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Presented during the 1st Malaysian National Emergency Critical Care Symposium in Ipoh, Perak, Malaysia, Nov 2013.
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Updates on Asthma and COPD
Keng Sheng Chew School of Medical Sciences
Universi6 Sains Malaysia
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Conflict of Interest
• I declare I have received educa6onal grants from Astra-‐Zeneca (M) Sdn Bhd
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Outlines
• In asthma: • Con6nuous neb? • IV B2-‐agonist? • IV steroids? • An6cholinergics? • Magnesium sulphate?
• NIPPV? • When intubate? What to look for?
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Outlines
• In COPD: • Recent concepts • B2-‐agonists vs an6cholinergics? • NIPPV? • Issues of mechanical ven6la6on
• Hypoxic drive –how true is this fear?
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Updates on Asthma
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Pathophysiology of Asthma
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Pathological changes
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“Rules of 2” in asthma
• AXacks >2 6mes per week or • Needs rescuer inhaler >2 6mes per week
• Awakening due to nocturnal symptoms >2 6mes per month
• Use >2 canisters of relievers per year • If yes to any = uncontrolled, needs steroids
• (Adapted from GINA guideline)
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Con@nuous neb vs intermiCent neb?
• “Con6nuous” neb = con6nuous aerosol delivery or sufficient frequency of at least 1 neb q15 min or > 4 neb/hour
• In a Cochrane systema6c review, Camargo et al (2009), 8 trials, n = 461
• Con@nuous neb – Benefits in severe disease – Significant lung improvement at 2 – 3 hours – Similar side effects (tremors, increased K+, HR)
– Well tolerated 9
IV Beta-‐2 agonists vs inhaled Beta-‐2 agonists?
• Travers et al (2001), in a Cochrane systema6c review, 15 trials, n = 583
• IV beta agonists offer no therapeu6c advantage over inhaled forms of the drugs.
• However, no difference in autonomic side effects
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Early IV steroids use?
• Rowe et al (2009), Cochrane systema6c review, 12 trials, n = 863
• IV steroids given within 1 hour: • significantly reduced admission rates (OR = 0.40, 95% CI: 0.21 to 0.78)
• Benefits most pronounced among those with severe asthma and in those who have not yet been on systemic steroids prior to ED presenta6on
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An@cholinergics
• An6cholinergics – not to be used alone • Teoh et al (2012), in a Cochrane review, 4 trials, n = 171 – An6cholinergics alone less efficacious and more likely to fail
• An6cholinergics combined with SABA? – Griffiths et al (2013), in a systema6c review, 15 trials, n = 2497 (pediatrics), found
– combining an6cholinergic and SABA significantly reduces the risk for hospital admission
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Magnesium sulphate
• Blocks calcium channel • Relaxes bronchial smooth muscle • Inhibits contrac6le response to endogenous bronchoconstrictors
• Rowe et al (2009): • 7 trials, n = 665 • Overall no improvement in lung func6on, no improvement in adm rate
• BUT reduce admission rate in severe asthma subgroup
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NIPPV in Asthma?
• Lim et al (2012) in a Cochrane review, 5 trials, n = 206, preliminary results show NIPPV has benefit of – Reduced hospitaliza6on rate – Reduced 6me to discharge from ED – Improves lung func6on
• But s6ll lack of good evidence, remains controversial; NOT for rou6ne use
• Two of the studies: 2 intuba6ons needed in 45 par6cipants on NPPV vs no intuba6ons in 41 control pa6ents (risk ra6o 4.48; 95% CI 0.23 to 89.13)
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Mechanical ven@la@on
• 4 indica6ons for intuba6on (Brenner et al, 2009 in Proceedings of the ATS) – cardiac arrest – respiratory arrest or profound bradypnea – physical exhaus6on – AMS (agitated pa6ent, interfering with oxygen delivery)
• Hypercapnia per se without evidence of physical exhaus6on or mental changes IS NOT an indica6on
• Persistent hypercapnia despite treatment +/-‐ AMS is an indica6on (PaCO2 increase ~ 5mmHg/Hr or more than 55 – 70 mmHg)
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Mechanical ven@la@on
• Permissive hypercapnia -‐ minimize risk of increased intrathoracic pressure. Ini6al sepng: – TV 6 ml/kg – Rate 6/min – I:E up to 1:4
• Try keep Plateau pressure below 30 cm H20.
• Pplat (or lung distension pressure) gives an es6mate of average of end-‐insp alveolar P (Brenner et al, 2009)
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Induc@on Agents
• Ketamine • releases of catecholamines
• bronchial smooth muscle relaxa6on
• Side effects – hypersecre6on, hypertension, arrhythmias, and hallucina6ons
• rela6vely contraindicated in pa6ents with ischemic heart disease, hypertension, increased intracranial pressure. 17
Updates on COPD
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Reversible Irreversible
Source: Peter J. Barnes, MD
Basics
• COPD is a systemic disease, not just pulmomary (Agus6, 2005) – systemic inflamma6on, systemic oxida6ve stress, ac6va6on of circula6ng inflammatory cells, e.g. neutrophils, macrphages, and augmented levels of pro-‐inflammatory cytokines
• Extrapulmonary associa6ons: IHD, osteopenia, cachexia, malnutri6on, skeletal was6ng
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Bronchodilators
• Cochrane systema6c review by McCrory et al (2005) – No significant difference in changes in FEV1 between b2-‐agonists and the an6cholinergic ipratropium at 90 minutes and 24 hours and
– no advantage combining
• An6cholinergics – slower onset (15 min, peak 60 to 90 min, and longer 6 to 8 hrs).
