Spontaneous-Breathing Trials with Pressure-Support Ventilation or a T-Piece.

BACKGROUND: Spontaneous-breathing trials can be performed with the use of either pressure-support ventilation (PSV) or a T-piece. Whether PSV trials may result in a shorter time to tracheal extubation than T-piece trials, without resulting in a higher risk of reintubation, among patients who have a high risk of extubation failure is unknown. METHODS: In this multicenter, open-label trial, we randomly assigned patients who had a high risk of extubation failure (i.e., were >65 years of age or had an underlying chronic cardiac or respiratory disease) to undergo spontaneous-breathing trials performed with the use of either PSV (with a pressure-support level of 8 cm of water and no positive end-expiratory pressure) or a T-piece. The primary outcome was the total time without exposure to invasive ventilation (reported as the number of ventilator-free days) at day 28 after the initial spontaneous-breathing trial. Secondary outcomes included extubation within 24 hours and extubation within 7 days after the initial spontaneous-breathing trial, as well as reintubation within 7 days after extubation. RESULTS: A total of 969 patients (484 in the PSV group and 485 in the T-piece group) were included in the analysis. At day 28, the median number of ventilator-free days was 27 (interquartile range, 24 to 27) in the PSV group and 27 (interquartile range, 23 to 27) in the T-piece group (difference, 0 days; 95% confidence interval [CI], -0.5 to 1; P = 0.31). Extubation was performed within 24 hours in 376 patients (77.7%) in the PSV group and in 350 patients (72.2%) in the T-piece group (difference, 5.5 percentage points; 95% CI, 0.01 to 10.9), and extubation was performed within 7 days in 473 patients (97.7%) and 458 patients (94.4%), respectively (difference, 3.3 percentage points; 95% CI, 0.8 to 5.9). Reintubation was performed in 72 of 481 patients (14.9%) in the PSV group and in 65 of 477 patients (13.6%) in the T-piece group (difference, 1.3 percentage points; 95% CI, -3.1 to 5.8). Cardiac or respiratory arrest was a reason for reintubation in 9 patients (3 in the PSV group and 6 in the T-piece group). CONCLUSIONS: Among patients who had a high risk of extubation failure, spontaneous-breathing trials performed with PSV did not result in significantly more ventilator-free days at day 28 than spontaneous-breathing trials performed with a T-piece. (Supported by the French Ministry of Health; TIP-EX ClinicalTrials.gov number, NCT04227639.).

Comparação de desfechos clínicos e correlação entre funcionalidade e tempo de ventilação mecânica de pacientes em uti / Comparison of clinical outcomes and correlation between functionality and time of mechanical ventilation in icu patients / Comparación de los resultados clínicos y correlación entre la funcionalidad y el tiempo de ventilación mecánica de los pacientes en uti

O objetivo deste estudo foi comparar os desfechos clínicos dos pacientes em suporte ventilatório invasivo por período curto e prolongado e correlacionar funcionalidade e tempo de ventilação mecânica (VM). Estudo documental retrospectivo, realizado na UTI neurocirúrgica de um hospital escola. Dos prontuários clínicos foram coletados: idade, sexo, hipótese diagnóstica de internação, tempo de internação e de VM em dias, o desfecho sucesso ou falha da extubação e o nível de funcionalidade. Os prontuários foram divididos em grupo um (GI): pacientes em VM por até três dias e grupo dois (GII): pacientes em VM por mais de três dias. Foram analisados 210 prontuários, 73% dos pacientes permaneceram menos de três dias em VM. A idade média de GI foi 51,8±15,5 anos e GII 48,7±16,3 anos (p=0,20), prevalência do sexo masculino em GI (59%) e GII (68%). O acidente vascular cerebral foi o diagnóstico mais prevalente no GI (18%) e o tumor cerebral no GII (21%) e hipertensão arterial, a comorbidade mais prevalente em GI (28%) e GII (25%). O GII permaneceu maior tempo (p<0,0001) em VM e internação na UTI que o GI e percentual de sucesso no desmame/extubação menor (p=0,01) que o GI. Não houve correlação significativa entre funcionalidade e tempo de VM em GI e GII (p>0,05). Os pacientes em suporte ventilatório invasivo por período prolongado evoluíram com maior permanência em VM, maior tempo de internação na UTI e menor taxa de sucesso no desmame/extubação. O tempo de permanência em suporte ventilatório invasivo não interferiu na funcionalidade desses pacientes.

The aim of this study was to compare the clinical outcomes of patients on short- and long-term invasive ventilatory support and to correlate functionality and duration of mechanical ventilation (MV). Retrospective documental study, carried out in the neurosurgical ICU of a teaching hospital. The following were collected from the clinical records: age, gender, diagnostic hypothesis of hospitalization, length of hospital stay and MV in days, the outcome of success or failure of extubation and the level of functionality. The medical records were divided into group one (GI): patients on MV for up to three days and group two (GII): patients on MV for more than three days. A total of 210 medical records were analyzed, 73% of the patients remained on MV for less than three days. The mean age of GI was 51.8±15.5 years and GII 48.7±16.3 years (p=0.20), male prevalence in GI (59%) and GII (68%). Stroke was the most prevalent diagnosis in GI (18%) and brain tumor in GII (21%) and hypertension was the most prevalent comorbidity in GI (28%) and GII (25%). GII remained longer (p<0.0001) in MV and ICU admission than GI and the percentage of success in weaning/extubation was lower (p=0.01) than GI. There was no significant correlation between functionality and time on MV in GI and GII (p>0.05). Patients on invasive ventilatory support for a long period evolved with longer MV stays, longer ICU stays and lower weaning/extubation success rates. The length of stay on invasive ventilatory support did not interfere with the functionality of these patients.

