Keeping Patients Off the Vent: Bilevel, HFNC, Neither? Robert Kempainen, MD Pulmonary and Critical Care Medicine Hennepin County Medical Center University of Minnesota School of Medicine
Objectives Summarize the evidence supporting use of bilevel noninvasive (NIV) and high flow nasal canula (HFNC) in acute respiratory failure Select optimal ventilatory support mode in a variety of clinical scenarios Recognize contraindications to noninvasive support
Case One 64 y.o. man with COPD presents with progressive dyspnea, cough, and sputum production over preceding 2 days. Baseline meds: tiotropium, budesonide/formoterol, albuterol prn Received duoneb via EMS and again upon ED arrival BP 160/92, HR 102, RR 28, afeb, O 2 sat 95% on 4 L/min NC Somnolent. Confused but opens eyes and withdraws with painful stimulation BS bilaterally with expiratory wheezes and accessory muscle use ABG: ph 7.16, PaCO 2 80, PaO 2 68
Should this patient be placed on bilevel noninvasive ventilation (NIV)?
Bilevel NIV in COPD Reduces intubation rate and mortality!!! Select for moderate and severe exacerbations Acute or acute on chronic respiratory acidosis (ph 7.25 7.35) Elevated respiratory rate (> 25-30) Moderate to severe dyspnea How about sicker patients like this one? ATS/ERS 2017 Guidelines: We recommend a trial of bilevel NIV in patients considered to require intubation and mechanical ventilation, unless the patient is immediately deteriorating. (Strong recommendation, moderate certainty of evidence) Rochwerg B, et al. Officical ERS/ATS clinical practice guidelines: noninvasive ventilation for acute respiratory failure. Eur Respir J 2017; 50:1602426
Somnolent. Confused but opens eyes and withdraws with painful stimulation GCS = 11
Bilevel NIV in COPD with Encephalopathy Limited data in patients with severe encephalopathy due to hypercapnic respiratory failure Prospective, non-controlled Spanish study included 66 patients with COPD exacerbation and coma (GCS 8) 86% avoided intubation and were eventually transferred to floor Look for single organ failure and improved mental status after 1 hour of NIV Diaz GG, et al. CHEST 2005; 127:952-60
How about bilevel NIV in Asthma?
Bilevel NIV in asthma exacerbation? Limited published data May improve RR, tidal volumes, expiratory flow Unclear if reduces intubation or improves mortality ERS/ATS Guideline: no recommendation Which patients most likely to benefit? No immediate need to intubate Slow to respond to initial therapy Low threshold to intubate? Good outcomes in patients intubated for asthma
Patients that do not stabilize or improve with NIV within 1 to 2 hours should (probably) be intubated.
Recipe for bilevel NIV success Apply early Be patient Gradual escalation of pressures and mask tightness Reassurance Be flexible/innovative Vary appliance based on patient response, needs Allow time Respiratory therapist needs sufficient time to do it right
Case Two 61 y.o. woman with kidney stones is admitted with septic shock due to pyelonephritis. On hospital day 2 she develops progressive dyspnea and hypoxemia. Her RR is 34/min and O2 sat 88% on 15 L/min O2 by nonrebreathing mask. She is alert, appropriate, using accessory muscles
Diagnosis?
