Assessing Physical Therapists' Outdoor Walking Recommendations and Neighborhood Walkability for Older Adults.

BACKGROUND/OBJECTIVES: Neighborhood walkability is the extent to which built and social environments support walking. Walkability influences older adults' participation in outdoor physical activity. Identifying factors that influence physical therapists' (PTs) decisions about prescribing outdoor walking is needed, especially for those who are aging in place. The purpose of this study is to describe the neighborhood walkability knowledge, perceptions, and assessment practices of PTs who work with community-dwelling older adults. METHODS: A cross-sectional survey was sent via email to 5,000 PTs nationwide. The 40-item survey assessed walking prescriptions, walkability perceptions and assessments, and gathered demographic data. Categorical variables were compared using Chi-square analyses. RESULTS: Using a total of 122 PTs who worked in outpatient geriatric physical therapy settings, a significant difference was found between perceptions of whether PTs should assess walkability and whether they actually assess walkability (χ2 = 78.7, p < .001). Decisions to prescribe outdoor walking were influenced by the availability (n = 79, 64.8%) and maintenance (n = 11, 9.0%) of sidewalks, crime (n = 9, 7.4%), terrain (n = 7, 5.7%), and aesthetics (n = 6, 4.9%). Objective walkability measures were not used by the respondents. CONCLUSION: When considering the assessment of walkability, PTs prioritize the built environment over the social environment. Although most believe it is the responsibility of the PT to assess walkability, most do not. Significance/Implications: Assessment of walkability may allow PTs to identify barriers and make more informed recommendations concerning outdoor walking for older adults. Objective measures are available for PTs when prescribing outdoor walking.

Bag-Valve-Mask Ventilation and Survival From Out-of-Hospital Cardiac Arrest: A Multicenter Study.

BACKGROUND: Few studies have measured ventilation during early cardiopulmonary resuscitation (CPR) before advanced airway placement. Resuscitation guidelines recommend pauses after every 30 chest compressions to deliver ventilations. The effectiveness of bag-valve-mask ventilation delivered during the pause in chest compressions is unknown. We sought to determine: (1) the incidence of lung inflation with bag-valve-mask ventilation during 30:2 CPR; and (2) the association of ventilation with outcomes after out-of-hospital cardiac arrest. METHODS: We studied patients with out-of-hospital cardiac arrest from 6 sites of the Resuscitation Outcomes Consortium CCC study (Trial of Continuous Compressions versus Standard CPR in Patients with Out-of-Hospital Cardiac Arrest). We analyzed patients assigned to the 30:2 CPR arm with ≥2 minutes of thoracic bioimpedance signal recorded with a cardiac defibrillator/monitor. Detectable ventilation waveforms were defined as having a bioimpedance amplitude ≥0.5 Ω (corresponding to ≥250 mL VT) and a duration ≥1 s. We defined a chest compression pause as a 3- to 15-s break in chest compressions. We compared the incidence of ventilation and outcomes in 2 groups: patients with ventilation waveforms in <50% of pauses (group 1) versus those with waveforms in ≥50% of pauses (group 2). RESULTS: Among 1976 patients, the mean age was 65 years; 66% were male. From the start of chest compressions until advanced airway placement, mean±SD duration of 30:2 CPR was 9.8±4.9 minutes. During this period, we identified 26 861 pauses in chest compressions; 60% of patients had ventilation waveforms in <50% of pauses (group 1, n=1177), and 40% had waveforms in ≥50% of pauses (group 2, n=799). Group 1 had a median of 12 pauses and 2 ventilations per patient versus group 2, which had 12 pauses and 12 ventilations per patient. Group 2 had higher rates of prehospital return of spontaneous circulation (40.7% versus 25.2%; P<0.0001), survival to hospital discharge (13.5% versus 4.1%; P<0.0001), and survival with favorable neurological outcome (10.6% versus 2.4%; P<0.0001). These associations persisted after adjustment for confounders. CONCLUSIONS: In this study, lung inflation occurred infrequently with bag-valve-mask ventilation during 30:2 CPR. Lung inflation in ≥50% of pauses was associated with improved return of spontaneous circulation, survival, and survival with favorable neurological outcome.

