Resumption of Cardiac Activity after Withdrawal of Life-Sustaining Measures.

BACKGROUND: The minimum duration of pulselessness required before organ donation after circulatory determination of death has not been well studied. METHODS: We conducted a prospective observational study of the incidence and timing of resumption of cardiac electrical and pulsatile activity in adults who died after planned withdrawal of life-sustaining measures in 20 intensive care units in three countries. Patients were intended to be monitored for 30 minutes after determination of death. Clinicians at the bedside reported resumption of cardiac activity prospectively. Continuous blood-pressure and electrocardiographic (ECG) waveforms were recorded and reviewed retrospectively to confirm bedside observations and to determine whether there were additional instances of resumption of cardiac activity. RESULTS: A total of 1999 patients were screened, and 631 were included in the study. Clinically reported resumption of cardiac activity, respiratory movement, or both that was confirmed by waveform analysis occurred in 5 patients (1%). Retrospective analysis of ECG and blood-pressure waveforms from 480 patients identified 67 instances (14%) with resumption of cardiac activity after a period of pulselessness, including the 5 reported by bedside clinicians. The longest duration after pulselessness before resumption of cardiac activity was 4 minutes 20 seconds. The last QRS complex coincided with the last arterial pulse in 19% of the patients. CONCLUSIONS: After withdrawal of life-sustaining measures, transient resumption of at least one cycle of cardiac activity after pulselessness occurred in 14% of patients according to retrospective analysis of waveforms; only 1% of such resumptions were identified at the bedside. These events occurred within 4 minutes 20 seconds after a period of pulselessness. (Funded by the Canadian Institutes for Health Research and others.).

A new method of pulse control in cardiopulmonary resuscitation; Continuous femoral pulse check.

OBJECTIVES: The reliability of manual pulse checks has been questioned but is still recommended in cardiopulmonary resuscitation (CPR) guidelines. The aim is to compare the 10-s carotid pulse check (CPC) between heart massage cycles with the continuous femoral pulse check (CoFe PuC) in CPR, and to propose a better location to shorten the interruption times for pulse check. METHODS: A prospective study was conducted on 117 Non-traumatic CPR patients between January 2020 and January 2022. A total of 702 dependent pulse measurements were executed, where carotid and femoral pulses were simultaneously assessed. Cardiac ultrasound, end-tidal CO2, saturation, respiration, and blood pressure were employed for pulse validation. RESULTS: The decision time for determining the presence of a pulse in the last cycle of CPR was 3.03 ± 1.26 s for CoFe PuC, significantly shorter than the 10.31 ± 5.24 s for CPC. CoFe PuC predicted the absence of pulse with 74% sensitivity and 88% specificity, while CPC predicted the absence of pulse with 91% sensitivity and 61% specificity. CONCLUSION: CoFe PuC provides much earlier and more effective information about the pulse than CPC. This shortens the interruption times in CPR. CoFe PuC should be recommended as a new and useful method in CPR guidelines.

Dielectric modulation strategy of carbon nanotube field effect transistors based pressure sensor: towards precise monitoring of human pulse.

Continuous monitoring of arterial pulse has great significance for detecting the early onset of cardiovascular disease and assessing health status, while needs pressure sensors with high sensitivity and signal-to-noise ratio (SNR) to accurately capture more health information concealed in pulse waves. Field effect transistors (FETs) combined with the piezoelectric film is an ultrahigh sensitive pressure sensor category, especially when the FET works in the subthreshold regime, where the signal enhancement effect on the piezoelectric response is the most effective. However, controlling the work regime of FET needs extra external bias assistance which will interfere with the piezoelectric response signal and complicate the test system thus making the scheme difficult to implement. Here, we described a gate dielectric modulation strategy to match the subthreshold region of the FET with the piezoelectric output voltage without external gate bias, finally enhancing the sensitivity of the pressure sensor. A carbon nanotube field effect transistor and polyvinylidene fluoride (PVDF) together form the pressure sensor with a high sensitivity of 7 × 10-1kPa-1for a pressure range of 0.038-0.467 kPa and 6.86 × 10-2kPa-1for a pressure range of 0.467-15.5 kPa, SNR, and the ability to continuously monitor pulse in real-time. Additionally, the sensor enables high-resolution detection of weak pulse signals under large static pressure.

