective cohort study included adult surgical patients with a diagnosis of OSA with CPAP prescription undergoing elective non-cardiac surgery. Patients were divided into CPAP adherent and non-adherent groups based on duration of usage (≥ 4 h/night). Overnight oximetry was performed preoperatively and on postoperative night 1 and 2 (N1, N2). The primary outcome was adherence rate and the secondary outcome was nocturnal oxygen saturation.

Results

One hundred and thirty-two patients completed the study. CPAP adherence was 61% preoperatively, 58% on postoperative N1, and 59% on N2. Forty-nine percent were consistently CPAP adherent pre- and postoperatively. Using a linear fixed effects regression, oxygen desaturation index (ODI) was significantly improved by CPAP adherence (p = 0.0011). The interaction term CPAP x N1 was significant (p = 0.0015), suggesting that the effect of CPAP adherence varied on N1 vs preoperatively. There was no benefit of CPAP adherence on postoperative mean SpO₂, minimum SpO₂, and percentage of sleep duration with SpO₂ < 90%. Use of supplemental oxygen therapy was much lower in the CPAP adherent group vs non-adherent group (9.8% vs 46.5%, p <  0.001).

Conclusions

Among patients with a preoperative CPAP prescription, approximately 50% were consistently adherent. CPAP adherence was associated with improved preoperative ODI and the benefit was maintained on N1. These modest effects may be underestimated by a higher severity of OSA in the CPAP adherent group and a higher rate of oxygen supplementation in the non-adherent group.

Trial registration

ClinicalTrials.Gov registry (NCT02796846).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01371-0.

Integrated pulmonary index can predict respiratory compromise in high-risk patients in the post-anesthesia care unit: a prospective, observational study

Background

Respiratory compromise (RC) including hypoxia and hypoventilation is likely to be missed in the postoperative period. Integrated pulmonary index (IPI) is a comprehensive respiratory parameter evaluating ventilation and oxygenation. It is calculated from four parameters: end-tidal carbon dioxide, respiratory rate, oxygen saturation measured by pulse oximetry (SpO₂), and pulse rate. We hypothesized that IPI monitoring can help predict the occurrence of RC in patients at high-risk of hypoventilation in post-anesthesia care units (PACUs).

Methods

This prospective observational study was conducted in two centers and included older adults (≥ 75-year-old) or obese (body mass index ≥ 28) patients who were at high-risk of hypoventilation. Monitoring was started on admission to the PACU after elective surgery under general anesthesia. We investigated the onset of RC defined as respiratory events with prolonged stay in the PACU or transfer to the intensive care units; airway narrowing, hypoxemia, hypercapnia, wheezing, apnea, and any other events that were judged to require interventions. We evaluated the relationship between several initial parameters in the PACU and the occurrence of RC. Additionally, we analyzed the relationship between IPI fluctuation during PACU stay and the occurrences of RC using individual standard deviations of the IPI every five minutes (IPI-SDs).

Results

In total, 288 patients were included (199 elderly, 66 obese, and 23 elderly and obese). Among them, 18 patients (6.3 %) developed RC. The initial IPI and SpO₂ values in the PACU in the RC group were significantly lower than those in the non-RC group (6.7 ± 2.5 vs. 9.0 ± 1.3, p < 0.001 and 95.9 ± 4.2 % vs. 98.3 ± 1.9 %, p = 0.040, respectively). We used the area under the receiver operating characteristic curves (AUC) to evaluate their ability to predict RC. The AUCs of the IPI and SpO₂ were 0.80 (0.69–0.91) and 0.64 (0.48–0.80), respectively. The IPI-SD, evaluating fluctuation, was significantly greater in the RC group than in the non-RC group (1.47 ± 0.74 vs. 0.93 ± 0.74, p = 0.002).

Conclusions

Our study showed that low value of the initial IPI and the fluctuating IPI after admission to the PACU predict the occurrence of RC. The IPI might be useful for respiratory monitoring in PACUs and ICUs after general anesthesia.