THE COMPENSATORY RESERVE INDEX FOR PREDICTING HEMORRHAGIC SHOCK IN PREHOSPITAL TRAUMA.

ABSTRACT: Background: The compensatory reserve index (CRI) is a noninvasive, continuous measure designed to detect intravascular volume loss. CRI is derived from the pulse oximetry waveform and reflects the proportion of physiologic reserve remaining before clinical hemodynamic decompensation. Methods: In this prospective, observational, prehospital cohort study, we measured CRI in injured patients transported by emergency medical services (EMS) to a single Level I trauma center. We determined whether the rolling average of CRI values over 60 s (CRI trend [CRI-T]) predicts in-hospital diagnosis of hemorrhagic shock, defined as blood product administration in the prehospital setting or within 4 h of hospital arrival. We hypothesized that lower CRI-T values would be associated with an increased likelihood of hemorrhagic shock and better predict hemorrhagic shock than prehospital vital signs. Results: Prehospital CRI was collected on 696 adult trauma patients, 21% of whom met our definition of hemorrhagic shock. The minimum CRI-T was 0.14 (interquartile range [IQR], 0.08-0.31) in those with hemorrhagic shock and 0.31 (IQR 0.15-0.50) in those without ( P = <0.0001). The positive likelihood ratio of a CRI-T value <0.2 predicting hemorrhagic shock was 1.85 (95% confidence interval [CI], 1.55-2.22). The area under the ROC curve (AUC) for the minimum CRI-T predicting hemorrhagic shock was 0.65 (95% CI, 0.60-0.70), which outperformed initial prehospital HR (0.56; 95% CI, 0.50-0.62) but underperformed EMS systolic blood pressure and shock index (0.74; 95% CI, 0.70-0.79 and 0.72; 95% CI, 0.67-0.77, respectively). Conclusions: Low prehospital CRI-T predicts blood product transfusion by EMS or within 4 hours of hospital arrival but is less prognostic than EMS blood pressure or shock index. The evaluated version of CRI may be useful in an austere setting at identifying injured patients that require the most significant medical resources. CRI may be improved with noise filtering to attenuate the effects of vibration and patient movement.

Characterization of non-cardiac arrest PulsePoint activations in public and private settings.

BACKGROUND: Geospatial smartphone application alert systems are used in some communities to crowdsource community response for out-of-hospital cardiac arrest (OHCA). Although the clinical focus of this strategy is OHCA, dispatch identification of OHCA is imperfect so that activation may occur for the non-arrest patient. The frequency and clinical profile of such non-arrest patients has not been well-investigated. METHODS: We undertook a prospective 3-year cohort investigation of patients for whom a smartphone geospatial application was activated for suspected OHCA in four United States communities (total population ~1 million). The current investigation evaluates those patients with an activation for suspected OHCA who did not experience cardiac arrest. The volunteer response cohort included off-duty, volunteer public safety personnel (verified responders) notified regardless of location (public or private) and laypersons notified to public locations. The study linked the smartphone application information with the EMS records to report the frequency, condition type, and EMS treatment for these non-arrest patients. RESULTS: Of 1779 calls where volunteers were activated, 756 had suffered OHCA, resulting in 1023 non-arrest patients for study evaluation. The most common EMS assessments were syncope (15.9%, n=163), altered mental status (15.5%, n=159), seizure (14.3%, n=146), overdose (13.0%, n=133), and choking (10.5%, n=107). The assessment distribution was similar for private and public locations. Overall, the most common EMS interventions included placement of an intravenous line (43.1%, n=441), 12-Lead ECG(27.9%, n=285), naloxone treatment (9.8%, n=100), airway or ventilation assistance (8.7%, n=89), and oxygen administration (6.6%, n=68). CONCLUSIONS: More than half of patients activated for suspected OHCA had conditions other than cardiac arrest. A subset of these conditions may benefit from earlier care that could be provided by both layperson and public safety volunteers if they were appropriately trained and equipped.

