Airway and ventilation management during cardiopulmonary resuscitation and after successful resuscitation

Explorative study on lower inflection point dynamics during cardiopulmonary resuscitation: Potential implications for airway management

INTRODUCTION

In patients undergoing cardiopulmonary resuscitation (CPR) after an Out-of-Hospital Cardiac Arrest (OHCA), intrathoracic airway closure can impede ventilation, adversely affecting patient outcomes. This explorative study investigates the evolution of intrathoracic airway closure by analyzing the lower inflection point (LIP) during the inspiration phase of CPR, aiming to identify the potential thresholds for alveolar recruitment.

METHODS AND MATERIALS

Eleven OHCA patients undergoing CPR with endotracheal intubation and manual bag ventilation were included. Flow and pressure measurements were obtained using Sensirion SFM3200AW and Wika CPT2500 sensors attached to the endotracheal tube, connected to a Surface Go Tablet for data collection. Flow data was analyzed in Microsoft Excel, while pressure data was processed using the Wika USBsoft2500 application. Analysis focused on the inspiration phase of the first 6-8 breaths, with an additional 2 breaths recorded and analyzed at the end of CPR.

RESULTS

Across the cohort, the median tidal volume was 870.00 milliliter (mL), average flow was 31.90 standard liters per minute (slm), and average pressure was 17.21 cmH2O. The calculated average LIP was 31.47 cmH2O. Most cases (72.7%) exhibited a negative trajectory in LIP evolution during CPR, with 2 cases (18.2%) showing a positive trajectory and 1 case remaining inconclusive. The average LIP in the first 8 breaths was significantly higher than in the last 2 breaths (p = 0.018). No significant correlation was found between average LIP and return of spontaneous circulation (ROSC), compression depth, frequency, or end-tidal CO2 (EtCO2). However, a significant negative correlation was observed between the average LIP of the last 2 breaths and CPR duration (p = 0.023).

VALIDATION

LIP calculation in low-flow ventilations using the novel mathematical method yielded values consistent with those reported in the literature.

DISCUSSION/CONCLUSION

These explorative data demonstrate a predominantly negative trajectory in LIP evolution during CPR, suggesting potential challenges in maintaining airway patency. Limitations include a small sample size and sensor recording issues. Further research is warranted to explore the evolution of LIP and its implications for personalized ventilation strategies in CPR.

Machine Learning Identifies Higher Survival Profile In Extracorporeal Cardiopulmonary Resuscitation

OBJECTIVES

Extracorporeal cardiopulmonary resuscitation (ECPR) has been shown to improve neurologically favorable survival in patients with refractory out-of-hospital cardiac arrest (OHCA) caused by shockable rhythms. Further refinement of patient selection is needed to focus this resource-intensive therapy on those patients likely to benefit. This study sought to create a selection model using machine learning (ML) tools for refractory cardiac arrest patients undergoing ECPR.

DESIGN

Retrospective cohort study.

SETTING

Cardiac ICU in a Quaternary Care Center.

PATIENTS

Adults 18-75 years old with refractory OHCA caused by a shockable rhythm.

METHODS

Three hundred seventy-six consecutive patients with refractory OHCA and a shockable presenting rhythm were analyzed, of which 301 underwent ECPR and cannulation for venoarterial extracorporeal membrane oxygenation. Clinical variables that were widely available at the time of cannulation were analyzed and ranked on their ability to predict neurologically favorable survival.

INTERVENTIONS

ML was used to train supervised models and predict favorable neurologic outcomes of ECPR. The best-performing models were internally validated using a holdout test set.

MEASUREMENTS AND MAIN RESULTS

Neurologically favorable survival occurred in 119 of 301 patients (40%) receiving ECPR. Rhythm at the time of cannulation, intermittent or sustained return of spontaneous circulation, arrest to extracorporeal membrane oxygenation perfusion time, and lactic acid levels were the most predictive of the 11 variables analyzed. All variables were integrated into a training model that yielded an in-sample area under the receiver-operating characteristic curve (AUC) of 0.89 and a misclassification rate of 0.19. Out-of-sample validation of the model yielded an AUC of 0.80 and a misclassification rate of 0.23, demonstrating acceptable prediction ability.

CONCLUSIONS

ML can develop a tiered risk model to guide ECPR patient selection with tailored arrest profiles.

The early change in pH values after out-of-hospital cardiac arrest is not associated with neurological outcome at hospital discharge

Background

The association between pH values and outcome for patients after out-of-hospital cardiac arrest (OHCA) was not fully elucidated; besides, the relationship of change in pH values and neurological outcome was unknown. The aim was to explore the association of pH values as well as change in pH values and neurological outcome for OHCA cardiac patients.

Methods

The adult patients with non-traumatic out-of-hospital cardiac arrest, shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, and at least two arterial blood gases analysis recorded after admission were included. The change in pH values is calculated as the difference between the second and first pH value, and divided by time interval got the rate of change in pH values. The primary outcome was modified Rankin Score (mRS), dichotomized to good (mRS 0-3) and poor (mRS 4-6) outcomes at hospital discharge. The independent relationship of the first pH value, second pH value, and changes in pH values with neurological outcome was investigated with multivariable logistic regression models, respectively.

Results

A total of 1388 adult patients were included for analysis, of which 514 (37%) had good neurological outcome. The median first pH value and second pH value after admission were 7.21 (interquartile range [IQR] 7.09-7.29) and 7.28 (IQR 7.20-7.36), respectively. The median absolute, relative change, and rate of changes in pH values were 0.08 (IQR 0.01-0.16), 1.10% (IQR 0.11-2.22%), and 0.02 (IQR 0-0.06) per hour, respectively. After adjusting for confounders, the higher first pH value (odds ratio [OR] 3.81, confidence interval [CI] 1.60-9.24, P = 0.003) and higher second pH value (OR 9.54, CI 3.45-26.87, P < 0.001) after admission were associated with good neurological outcome, respectively. The absolute (OR 1.58, CI 0.58-4.30, P = 0.368) and relative (OR 1.03, CI 0.96-1.11, P = 0.399) change as well as the rate of change (OR 0.98, CI 0.33-2.71, P = 974) in pH values were not associated with neurological outcome.

Conclusions

For OHCA patients, abnormality in pH values was very common, with a more acidic pH value indicating poor neurological outcome. However, the change in pH values was not associated with outcomes.

Is the occurrence of reversed airflow in manual ventilation during cardiopulmonary resuscitation associated with reduced net tidal volumes?

Background

During cardiopulmonary resuscitation, following advanced airway placement, chest compressions and ventilations are performed simultaneously. During inspiration, chest compressions and positive pressure ventilation exert opposite forces on the respiratory system, frequently resulting in reversed airflow.

Methods

Following endotracheal intubation, a flow sensor was connected to the respiratory circuit of intubated, adult out-of-hospital cardiac arrest patients receiving manual chest compressions and manual ventilations. Chest compression parameters were measured using an accelerometer. Inspiratory and expiratory volumes during the inspiratory phase of positive pressure ventilations were quantified. Duration of the inspiratory and expiratory phases was calculated.

Results

In this study, 25 patients were included, 682 ventilations were analyzed. Reversed airflow was observed in 23 patients, occurring 389 times during 270 ventilations. Median volume of reversed airflow was 2 mL (IQR 1.4-7 mL). There was no difference between net tidal volumes of ventilations during which reversed airflow did (median 420 mL, IQR 315-549) or did not occur (median 406 mL, IQR 308-530). When reversed airflow occurred, the duration of the inspiratory phase was longer (median 1.2 sec, IQR 0.9-1.4) compared to ventilations without reversed airflow (median 0.9 sec, IQR 0.9-1.4). Univariate analysis showed a weak correlation between chest compression depth and volume of reversed airflow.

Conclusion

Reversed airflow frequently occurs during cardiopulmonary resuscitation. Volumes of reversed airflow were small, showing a weak correlation with chest compression depth. The occurrence of reversed airflow was not associated with reduced net tidal volumes.