Continuous non-contact respiratory rate and tidal volume monitoring using a Depth Sensing Camera

The monitoring of respiratory parameters is important across many areas of care within the hospital. Here we report on the performance of a depth-sensing camera system for the continuous non-contact monitoring of Respiratory Rate (RR) and Tidal Volume (TV), where these parameters were compared to a ventilator reference. Depth sensing data streams were acquired and processed over a series of runs on a single volunteer comprising a range of respiratory rates and tidal volumes to generate depth-based respiratory rate (RR_depth) and tidal volume (TV_depth) estimates. The bias and root mean squared difference (RMSD) accuracy between RR_depth and the ventilator reference, RR_vent, across the whole data set was found to be -0.02 breaths/min and 0.51 breaths/min respectively. The least squares fit regression equation was determined to be: RR_depth = 0.96 × RR_vent + 0.57 breaths/min and the resulting Pearson correlation coefficient, R, was 0.98 (p < 0.001). Correspondingly, the bias and root mean squared difference (RMSD) accuracy between TV_depth and the reference TV_vent across the whole data set was found to be - 0.21 L and 0.23 L respectively. The least squares fit regression equation was determined to be: TV_depth = 0.79 × TV_vent-0.01 L and the resulting Pearson correlation coefficient, R, was 0.92 (p < 0.001). In conclusion, a high degree of agreement was found between the depth-based respiration rate and its ventilator reference, indicating that RR_depth is a promising modality for the accurate non-contact respiratory rate monitoring in the clinical setting. In addition, a high degree of correlation between depth-based tidal volume and its ventilator reference was found, indicating that TV_depth may provide a useful monitor of tidal volume trending in practice. Future work should aim to further test these parameters in the clinical setting.

Noncontact Respiratory Monitoring Using Depth Sensing Cameras: A Review of Current Literature

There is considerable interest in the noncontact monitoring of patients as it allows for reduced restriction of patients, the avoidance of single-use consumables and less patient-clinician contact and hence the reduction of the spread of disease. A technology that has come to the fore for noncontact respiratory monitoring is that based on depth sensing camera systems. This has great potential for the monitoring of a range of respiratory information including the provision of a respiratory waveform, the calculation of respiratory rate and tidal volume (and hence minute volume). Respiratory patterns and apneas can also be observed in the signal. Here we review the ability of this method to provide accurate and clinically useful respiratory information.

The Importance of Respiratory Rate Monitoring: From Healthcare to Sport and Exercise

Respiratory rate is a fundamental vital sign that is sensitive to different pathological conditions (e.g., adverse cardiac events, pneumonia, and clinical deterioration) and stressors, including emotional stress, cognitive load, heat, cold, physical effort, and exercise-induced fatigue. The sensitivity of respiratory rate to these conditions is superior compared to that of most of the other vital signs, and the abundance of suitable technological solutions measuring respiratory rate has important implications for healthcare, occupational settings, and sport. However, respiratory rate is still too often not routinely monitored in these fields of use. This review presents a multidisciplinary approach to respiratory monitoring, with the aim to improve the development and efficacy of respiratory monitoring services. We have identified thirteen monitoring goals where the use of the respiratory rate is invaluable, and for each of them we have described suitable sensors and techniques to monitor respiratory rate in specific measurement scenarios. We have also provided a physiological rationale corroborating the importance of respiratory rate monitoring and an original multidisciplinary framework for the development of respiratory monitoring services. This review is expected to advance the field of respiratory monitoring and favor synergies between different disciplines to accomplish this goal.

A Phase I Placebo-Controlled Trial Comparing the Effects of Buprenorphine Buccal Film and Oral Oxycodone Hydrochloride Administration on Respiratory Drive

Introduction

Buprenorphine is a partial μ-opioid receptor agonist that, unlike full μ-opioid receptor agonists, has been shown to have a ceiling effect on respiratory depression. Buprenorphine buccal film (BBF) is approved by the US Food and Drug Administration for use in patients with chronic pain severe enough to require daily, around-the-clock, long-term opioid treatment and for whom alternative treatment options are inadequate. This study was conducted to compare the effects of BBF and immediate-release oral oxycodone hydrochloride administration on respiratory drive, as measured by the ventilatory response to hypercapnia (VRH) after drug administration.

