NIV in Acute Respiratory Failure: Where we fail? Dr Shrikanth Srinivasan MD,DNB,FNB,EDIC Consultant, Critical Care Medicine Medanta, The Medicity
Use of NIV 1998-2010 50 45 40 35 30 25 20 15 10 5 0 1998 2004 2010 COPD CHF ARF
Response to NIV Antonelli ICM 2001, 27:1718-1728
Avoid NIV failure by selecting patients likely to succeed Diagnosis Green Light COPD, CHF, CPE (hypercapnic respiratory failure) Yellow light Asthma, Obesity hypoventilation, upper airway obstruction, post op, post-extubation,trauma, ARDS (mild), some pneumonias Red Light Pneumonia/ARDS-MODS, Pulm Fibrosis, Tight upper airway obstruction
Case 1 63 y/f in ED with increasing SOB. Severe COPD on LTOT Baseline FEV1 0.53L and PaCO2 48 mm Hg. Cough with yellowish phlegm, but raises it without difficulty. On exam: mod resp distress, + accessory muscle RR 28 BP 144/82, cooperative, has teeth, 69 kg lungs reveal bilat rhonchi, expiratory phase ABG 7.28/PaCO2 56/PaO2 64 on 4 L/min O2, CXR: hyperinflated but no infiltrates
Likelihood of NIV Success? High? Low?
NIV: Determinants of Success and Failure 12 COPD pts treated with Nasal Ventilation Success FailureSuccess APACHE II 15 21 Teeth yes No Pneumonia No 43% Excess secretions No Yes Mouth leaks (ml) 100 314 Poor coordination No Yes After 1 hour Yes No PaCO2 >10, RR, ph > 0.5 Yes No Soo Hoo et al, CCM 1994
CASE 2 hr of NIV Agitated and unable to tolerate IPAP pressure over 10 cm H2O IPAP, 5 cm H2O EPAP, 40% FIO2). Asynchronous with vent. Dyspnea worse than at 1hr, mask leaks. RR 28, still access muscle use, BP, pulse steady. ABG 7.25/ PaCO2 62, PaO2 70. Is this patient failing now? What would you do?
PREDICTORS OF NONINVASIVE VENTILATION SUCCESS OR FAILURE Predictors of NIV failure observed in COPD patients with ARF (1) Lower arterial ph at baseline (2) Greater severity of illness, as indicated by Acute Physiology and Chronic Health Evaluation (APACHE) II score (3) Inability to coordinate with the ventilator (4) Inability to minimize the amount of mouth leak with nasal mask ventilation Current Opinion in Critical Care: February 2013 - Volume 19 - Issue 1 -p 1 8
PREDICTORS OF NONINVASIVE VENTILATION SUCCESS OR FAILURE Predictors of NIV failure observed in COPD patients with ARF (5) Less efficient or less rapid correction of hypercapnia, ph, or tachypnea in the early hours (6) Functional limitations caused by COPD before ICU admission, evaluated using a score correlated to home activities of daily living (ADL) (7) Higher number of medical complications (particularly hyperglycemia) on ICU admission Current Opinion in Critical Care: February 2013 - Volume 19 - Issue 1 -p 1 8
Strategies to Avoid NIV Failure Proper location, monitoring, experienced staff ICU or stepdown for new starts unless very stable Monitor continuously for: subjective responses comfort, dyspnea, anxiety, agitation vital signs (RR), (accessory muscle use) synchrony, leaks secretions gas exchange; oximetry, Blood gases complications
Strategies to Avoid NIV Failure Assure Adequate Gas Exchange Comfortable mask Oronasal Adequate Ventilator Settings Correct leaks Ventilator designed for NIV Optimal ventilator settings IPAP adjusted upward to treat resp distress, decrease WOB EPAP increased to counterbalance auto-peep, improve oxygenation Increase IPAP and EPAP in parallel (sufficient Δ) FIO2 to keep O2sat > 90%
Case 2 75 year old male k/c/o CAD Acute onset dyspnea B/L coarse crepts+ BP:180/100 mm Hg Cardiogenic Pulmonary Edema
Questions Are CPAP and NIV similar? Is there an improvement in outcome? Am I increasing the risk of cardiac arrest?
