Using machine learning for predicting intensive care unit resource use during the COVID-19 pandemic in Denmark.

The COVID-19 pandemic has put massive strains on hospitals, and tools to guide hospital planners in resource allocation during the ebbs and flows of the pandemic are urgently needed. We investigate whether machine learning (ML) can be used for predictions of intensive care requirements a fixed number of days into the future. Retrospective design where health Records from 42,526 SARS-CoV-2 positive patients in Denmark was extracted. Random Forest (RF) models were trained to predict risk of ICU admission and use of mechanical ventilation after n days (n = 1, 2, …, 15). An extended analysis was provided for n = 5 and n = 10. Models predicted n-day risk of ICU admission with an area under the receiver operator characteristic curve (ROC-AUC) between 0.981 and 0.995, and n-day risk of use of ventilation with an ROC-AUC between 0.982 and 0.997. The corresponding n-day forecasting models predicted the needed ICU capacity with a coefficient of determination (R2) between 0.334 and 0.989 and use of ventilation with an R2 between 0.446 and 0.973. The forecasting models performed worst, when forecasting many days into the future (for large n). For n = 5, ICU capacity was predicted with ROC-AUC 0.990 and R2 0.928, and use of ventilator was predicted with ROC-AUC 0.994 and R2 0.854. Random Forest-based modelling can be used for accurate n-day forecasting predictions of ICU resource requirements, when n is not too large.

The critical importance of mask seals on respirator performance: An analytical and simulation approach.

Filtering facepiece respirators (FFRs) and medical masks are widely used to reduce the inhalation exposure of airborne particulates and biohazardous aerosols. Their protective capacity largely depends on the fraction of these that are filtered from the incoming air volume. While the performance and physics of different filter materials have been the topic of intensive study, less well understood are the effects of mask sealing. To address this, we introduce an approach to calculate the influence of face-seal leakage on filtration ratio and fit factor based on an analytical model and a finite element method (FEM) model, both of which take into account time-dependent human respiration velocities. Using these, we calculate the filtration ratio and fit factor for a range of ventilation resistance values relevant to filter materials, 500-2500 Pa∙s∙m-1, where the filtration ratio and fit factor are calculated as a function of the mask gap dimensions, with good agreement between analytical and numerical models. The results show that the filtration ratio and fit factor are decrease markedly with even small increases in gap area. We also calculate particle filtration rates for N95 FFRs with various ventilation resistances and two commercial FFRs exemplars. Taken together, this work underscores the critical importance of forming a tight seal around the face as a factor in mask performance, where our straightforward analytical model can be readily applied to obtain estimates of mask performance.

Preference of neuromuscular patients regarding equipment for daytime mouthpiece ventilation: A randomized crossover study.

BACKGROUND: Patients with neuromuscular disorders (NMDs) are likely to develop respiratory failure which requires noninvasive ventilation (NIV). Ventilation via a mouthpiece (MPV) is an option to offer daytime NIV. OBJECTIVES: To determine the preferred equipment for MPV by patients with NMDs. METHODS: Two MPV equipment sets were compared in 20 patients with NMDs. Set 1, consisted of a non-dedicated ventilator for MPV (PB560, Covidien) with a plastic angled mouthpiece. Set 2, consisted of a dedicated MPV ventilator (Trilogy 100, Philips Respironics) without backup rate and kiss trigger combined with a silicone straw mouthpiece. The Borg dyspnea score, ventilator free time, transcutaneous oxygen saturation (SpO2) and carbon dioxide tension (TcCO2 ) were recorded with and without MPV. Patient perception was assessed by a 17-items list. RESULTS: Carbon dioxide tension measurements and total perception score were not different between the two MPV sets. Dyspnea score was lower with the non-dedicated versus dedicated equipment, 1 (0.5) versus 3 (1-6), P < 0.01. All patients with a ventilator free time lower than 6 hours preferred a set backup rate rather than a kiss trigger. Sixty five percent of patients preferred the commercial arm support and 55% preferred the plastic angled mouthpiece. CONCLUSIONS: Dedicated and non-dedicated MPV equipment are deemed effective and comfortable. Individualization of arm support and mouthpiece is advised to ensure success of MPV. A ventilator free time lower than 6 hours seems to be a useful indicator to a priori set a backup rate rather than a rate at zero associated to the kiss trigger.