Methods

Subjects (N = 19) were men and women, ages 27–41 years, self-identifying as recreational opioid users who were not physically dependent on opioids as determined via a Naloxone Challenge Test. Respiratory drive was evaluated by measuring VRH through the assessment of the maximum decrease in minute ventilation (E_max) after administration of each treatment. The treatments utilized in this study included 300, 600, and 900 μg BBF; 30 and 60 mg orally administered oxycodone; and placebo (each separated by a 7-day washout period). Effects on respiratory drive were assessed using a double-blind, double-dummy, six-treatment, six-period, placebo-controlled, randomized crossover design. Statistical analyses were performed using a linear mixed-effects model.

Results

The least squares mean differences in minute volume E_max (L/min, versus placebo) were as follows: 300 μg BBF (+ 1.24, P = 0.529), 600 μg BBF (+ 0.23, P = 0.908), 900 μg BBF (+ 0.93, P = 0.637), 30 mg oxycodone (− 0.79, P = 0.687), and 60 mg oxycodone (− 5.23, P = 0.010).

Conclusions

BBF did not significantly reduce respiratory drive at any dose compared with placebo, including at the maximum available prescription dose of 900 μg. Administration of oxycodone resulted in a significant dose-dependent decrease in respiratory drive. These data suggest that BBF may be a safer treatment option than full μ-opioid receptor agonists for patients with chronic pain.

Trial Registration

ClinicalTrials.gov identifier, NCT03996694.

Electronic supplementary material

The online version of this article (10.1007/s12325-020-01481-0) contains supplementary material, which is available to authorized users.

Predictor of respiratory disturbances during gastric endoscopic submucosal dissection under deep sedation

BACKGROUND

Sedation is commonly performed for the endoscopic submucosal dissection (ESD) of early gastric cancer. Severe hypoxemia occasionally occurs due to the respiratory depression during sedation.

AIM

To establish predictive models for respiratory depression during sedation for ESD.

METHODS

Thirty-five adult patients undergoing sedation using propofol and pentazocine for gastric ESDs participated in this prospective observational study. Preoperatively, a portable sleep monitor and STOP questionnaires, which are the established screening tools for sleep apnea syndrome, were utilized. Respiration during sedation was assessed by a standard polysomnography technique including the pulse oximeter, nasal pressure sensor, nasal thermistor sensor, and chest and abdominal respiratory motion sensors. The apnea-hypopnea index (AHI) was obtained using a preoperative portable sleep monitor and polysomnography during ESD. A predictive model for the AHI during sedation was developed using either the preoperative AHI or STOP questionnaire score.

RESULTS

All ESDs were completed successfully and without complications. Seventeen patients (49%) had a preoperative AHI greater than 5/h. The intraoperative AHI was significantly greater than the preoperative AHI (12.8 ± 7.6 events/h vs 9.35 ± 11.0 events/h, P = 0.049). Among the potential predictive variables, age, body mass index, STOP questionnaire score, and preoperative AHI were significantly correlated with AHI during sedation. Multiple linear regression analysis determined either STOP questionnaire score or preoperative AHI as independent predictors for intraoperative AHI ≥ 30/h (area under the curve [AUC]: 0.707 and 0.833, respectively) and AHI between 15 and 30/h (AUC: 0.761 and 0.778, respectively).

CONCLUSION

The cost-effective STOP questionnaire shows performance for predicting abnormal breathing during sedation for ESD that was equivalent to that of preoperative portable sleep monitoring.

Evaluating the Incidence of Opioid-Induced Respiratory Depression Associated with Oliceridine and Morphine as Measured by the Frequency and Average Cumulative Duration of Dosing Interruption in Patients Treated for Acute Postoperative Pain

Background and Objective

Opioid-induced respiratory depression (OIRD) is a potentially fatal complication associated with conventional opioids. Currently, there is a paucity of validated endpoints available to measure respiratory safety. Oliceridine, an investigational intravenous (IV) opioid, is a G-protein selective μ-agonist with limited activity on β-arrestin2, a signaling pathway associated with adverse events including OIRD. In controlled phase III trials, oliceridine 0.35 mg and 0.5 mg demand doses demonstrated comparable analgesia to morphine 1 mg with favorable improvements in respiratory safety. In this exploratory analysis, we report dosing interruption (DI) and average cumulative duration of DI (CDDI) for both oliceridine and morphine.