Point-of-Care Ultrasound for Pulse Checks in Pediatric Cardiac Arrest: Two Illustrative Cases.

ABSTRACT: Cardiac arrest is an infrequent but high-stakes scenario in pediatrics. Manual central pulse checks are unreliable. Point-of-care ultrasound is a noninvasive technique to visualize the heart and central vessels during resuscitation. We describe 2 cases in which point-of-care ultrasound helped aid management decisions in pediatric cardiac arrest.

Intelligent Wearable Wrist Pulse Detection System Based on Piezoelectric Sensor Array.

The human radial artery pulse carries a rich array of biomedical information. Accurate detection of pulse signal waveform and the identification of the corresponding pulse condition are helpful in understanding the health status of the human body. In the process of pulse detection, there are some problems, such as inaccurate location of radial artery key points, poor signal noise reduction effect and low accuracy of pulse recognition. In this system, the pulse signal waveform is collected by the main control circuit and the new piezoelectric sensor array combined with the wearable wristband, creating the hardware circuit. The key points of radial artery are located by an adaptive pulse finding algorithm. The pulse signal is denoised by wavelet transform, iterative sliding window and prediction reconstruction algorithm. The slippery pulse and the normal pulse are recognized by feature extraction and classification algorithm, so as to analyze the health status of the human body. The system has accurate pulse positioning, good noise reduction effect, and the accuracy of intelligent analysis is up to 98.4%, which can meet the needs of family health care.

THE OUTCOME OF PULSELESS PINK HAND FOLLOWING CLOSED SUPRACONDYLAR FRACTURE HUMERUS IN PEDIATRICS.

Management of children with supracondylar humeral fractures with pulseless pink hands is still controversial, whether to choose operative or conservative treatment. Proponents of conventional treatment mentioned that most patients can restore the motor and sensory function of the hand shortly after the injury without the need to restore distal pulse by surgery. Opponents of this treatment strategy claim that many patients will develop limb shortening a few years after the injury leading to functional and psychological problems. In this study, we made a comparison of the outcomes of each treatment to help in making policy for the treatment of such types of injuries in our center. This study answers the question "Which method is preferred for treating supracondylar humeral fracture with suspected vascular injury represented by pulseless pink hand, and what are the short and long-term outcomes of each treatment method. The main objective of the study is to settle a policy for the treatment of such types of injuries in our center. This study is a retrospective for the 10-year period from 2010 to 2020, it included 74 patients with blunt trauma to one upper extremity. All patients were children aged one year to fourteen years. Patients with penetrating trauma, combined penetrating and blunt trauma, victims of burns and explosions, and patients with other co-morbidities were excluded. We have two treatment strategies: Conservative (watchful waiting) and Operative exploration. We compared the outcomes of these two strategies regarding the short-term outcome (6 months follow-up) and the long-term outcome (5 years follow-up). We looked for acute and chronic limb ischemia and chronic pain syndrome as the short-term follow-up, while we took limb shortening and chronic limb ischemia and limb function as variables of the long-term follow-up. We don't have the ability to control patients for the psychological examination by a psychiatrist, therefore; we excluded this variable from our study.

A Modern Day Timeline for In-Hospital Monitoring in Perfused, Pulseless Pediatric Supracondylar Humerus Fractures.

