649CHAPTER 55 Noninvasive Ventilation in the Pediatric Intensive Care Unit Cochrane review by Shah and colleagues suggested a decrease in need for intubation and shorter hospital stay with the use of[.]
CHAPTER 55 Noninvasive Ventilation in the Pediatric Intensive Care Unit 649 Cuirass shell Suprasternal notch Chest shell Flexible hose to pump unit Straps Pubic crest Straps Flexible hose A Post To pump unit Pump unit B • Fig 55.5 Cuirass ventilator During inspiration, negative pressure is created in the cuirass shell Expiration can be either passive or assisted with positive pressure (so-called biphasic ventilation) This can be applied in both the supine (A) and nonsupine (B) positions Cochrane review by Shah and colleagues suggested a decrease in need for intubation and shorter hospital stay with the use of NPV in children with acute respiratory failure.48 In 2017, a large retrospective single-center study reported the use of NPV in pediatric patients with acute respiratory failure.47 Out of 233 patients supported with NPV, 163 (70%) had resolution of acute respiratory failure while receiving NPV, while 63 patients required change to PPV modalities, including intubation NPV cuirass was removed from five patients owing to complications (gastroesophageal reflux, hypothermia, and skin bruising without sequelae) and from two other patients for transport Viral bronchiolitis was the most common diagnosis (70% of the cases), and there was a 28% reduction in intubation rate during the study period compared with the prior years NPV use via cuirass may be suitable for pediatric patients with facial deformities, facial burns, claustrophobia, severe agitation, and with oronasal secretion burden (Box 55.2) NPV is particularly useful in patients who failed extubation to avoid reintubation when there is difficulty weaning off the ventilator owing to chest wall muscle weakness Other clinical conditions in which NPV has been successfully used include acute exacerbation of cystic fibrosis, air-leak syndrome, pneumatocele, and neuromuscular weakness.53,60,61 NPV has been used in patients with congenital hypoventilation syndrome (CHS) In 1994, Hartmann and colleagues described the safe and effective use of NPV in patients with CHS with varying degrees of respiratory insufficiency This modality of respiratory support was accepted by the parents and provided a better quality of life for patients in this case series.49,62 Anecdotally, NPV has been applied to patients concomitantly receiving PPV, both while intubated or on NIV In intubated patients, the application of NPV may allow for faster and more successful weaning from PPV toward extubation This is a • BOX 55.2 Advantages, Disadvantages, and Contraindications of Negative Pressure Ventilation Advantages Contraindications Comfort Ability to speak Access to oral and nasal secretions Less need for sedation Suitable for patients with facial trauma/burns Reduced risk of aspiration Avoidance of risks of positive pressure ventilation (barotrauma, compromised venous return) Burns on the anterior chest or abdominal wall Thoracic and abdominal surgery Chest and abdominal trauma—flail chest Respiratory arrest Cardiac arrest Hemodynamic instability (shock) Moderate to severe pediatric acute respiratory distress syndrome Need for immediate intubation Rapid progression of neuromuscular illness Rapid worsening of neurologic illness Inability to clear oropharyngeal secretions Impaired gag and cough reflex Upper airway obstruction Disadvantages Cannot be used patients weighing 170 kg Cuirass fitting can be challenging in patients weighing ,4 kg Requires a patent/viable airway promising area of clinical application that warrants exploration Takeda et al have shown that application of external biphasic cuirass ventilation in patients already receiving PPV facilitates secretion clearance and supports ventilation during temporary disconnections from PPV for endotracheal tube suctioning.63 Nocturnal use of NPV might have a role in long-term management of patients with neuromuscular weakness, but further studies are warranted 650 S E C T I O N V Pediatric Critical Care: Pulmonary Negative-Pressure Ventilation Use in Chest Physiotherapy and Secretion Clearance Clearance of airway secretions can be enhanced during cuirass ventilation by using the secretion clearance mode, which allows for mobilization and expectoration of secretions while maintaining lung inflation There are two modes of NPV for airway clearance Vibration Mode This mode shakes and thins secretions It is considered a chest physiotherapy tool to enhance secretion clearance This can be set as follows: inspiratory/expiratory pressures, 28/18 cm H2O; I:E ratio of 1:1; frequency, 800 per minute; and duration, to minutes Cough Mode This mode assists with expectoration of secretions and acts as a minisustained inflation This can be set as follows: inspiratory pressure, 225 cm H2O (up to 235); expiratory pressure, 115 cm H2O (up to 125); I:E ratio of 4:1; frequency, 50 per minute; and duration, minutes The negative pressure can be made more negative as needed Completion of both modes represents one cycle of secretion clearance Each secretion