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No onvasive mechanical ventilation

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Hypercapnic Respiratory Failure:

Hypercapnic Respiratory Failure Francisco De Jesus, M.D. Harlem Hospital Center

Hypercapnic Disorders:

Hypercapnic Disorders Hypercapnia: PaCO 2 ≥ 45 mm Hg Hypercapnic respiratory failure: hypercapnia plus acidosis Acute: no or minimal metabolic compensation Chronic: appropriate metabolic compensation

Causes of Hypercapnic Resp. Failure:

Causes of Hypercapnic Resp. Failure Neural & Neuromuscular Brain Drugs Motor neurons Neuromuscular junction Respiratory muscles Chest Wall Kyphoscoliosis Ankylosing spondylitis Flail chest “Medical” Diseases COPD Severe asthma Late stage interstitial lung disease Pulmonary edema Sleep apnea / obesity-hypoventilation Hypothyroidism Environmental – Industrial, Natural Iatrogenic - Drugs, Ventilators

Pickwickian Syndrome:

Pickwickian Syndrome Little boy who would always fall asleep

Obesity Hypoventilation Syndrome (OHS):

Obesity Hypoventilation Syndrome (OHS) Definition BMI > 30 kg/m 2 Awake arterial pCO2 > 45 mm Hg No other causes for hypercapnia

OHS in Hospitalized Patients:

OHS in Hospitalized Patients Studied 4332 admissions to medical services 277 (6%) were severely obese (BMI > 35 kg/m 2 ) OHS present in 31% with severe obesity Mean pCO 2 of 52 ± 7 vs 37 ± 6 mm Hg in subjects with simple obesity When BMI > 50 kg/m 2 , prevalence OHS was 48% Nowbar et al., Am J Med 2004 Dark bars OHS, light bars simple obesity

Prevalance OHS Among OSA:

Prevalance OHS Among OSA Obesity hypoventilation syndrome (OHS) among subjects with obstructive sleep apnea (OSA) Prevalence of 20-30% Predictors of OHS: Serum bicarbonate level (P < 0.001) Apnea hypopnea index (P = 0.006) Lowest oxygen saturation during sleep (P < 0.001) Threshold bicarbonate level of 27 mEq/l: Sensitivity 92% Specificity 50% Mokhlesi et al., Sleep Breath, 2007

US President with Probable OSA:

US President with Probable OSA He frequently fell asleep "in the middle of the day’s business -- at his desk, at a public affair, or while signing commissions.“ Publicly, he slept at the opera, at funerals, and, "invariably," in church. He fell asleep while playing cards, and while sitting upright in his car, even an open car on Fifth Avenue in New York City. On a cross-country drive "his great bulk would lunge from side to side as the car turned or jolted over street-car tracks and crossings, yet he would never wake.“ He could sleep while standing. Who is this?

US President with Probable OSA:

US President with Probable OSA He frequently fell asleep "in the middle of the day’s business -- at his desk, at a public affair, or while signing commissions.“ Publicly, he slept at the opera, at funerals, and, "invariably," in church. He fell asleep while playing cards, and while sitting upright in his car, even an open car on Fifth Avenue in New York City. On a cross-country drive "his great bulk would lunge from side to side as the car turned or jolted over street-car tracks and crossings, yet he would never wake.“ He could sleep while standing. Who is this?

US President with Probable OSA:

US President with Probable OSA He frequently fell asleep "in the middle of the day’s business -- at his desk, at a public affair, or while signing commissions.“ Publicly, he slept at the opera, at funerals, and, "invariably," in church. He fell asleep while playing cards, and while sitting upright in his car, even an open car on Fifth Avenue in New York City. On a cross-country drive "his great bulk would lunge from side to side as the car turned or jolted over street-car tracks and crossings, yet he would never wake.“ He could sleep while standing.

Management of Hypercapnia:

Management of Hypercapnia Is it acute or chronic or acute on chronic? What is the underlying etiology? Treatment options Specific therapy for underlying cause No mechanical ventilation Non-invasive mechanical ventilation Invasive mechanical ventilation

INDICATIONS :

INDICATIONS COPD. Acute exacerbation/domiciliary. Cardiogenic pulmonary edema. Bronchial asthma Post extubation RF

Mechanical Ventilation for Acute Hypercapnic Respiratory Failure:

Mechanical Ventilation for Acute Hypercapnic Respiratory Failure Intubation with conventional mechanical ventilation Non-invasive positive pressure ventilation (NPPV)

Criteria for Non-Invasive Ventilation in COPD:

Selection criteria (at least two should be present) Moderate to severe dyspnea with use of accessory muscles and paradoxical abdominal motion Moderate to severe acidosis (pH 7.30-7.35) and hypercapnia (PaCO 2 45-60 mm Hg) Respiratory frequency > 25 breaths/min Pauwels et al, Am J Resp Crit Care Med 163: 1256, 2001 Criteria for Non-Invasive Ventilation in COPD

Criteria for Non-Invasive Ventilation in COPD:

Criteria for Non-Invasive Ventilation in COPD Exclusion criteria (any may be present) Respiratory arrest Cardiovascular instability (hypotension, arrythmias, MI) Somnolence, impaired mental status, uncooperative patient High aspiration risk Viscous or copious secretions Recent facial or gastroesophageal surgery Craniofacial trauma Fixed nasopharyngeal abnormalities Extreme obesity Pauwels et al, Am J Resp Crit Care Med 163: 1256, 2001

Masks for Non-Invasive Ventilation:

Masks for Non-Invasive Ventilation Types of mask Nasal More comfortable Patient can eat Minimal aspiration risk Communication easier Whole face No entrainment of room air May allow better ventilation Choice of mask Hypercapnic respiratory failure Nasal mask often sufficient Sometimes need whole face mask Hypoxic respiratory failure Always need whole face mask

Ventilator Devices for Non-Invasive Ventilation:

Ventilator Devices for Non-Invasive Ventilation Types of Ventilator Devices BiPAP Simple BiPAP – oxygen set by liter flow Advanced BiPAP – can set FiO2 Conventional Ventilator Choice of Ventilator Device Hypercapnic respiratory failure Simple BiPAP is sufficient Any of above may be used Hypoxic respiratory failure Need advanced BiPAP or conventional ventilator

Inspiratory and Expiratory Pressures:

Inspiratory and Expiratory Pressures Hypercapnic respiratory failure Inspiratory pressure typically in 12 to 20 cm H 2 O range Lower values better tolerated Higher values give better ventilation Expiratory pressure not really needed Except: many BiPAP machines require several cm H 2 O to function properly Hypoxic respiratory failure Inspiratory pressure typically in 12 to 20 cm H 2 O range Expiratory pressure gradually increased to improve oxygenation

PowerPoint Presentation:

Nasal Cone shaped clear plastic device with soft cuff Multiple sizes and shapes Chronic application Better tolerated by patients with claustrophobia Exert pressure over the bridge of the nose

PowerPoint Presentation:

Avoided by Fore head spacer Nasal mask with gel seal Mini-masks Custom-molded individualized masks Thin plastic flap Nasal pillows (pledgets directed to the nostrils)

PowerPoint Presentation:

Oronasal ( full face mask) Preferred in acute settings for patients with copious air leaking through the mouth For edentulous patients Interferes with speech, eating and expectoration Increase risk of aspiration, rebreathing Increase likelihood of claustrophobic reaction Total face mask (hockey goalie‘s mask)

PowerPoint Presentation:

Mouth pieces Provides NIPPV to patients with chronic respiratory failure Simple inexpensive Nasal air leaking decrease its efficacy Managed by increasing ventilator‘s tidal volume Occluding nostrils with cotton pledgets or nose clips

Ventilators for NIPPV:

Ventilators for NIPPV CPAP Delivers constant pressure during both inspiration and expiration Increase functional residual capacity Improve lung compliance Open collapsed alveoli Improve oxygenation Decrease work of breathing Decrease left ventricular transmural pressure, ↓ afterload and ↑COP Simple, small and cheap portable units are available

PowerPoint Presentation:

Pressure limited ventilators PCV Delivers time- cycled preset inspiratory and expiratory pressures with adjustable I/E ratio Permits patient triggering with a back up rate PSV Assist spontaneous breathing Peak inspiratory and expiratory pressures are selected Close matching with patient‘s spontaneous breathing Allow patient to control rate and inspiratory duration Portable devices (bilevel devices)

PowerPoint Presentation:

Volume limited ventilators V t is usually set higher (10→ 15ml/kg ) Usually set in the A/C mode, RR set slightly below the patient’s rate Portable devices are more convenient, cheap, have more sophisticated alarm system, generate high pressure

Negative pressure ventilation:

Negative pressure ventilation Intermittently apply a sub atmospheric pressure to the chest wall and upper abdomen. Efficiency depends on chest wall and abdomen compliance and surface area over which negative pressure is applied

Goals of NIV:

Goals of NIV Short term (acute) Relieve symptoms Reduce work of breathing Improve or stabilize gas exchange Good patient-ventilator synchrony Optimize patient comfort Avoid intubation Minimize risk Long term (chronic) Improve sleep duration and quality Enhance functional status Prolong survival Maximize quality of life

PROTOCOL FOR INITIATION OF NIV:

PROTOCOL FOR INITIATION OF NIV Appropriately monitored location Patient in bed or chair sitting at > 30-degree angle Select and fit interface Select ventilator Apply headgear; avoid excessive strap tension encourage patient to hold mask Connect interface to ventilator tubing and turn on ventilator

PowerPoint Presentation:

Start with low pressures/volumes in spontaneously triggered mode with backup rate; pressure-limited: 8 to 12 cm H2O inspiratory; 3 to 5 cm H2O expiratory, volume-limited: 10 ml/kg Gradually increase inspiratory pressure (10 to 20 cm H2O) or tidal volume (10 to 15 ml/kg) as tolerated to achieve alleviation of dyspnea, decreased respiratory rate, increased tidal volume , and good patient-ventilator synchrony Provide O2 supplementation as needed to keep O2 sat > 90%