El objetivo de este estudio fue comparar los resultados clínicos de los pacientes con soporte ventilatorio invasivo a corto y largo plazo y correlacionar la funcionalidad y el tiempo de ventilación mecánica (VM). Se trata de un estudio documental retrospectivo, realizado en la UCI neuroquirúrgica de un hospital universitario. Se recogieron los siguientes datos de las historias clínicas: edad, sexo, hipótesis diagnóstica, duración de la estancia y tiempo de VM en días, el resultado éxito o fracaso de la extubación y el nivel de funcionalidad. Las historias clínicas se dividieron en el grupo uno (GI): pacientes bajo VM hasta tres días y el grupo dos (GII): pacientes bajo VM durante más de tres días. Se analizaron 210 historias clínicas, el 73% de los pacientes permanecieron menos de tres días con VM. La edad media de GI fue de 51,8±15,5 años y la de GII de 48,7±16,3 años (p=0,20), con prevalencia masculina en GI (59%) y GII (68%). El ictus fue el diagnóstico más prevalente en GI (18%) y el tumor cerebral en GII (21%) y la hipertensión, la comorbilidad más prevalente en GI (28%) y GII (25%). El GII permaneció más tiempo (p<0,0001) en la VM y la estancia en la UCI que el GI y el porcentaje de éxito en el destete/extubación fue menor (p=0,01) que el GI. No hubo correlación significativa entre la funcionalidad y el tiempo de VM en GI y GII (p>0,05). Los pacientes con soporte ventilatorio invasivo a largo plazo evolucionaron con una mayor estancia en la VM, una mayor estancia en la UCI y una menor tasa de éxito de destete/extubación. La duración de la estancia con soporte ventilatorio invasivo no interfirió en la funcionalidad de estos pacientes.

Neurally adjusted ventilatory assist as a weaning mode for adults with invasive mechanical ventilation: a systematic review and meta-analysis.

BACKGROUND: Prolonged ventilatory support is associated with poor clinical outcomes. Partial support modes, especially pressure support ventilation, are frequently used in clinical practice but are associated with patient-ventilation asynchrony and deliver fixed levels of assist. Neurally adjusted ventilatory assist (NAVA), a mode of partial ventilatory assist that reduces patient-ventilator asynchrony, may be an alternative for weaning. However, the effects of NAVA on weaning outcomes in clinical practice are unclear. METHODS: We searched PubMed, Embase, Medline, and Cochrane Library from 2007 to December 2020. Randomized controlled trials and crossover trials that compared NAVA and other modes were identified in this study. The primary outcome was weaning success which was defined as the absence of ventilatory support for more than 48 h. Summary estimates of effect using odds ratio (OR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with accompanying 95% confidence interval (CI) were expressed. RESULTS: Seven studies (n = 693 patients) were included. Regarding the primary outcome, patients weaned with NAVA had a higher success rate compared with other partial support modes (OR = 1.93; 95% CI 1.12 to 3.32; P = 0.02). For the secondary outcomes, NAVA may reduce duration of mechanical ventilation (MD = - 2.63; 95% CI - 4.22 to - 1.03; P = 0.001) and hospital mortality (OR = 0.58; 95% CI 0.40 to 0.84; P = 0.004) and prolongs ventilator-free days (MD = 3.48; 95% CI 0.97 to 6.00; P = 0.007) when compared with other modes. CONCLUSIONS: Our study suggests that the NAVA mode may improve the rate of weaning success compared with other partial support modes for difficult to wean patients.

Ultrasound shear wave elastography for assessing diaphragm function in mechanically ventilated patients: a breath-by-breath analysis.

BACKGROUND: Diaphragm dysfunction is highly prevalent in mechanically ventilated patients. Recent work showed that changes in diaphragm shear modulus (ΔSMdi) assessed using ultrasound shear wave elastography (SWE) are strongly related to changes in Pdi (ΔPdi) in healthy subjects. The aims of this study were to investigate the relationship between ΔSMdi and ΔPdi in mechanically ventilated patients, and whether ΔSMdi is responsive to change in respiratory load when varying the ventilator settings. METHODS: A prospective, monocentric study was conducted in a 15-bed ICU. Patients were included if they met the readiness-to-wean criteria. Pdi was continuously monitored using a double-balloon feeding catheter orally introduced. The zone of apposition of the right hemidiaphragm was imaged using a linear transducer (SL10-2, Aixplorer, Supersonic Imagine, France). Ultrasound recordings were performed under various pressure support settings and during a spontaneous breathing trial (SBT). A breath-by-breath analysis was performed, allowing the direct comparison between ΔPdi and ΔSMdi. Pearson's correlation coefficients (r) were used to investigate within-individual relationships between variables, and repeated measure correlations (R) were used for determining overall relationships between variables. Linear mixed models were used to compare breathing indices across the conditions of ventilation. RESULTS: Thirty patients were included and 930 respiratory cycles were analyzed. Twenty-five were considered for the analysis. A significant correlation was found between ΔPdi and ΔSMdi (R = 0.45, 95% CIs [0.35 0.54], p < 0.001). Individual correlation displays a significant correlation in 8 patients out of 25 (r = 0.55-0.86, all p < 0.05, versus r = - 0.43-0.52, all p > 0.06). Changing the condition of ventilation similarly affected ΔPdi and ΔSMdi. Patients in which ΔPdi-ΔSMdi correlation was non-significant had a faster respiratory rate as compared to that of patient with a significant ΔPdi-ΔSMdi relationship (median (Q1-Q3), 25 (18-33) vs. 21 (15-26) breaths.min-1, respectively). CONCLUSIONS: We demonstrate that ultrasound SWE may be a promising surrogate to Pdi in mechanically ventilated patients. Respiratory rate appears to negatively impact SMdi measurement. Technological developments are needed to generalize this method in tachypneic patients. TRIAL REGISTRATION: NCT03832231 .