Prediction of Shock-Refractory Ventricular Fibrillation During Resuscitation of Out-of-Hospital Cardiac Arrest.

BACKGROUND: Out-of-hospital cardiac arrest due to shock-refractory ventricular fibrillation (VF) is associated with relatively poor survival. The ability to predict refractory VF (requiring ≥3 shocks) in advance of repeated shock failure could enable preemptive targeted interventions aimed at improving outcome, such as earlier administration of antiarrhythmics, reconsideration of epinephrine use or dosage, changes in shock delivery strategy, or expedited invasive treatments. METHODS: We conducted a cohort study of VF out-of-hospital cardiac arrest to develop an ECG-based algorithm to predict patients with refractory VF. Patients with available defibrillator recordings were randomized 80%/20% into training/test groups. A random forest classifier applied to 3-s ECG segments immediately before and 1 minute after the initial shock during cardiopulmonary resuscitation was used to predict the need for ≥3 shocks based on singular value decompositions of ECG wavelet transforms. Performance was quantified by area under the receiver operating characteristic curve. RESULTS: Of 1376 patients with VF out-of-hospital cardiac arrest, 311 (23%) were female, 864 (63%) experienced refractory VF, and 591 (43%) achieved functional neurological survival. Total shock count was associated with decreasing likelihood of functional neurological survival, with a relative risk of 0.95 (95% CI, 0.93-0.97) for each successive shock (P<0.001). In the 275 test patients, the area under the receiver operating characteristic curve for predicting refractory VF was 0.85 (95% CI, 0.79-0.89), with specificity of 91%, sensitivity of 63%, and a positive likelihood ratio of 6.7. CONCLUSIONS: A machine learning algorithm using ECGs surrounding the initial shock predicts patients likely to experience refractory VF, and could enable rescuers to preemptively target interventions to potentially improve resuscitation outcome.

Age, sex, and survival following ventricular fibrillation cardiac arrest: A mechanistic evaluation of the ECG waveform.

BACKGROUND: Studies of outcome differences by sex in out-of-hospital cardiac arrest (OHCA) have produced mixed results that may depend on age, a potential surrogate for menopausal status. OBJECTIVE: We used quantitative measures of ventricular fibrillation (VF) waveforms - indicators of the myocardium's physiology - to assess whether survival differences according to sex and age group may be mediated via a biologic mechanism. METHODS: We conducted a cohort study of VF-OHCA in a metropolitan EMS system. We used multivariable logistic regression to assess the association of survival to hospital discharge with sex and age group (<55, ≥55 years). We determined the proportion of outcome difference mediated by VF waveform measures: VitalityScore and amplitude spectrum area (AMSA). RESULTS: Among 1526 VF-OHCA patients, the average age was 62 years, and 29% were female. Overall, younger women were more likely to survive than younger men (survival 67% vs 54%, p = 0.02), while survival among older women and older men did not differ (40% vs 44%, p = 0.3). Adjusting for Utstein characteristics, women <55 compared to men <55 had greater odds of survival to hospital discharge (OR = 1.93, 95% CI 1.23-3.09), an association not observed between the ≥55 groups. Waveform measures were more favorable among women and mediated some of the beneficial association between female sex and survival among those <55 years: 47% for VitalityScore and 25% for AMSA. CONCLUSIONS: Women <55 years were more likely to survive than men <55 years following VF-OHCA. The biologic mechanism represented by VF waveform mediated some, though not all, of the outcome difference.

Instantaneous amplitude: Association of ventricular fibrillation waveform measures at time of shock with outcome in out-of-hospital cardiac arrest.

