Noninvasive Positive Pressure Ventilation

Introduction Noninvasive Positive Pressure Ventilation is the delivery of assisted breaths without placement of an artificial airway Noninvasive Positive Pressure Ventilation is the delivery of assisted breaths without placement of an artificial airway Over the past decade, noninvasive positive pressure ventilation has seen increasing use to treat acute respiratory failure Over the past decade, noninvasive positive pressure ventilation has seen increasing use to treat acute respiratory failure This increase has been mostly driven by the desire to avoid complications of invasive mechanical ventilation, such as tracheal injury, VAP, and heavy sedation that may interfere with the weaning process This increase has been mostly driven by the desire to avoid complications of invasive mechanical ventilation, such as tracheal injury, VAP, and heavy sedation that may interfere with the weaning process

Methods of Delivery Currently available Methods of Delivery include: Interfaces I Interfaces I Nasal masks or pillows Nasal masks or pillows Facial masks Facial masks Both attached by means of headgear Both attached by means of headgear

Interfaces II Must be used properly To avoid air leaks,( nasal masks carry greater risk) To avoid air leaks,( nasal masks carry greater risk) Nose abrasion Nose abrasion Eye irritation Eye irritation Poor overall clinical tolerance Poor overall clinical tolerance

Interface III Full facemask seems preferable in acute setting at least during the early phase of NIV Full facemask seems preferable in acute setting at least during the early phase of NIV Seems more effective in increasing tidal volume and reducing PCO 2 Seems more effective in increasing tidal volume and reducing PCO 2 Nasal masks are usually used for: Nasal masks are usually used for: home ventilation home ventilation Less distressed patients Less distressed patients Naveilesi P., Fanfulla et al. Crit. Care Med. 2000

Methods of Delivery Many different Modalities can be delivered via NIV Ventilator Modes: Volume-Cycle Ventilation Volume-Cycle Ventilation Similar to Standard mechanical ventilation Similar to Standard mechanical ventilation Alveolar ventilation is maintained by adjusting tidal volume and respiratory rate Alveolar ventilation is maintained by adjusting tidal volume and respiratory rate

Pressure-Support Ventilation Constant positive pressure is applied during patient’s spontaneous inspiration Constant positive pressure is applied during patient’s spontaneous inspiration Tidal volume controlled by adjusting pressure- support level Tidal volume controlled by adjusting pressure- support level Tolerant of small leaks Tolerant of small leaks

Methods of Delivery Ventilator Modes II Ventilator Modes II Bi-level Positive Airway Pressure Bi-level Positive Airway Pressure Overall most widely used in ICU Overall most widely used in ICU Different levels of positive pressure during inspiration and expiration Different levels of positive pressure during inspiration and expiration IPAP / EPAP 10-20/5-10 cmH 2 O IPAP / EPAP 10-20/5-10 cmH 2 O

Greater patient tolerance, but increased incidence of aerophagia and air leakage Greater patient tolerance, but increased incidence of aerophagia and air leakage flow rate or fractional inspired oxygen concentration (FIO2) adjusted to maintain oxygen saturation at ≥ 90%. flow rate or fractional inspired oxygen concentration (FIO2) adjusted to maintain oxygen saturation at ≥ 90%. BIPAP is often used BIPAP is often used

Ventilator Modes III Face mask continuous positive airway pressure (CPAP) Face mask continuous positive airway pressure (CPAP) Simplest form of NIV Simplest form of NIV Commonly used for OSA Commonly used for OSA Generally not indicated for ARF Generally not indicated for ARF Controversial in acute lung injury Controversial in acute lung injury Can be useful in cardiogenic pulmonary edema and postoperative respiratory complications Can be useful in cardiogenic pulmonary edema and postoperative respiratory complications

1. Appropriately monitored location, oximetry, vital signs as clinically indicated 2. Patient in bed or chair at >30º angle 3. Select and fit interface 4. Select ventilator 5. Apply headgear; avoid excessive strap tension (one or two fingers under strap) 6. Connect interface to ventilator tubing and turn on ventilator 7. Start with low pressure in spontaneously triggered mode with backup rate; pressure limited: 8 to 12 cm H 2 O inspiratory pressure; 3 to 5 cm H 2 O expiratory pressure Protocol for Initiation of Noninvasive Positive Pressure Ventilation