Automatic Mechanical Ventilation vs Manual Bag Ventilation During CPR: A Pilot Randomized Controlled Trial

BACKGROUND

There is insufficient evidence supporting the theory that mechanical ventilation can replace the manual ventilation method during CPR.

RESEARCH QUESTION

Is using automatic mechanical ventilation (MV) feasible and comparable to the manual ventilation method during CPR?

STUDY DESIGN AND METHODS

This pilot randomized controlled trial compared MV and manual bag ventilation (BV) during CPR after out-of-hospital cardiac arrest (OHCA). Patients with medical OHCA arriving at the ED were randomly assigned to two groups: an MV group using a mechanical ventilator and a BV group using a bag valve mask. Primary outcome was any return of spontaneous circulation (ROSC). Secondary outcomes were changes of arterial blood gas analysis results during CPR. Tidal volume, minute volume, and peak airway pressure were also analyzed.

RESULTS

A total of 60 patients were enrolled, and 30 patients were randomly assigned to each group. There were no statistically significant differences in basic characteristics of OHCA patients between the two groups. The rate of any return of spontaneous circulation was 56.7% in the MV group and 43.3% in the BV group, indicating no significant (P = .439) difference between the two groups. There were also no statistically significant differences in changes of PH, Pco2, Po2, bicarbonate, or lactate levels during CPR between the two groups (P values = .798, 0.249, .515, .876, and .878, respectively). Significantly lower tidal volume (P < .001) and minute volume (P = .009) were observed in the MV group.

INTERPRETATION

In this pilot trial, the use of MV instead of BV during CPR was feasible and could serve as a viable alternative. A multicenter randomized controlled trial is needed to create sufficient evidence for ventilation guidelines during CPR.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT05550454; URL: www.

CLINICALTRIALS

gov.

Implementation and use of a supraglottic airway device in the management of out-of-hospital cardiac arrest by firefighter first responders - A prospective feasibility study

Aim

We wanted to assess the implementation and use of a supraglottic airway (SGA) for on-call firefighter first responders in out-of-hospital cardiac arrest.

Methods

We trained 502 firefighter first responders, located at 35 fire stations in the South-East of Norway, in the use of SGA during cardiopulmonary resuscitation in adult out-of-hospital cardiac arrest. Training consisted of 45 minutes of theoretical and practical training in small groups.Primary outcome was successful ventilation with SGA assessed by both firefighter first responders and first paramedic arriving on-scene. Secondary outcomes included time expenditure and complications related to the procedure, evaluation of the training, and descriptive characteristics of the out-of-hospital cardiac arrest cases.

Results

An SGA was used by firefighter first responders in 23 out-of-hospital cardiac arrests, and successful ventilation was achieved in 20 (87%) cases. Air-leak was described in the three unsuccessful cases. The median procedural time was 30 seconds (IQR = 15-40), with no observed procedural complications. Firefighter first responders arrived in median time 9 minutes (IQR = 6-10 min) before the ambulance. They performed chest compressions on all patients and 6 (26%) of the patients received shock with semi-automatic external defibrillator. After training, all participants were able to successfully ventilate a manikin with the SGA. The cost of the SGA equipment for all fire stations was 3955 GBP.

Conclusion

Implementation of an SGA for firefighter first responders in out-of-hospital cardiac arrest management seems feasible, safe and can be introduced with limited amount of training and limited use of resources.

Ventilatory improvement with mechanical ventilator versus bag in non-traumatic out-of-hospital cardiac arrest: SYMEVECA study, phase 1

AIM

To analyze differences in ventilatory parameters and outcome with different ventilatory methods during CPR.

METHODS

Pragmatic prospective quasi-experimental study in out-of-hospital urban environment. Patients over 18 years of age in non-traumatic cardiac arrest, attended by an emergency medical service between April 2021 and September 2022, were included. Two groups were compared according to the ventilatory method: mechanical ventilator (IPPV, tidal volume 7 ml/kg, frequency 10-12 bpm) or manual resuscitator bag. The main variables of interest are those of gasometry performed 15 minutes after intubation or when spontaneous circulation is recovered and final outcome. Patients were followed up to hospital discharge.

RESULTS

Of the 359 patients attended, 150 were included (71 in IPPV and 79 with a bag). In patients with arterial blood gases, pCO2 was 67.8 ± 21.1 in the IPPV group vs 95.9 ± 39.0 mmHg in the bag group (p = 0.006) and pH was 7.00 ± 0.18 vs 6.92 ± 0.18 (p = 0.18). With a venous sample, the pCO2 was 68.1 ± 18.9 vs 89.5 ± 26.5 mmHg (p < 0.001) and the pH was 7.03 ± 0.15 vs 6.94 ± 0.17 (p = 0.005), respectively. Survival with CPC 1-2 to hospital discharge was 15.6% with IPPV and 11.3% with bag (p = 0.44).

CONCLUSION

The use of a mechanical ventilator in IPPV was associated with a better ventilatory status during CPR compared to the use of the bag, without conclusive data regarding its clinical repercussion with the sample collected.

Cardiopulmonary resuscitation during hyperbaric oxygen therapy: a comprehensive review and recommendations for practice

BACKGROUND

Cardiopulmonary resuscitation (CPR) during hyperbaric oxygen therapy (HBOT) presents unique challenges due to limited access to patients in cardiac arrest (CA) and the distinct physiological conditions present during hyperbaric therapy. Despite these challenges, guidelines specifically addressing CPR during HBOT are lacking. This review aims to consolidate the available evidence and offer recommendations for clinical practice in this context.

MATERIALS AND METHODS

A comprehensive literature search was conducted in PubMed, EMBASE, Cochrane Library, and CINAHL using the search string: "(pressure chamber OR decompression OR hyperbaric) AND (cardiac arrest OR cardiopulmonary resuscitation OR advanced life support OR ALS OR life support OR chest compression OR ventricular fibrillation OR heart arrest OR heart massage OR resuscitation)". Additionally, relevant publications and book chapters not identified through this search were included.

RESULTS

The search yielded 10,223 publications, with 41 deemed relevant to the topic. Among these, 18 articles (primarily case reports) described CPR or defibrillation in 22 patients undergoing HBOT. The remaining 23 articles provided information or recommendations pertaining to CPR during HBOT. Given the unique physiological factors during HBOT, the limitations of current resuscitation guidelines are discussed.

CONCLUSIONS

CPR in the context of HBOT is a rare, yet critical event requiring special considerations. Existing guidelines should be adapted to address these unique circumstances and integrated into regular training for HBOT practitioners. This review serves as a valuable contribution to the literature on "CPR under special circumstances".

Lower versus higher oxygen targets for out-of-hospital cardiac arrest: a systematic review and meta-analysis

BACKGROUND

Supplemental oxygen is commonly administered to patients after out-of-hospital cardiac arrest. However, the findings from studies on oxygen targeting for out-of-hospital cardiac arrest are inconclusive. Thus, we conducted a systematic review and meta-analysis to evaluate the impact of lower oxygen target compared with higher oxygen target on patients after out-of-hospital cardiac arrest.

METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, from inception to February 6, 2023, for randomized controlled trials comparing lower and higher oxygen target in adults (aged ≥ 18 years) after out-of-hospital cardiac arrest. We screened studies and extracted data independently. The primary outcome was mortality at 90 days after cardiac arrest. We assessed quality of evidence using the grading of recommendations assessment, development, and evaluation approach. This study was registered with PROSPERO, number CRD42023409368.

RESULTS

The analysis included 7 randomized controlled trials with a total of 1451 participants. Compared with lower oxygen target, the use of a higher oxygen target was not associated with a higher mortality rate (relative risk 0.97, 95% confidence intervals 0.82 to 1.14; I2 = 25%). Findings were robust to trial sequential, subgroup, and sensitivity analysis.

CONCLUSION

Lower oxygen target did not reduce the mortality compared with higher oxygen target in patients after out-of-hospital cardiac arrest.