Uso de dexmedetomidina comparado con lidocaína y fentanilo para destete de ventilación mecánica en pacientes con COVID-19 / Use of dexmedetomidine compared with lidocaine and fentanyl for weaning from mechanical ventilation in COVID-19 patients

INTRODUCCIÓN: Uno de los mayores intereses en el campo de la salud y en torno a la pandemia de COVID-19 es el desarrollo de estrategias para reducir la transmisión de la infección por SARS-CoV-2, incluyendo la protección de los trabajadores de salud, grupo de riesgo frente a la infección por este virus (Ng et al. 2020). La extubación es un procedimiento generador de aerosoles debido a la respuesta refleja del sistema respiratorio durante esta actividad, manifestada como la presencia de tos en algunos pacientes a los que se les realiza destete del ventilador mecánico (Brewster et al. 2020). Realizar la extubación requiere la proximidad de los trabajadores de salud con los pacientes, los cuales, incluyendo los casos de pacientes con COVID-19, suelen seguir siendo infecciosos al momento de la extubación (Brewster et al. 2020, Zhou et al. 2020, Ng et al. 2020), por lo que realizar esta actividad incrementaría la probabilidad de transmisión de esta infección viral. Ante ello, diversos grupos relacionados a la anestesiología señalan como útil el empleo de medicación que reduzca la generación de tos durante la extubación, que, junto a otras medidas de protección, disminuiría la probabilidad de transmisión de la infección por SARS-CoV-2 (Brown et al. 2020, Cook et al. 2020, D'Silva et al. 2020, Tan Li et al 2020). En EsSalud, se dispone de lidocaína y fentanilo, medicamentos descritos en la literatura científica como útiles para reducir la tos en pacientes a los que se les realizará el destete de la ventilación mecánica. Sin embargo, algunos especialistas argumentan que estos agentes sedantes podrían causar depresión respiratoria, retraso en el despertar e incrementar el riesgo de delirio si son administrados por periodos largos. Adicionalmente, los especialistas argumentan que dexmedetomidina es una alternativa que ofrecería la ventaja un despertar más rápido y una menor incidencia de delirio, además de reducir la incidencia de tos durante la extubación, estos efectos facilitarían la extubación del paciente y disminuiría la transmisión del SARS-CoV-2 al equipo médico tratante en la UCI. En ese sentido, el presente documento tuvo como objetivo evaluar la eficacia y seguridad de dexmedetomidina comparado con lidocaína y fentanilo para destete de ventilación mecánica invasiva en pacientes con COVID-19. TECNOLOGÍA DE INTERÉS: Dexmedetomidina es un agonista selectivo de los receptores alfa-2 con efectos ansiolíticos, sedantes (mediados por la inhibición del locus coeruleus, el núcleo noradrenérgico predominante, situado en el tronco cerebral) y analgésicos, produciendo además un efecto simpaticolítico al disminuir la liberación de noradrenalina en las terminaciones nerviosas simpáticas. METODOLOGÍA: Se buscó la evidencia disponible al 24 de agosto del 2020 en las siguientes bases de datos bibliográficas: PubMed, The Cochrane Library y LILACS. Asimismo, se realizó una búsqueda en sitios web pertenecientes a grupos que realizan evaluaciones de tecnologías sanitarias y guías de práctica clínica, incluyendo: The Canadian Agency for Drugs and Technologies in Health (CADTH), Scottish Medicines Consortium (SMC), The National Institute for Health and Care Excellence (NICE), Institute for Quality and Efficiency in Healthcare (IQWiG), Haute Authorité de Santé (HAS), Institute for Clinical and Economic Review (ICER) y el portal BRISA (Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas). Adicionalmente, se realizó búsqueda de evidencia en sitios web de organizaciones internacionales en anestesiología o de instituciones que estén desarrollando protocolos para el manejo de pacientes con COVID-19. RESULTADOS: En la búsqueda de la evidencia no se identificaron estudios que evalúen la eficacia y seguridad de dexmedetomidina, comparado con lidocaína y fentanilo, para el destete de ventilación