Uses of NIV:

Uses of NIV Respiratory failure Hypercapnic respiratory failure Obstructive diseases Restrictive diseases Hypoxic respiratory failure Acute pulmonary edema Acute pneumonia ARDS Trauma

PowerPoint Presentation:

Imunocomprimized patients Avoid ETT→ ↓infectious and hemorrhagic complications Morbidly obese patients used in obstructive sleep apnea Do not intubate patients ETT is contraindicated or postpond Refuse intubation Post operative patients Avoid reintubation if RF develops Improve gas exchange and pulmonary function Weaning and extubation Before meeting extubation criteria

Adverse effects and complications of NIV :

Adverse effects and complications of NIV Mask related Nasal pain Nasal bridge erythema and ulceration Ventilator air flow or pressure complications Conjunctival irritation Sinus or ear pain Nasal or oral dryness Nasal congestion or discharge Gastric insufflation

PowerPoint Presentation:

Failure of NIV Mask intolerance Failure to improve ventilation Claustrophobia Sensation of excessive air pressure Patient-ventilator asynchrony MI Specially with BIPAP

COPD – Non-Invasive Ventilation:

COPD – Non-Invasive Ventilation Total of 85 patients with COPD exacerbation from five hospitals in France, Italy and Spain Non-invasive ventilation Face mask with foam inside to reduce dead space Pressure support ventilator system with back-up rate Inspiratory pressure 20 cm H 2 O, no expiratory pressure Oxygen to achieve saturation > 90% At least 6 hours/day, up to 22 hours/day if needed Brochard et al., NEJM 333:817, 1995

COPD – Non-Invasive Ventilation:

COPD – Non-Invasive Ventilation Reduced need for intubation Non-invasive group 26% intubated (11/43) Conventional group 74% intubated (31/42) (P < 0.001) Reduced complication rate Non-invasive group 16% (7/43) Conventional group 48% (20/42) (P = 0.001) Improved survival to hospital discharge Non-invasive group 91% (39/43) Conventional group 71% (30/42) (P = 0.02) Brochard et al., NEJM 333:817, 1995

Meta-Analysis: COPD and Non-Invasive Ventilation:

Lightowler et al., BMJ 326:185, 2003 Other significant outcome improvements with non-invasive ventilation in COPD Reduced rate of complications Reduced hospital length of stay Improved pH, pCO2 and respiratory rate within one hour of initiation Meta-Analysis: COPD and Non-Invasive Ventilation

Ventilation for Chronic Hypercapnia:

Ventilation for Chronic Hypercapnia Clear role for chest wall and neuromuscular disease, and congenital central hypoventilation syndrome Often used for obesity-hypoventilation with sleep apnea (ie use BiPAP rather than CPAP) Controversial for obstructive lung diseases For neuromuscular diseases, often able to start with nocturnal only, and then move to 24 hours/day with disease progression Non-invasive ventilation generally preferred over invasive ventilation, unless prominent bulbar problems or subject completely dependent on ventilator (eg. high spinal cord injury)

Long-Term Non-Invasive Ventilation and Restrictive Disorders:

Long-Term Non-Invasive Ventilation and Restrictive Disorders American College of Chest Physicians Guidelines, 1999

Examples of People Undergoing Long Term Mechanical Ventilation:

Examples of People Undergoing Long Term Mechanical Ventilation Christopher Reeve Stephen Hawking 1995 to 2004 ~1985 to present

PowerPoint Presentation:

The End

How does NIV work? :

How does NIV work? Reduction in inspiratory muscle work and avoidance of respiratory muscle fatigue Tidal volume is increased CPAP counterbalances the inspiratory threshold work related to intrinsic PEEP. NIV improves respiratory system compliance by reversing microatelectasis of the lung.

COPD EXACERBATION: NIV:

COPD EXACERBATION: NIV success rates of 80-85% increases pH, reduces PaCO2, reduces the severity of breathlessness in first 4 h of treatment decreases the length of hospital stay Mortality, intubation rate—is reduced GOLD 2003

CRITERIA FOR NIV IN ACUTE EXACERBATION OF COPD :

CRITERIA FOR NIV IN ACUTE EXACERBATION OF COPD GOLD 2005

Cardiogenic Pulmonary edema:

Cardiogenic Pulmonary edema sufficiently high level evidence to favor the use of CPAP there is insufficient evidence to recommend the use of BiPAP, probably the exception being patients with hypercapnic CPE.

Criteria to discontinue NIV:

Criteria to discontinue NIV Inability to tolerate the mask because of discomfort or pain Inability to improve gas exchange or dyspnea Need for endotracheal intubation to manage secretions or protect airway Hemodynamic instability ECG – ischemia/arrhythmia Failure to improve mental status in those with CO2 narcosis.

PowerPoint Presentation:

Eur Respir J 2002; 20:

PowerPoint Presentation:

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