8. Gradually increase inspiratory pressure (10 to 20 cm H2O) as tolerated to achieve alleviation of dyspnea, decreased respiratory rate, increased tidal volume (if being monitored), and good patient- ventilator synchrony 9. Provide 02 supplementation to as needed to keep 02 sat >90% 10. Check for air leaks, readjust straps as needed 11. Add humidifier as indicated 12. Consider mild sedation (e.g. intravenously administered lorazepam 0.5 mg) in agitated patients 13. Encouragement, reassurance, and frequent checks and adjustments as needed 14. Monitor occasional blood gases (within 1 to 2 hours) and then as needed Protocol for Initiation of Noninvasive Positive Pressure Ventilation Reproduced from International Consensus in Intensive Care Medicine: Noninvasive positive pressure ventilation in acute respiratory failure. Am. J. Respir Crit. Care Med. 2001,

Patient Selection NPPV has been applied in a wide variety of clinical Settings: Acute exacerbation of COPD Acute exacerbation of COPD Acute cardiogenic pulmonary edema Acute cardiogenic pulmonary edema Hypoxemic respiratory failure Hypoxemic respiratory failure Postoperative respiratory failure Postoperative respiratory failure Immunocomprised patients Immunocomprised patients Terminal patients with “do not intubate” orders Terminal patients with “do not intubate” orders Adjunct to weaning from invasive mechanical ventilation Adjunct to weaning from invasive mechanical ventilation

CONTRAINDICATIONS TO NPPV Cardiac or respiratory arrest Nonrespiratory organ failure Severe encephalopathy (e.g., GCS, 10) Severe upper gastrointestinal bleeding Hemodynamic instability or unstable cardiac arrhythmia Facial surgery, trauma, or deformity Upper airway obstruction Inability to cooperate/protect the airway Inability to clear respiratory secretions High risk for aspiration AM J Respir Crit Care Med, vol 163, 2001

Potential Benefits Metaanalyses of randomized trials of NPPV in patients with acute respiratory failure have concluded that NPPV reduces: Mortality Mortality Need for intubation and associated risks Need for intubation and associated risks Length of hospital stay and mechanical ventilation Length of hospital stay and mechanical ventilation These improvements in outcome appear to be greatest for patients with chronic obstructive pulmonary disease These improvements in outcome appear to be greatest for patients with chronic obstructive pulmonary disease and acute pulmonary edema. Liesching, T. et al. Chest 2003

Mechanism of Benefit Improved Alveolar Ventilation Improved Alveolar Ventilation Reduced work of breathing Reduced work of breathing Resting of the respiratory musculature Resting of the respiratory musculature Decreased auto-PEEP and facilitation of ventilator triggering Decreased auto-PEEP and facilitation of ventilator triggering

Goals of NPPV The goals differ depending upon the clinical content The goals differ depending upon the clinical content COPD or asthma COPD or asthma Reduce CO 2 by unloading the respiratory muscles and augmenting alveolar ventilation Reduce CO 2 by unloading the respiratory muscles and augmenting alveolar ventilation Stabilizing arterial pH Stabilizing arterial pH Hypoxemic ARF Hypoxemic ARF Ensure an Adequate PaO 2 Ensure an Adequate PaO 2

Goals of NPPV Cardiogenic Pulmonary Edema Cardiogenic Pulmonary Edema Improve oxygenation Improve oxygenation Reduce work of breathing Reduce work of breathing Increase Cardiac output Increase Cardiac output Chronic Ventilatory failure Chronic Ventilatory failure Provide sufficient oxygenation and/or CO 2 elimination to sustain life Provide sufficient oxygenation and/or CO 2 elimination to sustain life Reversing atelectasis Reversing atelectasis Resting of respiratory muscles Resting of respiratory muscles

Complications NIPPV has several potential risks. Most common: NIPPV has several potential risks. Most common: Pressure necrosis of facial skin Pressure necrosis of facial skin Cushioning the forehead and the bridge of the nose prior to mask attachment will decrease the likelihood of these problems Mild gastric distention and aspiration of gastric contents Rarely significant at routinely applied levels of inspiratory pressure support Mild gastric distention and aspiration of gastric contents Rarely significant at routinely applied levels of inspiratory pressure support Decreased sputum clearance Decreased sputum clearance Eye irritation Eye irritation