mecánica invasiva, en pacientes con COVID-19. Sin embargo, se identificaron: tres GPC o consensos de expertos elaborados por la Safe Airway Society, Alfred ICU y la Difficult Airway Society e instituciones colaboradoras; una RS con metaanálisis en red realizada por Tung et al., así como dos ensayos clínicos controlados, aleatorizados (ECA) que no fueron incluidos en la RS. Se debe precisar que esta RS y estos ECA no fueron realizados en la población de interés del presente reporte breve (pacientes con COVID-19); por lo que fueron incluidos como evidencia indirecta. CONCLUSIONES: En el presente documento, se evaluó la mejor evidencia científica disponible hasta la actualidad sobre eficacia y seguridad de dexmedetomidina comparado con lidocaína y fentanilo para destete de ventilación mecánica en pacientes con COVID-19. Se encontraron: tres GPC o consensos de expertos, una RS y dos ECA. La RS y los ECA incluidos aportan al reporte breve como evidencia indirecta; al no haber sido desarrollados en pacientes con COVID-19. Las guías de la Safe Airway Society (SAS), Alfred ICU y de la Difficult Airway Society (DAS) e instituciones colaboradoras que fueron elaboradas para dar recomendaciones para el proceso de extubación en pacientes con COVID-19, hacen mención a dexmedetomidina (SAS, Alfred ICU), opioides como el fentanilo (SAS y DAS) y la lidocaína (SAS, DAS) para reducir la tos durante el proceso de extubación, aunque precisan la ausencia de evidencia sobre el uso de este medicamentos en pacientes con COVID-19, señalando que se debe evaluar el balance riesgo-beneficio para el uso de los mismos. En general, las recomendaciones descritas en estos documentos proceden de consensos por opinión de expertos, y no establecen una preferencia de un medicamento sobre los otros. En cuanto a los resultados de la RS con MA en red de Tung et al., y los ECA de Kothari et al., y Hu et al., no han podido encontrar evidencia que apoye la hipótesis que el efecto de la dexmedetomidina sea superior al de lidocaína y fentanilo sobre el manejo de la tos (esto es, no se encontraron diferencias entre estos). Estos resultados deben ser interpretados con cautela debido a que la población de estudio de los mismos no son pacientes COVID-19. No obstante, la información que proporcionan puede ayudar a tener una idea del efecto que se podría esperar con el uso de cada uno de los medicamentos mencionados, tanto en eficacia como en seguridad. Al respecto, frente a una ausencia de diferencia entre dexmedetomidina en comparación con lidocaína y fentanilo, se tiene evidencia que la primera tiene un mayor riesgo de bradicardia que los dos últimos. Esto se condice con la literatura previa acerca de dicho medicamento (dexmedetomidina), donde además se describe que los adultos mayores y personas con comorbilidades presentan una mayor proporción de eventos de bradicardia atribuibles al uso de dexmedetomidina lo que, siendo que estos grupos poblacionales son los más afectados por COVID-19, sería esperable una mayor presencia de bradicardia como evento adverso en pacientes con COVID-19 que reciben dexmedetomidina, lo que llama a la precaución cuando se considera el uso de esta tecnología en estos pacientes. De este modo, la mejor evidencia disponible a la fecha (24 de agosto del 2020), procedente de tres GPC o consensos de expertos, una RS con metaanálisis en red y dos ECA, apunta a que el balance de riesgo-beneficio del empleo de dexmedetomidina comparado con el uso de lidocaína o fentanilo, en la reducción de la tos durante el destete de ventilación mecánica en pacientes con COVID-19 es de alta incertidumbre, especialmente por el hecho que la dexmedetomidina está asociada a un mayor riesgo de reacciones adversas frente a los otros dos medicamentos, especialmente en lo referente a bradicardia. Por ello, con este cuerpo de evidencia, el IETSI no ha encontrado sustento técnico que pueda apoyar una recomendación a favor del uso de dexmedetomidina por sobre el de lidocaína o fentanilo en pacientes COVID-19 para reducir la tos al momento de la extubación.