BACKGROUND: The perfused, pulseless supracondylar humerus fracture (ppSCHF) remains a consistent topic of discussion in the literature. Inpatient observation of these patients postoperatively for worsening vascular exam or compartment syndrome is frequently recommended but not well studied. The purpose of this study was to evaluate the postoperative complications in a cohort of ppSCHF patients and their timeline to discharge. METHODS: This study is a retrospective review of a prospectively maintained database of all operatively treated supracondylar humerus fractures from a tertiary pediatric hospital from 2013 to 2019. All patients without a palpable pulse were included. We excluded patients with <4 weeks follow-up. Demographic, operative, and postoperative data were collected, including time from presentation to operating room (OR), time from OR to discharge, and incidence of postoperative complications, including return to OR, compartment syndrome, new neurovascular deficits, and Volkmann contractures. The descriptive statistics were used to summarize the data. RESULTS: Among 1371 operatively treated supracondylar humerus fractures, 39 (2.8%) presented with a ppSCHF. Five (15%) had a signal on doppler ultrasound, whereas 34 (85%) had no signal. Thirty-seven (95%) patients had a Gartland type III fracture and 2 (5%) had type IV fractures. Twenty-two (56%) patients had a neurological deficit, of which 14 had an anterior interosseous nerve deficit. The average time to OR was 6.9 (range 2.2 to 15) hours; 6 (15%) required open reduction. At the time of discharge, 85% of patients had a palpable pulse and 13% had a dopplerable signal. Postoperatively, no patients were returned to the OR for any secondary procedures. The average length of stay after the operation was 25 (range 8.5 to 40) hours, with 92% of patients being discharged by 36 hours postoperatively. No patients developed compartment syndrome, new neurological deficits, or Volkmann contractures at a mean follow-up of 112 (range 34 to 310) days. CONCLUSIONS: In our study of 39 patients presenting with ppSCHF, no patient required an unexpected return to the OR, or developed post-treatment compartment syndrome, neurological deficits, or Volkmann contractures. The average time from OR to discharge for ppSCHF was 25 hours. LEVEL OF EVIDENCE: Level II.

A Flexible Pressure Sensor with a Mesh Structure Formed by Lost Hair for Human Epidermal Pulse Wave Monitoring.

Flexible pressure sensors with the capability of monitoring human vital signs show broad application prospects in personalized healthcare. In this work, a hair-based flexible pressure sensor (HBPS) consisting of lost hair and polymer films was proposed for the continuous monitoring of the human epidermal arterial pulse waveform. A macroscale mesh structure formed by lost hair provides a simplified spacer that endows the triboelectric-based flexible pressure sensor with sufficient contact-separation space. Based on this mesh structure design, the hair-based flexible pressure sensor can respond to the slight pressure change caused by an object with 5 mg weight and hold a stable output voltage under 1-30 Hz external pressure excitation. Additionally, the hair-based flexible pressure sensor showed great sensitivity (0.9 V/kPa) and decent stability after 4500 cycles of operation. Given these compelling features, the HBPS can successfully measure the human epidermal arterial pulses with obvious details at different arteries. The proposed HBPS can also be used to monitor the pulse signals of different subjects. Furthermore, the three different pulse wave transmission time (PTT) values (PTT-foot, PTT-middle, and PTT-peak) can be obtained by simultaneously monitoring human pulse and electrocardiogram signals, which has enormous application potential for assessing cardiovascular system health.

Coronary artery disease and its impact on the pulsatile brain: A functional NIRS study.

Recent studies have reported that optical indices of cerebral pulsatility are associated with cerebrovascular health in older adults. Such indices, including cerebral pulse amplitude and the pulse relaxation function (PRF), have been previously applied to quantify global and regional cerebral pulsatility. The aim of the present study was to determine whether these indices are modulated by cardiovascular status and whether they differ between individuals with low or high cardiovascular risk factors (LCVRF and HCVRF) and coronary artery disease (CAD). A total of 60 older adults aged 57-79 were enrolled in the study. Participants were grouped as LCVRF, HCVRF, and CAD. Participants were asked to walk freely on a gym track while a near-infrared spectroscopy (NIRS) device recorded hemodynamics data. Low-intensity, short-duration walking was used to test whether a brief cardiovascular challenge could increase the difference of pulsatility indices with respect to cardiovascular status. Results indicated that CAD individuals have higher global cerebral pulse amplitude compared with the other groups. Walking reduced global cerebral pulse amplitude and PRF in all groups but did not increase the difference across the groups. Instead, walking extended the spatial distribution of cerebral pulse amplitude to the anterior prefrontal cortex when CAD was compared to the CVRF groups. Further research is needed to determine whether cerebral pulse amplitude extracted from data acquired with NIRS, which is a noninvasive, inexpensive method, can provide an index to characterize the cerebrovascular status associated with CAD.