clearance session should last between 30 and 60 minutes Neurally Adjusted Ventilatory Assist Neurally adjusted ventilatory assist (NAVA) is a pressure-assisted mode that uses the electrical activity of the diaphragm (EAdi) to trigger a spontaneous assisted breath and deliver inspiratory pressure in response to that activity NAVA provides ventilatory support proportional to the EAdi It also enables physiologic variations in tidal volume and inspiratory time from breath to breath NAVA detects EAdi through eight electromyogram sensors located at the distal end of a special nasogastric or orogastric tube These sensors are usually positioned near the end of the esophagus close to the gastroesophageal junction where the trunk of the phrenic nerve meets the diaphragmatic muscle NAVA has been successfully used in acute respiratory failure in both children and adults undergoing mechanical ventilation NAVA has been shown to improve ventilator synchrony in neonates and children Lower peak inspiratory pressures and Fio2 requirements have been reported during NAVA in comparison with standard conventional ventilation, along with a reduced need for sedation and shorter PICU length of stay.62,64–70 In a prospective randomized crossover study, Vignaux et al.71 reported improved patient-ventilator synchrony in infants and children with acute respiratory failure receiving NAVA during NIV In a more recent prospective study, Baudin et al described the use of NIV-NAVA in 11 infants under months of age with respiratory failure and showed a lower asynchrony index during NAVA compared with pressure assist control mode (3 3% vs 38 21%, respectively).64 Compared with pressure support ventilation, the use of NAVA improved patient synchrony during NIV in adults and lowbirthweight infants with respiratory insufficiency.69,72,73 In a recent systematic review, Beck et al reported that the use of invasive and NIV NAVA and EAdi monitoring in children is feasible and safe NAVA use improves patient-ventilator synchrony and results in lower peak inspiratory pressures when compared with conventional ventilation This results in improved patient comfort, less sedation, and decreased length of stay.62 DucharmeCrevier and colleagues reported a significantly lower total time spent in asynchrony during NIV NAVA (8%) compared with conventional NIV before (27%) and after (32%) NIV NAVA.68 Patient Selection In adults, NIV is the primary treatment of choice for acute respiratory failure due to chronic obstructive pulmonary disease and acute cardiogenic pulmonary edema.74,75 There are currently no disease processes in children for which the initial application of NIV is considered standard of care However, the successful use of NIV in parenchymal lung diseases has been described for decades Despite the lack of clinical practice guidelines supporting its routine use, NIV is likely effective in supporting pediatric patients with mild and moderate acute respiratory insufficiency.39,76–82 The primary goal of NIV is to stabilize the critically ill patient through provision of adequate gas exchange and decreased work of breathing in a disease process expected to be self-limited This is achieved by optimizing FRC, alveolar recruitment, unloading fatigued respiratory muscles, and supplementing oxygen delivery For most children with acute respiratory failure, the indications for NIV include lower respiratory tract disease and avoidance of intubation in cases in which IMV is undesirable or contraindicated (Box 55.3).77,7883–86 NIV may be considered as the initial mode of respiratory support in children expected to have a short, uncomplicated illness trajectory There are many clinical situations in which NIV is not an appropriate initial mode of respiratory support and IMV is indicated These include respiratory arrest, airway compromise (e.g., obstruction, unmanageable secretions), hypercarbia causing obtundation, respiratory failure related to neurologic illness or injury, respiratory failure associated with multiorgan failure, severe septic shock, or an anticipated prolonged course (Box 55.4) • BOX 55.3 Indications for Noninvasive Positive Pressure Ventilation Acute Lower Respiratory Tract Diseases Bronchiolitis Pneumonia Pulmonary edema Acute chest syndrome Atelectasis Pediatric acute respiratory distress syndrome Avoidance of Intubation or Reintubation Immunocompromised patients Neuromuscular disorders Cystic fibrosis Restrictive chest diseases Postoperative respiratory insufficiency Do-not-intubate status Postextubation respiratory insufficiency Long-Term Use Obstructive sleep apnea Chest wall deformities (e.g., scoliosis) Neuromuscular diseases Chronic respiratory failure (e.g., bronchopulmonary dysplasia) CHAPTER 55 Noninvasive Ventilation in the Pediatric Intensive Care Unit • BOX 55.4 Contraindications for Noninvasive Positive Pressure Ventilation Respiratory arrest Cardiac arrest Hemodynamic instability (shock) Severe pediatric acute respiratory distress syndrome Need for immediate intubation Rapid progression of neuromuscular illness Rapid worsening of neurologic status Inability to clear oropharyngeal secretions Impaired gag or cough reflex Recent