Reducing Aerosol Generation During Ventilator Weaning in a Coronavirus Disease 2019 Patient Using a Supraglottic Airway: A Case Report.

We report weaning from mechanical ventilation with no coughing in a patient with coronavirus disease 2019 (COVID-19). Substituting the endotracheal tube for a supraglottic airway (SGA), which is less stimulating to the trachea, can reduce coughing with weaning from mechanical ventilation and extubation. Personal protective equipment is in short supply worldwide. Reducing spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is beneficial in terms of occupational health of health care workers.

Ciência SP COVID-19: tecnologia para ventiladores pulmonares

Um tomógrafo por impedância elétrica desenvolvido com apoio da FAPESP pela empresa Timpel monitora pacientes que necessitam de ventilação artificial. Seu uso ajuda a aumentar a disponibilidade de ventiladores pulmonares e, consequentemente, de leitos em unidades de terapia intensiva (UTIs) para pacientes com COVID-19 em estado grave.

Comparison of T-piece and pressure support ventilation as spontaneous breathing trials in critically ill patients: a systematic review and meta-analysis.

BACKGROUND: The effect of alternative spontaneous breathing trial (SBT) techniques on extubation success and other clinically important outcomes is uncertain. A systematic review and meta-analysis was performed to clarify the preferable SBT (T-piece or pressure support ventilation [PSV]). METHODS: We searched the PubMed, Cochrane, and Embase databases for randomized controlled trials (RCTs) from inception to the 31st of July 2019. We included RCTs involving adult patients (> 18 years) who underwent at least two different SBT methods. All authors reported our primary outcome of successful extubation rate and clearly compared PS versus T-piece with clinically relevant secondary outcomes (rate of reintubation, ICU and hospital length of stay, and ICU and hospital mortality). Results were expressed as odds ratio (OR) and mean difference (MD) with accompanying 95% confidence interval (CI). RESULTS: Ten RCTs including 3165 patients were included. The results of this meta-analysis showed that there was no significant difference in the successful extubation rate between the T-piece group and PS group (odds ratio [OR] = 0.91; 95% CI, 0.78-1.07; P = 0.27; I2 = 79%). In addition, compared with the PS group, the T-piece group showed no significant difference in the rate of reintubation (odds ratio [OR] = 0.99; 95% CI, 0.78-1.26; P = 0.95; I2 = 5%), ICU mortality (odds ratio [OR] = 1.22; 95% CI, 0.83-1.80; P = 0.30; I2 = 0%), hospital mortality (odds ratio [OR] = 1.36; 95% CI, 0.99-1.87; P = 0.06; I2 = 19%), ICU length of stay (mean difference = - 0.10; 95% CI, - 0.59 to 0.39; P = 0.69; I2 = 13%), and hospital length of stay (mean difference = - 0.82;95% CI, - 2.2 to 0.55; P = 0.24; I2 = 0%). CONCLUSIONS: T-piece and PSV as SBTs are considered to have comparable predictive power of successful extubation in critically ill patients. The analysis of secondary outcomes also shows no significant difference in the rate of reintubation, ICU and hospital length of stay, and ICU and hospital mortality between the two groups. Further randomized controlled studies of SBTs are still required.

Abdominal functional electrical stimulation to assist ventilator weaning in critical illness: a double-blinded, randomised, sham-controlled pilot study.

BACKGROUND: For every day a person is dependent on mechanical ventilation, respiratory and cardiac complications increase, quality of life decreases and costs increase by > $USD 1500. Interventions that improve respiratory muscle function during mechanical ventilation can reduce ventilation duration. The aim of this pilot study was to assess the feasibility of employing an abdominal functional electrical stimulation (abdominal FES) training program with critically ill mechanically ventilated patients. We also investigated the effect of abdominal FES on respiratory muscle atrophy, mechanical ventilation duration and intensive care unit (ICU) length of stay. METHODS: Twenty critically ill mechanically ventilated participants were recruited over a 6-month period from one metropolitan teaching hospital. They were randomly assigned to receive active or sham (control) abdominal FES for 30 min, twice per day, 5 days per week, until ICU discharge. Feasibility was assessed through participant compliance to stimulation sessions. Abdominal and diaphragm muscle thickness were measured using ultrasound 3 times in the first week, and weekly thereafter by a blinded assessor. Respiratory function was recorded when the participant could first breathe independently and at ICU discharge, with ventilation duration and ICU length of stay also recorded at ICU discharge by a blinded assessor. RESULTS: Fourteen of 20 participants survived to ICU discharge (8, intervention; 6, control). One control was transferred before extubation, while one withdrew consent and one was withdrawn for staff safety after extubation. Median compliance to stimulation sessions was 92.1% (IQR 5.77%) in the intervention group, and 97.2% (IQR 7.40%) in the control group (p = 0.384). While this pilot study is not adequately powered to make an accurate statistical conclusion, there appeared to be no between-group thickness changes of the rectus abdominis (p = 0.099 at day 3), diaphragm (p = 0.652 at day 3) or combined lateral abdominal muscles (p = 0.074 at day 3). However, ICU length of stay (p = 0.011) and ventilation duration (p = 0.039) appeared to be shorter in the intervention compared to the control group. CONCLUSIONS: Our compliance rates demonstrate the feasibility of using abdominal FES with critically ill mechanically ventilated patients. While abdominal FES did not lead to differences in abdominal muscle or diaphragm thickness, it may be an effective method to reduce ventilation duration and ICU length of stay in this patient group. A fully powered study into this effect is warranted. TRIAL REGISTRATION: The Australian New Zealand Clinical Trials Registry, ACTRN12617001180303. Registered 9 August 2017.

Neurally adjusted ventilatory assist (NAVA) versus pressure support ventilation: patient-ventilator interaction during invasive ventilation delivered by tracheostomy.

BACKGROUND: Prolonged weaning is a major issue in intensive care patients and tracheostomy is one of the last resort options. Optimized patient-ventilator interaction is essential to weaning. The purpose of this study was to compare patient-ventilator synchrony between pressure support ventilation (PSV) and neurally adjusted ventilatory assist (NAVA) in a selected population of tracheostomised patients. METHODS: We performed a prospective, sequential, non-randomized and single-centre study. Two recording periods of 60 min of airway pressure, flow, and electrical activity of the diaphragm during PSV and NAVA were recorded in a random assignment and eight periods of 1 min were analysed for each mode. We searched for macro-asynchronies (ineffective, double, and auto-triggering) and micro-asynchronies (inspiratory trigger delay, premature, and late cycling). The number and type of asynchrony events per minute and asynchrony index (AI) were determined. The two respiratory phases were compared using the non-parametric Wilcoxon test after testing the equality of the two variances (F-Test). RESULTS: Among the 61 patients analysed, the total AI was lower in NAVA than in PSV mode: 2.1% vs 14% (p < 0.0001). This was mainly due to a decrease in the micro-asynchronies index: 0.35% vs 9.8% (p < 0.0001). The occurrence of macro-asynchronies was similar in both ventilator modes except for double triggering, which increased in NAVA. The tidal volume (ml/kg) was lower in NAVA than in PSV (5.8 vs 6.2, p < 0.001), and the respiratory rate was higher in NAVA than in PSV (28 vs 26, p < 0.05). CONCLUSION: NAVA appears to be a promising ventilator mode in tracheotomised patients, especially for those requiring prolonged weaning due to the decrease in asynchronies.

