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Non Invasive Ventilation(NIV) Modaresi.MD Pediatric Pulmonologist Children’s Medical Center Tehran University of Medical Sciences WHAT IS NIV? • NIV – non-invasive ventilation is a broad term for any ventilation therapy without using an invasive artificial airway (endotracheal tube or tracheostomy tube). • But applied in a non-invasive way, e.g. via a mask, nasal prongs or a helmet. • NIV, or NPPV (Non-invasive Positive Pressure Ventilation), is also very often referred to as “mask ventilation”. History • Rudimentary devices of continuous positive airway pressure were described in the 1930s, • Negative pressure NIV was used extensively during the major poliomyelitis epidemics of the 1950's, • positive pressure NIV has become the accepted technique over the past twenty years • The major evolution of NIV from the late 1980's and early 1990's to the present day. • NIV uses in the acute and chronic respiratory failure, in both the home setting and in the critical care unit. Dräger iron lung model E 52 with electric drive (1952) Non-invasive Ventilation – A century of experience The Dräger pulmotor in use. NIV ventilation with Carina NIV benefits • Can preserve: – normal swallowing, feeding, and speech. – Cough and physiologic air warming and humidification • Can often eliminate: – injury to the vocal cords or trachea – and lower respiratory tract infections. Noninvasive Positive-Pressure Masks 1. The nasal mask (left) covers the nose but not the mouth. 2. The nasal pillows (center) insert into the nares and are held in place by a strap 3. The face mask (right) covers both the nose and the mouth. MODES OF NIV • Noninvasive positive-pressure ventilation can be given by 1. a volume ventilator, 2. a pressure-controlled ventilator, 3. a bilevel positive-airway-pressure (bilevel PAP) ventilator, or 4. a continuous-positive-airwaypressure (CPAP) device MODES OF NONINVASIVE POSITIVE-PRESSURE VENTILATION • Volume mechanical ventilation – Usually breaths of 250–500 ml (4–8 ml/kg) – Pressures vary • Pressure mechanical ventilation – Usually pressure support or pressure control at 8–20 cm of water – End-expiratory pressure of 0–6 cm of water – Volumes vary • Bilevel positive airway pressure (bilevel PAP) – Usually inspiratory pressure of 6–14 cm of water and expiratory pressure of 3–5 cm of water – Volumes vary • Continuous positive airway pressure (CPAP) – Usually 5–12 cm of water – Constant pressure, volumes vary Types of noninvasive positivepressure ventilation • NPPV has two major modes of supplying support: 1. Bilevel positive airway pressure (BiPAP) or 2. Continuous positive airway pressure(CPAP). Bilevel positive airway pressure • high-flow positive airway pressure that cycles between high-positive pressure and low-positive pressure. • In the spontaneous mode, BiPAP response to the patient’s own flow rate and cycles between high-pressure inspiration and low-pressure exhalation. • BiPAP reliably senses the patient’s breathing efforts • When inspiration is detected the inspiratory pressure is known as inspiratory positive airway pressure (IPAP). BiPAP • EPAP prevents airway and alveolar collapse, prevents atelectasis, and maintains functional residual capacity at increased levels. – EPAP maintains oxygenation, • IPAP augments tidal volume, increases airway pressure, and decreases fatigue. • BiPAP is similar to pressure support ventilation. • With BiPAP,supplemental oxygen is diluted by the high flow of air through the system. – Thus, patients may require higher oxygen flows for BiPAP for nasal cannula. • Devices using a common inspiratory and expiratory line can cause rebreathing of exhaled gases and persistent hypercapnia Continuous positive airway pressure • CPAP provides continuous positive pressure throughout the respiratory cycle, • CPAP is only effective for spontaneous breathing. • CPAP cannot provide ventilation for patients who have apnea. • When used with a nasal mask, low pressures (5 cm H2O) are effective in splinting the upper airway and preventing upper airway obstruction. • During CPAP, airway pressure remains positive during the entire respiratory cycle. • CPAP works by applying pressure though the airways at high enough levels to keep the upper airway patent, acting as a splint. Patients selection • Noninvasive positive-pressure ventilation works : – best if the patient is relaxed – less effective if the patient is anxious, uncooperative, or fighting the ventilator. Preparation of patients is critical. Patients selection