EBM Acute Pulmonary Oedema

Pedagogical disambiguation: Emergency Medicine Lecture Notes and Evidence Based emergency medicine principles from Professor A.F.T Brown and the Life in the Fast Lane team.

Diagnosis

• Acute heart failure syndrome (AHFS) spectrum can be divided into 5 groups as regards therapeutic management:
  • (i) Dyspnoea + /- congestion with elevated systolic blood pressure (SBP)>140 mmHg, usually with abrupt onset APO (most frequent type)
  • (ii) Dyspnoea + /- congestion with normal SBP 100-140 mmHg, usually with gradual onset predominant systemic oedema and milder APO
  • (iii) Dyspnoea + /- congestion with low SBP <100 mmHg, with predominant cardiogenic shock or end-stage cardiac failure (most fatal type)
  • (iv) Dyspnoea + /- congestion with signs of ACS such as chest pain
  • (v) Isolated RV failure usually without APO.

Mebazza A, Gheoghiade M, Pina I et al. Practical recommendations for pre- hospital and early in-hospital management of patients presenting with acute heart failure. Crit Care Med 2008;36:S129-39. [Reference]

• B-type natriuretic peptide (BNP) is elevated in left ventricular dysfunction and correlates with severity and prognosis. May help differentiate acute heart failure (AHF) from pulmonary disease, particularly in acutely dyspnoeic patients, although predictive cut-off levels and exact role are unclear.

Chircop R, Jelinek G. B-type natriuretic peptide in the diagnosis of heart failure in the emergency department. Emerg Med Australas 2006; 18:170-7. [Reference]

Maisel AS. Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. N Eng J Med 2002; 347:161-7. [Reference]

Treatment aims

• Decrease left ventricular diastolic pressure, by decreasing systemic vascular resistance and improving systolic and diastolic functional reserve.
• Promote coronary blood flow.
• Correct acute respiratory failure.
• In-hospital mortality for APO is up to 12%, with one-year mortality up to 40% !

Drugs

• Nitroglycerin S/L, topical or IV titrated to avoid hypotension.
  • Most rapidly venodilates, reduces LV afterload and corrects myocardial ischaemia. Ideal for AHFS type 1. (i) above.
  • Also consider in AHFS types 1. (ii) and (iv) if SBP > 110 mmHg.
  • Avoid in AHFS type 1. (iii) above.
  • Nitrates are used less often than frusemide + were used in just 27% of the patients admitted in the ADHERE registry (USA, 2003).

Wakai A, McMahon G. Nitrates for acute heart failure (Intervention protocol). Cochrane Database of Systematic Reviews 2005, Issue 1 [Reference]

• Frusemide IV.  Despite universal use, absolute efficacy is unclear. May cause decrease in cardiac output and increase PVR, plus increase PAOP in more chronic HF. Ideal for AHFS type 1. (ii) above.
• ACE inhibitor IV, orally or SC also reduces pre- and afterload, but little data in acute situation. Precipitous hypotension is hard to reverse, so use is best reserved for longer term management of HF.
• Morphine has relatively ineffective / unproven acute venodilating and sympatholytic effects, is rarely used (3% one study) and may result in respiratory depression in face of NIV and/or a poorer outcome. May have role in APO with diastolic dysfunction (ie. EF >40%) with elevated SBP.

Cleland J, Yassin A, Khadjooi K. Acute heart failure: focussing on acute cardiogenic  pulmonary oedema. Clinical Medicine 2010;10:59-64. [Reference]

Kumar R, Gandhi S, Little W. Acute heart failure with preserved systolic function. Crit Care Med 2008;36:S52-6. [Reference]

Cotter G, Metzkor E, Kaluski E et al.  Randomised trial of high-dose isosorbide dinitrate plus low-dose furosemide versus high-dose furosemide plus low-dose isosorbide dinitrate in severe pulmonary oedema.  Lancet 1998; 351:389-93. [Reference] (Commentary Gammage M: 382-3 [Reference])

Ventilatory assistance

• Non-invasive ventilation (NIV) refers to CPAP; or bilevel positive airway pressure (BiPAP) non-invasive pressure support ventilation (NIPSV), where IPAP – EPAP (≡PEEP) reflects the amount of pressure support delivered. (Note BiPAP^TM is also a Respironics^TM trademark name!)
• CPAP reduces mortality (RR 0.64) and need to intubate (RR 0.44), with no effect on incidence of new MI. BiPAP reduces need to intubate (RR 0.54), but not mortality or new MI. Thus CPAP preferred in APO due to AMI / ischaemia.
• Note 3CPO trial findings showed negative effect of NIV compared to standard medical therapy alone, but may be explained by sickest patients were excluded, low overall rates of intubation, ischaemia and mortality (i.e. their patients were different), and considerable treatment group crossover after first 2 hours.

Weng C, Zhao Y, Liu Q et al. Meta-analysis: noninvasive ventilation in acute cardiogenic pulmonary edema. Ann Intern Med 2010;152:590-600. [Reference]

Gray A, Goodacre S, Newby D et al. Noninvasive ventilation in acute cardiogenic pulmonary edema. The 3CPO trial. NEJM 2008;359:142-51. [Reference] and [Reference]

Vital F, Saconato H, Ladeira M et al. Non-invasive positive pressure ventilation (CPAP or bilevel NPPV) for cardiogenic pulmonary edema. Cochrane Database Syst Rev 2008;3. [Reference]

Ferrari G, Olliveri F, De Filippi G et al. Noninvasive positive airway pressure and risk of myocardial infarction in acute cardiogenic pulmonary edema: continuous positive airway pressure vs noninvasive positive pressure ventilation. Chest 2007;132:1804-9. [Reference]

Miscellaneous therapies

• Nesiritide, recombinant human BNP (rhBNP), longer acting vasodilator. Effective as nitrates, but hypotension more persistent, risk of renal impairment, some non-responders, and increased 30-day mortality (RR 1.86).

Wakai A, Seoighe B. Natriuretic peptides for acute heart failure (protocol). The Cochrane Library 2006, Issue 1. [Reference]

VMAC Investigators. Intravenous nesiritide vs nitroglycerin for treatment of decompensated congestive heart failure. JAMA 2002; 287:1531-40. [Reference]

• Newer drugs include levosimendan (calcium sensitiser), tezosentan (endothelin inhibitor) or pyruvate (alternate heart substrate). Little acute data.
• Traditional inotropic support is with dobutamine, dopamine, milrinone, enoximone or salbutamol for AHFS type 1. (iii) above, but may disastrously increase myocardial oxygen demand, especially in ACS with AHFS type 1. see (iv) above. Rarely need to add vasoconstrictor noradrenaline.
• Surgery +/- intra-aortic balloon counterpulsation (IABC) for free wall rupture, acute VSD or mitral incompetence from papillary rupture etc.

Task Force on Acute Heart Failure of the European Society of Cardiology. Executive summary of the guidelines on the diagnosis and treatment of acute heart failure. Eur Heart J 2005;26:384-416. (Excellent overall summary). [Reference]

Ware L, Matthew M. Acute pulmonary edema. NEJM 2005;353:2788-96. (Differentiating acute cardiogenic and noncardiogenic pulmonary edema). [Reference]