Chest diameter measurement in pediatric patients for chest compression feedback calibration

Adequate compression depth is a main quality parameter during cardiopulmonary resuscitation (CPR). Current CPR feedback devices can guide adult target depth which is fixed between 5 and 6 cm. For pediatric patients, conversely, target depth should be one third of the antero-posterior diameter of the chest. The aim of this study was to develop an algorithm to estimate chest diameter in pediatric patients using accelerometers. Using a tri-axial accelerometer, we measured the accelerations generated when moving the sensor from the floor to five different heights that simulated chest diameter. Five volunteers generated two records each per height. A total of fifty records were acquired. Chest diameter was measured by discrete integration of the z-axis acceleration signal. Velocity signal was band-pass filtered before computing the displacement signal. Chest diameter was identified as the displacement value at the instant in which the movement finished. Median (P25, P75) unsigned absolute and relative errors were 0.9 cm (0.3, 1.9) and 9.2 % (2.5, 14.6), respectively. Error in estimation of pediatric target compression depth was below 6.5 mm in 75 % of the cases. The proposed algorithm could be used to calibrate target chest compression depth in CPR feedback devices to be adapted for pediatric patients

Rhythm analysis during cardiopulmonary resuscitation: past, present, and future

Copyright © 2014 Sofia Ruiz de Gauna et al. This is an open access article originally published in BioMed Research International, distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Survival from out-of-hospital cardiac arrest depends largely on two factors: early cardiopulmonary resuscitation (CPR) and early defibrillation. CPRmust be interrupted for a reliable automated rhythmanalysis because chest compressions induce artifacts in the ECG. Unfortunately, interrupting CPR adversely affects survival. In the last twenty years, research has been focused on designing methods for analysis of ECG during chest compressions. Most approaches are based either on adaptive filters to remove the CPR artifact or on robust algorithms which directly diagnose the corrupted ECG. In general, all themethods report low specificity values when tested on short ECG segments, but how to evaluate the real impact on CPR delivery of continuous rhythm analysis during CPR is still unknown. Recently, researchers have proposed a new methodology to measure this impact. Moreover, new strategies for fast rhythm analysis during ventilation pauses or high-specificity algorithms have been reported. Our objective is to present a thorough review of the field as the starting point for these late developments and to underline the open questions and future lines of research to be explored in the following years

Filtering the Cardiopulmonary Resuscitation Artifact: Influence of the Signal-to-Noise-Ratio on the Accuracy of the Shock Advice Algorithm

Abstract A reliable diagnosis by automated external defibrillators (AED) during cardiopulmonary resuscitation (CPR) would reduce hands-off time, thus increasing the resuscitation success. Several filtering techniques have been proposed to remove the artifact induced on the ECG by chest compressions. The improvement in the signal-to-noise ratio (SNR) has been widely used to test the performance of the filter, using artificial mixtures of ECG signals and CPR artifacts. In this work, we analyzed the influence of the SNR, estimated from corrupted out-of-hospital cardiac arrest episodes, on the AED diagnostic accuracy before and after artifact removal. Filtering improved the sensitivity for records with low SNR, however the specificity was largely independent of the SNR. Moreover, the total specificity decreased after filtering due to misclassified asystole records

Rhythm analysis during cardiopulmonary resuscitation: past, present

Survival from out-of-hospital cardiac arrest depends largely on two factors: early cardiopulmonary resuscitation (CPR) and early defibrillation. CPR must be interrupted for a reliable automated rhythm analysis because chest compressions induce artifacts in the ECG. Unfortunately, interrupting CPR adversely affects survival. In the last twenty years, research has been focused on designing methods for analysis of ECG during chest compressions. Most approaches are based either on adaptive filters to remove the CPR artifact or on robust algorithms which directly diagnose the corrupted ECG. In general, all the methods report low specificity values when tested on short ECG segments, but how to evaluate the real impact on CPR delivery of continuous rhythm analysis during CPR is still unknown. Recently, researchers have proposed a new methodology to measure this impact. Moreover, new strategies for fast rhythm analysis during ventilation pauses or high-specificity algorithms have been reported. Our objective is to present a thorough review of the field as the starting point for these late developments and to underline the open questions and future lines of research to be explored in the following years

Chest Diameter Measurement in Pediatric Patients for Chest Compression Feedback Calibration

Adequate compression depth is a main quality parameter during cardiopulmonary resuscitation (CPR). Current CPR feedback devices can guide adult target depth which is fixed between 5 and 6 cm. For pediatric patients, conversely, target depth should be one third of the antero-posterior diameter of the chest. The aim of this study was to develop an algorithm to estimate chest diameter in pediatric patients using accelerometers. Using a tri-axial accelerometer, we measured the accelerations generated when moving the sensor from the floor to five different heights that simulated chest diameter. Five volunteers generated two records each per height. A total of fifty records were acquired. Chest diameter was measured by discrete integration of the z-axis acceleration signal. Velocity signal was band-pass filtered before computing the displacement signal. Chest diameter was identified as the displacement value at the instant in which the movement finished. Median (P25, P75) unsigned absolute and relative errors were 0.9 cm (0.3, 1.9) and 9.2 % (2.5, 14.6), respectively. Error in estimation of pediatric target compression depth was below 6.5 mm in 75 % of the cases. The proposed algorithm could be used to calibrate target chest compression depth in CPR feedback devices to be adapted for pediatric patients

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care