for NIV • Inclusion criteria – Acute or chronic respiratory failure – Acute pulmonary edema – Chronic congestive heart failure with sleep-related breathing disorder • Relative contraindications – Failure of prior attempts at noninvasive ventilation – Hemodynamic instability or life-threatening arrhythmias – High risk of aspiration – Impaired mental status – Inability to use nasal or face mask – Life-threatening refractory hypoxemia (PaO2 60 mm Hg with 1.0 FIO2) Bilevel PAP adjust setting • it is best to start at low pressures and gradually increase the inspiratory pressure (usually to 8 to 14 cm of water) and the endexpiratory pressure (usually to 4 to 6 cm of water). • Clinical effectiveness can be determined by : 1. By palpating the sternocleidomastoid muscle to see whether its use has decreased, 2. By determining that lower thoracic expansion has increased 3. By blood gas values have improved Patient monitoring 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. their comfort, level of dyspnea, respiratory rate oxyhemoglobin saturation. signs of ventilator–patient asynchrony, nasal-mask intolerance, serious air leaks, gastric distention, drying of the eyes facial-skin breakdown,especially at the bridge of the nose. – Gastric distention is very unlikely with pressure-support levels lower than 25 cm of water. 11. Eye irritation or conjunctivitis has been reported in 16 percent of patients. 12. Facial-skin necrosis has been reported in 2 percent to 18 percent 13. Intrinsic PEEP – is often present in patients with COPD and can require much respiratory effort to trigger the ventilator. – This can be alleviated by the addition of external PEEP. Failure of NIV • noninvasive ventilation techniques are not always successful. 1. Hemodynamic instability, 2. deteriorating mental status, 3. And increasing respiratory rate. 4. Increasing respiratory acidosis, 5. the inability to maintain adequate oxyhemoglobin saturations, 6. and problems with respiratory secretions 7. Some patients are unable to tolerate or refuse to use the selected device. In general • Noninvasive ventilation should not be used in patients: 1. Who are unable to cooperate 2. Who have impaired consciousness, 3. Who have problems with retained secretions, 4. Who have hemodynamic instability. APPLICATIONS OF NONINVASIVE POSITIVEPRESSURE VENTILATION • Chronic Respiratory Failure • Acute Respiratory Failure • Congestive Heart Failure Chronic Respiratory Failure • NIV is commonly used at night for management of chronic respiratory failure. • useful in the long term management of neuromuscular disease. • NIV during sleep significantly improves: 1. daytime arterial-blood gases, 2. lung volumes 3. respiratory-muscle strength 4. reduces the number of hospitalizations of patients with respiratory insufficiency due to severe kyphoscoliosis. 5. nighttime oxygen desaturation and hypoventilation in patients with chest-wall diseases but without daytime respiratory failure. 6. support in neuromuscular diseases Chronic Respiratory Failure • in patients with intrinsic lung disease and marked hypercapnia (e.g., partial pressure of carbon dioxide greater than 60 mm Hg). • Short term for a few hours per day improves the respiratory pattern and blood gases in patients with stable COPD who have chronic hypercapnia. • improvements in 1. quality-of life measures, 2. sleep, 3. Pao2 4. Paco2 after three months of positive-pressure ventilation. • However, many patients with severe chronic COPD do not tolerate long-term bilevel PAP. • Noninvasive ventilation can be helpful in some patients with intractable Dyspnea. Neuromuscular weakness • Neuromuscular diseases, such as poliomyelitis, often were treated with the negative-pressure ventilators for respiratory failure management. • Now, NPPV, particularly BiPAP and CPAP, are the first choice of ventilatory support for patients with upper airway dysfunction and chronic respiratory failure caused by neuromuscular diseases. • NPPV ameliorates decline in lung function, improves gas exchange and cognitive function, and improves overall survival in patients who have neuromuscular disease . • For patients who have chronic progressive neuromuscular disease, noninvasive ventilation often is initiated at night for 6 to 8 hours once forced vital capacity is less than 50% of predicted. Duration is increased as respiratory muscle failure progressively worsens. • Acute NPPV – the helmet requires further evaluation – early response to NPPV predicts success • Long term NPPV – Bilevel PAP is not superior to