Evaluating the Sensitivity of Resting-State BOLD Variability to Age and Cognition after Controlling for Motion and Cardiovascular Influences: A Network-Based Approach.

Recent functional magnetic resonance imaging (fMRI) studies report that moment-to-moment variability in the BOLD signal is related to differences in age and cognition and, thus, may be sensitive to age-dependent decline. However, head motion and/or cardiovascular health (CVH) may contaminate these relationships. We evaluated relationships between resting-state BOLD variability, age, and cognition, after characterizing and controlling for motion-related and cardiovascular influences, including pulse, blood pressure, BMI, and white matter hyperintensities (WMH), in a large (N = 422) resting-state fMRI sample of cognitively normal individuals (age 43-89). We found that resting-state BOLD variability was negatively related to age and positively related to cognition after maximally controlling for head motion. Age relationships also survived correction for CVH, but were greatly reduced when correcting for WMH alone. Our results suggest that network-based machine learning analyses of resting-state BOLD variability might yield reliable, sensitive measures to characterize age-related decline across a broad range of networks. Age-related differences in resting-state BOLD variability may be largely sensitive to processes related to WMH burden.

Respiratory, cardiac and metabolic responses during electrical muscle stimulation in quadriceps muscle versus comparable voluntary muscle contractions.

Electrical Muscle Stimulation (EMS) and voluntary muscle contraction (VMC) are both acceptable rehabilitative modalities to preserve muscle strength loss. The study aimed to compare respiratory, metabolic, and cardiac parameters during quadriceps muscle contraction (QMC) using either EMS or VMC with comparable generated low intensity muscle force. Thirty healthy non-smoker males, age 20-58 years with normal BMI and low to moderate physical activity, underwent two 20-min sessions of comparable QMC using EMS vs VMC at the same day. The BIODEX III isokinetic dynamometer was used to assess maximum isometric force and the comparable force generated during each condition (EMS vs VMC), while the METAMAX 3B portable metabolic system was used to measure continuously the physiological parameters. Tolerable EMS was used (mean: 33 ± 1.5 mA, at 75 Hz). Each contraction lasted 10 sec followed by 20 sec rest. Paired t-tests were used for comparisons between sessions. A relatively low proportion of maximum isometric force (EMS: 8.5% vs VMC: 8.6%) and torque (EMS: 16 ± 1.3 vs VMC: 16 ± 1.1 Nm) were generated during each session. Mean minute ventilation (EMS: 10.8 L vs VMC: 9.8 L), tidal volume (EMS: 0.6 L vs VMC: 0.5 L), O2 uptake (EMS: 0.31 L/min vs VMC: 0.26 L/min) and O2 pulse (EMS: 3.9 ml/beat vs VMC: 3.6 ml/beat) were different between sessions (p ≤ .05); while heart rate (EMS: 72 beats/min vs VMC: 71 beats/min) was equal. Quadriceps muscle EMS induces higher respiratory and metabolic responses compared to equal magnitude VMC in healthy males.

Checking the pulse in the 21st century: Interobserver reliability of carotid pulse detection by point-of-care ultrasound.