esophageal or gastric surgery Uncooperative patient Severe agitation Facial trauma Basal skull fracture—cerebrospinal fluid leak Severe facial burns Untreated pneumothorax Bronchiolitis While current practice guidelines for the management of bronchiolitis lack definitive recommendations on advanced levels of respiratory support, NIV use has been reasonably well studied in this patient population.87–90 Both CPAP and HFNC have been used to improve breathing effort and prevent intubation in infants and children with bronchiolitis, with recent multicenter studies suggesting that some centers preferentially use HFNC while others routinely chose CPAP.90–92 The use of nasal CPAP for children with bronchiolitis was first reported in the early 1980s.93 CPAP improves ventilation and oxygenation by unloading the diaphragm, increasing FRC, maintaining airway patency, and supplementing oxygen.94 On the other hand, HFNC improves work of breathing through a variety of mechanisms, including overcoming some of the inspiratory resistance, improving mucociliary clearance, decreasing the energy cost associated with conditioning (heating and humidifying) the inspired gas, and replacing carbon dioxide–rich expiratory gas in the nasopharyngeal anatomic dead space with oxygen-rich gas.95 These effects are especially beneficial in bronchiolitis, given the increased dead space in infants and small children relative to adults.96 Owing to a paucity of high-quality randomized controlled trials, there is currently insufficient evidence to recommend the routine use of either CPAP or HFNC in children with bronchiolitis.30,94,97–101 Several studies have compared the two respiratory support modalities in this form of respiratory illness In one recent multicenter trial with a noninferiority design, 142 infants aged months or less with a primary diagnosis of bronchiolitis were randomized to receive nasal CPAP at cm H2O versus HFNC at flow rates of L/kg per minute The primary outcome of treatment failure within 24 hours occurred in 31% of the infants in the CPAP group and 51% of infants in the HFNC group, with the authors rejecting their initial hypothesis of HFNC noninferiority.28 However, this finding was largely related to the chosen definition of failure, since both modalities performed similarly regarding the need to escalate support (intubation), and the majority of subjects who failed CPAP were rescued by HFNC following crossover.28 A subsequent study done by the same investigators showed an HFNC failure rate similar to the CPAP failure rate in the previous study (39% vs 31%), suggesting 651 that inexperience with HFNC may have biased the first study.30 A smaller study (n 31) comparing HFNC to CPAP found no differences in outcomes and, again, HFNC was better tolerated by patients.102 Intubation rates were less than 10% for both trials and did not differ between the HFNC and CPAP groups In a recent multicenter database study including over 6000 children with bronchiolitis, those receiving NIV as initial respiratory support had higher intubation rates compared with those receiving HFNC as initial therapy (20% vs 11%, P , 001).90 While HFNC is likely better tolerated than CPAP, limited studies and concerns with trial design likely mean that more data are needed before definitive conclusions regarding the use of CPAP versus HFNC in these patients can be made.103 Bronchiolitis was the most common diagnosis (70%) in a large retrospective study describing one center’s use of NPV in pediatric patients with acute respiratory failure.47 Of the 233 included patients, 170 (70%) had resolution of acute respiratory failure while receiving NPV, while 63 subjects required a change to PPV, including intubation Complications related to the cuirass—including gastroesophageal reflux, hypothermia, and skin bruising—were rare (,5%), although enteral nutrition was delayed in one-third of patients and over half required intravenous sedation to facilitate patient-ventilator synchrony.47 Asthma Studies describing the use of NIV in children with critical asthma are limited, with most involving HFNC and BiPAP.34,104,105 The proposed mechanisms of action of HFNC, including application of low levels of PEEP and washout of carbon dioxide–rich gas in the nasopharyngeal dead space, may make HFNC an attractive option in treatment of asthma However, owing to concerns surrounding adequate drug deposition of aerosolized albuterol, clinicians should give careful consideration to initiating HFNC in a child with critical asthma who is otherwise stable or improving.106 An observational study comparing HFNC with standard oxygen suggested that children receiving HFNC had greater improvements in heart rate, respiratory rate, Spo2/Fio2 ratio, pH, and partial pressure of carbon dioxide (pCO2) They also had a higher illness severity, more use of adjunctive medications, and a longer hospital length of stay than those children receiving simple oxygen delivery.107 A single-center randomized feasibility study comparing HFNC with standard oxygen therapy included 62 children in the emergency department with an acute asthma exacerbation.108 Children treated with HFNC for hours were more