Sub-category: Intensive Care for Respiratory Distress

Transcription

1 Course n : Course 3 Title: RESPIRATORY PHYSIOLOGY, PHYSICS AND PATHOLOGY IN RELATION TO ANAESTHESIA AND INTENSIVE CARE Sub-category: Intensive Care for Respiratory Distress Topic: Acute Respiratory Distress Syndrome (ARDS) Date: May 6-8, 2016 Language: City: Country: Speaker: English Lahore Pakistan Prof. M. Qamarul Hoda

2 Disclosure I do not have any relevant financial or other interests, arrangements or affiliations that would constitute a conflict of interest

3 A 23-year male is admitted after a motor vehicle crash in which he sustained chest and abdominal injuries including multiple left-sided rib fractures and a ruptured spleen. He required an emergency splenectomy, and was transfused 10 units of blood prior to his admission to the intensive care unit, where he remains intubated and ventilated. Five hours after admission to ICU, his blood pressure and pulse are stable, but his arterial oxygen saturation has fallen from 96% to 85% despite 100% inspired oxygen.

4 Acute Respiratory Distress Syndrome (ARDS) Dr. Muhammad Qamarul Hoda

5 Definition Features AECC 1994 BERLIN 2012 Onset Chest imaging Pulmonary edema Classification (severity) Acute (not defined) No risk factor formally defined Bilateral opacities on chest radiograph PAOP 18 mmhg when measured or no clinical evidence of raised left atrial pressure ALI = PaO 2 /FiO ARDS = PaO 2 /FiO Within 7 days of a known risk factor Bilateral opacities consistent with pulmonary edema either on chest X-ray or CT chest Non-hydrostatic edema; not fully explained by heart failure or fluid overload Echocardiography or another objective measure may be required Mild 200<PaO 2 /FiO Moderate 100<PaO 2 /FiO Severe <PaO 2 /FiO The ARDS definition Task Force. JAMA. 2012;307(23):

6 BERLIN DEFINITION (2012) Severity PaO 2 /FiO 2 (mmhg) Ventilatory assistance (CPAP/PEEP) Without CPAP/PEEP With 5cmH 2 O CPAP/PEEP Mild < Moderate < Severe The ARDS definition Task Force. JAMA. 2012;307(23):

7 BERLIN DEFINITION Compared with the AECC definition, the Berlin Definition had better predictive validity for mortality, with an area under the ROC of (95% CI ) vs (95% CI ; P<.001) Gordon D. Rubenfeld, MD,JAMA. 2012;307(23):doi: /jama

8 Clinical Risk Factors for ARDS How many risk factors in our patient?

9 PATHOGENESIS 1. Exudative phase Day 1 to day 7 2. Proliferative phase Day 7 onwards 3. ± Fibrotic phase

10 Pressure volume curve - Healthy lungs vs ARDS (Monaldi Archives for Chest Diseases-Pulmonary Series 2003;59(2): with permission)

11 Pressure volume curve (UIP) (LIP or P flex )

12 Management of patients with ARDS Search & treat the underlying cause Supportive: A. Ventilatory management B. Rescue therapies C. Non-ventilatory management

13 A. Mechanical Ventilation in ARDS Non Invasive Ventilation Lung Protective ventilation Low TV ventilation P Plat 30cmH 2 O PEEP Low vs High PEEP Ventilation in prone position HFOV and ECMO

14 A. Conventional Mechanical ventilation Concerns

15 VILI/VALI? The lung injury associated with inappropriate mechanical ventilation in patient with ARDS. Causes Volutrauma Barotrauma Atelectrauma Biotrauma

16 Heart Heart Spontaneous breathing Conventional MV Heart Heart LUNG areas in ARDS (supine) during end inspiration and end expiration Normally aerated Poorly aerated Non-aerated Consolidated Claude Gue ŕin Eur Respir Rev 2014; 23:

17 What is the most appropriate ventilation strategy to avoid VILI/VALI? Lung Protective Ventilation

18 Low Tidal Volume Ventilation Evidenced based review

19 Meta-analysis favoring low TV ventilation Five RCTs ( Amato, Stewart, Brochard, Brower, and ARMA) 1202 patients low TV ventilation significantly improved 28 day mortality compared to conventional ventilation Petrucci N, Iacovelli W. Cochrane Database Syst Rev 2004;CD003844

20 Open Lung Ventilation Evidenced based review

21 Pressure volume curve Open Lung (UIP) (LIP or P flex )

22 Effect of PEEP and Recruitment Strategy Without PEEP With PEEP ARDS Increase in the aerated lung areas after maximal recruitment strategy and PEEP. Curr Opin Crit Care 2014,20:10-16

23 PEEP ALVEOLI - NEJM 2004;351: EXPRESS - JAMA 2008;299: LOVS - JAMA 2008;299: Meta-analysis of above THREE trials (High vs Low PEEP) revealed no difference in hospital mortality. However, higher PEEP was associated with reduced ICU mortality (in subgroup of patients with PaO 2 /FiO 2 ratio 200mmHg), total rescue therapies, and death after rescue therapy. Briel M, et al. JAMA 2010;303(9):