INTRODUCTION: Detection of a pulse is crucial to decision-making in the care of patients who are in cardiac arrest, however, the current standard of manual pulse palpation is unreliable. An emerging alternative is the use of point-of-care ultrasound (POCUS) for direct assessment of the carotid pulse. The primary objective of this study is to determine the interobserver reliability for physician interpretation of pre-recorded point-of-care ultrasound pulse-check clips for patients who are in cardiac arrest. METHODS: We conducted a web-based survey of residents and physicians working in an academic center. Participants were shown a tutorial demonstrating POCUS detection of the carotid pulse and then asked to interpret 15 carotid pulse ultrasound clips from patients who were in cardiac arrest. The primary outcome was interobserver reliability for carotid pulse assessment. Secondary outcomes included interobserver reliability stratified by physician role and POCUS experience, median tutorial and median pulse assessment duration. Interobserver reliability was determined by Krippendorff's ⍺. RESULTS: 68 participants completed the study, with a response rate of 75%. There was high interobserver reliability for pulse assessment amongst all study participants (⍺ = 0.874, 95% CI 0.869 to 0.879). All sub-groups had ⍺ greater than 0.8. Median tutorial duration was 35 s (IQR 29). Median pulse assessment duration was 6 s (IQR 5) with 76% of assessments completed within 10 s. CONCLUSION: Interpretation of the carotid pulse by POCUS showed high interobserver reliability. Further work must be done to determine the performance of POCUS pulse assessment in real-time for patients who are in cardiac arrest.

Treatment of pediatric supracondylar humerus fractures accompanied with pink pulseless hands.

BACKGROUND: The optimal treatment for pediatric supracondylar humeral fractures accompanied with a pink pulseless hand is controversial. Some clinicians recommend close observation after closed reduction and percutaneous pinning of the fractures, while some recommend surgical exploration if the radial pulse is unpalpable. The present study aimed to analyze the benefits and outcomes of close observation for treating pediatric supracondylar humeral fractures with a pink pulseless hand. METHODS: Thirteen consecutive children presenting with a pink pulseless hand following supracondylar humeral fracture were enrolled in this study. Preoperative and postoperative color-flow Duplex ultrasound detection was used to assess brachial artery compromise in most cases. Urgent closed reduction and percutaneous pinning of the fractures were attempted first. Close observation was carried out when the hand was pink and pulseless with an absent radial pulse. RESULTS: Preoperative color-flow Duplex ultrasound showed no disruption of the brachial artery in cases detected. Compression of the artery by the proximal fragment was observed in most cases, with one case of entrapment of the artery between fragments, and thrombus considered in two cases. All cases underwent urgent surgery, after which nine experienced immediate return of the radial pulse. The remaining four without a palpable pulse were managed with close observation and no deterioration of the vascular status was observed; therefore, no surgical exploration was performed. Postoperative color-flow Duplex ultrasound revealed continuity of the artery and rich collateral circulation. Patients completed an average of 4.5 years of follow-up, during which no major complications occurred. All patients achieved excellent limb function. CONCLUSIONS: Our study demonstrates that close observation after urgent closed reduction and percutaneous pinning is a sufficient approach for the treatment of pediatric supracondylar humeral fractures accompanied with a pink pulseless hand. Surgical exploration is not necessary as long as the hand is warm and well perfused. Color-flow Duplex ultrasound is beneficial for assessing vascular compromise and determining treatment strategies.

Femoral Artery Thrombosis After Pediatric Cardiac Catheterization.

Femoral artery thrombosis (FAT) is an adverse event post-catheterization. We decided to study the incidence and risk factors of FAT before and after initiation of a pulse loss monitoring program. All cardiac catheterization cases performed using femoral arterial vascular access were retrospectively reviewed. The study period was divided into two eras: before (era 1), and after the initiation of the protocol (era 2). The primary outcome was FAT requiring therapy. Univariable and multivariable logistic regression models were used to identify factors associated with FAT. Receiver operating characteristic curve were generated to predict FAT. Our cohort consisted of 2,388 cases including 467 (19.6%) infants weighing < 10 kg. The overall incidence of FAT was 1.7% (n = 41). The incidence of FAT was 3.5 times higher in era 2 (p < 0.001). Multivariable model showed that era, weight, sheath exchange, and coarctation intervention were significantly associated with FAT. Infants younger than 7.7 months and less than 6.7 kg were found to be at highest risk for FAT. Our study shows that the incidence of FAT may be underestimated without a monitoring program. Small infants and coarctation interventions requiring larger sheaths or sheath exchanges are at highest risk for FAT.

