COVID-19: cómo transformar un ventilador de no invasiva en un ventilador de críticos / COVID-19: how to transform a noninvasive ventilation device in a critical care ventilator

La pandemia del COVID-19 ha hecho estragos, no solo en el número de víctimas fatales sino también en la infraestructura de los hospitales y unidades de cuidados intensivos. El número limitado de respiradores es una preocupación de toda la comunidad dada la demanda masiva y a muy corto plazo de estos equipos. Esta presentación tiene como fin dar soluciones sencillas para ventilar pacientes intubados de modo mandatorio utilizando equipos de ventilación no invasiva. Las soluciones propuestas permiten 2 estrategias claras frente al COVID-19: Reemplazar las máquinas de anestesia para disponer de ellas en pacientes. Usar la opción de equipos de ventilación no invasiva para pacientes con COVID-19 a modo de «puente» y a la espera de la liberación de un respirador específico en la unidad de cuidados críticos

COVID-19 pandemic caused not only many deaths around the world but also made evident technical limitations of hospital and intensive care units (ICU). The growing demand of ICU ventilators in a short lapse of time constitutes one of the main community concerns. The main goal of this communication is to give simple solutions to transform a noninvasive ventilator in an invasive one for intubated patients. The proposal can be applied in two well defined strategies for the COVID-19 pandemic: To replace anesthesia workstations, leaving those machines to be used in patients. To apply this option in COVID-19 patients by way of a therapeutic "bridge", waiting for the release of a ventilator in the ICU

Efectividad de la ventilación de los diversos dispositivos extraglóticos durante las maniobras de reanimación. Revisión sistemática / Effectiveness of different supralottic airways during resuscitation manoeuvres. A systematic review

INTRODUCCIÓN: El uso de dispositivos extraglóticos se ha difundido ampliamente en urgencias pre e intrahospitalarias debido a la facilidad de inserción y la reducción de las interrupciones en las maniobras de reanimación cardiopulmonar. Sin embargo, la mayoría de estos estudios no especifica si dichos dispositivos aseguran una ventilación adecuada durante la reanimación cardiopulmonar. Esta revisión sistemática tiene como objetivo principal determinar si existe evidencia que demuestre que los dispositivos extraglóticos permiten una ventilación efectiva durante la reanimación. MÉTODOS: Se han utilizado las bases de datos de MEDLINE y COCHRANE para buscar estudios elegibles publicados en inglés hasta el 30 de noviembre de 2018. Los estudios considerados elegibles fueron todos aquellos que han evaluado objetivamente el volumen tidal durante las maniobras de reanimación, en diversos dispositivos extraglóticos y en pacientes mayores de 18 años. RESULTADOS: Se identificaron 3.734 artículos, de los cuales 252 eran duplicados. Solo uno evaluó objetivamente la ventilación durante las maniobras de reanimación y presentó datos relevantes para esta revisión. En este ensayo de 470 pacientes, se realizó una espirometría en 51 pacientes. Solo el 4,48% de los pacientes sobrevivieron hasta el alta hospitalaria, sin embargo, no se evaluó la relación con la efectividad de la ventilación. CONCLUSIÓN: No existe evidencia científica que demuestre que los dispositivos extraglóticos proporcionan una ventilación efectiva durante las maniobras de reanimación. La evaluación mediante espirometría, impedancia torácica y ultrasonido podría ayudar a discernir la eficacia ventilatoria de los dispositivos extraglóticos durante la reanimación cardiopulmonar y aclarar si este factor está contribuyendo de manera negativa en las dificultades experimentadas para revertir el paro cardiorrespiratorio en los pacientes