Key Messages The evidence of NIV/CPAP over standard medical therapy is robust Its use as a FIRST LINE INTERVENTION in cardiogenic pulmonary edema is becoming mandatory CPAP and NIV have similar efficacy in decreasing the need for ETI and mortality WITHOUT increasing risk of AMI NIV can be considered to be preffered therapy in acute cardiogenic pulmonary edema with hypercapnia Nieminen MS, Bohm M: Executive summary of the guidelines on the diagnosis and treatment of acute heart failure: the task force on Acute heart failure of European Society of cardiology. Eur Heart J 2005. 26:384-416
NIV messages When: Start early Where: In ER Who: Experienced staff Outcome: Usually rapid resolution and transfer to ward
Case 3 60 year old male, diabetic, SAPS II 37 P/F ratio 120 RR 37 bpm B/L pulmonary infiltrates Dyspnea No s/o LV failure ARDS
Questions?
n = 51 n = 54 Ferrer et al. AJRCCM 2003; 168: 1438
CCM 2007
Rana, Critical Care 2006
Summary Objective: To assess rates and predictive factors of non-invasive ventilation (NIV) failure in patients admitted to the intensive care unit (ICU) for non-hypercapnic acute hypoxemic respiratory failure (AHRF) Methods: observational cohort study
Summary Results: Among 113 patients receiving NIV for AHRF, 82 had ARDS and 31non-ARDS. Intubation rates significantly differed between ARDS and non- ARDS patients (61% versus 35%,P = 0.015) and according to clinical severity of ARDS: 31% in mild, 62% in moderate, and 84% in severe ARDS (P = 0.0016). In-ICU mortality rates were 13% in non-ards, and, respectively, 19%, 32% and 32% in mild, moderate and severe ARDS (P = 0.22). Among patients with moderate ARDS, NIV failure was lower among those having a PaO2/FiO2 >150 mmhg (45% vs. 74%, p = 0.04).
Figure 2 Rates of NIV failure and in-icu mortality (expressed in %) according to clinical criteria for acute respiratory distress syndrome (ARDS) and clinical severity of ARDS using the Berlin definition. Intubation rate was significantly different between the four groups (P = 0.001) but not the mortality rate (P = 0.22). Intubation and mortality rates were higher in patients with moderate or severe ARDS than in patients with mild or without clinical criteria for ARDS
Figure 3 Kaplan-Meier estimate of survival without intubation according to presence of ARDS and its severity at presentation, stratified as no ARDS or mild ARDS (solid line) or moderate or severe ARDS (dashed line). The difference between the two groups was highly significant (P <0.0001, log-rank test). (ARDS, acute respiratory distress syndrome).
Summary NIV failure was associated with active cancer, shock, moderate/severe ARDS, lower GCS and lower PEEP level at NIV initiation. Among intubated patients, ICU mortality rate was 46% overall and did not differ according to the time to intubation. Conclusions: NIV can be first-line approach in non-ards and mild ARDS NIV may be attempted in ARDS patients with a PaO2/FiO2 > 150. 84% of severe ARDS required intubation and NIV did not appear beneficial in this subset of patients. However, the time to intubation had no influence on mortality.
Predictors of NIV failure observed in hypoxemic patients with ARF (1) Higher severity score [Simplified Acute Physiology Score (SAPS) II35 / SAPS II>34/higher SAPS II (2) Older age (>40 years) (3) Presence of acute respiratory distress syndrome or community-acquired pneumonia (4) Failure to improve oxygenation after 1 h of treatment (PaO2:FiO2 146 /PaO2:FiO2 175)
Predictors of NIV failure observed in hypoxemic patients with ARF (5) higher respiratory rate under NIV (6) need for vasopressors (7) need for renal replacement therapy
NIV in Immunocompromised patients
Risk factor for failure At Multivariate analysis two major risks factors for NIMV failure in immunocompromised: SAPS II score (OR=2.012, 95% CI: 1.006 4.026; P=0.04 ALI/ARDS (OR= 2.266, 95%CI: 1.346 3.816; P=0.002).
NIV in Asthma
NIV in acute asthma Potential Goals of NIV in asthma
Summary Lack of strong supporting evidence In the absence of conclusive data, a short trial of NPPV (eg, one to two hours) maybe used: As an alternative to intubation in patients who have failed a trial of standard medical treatment To prevent intubation in patients with mild-to-moderate acute respiratory failure who do not need immediate ventilatory support To prevent acute respiratory failure in patients who do not have substantial impairment of gas exchange To accelerate bronchodilation in patients who do not need mechanical ventilation
Role of NIV post extubation?
Postextubation ARF Reintubation 48% Reintubation 72%
Prevention of postextubation ARF Reintubation 11% Reintubation 8%
NIV IN THE POSTEXTUBATION PERIOD Prophylactic NIV after extubation may be useful to prevent acute respiratory failure in selected populations NIV employed for treating postextubation acute respiratory failure has no proven benefit and can even increase mortality by delaying reintubation
NONINVASIVE VENTILATION(NIV) IN THE POSTEXTUBATION PERIOD NIV was found to be effective in preventing postextubation respiratory failure in patients having hypercapnia at the end of the SBT. NIV could reduce the risk of reintubation in postoperative patients after major elective abdominal surgery or lung resection, and could even reduce mortality in this latter group
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