Methods

Patients requiring analgesia after bunionectomy or abdominoplasty were randomized to IV demand doses of placebo, oliceridine (0.1 mg, 0.35 mg, or 0.5 mg), or morphine (1 mg), administered via patient-controlled analgesia (PCA), following a loading dose (oliceridine 1.5 mg, morphine 4 mg, volume-matched placebo) with a 6-min lockout interval. Certified nurse anesthetists monitored each patient and withheld study medication according to the patient’s respiratory status. For each patient, the duration of all DIs was summed and reported as CDDI. A zero-inflated gamma mixture model was used to compute the mean CDDI for each treatment.

Results

Proportion of patients with DI was lower with oliceridine (0.1 mg: 3.2%, 0.35 mg: 13.9%, 0.5 mg: 15.1%) versus morphine (22%). The CDDI was also lower across all demand doses of oliceridine versus morphine.

Conclusion

Using DI as a surrogate for OIRD indicates improved respiratory safety with oliceridine versus morphine that merits further investigation.

Electronic supplementary material

The online version of this article (10.1007/s40261-020-00936-0) contains supplementary material, which is available to authorized users.

Unanticipated Respiratory Compromise and Unplanned Intubations on General Medical and Surgical Floors

BACKGROUND

Unanticipated respiratory compromise that lead to unplanned intubations is a known phenomenon in hospitalized patients. Most events occur in patients at high risk in well-monitored units; less is known about the incidence, risk factors, and trajectory of patients thought at low risk on lightly monitored general care wards. The aims of our study were to quantify demographic and clinical characteristics associated with unplanned intubations on general care floors and to analyze the medications administered, monitoring strategies, and vital-sign trajectories before the event.

METHODS

We performed a multicenter retrospective cohort study of hospitalized subjects on the general floor who had unanticipated, unplanned intubations on general care floors from August 2014 to February 2018.

RESULTS

We identified 448 unplanned intubations. The incidence rate was 0.420 per 1,000 bed-days (95% CI 0.374-0.470) in the academic hospital and was 0.430 (95% CI 0.352-0.520) and 0.394 per 1,000 bed-days (95% CI 0.301-0.506) at our community hospitals. Extrapolating these rates to total hospital admissions in the United States, we estimate 64,000 events annually. The mortality rate was 49.1%. Within 12 h preceding the event, 35.3% of the subjects received opiates. All received vital-sign assessments. Most were monitored with pulse oximetry. In contrast, 2.5% were on cardiac telemetry, and only 4 subjects used capnography; 53.7% showed significant vital-sign changes in the 24 h before the event. However, 46.3% had no significant change in any vital signs.

CONCLUSIONS

Our study showed unanticipated respiratory compromise that required an unplanned intubation of subjects on the general care floor, although not common, carried a high mortality. Besides pulse oximetry and routine vital-sign assessments, very little monitoring was in use. A significant portion of the subjects had no vital-sign abnormalities leading up to the event. Further research is needed to determine the phenotype of the different etiologies of unexpected acute respiratory failure to identify better risk stratification and monitoring strategies.

Method of respiratory rate measurement using a unique wearable platform and an adaptive optical-based approach

Background

An efficient and accurate method of respiratory rate measurement is still missing in hospital general wards and triage. The goal of this study is to propose a method of respiratory rate measurement that has a potential to be used in general wards, triage, and different hospital settings with comparable performance. We propose a method of respiratory rate measurement that combines a unique wearable platform with an adaptive and optical approach. The optical approach is based on a direct-contact optical diffuse reflectance phenomenon. An adaptive algorithm is developed that computes the first respiratory rate and uses it to select a band. The band then chooses a set of unique optimized parameters in the algorithm to calculate and improve the respiratory rate. We developed a study to compare the proposed method against reference manual counts from 82 patients diagnosed with respiratory diseases.

