Life in the Fast Lane

1. It takes your food seven seconds to get from your mouth to your stomach.
2. One human hair can support 3 kg (6 lb).
3. The average man’s penis is three times the length of his thumb.
4. Human thighbones are stronger than concrete.
5. A woman’s heart beats faster than a man’s.
6. There are about one trillion bacteria on each of your feet.
7. Women blink twice as often as men.
8. The average person’s skin weighs twice as much as the brain.
9. Your body uses 300 muscles to balance itself when you are standing still.
10. If saliva cannot dissolve something, you cannot taste it.

Women reading this will be finished now.

Men who read this are probably still busy checking their thumbs

Tags: body, health, humor, humour, statistics

AFTB lecture notes - Acute Pulmonary Oedema (APO)

DIAGNOSIS

Acute heart failure syndrome (AHFS) spectrum can be divided for therapeutic management into:

• Dyspnoea + /- congestion with elevated systolic blood pressure (SBP) >140 mmHg, usually with abrupt onset APO (most frequent type)
• 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)
• Dyspnoea + /- congestion with signs of ACS such as chest pain
• 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.

B-type natriuretic peptide (BNP)

• 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.

MEDICATIONS - Options

• 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. a) i) above. Consider in AHFS types 1. a) ii) and iv) if SBP > 110 mmHg. Avoid in AHFS type 1. a) iii) above.
• 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. a) 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 best  established in longer term management of HF.
• Morphine has relatively ineffective venodilating and sympatholytic effects, and may result in poorer outcome, or respiratory depression in face of NIV. May have role in APO with diastolic dysfunction (ie. EF >40%) with elevated SBP.

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

Kosowsky J, Kobayashi L. Acutely decompensated heart failure: Diagnostic and therapeutic strategies for the new millenium. Emergency Medicine Practice: An Evidence-based Approach to Emergency Medicine 2002; 4(2):1-28

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]

Ventilatory assistance

• Non-invasive ventilation (NIV) with CPAP or bilevel non-invasive pressure support ventilation (NIPSV - note BiPAP is a tradename) reduces mortality by 40%, particularly with CPAP, and both reduce need to intubate.

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]

Peter JV et al. Effect of non-invasive positive pressure ventilation (NIPPV) on mortality in patients with acute cardiogenic pulmonary oedema: a meta-analysis. Lancet 2006;367:1155-63. [Reference]

Masip J et al. Noninvasive ventilation in acute cardiogenic pulmonary oedema: systematic review and meta-analysis. JAMA 2005;294:124-30. [Reference]

• Excess mortality not confirmed on meta-analysis, thought related to AMI onset with NIPPV, compared with using CPAP at 5-7.5 cm H2O for APO.

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 brain natriuretic peptide BNP) longer acting vasodilator as effective as nitrates, but hypotension more persistent.

VMAC Investigators. Intravenous nesiritide vs nitroglycerin for treatment of decompensated congestive heart failure. JAMA 2002; 287:1531-40. [Reference] (Editorial: Poole-Wilson P. Treatment of acute heart failure. Out with the old, in with the new. JAMA 2002; 287:1578-1580) [Reference]

• New drugs include levosimendan (calcium sensitiser), tezosentan (endothelin inhibitor) and pyruvate (alternate heart substrate).
• Traditional inotropic support is with dobutamine, dopamine, milrinone, enoximone or salbutamol for AHFS type 1. a) iii) above, but may disastrously increase myocardial oxygen demand, especially in ACS with AHFS type 1. a) iv). 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. [Reference] (Excellent overall summary).

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

Tags: AFTB, aftb lecture notes, APO, pulmonary edema

Thanks to Scalpels Edge who has just given me the Kreativ Blogger Award! Each winner of the award gets to list six things he or she is happy about.

1. Kids - when everything around you falls apart, they stand by you - resolute to the end
2. Literature - collated ramblings assist to disambiguate
3. The end of Movember - a great deal has been raised for charity, but with the arrival of December I will now be able to pick my kids up from school without a police escort
4. Nippers - junior life saving at Floreat Surf Life Club. Amazing and exhilarating experience.
5. Australia - Love, loss and landscape
6. Leonard Cohen - World tour arriving in Perth February 2009 - a paragon of idealistic cognition through eclectic musings 

In addition, it is with fervent honor that I acknowledge and present the medical machinations and musings of the following MedBlogs for your consumption

• My Emergency Medicine Blog - Questions and Answers on the fly from an Emergency Physician
• Clinical Cases - Great presentation, documentation and reference database of clinical scenarios in medicine
• Aequanimitas - Erudite Aussie medical commentary
• OzeMedicine - Political medical commentary for Australia with rapidly developing reference wiki
• Your ER Doc - Emergency Medicine from the ‘cutest doc’ on the block…
• The Beauty of Orthopaedics - Presented by Andreas Richards from Munich

 

One by one the guests arrive

The guests are coming through

The open-hearted many

The broken-hearted few

 