24 B. Rescue therapies during MV Recruitment maneuvers High levels of PEEP CPAP 30-35cmH 2 O applied for 30s Prone positioning HFOV and ECMO Nitric oxide (NO)

25 Prone ventilation Early RCTs and Meta-analyses initially reported no mortality benefit with prone ventilation in ARDS. Gattinoni L et al.nejm 2001;345: Guerin C et al. JAMA 2004;292: Mancebo J et al. Am J Respir Crit Care Med 2006;173: Taccone P et al. (PS II study) JAMA 2009;302:

26 Prone ventilation Recently, PROSEVA and a meta-analysis of seven RCTs have reported mortality benefits from prone ventilation in the subpopulation of patients with severe ARDS (PaO 2 :FiO 2 <100mmHg) Sud S et al. Systematic review and meta-analysis. Intensive Care Med 2010;36:585 Guerin C et al. PROSEVA study. NEJM 2013;368:

27 Prone ventilation Subsequent meta-analyses have confirmed these findings but ONLY in those received low tidal volume ventilation. Beitler JR et al. Meta-analysis. Intensive Care Med 2014;40: Hu SL et al. Meta-analysis. Crit Care 2014;18:R109

28 Prone positioning PROSEVA (Prone positioning in Severe ARDS) Multicenter, prospective, RCT Conclusions: EARLY (12-24hours) application of PROLONGED ( 16hours) prone positioning in patients with SEVERE ARDS (PaO 2 /FiO 2 <150mmHg, FiO 2 0.6, PEEP 5cmH 2 O) significantly (P<0.001) decreased 28-day (16.0% vs 32.8%) and 90 day Mortality. Geurin Claude et al. PROSEVA Clinical trials. NEJM 2013;368:

29 Rescue therapies Prone positioning Improved oxygenation and reduced VALI/VILI by: a) Alveolar recruitment - Guerin C et al. Intensive Care Med 1999;25: b) Improved V/Q matching by redistribution Richard JC et al. J Apply Physiol 2002;93: c) Elimination of lungs compression by the heart Albert RK. Am J Respir Crit Care Med 2000;161: d) Lower incidence of VILI by reducing parenchymal lung stress and strain Mentzelopoulos SD. Eur Respir J 2005;25:

30 Rescue therapies Inhaled Nitric Oxide (ino) Did not reduce mortality or duration of MV. The improvements in oxygenation were small and unsustained May be useful as a rescue therapy in patients with refractory hypoxemia. Sangeeta Mehta et al. Critical Care Medicine 2003;31(2): Griffiths MJ. NEJM 2005;353:

31 HFOV and ECMO Rescue therapies HFOV: promising prospects. A recent meta-analysis on HFOV - decreased mortality rates, but with substantial heterogeneity among trials. Sud S et al: systematic review and meta-analysis. BMJ. 2010; 340:c2327. ECMO: A recent trial and a meta-analysis found a reduction in mortality and severe disability rates at six months. There is insufficient evidence to provide a recommendation clinicians should consider it in the context of other rescue therapies. Mitchell MD et al. A systematic review.crit Care Med. 2010; 38:

32 Dose, Timing, and Duration are important Short course, high dose (30mg/kg/d for 24 hrs) No survival benefit, harmful Bernard GR et al. NEJM 1987;317: Luce JM et al. Am Rev Respir Dis 1988;138:62-68 Early & Prolonged, low dose (1 mg/kg/d for 28 days) Improved short & long term survival Favorable benefit/risk profile Pharmcotherapy Methylprednisolone and ARDS Meduri GU et al. Chest 2007;131:

33 CONSENSUS ON STEROIDS ACCCM Recent consensus statement Early severe ARDS - 1 mg/kg/d of methylprednisolone as infusion and tapered over 4 weeks With un-resolving ARDS, beneficial effects were shown for (2 mg/kg/d) initiated before day 14 of ARDS and continued for at least 2 weeks after extubation If treatment is initiated after day 14, no evidence has shown either benefit or harm Marik PE, et al. Consensus statements from ACCCM. Crit Care Med 2008;36:

34 Fluid and Haemodynamic Management Conservative vs liberal approach: Improved oxygenation & LIS Increased ventilator & ICU free days Wiedemann H P et al. FACTT. NEJM 2006;354: Combination therapy with albumin & furosemide may improved fluid balance, oxygenation, and hemodynamics. Martin GS et al. Crit Care Med 2002;30: Crit Care Med 2005;33:

35 Summary Fully supported mode of MV Low TV ventilation (6ml/kg) Target lowest plateau pressure ( 30cmH 2 O) Prone positioning, now consider as an effective treatment modality in severe cases of ARDS Open lung ventilation with high PEEP and other recruitment maneuvers should be reserved for refractory cases.