Airway Management of the Cardiac Arrest Victim

Appropriate airway management is critical to successful cardiac arrest resuscitation. However, the timing and method of airway management during cardiac arrest have traditionally been guided by expert and consensus opinion informed by observational data. In the last 5 years, recent studies, including several randomized controlled trials (RCTs), have provided additional clarity to help guide airway management. This article will review both current data and guidelines for airway management in cardiac arrest, a stepwise approach to airway management, the utility of various airway adjuncts, and best practices for oxygenation and ventilation in the peri-arrest period.

Use of a Portable Mechanical Ventilator during Cardiopulmonary Resuscitation is Feasible, Improves Respiratory Parameters, and Prevents the Decrease of Dynamic Lung Compliance

BACKGROUND

For practical and protective ventilation during cardiopulmonary resuscitation (CPR), a 150-grams mechanical ventilator (VLP2000E) that limits peak inspiratory pressure (PIP) during simultaneous ventilation with chest compressions was developed.

OBJECTIVES

To evaluate the feasibility of VLP2000E ventilation during CPR and to compare monitored parameters versus bag-valve ventilation.

METHODS

A randomized experimental study with 10 intubated pigs per group. After seven minutes of ventricular fibrillation, 2-minute CPR cycles were delivered. All animals were placed on VLP2000E after achieving return of spontaneous circulation (ROSC).

RESULTS

Bag-valve and VLP2000E groups had similar ROSC rate (60% vs. 50%, respectively) and arterial oxygen saturation in most CPR cycles, different baseline tidal volume [0.764 (0.068) vs. 0.591 (0.123) L, p = 0.0309, respectively] and, in 14 cycles, different PIP [52 (9) vs. 39 (5) cm H2O, respectively], tidal volume [0.635 (0.172) vs. 0.306 (0.129) L], ETCO2[14 (8) vs. 27 (9) mm Hg], and peak inspiratory flow [0.878 (0.234) vs. 0.533 (0.105) L/s], all p < 0.0001. Dynamic lung compliance (≥ 0.025 L/cm H2O) decreased after ROSC in bag-valve group but was maintained in VLP2000E group [0.019 (0.006) vs. 0.024 (0.008) L/cm H2O, p = 0.0003].

CONCLUSIONS

VLP2000E ventilation during CPR is feasible and equivalent to bag-valve ventilation in ROSC rate and arterial oxygen saturation. It produces better respiratory parameters, with lower airway pressure and tidal volume. VLP2000E ventilation also prevents the significant decrease of dynamic lung compliance observed after bag-valve ventilation. Further preclinical studies confirming these findings would be interesting.

Advanced airway management for pediatric out-of-hospital cardiac arrest: A systematic review and network meta-analysis

OBJECTIVES

Although airway management is important in pediatric resuscitation, the effectiveness of bag-mask ventilation (BMV) and advanced airway management (AAM), such as endotracheal intubation (ETI) and supraglottic airway (SGA) devices, for prehospital resuscitation of pediatric out-of-hospital cardiac arrest (OHCA) remains unclear. We aimed to determine the efficacy of AAM during prehospital resuscitation of pediatric OHCA cases.

METHODS

We searched four databases from their inception to November 2022 and included randomized controlled trials and observational studies with appropriate adjustments for confounders that evaluated prehospital AAM for OHCA in children aged <18 years in quantitative synthesis. We compared three interventions (BMV, ETI, and SGA) via network meta-analysis using the GRADE Working Group approach. The outcome measures were survival and favorable neurological outcomes at hospital discharge or 1 month after cardiac arrest.

RESULTS

Five studies (including one clinical trial and four cohort studies with rigorous confounding adjustment) involving 4852 patients were analyzed in our quantitative synthesis. Compared with ETI, BMV was associated with survival (relative risk [RR] 0.44 [95% confidence intervals (CI) 0.25-0.77]) (very low certainty). There were no significant association with survival in the other comparisons (SGA vs. BMV: RR 0.62 [95% CI 0.33-1.15] [low certainty], ETI vs. SGA: RR 0.71 [95% CI 0.39-1.32] [very low certainty]). There was no significant association with favorable neurological outcomes in any comparison (ETI vs. BMV: RR 0.33 [95% CI 0.11-1.02]; SGA vs. BMV: RR 0.50 [95% CI 0.14-1.80]; ETI vs. SGA: RR 0.66 [95% CI 0.18-2.46]) (all very low certainty). In the ranking analysis, the hierarches for efficacy for survival and favorable neurological outcome were BMV > SGA > ETI.

CONCLUSION

Although the available evidence is from observational studies and its certainty is low to very low, prehospital AAM for pediatric OHCA did not improve outcomes.

Rat model of asphyxia-induced cardiac arrest and resuscitation

Neurologic injury after cardiopulmonary resuscitation is the main cause of the low survival rate and poor quality of life among patients who have experienced cardiac arrest. In the United States, as the American Heart Association reported, emergency medical services respond to more than 347,000 adults and more than 7,000 children with out-of-hospital cardiac arrest each year. In-hospital cardiac arrest is estimated to occur in 9.7 per 1,000 adult cardiac arrests and 2.7 pediatric events per 1,000 hospitalizations. Yet the pathophysiological mechanisms of this injury remain unclear. Experimental animal models are valuable for exploring the etiologies and mechanisms of diseases and their interventions. In this review, we summarize how to establish a standardized rat model of asphyxia-induced cardiac arrest. There are four key focal areas: (1) selection of animal species; (2) factors to consider during modeling; (3) intervention management after return of spontaneous circulation; and (4) evaluation of neurologic function. The aim was to simplify a complex animal model, toward clarifying cardiac arrest pathophysiological processes. It also aimed to help standardize model establishment, toward facilitating experiment homogenization, convenient interexperimental comparisons, and translation of experimental results to clinical application.

Ten rules for optimizing ventilatory settings and targets in post-cardiac arrest patients

Cardiac arrest (CA) is a major cause of morbidity and mortality frequently associated with neurological and systemic involvement. Supportive therapeutic strategies such as mechanical ventilation, hemodynamic settings, and temperature management have been implemented in the last decade in post-CA patients, aiming at protecting both the brain and the lungs and preventing systemic complications. A lung-protective ventilator strategy is currently the standard of care among critically ill patients since it demonstrated beneficial effects on mortality, ventilator-free days, and other clinical outcomes. The role of protective and personalized mechanical ventilation setting in patients without acute respiratory distress syndrome and after CA is becoming more evident. The individual effect of different parameters of lung-protective ventilation, including mechanical power as well as the optimal oxygen and carbon dioxide targets, on clinical outcomes is a matter of debate in post-CA patients. The management of hemodynamics and temperature in post-CA patients represents critical steps for obtaining clinical improvement. The aim of this review is to summarize and discuss current evidence on how to optimize mechanical ventilation in post-CA patients. We will provide ten tips and key insights to apply a lung-protective ventilator strategy in post-CA patients, considering the interplay between the lungs and other systems and organs, including the brain.

Oxygen targets and 6-month outcome after out of hospital cardiac arrest: a pre-planned sub-analysis of the targeted hypothermia versus targeted normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial

BACKGROUND

Optimal oxygen targets in patients resuscitated after cardiac arrest are uncertain. The primary aim of this study was to describe the values of partial pressure of oxygen values (PaO₂) and the episodes of hypoxemia and hyperoxemia occurring within the first 72 h of mechanical ventilation in out of hospital cardiac arrest (OHCA) patients. The secondary aim was to evaluate the association of PaO₂ with patients' outcome.

METHODS

Preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after OHCA (TTM2) trial. Arterial blood gases values were collected from randomization every 4 h for the first 32 h, and then, every 8 h until day 3. Hypoxemia was defined as PaO₂ < 60 mmHg and severe hyperoxemia as PaO₂ > 300 mmHg. Mortality and poor neurological outcome (defined according to modified Rankin scale) were collected at 6 months.

RESULTS

1418 patients were included in the analysis. The mean age was 64 ± 14 years, and 292 patients (20.6%) were female. 24.9% of patients had at least one episode of hypoxemia, and 7.6% of patients had at least one episode of severe hyperoxemia. Both hypoxemia and hyperoxemia were independently associated with 6-month mortality, but not with poor neurological outcome. The best cutoff point associated with 6-month mortality for hypoxemia was 69 mmHg (Risk Ratio, RR = 1.009, 95% CI 0.93-1.09), and for hyperoxemia was 195 mmHg (RR = 1.006, 95% CI 0.95-1.06). The time exposure, i.e., the area under the curve (PaO₂-AUC), for hyperoxemia was significantly associated with mortality (p = 0.003).