BACKGROUND: Prompt defibrillation is key to successful resuscitation from ventricular fibrillation out-of-hospital cardiac arrest (VF-OHCA). Preliminary evidence suggests that the timing of shock relative to the amplitude of the VF ECG waveform may affect the likelihood of resuscitation. We investigated whether the VF waveform amplitude at the time of shock (instantaneous amplitude) predicts outcome independent of other validated waveform measures. METHODS: We conducted a retrospective study of VF-OHCA patients ≥18 old. We evaluated three VF waveform measures for each shock: instantaneous amplitude at the time of shock, and maximum amplitude and amplitude spectrum area (AMSA) over a 3-s window preceding the shock. Linear mixed-effects modeling was used to determine whether instantaneous amplitude was associated with shock-specific return of organized rhythm (ROR) or return of spontaneous circulation (ROSC) independent of maximum amplitude or AMSA. RESULTS: The 566 eligible patients received 1513 shocks, resulting in ROR of 62.0% (938/1513) and ROSC of 22.3% (337/1513). In unadjusted regression, an interquartile increase in instantaneous amplitude was associated with ROR (Odds ratio [OR] [95% confidence interval] = 1.27 [1.11-1.45]) and ROSC (OR = 1.27 [1.14-1.42]). However, instantaneous amplitude was not associated with ROR (OR = 1.13 [0.97-1.30]) after accounting for maximum amplitude, nor with ROR (OR = 1.00 [0.87-1.15]) or ROSC (OR = 1.05 [0.93-1.18]) after accounting for AMSA. By contrast, AMSA and maximum amplitude remained independently associated with ROR and ROSC. CONCLUSIONS: We did not observe an independent association between instantaneous amplitude and shock-specific outcomes. Efforts to time shock to the maximal amplitude of the VF waveform are unlikely to affect resuscitation outcome.

Balance performance and grip strength as predictors of cognitive function among community-dwelling older adults in the USA.

Objectives: To investigate how balance and grip strength predicts the probability of cognitive function impairment (i.e., executive function: mild and mild-to-moderate impairment, and delayed recall) over eight years in community-dwelling older adults in the US, controlling for sex and race/ethnicity. Methods: The National Health and Aging Trends Study dataset (2011 - 2018) was employed. Dependent variables included the Clock Drawing Test (Executive Function) and Delayed Word Recall Test. Longitudinal ordered logistic regression examined the association between cognitive function and predictors (i.e., balance and grip strength) over eight waves (n=9800, 1,225 per wave). Results: Those who could complete side-by-side standing and semi-tandem tasks were 33% and 38% less likely to have mild or mild-to-moderate executive function impairment, respectively, relative to those who could not complete these tests. One score decrease in grip strength increased the executive function impairment risk by 13% (Odds Ratio: 0.87, CI: 0.79-0.95). Those who completed the side-by-side tasks were 35% (Odds Ratio: 0.65, CI: 0.44-0.95) less likely to experience delayed recall impairments than those who could not complete this test. With one score decrease in grip strength, the risk of delayed recall impairment was increased by 11% (OR: 0.89, CI: 0.80-1.00). Conclusions: A combination of these two simple tests (i.e., semi-tandem stance and grip strength) can screen for cognitive impairment among community-dwelling older adults to identify people with mild and mild-to-moderate cognitive impairment in clinical settings.

Determinants of acute care discharge in adults with chronic obstructive pulmonary disease.

CONCLUSIONS: In adults with COPD basic mobility scores on the AM-PAC "6-clicks" measure completed at discharge had the best sensitivity and specificity for predicting discharge to home and need for rehab services.

Associations Between Cognitive Function, Balance, and Gait Speed in Community-Dwelling Older Adults with COPD.

BACKGROUND AND PURPOSE: Older adults with chronic obstructive pulmonary disease (COPD) are at risk for physical and cognitive impairment. Cognitive function is associated with falls in older adults. However, it is unknown whether a relationship exists between cognitive function and falls in patients with COPD. The aim of this study was to examine the relationships between cognitive function, balance, and gait speed in older adults with COPD. PATIENTS AND METHODS: A secondary analysis was performed using data from the 2010 wave of the Health and Retirement Study (HRS). Cognitive (immediate and delayed recall, executive function) and physical (gait speed, tandem balance time) measure data were extracted for older adults with COPD (n = 382) and an age-matched control group without COPD (n = 382) who met inclusion/exclusion criteria. Multivariate linear regression modeling was performed to examine associations between cognitive function and mobility or balance while controlling for age, gender, body mass index, grip strength, and education. RESULTS: In older adults with COPD, delayed recall was significantly associated with tandem balance performance (ß= 1.42, P < .05). Other cognitive measures were not associated with gait speed or balance. CONCLUSION: In older adults with COPD, one of four cognitive functions was associated with a static standing balance task. Screening of cognitive function, specifically delayed recall, should be a part of the management of falls in this population.