Role of physical therapists in the weaning and extubation procedures of pediatric and neonatal intensive care units: a survey.

BACKGROUND: Weaning a patient from mechanical ventilation is a complex procedure that involves clinical and contextual aspects. Mechanical ventilation also depends on the characteristics of health professionals who work in intensive care. OBJECTIVE: This study described the organizational aspects associated with the physical therapist's performance in the weaning procedure from mechanical ventilation and extubation in neonatal, pediatric and mixed (neonatal and pediatric) intensive care units in Brazil. METHODS: In order to identify the existing intensive care units in Brazil, data from the National Health Facilities Census was used to enable the researchers to obtain information about registered units. A cross-sectional survey was carried out by sending an electronic questionnaire to 298 neonatal, pediatric and mixed intensive care units in Brazil. RESULTS: This study assessed questionnaires from 146 intensive care units (49.3% neonatal, 35.6% pediatric and 15.1% mixed). A total of 57.5% of these units applied mechanical ventilation weaning protocols, and a physical therapist frequently conducted this procedure (66.7%). However, the clinician responsible for conducting the weaning and deciding when to do extubation varied regardless of ICU patient age profile. Regardless of the type of hospital or the type of units, most of these had a dedicated physical therapist. However, physical therapy care 24h/7 days per week was predominantly in pediatric intensive care units (56.0%), and in public hospitals (45.9%). Moreover, when the physical therapist was available 24h/7 days per week, (s)he was responsible for the mechanical ventilation extubation decision and patients were successfully extubated on the first attempt. CONCLUSION: In this survey, intensive care units using physical therapy assistance 24h/7 days per week were associated with the use of a mechanical ventilation weaning protocol, an extubation decision and success commonly on the first attempt of extubation.

Mechanical Ventilation and Extracorporeal Membrane Oxygena tion in Acute Respiratory Insufficiency

Mechanical ventilation is life-saving for patients with acute respiratory insufficiency. In a German prevalence study, 13.6% of patients in intensive care units received mechanical ventilation for more than 12 hours; 20% of these patients received mechanical ventilation as treatment for acute respiratory distress syndrome (ARDS). The new S3 guideline is the first to contain recommendations for the entire process of treatment in these groups of patients (indications, ventilation modes/parameters, accompanying measures, treatments for refractory impairment of gas exchange, weaning, and follow-up care). This guideline was developed according to the GRADE methods. Pertinent publications were identified by a systematic search of the literature, the quality of the evidence was evaluated, a risk/benefit assessment was conducted, and recommendations were issued by interdisciplinary consensus. Mechanical ventilation is recommended as primary treatment for patients with severe ARDS. In other patient groups, non-invasive ventilation can lower mortality. If mechanical ventilation is needed, ventilation modes allowing spontaneous breathing seem beneficial (quality of evidence [QoE]: very low). Protective ventilation (high positive end-expiratory pressure, low tidal volume, limited peak pressure) improve the survival of ARDS patients (QoE: high). If a severe impairment of gas exchange is present, prone positioning lessens mortality (QoE: high). Veno-venous extracorporeal membrane oxygenation (vvECMO) has not unequivocally been shown to improve survival. Early mobilization and weaning protocols can shorten the duration of ventilation (QoE: moderate). Recommendations for patients undergoing mechanical ventilation include lung-protective ventilation, early spontaneous breathing and mobilization, weaning protocols, and, for those with severe impairment of gas exchange, prone positioning. It is further recommended that patients with ARDS and refractory impairment of gas exchange should be transferred to an ARDS/ECMO center, where extracorporeal methods should be applied only after application of all other therapeutic options.

Patient-ventilator interaction with conventional and automated management of pressure support during difficult weaning from mechanical ventilation.

PURPOSE: Optimizing pressure support ventilation (PSV) can improve patient-ventilator interaction. We conducted a two-center, randomized cross-over study to determine whether automated PSV lowers asynchrony rate during difficult weaning from mechanical ventilation. METHODS: Thirty patients failing the first weaning attempt were randomly ventilated for 2 three-hour consecutive periods with: 1)PSV managed by physicians (convPSV); 2)PSV managed by Smartcare® (autoPSV). These 2 periods were applied in the afternoon and overnight, for a 12-h total study time. Two independent clinicians offline analyzed ventilator waveforms to compute asynchrony index(AI). RESULTS: AI was lower during autoPSV than during convPSV (medians[interquartile ranges] 5.1[2.6-9.5]% vs. 7.3[2.3-13.4]%, p = 0.02), without changes in the proportion of patients with AI>10%(p = 0.31). Pressure support (PS) variability was higher during autoPSV (p < 0.001), but average PS did not vary. In patients with baseline PS > 12 cmH2O (n = 15), PS and tidal volume were lower with autoPSV (12 [10-15]cmH2O vs. 15 [14-18]cmH2O,p = 0.003; 7.2[6.2-8.3]ml/Kg vs. 8.2[7.1-9.1]ml/Kg, p = 0.02) and AI reduction was driven by lower tidal volume (p = 0.03). In patients with baseline PS ≤ 12 cmH2O, AI reduction during autoPSV was mediated by increased PS variability (p = 0.04). CONCLUSION: During difficult weaning, autoPSV improves patient-ventilator interaction by lowering tidal volume and enhancing PS variability. In expert centres, however, the size effect of the intervention appears clinically small, likely because physicians themselves adequately limit PS and tidal volume.