The addition of a humidifier device to a circuit and its impact on home ventilator performance: a bench study.

INTRODUCTION AND OBJECTIVES: Humidification and non-invasive ventilation are frequently used together, despite the lack of precise recommendations regarding this practice. We aimed to analyse the impact of active external and built-in humidifiers on the performance of home ventilators, focusing on their pressurization efficacy and their behaviour under different inspiratory efforts. METHODS: We designed a bench study of a lung simulator programmed to emulate mechanical conditions similar to those experienced by real respiratory patients and to simulate three different levels of inspiratory effort: five different commonly used home NIV devices and active humidifiers attached to the latter (internal or "built-in") or to the circuit (external). To test ventilator pressurization under different humidification and effort settings, pressure-time products in the first 300ms and 500ms of the respiratory cycle were calculated in the 45 situations simulated. Inferential statistical analysis was performed. RESULTS: A significant reduction of PTP 300 and PTP 500 was observed with the external humidifier in three of the devices. The same pattern was noted for another device with an internal humidifier, and only one device showed no significant changes. This impact on pressurization was commonly higher under high inspiratory effort. CONCLUSIONS: These results indicate the need to monitor pressure changes in the use of external humidification devices in some home NIV ventilators.

First responder communication in CBRN environments: FIRCOM-CBRN study.

INTRODUCTION: Recent terror attacks and assassinations involving highly toxic chemical weapons have stressed the importance of sufficient respiratory protection of medical first responders and receivers. As full-face respirators cause perceptual-motor impairment, they not only impair vision but also significantly reduce speech intelligibility. The recent introduction of electronic voice projection units (VPUs), attached to a respirator, may improve communication while wearing personal respiratory protection. OBJECTIVE: To determine the influence of currently used respirators and VPUs on medical communication and speech intelligibility. METHODS: 37 trauma anaesthetists carried out an evaluation exercise of six different respirators and VPUs including one control. Participants had to listen to audio clips of a variety of sentences dealing with scenarios of emergency triage and medical history taking. RESULTS: In the questionnaire, operators stated that speech intelligibility of the Avon C50 respirator scored the highest (mean 3.9, ±SD 1.0) and that the Respirex Powered Respiratory Protective Suit (PRPS) NHS-suit scored lowest (1.6, 0.9). Regarding loudness the C50 plus the Avon VPU scored highest (4.1, 0.7), followed by the Draeger FPS-7000-com-plus (3.4, 1.0) and the Respirex PRPS NHS-suit scored lowest (2.3, 0.8). CONCLUSIONS: We found that the Avon C50 is the preferred model among the tested respirators. In our model, electronic voice projection modules improved loudness but not speech intelligibility. The Respirex PRPS NHS-suit was rated significantly less favourably in respect of medical communication and speech intelligibility.

Temporal Changes in Ventilator Settings in Patients With Uninjured Lungs: A Systematic Review.

In patients with uninjured lungs, increasing evidence indicates that tidal volume (VT) reduction improves outcomes in the intensive care unit (ICU) and in the operating room (OR). However, the degree to which this evidence has translated to clinical changes in ventilator settings for patients with uninjured lungs is unknown. To clarify whether ventilator settings have changed, we searched MEDLINE, Cochrane Central Register of Controlled Trials, and Web of Science for publications on invasive ventilation in ICUs or ORs, excluding those on patients <18 years of age or those with >25% of patients with acute respiratory distress syndrome (ARDS). Our primary end point was temporal change in VT over time. Secondary end points were changes in maximum airway pressure, mean airway pressure, positive end-expiratory pressure, inspiratory oxygen fraction, development of ARDS (ICU studies only), and postoperative pulmonary complications (OR studies only) determined using correlation analysis and linear regression. We identified 96 ICU and 96 OR studies comprising 130,316 patients from 1975 to 2014 and observed that in the ICU, VT size decreased annually by 0.16 mL/kg (-0.19 to -0.12 mL/kg) (P < .001), while positive end-expiratory pressure increased by an average of 0.1 mbar/y (0.02-0.17 mbar/y) (P = .017). In the OR, VT size decreased by 0.09 mL/kg per year (-0.14 to -0.04 mL/kg per year) (P < .001). The change in VTs leveled off in 1995. Other intraoperative ventilator settings did not change in the study period. Incidences of ARDS (ICU studies) and postoperative pulmonary complications (OR studies) also did not change over time. We found that, during a 39-year period, from 1975 to 2014, VTs in clinical studies on mechanical ventilation have decreased significantly in the ICU and in the OR.