Continuous assessment of ventricular fibrillation prognostic status during CPR: Implications for resuscitation.

BACKGROUND: Ventricular fibrillation (VF) waveform measures reflect myocardial physiologic status. Continuous assessment of VF prognosis using such measures could guide resuscitation, but has not been possible due to CPR artifact in the ECG. A recently-validated VF measure (termed VitalityScore), which estimates the probability (0-100%) of return-of-rhythm (ROR) after shock, can assess VF during CPR, suggesting potential for continuous application during resuscitation. OBJECTIVE: We evaluated VF using VitalityScore to characterize VF prognostic status continuously during resuscitation. METHODS: We characterized VF using VitalityScore during 60 seconds of CPR and 10 seconds of subsequent pre-shock CPR interruption in patients with out-of-hospital VF arrest. VitalityScore utility was quantified using area under the receiver operating characteristic curve (AUC). VitalityScore trends over time were estimated using mixed-effects models, and associations between trends and ROR were evaluated using logistic models. A sensitivity analysis characterized VF during protracted (100-second) periods of CPR. RESULTS: We evaluated 724 VF episodes among 434 patients. After an initial decline from 0-8 seconds following VF onset, VitalityScore increased slightly during CPR from 8-60 seconds (slope: 0.18%/min). During the first 10 seconds of subsequent pre-shock CPR interruption, VitalityScore declined (slope: -14%/min). VitalityScore predicted ROR throughout CPR with AUCs 0.73-0.75. Individual VitalityScore trends during 8-60 seconds of CPR were marginally associated with subsequent ROR (adjusted odds ratio for interquartile slope change (OR) = 1.10, p = 0.21), and became significant with protracted (100 seconds) CPR duration (OR = 1.28, p = 0.006). CONCLUSION: VF prognostic status can be continuously evaluated during resuscitation, a development that could translate to patient-specific resuscitation strategies.

A method for continuous rhythm classification and early detection of ventricular fibrillation during CPR.

AIM: We developed a method which continuously classifies the ECG rhythm during CPR in order to guide clinical care. METHODS: We conducted a retrospective study of 432 patients treated following out-of-hospital cardiac arrest. Continuous ECG sequences from two-minute CPR cycles were extracted from defibrillator recordings and further divided into five-second clips. We developed an algorithm using wavelet analysis, hidden semi-Markov modeling, and random forest classification. The algorithm classifies individual clips as asystole, organized rhythm, ventricular fibrillation, or Inconclusive while integrating information from previous clips. Classifications were compared to manual annotations to estimate accuracy in an independent validation dataset. Continuous sequences were classified as shockable, non-shockable, or Inconclusive; classifications were used to compute shock sensitivity and specificity. RESULTS: Of 432 patient-cases, 290 were used for development and 142 for validation. In the 12,294 validation ECG clips during CPR, accuracies were 0.88 (95% CI 0.85-0.91) for asystole, 0.98 (95% CI 0.98-0.99) for organized rhythm, and 0.97 (95% CI 0.96-0.97) for ventricular fibrillation, with 43% classified as Inconclusive. Of 457 continuous sequences, shock sensitivity was 0.90 (95% CI 0.86-0.93), shock specificity was 0.98 (95% CI 0.93-0.99), and 7% were Inconclusive. Median delay to ventricular fibrillation recognition was 10 (IQR 5-32) seconds. CONCLUSION: A novel algorithm continuously classified the primary resuscitation rhythms-asystole, organized rhythms, and ventricular fibrillation-with 88-98% accuracy, enabling accurate shock advisory guidance during most two-minute CPR cycles. Additional investigation is required to understand how algorithm implementation could affect rescuer actions and clinical outcomes.