Results

We found good agreement between the proposed method of respiratory rate measurement and reference manual counts. The performance of the proposed method highlighted deviations with a 95% confidence interval (C.I.) of − 3.34 and 3.67 breaths per minute (bpm) and a mean bias and standard deviation (STD) of 0.05 bpm and 2.56 bpm, respectively.

Conclusions

The performance of the proposed method of respiratory rate measurement is comparable with current manual counting and other respiratory rate devices reported. The method has additional advantages that include ease-of-use, quick setup time, and being mobile for wider clinical use. The proposed method has the potential as a tool to measure respiratory rates in a number of use cases.

Situation Awareness-Oriented Patient Monitoring with Visual Patient Technology: A Qualitative Review of the Primary Research

Visual Patient technology is a situation awareness-oriented visualization technology that translates numerical and waveform patient monitoring data into a new user-centered visual language. Vital sign values are converted into colors, shapes, and rhythmic movements-a language humans can easily perceive and interpret-on a patient avatar model in real time. In this review, we summarize the current state of the research on the Visual Patient, including the technology, its history, and its scientific context. We also provide a summary of our primary research and a brief overview of research work on similar user-centered visualizations in medicine. In several computer-based studies under various experimental conditions, Visual Patient transferred more information per unit time, increased perceived diagnostic certainty, and lowered perceived workload. Eye tracking showed the technology worked because of the way it synthesizes and transforms vital sign information into new and logical forms corresponding to the real phenomena. The technology could be particularly useful for improving situation awareness in settings with high cognitive demand or when users must make quick decisions. This comprehensive review of Visual Patient research is the foundation for an evaluation of the technology in clinical applications, starting with a high-fidelity simulation study in early 2020.

Mass School Shootings in the United States: A Novel Root Cause Analysis Using Lay Press Reports

School shootings comprise a small proportion of childhood deaths from firearms; however, these shootings receive a disproportionately large share of media attention. We conducted a root cause analysis of 2 recent school shootings in the United States using lay press reports. We reviewed 1760 and analyzed 282 articles from the 10 most trusted news sources. We identified 356 factors associated with the school shootings. Policy-level factors, including a paucity of adequate legislation controlling firearm purchase and ownership, were the most common contributing factors to school shootings. Mental illness was a commonly cited person-level factor, and access to firearms in the home and availability of large-capacity firearms were commonly cited environmental factors. Novel approaches, including root cause analyses using lay media, can identify factors contributing to mass shootings. The policy, person, and environmental factors associated with these school shootings should be addressed as part of a multipronged effort to prevent future mass shootings.

A Comparison of Reflective Photoplethysmography for Detection of Heart Rate, Blood Oxygen Saturation, and Respiration Rate at Various Anatomical Locations

Monitoring of vital signs is critical for patient triage and management. Principal assessments of patient conditions include respiratory rate heart/pulse rate and blood oxygen saturation. However, these assessments are usually carried out with multiple sensors placed in different body locations. The aim of this paper is to identify a single location on the human anatomy whereby a single 1 cm × 1 cm non-invasive sensor could simultaneously measure heart rate (HR), blood oxygen saturation (SpO₂), and respiration rate (RR), at rest and while walking. To evaluate the best anatomical location, we analytically compared eight anatomical locations for photoplethysmography (PPG) sensors simultaneously acquired by a single microprocessor at rest and while walking, with a comparison to a commercial pulse oximeter and respiration rate ground truth. Our results show that the forehead produced the most accurate results for HR and SpO₂ both at rest and walking, however, it had poor RR results. The finger recorded similar results for HR and SpO₂, however, it had more accurate RR results. Overall, we found the finger to be the best location for measurement of all three parameters at rest; however, no site was identified as capable of measuring all parameters while walking.

Novel mainstream capnometer system is safe and feasible even under CO2 insufflation during ERCP-related procedure: a pilot study

Background and aims

There is a need to safely achieve conscious sedation during endoscopic retrograde cholangiopancreatography (ERCP). We evaluated the safety and feasibility of a mainstream capnometer system to monitor apnoea during ERCP under CO₂ insufflation.