Complications Sinus pain or congestion Sinus pain or congestion Modest air leaks at the face seal Modest air leaks at the face seal Transient hypoxemia and hypercapnia Transient hypoxemia and hypercapnia Delay in intubation Adequate patient monitoring, including pulse oximetry is therefore crucial Delay in intubation Adequate patient monitoring, including pulse oximetry is therefore crucial Barotrauma is uncommon Barotrauma is uncommon Adverse hemodynamic effects are unusual Adverse hemodynamic effects are unusual

Advantages of NPPV Avoids Complications of Intubation Avoids Complications of Intubation Nosocomial pneumonia, the natural glottic barrier is preserved Nosocomial pneumonia, the natural glottic barrier is preserved Reduces need for sedation Reduces need for sedation Preserves speech Preserves speech Preserves ability to eat Preserves ability to eat Improves comfort Improves comfort

Who Should Administer NPPV and in What Location? The optimal location for patients receiving NPPV depends on: The optimal location for patients receiving NPPV depends on: Capacity for adequate monitoring Capacity for adequate monitoring Staff skill and experience Staff skill and experience Availability of resources Availability of resources Knowledge of the equipment used Knowledge of the equipment used Awareness of potential complications Awareness of potential complications Etiology of ARF Etiology of ARF

Acute exacerbation of chronic obstructive pulmonary disease is a frequent reason for hospital and ICU admission In selected COPD patients with hypercapnic respiratory failure, NPPV has shown: 28% reduction in rate of intubation when compared to patients receiving conventional care (15-40%)

Reduction in hospital LOS by 4.43 days: Reduction in hospital LOS by 4.43 days: 2.4 vs days Reduction in subsequent admission following discharge: Reduction in subsequent admission following discharge: Reduction in mortality rate, 10% Reduction in mortality rate, 10% Subgroup analysis showed that this beneficial effect occurred more in patients with severe exacerbations Subgroup analysis showed that this beneficial effect occurred more in patients with severe exacerbations Keenan, S.P. and Sinuff, T. Annals of Int. Med. 2003

Brochard, L.; Mancebo et al. conducted a prospective randomized study comparing NIPPV delivered through a facemask with standard treatment in patients admitted to five intensive care units over a 15 month period in France, Italy, and Spain Brochard, L.; Mancebo et al. conducted a prospective randomized study comparing NIPPV delivered through a facemask with standard treatment in patients admitted to five intensive care units over a 15 month period in France, Italy, and Spain 275 patients with COPD admitted to ICU 275 patients with COPD admitted to ICU 85 recruited 85 recruited 42 randomly assigned to standard therapy 42 randomly assigned to standard therapy 43 to noninvasive ventilation 43 to noninvasive ventilation

Similar characteristics on admission: Similar characteristics on admission: 11 of 43 (26%) in NIV group were intubated 11 of 43 (26%) in NIV group were intubated 31 of 42 (74%) in the standard group p < of 42 (74%) in the standard group p < Frequency of complications Frequency of complications 16% vs. 48%; P = % vs. 48%; P = Hospital Stay: Hospital Stay: 23 ± 17 days vs. 35 ± 33 days p = ± 17 days vs. 35 ± 33 days p = In hospital mortality rate In hospital mortality rate 4 of 43 patients or 9% vs. 12 of 42 patients or 29% p= of 43 patients or 9% vs. 12 of 42 patients or 29% p=0.02 New Eng. J. Med. Volume 333 (13). 1995

“In conclusion we recommend that NPPV be added to standard medical therapy for patients with severe acute exacerbations of COPD. Monitoring such patients closely in a high-dependency unit is necessary to evaluate treatment responsiveness and to facilitate endotracheal intubation if NPPV fails” Keenan S.P., Sinuff T., Annals of Int. Med. 138 (11): , June 2003

Acute Cardiogenic Pulmonary Edema Several NIV modalities have been shown to prevent the need for endotracheal intubation Several NIV modalities have been shown to prevent the need for endotracheal intubation Randomized trials comparing either CPAP or PSV and PEEP with standard medical therapy found similar results in improvements: Randomized trials comparing either CPAP or PSV and PEEP with standard medical therapy found similar results in improvements: Arterial blood gases Respiratory rates Reduced rates of endotracheal mechanical ventilation Arterial blood gases Respiratory rates Reduced rates of endotracheal mechanical ventilation