A pilot evaluation of respiratory mechanics during prehospital manual ventilation.

INTRODUCTION: Respiratory mechanics, such as tidal volume (VT) and inspiratory pressures, may affect outcome in hospitalized patients with respiratory failure. Little is known about respiratory mechanics in the prehospital setting. METHODS: In this prospective, pilot investigation of patients receiving prehospital advanced airway placement, paramedics applied a device to measure respiratory mechanics. We evaluated tidal volume (VT) per predicted body weight (VTPBW) to determine the proportion of breaths within the lung-protective range of 4-10 mL/kg per PBW overall, according to ventilation bag volume (large versus small) and cardiac arrest status (active CPR, post-ROSC, non-arrest). RESULTS: Over 16-months, 7371 post-intubation breaths were measured in 54 patients, 32 patients with cardiac arrest and 22 with other conditions. Paramedics ventilated 19 patients with a small bag and 35 patients with a large bag. Overall, mean VT was 435 mL (95% CI 403, 467); VTPBW was 7.0 mL/kg (95% CI 6.4, 7.6) with 75% within the lung-protective range. Mean VTPBW and peak pressure differed according to arrest status (absolute difference -0.36 mL/kg and 32 cmH2O for active CPR compared to post-ROSC), though not according to bag size. CONCLUSIONS: We observed that measuring respiratory mechanics in the prehospital setting was feasible. Tidal volumes were generally delivered within a safe range. Respiratory mechanics varied most significantly with active CPR with lower VTPBW and higher peak pressures, though did not seem to be affected by bag size. Future work might examine the relationship between respiratory mechanics and outcomes, which may identify opportunities to improve clinical outcomes.

Use of activPAL to Measure Physical Activity in Community-Dwelling Older Adults: A Systematic Review.

Objective: To perform a systematic review of the literature to describe how the activPAL accelerometer has been used to measure physical activity (PA) in community-dwelling older adults to standardize collection of PA data in this population using this thigh-worn accelerometer. Data Sources: A comprehensive search of the following databases was completed: Cumulative Index to Nursing and Allied Health Complete, Embase, OVID Medicine, PubMed/Web of Science, and Scopus. Study Selection: Studies were included if published before August 1, 2020, were written in English, and used activPAL to measure PA in community-dwelling, noninstitutionalized adults 65 years or older. Titles and abstracts were independently reviewed, and the decision to include or exclude was made by 100% consensus. Data Extraction: Three research team members independently extracted the data from included studies. Extracted data were compared and discussed with relevant information included. Study quality was assessed using the Quality Assessment Tool for Observational Cohort and Cross-sectional Studies. Data Synthesis: A total of 7 articles met the inclusion criteria. Three of the 7 studies used activPAL to report steps/d, ranging from 864-15847 steps/d. Time spent stepping or walking was reported by 4 studies using various units. Sit-to-stand transitions were reported by 4 studies, averaging 10-63 transitions/d. Sedentary time was assessed in 6 studies, whereas moderate to vigorous physical activity was not measured using activPAL in any study. Conclusions: The activPAL is most often used to collect data on step count and walking, sit-to-stand transitions, and sedentary time in community-dwelling older adults.

Perceived Neighborhood Walkability is Associated with Recent Falls in Urban Dwelling Older Adults.

BACKGROUND AND PURPOSE: In rural communities, perceptions of neighborhood walkability, the rating of how easy it is to walk in an area, influence engagement in physical activity outside the home. This has not been studied in older adults residing in urban settings. Additionally, it is not known how perceived walkability is associated with falls. Therefore, the purpose of this study was to first describe the perceptions of neighborhood walkability in urban-dwelling older adults based on recent fall history and then examine associations between recent falls and neighborhood walkability constructs after controlling for fall risk factors. METHODS: Urban-dwelling older adults (N = 132) 65 years and older without cognitive dysfunction or uncontrolled comorbidity completed a survey assessing health status, physical activity, and walkability using the Neighborhood Environment Walkability Scale-Abbreviated. Group assignment was based on recent fall history. Between-group comparisons of demographic and walkability constructs were completed using analysis of variance. Logistic regression was used to examine associations between walkability constructs and recent falls after controlling for covariates. RESULTS AND DISCUSSION: Poorer perception of land use was significantly associated with recent falls. Questions assessing the ease of walking to a store or transit stop may be valuable in understanding fall risk in older adults living in urban settings. CONCLUSIONS: Perceptions of neighborhood walkability are lower in urban-dwelling older adults with a history of falling.