• General consensus (GOLD) – SABA first, then an6cholinergics
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NIPPV in COPD
• Ram FSF et al (2004) in a Cochrane systema6c review, 14 trials involving n = 622 (outcomes of treatment failure), n = 541 (mortality)
• NIPPV resulted in • decreased mortality
• decreased need for intuba6on • reduc6on in treatment failure
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Mechanical ven@la@ons
• Issues with mechanical ven6la6on in COPD (BruloXe et al, 2012):
• poorer prognosis (mortality rates between 20% and 73%)
• a mean life expectancy of 1 year
• Barotrauma, infec6ons
• Discuss with family regarding pros and cons
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Hypoxic Drive in COPD?
• How real is this fear? • Started off with a paper by E.J.M Campbell in 1960
• Really no science behind it! Consensus opinion
• A Cochrane review by Aus6n Wood-‐Baker (2009) – “No relevant trials have been published to date, so there is no evidence to indicate whether different oxygen therapies in the pre-‐hospital se@ng have an effect on outcome for people with acute exacerbaBons of COPD”
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Hypoxic Drive in COPD?
• Plant et al (2000) shows an associa6on between increased oxygen with hypercapnea, respiratory acidosis, and ICU admission but this does not occur in every pa6ent given increased FiO2.
• May happen
• Careful observa6on of this pa6ent • BUT remember: the risks of withholding oxygen are much greater than giving them too much!
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Summary
• In asthma: • Con6nuous neb? • IV B2-‐agonist? • IV steroids? • An6cholinergics? • Magnesium sulphate?
• NIPPV? • When intubate? What to look for?
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Summary
• In COPD: • Recent concepts • B2-‐agonists vs an6cholinergics? • NIPPV? • Issues of mechanical ven6la6on
• Hypoxic drive -‐ controversials
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References • Camargo Jr CA, Spooner C, Rowe BH. Con6nuous
versus intermiXent beta-‐agonists for acute asthma. Cochrane Database of Systema6c Reviews 2003, Issue 4. Art. No.: CD001115. DOI: 10.1002/14651858.CD001115
• Travers A, Jones AP, Kelly K, Barker SJ, Camargo CA, Rowe BH. Intravenous beta2-‐agonists for acute asthma in the emergency department. Cochrane Database Syst Rev.2001;(2) :CD002988
• Rowe BH, Spooner C,Ducharme F, Bretzlaff J, BotaG. Early emergency department treatment of acute asthma with systemic cor6costeroids. Cochrane Database of Systema6c Reviews 2001, Issue 1. Art. No.: CD002178. DOI: 10.1002/14651858.CD002178.
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References
• Griffiths B, Ducharme FM. Combined inhaled an6cholinergics and short-‐ac6ng beta2-‐agonists for ini6al treatment of acute asthma in children. Cochrane Database of Systema6c Reviews 2013, Issue 8. Art. No.: CD000060. DOI: 10.1002/14651858.CD000060.pub2.
• Lim WJ, Mohammed Akram R, Carson KV, Mysore S, Labiszewski NA, Wedzicha JA, Rowe BH, Smith BJ. Non-‐invasive posi6ve pressure ven6la6on for treatment of respiratory failure due to severe acute exacerba6ons of asthma. Cochrane Database of Systema6c Reviews 2012, Issue 12. Art. No.: CD004360. DOI 10.1002/14651858.CD004360.pub4. 29
References
• Barry Brenner, Thomas Corbridge, and Antoine Kazzi "Intuba6on and Mechanical Ven6la6on of the Asthma6c Pa6ent in Respiratory Failure", Proceedings of the American Thoracic Society, Vol. 6, No. 4 (2009), pp. 371-‐379.
• McCrory DC, Brown CD. An6cholinergic bronchodilators versus beta2-‐sympathomime6c agents for acute exacerba6ons of chronic obstruc6ve pulmonary disease. Cochrane Database of Systema6c Reviews 2003, Issue 1. Art. No.: CD003900. DOI:10.1002/14651858.CD003900.
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References
• Agus6 AG. Systemic effects of chronic obstruc6ve pulmonary disease. Proc Am Thorac Soc 2005; 2 (4):367-‐70; discussion 71-‐2.
• Ram FSF, Picot J, Lightowler J, Wedzicha JA. Non-‐invasive posi6ve pressure ven6la6on for treatment of respiratory failure due to exacerba6ons of chronic obstruc6ve pulmonary disease. Cochrane Database of Systema6c Reviews 2004, Issue 3. Art. No.: CD004104. DOI: 10.1002/14651858.CD004104.pub3.
• BruloXe CA, Lang ES. Acute exacerba6ons of chronic obstruc6ve pulmonary disease in the emergency department. Emerg Med Clin North Am. 2012; May;30(2):223-‐47, vii.
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References
• Teoh L, Cates CJ, et al. An6cholinergic therapy for acute asthma in children. Cochrane Database Syst Rev 2012, Issue 4: CD003797.
• Plant PK, Owen JL, Elliot MW. One year period prevalence study of respiratory acidosis in acute exacerba6ons of COPD: implica6ons for the provision of noninvasive ven6la6on and oxygen administra6on. Thorax 2000;55:550–4.
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