Higher versus lower positive end-expiratory pressure in patients without acute respiratory distress syndrome: a meta-analysis of randomized controlled trials.

BACKGROUND: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the association of higher positive end-expiratory pressure (PEEP), as opposed to lower PEEP, with hospital mortality in adult intensive care unit (ICU) patients undergoing invasive mechanical ventilation for reasons other than acute respiratory distress syndrome (ARDS). METHODS: We performed an electronic search of MEDLINE, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, and Web of Science from inception until June 16, 2021 with no language restrictions. In addition, a research-in-progress database and grey literature were searched. RESULTS: We identified 22 RCTs (2225 patients) comparing higher PEEP (1007 patients) with lower PEEP (991 patients). No statistically significant association between higher PEEP and hospital mortality was observed (risk ratio 1.02, 95% confidence interval 0.89-1.16; I2 = 0%, p = 0.62; low certainty of evidence). Among secondary outcomes, higher PEEP was associated with better oxygenation, higher respiratory system compliance, and lower risk of hypoxemia and ARDS occurrence. Furthermore, barotrauma, hypotension, duration of ventilation, lengths of stay, and ICU mortality were similar between the two groups. CONCLUSIONS: In our meta-analysis of RCTs, higher PEEP, compared with lower PEEP, was not associated with mortality in patients without ARDS receiving invasive mechanical ventilation. Further large high-quality RCTs are required to confirm these findings.

Dynamic hyperinflation and intrinsic positive end-expiratory pressure in ARDS patients.

BACKGROUND: In ARDS patients, changes in respiratory mechanical properties and ventilatory settings can cause incomplete lung deflation at end-expiration. Both can promote dynamic hyperinflation and intrinsic positive end-expiratory pressure (PEEP). The aim of this study was to investigate, in a large population of ARDS patients, the presence of intrinsic PEEP, possible associated factors (patients' characteristics and ventilator settings), and the effects of two different external PEEP levels on the intrinsic PEEP. METHODS: We made a secondary analysis of published data. Patients were ventilated with a tidal volume of 6-8 mL/kg of predicted body weight, sedated, and paralyzed. After a recruitment maneuver, a PEEP trial was run at 5 and 15 cmH2O, and partitioned mechanics measurements were collected after 20 min of stabilization. Lung computed tomography scans were taken at 5 and 45 cmH2O. Patients were classified into two groups according to whether or not they had intrinsic PEEP at the end of an expiratory pause. RESULTS: We enrolled 217 sedated, paralyzed patients: 87 (40%) had intrinsic PEEP with a median of 1.1 [1.0-2.3] cmH2O at 5 cmH2O of PEEP. The intrinsic PEEP significantly decreased with higher PEEP (1.1 [1.0-2.3] vs 0.6 [0.0-1.0] cmH2O; p < 0.001). The applied tidal volume was significantly lower (480 [430-540] vs 520 [445-600] mL at 5 cmH2O of PEEP; 480 [430-540] vs 510 [430-590] mL at 15 cmH2O) in patients with intrinsic PEEP, while the respiratory rate was significantly higher (18 [15-20] vs 15 [13-19] bpm at 5 cmH2O of PEEP; 18 [15-20] vs 15 [13-19] bpm at 15 cmH2O). At both PEEP levels, the total airway resistance and compliance of the respiratory system were not different in patients with and without intrinsic PEEP. The total lung gas volume and lung recruitability were also not different between patients with and without intrinsic PEEP (respectively 961 [701-1535] vs 973 [659-1433] mL and 15 [0-32] % vs 22 [0-36] %). CONCLUSIONS: In sedated, paralyzed ARDS patients without a known obstructive disease, the amount of intrinsic PEEP during lung-protective ventilation is negligible and does not influence respiratory mechanical properties.

Medical Devices; Anesthesiology Devices; Classification of the Positive Airway Pressure Delivery System. Final order.

The Food and Drug Administration (FDA or we) is classifying the positive airway pressure delivery system into class II (special controls). The special controls that apply to the device type are identified in this order and will be part of the codified language for the positive airway pressure delivery system's classification. We are taking this action because we have determined that classifying the device into class II (special controls) will provide a reasonable assurance of safety and effectiveness of the device. We believe this action will also enhance patients' access to beneficial innovative devices, in part by reducing regulatory burdens.

Auto-titrating versus standard continuous positive airway pressure for the treatment of obstructive sleep apnea: results of a meta-analysis.