Cerebral Oximetry during Out-of-Hospital Resuscitation: Pilot Study of First Responder Implementation.

Background: Anoxic brain injury is a common mode of death following out-of-hospital cardiac arrest (OHCA). We assessed the course of regional cerebral oxygen saturation (rSO2) at the outset and during first responder resuscitation to understand its relationship with return of spontaneous circulation (ROSC) and functional survival. Methods: We undertook a prospective observational investigation of adult OHCA patients treated by a first-responder EMS agency in King County, WA. Cerebral oximetry was performed using the SenSmart® Model X-100 Universal Oximetry System (Nonin Medical, Inc). We determined cerebral oximetry rSO2 overall and stratified according to ROSC and favorable survival status defined by Cerebral Performance Category (CPC) of 1-2. Results: Among the 59 OHCA cases enrolled, 47% (n = 28) achieved ROSC and 14% (n = 8) survived with CPC 1-2. On average, initial rSO2 cerebral oximetry was 41% and was not different at the outset according to return of spontaneous circulation (ROSC) or survival status. Within 5 minutes of first responder resuscitation, those who would subsequently achieve ROSC had a higher rSO2 than those who would not achieve ROSC (51% vs. 43%, p = 0.03). Among patients who achieved ROSC, those who would survive with CPC 1-2 had a higher rSO2 cerebral oximetry following ROSC than nonsurvivors (74% vs. 60%, p = 0.04 at 5 minutes post ROSC), a difference that was not evident in the minutes prior to ROSC (55% vs. 51% at 3 minutes prior to ROSC, p = 0.5). Conclusion: In this observational study, where first responders applied cerebral oximetry, higher rSO2 during the course of care predicted ROSC among all patients and predicted favorable survival among those who achieved ROSC. Future investigation should evaluate whether and how treatments might modify rSO2 and in turn may influence prognosis.

Screening recall in older cancer survivors detects differences in balance and mobility.

PURPOSE: Cognitive impairments have been reported by up to two-thirds of cancer survivors whose primary cancer did not occur in the central nervous system. Physical impairments as sequelae of cancer-related cognitive impairment (CRCI) have not been well described in previous studies. Furthermore, there is scarcity of literature describing differences among physical performance in those with and without CRCI. The purpose of this study is to examine the differences in physical function of older cancer survivors based on cognitive ability to determine if physical performance differs when different cognitive screening measures are employed. METHODS: Adults age 65 + with a history of cancer from the 2010 Health and Retirement Study (n = 1,953) were assigned to groups according to their cognitive ability. Between-group demographic, mobility, and cognitive differences were analyzed using chi-squared and t tests. Recall and orientation were used as cognitive variables, and physical performance outcomes included gait speed, balance, and grip strength. RESULTS: Respondents with Low Recall had more impaired balance (semi-tandem, tandem) (p < .05) and slower gait speeds (p < .05). Respondents that were Not-Oriented had slower gait speed (p < .05). Between-group differences in demographics were found by recall and orientation groups. CONCLUSIONS: Impairments in balance and gait speed are able to be detected when recall is screened in a population of older cancer survivors. When assessing how physical mobility is related to fall risk, a screen of cognition should go beyond just orientation.

Machine learning and feature engineering for predicting pulse presence during chest compressions.