Methods

Non-intubated adult patients undergoing ERCP-related procedures with intravenous sedation were enrolled. End-tidal CO₂ (EtCO₂) was continuously monitored during the procedure under CO₂ insufflation using a mainstream capnometer system, comprising a capnometer and a specially designed bite block for upper gastrointestinal endoscopy and ERCP. Oxygen saturation (SpO₂) was also monitored continuously during the procedure. In this study, we evaluated the safety and feasibility of the capnometer system.

Results

Eleven patients were enrolled. Measurement of EtCO₂ concentration was possible from the beginning to the end of the procedure in all 11 cases. There was no measurement failure, dislocation of the bite block, or adverse event related to the bite block. Apnoea linked to hypoxaemia occurred five times (mean duration, 174.4 s).

Conclusion

This study confirmed that apnoea was detected earlier than when using a percutaneous oxygen monitor. Measurement of EtCO₂ concentration using the newly developed mainstream capnometer system was feasible and safe even under CO₂ insufflation.

Artificial intelligence systems for complex decision-making in acute care medicine: a review

The integration of artificial intelligence (AI) into acute care brings a new source of intellectual thought to the bedside. This offers great potential for synergy between AI systems and the human intellect already delivering care. This much needed help should be embraced, if proven effective. However, there is a risk that the present role of physicians and nurses as the primary arbiters of acute care in hospitals may be overtaken by computers. While many argue that this transition is inevitable, the process of developing a formal plan to prevent the need to pass control of patient care to computers should not be further delayed.

The first step in the interdiction process is to recognize; the limitations of existing hospital protocols, why we need AI in acute care, and finally how the focus of medical decision making will change with the integration of AI based analysis. The second step is to develop a strategy for changing the focus of medical education to empower physicians to maintain oversight of AI. Physicians, nurses, and experts in the field of safe hospital communication must control the transition to AI integrated care because there is significant risk during the transition period and much of this risk is subtle, unique to the hospital environment, and outside the expertise of AI designers.

AI is needed in acute care because AI detects complex relational time-series patterns within datasets and this level of analysis transcends conventional threshold based analysis applied in hospital protocols in use today. For this reason medical education will have to change to provide healthcare workers with the ability to understand and over-read relational time pattern centered communications from AI. Medical education will need to place less emphasis on threshold decision making and a greater focus on detection, analysis, and the pathophysiologic basis of relational time patterns. This should be an early part of a medical student’s education because this is what their hospital companion (the AI) will be doing.

Effective communication between human and artificial intelligence requires a common pattern centered knowledge base. Experts in safety focused human to human communication in hospitals should lead during this transition process.

Portable multi-parameter electrical impedance tomography for sleep apnea and hypoventilation monitoring: feasibility study

OBJECTIVE

Quantitative ventilation monitoring and respiratory event detection are needed for the diagnosis of sleep apnea and hypoventilation. We developed a portable device with a chest belt, nasal cannula and finger sensor to continuously acquire multi-channel signals including tidal volume, nasal pressure, respiratory effort, body position, snoring sound, ECG and SpO₂. The unique feature of the device is the continuous tidal volume signal obtained from real-time lung ventilation images produced by the electrical impedance tomography (EIT) technique.

APPROACH

The chest belt includes 16 electrodes for real-time time-difference EIT imaging and ECG data acquisitions. It also includes a microphone, accelerometer, gyroscope, magnetometer and pressure sensor to acquire, respectively, snoring sound, respiratory effort, body position and nasal pressure signals. A separate finger sensor is used to measure SpO₂. The minute ventilation signal is derived from the tidal volume signal and respiration rate.

MAIN RESULTS

The experimental results from a conductivity phantom, four swine subjects and one human volunteer show that the developed multi-parameter EIT device could supplement existing polysomnography (PSG) and home sleep test (HST) devices to improve the accuracy of sleep apnea diagnosis. The portable device could be also used as a new tool for continuous hypoventilation monitoring of non-intubated patients with respiratory depression.

SIGNIFICANCE

Following the feasibility study in this paper, future validation studies in comparison with in-lab PSG, HST and end-tidal CO₂ devices are suggested to find its clinical efficacy as a sleep apnea diagnosis and hypoventilation monitoring tool.

