Quantitative Comparison of Ventilation Parameters of Different Approaches to Ventilator Splitting and Multiplexing.

CONTEXT: Amid the COVID-19 pandemic, this study delves into ventilator shortages, exploring simple split ventilation (SSV), simple differential ventilation (SDV), and differential multiventilation (DMV). The knowledge gap centers on understanding their performance and safety implications. HYPOTHESIS: Our hypothesis posits that SSV, SDV, and DMV offer solutions to the ventilator crisis. Rigorous testing was anticipated to unveil advantages and limitations, aiding the development of effective ventilation approaches. METHODS AND MODELS: Using a specialized test bed, SSV, SDV, and DMV were compared. Simulated lungs in a controlled setting facilitated measurements with sensors. Statistical analysis honed in on parameters like peak inspiratory pressure (PIP) and positive end-expiratory pressure. RESULTS: Setting target PIP at 15 cm H2O for lung 1 and 12.5 cm H2O for lung 2, SSV revealed a PIP of 15.67 ± 0.2 cm H2O for both lungs, with tidal volume (Vt) at 152.9 ± 9 mL. In SDV, lung 1 had a PIP of 25.69 ± 0.2 cm H2O, lung 2 at 24.73 ± 0.2 cm H2O, and Vts of 464.3 ± 0.9 mL and 453.1 ± 10 mL, respectively. DMV trials showed lung 1's PIP at 13.97 ± 0.06 cm H2O, lung 2 at 12.30 ± 0.04 cm H2O, with Vts of 125.8 ± 0.004 mL and 104.4 ± 0.003 mL, respectively. INTERPRETATION AND CONCLUSIONS: This study enriches understanding of ventilator sharing strategy, emphasizing the need for careful selection. DMV, offering individualization while maintaining circuit continuity, stands out. Findings lay the foundation for robust multiplexing strategies, enhancing ventilator management in crises.

Evaluation of a Rebreathing System for Use with Portable Mechanical Ventilators.

INTRODUCTION: Maximizing the capabilities of available lowflow oxygen is key to providing adequate oxygen to prevent/treat hypoxemia and conserve oxygen. We designed a closed-circuit system that allows rebreathing of gases while scrubbing carbon dioxide (CO2) in conjunction with portable mechanical ventilators in a bench model. METHODS: We evaluated the system using two portable mechanical ventilators currently deployed by the Department of Defense-Zoll 731 and AutoMedx SAVe II-over a range of ventilator settings and lung models, using 1 and 3L/min low-flow oxygen into a reservoir bag. We measured peak inspired oxygen concentration (FiO2), CO2-absorbent life, gas temperature and humidity, and the effect of airway suctioning and ventilator disconnection on FiO2 on ground and at altitude. RESULTS: FiO2 was =0.9 across all ventilator settings and altitudes using both oxygen flows. CO2-absorbent life was >7 hours. Airway humidity range was 87%-97%. Mean airway temperature was 25.4°C (SD 0.5°C). Ten-second suctioning reduced FiO2 22%-48%. Thirtysecond ventilator disconnect reduced FiO2 29%-63% depending on oxygen flow used. CONCLUSION: Use of a rebreathing system with mechanical ventilation has the potential for oxygen conservation but requires diligent monitoring of inspired FiO2 and CO2 to avoid negative consequences.

Risk factor evaluation of cuff pressure of >30 cmH2O to stop air leakage during mechanical ventilation: A prospective observational study.

AIM: The commonly recommended endotracheal tube cuff pressure is 20-30 cmH2O. However, some patients require a cuff pressure of >30 cmH2O to prevent air leakage. The study aims to determine the risk factors that contribute to the endotracheal tube cuff pressure of >30 cmH2O to prevent air leakage. DESIGN: A multi-centre prospective observational study. METHODS: Eligible patients undergoing mechanical ventilation in the intensive care unit of three hospitals between March 2020 and July 2022 were included. The endotracheal tube cuff pressure to prevent air leakage was determined using the minimal occlusive volume technique. The patient demographics and clinical information were collected. RESULTS: A total of 284 patients were included. Among these patients, 55 (19.37%) patients required a cuff pressure of >30 cmH2O to prevent air leakage. The multivariate logistic regression results revealed that the surgical operation (odds ratio [OR]: 8.485, 95% confidence interval [CI]: 1.066-67.525, p = 0.043) was inversely associated with the endotracheal tube cuff pressure of >30 cmH2O, while the oral intubation route (OR: 0.127, 95% CI: 0.022-0.750, p = 0.023) and cuff inner diameter minus tracheal area (OR: 0.949, 95% CI: 0.933-0.966, p < 0.001) were negatively associated with the endotracheal tube cuff pressure of >30 cmH2O. Therefore, a significant number of patients require an endotracheal tube cuff pressure of ＞30 cmH2O to prevent air leakage. Several factors, including the surgical operation, intubation route, and difference between the cuff inner diameter and tracheal area at the T3 vertebra, should be considered when determining the appropriate cuff pressure during mechanical ventilation.