Estado de la ventilación mecánica en la Comunidad de Madrid / Home mechanical ventilation in Madrid area

Introducción. En la actualidad, la ventilación mecánica domiciliaria (VMD) se ha convertido en una terapia de uso habitual. La tasa de uso en España es desconocida, por lo que se ha realizado una encuesta en todos los hospitales de la Comunidad de Madrid (CAM) adscritos al Sistema Nacional de Salud para recoger los datos de los pacientes tratados con VMD en octubre y noviembre de 2018. Material y métodos. Se distribuyó una encuesta on-line entre todos los hospitales de la CAM de los grupos funcionales homogéneos (GFH) 1, 2 y 3 pertenecientes al Sistema Nacional de Salud. La encuesta constaba de 50 preguntas y se solicitó que se respondiera a las preguntas con datos reales, no estimados. Resultados. La encuesta la contestaron 18 hospitales, aunque todas las preguntas del cuestionario solo fueron contestadas por 10. La tasa de uso de VMD en la CAM fue de 74/100.000 habitantes. La edad media de los pacientes en VMD era de 69 años (63-76) y el 56% eran varones. La patología que más frecuentemente justificaba la VMD fue el síndrome de obesidad hipoventilación 41% (25-70). Se encontró mucha variabilidad intercentro tanto en la tasa de VMD como en la patología que justificaba la indicación. Todos los hospitales menos 2 disponían de consulta monográfica de VMD. La adaptación se realizaba fundamentalmente en hospitalización (33%) u hospital de día (33%). Se necesita más tiempo, más personal y mejores recursos técnicos para realizar una adecuada monitorización. La relación con las empresas suministradoras de terapias es buena

Introduction. Nowadays home mechanical ventilation (HMV) is a normal use in pneumology. Rate of use in Spain is unknown. We have developed a survey in all Public Madrid Area Hospitals to keep data about HMV patients between 2018 october and november. Methods. We sent an on-line survey to all Public Madrid Area Hospitals with 50 questions about HMV uses. We asked for real data answers, trying to not estimate answers. Results. The survey was answered by 18 hospitals, although all survey questions were answered by 10 hospitals. Rate of use of HMV in Madrid Area was 74/100.000. Mean age was 69 (63-76) years and 56% were males. The most frequent pathology that justified HMV was obesity hipoventilation syndrome 41% (25-70). We found a high variability interhospital in HMV rate and in the pathology that justified it. All the hospitals instead 2 of them had a monography HMV consult. HMV adaptation was done majority in hospitalization (33%) and in day hospital (33%). It is necessary more time, more people and better devices to achieve a proper monitoring. The relationship with the therapy providers is good

Respiratory variation in peripheral arterial blood flow peak velocity to predict fluid responsiveness in mechanically ventilated patients: a systematic review and meta-analysis.

BACKGROUND: Fluid overloading is detrimental to organ function and results in a poor prognosis. It is necessary to evaluate fluid responsiveness before fluid loading. We performed a systematic meta-analysis to evaluate the diagnostic value of the respiratory variation in peripheral arterial blood flow peak velocity (△Vpeak PA) in predicting fluid responsiveness in mechanically ventilated patients. METHODS: PubMed, Embase and The Cochrane Library databases were searched for studies that used △Vpeak PA to predict fluid responsiveness in mechanically ventilated patients. We calculated the pooled values of sensitivity, specificity and the area of the summary receiver operating characteristic curve by Meta-Disc 14.0 software. RESULTS: Nine studies with a total of 402 patients were included. Two low quality studies were deleted in further analysis. Moreover, because of different locations of peripheral artery, the rest included studies were divided into brachial site group and carotid site group for meta-analysis individually. The pooled sensitivity, specificity and area under curve were 0.85 (95% confidence interval (CI) 0.77-0.92), 0.86 (95% CI 0.77-0.92) and 0.9268 in carotid site group. The pooled sensitivity, specificity and area under curve were 0.72 (95% CI 0.60-0.81), 0.85 (95% CI 0.74-0.93) and 0.8587 in brachial site group. CONCLUSIONS: △Vpeak of carotid and brachial artery had a diagnostic value in predicting fluid responsiveness respectively. Moreover, △Vpeak of carotid artery had more value than brachial artery in predicting fluid responsiveness. However, there was some clinical heterogeneity; therefore, further studies are needed to confirm diagnostic accuracy.