CONCLUSIONS

In OHCA patients, both hypoxemia and hyperoxemia are associated with 6-months mortality, with an effect mediated by the timing exposure to high values of oxygen. Precise titration of oxygen levels should be considered in this group of patients.

TRIAL REGISTRATION

clinicaltrials.gov NCT02908308 , Registered September 20, 2016.

High PEEP Levels during CPR Improve Ventilation without Deleterious Haemodynamic Effects in Pigs

Background: Invasive ventilation during cardiopulmonary resuscitation (CPR) is very complex due to unique thoracic pressure conditions. Current guidelines do not provide specific recommendations for ventilation during ongoing chest compressions regarding positive end-expiratory pressure (PEEP). This trial examines the cardiopulmonary effects of PEEP application during CPR. Methods: Forty-two German landrace pigs were anaesthetised, instrumented, and randomised into six intervention groups. Three PEEP levels (0, 8, and 16 mbar) were compared in high standard and ultralow tidal volume ventilation. After the induction of ventricular fibrillation, mechanical chest compressions and ventilation were initiated and maintained for thirty minutes. Blood gases, ventilation/perfusion ratio, and electrical impedance tomography loops were taken repeatedly. Ventilation pressures and haemodynamic parameters were measured continuously. Postmortem lung tissue damage was assessed using the diffuse alveolar damage (DAD) score. Statistical analyses were performed using SPSS, and p values <0.05 were considered significant. Results: The driving pressure (Pdrive) showed significantly lower values when using PEEP 16 mbar than when using PEEP 8 mbar (p = 0.045) or PEEP 0 mbar (p < 0.001) when adjusted for the ventilation mode. Substantially increased overall lung damage was detected in the PEEP 0 mbar group (vs. PEEP 8 mbar, p = 0.038; vs. PEEP 16 mbar, p = 0.009). No significant differences in mean arterial pressure could be detected. Conclusion: The use of PEEP during CPR seems beneficial because it optimises ventilation pressures and reduces lung damage without significantly compromising blood pressure. Further studies are needed to examine long-term effects in resuscitated animals.

Quality Evaluation Algorithm for Chest Compressions Based on OpenPose Model

Aiming at the problems of the low evaluation efficiency of the existing traditional cardiopulmonary resuscitation (CPR) training mode and the considerable development of machine vision technology, a quality evaluation algorithm for chest compressions (CCs) based on the OpenPose human pose estimation (HPE) model is proposed. Firstly, five evaluation criteria are proposed based on major international CPR guidelines along with our experimental study on elbow straightness. Then, the OpenPose network is applied to obtain the coordinates of the key points of the human skeleton. The algorithm subsequently calculates the geometric angles and displacement of the selected joint key points using the detected coordinates. Finally, it determines whether the compression posture is standard, and it calculates the depth, frequency, position and chest rebound, which are the critical evaluation metrics of CCs. Experimental results show that the average accuracy of network behavior detection reaches 94.85%, and detection speed reaches 25 fps.

Prehospital airway management for out-of-hospital cardiac arrest: A nationwide multicenter study from the KoCARC registry

AIM

This study investigated whether prehospital advanced airway management (AAM) is associated with improved survival of out-of-hospital cardiac arrest (OHCA) compared with conventional bag-valve-mask (BVM) ventilation.

METHODS

We investigated the neurologically favorable survival of adult patients with OHCA who underwent BVM or AAM using the Korean Cardiac Arrest Research Consortium (KoCARC), a multicenter OHCA registry of Korea. The differences in clinical characteristics were adjusted by matching or weighting the clinical propensity for use of AAM or by least absolute shrinkage and selection operator (LASSO). The primary outcome was 30-day survival with neurologically favorable status defined by cerebral performance category 1 or 2.

RESULTS

Of the 9,616 patients enrolled (median age = 71 years; 65% male), there were 6,243 AAM and 3,354 BVM patients. In unadjusted analysis, the 30-day neurologically favorable survival was lower in the AAM group compared with the BVM group (5.5% vs. 10.0%; hazard ratio [HR] = 1.21, 95% confidence interval [CI] = 1.16 to 1.27; all p < 0.001). In propensity score matching-adjusted analysis, these differences were not found (9.6% vs. 10.0%; HR = 0.98, 95% CI = 0.93 to 1.03, p > 0.05). Inverse probability of treatment weighting- and LASSO-adjusted analyses replicated these results.

CONCLUSIONS

In this nationwide real-world data analysis of OHCA, the 30-day neurologically favorable survival did not differ between prehospital AAM and BVM after adjustment for clinical characteristics.

Real-Time Monitoring of Blood Parameters in the Intensive Care Unit: State-of-the-Art and Perspectives

The number of patients in intensive care units has increased over the past years. Critically ill patients are treated with a real time support of the instruments that offer monitoring of relevant blood parameters. These parameters include blood gases, lactate, and glucose, as well as pH and temperature. Considering the COVID-19 pandemic, continuous management of dynamic deteriorating parameters in patients is more relevant than ever before. This narrative review aims to summarize the currently available literature regarding real-time monitoring of blood parameters in intensive care. Both, invasive and non-invasive methods are described in detail and discussed in terms of general advantages and disadvantages particularly in context of their use in different medical fields but especially in critical care. The objective is to explicate both, well-known and frequently used as well as relatively unknown devices. Furtehrmore, potential future direction in research and development of realtime sensor systems are discussed. Therefore, the discussion section provides a brief description of current developments in biosensing with special emphasis on their technical implementation. In connection with these developments, the authors focus on different electrochemical approaches to invasive and non-invasive measurements in vivo.

Prehospital Cardiac Arrest Airway Management: An NAEMSP Position Statement and Resource Document

Airway management is a critical component of out-of-hospital cardiac arrest (OHCA) resuscitation. Multiple cardiac arrest airway management techniques are available to EMS clinicians including bag-valve-mask (BVM) ventilation, supraglottic airways (SGAs), and endotracheal intubation (ETI). Important goals include achieving optimal oxygenation and ventilation while minimizing negative effects on physiology and interference with other resuscitation interventions. NAEMSP recommends:Based on the skill of the clinician and available resources, BVM, SGA, or ETI may be considered as airway management strategies in OHCA.Airway management should not interfere with other key resuscitation interventions such as high-quality chest compressions, rapid defibrillation, and treatment of reversible causes of the cardiac arrest.EMS clinicians should take measures to avoid hyperventilation during cardiac arrest resuscitation.Where available for clinician use, capnography should be used to guide ventilation and chest compressions, confirm and monitor advanced airway placement, identify return of spontaneous circulation (ROSC), and assist in the decision to terminate resuscitation.

Association between the types of bystander cardiopulmonary resuscitation and the survival with good neurologic outcome of preschool pediatric out-of-hospital cardiac arrest cases in Japan: A propensity score matching analysis using an extended nationwide database

BACKGROUND

Pediatric out-of-hospital cardiac arrests (OHCAs) are frequently associated with a respiratory etiology. Despite the high proportion of preschool children with OHCAs, very few studies on this special population exist. This study characterizes the epidemiologic features of preschool pediatric OHCAs and analyzes the advantage of conventional (ventilations with chest compressions) bystander cardiopulmonary resuscitation (CPR) over compression-only bystander CPR (BCPR) on the one-month post-event neurological status of the patient.

METHODS

Japanese nationwide databases for all ambulance transport events and OHCAs occurring during a 4-year period between 2016 and 2019 were combined, totalling 3,608 patient events. Children ≤6-years-old were included; physician- and EMS-witnessed events, no prehospital resuscitation effort events, and neonatal patient events were excluded. Neurologically favorable 1-month survival rates were compared among groups using univariate and multivariate analyses before and after propensity score matching.