INTRODUCTION: Supraglottic airways, which are easily inserted and minimize interruptions in cardiopulmonary resuscitation manoeuvres, are now widely used in pre- and in-hospital emergencies. However, most studies in these devices do not specify whether they ensure good ventilation during CPR. This systematic review aims to determine whether there is evidence that supraglotic airways enable effective ventilation during resuscitation. METHODS: The MEDLINE and COCHRANE databases were searched for studies published in English up to 30 November 2018. Eligible studies were all those that objectively evaluated tidal volume during resuscitation maneuvers in patients over 18 years of age using various supraglottic airways. RESULTS: A total of 3734 articles were identified, of which 252 were duplicates. Only 1 objectively evaluated ventilation during resuscitation maneuvers and presented data relevant to this review. The study included 470 patients, 51 of which underwent spirometry. Only 4.48% of patients survived to hospital discharge; however, the correlation with ventilation effectiveness was not assessed. CONCLUSION: There is no scientific evidence that supraglottic airways provide effective ventilation during resuscitation maneuvers. Evaluation by spirometry, chest impedance and ultrasound may help to determine the ventilatory efficacy of supraglottic airways during CPR, and clarify whether this factor contributes to the difficulties experienced in reversing cardiorespiratory arrest

Volume-targeted ventilation with a Fabian ventilator: maintenance of tidal volumes and blood CO2.

OBJECTIVE: To analyse the performance of the Fabian +NCPAP evolution ventilator during volume guarantee (VG) ventilation in neonates at maintaining the target tidal volume and what tidal and minute volumes are required to maintain normocapnia. METHODS: Clinical and ventilator data were collected and analysed from 83 infants receiving VG ventilation during interhospital transfer. Sedation was used in 26 cases. Ventilator data were downloaded with a sampling rate of 0.5 Hz. Data were analysed using the Python computer language and its data analysis packages. RESULTS: ~107 hours of ventilator data were analysed, consisting of ~194 000 data points. The median absolute difference between the actual expiratory tidal volume (VTe) of the ventilator inflations and the target tidal volume (VTset) was 0.29 mL/kg (IQR: 0.11-0.79 mL/kg). Overall, VTe was within 1 mL/kg of VTset in 80% of inflations. VTe decreased progressively below the target when the endotracheal tube leak exceeded 50%. When leak was below 50%, VTe was below VTset by >1 mL/kg in less than 12% of inflations even in babies weighing less than 1000 g. Both VTe (r=-0.34, p=0.0022) and minute volume (r=-0.22, p=0.0567) showed a weak inverse correlation with capillary partial pressure of carbon dioxide (Pco2) values. Only 50% of normocapnic blood gases were associated with tidal volumes between 4 and 6 mL/kg. CONCLUSIONS: The Fabian ventilator delivers volume-targeted ventilation with high accuracy if endotracheal tube leakage is not excessive and the maximum allowed inflating pressure does not limit inflations. There is only weak inverse correlation between tidal or minute volumes and Pco2.

Physiologic Effects of 3 Different Neonatal Volume-Targeted Ventilation Modes in Surfactant-Deficient Juvenile Rabbits.

BACKGROUND: Different brands of volume-targeted modes may vary the location of tidal volume (VT) monitoring and whether peak inspiratory pressure is adjusted based on inspiratory, expiratory, or leak-compensated VT. These variables may result in different levels of support provided to patients, especially when an endotracheal tube (ETT) leak is present. We hypothesized that there would be no differences in gas exchange, triggering, or work of breathing between volume-targeted modes of 3 different brands of equipment in a surfactant-deficient, spontaneously breathing animal model with and without an ETT leak. METHODS: Twelve rabbits (mean ± SD 1.61 ± 0.20 kg) were sedated, anesthetized, intubated, lavaged with 0.9% saline solution, and randomized in a crossover design so that each animal was supported by 3 different volume-targeted modes at identical settings with and without an ETT leak. After 30 min, arterial blood gas, VT, and esophageal and airway pressure were recorded for each condition, and pressure-rate product and percentage of successfully triggered breaths were calculated. RESULTS: Gas exchange and the pressure-rate product were not different between the ventilators in the absence of an ETT leak. When an ETT leak was introduced, volume-guarantee modes allowed a higher percentage of triggered breaths and peak inspiratory pressure, which resulted in higher minute ventilation, pH, and lower PaCO2 than the pressure-regulated volume control mode (P < .05). CONCLUSIONS: When a moderate ETT leak was present, volume-targeted modes that used proximal VT monitoring and triggering with adaptive leak compensation capabilities appeared more effective in providing ventilation support than did a ventilator that used measurements obtained from the back at the ventilator and does not have leak compensation.