Current resuscitation protocols require pausing chest compressions during cardiopulmonary resuscitation (CPR) to check for a pulse. However, pausing CPR when a patient is pulseless can worsen patient outcomes. Our objective was to design and evaluate an ECG-based algorithm that predicts pulse presence with or without CPR. We evaluated 383 patients being treated for out-of-hospital cardiac arrest with real-time ECG, impedance and audio recordings. Paired ECG segments having an organized rhythm immediately preceding a pulse check (during CPR) and during the pulse check (without CPR) were extracted. Patients were randomly divided into 60% training and 40% test groups. From training data, we developed an algorithm to predict the clinical pulse presence based on the wavelet transform of the bandpass-filtered ECG. Principal component analysis was used to reduce dimensionality, and we then trained a linear discriminant model using three principal component modes as input features. Overall, 38% (351/912) of checks had a spontaneous pulse. AUCs for predicting pulse presence with and without CPR on test data were 0.84 (95% CI (0.80, 0.88)) and 0.89 (95% CI (0.86, 0.92)), respectively. This ECG-based algorithm demonstrates potential to improve resuscitation by predicting the presence of a spontaneous pulse without pausing CPR with moderate accuracy.

Insights From the Ventricular Fibrillation Waveform Into the Mechanism of Survival Benefit From Bystander Cardiopulmonary Resuscitation.

Background The mechanism by which bystander cardiopulmonary resuscitation (CPR) improves survival following out-of-hospital cardiac arrest is unclear. We hypothesized that ventricular fibrillation (VF) waveform measures, as surrogates of myocardial physiology, mediate the relationship between bystander CPR and survival. Methods and Results We performed a retrospective cohort study of adult, bystander-witnessed patients with out-of-hospital cardiac arrest with an initial rhythm of VF who were treated by a metropolitan emergency medical services system from 2005 to 2018. Patient, resuscitation, and outcome variables were extracted from emergency medical services and hospital records. A total of 3 VF waveform measures (amplitude spectrum area, peak frequency, and median peak amplitude) were computed from a 3-second ECG segment before the initial shock. Multivariable logistic regression estimated the association between bystander CPR and survival to hospital discharge adjusted for Utstein elements. Causal mediation analysis quantified the proportion of survival benefit that was mediated by each VF waveform measure. Of 1069 patients, survival to hospital discharge was significantly higher among the 814 patients who received bystander CPR than those who did not (0.52 versus 0.43, respectively; P<0.01). The multivariable-adjusted odds ratio for bystander CPR and survival was 1.6 (95% CI, 1.2, 2.1), and each VF waveform measure attenuated this association. Depending on the specific waveform measure, the proportion of mediation varied: 53% for amplitude spectrum area, 31% for peak frequency, and 29% for median peak amplitude. Conclusions Bystander CPR correlated with more robust initial VF waveform measures, which in turn mediated up to one-half of the survival benefit associated with bystander CPR. These results provide insight into the biological mechanism of bystander CPR in VF out-of-hospital cardiac arrest.

Physical function measurement in older long-term cancer survivors.

OBJECTIVE: To establish reliability, validity, and minimal detectable change in measures of function in older long-term cancer survivors. METHODS: Older cancer survivors were recruited to perform functional measures; 5 Times Sit-to-Stand (5xSTS), 30-second Timed Chair Rise (30sTCR), Short Physical Performance Battery (SPPB), Physical Performance Test-7 (PPT-7). Two testing sessions were completed two weeks apart. Test-retest reliability was examined using the intraclass correlation coefficient (ICC2,1), convergent and discriminant validity using Spearman's rho and Minimal Detectable Change (MDC95) was calculated. RESULTS: Forty-seven older long-term cancer survivors participated. Test-retest reliability was good for 5xSTS (ICC2,1=0.86), 30sTCR (ICC2,1=0.89), and SPPB (ICC2,1=0.85) and poor for PPT-7 (ICC2,1=0.48). Both convergent and discriminant validity was established. CONCLUSIONS: SPPB, 5xSTS, and 30sTCR are reliable and valid tools to measure function in older long-term cancer survivors. MDC95 values were larger than those reported in geriatrics and should be interpreted with caution. Residual effects of cancer treatment, comorbidity, and physical inactivity may contribute to decreased physical function in older long-term cancer survivors, therefore valid and reliable measures like SPPB and the timed chair rise tests should be used objectively measure function throughout the survivorship spectrum.