Noninvasive continuous positive airway pressure is effective in patients with Cardiogenic Pulmonary Edema Noninvasive CPAP: Noninvasive CPAP: Raises intrathoracic pressure Raises intrathoracic pressure Decreases shunting Decreases shunting Decreases venous return and preload Decreases venous return and preload Decreases afterload Decreases afterload However pts with cardiogenic pulmonary edema are vulnerable, particularly those with ischemic heart disease; appropriate drug therapy and close monitoring are needed when using any form of NIV However pts with cardiogenic pulmonary edema are vulnerable, particularly those with ischemic heart disease; appropriate drug therapy and close monitoring are needed when using any form of NIV

Until recently, most successes with NIV were obtained in patients with acute ventilatory failure and respiratory acidosis in whom hypoxemia was not the predominant feature of their respiratory failure Until recently, most successes with NIV were obtained in patients with acute ventilatory failure and respiratory acidosis in whom hypoxemia was not the predominant feature of their respiratory failure

Patients with hypoxemic respiratory failure due to pneumonia should also be considered for NPPV, provided contraindications do not exist Patients with hypoxemic respiratory failure due to pneumonia should also be considered for NPPV, provided contraindications do not exist In particular: In particular: Ability to handle secretions Ability to handle secretions Continued need for pulmonary toilette Continued need for pulmonary toilette

I In the postoperative setting, CPAP or NPPV is a reasonable option: In the postoperative setting, CPAP or NPPV is a reasonable option: improvement in pulmonary function in obese patients after gastroplasty improvement in pulmonary function in obese patients after gastroplasty reduction in intubation rates related to hypoxemia post abdominal surgery reduction in intubation rates related to hypoxemia post abdominal surgery Reduced need for invasive mechanical ventilation and reduced mortality post lung resection (21% vs 50%) and (12.5% vs. 37.5%) respectively, compared with oxygen therapy. Reduced need for invasive mechanical ventilation and reduced mortality post lung resection (21% vs 50%) and (12.5% vs. 37.5%) respectively, compared with oxygen therapy. Critical Care Med, Vol. 33(11), Nov.2005

NPPV has also been evaluated in immunocompromised hosts with respiratory failure AIDS with PCP pneumonia AIDS with PCP pneumonia Cancer Patients with neutropenia and bil. infiltrates Cancer Patients with neutropenia and bil. infiltrates Solid organ transplant recipients Solid organ transplant recipients Elderly Patients Elderly Patients

The use of NPPV in patients who have decided to forego intubation (DNR-DNI) has aroused controversy  Some have suggested that NPPV should be used in these patients or at least be offered to them  Others feel that the use of NPPV in this population of patients would be inappropriate

NPPV is effective in: NPPV is effective in: Lessening dyspnea Lessening dyspnea Alleviate respiratory distress Alleviate respiratory distress Allowing autonomy Allowing autonomy Allowing continuous verbal communication Allowing continuous verbal communication

“NPPV offers a dignified and comfortable ventilatory approach and should be considered in the management of terminally ill patients who appear to have reversible causes of acute respiratory failure.” “NPPV offers a dignified and comfortable ventilatory approach and should be considered in the management of terminally ill patients who appear to have reversible causes of acute respiratory failure.” Crit. Care Med. 2004

What is the Role of NPPV in facilitating Weaning from Mechanical Ventilation? NPPV has effectively been shown in different studies to facilitate weaning in COPD patients and prevent reintubation, especially if applied early.

NIV permits earlier removal of the ET tube than with conventional PSV and reduces the duration of daily ventilatory support, without increasing the risk of weaning failures. NIV permits earlier removal of the ET tube than with conventional PSV and reduces the duration of daily ventilatory support, without increasing the risk of weaning failures.

Conclusion There is strong evidence supporting the use of noninvasive positive pressure ventilation in several clinical settings. There is strong evidence supporting the use of noninvasive positive pressure ventilation in several clinical settings. The success of NPPV is critically dependent on careful patient selection. The success of NPPV is critically dependent on careful patient selection.