Acoustic respiration rate and pulse oximetry-derived respiration rate: a clinical comparison study

Respiration rate (RR) is a critical vital sign that provides early detection of respiratory compromise. The acoustic technique of measuring continuous respiration rate (RR_a) interprets the large airway sound envelope to calculate respiratory rate while pulse oximetry-derived respiratory rate (RR_oxi) interprets modulations of the photoplethsymograph in response to hemodynamic changes during the respiratory cycle. The aim of this study was to compare the performance of these technologies to each other and to a capnography-based reference device. Subjects were asked to decrease their RR from 14 to 4 breaths per minute (BPM) and then increase RR from 14 to 24 BPM. The effects of physiological noise, ambient noise, and head movement and shallow breathing on device performance were also evaluated. The test devices were: (1) RR_a, Radical-7 (Masimo Corporation), (2) RR_oxi, Nellcor™ Bedside Respiratory Patient Monitoring System (Medtronic), and (3) reference device, Capnostream20p™ (Medtronic). All devices were configured with their default settings. Twenty-nine healthy adult subjects were included in the study. During abrupt changes in breathing, overall RR_oxi was accurate for longer periods of time than RR_a; specifically, RR_oxi was more accurate during low and normal RR, but not during high RR. RR_oxi also displayed a value for significantly longer time periods than RR_a when the subjects produced physiological sounds and moved their heads, but not during shallow breathing or ambient noise. RR_oxi may be more accurate than RR_a during development of bradypnea. Also, RR_oxi may display a more reliable RR value during routine patient activities.

Polysomnographic assessment of respiratory disturbance during deep propofol sedation for endoscopic submucosal dissection of gastric tumors

AIM

To investigate that polysomnographic monitoring can accurately evaluate respiratory disturbance incidence during sedation for gastrointestinal endoscopy compare to pulse oximetry alone.

METHODS

This prospective observational study included 10 elderly patients with early gastric cancer undergoing endoscopic submucosal dissection (ESD) under propofol sedation. Apart from routine cardiorespiratory monitoring, polysomnography measurements were acquired. The primary hypothesis was tested by comparing the apnea hypopnea index (AHI), defined as the number of apnea and hypopnea instances per hour during sedation, with and without hypoxemia; hypoxemia was defined as the reduction in oxygen saturation by ≥ 3% from baseline.

RESULTS

Polysomnography (PSG) detected 207 respiratory disturbances in the 10 patients. PSG yielded a significantly greater AHI (10.44 ± 5.68/h) compared with pulse oximetry (1.54 ± 1.81/h, P < 0.001), thus supporting our hypothesis. Obstructive AHI (9.26 ± 5.44/h) was significantly greater than central AHI (1.19 ± 0.90/h, P < 0.001). Compared with pulse oximetry, PSG detected the 25 instances of respiratory disturbances with hypoxemia 107.4 s earlier on average.

CONCLUSION

Compared with pulse oximetry, PSG can better detect respiratory irregularities and thus provide superior AHI values, leading to avoidance of fatal respiratory complications during ESD under propofol-induced sedation.

Faster clinical response to the onset of adverse events: A wearable metacognitive attention aid for nurse triage of clinical alarms

Objective

This study evaluates the potential for improving patient safety by introducing a metacognitive attention aid that enables clinicians to more easily access and use existing alarm/alert information. It is hypothesized that this introduction will enable clinicians to easily triage alarm/alert events and quickly recognize emergent opportunities to adapt care delivery. The resulting faster response to clinically important alarms/alerts has the potential to prevent adverse events and reduce healthcare costs.

Materials and methods

A randomized within-subjects single-factor clinical experiment was conducted in a high-fidelity 20-bed simulated acute care hospital unit. Sixteen registered nurses, four at a time, cared for five simulated patients each. A two-part highly realistic clinical scenario was used that included representative: tasking; information; and alarms/alerts. The treatment condition introduced an integrated wearable attention aid that leveraged metacognition methods from proven military systems. The primary metric was time for nurses to respond to important alarms/alerts.

Results

Use of the wearable attention aid resulted in a median relative within-subject improvement for individual nurses of 118% (W = 183, p = 0.006). The top quarter of relative improvement was 3,303% faster (mean; 17.76 minutes reduced to 1.33). For all unit sessions, there was an overall 148% median faster response time to important alarms (8.12 minutes reduced to 3.27; U = 2.401, p = 0.016), with 153% median improvement in consistency across nurses (F = 11.670, p = 0.001).