Are instructors correctly gauging ventilation competence acquired by course attendees?

Achievement of adequate ventilation skills during training courses is mainly based on instructors' perception of attendees' capability to ventilate with correct rate and chest compression:ventilation ratio, while leading to chest raising, as evidence of adequate tidal volume. Accuracy in evaluating ventilation competence was assessed in 20 ACLS provider course attendees, by comparing course instructors' evaluation with measures from a ventilation feedback device. According to course instructors, all candidates acquired adequate ventilation competence. However, data from the feedback device indicated a ventilation not aligned with current guidelines, with higher tidal volume and lower rate (p < 0.01). Deploying quality ventilation during CPR is a skill whose acquisition starts with effective training. Therefore, course instructors' capability to accurately evaluate attendees' ventilation maneuvers is crucial.

Effect of different lung recruitment strategies and airway device on oscillatory mechanics in children under general anaesthesia.

BACKGROUND: Atelectasis has been reported in 68 to 100% of children undergoing general anaesthesia, a phenomenon that persists into the recovery period. Children receiving recruitment manoeuvres have less atelectasis and fewer episodes of oxygen desaturation during emergence. The optimal type of recruitment manoeuvre is unclear and may be influenced by the airway device chosen. OBJECTIVE: We aimed to investigate the different effects on lung mechanics as assessed by the forced oscillation technique (FOT) utilising different recruitment strategies: repeated inflations vs. one sustained inflation and different airway devices, a supraglottic airway device vs. a cuffed tracheal tube. DESIGN: Pragmatic enrolment with randomisation to the recruitment strategy. SETTING: We conducted this single-centre trial between February 2020 and March 2022. PARTICIPANTS: Seventy healthy patients (53 boys) aged between 2 and 16 years undergoing general anaesthesia were included. INTERVENTIONS: Forced oscillations (5 Hz) were superimposed on the ventilator waveform using a customised system connected to the anaesthesia machine. Pressure and flow were measured at the inlet of the airway device and used to compute respiratory system resistance and reactance. Measurements were taken before and after recruitment, and again at the end of surgery. MAIN OUTCOME MEASURES: The primary endpoint measured is the change in respiratory reactance. RESULTS: Statistical analysis (linear model with recruitment strategy and airway device as factors) did not show any significant difference in resistance and reactance between before and after recruitment. Baseline reactance was the strongest predictor for a change in reactance after recruitment: prerecruitment Xrs decreased by mean (standard error) of 0.25 (0.068) cmH 2 O s l -1 per  1 cmH 2 O -1  s l -1 increase in baseline Xrs ( P  < 0.001). After correcting for baseline reactance, the change in reactance after recruitment was significantly lower for sustained inflation compared with repeated inflation by mean (standard error) 0.25 (0.101) cmH 2 O ( P  = 0.0166). CONCLUSION: Although there was no significant difference between airway devices, this study demonstrated more effective recruitment via repeated inflations than sustained inflation in anaesthetised children. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12619001434189.

Humidification during Invasive and Non-Invasive Ventilation: A Starting Tool Kit for Correct Setting.

The humidification process of medical gases plays a crucial role in both invasive and non-invasive ventilation, aiming to mitigate the complications arising from bronchial dryness. While passive humidification systems (HME) and active humidification systems are prevalent in routine clinical practice, there is a pressing need for further evaluation of their significance. Additionally, there is often an incomplete understanding of the operational mechanisms of these devices. The current review explores the historical evolution of gas conditioning in clinical practice, from early prototypes to contemporary active and passive humidification systems. It also discusses the physiological principles underlying humidity regulation and provides practical guidance for optimizing humidification parameters in both invasive and non-invasive ventilation modalities. The aim of this review is to elucidate the intricate interplay between temperature, humidity, and patient comfort, emphasizing the importance of individualized approaches to gas conditioning.