Diagnosis: ARDS
A. Bilevel NIV Which of the following would you recommend for this patient? B. High-flow nasal cannula C. Proceed to endotracheal intubation D. Continue current therapy
Bilevel NIV in ARDS Higher pressures needed to decrease work of breathing Otherwise still have elevated O2 consumption by respiratory muscles Poor tolerance, air leaks, gastric insufflation Risk of larger tidal volumes Spontaneous efforts may induce lung injury Failure of NIV may be a risk factor for higher mortality Retrospective analysis of LUNG SAFE cohort found > 40% of pts receiving NIV with moderate or severe ARDS ended up intubated In propensity matched analysis, higher mortality (36% vs 25%) among NIVtreated patients with severe ARDS Bellani G et al. Am J Respir Crit Care 2017;195:67-77
Single center study found 18% of 83 ARDS patients using a helmet for NIV needed intubation compared to 61% receiving bilevel NIV by mask. Mortality was 22% lower in the helmet group. Patel BK, et al. JAMA 2016;315:2435-41
What is High-Flow Nasal Cannula Therapy? Specialized nasal cannula Flow rates 30 60 L/min typically used Heated and humidified oxygenated gas
Advantages of HFNC: Deliver High FIO2 Avoid entraining room air Inspiratory flow with quiet breathing 30 L/min, up to 100 L/min with distress Nasal cannula/simple mask deliver FIO2 1.0 at 15 L/min Venturi mask: flow as FIO2 FIO2 0.28 44 L/min FIO2 0.60 24 L/min HFNC delivers up to 60 L/min Adjust FIO2 with blender 0.21 1.0 Can deliver close to 100% O 2 even if inspiratory flow high
Other Potential Advantages of HFNC Helps with CO 2 elimination CO 2 washed out of upper airway decreases dead space Decreases work of breathing decreases CO 2 production Increases end-expiratory lung volume PEEP increased small amount Easier pulmonary toilet Gas heated and humidified Mouth uncovered Reduced aspiration risk? Well-tolerated compared to bilevel NIV Mauri T, et al. Intensive Care Med 2017; 43:2435 Mauri T, et al. Am J Respir Crit Care Med 2017; 195:1207
HFNC in Hypoxemic Failure: FLORALI Study 310 pts with non-hypercapnic acute hypoxemic failure randomized to HFNC, NIV, or O 2 via non-rebreather Additional details: 75% with bilateral infiltrates mostly pneumonia, presumably some ARDS NIV only median 8 hours/day. On HFNC when off NIV Results No significant difference in intubation overall Higher hazard ratio for death at 90 days in NIV and Standard groups vs HFNC Mortality benefit not reproduced in subsequent HOT-ER study Post-hoc analysis: in subset with PaO2:FIO2 < 200 mm Hg, lower intubation rate with HFNC (35%) vs NIV (58%) vs Standard O 2 (53%) Frat JP et al. New Engl J Med 2015;372:2185-96
Patients that do not stabilize or improve with HFNC within 1 to 2 hours should (probably) be intubated.
How about bilevel NIV in immunocompromised patients with acute hypoxemic respiratory failure? Small trials indicate bilevel NIV superior to standard O 2 therapy e.g. Antonelli M et al JAMA 2000; 283:235-41 Multicenter 2015 study found no difference in mortality or intubation among 374 patients randomized to bilevel NIV vs standard O 2 therapy. 85% were cancer patients Lemiale V et al. JAMA 2015; 314:1711-9 ERS/ATS guidelines recommend bilevel NIV in this population conditional recommendation with moderate certainty Post-hoc analysis of FLORALI study and other non-randomized studies suggest HFNC may be superior to bilevel NIV in this population Frat JP, et al. Lancet Respir Med 2016;4:646
NIV & HFNC in acute hypoxemic respiratory failure ERS/ATS Guidelines do not offer a recommendation on bilevel NIV given uncertainty of evidence Some trials of bilevel NIV and HFNC show benefit in patients with pneumonia FLORALI study: NIV, HFNC, standard O 2 therapy overall comparable results Likely that a subset of patients clearly benefit from NIV or HFNC but difficult to predict Considerations How many organ systems are failing? How quickly is this likely to improve? How much personnel support is available? Low threshold to proceed to intubation
Case 3 54 y.o. woman with ischemic cardiomyopathy and baseline EF 30% presents with increased dyspnea and lower extremity edema over the past 4 days. BP 100/70, HR 110, RR 32, O 2 sat 92% on 15 L/min O2 by nonrebreathing mask Alert, oriented, speaking in 1- word sentences Chest: bibasilar inspiratory crackles, using accessory muscles ABG: ph 7.32, PaCO 2 50, PaO 2 64 EKG: no acute ischemic changes First troponin: negative
Which of the following would you recommend for this patient? A. Continuous Positive Airway Pressure (CPAP) B. High-flow nasal cannula C. Proceed to endotracheal intubation D. Continue current therapy
Which of the following would you recommend for this patient? A. Continuous Positive Airway Pressure (CPAP) B. High-flow nasal cannula C. Proceed to endotracheal intubation D. Continue current therapy Do the results of the EKG and troponin matter?