STUDY OBJECTIVE: To compare the effectiveness of auto-titrating continuous positive airway pressure (APAP) versus conventional continuous positive airway pressure (CPAP) in reducing the apnea-hypopnea index (AHI), reducing the mean airway pressure, improving subjective sleepiness, and improving treatment adherence in patients with obstructive sleep apnea (OSA). DESIGN: Meta-analysis and metaregression of published randomized trials comparing APAP to CPAP. SETTING: N/A. PARTICIPANTS: N/A. INTERVENTIONS: N/A. RESULTS: We identified 9 randomized trials studying a total of 282 patients. Compared to CPAP, there was no significant advantage of APAP in reducing AHI or sleepiness (pooled APAP-CPAP posttreatment AHI and Epworth Sleepiness Scale score = -0.20 events per hour, 95% confidence interval:[-0.74,0.35], and -0.56 [-1.4,0.3] respectively). The use of APAP reduced the mean applied pressure across the night by 2.2 cm water [1.9,2.5] compared to CPAP. Adherence with therapy was not substantially improved with APAP; pooled estimate of improvement was 0.20 hours per night ([-0.16,0.57], P = .28) using a random-effects model. CONCLUSIONS: Compared to standard CPAP, APAP is associated with a reduction in mean pressure. However, APAP and standard CPAP were similar in adherence and their ability to eliminate respiratory events and to improve subjective sleepiness. Given that APAP is more costly than standard CPAP, APAP should not be considered first-line chronic therapy in all patients with OSA. However, APAP may be useful in other situations (eg, home titrations, detection of mouth leak) or in certain subgroups of patients with OSA. Identifying circumstances in which APAP is a definite improvement over CPAP in terms of costs or effects should be the focus of future studies.

Volume and pressure modes of mechanical ventilation in pediatric patients.

There are few controlled pediatric studies comparing the various modes of ventilation in terms of patient outcomes. Thus at this time the choice of ventilator mode depends largely on the apparatus available, the patient's disease state, and personal preference based on one's experience. The next generation of ventilators may well allow the use of the best of both modes, setting both pressure and volume minimums and maximums, safely meeting ventilation targets. Today's challenges are to become familiar with the various modes of ventilators available, understand the developing physiology of the lung and lung disease pathophysiology, and incorporate all this into proper ventilator strategies to prevent ventilator-induced lung injury.

[Invasive ventilation. Classification, technique and clinical experiences with BiPAP/APRV (Biphasic Positive Airway Pressure/Airway Pressure Release Ventilation)]. / Invasiv ventilation. Klassifikation, teknik og kliniske erfaringer med BiPAP/APRV.

BiPAP (bilevel or biphasic positive airway pressure) and APRV (airway pressure release ventilation) are new, and from a technical viewpoint closely related techniques recently introduced to the field of invasive ventilatory support. BiPAP/APRV can be described as a pressure controlled continuous high flow positive airway pressure system with a time-cycled change between a high inspiratory pressure level and a lower expiratory pressure level. Due to highly sensitive valves placed in the inspiratory and expiratory part of the system, unrestricted spontaneous breathing is possible at any moment of the mechanically supported ventilatory cycle. During invasive ventilation BiPAP offers potential advantages by allowing unrestricted spontaneous breathing thus reducing the need for sedation and facilitating weaning. APRV has primarily been investigated in conditions of moderate to severe acute lung injury and it seems that APRV is associated with less detrimental effects on the cardiopulmonary system compared to conventional ventilatory strategies. Apart from a review of the literature the article gives a classification and a technical description of the systems and focuses on the practical approach to BiPAP/APRV, e.g. the initiation and adjustment of respiratory support and the weaning from ventilatory support when applying these techniques.

Tratamiento del síndrome de apnea obstructiva del sueño mediante CPAP nasal / Nasal CPAP as treatment of obstructive sleep syndrome

Los niños con malformaciones craneofaciales tienen un alto riesgo de presentar síndrome de apnea obstructiva del sueño(SAOS)Cuando no es posible realizar cirugías reconstructivas totales al momento del diagnóstico del SAOS debe optarse por otras medidas terapéuticas.Presentamos una niña con una severa retromicrognatia y anquilosis temporomandibular en la que se implementó un tratamiento funcional mediante la aplicación de presión positiva continua en la vía aérea(continuos positive airway pressure:CPAP)a través de una máscara nasal

BIPAP (Biphasic Positive Airway Pressure): un modo ventilatorio no convencional / Biphasic positive airway pressure: a non conventional ventilatory mode

La presente revisión, realizada con la recopilación y el análisis de la bibliografía obtenida por intermedio de MEDLINE, tiene por objeto estudiar un modo ventilatorio no convencional, destacar las ventajas terapéuticas de su aplicación en Terapia Intensiva y lograr una mayor difusión del mismo. Biphasic Positive Airway Pressure (BIPAP) es un modo ventilatorio limitado por presión ciclado por tiempo, donde dos niveles de Continuous Positive Airway Pressure (CPAP) diferentes, que alternan a intervalos de tiempo preestablecidos, determinan la ventilación mecánica. Además permite la respiración espontánea del paciente, sin límites en ambos valores de CPAP y en cualquier momento del ciclo respiratorio. La duración de cada fase (Tlow, Thigh), como los niveles de presión correspondientes (Plow, Phigh) son programados independientemente y de esta manera es posible modificar la proporción del componente mecánico y el trabajo realizado por el paciente. La combinación de respiración mecánica y espontánea mejora el intercambio gaseoso, optimiza la disponibilidad de oxígeno y favorece la adaptación del paciente al aparato, en consecuencia disminuye la necesidad de sedación y relajación. Finalmente proponemos modificar la actual denominación a "BIFPAP" y contribuir a esclarecer la confusión existente con Bilevel Positive Airway Pressure (BiPAP), un método no invasivo y ampliamente utilizado