Development and performance evaluation of a solenoid valve assisted low-cost ventilator on gas exchange and respiratory mechanics in a porcine model.

INTRODUCTION: During the COVID-19 pandemic, ventilator shortages necessitated the development of new, low-cost ventilator designs. The fundamental requirements of a ventilator include precise gas delivery, rapid adjustments, durability, and user-friendliness, often achieved through solenoid valves. However, few solenoid-valve assisted low-cost ventilator (LCV) designs have been published, and gas exchange evaluation during LCV testing is lacking. This study describes the development and performance evaluation of a solenoid-valve assisted low-cost ventilator (SV-LCV) in vitro and in vivo, focusing on gas exchange and respiratory mechanics. METHODS: The SV-LCV, a fully open ventilator device, was developed with comprehensive hardware and design documentation, utilizing solenoid valves for gas delivery regulation. Lung simulator testing calibrated tidal volumes at specified inspiratory and expiratory times, followed by in vivo testing in a porcine model to compare SV-LCV performance with a conventional ventilator. RESULTS: The SV-LCV closely matched the control ventilator's respiratory profile and gas exchange across all test cycles. Lung simulator testing revealed direct effects of compliance and resistance changes on peak pressures and tidal volumes, with no significant changes in respiratory rate. In vivo testing demonstrated comparable gas exchange parameters between SV-LCV and conventional ventilator across all cycles. Specifically, in cycle 1, the SV-LCV showed arterial blood gas (ABG) results of pH 7.54, PCO2 34.5 mmHg, and PO2 91.7 mmHg, compared to the control ventilator's ABG of pH 7.53, PCO2 37.1 mmHg, and PO2 134 mmHg. Cycle 2 exhibited ABG results of pH 7.53, PCO2 33.6 mmHg, and PO2 84.3 mmHg for SV-LCV, and pH 7.5, PCO2 34.2 mmHg, and PO2 93.5 mmHg for the control ventilator. Similarly, cycle 3 showed ABG results of pH 7.53, PCO2 32.1 mmHg, and PO2 127 mmHg for SV-LCV, and pH 7.5, PCO2 35.5 mmHg, and PO2 91.3 mmHg for the control ventilator. CONCLUSION: The SV-LCV provides similar gas exchange and respiratory mechanic profiles compared to a conventional ventilator. With a streamlined design and performance akin to commercially available ventilators, the SV-LCV presents a viable, readily available, and reliable short-term solution for overcoming ventilator supply shortages during crises.

Prediction and simulation of PEEP setting effects with machine learning models / Predicción y simulación de los efectos de la configuración de la PEEP con modelos de aprendizaje automático

Objective To establish a new machine learning-based method to adjust positive end-expiratory pressure (PEEP) using only already routinely measured data. Design Retrospective observational study. Setting Intensive care unit (ICU). Patients or participants 51811 mechanically ventilated patients in multiple ICUs in the USA (data from MIMIC-III and eICU databases). Interventions No interventions. Main variables of interest Success parameters of ventilation (arterial partial pressures of oxygen and carbon dioxide and respiratory system compliance). Results The multi-tasking neural network model performed significantly best for all target tasks in the primary test set. The model predicts arterial partial pressures of oxygen and carbon dioxide and respiratory system compliance about 45 min into the future with mean absolute percentage errors of about 21.7%, 10.0% and 15.8%, respectively. The proposed use of the model was demonstrated in case scenarios, where we simulated possible effects of PEEP adjustments for individual cases. Conclusions Our study implies that machine learning approach to PEEP titration is a promising new method which comes with no extra cost once the infrastructure is in place. Availability of databases with most recent ICU patient data is crucial for the refinement of prediction performance. (AU)