Analysis of a Pediatric Home Mechanical Ventilator Population.

BACKGROUND: The population of children requiring home mechanical ventilation has evolved over the years and has grown to include a variety of diagnoses and needs that have led to changes in the care of this unique population. The purpose of this study was to provide a descriptive analysis of pediatric patients requiring home mechanical ventilation after hospitalization and how the evolution of this technology has impacted their care. METHODS: A retrospective, observational, longitudinal analysis of 164 children enrolled in a university-affiliated home mechanical ventilation program over 26 years was performed. Data included each child's primary diagnosis, date of tracheostomy placement, duration of mechanical ventilation during hospitalization that consisted of home mechanical ventilator initiation, total length of pediatric ICU stay, ventilator settings at time of discharge from pediatric ICU, and disposition (home, facility, or died). Univariate, bivariate, and regression analysis was used as appropriate. RESULTS: The most common diagnosis requiring the use of home mechanical ventilation was neuromuscular disease (53%), followed by chronic pulmonary disease (29%). The median length of stay in the pediatric ICU decreased significantly after the implementation of a ventilator ward (70 d [30-142] vs 36 d [18-67], P = .02). The distribution of subjects upon discharge was home (71%), skilled nursing facility (24%), and died (4%), with an increase in the proportion of subjects discharged on PEEP and those going to nursing facilities over time (P = 0.02). CONCLUSIONS: The evolution of home mechanical ventilation has allowed earlier transition out of the pediatric ICU and with increasing disposition to skilled nursing facilities over time. There has also been a change in ventilator management, including increased use of PEEP upon discharge, possibly driven by changes in ventilators and in-patient practice patterns.

The efficacy of medical masks and respirators against respiratory infection in healthcare workers.

OBJECTIVE: We aimed to examine the efficacy of medical masks and respirators in protecting against respiratory infections using pooled data from two homogenous randomised control clinical trials (RCTs). METHODS: The data collected on 3591 subjects in two similar RCTs conducted in Beijing, China, which examined the same infection outcomes, were pooled. Four interventions were compared: (i) continuous N95 respirator use, (ii) targeted N95 respirator use, (iii) medical mask use and (iv) control arm. The outcomes were laboratory-confirmed viral respiratory infection, influenza A or B, laboratory-confirmed bacterial colonisation and pathogens grouped by mode of transmission. RESULTS: Rates of all outcomes were consistently lower in the continuous N95 and/or targeted N95 arms. In adjusted analysis, rates of laboratory-confirmed bacterial colonisation (RR 0.33, 95% CI 0.21-0.51), laboratory-confirmed viral infections (RR 0.46, 95% CI 0.23-0.91) and droplet-transmitted infections (RR 0.26, 95% CI 0.16-0.42) were significantly lower in the continuous N95 arm. Laboratory-confirmed influenza was also lowest in the continuous N95 arm (RR 0.34, 95% CI 0.10-1.11), but the difference was not statistically significant. Rates of laboratory-confirmed bacterial colonisation (RR 0.54, 95% CI 0.33-0.87) and droplet-transmitted infections (RR 0.43, 95% CI 0.25-0.72) were also lower in the targeted N95 arm, but not in medical mask arm. CONCLUSION: The results suggest that the classification of infections into droplet versus airborne transmission is an oversimplification. Most guidelines recommend masks for infections spread by droplets. N95 respirators, as "airborne precautions," provide superior protection for droplet-transmitted infections. To ensure the occupational health and safety of healthcare worker, the superiority of respirators in preventing respiratory infections should be reflected in infection control guidelines.