And those who dance begin to dance

And those who weep begin

Welcome, welcome, cries a voice

Let all my guests come in

Tags: award, kreativ blogger

AFTB lecture notes - Aortic Dissection

EPIDEMIOLOGY

• Incidence: 3 cases per 100 000 people per year; up to 25% missed diagnosis ante-mortem.  ‘Typical’ case 60-80 years old M>F. Overall in-hospital mortality 27%.
• Risk factors:
  • Inherited disease (especially younger patients < 40 yrs) - Marfan’s syndrome (fibrillin gene mutations), Ehlers-Danlos syndrome type IV (collagen defects), Turner syndrome, annulo- aortic ectasia and familial aortic dissection.
  • Aortic wall stress: Hypertension (72%), previous cardiovascular surgery, bicuspid or unicommisural aortic valve, aortic coarctation, iatrogenic, infection (syphilis), arteritis such as Takayasu’s or giant cell, aortic dilatation / aneurysm, wall thinning, ‘crack’ cocaine (abrupt catecholamine-induced hypertension).
  • Reduced resistance aortic wall: Increasing age, pregnancy (debatable).

Golledge J, Eagle K. Acute aortic dissection. Lancet 2008;372:55-66. [Reference]

European Society of Cardiology. Diagnosis and management of aortic dissection. Eur Heat J 2001;22:1642-81. [Reference PDF]

CLINICAL PRESENTATION (with incidence %)

• Severe or ‘worst ever’ (90%), abrupt (90%), sharp (64%) or tearing (50%) retrosternal or interscapular pain, migrating (16%), down the back (46%), maximal at onset (not crescendo build up, as in an AMI).
• Complications:
  • Aortic incompetence (32%), cardiac tamponade, myocardial ischaemia (although only 2-5% of ECG’s mimick AMI). Different BP >20 mmHg in arms, or missing pulse (15%).
  • Pleural rub or effusion, haemothorax.
  • Altered consciousness, syncope (13 %), hemiplegia (5%), paraplegia.
  • Abdominal pain (43% descending, 22% ascending), intestinal ischaemia, bowel infarct.
  • Oliguria, haematuria.

DIAGNOSIS

• CXR - Widened mediastinum (56-63%), abnormal aortic contour (48%), aortic knuckle double calcium sign >5mm (14%), pleural effusion (L>R), tracheal shift, left apical cap. ‘Normal’ in 11-16%.
• Echocardiography - Transthoracic 75% diagnostic Type A (ascending), 40% descending (Type B). Transoesophageal (TOE).  Much higher sensitivity / specificity, though operator-dependent, need sedation, and is less available. Useful in ICU / perioperative.
• Helical CT - Useful screen for widened mediastinum. Newer multiplane/slice scanners may now negate additional need for TOE or aortography to plan operative management.
• Aortography - Was the traditional gold standard, delineating aortic incompetence and associated branch vessel involvement as well. 
• MRI / MRA - Excellent sensitivity and specificity limited by availability.

Hayter R, Rhea J, Small A et al. Suspected aortic dissection and other aortic disorders: multi-detector row CT in 373 cases in the emergency setting. Radiology 2006;238:841-52. [Reference]

MANAGEMENT

• Ascending Type A - Immediate blood pressure control prior to transfer for operation using IV beta blocker (propranolol, esmolol or labetalol) combined with SNP (or GTN) as vasodilators aiming for SBP 100-120 mmHg, and surgery or endovascular stenting.
• Descending Type B - Medical control of BP with beta blockers, with surgery or endovascular stent grafting for selected patients with an unfavourable outlook.

Reed K, Curtis L. Aortic Emergencies: Part 1 - thoracic dissections and aneurysms. Emergency Medicine Practice 2006;8(2):1-24. EB Medicine

Eggebrecht H et al. Endovascular stent-graft placement in aortic dissection: a meta-analysis. Eur Heart J 2006;27:489-98. [Reference]

Nienaber C et al. Aortic dissection: new frontiers in diagnosis and management: Part 1: from etiology to diagnostic strategies. Circulation 2003;108:628-35. [Reference]

Hagan PG, Nienaber CA, Isselbacher EM et al.  The International Registry of Acute Aortic Dissection (IRAD).  JAMA 2000; 283:897-903. [Reference]

Tags: AFTB, aftb lecture notes, cardiology, cardiothoracic, dissection, lecture notes

With the era of open source, micro-blogging, stumbling and tweeting now upon us - I, as an altruistic educator, researcher and medical professional bathe in the warm surge of ‘idealistic’ sharing’ that washes over me…but I have questions…so many questions…

What is the future/role of major publishing companies in light of open access; self-publishing and copyright free electronic information? When we write articles, perform research, write lectures and devise eLearning programmes - how much of this material ‘belongs’ to the author? What constitutes copyright for the educating physician?

There is ‘evolution’ and ‘revolution’ afoot.

Read the full article on ‘Evolution and Revolution in Medical Publishing‘ at the 28 hour Day Diet.

Tags: copyright, medical literature, medical publishing, publishing