Objetivo Establecer un nuevo método basado en el aprendizaje automático para ajustar la presión positiva al final de la espiración (PEEP según sus siglas en inglés) utilizando únicamente datos ya obtenidos de forma rutinaria. Diseño Estudio retrospectivo de observación. Ámbito Unidad de cuidados intesivos (UCI) Pacientes o participantes 51811 pacientes ventilados mecánicamente en múltiples UCIs de EE.UU. (tomados de las bases de datos MIMIC-III y eICU). Intervenciones Sin intervenciones. Variables de interés principales Parametros de éxito de la ventilación (presiones parciales arteriales de oxígeno y dióxido de carbono y distensibilidad del sistema respiratorio). Resultados El modelo de red neuronal multitarea obtuvo los mejores resultados en todos los objetivos del conjunto de pruebas primario. El modelo predice las presiones parciales arteriales de oxígeno y dióxido de carbono así como la distensibilidad del sistema respiratorio con aproximadamente 45 minutos de anticipación, mostrando errores porcentuales absolutos medios de aproximadamente 21.7%, 10.0% y 15.8%, respectivamente. El uso propuesto del modelo se demostró en situaciones hipotéticas en las que se simularon los posibles efectos de los ajustes de PEEP para casos individuales. Conclusiones Nuestro estudio implica que el enfoque de aprendizaje automático para el ajuste de la PEEP es un método nuevo y prometedor que no supone ningún coste adicional una vez que se dispone de la infraestructura necesaria. La disponibilidad de bases de datos con información de pacientes de UCI más recientes es crucial para perfeccionar el rendimiento de la predicción. (AU)

A Tracheostomy Support Device to Reduce Tracheostomy-Related Pressure Injury.

BACKGROUND: Tracheostomies provide many advantages for the care of patients who are critically ill but may also result in complications, including tracheostomy-related pressure injuries. Research efforts into the prevention of these pressure injuries has resulted in specialized clinical care teams and pathways. These solutions are expensive and labor intensive, and fail to target the root cause of these injuries; namely, pressure at the device-skin interface. Here we measure that pressure directly and introduce a medical device, the tracheostomy support system, to reduce it. METHODS: This was a cross-sectional study of 21 subjects in the ICU, each with a tracheostomy tube connected to a ventilator. A force-sensing resistor was used to measure baseline pressures at the device-skin interface along the inferior flange. This pressure was then measured again with the use of the tracheostomy support system in the inactive and active states. Resultant pressures and demographics were compared. RESULTS: Fifteen male and 6 female subjects, with an average age of 47 ± 14 (mean ± SD) years, were included in this study. Average pressures at the tracheostomy-skin interface at baseline in these 21 ICU subjects were 273 ± 115 (mean ± SD) mm Hg. Average pressures were reduced by 59% (median 62%, maximum 98%) with the active tracheostomy support system to 115 ± 83 mm Hg (P < .001). All the subjects tolerated the tracheostomy support system without issue. CONCLUSIONS: Despite best clinical practice, pressure at the tracheostomy-skin interface can remain quite high. Here we provide measures of this pressure directly and show that a tracheostomy support system can be effective at minimizing that pressure.

The Effects of Inspiratory Flows, Inspiratory Pause, and Suction Catheter on Aerosol Drug Delivery with Vibrating Mesh Nebulizers During Mechanical Ventilation.

Background: Some experts recommend specific ventilator settings during nebulization for mechanically ventilated patients, such as inspiratory pause, high inspiratory to expiratory ratio, and so on. However, it is unclear whether those settings improve aerosol delivery. Thus, we aimed to evaluate the impact of ventilator settings on aerosol delivery during mechanical ventilation (MV). Methods: Salbutamol (5.0 mg/2.5 mL) was nebulized by a vibrating mesh nebulizer (VMN) in an adult MV model. VMN was placed at the inlet of humidifier and 15 cm away from the Y-piece of the inspiratory limb. Eight scenarios with different ventilator settings were compared with endotracheal tube (ETT) connecting 15 cm from the Y-piece, including tidal volumes of 6-8 mL/kg, respiratory rates of 12-20 breaths/min, inspiratory time of 1.0-2.5 seconds, inspiratory pause of 0-0.3 seconds, and bias flow of 3.5 L/min. In-line suction catheter was utilized in two scenarios. Delivered drug distal to the ETT was collected by a filter, and drug was assayed by an ultraviolet spectrophotometry (276 nm). Results: Compared to the use of inspiratory pause, the inhaled dose without inspiratory pause was either higher or similar across all ventilation settings. Inhaled dose was negatively correlated with inspiratory flow with VMN placed at 15 cm away from the Y-piece (rs = -0.68, p < 0.001) and at the inlet of humidifier (rs = -0.83, p < 0.001). The utilization of in-line suction catheter reduced inhaled dose, regardless of the ventilator settings and nebulizer placements. Conclusions: When VMN was placed at the inlet of humidifier, directly connecting the Y-piece to ETT without a suction catheter improved aerosol delivery. In this configuration, the inhaled dose increased as the inspiratory flow decreased, inspiratory pause had either no or a negative impact on aerosol delivery. The inhaled dose was greater with VMN placed at the inlet of humidifier than 15 cm away the Y-piece.