RESULTS

From the combined database, 2,882 pediatric OHCAs meeting selection criteria were categorized as no BCPR (984), compression-only BCPR (1,428), and conventional BCPR (470). The proportion of bystander-witnessed cases was low (22.3%). Most OHCA witnesses were family members (88.5%), and most OHCAs occurred at home (88.0%). The neurologically favorable 1-month survival rates were: no BCPR 2.4%, compression only, 3.2%, and conventional 6.6% (P < 0.01). Multivariate logistic regression analysis before and after matching showed that conventional BCPR was associated with higher neurologically favorable 1-month survival than compression-only BCPR. Subgroup analyses after matching demonstrated that conventional BCPR was associated with better outcomes in nonmedical (adjusted odds ratio; 95% confidence interval, 2.83; 1.09-7.32) and unwitnessed OHCA cases (3.42; 1.09-10.8).

CONCLUSIONS

Conventional CPR is rarely performed by bystanders in preschool pediatric OHCA. However, conventional BCPR results in neurologically favorable outcomes in nonmedical and unwitnessed cases.

Effect of Early Supraglottic Airway Device Insertion on Chest Compression Fraction during Simulated Out-of-Hospital Cardiac Arrest: Randomised Controlled Trial

Early insertion of a supraglottic airway (SGA) device could improve chest compression fraction by allowing providers to perform continuous chest compressions or by shortening the interruptions needed to deliver ventilations. SGA devices do not require the same expertise as endotracheal intubation. This study aimed to determine whether the immediate insertion of an i-gel^® while providing continuous chest compressions with asynchronous ventilations could generate higher CCFs than the standard 30:2 approach using a face-mask in a simulation of out-of-hospital cardiac arrest. A multicentre, parallel, randomised, superiority, simulation study was carried out. The primary outcome was the difference in CCF during the first two minutes of resuscitation. Overall and per-cycle CCF quality of compressions and ventilations parameters were also compared. Among thirteen teams of two participants, the early insertion of an i-gel^® resulted in higher CCFs during the first two minutes (89.0% vs. 83.6%, p = 0.001). Overall and per-cycle CCF were consistently higher in the i-gel^® group, even after the 30:2 alternation had been resumed. In the i-gel^® group, ventilation parameters were enhanced, but compressions were significantly shallower (4.6 cm vs. 5.2 cm, p = 0.007). This latter issue must be addressed before clinical trials can be considered.

Comparison of VividTrac, King Vision and Macintosh laryngoscopes in normal and difficult airways during simulated cardiopulmonary resuscitation among novices

Introduction

Early endotracheal intubation improves neurological outcomes in cardiopulmonary resuscitation, although cardiopulmonary resuscitation is initially carried out by personnel with limited experience in a significant proportion of cases. Videolaryngoscopes might decrease the number of attempts and time needed, especially among novices. We sought to compare videolaryngoscopes with direct laryngoscopes in simulated cardiopulmonary resuscitation scenarios.

Materials and methods

Forty-four medical students were recruited to serve as novice users. Following brief, standardized training, students executed endotracheal intubation with the King Vision^®, Macintosh and VividTrac^® laryngoscopes, on a cardiopulmonary resuscitation trainer in normal and difficult airway scenarios. We evaluated the time to and proportion of successful intubation, the best view of the glottis, esophageal intubation, dental trauma and user satisfaction.

Results

In the normal airway scenario, significantly shorter intubation times were achieved using the King Vision^® than the Macintosh laryngoscope. In the difficult airway scenario, we found that the VividTrac^® was superior to the King Vision^® and Macintosh laryngoscopes in the laryngoscopy time. In both scenarios, we noted no difference in the first-attempt success rate, but the best view of the glottis and dental trauma, esophageal intubation and bougie use were more frequent with the Macintosh laryngoscope than with the videolaryngoscopes. The shortest tube insertion times were achieved using the King Vision^® in both scenarios.

Conclusion

All providers achieved successful intubation within three attempts, but we found no device superior in any of our scenarios regarding the first-attempt success rate. The King Vision^® was superior to the Macintosh laryngoscope in the intubation time in the normal airway scenario and noninferior in the difficult airway scenario for novice users. We noted significantly less esophageal intubation using the videolaryngoscopes than using the Macintosh laryngoscope in both scenarios. Based on our results, the KingVision^® might be recommended over the VividTrac^® and Macintosh laryngoscopes for further evaluation.

[I-Gel® laryngeal mask versus bag-valve-mask in instrumental cardiopulmonary resuscitation under capnographic monitoring: Cluster-randomized pilot clinical trial]

OBJECTIVE

To compare the basic airway and the advanced airway with the supraglottic device I-Gel®, by means of capnography during intermediate CPR.

DESIGN

Randomized experimental pilot study by groups.

SETTING

Out-hospital care basic life support units on the Island of Mallorca.

PARTICIPANTS

Adults attended after cardiorespiratory arrest of non-traumatic origin.

INTERVENTIONS

Advanced airway management during instrumental CPR with I-Gel® or basic CPR with bag-valve-mask, under capnographic monitoring.

MAIN MEASUREMENTS

Capnometric levels obtained according to the device used, number of insertions of the I-Gel®, cases without achieving correct insertion/ventilation by branches, achievement of ROSC in CPR and number of hospital live admissions.

RESULTS

Twenty-three cases were recruited for analysis. The insertion success rate of the I-Gel® was 92.9% at the first attempt, the mean capnometric values were 16.3mmHg in the control group and 27.4% in the intervention group. 34.8% (n=8) of the patients achieved spontaneous circulation recovery at some point and 26.1% (n=6) were admitted to hospital alive. The survival analysis, taking into account the arrival of the unit and the first minute of ventilations recorded together with the variable hospital admission, suggests a certain trend of greater survival in the intervention branch (P=.066).

CONCLUSIONS

The use of I-Gel® raises an improvement in the ventilation of the patients in PCR, evidenced by the mean capnometric values in the intervention group, finding no correlation with CPR outcome variables.

CPR with restricted patient access using alternative rescuer positions: a randomised cross-over manikin study simulating the CPR scenario after avalanche burial

Background

The aim of this manikin study was to evaluate the quality of cardiopulmonary resuscitation (CPR) with restricted patient access during simulated avalanche rescue using over-the-head and straddle position as compared to standard position.

Methods

In this prospective, randomised cross-over study, 25 medical students (64% male, mean age 24) performed single-rescuer CPR with restricted patient access in over-the-head and straddle position using mouth-to-mouth ventilation or pocket mask ventilation. Chest compression depth, rate, hand position, recoil, compression/decompression ratio, hands-off times, tidal volume of ventilation and gastric insufflation were compared to CPR with unrestricted patient access in standard position.

Results

Only 28% of all tidal volumes conformed to the guidelines (400–800 ml), 59% were below 400 ml and 13% were above 800 ml. There was no significant difference in ventilation parameters when comparing standard to atypical rescuer positions. Participants performed sufficient chest compressions depth in 98.1%, a minimum rate in 94.7%, correct compression recoil in 43.8% and correct hand position in 97.3% with no difference between standard and atypical rescuer positions. In 36.9% hands-off times were longer than 9 s.

Conclusions

Efficacy of CPR from an atypical rescuer position with restricted patient access is comparable to CPR in standard rescuer position. Our data suggest to start basic life-support before complete extrication in order to reduce the duration of untreated cardiac arrest in avalanche rescue. Ventilation quality provided by lay rescuers may be a limiting factor in resuscitation situations where rescue ventilation is considered essential.

Effect of positive end-expiratory pressure on additional passive ventilation generated by CPR compressions in a porcine model

Background

Compressions given during cardiopulmonary resuscitation generate small, ineffective passive ventilations through oscillating waves. Positive end-expiratory pressure increases the volume of these passive ventilations; however, its effect on passive ventilation is unknown. Our objective was to determine if increasing positive end-expiratory pressure during cardiopulmonary resuscitation increases passive ventilation generated by compressions to a clinically significant point. This study was conducted on 13 Landrace-Yorkshire pigs. After inducing cardiac arrest with bupivacaine, cardiopulmonary resuscitation was performed with a LUCAS 3.1. During cardiopulmonary resuscitation, pigs were ventilated at a positive end-expiratory pressure of 0, 5, 10, 15, 20 cmH₂O (randomly determined) for 9 min. Using the NM3 respiratory monitoring device, expired minute ventilation and volumetric capnography were measured. Arterial blood gas was obtained for each positive end-expiratory pressure level to compare the effects of positive end-expiratory pressure on carbon dioxide.