Discussion and conclusion

Existing device-centric alarm/alert notification solutions can require too much time and effort for nurses to access and understand. As a result, nurses may ignore alarms/alerts as they focus on other important work. There has been extensive research on reducing alarm frequency in healthcare. However, alarm safety remains a top problem. Empirical observations reported here highlight the potential of improving patient safety by supporting the meta-work of checking alarms.

Evaluating performance of early warning indices to predict physiological instabilities

Patient monitoring algorithms that analyze multiple features from physiological signals can produce an index that serves as a predictive or prognostic measure for a specific critical health event or physiological instability. Classical detection metrics such as sensitivity and positive predictive value are often used to evaluate new patient monitoring indices for such purposes, but since these metrics do not take into account the continuous nature of monitoring, the assessment of a warning system to notify a user of a critical health event remains incomplete. In this article, we present challenges of assessing the performance of new warning indices and propose a framework that provides a more complete characterization of warning index performance predicting a critical event that includes the timeliness of the warning. The framework considers 1) an assessment of the sensitivity to provide a notification within a meaningful time window, 2) the cumulative sensitivity leading up to an event, 3) characteristics on if the warning stays on until the event occurs once a warning has been activated, and 4) the distribution of warning times and the burden of additional warnings (e.g., false-alarm rate) throughout monitoring that may or may not be associated with the event of interest. Using an example from an experimental study of hemorrhage, we examine how this characterization can differentiate two warning systems in terms of timeliness of warnings and warning burden.

Understanding Phenotypes of Obstructive Sleep Apnea: Applications in Anesthesia, Surgery, and Perioperative Medicine

Obstructive sleep apnea (OSA) is a prevalent sleep-disordered breathing with potential long-term major neurocognitive and cardiovascular sequelae. The pathophysiology of OSA varies between individuals and is composed of different underlying mechanisms. Several components including the upper airway anatomy, effectiveness of the upper airway dilator muscles such as the genioglossus, arousal threshold of the individual, and inherent stability of the respiratory control system determine the pathogenesis of OSA. Their recognition may have implications for the perioperative health care team. For example, OSA patients with a high arousal threshold are likely to be sensitive to sedatives and narcotics with a higher risk of respiratory arrest in the perioperative period. Supplemental oxygen therapy can help to stabilize breathing in OSA patients with inherent respiratory instability. Avoidance of supine position can minimize airway obstruction in patients with a predisposition to upper airway collapse in this posture. In this review, the clinically relevant endotypes and phenotypes of OSA are described. Continuous positive airway pressure (CPAP) therapy is the treatment of choice for most patients with OSA but tolerance and adherence can be a problem. Patient-centered individualized approaches to OSA management will be the focus of future research into developing potential treatment options that will help decrease the disease burden and improve treatment effectiveness.

Multisensor data fusion for enhanced respiratory rate estimation in thermal videos

Scientific studies have demonstrated that an atypical respiratory rate (RR) is frequently one of the earliest and major indicators of physiological distress. However, it is also described in the literature as "the neglected vital parameter", mainly due to shortcomings of clinical available monitoring techniques, which require attachment of sensors to the patient's body. The current paper introduces a novel approach that uses multisensor data fusion for an enhanced RR estimation in thermal videos. It considers not only the temperature variation around nostrils and mouth, but the upward and downward movement of both shoulders. In order to analyze the performance of our approach, two experiments were carried out on five healthy candidates. While during phase A, the subjects breathed normally, during phase B they simulated different breathing patterns. Thoracic effort was the gold standard elected to validate our algorithm. Our results show an excellent agreement between infrared thermography (IRT) and ground truth. While in phase A a mean correlation of 0.983 and a root-mean-square error of 0.240 bpm (breaths per minute) was obtained, in phase B they hovered around 0.995 and 0.890 bpm, respectively. In sum, IRT may be a promising clinical alternative to conventional sensors. Additionally, multisensor data fusion contributes to an enhancement of RR estimation and robustness.