Design of a flow modulation device to facilitate individualized ventilation in a shared ventilator setup.

This study aims to resolve the unmet need for ventilator surge capacity by developing a prototype device that can alter patient-specific flow in a shared ventilator setup. The device is designed to deliver a predictable tidal volume (VT), requiring minimal additional monitoring and workload. The prototyped device was tested in an in vitro bench setup for its performance against the intended use and design criteria. The ventilation parameters: VT and airway pressures, and ventilation profiles: pressure, flow and volume were measured for different ventilator and device settings for a healthy and ARDS simulated lung pathology. We obtained VTs with a linear correlation with valve openings from 10 to 100% across set inspiratory pressures (IPs) of 20 to 30 cmH2O. Airway pressure varied with valve opening and lung elastance but did not exceed set IPs. Performance was consistent in both healthy and ARDS-simulated lung conditions. The ventilation profile diverged from traditional pressure-controlled profiles. We present the design a flow modulator to titrate VTs in a shared ventilator setup. Application of the flow modulator resulted in a characteristic flow profile that differs from pressure- or volume controlled ventilation. The development of the flow modulator enables further validation of the Individualized Shared Ventilation (ISV) technology with individualization of delivered VTs and the development of a clinical protocol facilitating its clinical use during a ventilator surge capacity problem.

Hyperventilation During Manual Ventilation Can Be Reduced Using a Novel Ventilator but Not With Education Interventions.

INTRODUCTION: Traumatic brain injury (TBI) is the leading cause of combat casualties in modern war with an estimated 20% of casualties experiencing head injury. Since the release of the Brain Trauma Foundation's Guidelines for the Management of Severe Traumatic Brain Injury in 1995, recommendations for management of TBI have included the avoidance of routine hyperventilation. However, both published and anecdotal data suggest that many patients with TBI are inappropriately ventilated during transport, thereby increasing the risk of morbidity and mortality from secondary brain injury. MATERIALS AND METHODS: Enlisted Air Force personnel with prior emergency medical technician training completing a 3-week trauma course were evaluated on their ability to provide manual ventilation. Participants provided manual ventilation using either an in-situ endotracheal tube (ETT) or standard face mask on a standardized simulated patient manikin with TBI on the first and last days of the course. Manual ventilation was provided via a standard manual ventilator and a novel manual ventilator designed to limit tidal volume (VT) and respiratory rate (RR). Participants were given didactic and hands-on training on the third day of the course. Half of the participants were given simulator feedback during the hands-on training. All students provided 2 minutes of manual ventilation with each respirator. Data were collected on the breath-to-breath RR, VT, and peak airway pressures generated by the participant for each trial and were averaged for each trial. A minute ventilation (MV) was then derived from the calculated RR and VT. RESULTS: One hundred fifty-six personnel in the trauma course were evaluated in this study. Significant differences were found in the participant's performance with manual ventilation with the novel compared to the traditional ventilator. Before training, MV with the novel ventilator was less than with the traditional ventilator by 2.1 ± 0.4 L/min (P = .0003) and 1.6 ± 0.5 L/min (P = .0489) via ETT and face mask, respectively. This effect persisted after training with a difference between the devices of 1.8 ± 0.4 L/min (P = .0069) via ETT. Both traditional education interventions (didactics with hands-on training) and simulator-based feedback did not make a significant difference in participant's performance in delivering MV. CONCLUSIONS: The use of a novel ventilator that limits RR and VT may be useful in preventing hyperventilation in TBI patients. Didactic education and simulator-based feedback training may not have significant impact on improving ventilation practices in prehospital providers.