Chest physiotherapy with early mobilization may improve extubation outcome in critically ill patients in the intensive care units.

BACKGROUND: Extubation failure can lead to a longer intensive care unit (ICU) stay, higher mortality rate, and higher risk of requiring tracheostomy. Chest physiotherapy (CPT) can help patients in reducing the accumulation of airway secretion, preventing collapsed lung, improving lung compliance, and reducing comorbidities. Much research has investigated the correlation between CPT and respiratory system clearance. However, few studies have investigated the correlation between CPT and failed ventilator extubation. Therefore, this study aimed to investigate the use of CPT for reducing the rate of failed removal from mechanical ventilators. METHODS: This study was an intervention study with mechanical control. Subjects were divided into two groups. The control group, which received routine nursing chest care, was selected from a retrospective chart review. The intervention group was prospectively taken into the chest physiotherapy program. The chest physiotherapy treatment protocol consisted of inspiratory muscle training, manual hyperinflation, chest wall mobilization, secretion removal, cough function training, and early mobilization. RESULTS: A total of 439 subjects were enrolled in the intervention and control groups, with a mean age of 69 years. APACHE II score (P = .09) and GCS scores (P = .54) were similar between the two groups. Compared to the control group, patients in the intervention group had a significantly lower reintubation rate (8% vs 16%; P = .01). CONCLUSIONS: The results indicate that intensive chest physiotherapy could decrease extubation failure in mechanically ventilated patients in the ICU. In addition, chest physiotherapy could also significantly improve the rapid shallow breathing index score.

Improved lung recruitment and oxygenation during mandatory ventilation with a new expiratory ventilation assistance device: A controlled interventional trial in healthy pigs.

BACKGROUND: In contrast to conventional mandatory ventilation, a new ventilation mode, expiratory ventilation assistance (EVA), linearises the expiratory tracheal pressure decline. OBJECTIVE: We hypothesised that due to a recruiting effect, linearised expiration oxygenates better than volume controlled ventilation (VCV). We compared the EVA with VCV mode with regard to gas exchange, ventilation volumes and pressures and lung aeration in a model of peri-operative mandatory ventilation in healthy pigs. DESIGN: Controlled interventional trial. SETTING: Animal operating facility at a university medical centre. ANIMALS: A total of 16 German Landrace hybrid pigs. INTERVENTION: The lungs of anaesthetised pigs were ventilated with the EVA mode (n=9) or VCV (control, n=7) for 5 h with positive end-expiratory pressure of 5 cmH2O and tidal volume of 8 ml kg. The respiratory rate was adjusted for a target end-tidal CO2 of 4.7 to 6 kPa. MAIN OUTCOME MEASURES: Tracheal pressure, minute volume and arterial blood gases were recorded repeatedly. Computed thoracic tomography was performed to quantify the percentages of normally and poorly aerated lung tissue. RESULTS: Two animals in the EVA group were excluded due to unstable ventilation (n=1) or unstable FiO2 delivery (n=1). Mean tracheal pressure and PaO2 were higher in the EVA group compared with control (mean tracheal pressure: 11.6 ±â€Š0.4 versus 9.0 ±â€Š0.3 cmH2O, P < 0.001 and PaO2: 19.2 ±â€Š0.7 versus 17.5 ±â€Š0.4 kPa, P = 0.002) with comparable peak inspiratory tracheal pressure (18.3 ±â€Š0.9 versus 18.0 ±â€Š1.2 cmH2O, P > 0.99). Minute volume was lower in the EVA group compared with control (5.5 ±â€Š0.2 versus 7.0 ±â€Š1.0 l min, P = 0.02) with normoventilation in both groups (PaCO2 5.4 ±â€Š0.3 versus 5.5 ±â€Š0.3 kPa, P > 0.99). In the EVA group, the percentage of normally aerated lung tissue was higher (81.0 ±â€Š3.6 versus 75.8 ±â€Š3.0%, P = 0.017) and of poorly aerated lung tissue lower (9.5 ±â€Š3.3 versus 15.7 ±â€Š3.5%, P = 0.002) compared with control. CONCLUSION: EVA ventilation improves lung aeration via elevated mean tracheal pressure and consequently improves arterial oxygenation at unaltered positive end-expiratory pressure (PEEP) and peak inspiratory pressure (PIP). These findings suggest the EVA mode is a new approach for protective lung ventilation.