Predicting Extubation Outcome by Cough Peak Flow Measured Using a Built-in Ventilator Flow Meter.

BACKGROUND: Successful weaning from mechanical ventilation depends on the patient's ability to cough efficiently. Cough peak flow (CPF) could predict extubation success using a dedicated flow meter but required patient disconnection. We aimed to predict extubation outcome using an overall model, including cough performance assessed by a ventilator flow meter. METHODS: This was a prospective observational study conducted from November 2014 to October 2015. Before and after a spontaneous breathing trial, subjects were encouraged to cough as strongly as possible before freezing the ventilator screen to assess CPF and tidal volume (VT) in the preceding inspiration. Early extubation success rate was defined as the proportion of subjects not re-intubated 48 h after extubation. Diagnostic performance of CPF and VT was assessed by using the area under the curve of the receiver operating characteristic curve. Cut-off values for CPF and VT were defined according to median values and used to describe the performance of a predictive test combining them with risk factors of early extubation failure. RESULTS: Among 673 subjects admitted, 92 had a cough assessment before extubation. For the 81 subjects with early extubation success, the median CPF was -67.7 L/min, and median VT was 0.646 L. For the 11 subjects with early extubation failure, the median CPF was -57.3 L/min, and median VT was 0.448 L. Area under the curve was 0.61 (95% CI 0.37-0.83) for CPF and 0.64 (95% CI 0.42-0.84) for CPF/VT combined. After dichotomization (CPF < -60 L/min or VT > 0.55 L), there was a synergistic effect to predict early extubation success (P < .001). The predictive value of success reached 94.2% for CPF/VT combined. The overall model including pH before extubation < 7.45 reached a 66.7% predictive value of failure. CONCLUSIONS: CPF measured using the flow meter of an ICU ventilator was able to predict extubation success and to build a composite score to predict extubation failure. The results were close to that found in previous studies that used a dedicated flow meter. This could help to identify high-risk subjects to prevent extubation failure. (ClinicalTrials.gov registration NCT02847221.).

Spontaneous Breathing Trials With T-Piece or Pressure Support Ventilation.

Spontaneous breathing trials (SBTs) are among the most commonly employed techniques to facilitate weaning from mechanical ventilation. The preferred SBT technique, however, is still unclear. To clarify the preferable SBT (T-piece or pressure support ventilation [PSV]), we conducted this systematic review. We then searched the MEDLINE, EMBASE, SciELO, Google Scholar, CINAHL, ClinicalTrials.gov, and Cochrane CENTRAL databases through June 2015, without language restrictions. We included randomized controlled trials involving adult subjects being weaned from mechanical ventilation comparing T-piece with PSV and reporting (1) weaning failure, (2) re-intubation rate, (3) ICU mortality, or (4) weaning duration. Anticipating clinical heterogeneity among the included studies, we compared prespecified subgroups: (1) simple, difficult, or prolonged weaning and (2) subjects with COPD. We summarized the quality of evidence for intervention effects using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology. We identified 3,674 potentially relevant studies and reviewed 23 papers in full. Twelve studies (2,161 subjects) met our inclusion criteria. Overall, the evidence was of very low to low quality. SBT technique did not influence weaning success (risk ratio 1.23 [0.94-1.61]), ICU mortality (risk ratio 1.11 [0.80-1.54]), or re-intubation rate (risk ratio 1.21 [0.90-1.63]). Prespecified subgroup analysis suggested that PSV might be superior to T-piece with regard to weaning success for simple-to-wean subjects (risk ratio 1.44 [1.11-1.86]). For the prolonged-weaning subgroup, however, T-piece was associated with a shorter weaning duration (weighted mean difference -3.08 [-5.24 to -0.92] d). In conclusion, low-quality evidence is available concerning this topic. PSV may be associated with lower weaning failure rates in the simple-to-wean subgroup. In contrast, in prolonged-weaning subjects, T-piece may be related to a shorter weaning duration, although this is at high risk of bias. Further study of the difficult-to-wean and COPD subgroups is required.

Critical care ultrasonography in acute respiratory failure.

Acute respiratory failure (ARF) is a leading indication for performing critical care ultrasonography (CCUS) which, in these patients, combines critical care echocardiography (CCE) and chest ultrasonography. CCE is ideally suited to guide the diagnostic work-up in patients presenting with ARF since it allows the assessment of left ventricular filling pressure and pulmonary artery pressure, and the identification of a potential underlying cardiopathy. In addition, CCE precisely depicts the consequences of pulmonary vascular lesions on right ventricular function and helps in adjusting the ventilator settings in patients sustaining moderate-to-severe acute respiratory distress syndrome. Similarly, CCE helps in identifying patients at high risk of ventilator weaning failure, depicts the mechanisms of weaning pulmonary edema in those patients who fail a spontaneous breathing trial, and guides tailored therapeutic strategy. In all these clinical settings, CCE provides unparalleled information on both the efficacy and tolerance of therapeutic changes. Chest ultrasonography provides further insights into pleural and lung abnormalities associated with ARF, irrespective of its origin. It also allows the assessment of the effects of treatment on lung aeration or pleural effusions. The major limitation of lung ultrasonography is that it is currently based on a qualitative approach in the absence of standardized quantification parameters. CCE combined with chest ultrasonography rapidly provides highly relevant information in patients sustaining ARF. A pragmatic strategy based on the serial use of CCUS for the management of patients presenting with ARF of various origins is detailed in the present manuscript.