likely to have improvement in the pulmonary score, an objective measure of respiratory distress, compared with those children receiving standard oxygen therapy There were no differences in secondary outcomes—including need for hospitalization, need for PICU admission, or length of stay—between the groups.108 There is significantly more evidence supporting the use of BiPAP for critical asthma A single-center study comparing the two interventions showed a higher treatment failure and longer length of stay in the HFNC group compared with the BiPAP group.109 In children with an asthma exacerbation, acute inflammation of the lower airways causes increased airway resistance, a prolonged expiratory time constant, and premature airway closure during exhalation.110 The resultant dynamic hyperinflation causes positive static recoil pressure at the end of expiration, termed autoPEEP Because of auto-PEEP, a more forceful breath accompanied by a larger drop in pleural pressure is required to induce inspiration.111 In asthma, the application of BiPAP with appropriate 652 S E C T I O N V Pediatric Critical Care: Pulmonary levels of EPAP decreases the work of breathing associated with hyperinflation and auto-PEEP One must select a level of EPAP that decreases the work of breathing while avoiding excessive pressures that could exacerbate hyperinflation In the absence of definitive studies, there are currently insufficient data to recommend routine use of NIPPV in children with critical asthma.34 While not considered standard of care, NIPPV may be employed in an attempt to decrease the need for IMV.112,113 Despite concerns regarding the safety of NIPPV use in asthma, including barotrauma,114 multiple observational studies suggest it to be safe and effective in improving the work of breathing and oxygenation.112,113,115,116 Pediatric Acute Respiratory Distress Syndrome While prospective data are limited, the use of NIV in all forms of pediatric acute respiratory failure, including PARDS, is increasing.13,82,117,118 Based on two multicenter cohort studies, the use of NIV for PARDS has increased from 8.5% in 2005 to 23% in 2016 to 2017.119,120 An observational cohort study including 31 PICUs in the United Kingdom demonstrated decreased mortality, shorter duration of ventilation, and decreased length of PICU stay associated with successful use of NIV as first-line respiratory support for pediatric acute hypoxemic respiratory failure.121 While its association with favorable outcomes makes the use of NIV an attractive alternative to IMV, appropriate patient selection is paramount because failure of NIV has been associated with higher morbidity and mortality in PARDS.120 Khemani et al described the incidence of PARDS in a prospective, cross-sectional, observational study including patients from 145 PICUs in 27 countries.120 Of the children diagnosed with PARDS, 22% were noninvasively ventilated (n 160) and half required subsequent intubation Patients who required IMV after NIV had significantly higher mortality and longer duration of ventilatory support than those children who were successfully managed with NIV The degree of hypoxemia was strongly associated with need for subsequent intubation.120 NIV is likely beneficial for children with mild PARDS when used early and judiciously PARDS is a heterogenous lung disease caused by capillary and alveolar epithelial damage, surfactant dysfunction, and diffuse alveolar damage These conditions lead to changes in respiratory resistance and compliance, causing hypoxic and hypercarbic respiratory failure Implementation of NIV can prevent alveolar collapse and recruit atelectatic lung tissue, increase the FRC, and offload the inspiratory work of breathing to improve oxygenation and ventilation in these patients.122 Another potential advantage includes avoidance of ventilatorassociated lung injury and need for sedation Although the implementation of NIV in PARDS is physiologically sound, the data supporting its use are limited Yañez et al randomized 50 children aged month to 15 years with acute respiratory failure to BiPAP or face mask oxygen Nearly half of the children in this cohort had a diagnosis of bronchiolitis Use of BiPAP was associated with a decrease in the need for subsequent intubation (28% vs 60%, P 045).123 Despite this promising outcome, children with more severe hypoxic respiratory failure are more likely to require intubation, with some studies describing a failure rate of over 50% in children with PARDS.124 Immunocompromised Patients Children with malignancy comprise an estimated 6% of all intensive care admissions.125 While overall survival has improved, mortality associated with acute respiratory failure remains high.126–129 The unfavorable outcomes associated with IMV in immunocompromised patients make consideration of NIV as a first-line respiratory support modality an attractive alternative.78,126,127,130–134 Several small randomized studies in immunocompromised adult patients suggest that early use of NIV can decrease mortality and intubation rate when compared with oxygen therapy alone.135 Pediatric data are limited In a singlecenter retrospective study including 23 