Results

Increasing positive end-expiratory pressure from 0 to 20 cmH₂O increased the mean (SEM) expired minute ventilation from 6.33 (0.04) to 7.33 (0.04) mL/min. With the 5-cmH₂O incremental increases in positive end-expiratory pressure from 0 to 20 cmH₂O, volumetric capnography increased from a mean (SEM) of 94.19 (0.78) to 115.18 (0.8) mL/min, except for 15 cmH₂O, which showed greater carbon dioxide exhalation with volumetric capnography compared with 20 cmH₂O. PCO₂ declined significantly as positive end-expiratory pressure was increased from 0 to 20 cmH₂O.

Conclusions

When increasing positive end-expiratory pressure from 0 to 20, the contribution to overall ventilation from gas oscillations generated by the compressions became more significant, and may even lead to hypocapnia, especially when using positive end-expiratory pressures between 15 and 20.

Continuous flow insufflation of oxygen compared with manual ventilation during out-of-hospital cardiac arrest: A survey of the paramedics

Introduction:

In 2018, a continuous flow insufflation of oxygen (CFIO) device (b-card™, Vygon (USA)) placed on a supraglottic airway (SGA) became the standard of care to ventilate patients during adult out-of-hospital cardiac arrest (OHCA) care in Quebec–Capitale-Nationale region, Canada. This study aims to assess the paramedics’ perception as well as the disadvantages and the benefits relative to the use of CFIO during OHCA management.

Methods:

An invitation to complete an online survey (Survey Monkey™) was sent to all 560 paramedics who are working in our region. The survey included 22 questions of which 9 aimed to compare the traditional manual ventilation with a bag to the CFIO using a 5-point Likert-type scale.

Results:

A total of 244 paramedics completed the survey, of which 189 (77.5%) had used the CFIO device during an OHCA at least once. Most respondents felt that the intervention was faster (70.2%) and easier (86.5%) with the CFIO device compared with manual ventilation. CFIO was also associated with perceived increased patient safety (64.4%) as well as paramedic safety during the evacuation (88.9%) and the ambulance transport (88.9%). Paramedics reported that physical (48.1%) and cognitive (52.9%) fatigue were also improved with CFIO. The main reported barriers were the bending of the external SGA tube and the loss of capnography values.

Conclusion:

The use of CFIO during adult OHCA care allows a simplified approach and was perceived as safer for the patient and the paramedics compared with manual ventilation. Its impact on patient-centred outcomes needs to be assessed.

EEG-Based Prediction of the Recovery of Carotid Blood Flow during Cardiopulmonary Resuscitation in a Swine Model

The recovery of cerebral circulation during cardiopulmonary resuscitation (CPR) is important to improve the neurologic outcomes of cardiac arrest patients. To evaluate the feasibility of an electroencephalogram (EEG)-based prediction model as a CPR feedback indicator of high- or low-CBF carotid blood flow (CBF), the frontal EEG and hemodynamic data including CBF were measured during animal experiments with a ventricular fibrillation (VF) swine model. The most significant 10 EEG parameters in the time, frequency and entropy domains were determined by neighborhood component analysis and Student’s t-test for discriminating high- or low-CBF recovery with a division criterion of 30%. As a binary CBF classifier, the performances of logistic regression, support vector machine (SVM), k-nearest neighbor, random forest and multilayer perceptron algorithms were compared with eight-fold cross-validation. The three-order polynomial kernel-based SVM model showed the best accuracy of 0.853. The sensitivity, specificity, F1 score and area under the curve of the SVM model were 0.807, 0.906, 0.853 and 0.909, respectively. An automated CBF classifier derived from non-invasive EEG is feasible as a potential indicator of the CBF recovery during CPR in a VF swine model.

Use of supraglottic airway devices under capnography monitoring during cardiopulmonary resuscitation: A systematic review

BACKGROUND

Bag-valve-mask ventilation is the most commonly applied method during cardiopulmonary resuscitation. Globally, advanced airway management with blind insertion devices such as supraglottic airway devices has been implemented for years by different emergency services. The efficiency of ventilation via such devices could be measured by capnography.

OBJECTIVE

The objective of this study was to determine whether capnography is useful in patients undergoing cardiopulmonary resuscitation and to assess the effectiveness of ventilation via supraglottic airway devices.

REVIEW METHODS USED

This is a systematic review written following the steps of Preferred Reporting Items for Systematic Review and Meta-analyses protocols.

DATA SOURCES

A bibliographic search was carried out from the following databases: EBSCOhost, Scopus, EMBASE, Virtual Health Library, PubMed, Cochrane Library, Spanish Medical Index, Spanish Bibliographic Index in Health Sciences, and Latin American and Caribbean Health Sciences Literature, from inception until September 2019.

REVIEW METHODS

Studies describing the use of capnography with supraglottic airway devices during cardiopulmonary resuscitation manoeuvres were selected and evaluated using the Critical Appraisal Skills Programme.

RESULTS

Twenty-four articles were identified by title and abstract: six were randomised clinical trials, 11 were nonrandomised clinical trials, six were descriptive prospective studies, and one was a descriptive retrospective study. Nine primary research articles were selected for synthesis. Only one provided objective values of capnography obtained with ventilation with these devices, correlating them with the results of resuscitation.

CONCLUSIONS

The evidence published so far is scarce, mostly from observational studies with high risk of bias in general. Although a degree of recommendation cannot be established, some results indicate that capnography has the potential to facilitate advanced clinical practice of ventilation with supraglottic airway devices during cardiopulmonary resuscitation.

Continuous flow insufflation of oxygen for cardiac arrest: Systematic review of human and animal model studies

OBJECTIVE

To synthetize the evidence regarding the effect of constant flow insufflation of oxygen (CFIO) on the rate of return of spontaneous circulation (ROSC) and other clinical outcomes during cardiac arrest (CA).

METHODS

A systematic review was performed using four databases (PROSPERO: CRD42020071960). Studies reporting on adult CA patients or on animal models simulating CA and assessing the effect of CFIO on ROSC or other clinical outcomes were considered.

RESULTS

A total of 3540 citations were identified, of which 16 studies were included. Four studies (two randomized controlled trials (RCT), two cohort studies), reported on humans while 12 studies used animal models. No meta-analysis was performed due to clinical heterogeneity. There were no differences in the ROSC (18.9% vs 20.8%, p = 0.99; 27.1% vs 21.3%, p = 0.51) and sustained ROSC rates (16.1% vs 17.3%, p = 0.81; 12.5% vs 14.9%, p = 0.73) with CFIO compared to intermitant positive pressure ventilation (IPPV) in the two human RCTs. Survival to ICU discharge was similar between CFIO (2.3%) and IPPV (2.3%) in the largest RCT (p = 0.96). Human studies were at serious or high risk of bias. In animal models' studies, ROSC rates were presented in seven RCTs. CFIO was superior to IPPV in one trial, but was associated with similar ROSC rates using different ventilation strategies in the remaining six studies.

CONCLUSIONS

No definitive association between CFIO and ROSC, sustained ROSC or survival compared to other ventilation strategies could be demonstrated. Future studies should assess CFIO effect on post-survival neurological functions and patient-important CA outcomes.