CPAP for OSA – NPPV may be proposed in case of isolated nocturnal hypoventilation in patients with NMD – long term NPPV may be associated with a stabilisation of the decline in lung function in patients with advanced CF lung disease Sleep-disordered breathing in infants with achondroplasia 12 infants with achondroplasia and 12 healthy controls aged < 3 months Ednick et al. J Pediatr 2009;155:510 NPPV as an alternative to tracheotomy in infants with Pierre Robin sequence 7 infants with PRS mean age 3.7 ± 3.9 months Leboulanger et al. Pediatrics, accepted for publication Acute Respiratory Failure • Noninvasive positive-pressure ventilation is an effective means of treating patients with ARF due to a variety of causes. • Most used inspiratory pressures of 12 to 20 cm of water and expiratory pressures of 0 to 6 cm of water • Excluded patients with: 1. 2. 3. 4. hemodynamic instability, uncontrolled arrhythmias, gastrointestinal bleeding, a high risk of aspiration. NIV For Acute Severe Asthma 15 pts received NIV (face mask) Excluded if: Hypoxemic or hypotensive Ischemia or arrhythmia Coma or seizures No inclusion criteria listed Meduri et al, Chest ‘96, 110: 767 Obstructive sleep apnea syndrome • Present in 2 - 3% of children • Polysomnography sleep- related, obstructive/mixed apneas – with alveolar hypoventilation and – repeated arousals • Often, only partial obstruction in children = obstructive hypoventilation Benign snoring ? • Recent studies morbidity can be found in primary snorers with normal PSG question : does « benign snoring » exist in children ? Diagnosis of OSDB in children Treatment of OSDB Lipton AJ, Sleep Med Rev 2003 Schechter M, Pediatrics 2002 Praud J-P, Pediatr Pulmonol 2008 Adenotonsillecto my • Indicated in virtually all children with OSDB • Recent studies residual abnormal AHI frequent +++ – 50% - 75% children (≈ 1000 children) – ethnic minorities, obesity, family history of OSDB, severe OSAS, age > 7 years, chronic asthma, malformations, associated anomalies (Down Sd) Tauman R, J Pediatr 2006; Guilleminault C, Otolaryngol Head Neck Surg 2007; Costa DJ, Otolaryngol Head Neck Surg 2009; Bhattacharjee R, Am J Respir Crit Care Med 2010. Beyond AT Praud J-P, Pediatr Pulmonol, 2008 • CPAP • Anti-inflammatory agents – Glucocorticoids – Montelukast • Orthodontic treatments • Others … – Maxillo-facial surgery – Tracheotomy – Obesity – Gastro-esophageal reflux – Allergies Nasal C P A P • Traditionally, to avoid tracheotomy in cervico-facial malformations, Down syndrome, obesity, … • More recently, advocated after A&T, if residual anomalies Kheirandish L, Pediatrics 2007 Nasal CPAP in children not a simple task! • Equipment is mainly made for adults • Acceptance and adherence to CPAP are an important problem, especially in young children and adolescents – Facial mask sometimes better accepted – BiPAP sometimes better accepted; indications vs. CPAP unclear Koontz KL, Sleep 2003; O’Donnell, Sleep 2006; Marcus CL, Pediatrics 2006 Respiratory care in SMA Consensus statement for standard of care in spinal muscular atrophy J Child Neurol 2007; 22:1027 Chang CH et al Assessment of respiratory function Home ventilation in SMA patients Home ventilators Nocturnal, non-invasive ventilation • BiPAP are often preferred over volume preset ventilators for nocturnal non-invasive ventilation – Cheap, efficient, robust and easy to use Home ventilators Nocturnal, non-invasive ventilation • Portable volume ventilators are preferred by some experts, especially for infants / toddlers up to 20 kgs • Volume or Pressure Assist/Control mode, pressure support (LTV) Alarms, but more expensive, more complex to use PLV 102 Respironics LTV series Carefusion Interfaces for infants Nasal masks = first choice. Facial masks are alternatives Paediatric concept Infant 0-4 months 2 sizes (Maskmedic) Sullivan Infant bubble Mask From a few months (Resmed) Interfaces for infants / toddlers Nasal masks = first choice. Facial masks are alternatives MiniMe Nasal mask Infants, toddlers (Carefusion) Small Child Profile Lite Nasal Mask > 1 year / 7 kgs (Respironics) Interfaces for children Nasal masks = first choice. Facial masks are alternatives Youth Profile Lite Mask (Respironics) Mirage Micro for Kids (Resmed) Mirage Kidsta Pediatric > 7 years (Resmed) Home ventilators Diurnal, non-invasive ventilation • BiPAP ventilators + mask ventilation – Can be used during naps – Less practical for awake NIV (reading, speaking) • Volume ventilators – + mask ventilation : allows for air stacking during manually-assisted