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)

Eficacia a medio y largo plazo de la ventilación no invasiva en el síndrome de hipoventilación-obesidad (estudio Pickwick) / Mid- and Long-Term Efficacy of Non-Invasive Ventilation in Obesity Hypoventilation Syndrome: The Pickwick's Study

El proyecto Pickwick es un estudio prospectivo, aleatorizado, abierto y controlado con grupos en paralelo que intenta dar respuesta a los interrogantes del síndrome de hipoventilación-obesidad (SHO), una enfermedad creciente en los países desarrollados. Para ello, pacientes con SHO fueron divididos en pacientes con índice de apneas-hipoapneas (IAH) ≥30 y <30 mediante polisomnografía. El grupo con IAH≥30 se aleatorizó a tratamiento mediante estilo de vida saludable, ventilación no invasiva (VNI) o presión en la vía aérea positiva continua (CPAP). El grupo con IAH<30, a VNI o estilo de vida saludable. Su objetivo ha sido evaluar la eficacia del tratamiento con ventilación VNI, CPAP y estilo de vida saludable (control) a medio y largo plazo en el SHO, analizando como variable primaria la PaCO2 y los días de hospitalización, respectivamente, y como variables operativas el porcentaje de abandonos por razones médicas y mortalidad. Los objetivos secundarios a medio plazo fueron: 1) evaluar la eficacia clínica-funcional, en calidad de vida, en variables polisomnográficas y ecocardiográficas; 2) investigar la importancia de los episodios apneicos y de la leptina en la génesis de la hipoventilación alveolar diurna y el cambio con los diferentes tratamientos; 3) investigar si las alteraciones metabólicas, bioquímicas y disfunción endotelial vascular dependen de la presencia de apneas e hipoapneas, y 4) cambio de marcadores inflamatorios y de daño endotelial con los tratamientos. Los objetivos secundarios a largo plazo fueron: 1) evaluar la eficacia clínico-funcional y en calidad de vida con VNI y CPAP; 2) cambio de la leptina, marcadores inflamatorios y de daño endotelial con los tratamientos; 3) cambio de la hipertensión pulmonar y otras variables ecocardiográficas, así como en la hipertensión arterial e incidencia de episodios cardiovasculares, y 4) frecuencia de abandonos y mortalidad

The Pickwick project was a prospective, randomized and controlled study, which addressed the issue of obesity hypoventilation syndrome (OHS), a growing problem in developed countries. OHS patients were divided according to apnea-hypopnea index (AHI) ≥ 30 and < 30 determined by polysomnography. The group with AHI ≥ 30 was randomized to intervention with lifestyle changes, noninvasive ventilation (NIV) or continuous positive airway pressure (CPAP); the group with AHI < 30 received NIV or lifestyle changes. The aim of the study was to evaluate the efficacy of NIV treatment, CPAP and lifestyle changes (control) in the medium and long-term management of patients with OHS. The primary variables were PaCO2 and days of hospitalization, and operating variables were the percentage of dropouts for medical reasons and mortality. Secondary medium-term objectives were: (I) to evaluate clinical-functional effectiveness on quality of life, echocardiographic and polysomnographic variables; (II) to investigate the importance of apneic events and leptin in the pathogenesis of daytime alveolar hypoventilation and change according to the different treatments; (III) to investigate whether metabolic, biochemical and vascular endothelial dysfunction disorders depend on the presence of apneas and hypopneasm and (IV) changes in inflammatory markers and endothelial damage according to treatment. Secondary long-term objectives were to evaluate: (I) clinical and functional effectiveness and quality of life with NIV and CPAP; (II) changes in leptin, inflammatory markers and endothelial damage according to treatment; (III) changes in pulmonary hypertension and other echocardiographic variables, as well as blood pressure and incidence of cardiovascular events, and (IV) dropout rate and mortality

Are All Oscillators Created Equal? In vitro Performance Characteristics of Eight High-Frequency Oscillatory Ventilators.