Bilevel and CPAP in Acute Congestive Heart Failure Studies on the whole indicate CPAP or bilevel NIV reduce the need for intubation and reduce mortality Notable exception: Largest RCT with 1069 patients found no difference in intubation or mortality between CPAP, bilevel, and standard O 2 therapy. Patients not as sick? Allowed rescue use of noninvasive support Gray A, et al. New Engl J Med 2008;359:142-51. Patients with hypercapnia may be more likely to benefit Patients with acute coronary syndrome or cardiogenic shock excluded from studies and NIV not recommended in these groups
HFNC in Acute Congestive Heart Failure
Case 4 44 y.o. man intubated for severe ARDS following a motor vehicle collision. Day 9 passes weaning trial and extubated Over next 2 hours worsening O 2 sats and work of breathing BP 150/90, HR 116, RR 36, O 2 sat 91% on 15 L/min O2 by nonrebreather mask Alert, appropriate, anxious Chest: BS at bases. Using accessory muscles ABG: ph 7.36, PaCO 2 36, PaO 2 62
A. Bilevel NIV Which of the following would you recommend for this patient? B. High-flow nasal cannula C. Proceed to endotracheal intubation D. Continue current therapy
Bilevel NIV for Post-extubation Respiratory Failure Hypoxemic/Non-hypercapnic Studies show no benefit, others show possible harm 221 patients with mostly hypoxemic respiratory failure within 48 hrs of extubation randomized to bilevel NIV vs standard O 2 therapy found NIV delayed need for intubation but associated with higher ICU mortality (14 vs 25%). Subset of patients with COPD (10%) had lower rate of reintubation Esteban A, et al. New Engl J Med 2004;350:2452-60 Hypercapnic Bilevel reduces need for re-intubation in chronic lung disease Patients with worsening CO 2 post-extubation Prophylactic use applied immediately post-extubation
Bilevel NIV & HFNC for Prevention of Postextubation Respiratory Failure High-risk patients 604 patients randomized to HFNC or bilevel NIV for 24 hours immediately after extubated Risk: age > 65, intubated for CHF, moderate-severe COPD, BMI > 30, et al Proportion intubated for CHF or COPD: 32% for NIV vs 23% for HFNC No difference in rate of reintubation (about 20% each) Adverse effects requiring discontinuation of NIV 43% vs none with HFNC Hernandez G, et al. JAMA 2016;315:1354-61. Low-risk patients Same Spanish group found reintubation in 5% receiving HFNC vs 12% receiving standard oxygen therapy Hernandez G, et al. JAMA 2016;315:1354-61
Case 5 52 y.o. man is extubated in the PACU following gastric bypass surgery for morbid obesity When transferred to floor, experiencing pain with inspiration. BP 160/92, HR 102, RR 32, afeb, O 2 sat 90% on Venturi mask with FIO 2 60% Alert, appears uncomfortable Reduced chest wall excursion with BS bilaterally ABG: ph 7.36, PaCO 2 45, PaO 2 60
Should this patient be placed on bilevel NIV?
Bilevel NIV in Postoperative Failure Multiple trials show bilevel NIV reduces intubation rates in acute hypoxemic failure following abdominal surgery Multicenter RCT 293 pts within 1 week of surgery Reintubation 33% NIV vs 45% standard O 2 therapy Jaber S, et al. JAMA 2016; 315:1345 Bilevel beneficial in 1 RCT of lung resection patients Auriant I, et al. Am J Respir Crit Care 2001; 164:1231 CPAP for OSA routine in postoperative gastric bypass patients Limited information on bilevel but not considered a contraindication Limited experience with HFNC in postoperative patients Mostly comparing to O 2 therapy
HFNC in Post-operative Patients HFNC non-inferior to bilevel NIV in preventing or treating postoperative respiratory failure in 830 cardiothoracic surgery patients Treatment failure occurred in 21% of patients in each group Treatment failure defined by a composite of reintubation, switch to other treatment, or early discontinuation of therapy Stephan F et al. JAMA 2015; 313:2331
Summary COPD and CHF exacerbations Bilevel NIV is first line Post-operative hypoxemic failure More studies to support bilevel NIV than HFNC thus far Other causes of acute hypoxemic respiratory failure HFNC as good, and possibly superior to bilevel but use both with caution Post-extubation hypoxemic respiratory failure Bilevel NIV appears no better than standard O2 therapy, possibly worse Prophylactic HFNC noninferior to bilevel NIV and may be better tolerated Post-extubation hypercapnic respiratory failure Bilevel NIV is first line
Key References Rochwerg B, et al. Official ERS/ATS clinical practice guidelines: noninvasive ventilation for acute respiratory failure. Eur Respir J 2017; 50:1602426 Drake M. High-flow nasal cannula oxygen in adults: an evidencebased assessment. Ann Am Thorac Soc 2018; 15:145-155.