immunocompromised children with acute respiratory failure, 13 (56%) children were successfully managed with NIV.136 These children had shorter ICU and hospital stays and fewer hospital-acquired infections than children managed with IMV.136 Another single-center study described clinical variables associated with NIV success and failure in a cohort of immunocompromised children.137 Among the 41 included subjects, 11 (27%) were successfully supported with NIV In this small study, lower oxygen requirements, lower Spo2/Fio2 ratio, and bacterial septicemia were predictive of NIV success, while fungal septicemia and culturenegative disease were predictive of NIV failure In a more recent large retrospective cohort study, Pancera et al reported an NIV success rate of 74.2% in 120 immunocompromised children with acute respiratory failure.138 The only randomized controlled trial to study NIV for acute respiratory failure in immunocompromised children found no evidence to support the early use of CPAP Forty-two children were randomized to either CPAP in the PICU or low-flow supplemental oxygen on the general ward There was no difference in need for intubation and mechanical ventilation between the groups, although the early CPAP group had higher mortality at 30 (33% vs 5%, P 041) and 90 (52% vs 19%, P 029) days.139 Neuromuscular Disease Children presenting to the PICU with underlying neuromuscular disease and acute respiratory failure benefit from NIV NIPPV is standard of care for children and adults with chronic respiratory failure associated with neuromuscular disease, including Duchenne muscular dystrophy and spinal muscular atrophy.140–142 Early application of NIV is also recommended during times of illness and acute worsening of their respiratory failure.142,143 For those children who require IMV, NIV has been proposed to facilitate early weaning off IMV, most commonly by implementing it preemptively after extubation following major surgical procedures.144–146 Patient Monitoring and Complications While there is limited evidence to suggest that HFNC may be safely delivered on a general inpatient ward, most children requiring noninvasive support for acute respiratory failure should be admitted to an ICU.122,136,147 Continuous monitoring of heart rate, respiratory rate, and pulse oximetry is necessary; oxygen therapy should be titrated to achieve Spo2 between 88% and 97% Arterial, venous, or capillary blood gas measurements can add further information on gas exchange to help critical care providers guide escalation of therapy as needed While lacking strong evidence to support the timing and frequency of these measurements, oxygenation indices and other gas-exchange metrics should be assessed at initiation of NIV support, within 24 hours of initiation, and serially at the discretion of the critical care providers determined by the patient’s clinical progression CHAPTER 55 Noninvasive Ventilation in the Pediatric Intensive Care Unit • BOX 55.5 Complications of Noninvasive Positive Pressure Ventilation Inadequate gas exchange Pulmonary aspiration Gastric distention and perforation Pressure sores (face, nose) Eye injury and irritation/conjunctivitis Air leak (pneumothorax, pneumomediastinum) Agitation Delay in intubation Hemodynamic monitoring during NIV in critically ill patients is important to appropriately guide fluid management therapy and avoid fluid overload Although the optimal fluid management strategy in these patients has yet to be defined, judicious use of fluids to maintain appropriate intravascular volume is recommended Monitoring urine output, capillary refill, and peripheral pulses is recommended in these critically ill patients Perhaps the most serious complication of NIV is delayed intubation in children whose respiratory compromise is failing to improve (Box 55.5) There is no consistency in the literature to support the timing and frequency of work-of-breathing and gasexchange metrics, but several studies suggest that physiologic changes within several hours of NIV initiation are predictive of failure.124,148–150 Intubation should be considered in patients receiving NIV who not show clinical improvement or have worsening of the disease process within a few hours of NIV implementation Less severe complications related to NIV use include gastric distension, aspiration, delayed enteral feeding, and pressure ulcers.151,152 Gastric distension can be mitigated with placement of a nasogastric tube, although this may prevent adequate seal of the face mask It is not known if enteral feeding during NIV increases aspiration risk in children In adults with respiratory failure supported by NIV, initiation of enteral nutrition is often delayed owing to increased risk of aspiration.153,154 A recent survey study of pediatric intensivists reports that over 90% of respondents not consider NIV a contraindication to initiation of enteral nutrition.155 This finding may not align with clinical practice, as a cross-sectional retrospective study of six PICUs showed that NIV was associated with delayed institution of enteral nutrition.156 Until more definitive data are available, clinicians must use their best judgment in deciding