BACKGROUND: The mode of waveform generation and circuit characteristics differ between high-frequency oscillators. It is unknown if this influences performance. OBJECTIVES: To describe the relationships between set and delivered pressure amplitude (x0394;P), and the interaction with frequency and endotracheal tube (ETT) diameter, in eight high-frequency oscillators. METHODS: Oscillators were evaluated using a 70-ml test lung at 1.0 and 2.0 ml/cm H2O compliance, with mean airway pressures (PAW) of 10 and 20 cm H2O, frequencies of 5, 10 and 15 Hz, and an ETT diameter of 2.5 and 3.5 mm. At each permutation of PAW, frequency and ETT, the set x0394;P was sequentially increased from 15 to 50 cm H2O, or from 20 to 100% maximum amplitude (10% increments) depending on the oscillator design. The x0394;P at the ventilator (x0394;PVENT), airway opening (x0394;PAO) and within the test lung (x0394;PTRACH), and tidal volume (V(T)) at the airway opening were determined at each set x0394;P. RESULTS: In two oscillators the relationships between set and delivered x0394;P were non-linear, with a plateau in x0394;P thresholds noted at all frequencies (Dräger Babylog 8000) or ≥10 Hz (Dräger VN500). In all other devices there was a linear relationship between x0394;PVENT, x0394;PAO and x0394;PTRACH (all r2 >0.93), with differing attenuation of the pressure wave. Delivered V(T) at the different settings tested varied between devices, with some unable to deliver V(T) >3 ml at 15 Hz, and others generating V(T)>20 ml at 5 Hz and a 1:1 inspiratory-to-expiratory time ratio. CONCLUSIONS: Clinicians should be aware that modern high-frequency oscillators exhibit important differences in the delivered x0394;P and V(T).

A taxonomy for mechanical ventilation: 10 fundamental maxims.

The American Association for Respiratory Care has declared a benchmark for competency in mechanical ventilation that includes the ability to "apply to practice all ventilation modes currently available on all invasive and noninvasive mechanical ventilators." This level of competency presupposes the ability to identify, classify, compare, and contrast all modes of ventilation. Unfortunately, current educational paradigms do not supply the tools to achieve such goals. To fill this gap, we expand and refine a previously described taxonomy for classifying modes of ventilation and explain how it can be understood in terms of 10 fundamental constructs of ventilator technology: (1) defining a breath, (2) defining an assisted breath, (3) specifying the means of assisting breaths based on control variables specified by the equation of motion, (4) classifying breaths in terms of how inspiration is started and stopped, (5) identifying ventilator-initiated versus patient-initiated start and stop events, (6) defining spontaneous and mandatory breaths, (7) defining breath sequences (8), combining control variables and breath sequences into ventilatory patterns, (9) describing targeting schemes, and (10) constructing a formal taxonomy for modes of ventilation composed of control variable, breath sequence, and targeting schemes. Having established the theoretical basis of the taxonomy, we demonstrate a step-by-step procedure to classify any mode on any mechanical ventilator.

Understanding mechanical ventilators.

The respiratory care academic community has not yet adopted a standardized system for classifying and describing modes of ventilation. As a result, there is enough confusion that patient care, clinician education and even ventilator sales are all put at risk. This article summarizes a ventilator mode taxonomy that has been extensively published over the last 15 years. Specifically, the classification system has three components: a description of the control variables within breath; a description of the sequence of mandatory and spontaneous breaths; and a specification for the targeting scheme. This three-level specification provides scalability of detail to make the mode description appropriate for the particular need. At the bedside, we need only refer to a mode briefly using the first or perhaps first and second components. To distinguish between similar modes and brand names, we would need to include all components. This taxonomy uses the equation of motion for the respiratory system as the underlying theoretical framework. All terms relevant to describing modes of mechanical ventilation are defined in an extensive appendix.

Trigger performance of mid-level ICU mechanical ventilators during assisted ventilation: a bench study.