cough – + mouthpiece Patient takes a breath only when needed Allows social activities, such as eating and speaking 24h/24 NIV with daytime mouthpiece Toussaint M, Eur Respir J 2006; JR Bach, Chest 2000 • Volume ventilator + mouthpiece • normalization of diurnal TcPCO2 • Decrease in diurnal symptoms, including swallowing impairment • Increased quality of life Congestive Heart Failure • Noninvasive CPAP has been shown an effective therapy for acute pulmonary edema, improving oxygenation an A new interface: the helmet Piastra et al. Pediatr Anesthesia 2005;15:699 Alterations to noninvasive ventilation • Alterations to noninvasive ventilation are made with 1. intolerance to the BiPAP machine, 2. deterioration of consciousness and mental status, 3. if the patient and family wishes to withdraw treatment if used as a comfort measure. The duration of the NPPV requirement is variable Side effects • nasopharyngeal symptoms include increased congestion or rhinorrhea, – these effects are related to inflammatory mediators and reduced humidity of inspired gas. – Humidification of delivered gas may improve this symptom. – Clinicians also may prescribe topical nasal steroids or ipratropium nasal spray to treat nasal complaints associated with noninvasive therapy. • poorly fitting mask, including skin breakdown and air leaks. – Air leaks directed toward the eyes are associated with conjunctivitis. – Local skin reactions to the interface are also very common. – air leaks may disrupt sleep. • chest and ear discomfort, as well as exhalation discomfort associated high pressures. There are no known reports of barotraumas caused by NPPV. Long-term CPAP benefits 1. 2. 3. 4. 5. 6. 7. 8. 9. Eliminating snoring, apnea, and insomnolence, Improves of Mood, psychological function, and intellectual function improves. Testosterone and somatomedin levels normalize. Sexual function has improved. Right-sided heart failure,hypertension, and left ventricular dysfunction have improved Long-term follow-up has demonstrated no deleterious effects on lung function Sleep apnea, however, declines, and respiratory function improves over the first 3 to 12 months then stabilized Swelling, erythema, and edema caused by mechanical effects of snoring revolve during treatment, Improvement in respiratory drive may occur. Weight loss. – Many patients find it easier to lose weight while undergoing CPAP because of less fatigue and increased activity during the day. Patients must be watched for? • for signs of ventilator asynchrony 1. nasal mask intolerance, 2. serious air leaks, 3. gastric distention, 4. ocular drying, 5. facial skin breakdown, especially at the nasal bridge. Mask interface • To optimize the fit and comfort, the type of mask (nasal or full face mask) that is used depends on the patient’s facial features. • A mask that fits properly is crucial in minimizing air leaks and maximizing noninvasive ventilation efficiency. • Recommendations for evaluating different sizes and types of masks at the bedside are important to select the best fit for each patient. • When the nasal mask is used, the chinstrap decreases air leakage from around the mouth. • In patients who require prolonged intermittent mechanical ventilation for ventilatory support, rotating the use of different types of mask may decrease these problems. • • • • • • • Physiologic effects of noninvasive ventilation NPPV improves gas exchange of respiratory mechanics and relieves dyspnea in acute and chronic respiratory patients. These improvements in physiological parameters may be seen as early as 30 to 60 minutes after initiating use. Sustained daytime improvement in oxygenation and spontaneous alveolar ventilation may be documented after several weeks of NPPV used 4 to 8 hours per day. In acute respiratory failure, the mechanism of improving oxygenation is unclear but appears to be caused by increased functional residual capacity during CPAP just like PEEP improves the oxygenation during conventional mechanical ventilation. With the decreases in PaCO2 using NPPV caused by increased alveolar ventilation, especially when enough inspiratory pressure is used, NPPV restores respiratory center sensitivity to carbon dioxide, providing overall readjustment and spontaneous ventilation to maintain eucapnia. an increased ventilatory response to carbon dioxide in patients with COPD after 6 months Another possible explanation for improved gas exchange is that noninvasive ventilation may be ventilation and perfusion mismatching because of collapse of the alveolar lung units.