Pulse Rate Variability Analysis Using Remote Photoplethysmography Signals.

Pulse rate variability (PRV) refers to the change in the interval between pulses in the blood volume pulse (BVP) signal acquired using photoplethysmography (PPG). PRV is an indicator of the health status of an individual's autonomic nervous system. A representative method for measuring BVP is contact PPG (CPPG). CPPG may cause discomfort to a user, because the sensor is attached to the finger for measurements. In contrast, noncontact remote PPG (RPPG) extracts BVP signals from face data using a camera without the need for a sensor. However, because the existing RPPG is a technology that extracts a single pulse rate rather than a continuous BVP signal, it is difficult to extract additional health status indicators. Therefore, in this study, PRV analysis is performed using lab-based RPPG technology that can yield continuous BVP signals. In addition, we intended to confirm that the analysis of PRV via RPPG can be performed with the same quality as analysis via CPPG. The experimental results confirmed that the temporal and frequency parameters of PRV extracted from RPPG and CPPG were similar. In terms of correlation, the PRVs of RPPG and CPPG yielded correlation coefficients between 0.98 and 1.0.

Portable Interactive Pulse Tactile Recorder and Player System.

Pulse palpation is an effective method for diagnosing arterial diseases. However, most pulse measurement devices use preconfigured pressures to collect pulse signals, and most pulse tactile simulators can only display standard or predefined pulse waveforms. Here, a portable interactive human pulse measurement and reproduction system was developed that allows users to take arbitrary pulses and experience realistic simulated pulse tactile feedback in real time by using their natural pulse-taking behaviors. The system includes a pulse tactile recorder and a pulse tactile player. Pulse palpation forces and vibrations can be recorded and realistically replayed for later tactile exploration and examination. To retain subtle but vital pulse information, empirical mode decomposition was used to decompose pulse waveforms into several intrinsic mode functions. Artificial neural networks were then trained based on intrinsic mode functions to determine the relationship between the driving signals of the pulse tactile player and the resulting vibration waveforms. Experimental results indicate that the average normalized root mean square error and the average R-squared values between the reproduced and original pulses were 0.0654 and 0.958 respectively, which indicate that the system can reproduce high-fidelity pulse tactile vibrations.

A Transfer Function Model Development for Reconstructing Radial Pulse Pressure Waveforms Using Non-Invasively Measured Pulses by a Robotic Tonometry System.

The primary goal of this study is to develop a mathematical model that can establish a transfer function relationship between the "external" pulse pressures measured by a tonometer and the "internal" pulse pressure in the artery. The purpose of the model is to accurately estimate and rebuild the internal pulse pressure waveforms using arterial tonometry measurements. To develop and validate a model without human subjects and operators for consistency, this study employs a radial pulse generation system, a robotic tonometry system, and a write model with an artificial skin and vessel. A transfer function model is developed using the results of the pulse testing and the mechanical characterization testing of the skin and vessel. To evaluate the model, the pulse waveforms are first reconstructed for various reference pulses using the model with tonometry data. They are then compared with pulse waveforms acquired by internal measurement (by the built-in pressure sensor in the vessel) the external measurement (the on-skin measurement by the robotic tonometry system). The results show that the model-produced pulse waveforms coinciding well with the internal pulse waveforms with small relative errors, indicating the effectiveness of the model in reproducing the actual pulse pressures inside the vessel.

Bio-Impedance Measurement Optimization for High-Resolution Carotid Pulse Sensing.