OBJECTIVE: To compare the triggering performance of mid-level ICU mechanical ventilators with a standard ICU mechanical ventilator. DESIGN: Experimental bench study. SETTING: The respiratory care laboratory of a university-affiliated teaching hospital. SUBJECT: A computerized mechanical lung model, the IngMar ASL5000. INTERVENTIONS: Ten mid-level ICU ventilators were compared to an ICU ventilator at two levels of lung model effort, three combinations of respiratory mechanics (normal, COPD and ARDS) and two modes of ventilation, volume and pressure assist/control. A total of 12 conditions were compared. MEASUREMENTS AND MAIN RESULTS: Performance varied widely among ventilators. Mean inspiratory trigger time was <100 ms for only half of the tested ventilators. The mean inspiratory delay time (time from initiation of the breath to return of airway pressure to baseline) was longer than that for the ICU ventilator for all tested ventilators except one. The pressure drop during triggering (Ptrig) was comparable with that of the ICU ventilator for only two ventilators. Expiratory Settling Time (time for pressure to return to baseline) had the greatest variability among ventilators. CONCLUSIONS: Triggering differences among these mid-level ICU ventilators and with the ICU ventilator were identified. Some of these ventilators had a much poorer triggering response with high inspiratory effort than the ICU ventilator. These ventilators do not perform as well as ICU ventilators in patients with high ventilatory demand.

A review of high frequency oscillation ventilation in the neonate.

In this study the use of high frequency oscillation (HFO) to treat neonates with respiratory failure is analysed. The theories behind gas exchange during HFO are reviewed and its specific application to neonatal care discussed. The mechanical performance of three HFO ventilators currently in use is compared with the views of medical staff operating them on a regular basis. The complex interactions between initial ventilator settings have led to difficulties in accurately comparing performance characteristics and ventilation strategies; each ventilator is seen to have its own strengths and weaknesses that contribute to the ventilator selection made. These interactions together with the specific HFO modes available on each ventilator should be taken into account when using a HFO for the first time or when switching from an alternative ventilation method. Medical staff who care for neonates suggest staff education and training into the variations of HFO will greatly improve its use in neonatal medicine.

Classification of ventilator modes: update and proposal for implementation.

Ventilator manufacturers and the respiratory care academic community have not yet adopted a standardized system for classifying and describing ventilation modes. As a result, there is enough confusion that potential sales, education, and patient care are all put at risk. This proposal summarizes a ventilator-mode classification scheme and complete lexicon that has been extensively published over the last 15 years. Specifically, the classification system has 3 components: (1) a description of the breathing pattern and control variables within breaths, (2) a description of control type used within and between breaths, (3) a detailed description of adjunctive operational algorithms. This 3-level specification provides scalability of detail to make the mode description appropriate for the particular need. At the bedside we need only refer to a mode briefly using the first component. To distinguish between similar modes and brand names we would need to use at least the first and second components. For a complete and unique mode specification (as in an operator's manual) we would use all 3 components. The classification system proposed in this article uses the equation of motion for the respiratory system as the underlying theoretical framework. All terms relevant to describing ventilation modes are defined in an extensive glossary.

Noninvasive ventilation in neuromuscular disease: equipment and application.

Noninvasive support of ventilation is commonly needed in patients with neuromuscular disease. Body ventilators, which are used rarely, function by applying intermittent negative pressure to the thorax or abdomen. More commonly, noninvasive positive-pressure ventilation (NPPV) is used. This therapy can be applied with a variety of interfaces, ventilators, and ventilator settings. The patient interface has a major impact on comfort during NPPV. The most commonly used interfaces are nasal masks and oronasal masks. Other interfaces include nasal pillows, total face masks, helmets, and mouthpieces. Theoretically, any ventilator can be attached to a mask rather than an artificial airway. Portable pressure ventilators (bi-level positive airway pressure) are available specifically to provide NPPV and are commonly used to provide this therapy. Selection of NPPV settings in patients with neuromuscular disease is often done empirically and is symptom-based. Selection of settings can also be based on the results of physiologic studies or sleep studies. The use of NPPV in this patient population is likely to expand, particularly with increasing evidence that it is life-prolonging in patients with diseases such as amyotrophic lateral sclerosis. Appropriate selection of equipment and settings for NPPV is paramount to the success of this therapy.