Patient factors and outcomes associated with the withdrawal or withholding of life-sustaining therapies in mechanically ventilated brain-injured patients: An observational multicentre study.

BACKGROUND: Knowledge of the factors associated with the decision to withdraw or withhold life support (WWLS) in brain-injured patients is limited. However, most deaths in these patients may involve such a decision. OBJECTIVES: To identify factors associated with the decision to WWLS in brain-injured patients requiring mechanical ventilation who survive the first 24 h in the ICU, and to analyse the outcomes and time to death. DESIGN: A retrospective observational multicentre study. SETTINGS: Twenty French ICUs in 18 university hospitals. PATIENTS: A total of 793 mechanically ventilated brain-injured adult patients. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Decision to WWLS within 3 months of ICU admission, and death or Glasgow Outcome Scale (GOS) score at day 90. RESULTS: A decision to WWLS was made in 171 patients (22%), of whom 89% were dead at day 90. Out of the 247 deaths recorded at day 90, 153 (62%) were observed after a decision to WWLS. The median time between admission and death when a decision to WWLS was made was 10 (5 to 20) days vs. 10 (5 to 26) days when no end-of-life decision was made (P < 0.924). Among the 18 patients with a decision to WWLS who were still alive at day 90, three patients (2%) had a GOS score of 2, nine patients (5%) had a GOS score of 3 and five patients (3%) a GOS score of 4. Older age, presence of one nonreactive and dilated pupil, Glasgow Coma Scale less than 7, barbiturate use, acute respiratory distress syndrome and worsening lesions on computed tomography scans were each independently associated with decisions to WWLS. CONCLUSION: Using a nationwide cohort of brain-injured patients, we observed a high proportion of deaths associated with an end-of-life decision. Older age and several disease severity factors were associated with the decision to WWLS.

Dexmedetomidine Impairs Diaphragm Function and Increases Oxidative Stress but Does Not Aggravate Diaphragmatic Atrophy in Mechanically Ventilated Rats.

BACKGROUND: Anesthetics in ventilated patients are critical as any cofactor hampering diaphragmatic function may have a negative impact on the weaning progress and therefore on patients' mortality. Dexmedetomidine may display antioxidant and antiproteolytic properties, but it also reduced glucose uptake by the muscle, which may impair diaphragm force production. This study tested the hypothesis that dexmedetomidine could inhibit ventilator-induced diaphragmatic dysfunction. METHODS: Twenty-four rats were separated into three groups (n = 8/group). Two groups were mechanically ventilated during either dexmedetomidine or pentobarbital exposure for 24 h, referred to as interventional groups. A third group of directly euthanized rats served as control. Force generation, fiber dimensions, proteolysis markers, protein oxidation and lipid peroxidation, calcium homeostasis markers, and glucose transporter-4 (Glut-4) translocation were measured in the diaphragm. RESULTS: Diaphragm force, corrected for cross-sectional area, was significantly decreased in both interventional groups compared to controls and was significantly lower with dexmedetomidine compared to pentobarbital (e.g., 100 Hz: -18%, P < 0.0001). In contrast to pentobarbital, dexmedetomidine did not lead to diaphragmatic atrophy, but it induced more protein oxidation (200% vs. 73% in pentobarbital, P = 0.0015), induced less upregulation of muscle atrophy F-box (149% vs. 374% in pentobarbital, P < 0.001) and impaired Glut-4 translocation (-73%, P < 0.0005). It activated autophagy, the calcium-dependent proteases, and caused lipid peroxidation similarly to pentobarbital. CONCLUSIONS: Twenty-four hours of mechanical ventilation during dexmedetomidine sedation led to a worsening of ventilation-induced diaphragm dysfunction, possibly through impaired Glut-4 translocation. Although dexmedetomidine prevented diaphragmatic fiber atrophy, it did not inhibit oxidative stress and activation of the proteolytic pathways.