Effect on Chest Compression Fraction of Continuous Manual Compressions with Asynchronous Ventilations Using an i-gel® versus 30:2 Approach during Simulated Out-of-Hospital Cardiac Arrest: Protocol for a Manikin Multicenter Randomized Controlled Trial

The optimal airway management strategy during cardiopulmonary resuscitation is uncertain. In the case of out-of-hospital cardiac arrest, a high chest compression fraction is paramount to obtain the return of spontaneous circulation and improve survival and neurological outcomes. To improve this fraction, providing continuous chest compressions should be more effective than using the conventional 30:2 ratio. Airway management should, however, be adapted, since face-mask ventilation can hardly be carried out while continuous compressions are administered. The early insertion of a supraglottic device could therefore improve the chest compression fraction by allowing ventilation while maintaining compressions. This is a protocol for a multicenter, parallel, randomized simulation study. Depending on randomization, each team made up of paramedics and emergency medical technicians will manage the 10-min scenario according either to the standard approach (30 compressions with two face-mask ventilations) or to the experimental approach (continuous manual compressions with early insertion of an i-gel® supraglottic device to deliver asynchronous ventilations). The primary outcome will be the chest compression fraction during the first two minutes of cardiopulmonary resuscitation. Secondary outcomes will be chest compression fraction (per cycle and overall), compressions and ventilations quality, time to first shock and to first ventilation, user satisfaction, and providers' self-assessed cognitive load.

Bag-Valve-Mask versus Laryngeal Mask Airway Ventilation in Cardiopulmonary Resuscitation with Continuous Compressions: A Simulation Study

INTRODUCTION

The 2017 International Liaison Committee on Resuscitation (ILCOR) guideline recommends that Emergency Medical Service (EMS) providers can perform cardiopulmonary resuscitation (CPR) with synchronous or asynchronous ventilation until an advanced airway has been placed. In the current literature, limited data on CPR performed with continuous compressions and asynchronous ventilation with bag-valve-mask (BVM) are available.

STUDY OBJECTIVE

In this study, researchers aimed to compare the effectiveness of asynchronous BVM and laryngeal mask airway (LMA) ventilation during CPR with continuous chest compressions.

METHODS

Emergency medicine residents and interns were included in the study. The participants were randomly assigned to resuscitation teams with two rescuers. The cross-over simulation study was conducted on two CPR scenarios: asynchronous ventilation via BVM during a continuous chest compression and asynchronous ventilation via LMA during a continuous chest compression in cardiac arrest patient with asystole. The primary endpoints were the ventilation-related measurements.

RESULTS

A total of 92 volunteers were included in the study and 46 CPRs were performed in each group. The mean rate of ventilations of the LMA group was significantly higher than that of the BVM group (13.7 [11.7-15.7] versus 8.9 [7.5-10.3] breaths/minute; P <.001). The mean volume of ventilations of the LMA group was significantly higher than that of the BVM group (358.4 [342.3-374.4] ml versus 321.5 [303.9-339.0] ml; P = .002). The mean minute ventilation volume of the LMA group was significantly higher than that of the BVM group (4.88 [4.15-5.61] versus 2.99 [2.41-3.57] L/minute; P <.001). Ventilations exceeding the maximum volume limit occurred in two (4.3%) CPRs in the BVM group and in 11 (23.9%) CPRs in the LMA group (P = .008).

CONCLUSION

The results of this study show that asynchronous BVM ventilation with continuous chest compressions is a reliable and effective strategy during CPR under simulation conditions. The clinical impact of these findings in actual cardiac arrest patients should be evaluated with further studies at real-life scenes.

Duration of exposure to a prehospital advanced airway and neurological outcome for out-of-hospital cardiac arrest: A retrospective cohort study

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) studies have focused on the benefits and harms of placing an intra-arrest advanced airway, but few studies have evaluated the benefits and harms after successful placement. We hypothesize that increased time in the tumultuous prehospital environment after intra-arrest advanced airway placement results in reduced patient survival.

METHODS

This was a secondary analysis of adult, non-traumatic, OHCA patients with an advanced airway placed in the PRIMED trial. The exposure variable was the time interval between successful advanced airway placement and Emergency Department (ED) arrival. The outcome was cerebral performance category (CPC) 1 or 2 at hospital discharge. Multivariable logistic regression, adjusted for Utstein variables and resuscitation-associated time intervals, was used to estimate adjusted odds ratios (aOR).

RESULTS

The cohort of complete cases included 4779 patients. The median time exposed to a prehospital advanced airway was 27 min (IQR 20-35). The total prehospital time was 39.4 min (IQR 32.3-48.1). An advanced airway was placed intra-arrest in 3830 cases (80.1%) and post-return of spontaneous circulation (post-ROSC) in 949 cases (19.9%). Overall, 486 (10.2%) of the cohort achieved the CPC outcome, but this was higher in the post-ROSC (21.7%) versus intra-arrest (7.5%) cohort. CPC was not associated with the time interval from advanced airway placement to ED arrival in the intra-arrest airway cohort (aOR 0.98, 95%CI 0.94-1.01).

CONCLUSIONS

In OHCA patients who receive an intra-arrest advanced airway, longer time intervals exposed to a prehospital advanced airway are not associated with reduced patient survival.

Comparison of cardiopulmonary resuscitation that applied synchronous 30 compressions–2 ventilations with that applied asynchronous 110/min compression–10/min ventilation: A mannequin study

Background:

CPR model of a resuscitation to be ventilated with a bag valve mask constitutes a discussion when evaluated with the current guidance.

Objective:

This study aims to compare the synchronous (30–2) ventilation–compression method with asynchronous 110/min compression–10/min ventilation in cardiac arrests where an advanced airway management is not applied and where ventilation is provided by a bag valve mask on a mannequin.

Methods:

This simulation trial was performed using two clinical cardiopulmonary resuscitation scenarios: an asynchronous scenario with 10 ventilations per minute asynchronously when compression is applied as 110 compression per minute and a synchronous scenario in which 30 compressions:2 ventilations were performed synchronously. A total of 100 people in 50 groups applied these two scenarios on mannequin. Ventilation and compression data of both scenarios were recorded.

Results:

Evaluating the compression criteria in both the scenarios performed by 50 groups in total, in terms of all criteria except compression fraction, there was no statistically difference between the two scenarios (p > 0.05). Compression fraction values in the asynchronous scenario were found to be statistically significantly higher than the synchronous scenario (96.02 ± 2.35, 81.34 ± 4.42, p < 0.001). Evaluating the ventilation criteria in both the scenarios performed by 50 groups in total; there was a statistically significant difference in all criteria. Mean ventilation rate of the asynchronous scenario was statistically higher than the synchronous scenario (7.22 ± 2.42, 5.08 ± 0.75, p < 0.001). Mean ventilation volume of the synchronous scenario was statistically higher than the asynchronous scenario (353.24 ± 45.46, 527.40 ± 96.60, p < 0.001). Ventilation ratio in sufficient volume of the synchronous scenario was statistically higher than the asynchronous scenario (36.84 ± 14.47, 75.00 ± 21.24, p < 0.001). Ventilation ratio below the minimum volume limit of the asynchronous scenario was statistically higher than the synchronous scenario (62.48 ± 14.72, 17.86 ± 19.50, p < 0.001).

Conclusion:

In our study, we concluded that the cardiopulmonary resuscitation applied by the synchronous method reached better ventilation volumes. Evaluating together with any interruption in compression, comprehensive studies are needed to reveal which patients would benefit from this result.

Oxygen administration in patients recovering from cardiac arrest: a narrative review

High oxygen tension in blood and/or tissue affects clinical outcomes in several diseases. Thus, the optimal target PaO₂ for patients recovering from cardiac arrest (CA) has been extensively examined. Many patients develop hypoxic brain injury after the return of spontaneous circulation (ROSC); this supports the need for oxygen administration in patients after CA. Insufficient oxygen delivery due to decreased blood flow to cerebral tissue during CA results in hypoxic brain injury. By contrast, hyperoxia may increase dissolved oxygen in the blood and, subsequently, generate reactive oxygen species that are harmful to neuronal cells. This secondary brain injury is particularly concerning. Although several clinical studies demonstrated that hyperoxia during post-CA care was associated with poor neurological outcomes, considerable debate is ongoing because of inconsistent results. Potential reasons for the conflicting results include differences in the definition of hyperoxia, the timing of exposure to hyperoxia, and PaO₂ values used in analyses. Despite the conflicts, exposure to PaO₂ > 300 mmHg through administration of unnecessary oxygen should be avoided because no obvious benefit has been demonstrated. The feasibility of titrating oxygen administration by targeting SpO₂ at approximately 94% in patients recovering from CA has been demonstrated in pilot randomized controlled trials (RCTs). Such protocols should be further examined.