Smart Care™ versus respiratory physiotherapy-driven manual weaning for critically ill adult patients: a randomized controlled trial.

INTRODUCTION: A recent meta-analysis showed that weaning with SmartCare™ (Dräger, Lübeck, Germany) significantly decreased weaning time in critically ill patients. However, its utility compared with respiratory physiotherapist-protocolized weaning is still a matter of debate. We hypothesized that weaning with SmartCare™ would be as effective as respiratory physiotherapy-driven weaning in critically ill patients. METHODS: Adult critically ill patients mechanically ventilated for more than 24 hours in the adult intensive care unit of the Albert Einstein Hospital, São Paulo, Brazil, were randomly assigned to be weaned either by progressive discontinuation of pressure support ventilation (PSV) with SmartCare™. Demographic data, respiratory function parameters, level of PSV, tidal volume (VT), positive end-expiratory pressure (PEEP), inspired oxygen fraction (FIO2), peripheral oxygen saturation (SpO2), end-tidal carbon dioxide concentration (EtCO2) and airway occlusion pressure at 0.1 second (P0.1) were recorded at the beginning of the weaning process and before extubation. Mechanical ventilation time, weaning duration and rate of extubation failure were compared. RESULTS: Seventy patients were enrolled 35 in each group. There was no difference between the two groups concerning age, sex or diagnosis at study entry. There was no difference in maximal inspiratory pressure, maximal expiratory pressure, forced vital capacity or rapid shallow breathing index at the beginning of the weaning trial. PEEP, VT, FIO2, SpO2, respiratory rate, EtCO2 and P0.1 were similar between the two groups, but PSV was not (median: 8 vs. 10 cmH2O; p =0.007). When the patients were ready for extubation, PSV (8 vs. 5 cmH2O; p =0.015) and PEEP (8 vs. 5 cmH2O; p <0.001) were significantly higher in the respiratory physiotherapy-driven weaning group. Total duration of mechanical ventilation (3.5 [2.0-7.3] days vs. 4.1 [2.7-7.1] days; p =0.467) and extubation failure (2 vs. 2; p =1.00) were similar between the two groups. Weaning duration was shorter in the respiratory physiotherapy-driven weaning group (60 [50-80] minutes vs. 110 [80-130] minutes; p <0.001). CONCLUSION: A respiratory physiotherapy-driven weaning protocol can decrease weaning time compared with an automatic system, as it takes into account individual weaning difficulties. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT02122016 . Date of Registration: 27 August 2013.

[High-Flow Nasal Cannulae (HFNC) in Neonates: A Survey of Current Practice in Level 1 Perinatal Centres in the German State of North Rhine-Westphalia]. / High-flow nasal cannulae (HFNC) in der Neonatologie: Umfrage über Einsatz und Erfahrungen in den nordrheinwestfälischen Level 1 Perinatalzentren.

INTRODUCTION: High-flow nasal cannulae (HFNC) is a kind of non-invasive respiratory support. In recent years, its application has gained increasing popularity for treating neonates with respiratory failure. Within this study, neonatologists employed at high level perinatal centres within the region of North Rhine-Westphalia, Germany were interviewed. We evaluated their personal experience as well as the underlying indication for using HFNC. METHOD: We undertook an online survey. RESULTS: 93% of the interviewed participants use HFNC systems in their NICU. The most prominent indications were CPAP-weaning, nasal trauma, and apnoea of prematurity. Both initial flow and maximum and minimum flow rates varied widely. The primary benefit of HFNC vs. conventional CPAP was the improved neonate tolerance, less nasal traumata and ease of application and care. A common disadvantage was the inability to conduct PEEP measurements. DISCUSSION: The application of the HFNC system is increasing for specific neonatal indications, thereby increasing the data for the evaluation of effectivity and safety. Nevertheless, detailed investigations of the appropriate flow rate settings are still lacking.

Abdominal Functional Electrical Stimulation to Assist Ventilator Weaning in Acute Tetraplegia: A Cohort Study.

BACKGROUND: Severe impairment of the major respiratory muscles resulting from tetraplegia reduces respiratory function, causing many people with tetraplegia to require mechanical ventilation during the acute stage of injury. Abdominal Functional Electrical Stimulation (AFES) can improve respiratory function in non-ventilated patients with sub-acute and chronic tetraplegia. The aim of this study was to investigate the clinical feasibility of using an AFES training program to improve respiratory function and assist ventilator weaning in acute tetraplegia. METHODS: AFES was applied for between 20 and 40 minutes per day, five times per week on four alternate weeks, with 10 acute ventilator dependent tetraplegic participants. Each participant was matched retrospectively with a ventilator dependent tetraplegic control, based on injury level, age and sex. Tidal Volume (VT) and Vital Capacity (VC) were measured weekly, with weaning progress compared to the controls. RESULTS: Compliance to training sessions was 96.7%. Stimulated VT was significantly greater than unstimulated VT. VT and VC increased throughout the study, with mean VC increasing significantly (VT: 6.2 mL/kg to 7.8 mL/kg VC: 12.6 mL/kg to 18.7 mL/kg). Intervention participants weaned from mechanical ventilation on average 11 (sd: ± 23) days faster than their matched controls. CONCLUSION: The results of this study indicate that AFES is a clinically feasible technique for acute ventilator dependent tetraplegic patients and that this intervention may improve respiratory function and enable faster weaning from mechanical ventilation. TRIAL REGISTRATION: ClinicalTrials.gov NCT02200393.