Effects of closed loop ventilation on ventilator settings, patient outcomes and ICU staff workloads - a systematic review.

BACKGROUND: Lung protective ventilation is considered standard of care in the intensive care unit. However, modifying the ventilator settings can be challenging and is time consuming. Closed loop modes of ventilation are increasingly attractive for use in critically ill patients. With closed loop ventilation, settings that are typically managed by the ICU professionals are under control of the ventilator's algorithms. OBJECTIVES: To describe the effectiveness, safety, efficacy and workload with currently available closed loop ventilation modes. DESIGN: Systematic review of randomised clinical trials. DATA SOURCES: A comprehensive systematic search in PubMed, Embase and the Cochrane Central register of Controlled Trials search was performed in January 2023. ELIGIBILITY CRITERIA: Randomised clinical trials that compared closed loop ventilation with conventional ventilation modes and reported on effectiveness, safety, efficacy or workload. RESULTS: The search identified 51 studies that met the inclusion criteria. Closed loop ventilation, when compared with conventional ventilation, demonstrates enhanced management of crucial ventilator variables and parameters essential for lung protection across diverse patient cohorts. Adverse events were seldom reported. Several studies indicate potential improvements in patient outcomes with closed loop ventilation; however, it is worth noting that these studies might have been underpowered to conclusively demonstrate such benefits. Closed loop ventilation resulted in a reduction of various aspects associated with the workload of ICU professionals but there have been no studies that studied workload in sufficient detail. CONCLUSIONS: Closed loop ventilation modes are at least as effective in choosing correct ventilator settings as ventilation performed by ICU professionals and have the potential to reduce the workload related to ventilation. Nevertheless, there is a lack of sufficient research to comprehensively assess the overall impact of these modes on patient outcomes, and on the workload of ICU staff.

Physiologic Effects of Reconnection to the Ventilator for 1 Hour Following a Successful Spontaneous Breathing Trial.

BACKGROUND: Reconnection to the ventilator for 1 h following a successful spontaneous breathing trial (SBT) may reduce reintubation rates compared with direct extubation. However, the physiologic mechanisms leading to this effect are unclear. RESEARCH QUESTION: Does reconnection to the ventilator for 1 h reverse alveolar derecruitment induced by SBT, and is alveolar derecruitment more pronounced with a T-piece than with pressure-support ventilation (PSV)? STUDY DESIGN AND METHODS: This is an ancillary study of a randomized clinical trial comparing SBT performed with a T-piece or with PSV. Alveolar recruitment was assessed by using measurement of end-expiratory lung volume (EELV). RESULTS: Of the 25 patients analyzed following successful SBT, 11 underwent SBT with a T-piece and 14 with PSV. At the end of the SBT, EELV decreased by -30% (95% CI, -37 to -23) compared with baseline prior to the SBT. This reduction was greater with a T-piece than with PSV: -43% (95% CI, -51 to -35) vs -20% (95% CI, -26 to -13); P < .001. Following reconnection to the ventilator for 1 h, EELV accounted for 96% (95% CI, 92 to 101) of baseline EELV and did not significantly differ from prior to the SBT (P = .104). Following 10 min of reconnection to the ventilator, EELV wasted at the end of the SBT was completely recovered using PSV (P = .574), whereas it remained lower than prior to the SBT using a T-piece (P = .010). INTERPRETATION: Significant alveolar derecruitment was observed at the end of an SBT and was markedly more pronounced with a T-piece than with PSV. Reconnection to the ventilator for 1 h allowed complete recovery of alveolar derecruitment. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT04227639; URL: www. CLINICALTRIALS: gov.

Comparison of hemodynamic effects of chest compression delivered via machine or human in asphyxiated piglets.