which patients receiving NIV are good candidates for enteral nutrition Skin breakdown and pressure ulcers can also be serious complications associated with NIV, with an incidence as high as 88% in some pediatric studies.157 Improper fit is the most important factor contributing to the development of pressure ulcers, which can be mitigated by use of a properly fitting mask and scheduled examination of the skin.158 Sedation During Noninvasive Ventilation Children may require sedation to facilitate NIV While most patients tolerate treatment with nasal CPAP and HFNC, younger children may have difficulties tolerating the tight-fitting face mask required with BiPAP3 and during NPV.47 Agitation can precipitate device asynchrony, diminishing its effectiveness and leading to barotrauma Pharmacologic sedatives and anxiolytics can be safe and effective provided that patient anxiety is not due to impending respiratory failure requiring immediate IMV 653 The ideal agent should provide appropriate anxiolysis without affecting respiratory drive, airway tone, or hemodynamics Midazolam is a central nervous system depressant that acts through inhibition of the g-aminobutyric acid neurotransmitter.159 As the most commonly used benzodiazepine in the PICU,160 midazolam possesses sedative, anxiolytic, muscle relaxant, and amnestic properties.159 It has been used successfully in children with status asthmaticus161 and infants with hypoxemic respiratory failure162 treated with NIV, although concerns regarding hemodynamic stability, preservation of airway tone and respiratory drive, and long-term neurologic morbidity may limit its use.163 Dexmedetomidine is an a2-adrenergic agonist that has experienced an increase in popularity in recent years.164 While its minimal effects on respiratory drive make it an attractive agent,165 the potential for negative effects on hemodynamics—including decreased catecholamine release,166 decreased cardiac index, bradycardia, and hypotension—should be carefully considered when initiating the medication.167 One retrospective single-center study described 202 children with acute respiratory failure due predominantly to status asthmaticus and bronchiolitis treated with NIV and concurrent dexmedetomidine infusion.168 Most patients did well, with 98% successfully weaned off NIV without need for intubation However, dexmedetomidine infusion was associated with clinically significant events, including bradycardia (13%), hypotension (20%), hypopnea (5%), and a 1-month-old infant who required cardiopulmonary resuscitation and vasoactive medications following apnea and bradycardic arrest.168 Risk of withdrawal may also be a consideration with dexmedetomidine use,169,170 although this is generally only of consequence following prolonged infusions.171 Failure of Noninvasive Ventilation Although many children are successfully treated with NIV, there is concern that inappropriate application of NIV may mask progressive worsening of respiratory failure, delay intubation, and increase the risk of associated complications, including death.172,173 Due to lack of controlled trials, there are currently no clear clinical guidelines to aid in the decision to use NIV in pediatric respiratory failure.34,94,100,105,174 Furthermore, the failure rate for NIV is variable and likely dependent on the underlying disease process and chosen mode of ventilation Appropriate patient selection and early recognition of NIV failure are especially important, as use of NIV in the pediatric population continues to increase.5,10 Evidence in favor of NIV, including reduced intubation rates, has been best established in infants with bronchiolitis receiving CPAP or HFNC.18,28,175,176 Studies demonstrating successful treatment of bronchiolitis with either modality show improvements in respiratory effort as measured by vital signs, clinical respiratory scores, and gas exchange.28,59,177,178 For infants with bronchiolitis, failure rate with use of CPAP and HFNC can be as low as less than 3%28 but as high as 50% in children with PARDS.14 Many children with PARDS, at risk for PARDS, or with acute hypoxemic respiratory failure ultimately require IMV despite initial treatment with NIV.21 In a recent prospective multicenter study, children with PARDS who failed first-line therapy with NIV had higher rates of PICU and 90-day mortality compared with children successfully managed with NIV.14 In this cohort, more severe hypoxemia at diagnosis was strongly associated with subsequent intubation NIV failure has also been associated with higher severity of illness at ... NPV for airway clearance Vibration Mode This mode shakes and thins secretions It is considered a chest physiotherapy tool to enhance secretion clearance This can be set as follows: inspiratory/expiratory... 800 per minute; and duration, to minutes Cough Mode This mode assists with expectoration of secretions and acts as a minisustained inflation This can be set as follows: inspiratory pressure, 225... through provision of adequate gas exchange and decreased work of breathing in a disease process expected to be self-limited This is achieved by optimizing FRC, alveolar recruitment, unloading