The Anesthesia Workstation: Quo Vadis?

Ensuring adequate ventilation and oxygenation and delivering inhaled anesthetic agent to the patient remain core responsibilities of the anesthesia provider during general anesthesia. Because of the emphasis placed on physiology, pharmacology, clinical sciences, and administrative duties, the stellar anesthesia workstation technology may be underutilized by the anesthesia community. Target-controlled O2 and agent delivery and automated end-expired CO2 control have entered the clinical arena, with only cost, luddism, and administrative hurdles preventing their more widespread use. This narrative review will explain technological aspects of existing and recently introduced anesthesia workstations. Concepts rather than particular anesthesia machines will be addressed, but examples will mostly pertain to the more recently introduced workstations. The anesthesia workstation consists of a ventilator, a carrier gas and agent delivery system, a scavenging system, and monitors. Mainly, the circle breathing circuit configuration, ventilator, and carrier gas and agent delivery technology are discussed. Occasionally, technical details are provided to give the reader a taste of the modern technology.

Are we fully utilizing the functionalities of modern operating room ventilators?

PURPOSE OF REVIEW: The modern operating room ventilators have become very sophisticated and many of their features are comparable with those of an ICU ventilator. To fully utilize the functionality of modern operating room ventilators, it is important for clinicians to understand in depth the working principle of these ventilators and their functionalities. RECENT FINDINGS: Piston ventilators have the advantages of delivering accurate tidal volume and certain flow compensation functions. Turbine ventilators have great ability of flow compensation. Ventilation modes are mainly volume-based or pressure-based. Pressure-based ventilation modes provide better leak compensation than volume-based. The integration of advanced flow generation systems and ventilation modes of the modern operating room ventilators enables clinicians to provide both invasive and noninvasive ventilation in perioperative settings. Ventilator waveforms can be used for intraoperative neuromonitoring during cervical spine surgery. SUMMARY: The increase in number of new features of modern operating room ventilators clearly creates the opportunity for clinicians to optimize ventilatory care. However, improving the quality of ventilator care relies on a complete understanding and correct use of these new features. VIDEO ABSTRACT: http://links.lww.com/COAN/A47.

Neuromuscular disorders and chronic ventilation.

Morbidity and mortality have decreased in patients with neuromuscular disease due to implementation of therapies to augment cough and improve ventilation. Infants with progressive neuromuscular disease will eventually develop respiratory complications as a result of muscle weakness and their inability to compensate during periods of increased respiratory loads. The finding of nocturnal hypercapnia is often the trigger for initiating non-invasive ventilation and studies have shown that its use not only may improve sleep-disordered breathing, but also that it may have an effect on daytime function, symptoms related to hypercapnia, and partial pressure of CO2. It is important to understand the respiratory physiology of this population and to understand the benefits and limitations of assisted ventilation.

Automatic detection of ventilatory modes during invasive mechanical ventilation.

BACKGROUND: Expert systems can help alleviate problems related to the shortage of human resources in critical care, offering expert advice in complex situations. Expert systems use contextual information to provide advice to staff. In mechanical ventilation, it is crucial for an expert system to be able to determine the ventilatory mode in use. Different manufacturers have assigned different names to similar or even identical ventilatory modes so an expert system should be able to detect the ventilatory mode. The aim of this study is to evaluate the accuracy of an algorithm to detect the ventilatory mode in use. METHODS: We compared the results of a two-step algorithm designed to identify seven ventilatory modes. The algorithm was built into a software platform (BetterCare® system, Better Care SL; Barcelona, Spain) that acquires ventilatory signals through the data port of mechanical ventilators. The sample analyzed compared data from consecutive adult patients who underwent >24 h of mechanical ventilation in intensive care units (ICUs) at two hospitals. We used Cohen's kappa statistics to analyze the agreement between the results obtained with the algorithm and those recorded by ICU staff. RESULTS: We analyzed 486 records from 73 patients. The algorithm correctly labeled the ventilatory mode in 433 (89 %). We found an unweighted Cohen's kappa index of 84.5 % [CI (95 %) = (80.5 %: 88.4 %)]. CONCLUSIONS: The computerized algorithm can reliably identify ventilatory mode.