BACKGROUND: High-quality chest compressions (CC) are an important factor of neonatal resuscitation. Mechanical CC devices may provide superior CC delivery and improve resuscitation outcomes. We aimed to compare the hemodynamic effects of CC delivered by machine and human using a neonatal piglet model. METHODS: Twelve asphyxiated piglets were randomized to receive CC during resuscitation using an automated mechanical CC device ("machine") or the two-thumb encircling technique ("human"). CC was superimposed with sustained inflations. RESULTS: Twelve newborn piglets (age 0-3 days, weight 2.12 ± 0.17 kg) were included in the study. Machine-delivered CC resulted in an increase in stroke volume, and minimum and maximum rate of left ventricle pressure change (dp/dtmin and dp/dtmax) compared to human-delivered CC. CONCLUSIONS: During machine-delivered CC, stroke volume and left ventricular contractility were significantly improved. Mechanical CC devices may provide improved cardiopulmonary resuscitation outcomes in neonatal cardiac arrest induced by asphyxia. IMPACT: Machine chest compression leads to changes in hemodynamic parameters during resuscitation of asphyxiated neonatal piglets, namely greater stroke volume and left ventricular contractility, compared with standard two-thumb compression technique. Mechanical chest compression devices may provide improved cardiopulmonary resuscitation outcomes in neonatal and pediatric asphyxia-induced cardiac arrest.

Evaluation of an automatized AMBU ESSI-1 INC designed at the Instituto Nacional de Cardiología Ignacio Chávez.

OBJECTIVE: The objectives of this study were to evaluate an automated device for ventilatory support based on AMBU manufactured in March 2020. METHODS: The ESSI-1 INC was evaluated through pulmonary mechanics and physiology parameters through compensatory spirometer tests (TISSOTs), and an artificial lung Model5600i Dual Adult PNEU VIEW SYSTEM; it was also compared to the anesthetic ventilatory support equipment (AEONMED 7500) in porcine models, measuring ventilatory, hemodynamic and gasometric parameters. RESULTS: This equipment (ESSI-1 INC) was successfully tested by mechanical and biological models, such as pigs in which its performance was evaluated in terms of variability of tidal volume, ventilation frequency, and I/E relationship versus the manual performance of two medical interns. All the results turned out as expected and were satisfactory. CONCLUSIONS: It is safe and effective equipment and should be tested and used in diverse clinical conditions to standardize the ventilatory safety and care of patients who require it.

OBJETIVO: Evaluar un dispositivo automatizado para la asistencia ventilatoria basado en un AMBU manufacturado en Marzo del 2020. MÉTODOS: El ESSI-1 INC fue evaluado por medio de parámetros fisiológicos y mecánica pulmonar a través de pruebas de espirómetro compensatorios (TISSOT); pulmón artificial (Modelo 5600i Dual Adult PNEU VIEW SYSTEM); así como su desempeño comparado a la máquina de anestesia (AEONMED 7500) en modelos porcinos, midiendo criterios ventilatorios, hemodinámicos y gasométricos. RESULTADOS: Este equipo (ESSI-1 INC) fue exitosamente probado por modelos mecánicos y biológicos, tales como cerdos donde su desempeño fue evaluado en términos de la variabilidad del volumen tidal, frecuencia ventilatoria, y relación I/E versus el desempeño manual de dos médicos. Todos los resultados finalizaron como se esperaba de forma satisfactoria. CONCLUSIONES: Es un equipo seguro y efectivo, el cual debería ser probado y usado en distintas condiciones clínicas para estandarizar la seguridad ventilatoria y cuidado de pacientes que lo requieran.

COVID-19 e o ciclo gravídico-puerperal: uma revisão narrativa / COVID-19 and the pregnancy cycle: a narrative review

Até este momento da pandemia de COVID-19, embora as gestantes não tenham maior risco de se infectar do que a população geral, elas têm maiores riscos de desenvolver formas graves e demandar cuidados de UTI e ventilação invasiva, so- bretudo aquelas que apresentam comorbidades. No Brasil, a mortalidade materna por COVID-19 está entre as mais elevadas do mundo. A transmissão vertical do SARS-CoV-2 parece ser um evento raro, e até o momento não se observou aumento da ocorrência de abortos e malformações. Entretanto, a COVID-19 está associada a elevadas taxas de prematuridade, baixo peso ao nascer e admissão em UTI neona- tal. Em adaptação a esse novo cenário, são indicados cuidados especiais durante o ciclo gravídico-puerperal, sendo útil destacar: o espaço crescente da telemedicina no pré-natal; a não obrigatoriedade da realização de cesariana em caso de gestan- te infectada no momento do parto e a liberação da amamentação pelas puérperas com COVID-19.