Efficacy of Amflow®, a Real-Time-Portable Feedback Device for Delivering Appropriate Ventilation in Critically Ill Patients: A Randomised, Controlled, Cross-Over Simulation Study

Objective

The aim of this study was to test whether Amflow® (a newly designed portable ventilation feedback device) can assist rescuers in delivering target tidal volume (V _T) and respiration rate (RR) during self-inflating bag (SB) ventilations in various clinical scenarios.

Method

This was a simulation study with a prospective cross-over design. A total of 40 trained participants who underwent training for SB ventilation were recruited. Using a SB with or without Amflow® alternately, participants delivered ventilations to test lungs connected to a gas flow analyser in each of three different scenarios: acute respiratory distress syndrome (ARDS; 315-385 ml ranges for 350 ml target V _T, with 20 breaths/min); cardiopulmonary resuscitation (CPR; 450-550 ml ranges for 500 ml target V _T with 10 breaths/min); and adult head trauma (630-770 ml ranges for 700 ml target V _T with 15 breaths/min).

Results

The feedback group (SB with Amflow®) demonstrated a significantly higher percentage of delivering the appropriate V _T ranges than the no-feedback group for both ARDS (58.6% versus 23.5%, respectively) and CPR (85.4% versus 41.0%, respectively) (all p < 0.05). However, there was no significant difference between the two groups in the percentage of delivering the appropriate V _T ranges in head trauma patients (65.9% versus 68.3%, respectively; p=0.092). In all three scenarios, a higher percentage of target RR delivered was achieved in the feedback group (88.3%, 99.2%, and 96.3%, respectively) compared with the no-feedback group (5.8%, 12.5%, and 10.0%, respectively) (all p < 0.05).

Conclusion

The Amflow® device could be useful for rescuers in delivering SB ventilation with appropriate V _T and RR simultaneously in various critical situations, except for clinical cases that demand greater delivered V _T.

Comparing the neurologic outcomes of patients with out-of-hospital cardiac arrest according to prehospital advanced airway management method and transport time interval

OBJECTIVE

The incidences of prehospital advanced airway management by emergency medical technicians in South Korea are increasing; however, whether this procedure improves the survival outcomes of patients experiencing out-of-hospital cardiac arrest remains unclear. The present study aimed to investigate the association between prehospital advanced airway management and neurologic outcomes according to a transport time interval (TTI) using the Korean Cardiac Arrest Research Consortium database.

METHODS

We retrospectively analyzed the favorable database entries that were prospectively collected between October 2015 and December 2016. Patients aged 18 years or older who experienced cardiac arrest that was presumed to be of a medical etiology and that occurred prior to the arrival of emergency medical service personnel were included. The exposure variable was the type of prehospital airway management provided by emergency medical technicians. The primary endpoint was a favorable neurologic outcome.

RESULTS

Of 1,871 patients who experienced out-of-hospital cardiac arrest, 785 (42.0%), 121 (6.5%), and 965 (51.6%) were managed with bag-valve-mask ventilation, endotracheal intubation (ETI), and supraglottic airway (SGA) devices, respectively. SGAs and ETI provided no advantage in terms of favorable neurologic outcome in patients with TTIs ≥12 minutes (odds ratio [OR], 1.37; confidence interval [CI], 0.65-2.87 for SGAs; OR, 1.31; CI, 0.30-5.81 for ETI) or in patients with TTI <12 minutes (OR, 0.57; CI, 0.31-1.07 for SGAs; OR, 0.63; CI, 0.12-3.26 for ETI).

CONCLUSION

Neither the prehospital use of SGA nor administration of ETI was associated with superior neurologic outcomes compared with bag-valve-mask ventilation.

Baseline Cardiopulmonary Resuscitation Skill Performance of Nursing Students Is Improved After One Resuscitation Quality Improvement Skill Refresher

This article reports the results of baseline cardiopulmonary resuscitation (CPR) skills performance measurements from 467 nursing students. All participants had completed a CPR course. Baseline measurements were compared to performance after one 10-minute refresher training session on the Resuscitation Quality Improvement system. Significant improvements were made after the computer- and practice-based refresher. Findings suggest that staff developers should evaluate the use of audio and visual feedback devices to improve the quality of CPR provided by clinical staff.

Cardiopulmonary Resuscitation during COVID-19 Pandemic: Outcomes, Risks, and Protective Strategies for the Healthcare Workers and Ethical Considerations

The crisis caused by Coronavirus disease-2019 (COVID-19) pandemic has led us to safeguard ourselves and our colleagues against transmission of this highly contagious infection, while aiming for the same goals of care. In spite of the stringent measures adopted by affected countries, rising number of healthcare workers (HCWs) are getting infected, dwindling the scarce manpower at our disposal. In the pre-COVID-19 times, cardiopulmonary resuscitation (CPR) was offered unhesitantly to all patients, who had even a slim chance of achieving return of spontaneous circulation. In COVID-19 era, CPR, due to some components being high aerosol-generating procedures (AGPs), has become high-risk procedure for the HCWs. Instead of "Primum non nocere" (first do no harm), we are forced to change to "Primum non nocere ad te" (first do no harm to yourself). The challenge is therefore to provide best possible chance of survival to deserving patients, whose COVID-19 status might be unknown, without causing harm to the HCWs. In this review, we discuss the current data regarding infected HCWs, outcomes of inhospital and out-of-hospital cardiac arrests, components of CPR which are high-risk AGPs, how to safeguard the HCWs while offering CPR, and the ethical considerations when CPR is considered, in this COVID-19 era. We wish to emphasize here that there is NO EMERGENCY in a pandemic, and time must be made for donning appropriate PPE. We feel that clear policies need to be developed by the institutions to deliver CPR to correct population, in this challenging period. How to cite this article: Kulkarni AP, Singh Y, Garg H, Jha S. Cardiopulmonary Resuscitation during COVID-19 Pandemic: Outcomes, Risks, and Protective Strategies for the Healthcare Workers and Ethical Considerations. Indian J Crit Care Med 2020;24(9):868-872.

Fiberoptic-Guided and Blind Tracheal Intubation Through iLTS-D, Ambu® Auragain™, and I-Gel® Supraglottic Airway Devices: A Randomized Crossover Manikin Trial

BACKGROUND

The use of supraglottic airway devices (SADs) is becoming more widespread. However, there is little evidence to show which device is best in an emergent clinical scenario.

OBJECTIVE

We compared both fiberoptic-guided and blind tracheal intubation through the Intubating Laryngeal Tube Suction-Disposal (iLTS-D), the AuraGain™, and the i-gel® in an airway manikin.

METHODS

Thirty residents were included in a randomized trial to perform both fiberoptic-guided and blind tracheal intubation using the iLTS-D, the AuraGain, and the i-gel. The main endpoint was the total time taken to achieve successful fiberoptic intubation through the SAD. Additional endpoints included total time for blind intubation, SAD insertion time, tracheal tube insertion time, intubation success rate, fiberoptic view, and maneuvers performed to achieve tracheal intubation.

RESULTS

All participants performed fiberoptic intubation using all three SADs on the first attempt. The total time to fiberoptic tracheal intubation using the i-gel, AuraGain, and iLTS-D was 42 s, 56 s, and 56 s, respectively. The blind tracheal intubation success rate was 80% with the iLTS-D, 43% with the i-gel, and 0% with the AuraGain. The total time for blind tracheal intubation through the i-gel and the iLTS-D was 29 s and 40 s, respectively. Laryngeal view grades were significantly poorer with the iLTS-D compared to the other devices. The iLTS-D required significantly more maneuvers to achieve successful tracheal intubation.

CONCLUSIONS

In an airway manikin, the iLTS-D, AuraGain, and i-gel appear to be reliable devices for airway rescue and fiberoptic-guided tracheal intubation. The iLTS-D is recommended for blind tracheal intubation.