Mínimo flujo de oxígeno necesario para soporte vital durante la simulación de reanimación post parada cardiorrespiratoria / Minimum oxygen flow needed for vital support during simulated post-cardiorespiratory arrest resuscitation

De acuerdo con las guías de la AHA y la ERC, la FiO2 a administrarse debería ser aquella con la que se obtuviera una SatO2 ≥ 94%. El objetivo de este estudio es determinar el mínimo flujo de oxígeno y tiempo necesarios para alcanzar una FiO2 de 0,32 y de 0,80 durante el manejo posparada cardiaca. Se emplearon diferentes reanimadores, que fueron conectados a un pulmón artificial: Mark IV, SPUR II, Revivator Res-Q, O-TWO. Los flujos de oxígeno probados fueron 2, 5, 10 y 15 lpm. Los test estadísticos aplicados fueron Bonferroni y U de Mann-Whitney. Se obtuvo una FiO2 ≥ 0,32 con cualquiera de los flujos de oxígeno y reanimadores. Tras un mínimo de 75 s ventilando con 2 o 5 lpm, solo se consiguió una FiO2 de 0,80 con Mark IV. Se hallaron diferencias clínica y estadísticamente significativas (p < 0,05): con 15 lpm se necesitaron 35 s para alcanzar una FiO2 ≥ 0,80 con Mark IV (85,6 [0,3]) y Revivator (84,3 [1,5]) comparado con los 50 s que precisó SPUR II (87,1 [6,4]); con 2 lpm, todos los resucitadores alcanzaron una FiO2 ≥ 0,32 en 30 s(Mark IV (34,8 [1,3]), Revivator (35,7 [1,5]) y SPUR II (34,4 [2,1]), excepto O-TWO, que necesitó 35 s (36,3 [4,3]). Para alcanzar una FiO2 de 0,32 se podría emplear cualquiera de los resucitadores usando 2 lpm, aunque quizá el menos recomendable sería O-TWO. Si el objetivo fuera una FiO2 de 0,80, debería bastar con 10 lpm, usando preferiblemente Mark IV o Revivator Res-Q. En conclusión, atendiendo a los resultados de nuestro estudio, ante cualquier situación potencial, sería preferible emplear Revivator Res-Q o Mark IV que O-TWO o SPUR II (AU)

According to the ERC and the AHA guidelines, FiO2 should be titrated to achieve an O2Sat ≥ 94%. The aim of this study was to determine the minimum oxygen flow and time needed to reach an FiO2 of 0.32 and 0.80 during post-cardiac arrest care. An experimental analysis was performed that consisted of a simulated post-cardiac arrest situation. Different resuscitators were tested and connected to an artificial lung: Mark IV, SPUR II, Revivator Res-Q, O-TWO. The oxygen flow levels tested were 2, 5, 10 and 15 lpm. Bonferroni and Mann-Whitney U tests were used. An FiO2 of 0.32 or more was obtained using any of the oxygen flow and resuscitators. Only the Mark IV achieved an FiO2 of 0.80 after a minimum of 75 s ventilating with 2 or 5 lpm. Clinical and statistical differences (P < .05) were found: at 15 lpm it took 35 s to reach an FiO2 of 0.80 or more for Mark IV (85.6 [0.3]) and Revivator (84.3 [1.5]) compared to 50 s for SPUR II (87.1 [6.4]); at 2 lpm, all of the devices reached an FiO2 of ≥ 0.32 at 30 s(Mark IV (34.8 [1.3]), Revivator (35.7 [1.5]) and SPUR II (34.4 [2.1]), except for O-TWO, which took 35 s (36.3 [4.3]). Patients could be ventilated with any of the resuscitators using 2 lpm to obtain an FiO2 of 0.32, although possibly O-TWO would be the last option during the first 60 s. In order to reach an FiO2 of 0.80, ventilating with 10 lpm should be sufficient, and preferably using Mark IV or Revivator Res-Q. In conclusion, on observing the results of our study, in any possible scenario, it would be advisable to use Revivator Res-Q or Mark IV rather than O-TWO or SPUR II (AU)