Continuous hemodynamic monitoring is important for long-term cardiovascular healthcare, especially in hypertension. The impedance plethysmography (IPG) based carotid pulse sensing is a non-invasive diagnosis technique for measuring pulse signals and further evaluating the arterial conditions of the patient such as continuous blood pressure (BP) monitoring. To reach the high-resolution IPG-based carotid pulse detection for cardiovascular applications, this study provides an optimized measurement parameter in response to obvious pulsation from the carotid artery. The influence of the frequency of excitation current, electrode cross-sectional area, electrode arrangements, and physiological site of carotid arteries on IPG measurement resolution was thoroughly investigated for optimized parameters. In this study, the IPG system was implemented and installed on the subject's neck above the carotid artery to evaluate the measurement parameters. The measurement results within 6 subjects obtained the arterial impedance variation of 2137 mΩ using the optimized measurement conditions, including excitation frequency of 50 kHz, a smaller area of 2 cm2, electrode spacing of 4 cm and 1.7 cm for excitation and sensing functions, and location on the left side of the neck. The significance of this study demonstrates an optimized measurement methodology of IPG-based carotid pulse sensing that greatly improves the measurement quality in cardiovascular monitoring.

[Full-information Force Sensor for Pulse Condition Diagnose].

According to the collection principles and characteristics of the pulse physiological signals of traditional Chinese medicine, combined with the international standard requirements of the pulse graph force transducer (ISO 19614:2017-05), a special force sensor component that can be used for a complete and objective collection of pulse signals has been developed, this sensor meets the requirements of industrialization. The sensor can measure the pulse amplitude and width signals of the cunpart of the human body. In addition, three sensors can be placed at the cun, guan, chi part at the same time, so that the "three body parts and nine pulse-taking sites" can be realized synchronously. After the sensor has been verified, the results meet the relevant requirements of international standard. The consistency of the result can be reached to 92.3% compared with the diagnosis result of clinical TCM experts.

Pulselessness After Initiation of Cardiopulmonary Resuscitation for Bradycardia in Hospitalized Children.

BACKGROUND: Cardiopulmonary resuscitation (CPR) is initiated in hospitalized children with bradycardia and poor perfusion. However, their rate of progression to pulseless cardiac arrest despite CPR and the differences in survival compared with initially pulseless arrest are unknown. We examined the prevalence and predictors of survival of children who progress from bradycardia to pulseless in-hospital cardiac arrest despite CPR. METHODS: Pediatric patients >30 days and <18 years of age who received CPR at hospitals participating in Get With The Guidelines-Resuscitation during 2000 to 2016 were included. Each CPR event was classified as bradycardia with pulse, bradycardia with subsequent pulselessness, and initial pulseless cardiac arrest. We assessed risk-adjusted rates of survival to hospital discharge using multilevel Poisson regression models. RESULTS: Overall, 5592 pediatric patients were treated with CPR, of whom 2799 (50.1%) received CPR for bradycardia with poor perfusion and 2793 (49.9%) for initial pulseless cardiac arrest. Among those with bradycardia, 869 (31.0%, or 15.5% of cohort) became pulseless after a median of 3 minutes of CPR (interquartile range, 1-9 minutes). Rates of survival to discharge were 70.0% (1351 of 1930) for bradycardia with pulse, 30.1% (262 of 869) for bradycardia progressing to pulselessness, and 37.5% (1046 of 2793) for initial pulseless cardiac arrest (P for difference across groups <0.001). Children who became pulseless despite CPR for bradycardia had a 19% lower likelihood (risk ratio, 0.81 [95% CI, 0.70, 0.93]; P=0.004) of surviving to hospital discharge than those who were initially pulseless. Among children who progressed to pulselessness despite CPR for bradycardia, a longer interval between CPR and pulselessness was a predictor of lower survival (reference, <2 minutes; for 2-5 minutes, risk ratio, 0.54 [95% CI, 0.41-0.70]; for >5 minutes, risk ratio, 0.41 [95% CI, 0.32-0.53]). CONCLUSIONS: Among hospitalized children in whom CPR is initiated, half have bradycardia with poor perfusion at the initiation of chest compressions, and nearly one-third of these progress to pulseless in-hospital cardiac arrest despite CPR. Survival was significantly lower for children who progress to pulselessness despite CPR compared with those who were initially pulseless. These findings suggest that pediatric patients who lose their pulse despite resuscitation attempts are at particularly high risk and require a renewed focus on postresuscitation care.