Page 677 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

496 PART 4: Pulmonary Disorders

KEY REFERENCES CHAPTER Status Asthmaticus
• Austin MA, Wills KE, Blizzard L, et al. Effect of high flow oxy- 55 Thomas Corbridge
gen on mortality in chronic obstructive pulmonary disease Jesse B. Hall
patients in prehospital setting: randomised controlled trial. BMJ.
2010;341:c5462.
• Barreiro E, de la Puente B, Minguella J, et al. Oxidative stress
and respiratory muscle dysfunction in severe chronic obstruc- KEY POINTS
tive pulmonary disease. Am J Respir Crit Care Med. 2005;171: • While some data suggest a decrease in the number of asthmat-
1116-1124.
ics requiring intubation and mechanical ventilation in recent
https://kat.cr/user/tahir99/
• Burns KE, Adhikari NK, Keenan SP, et al. Noninvasive posi- years, all aspects of the management of severe asthma should
tive pressure ventilation as a weaning strategy for intubated be mastered by the intensivist, including optimizing mechanical
adults with respiratory failure. Cochrane Database Syst Rev. 2010: ventilation in the face of large increases in airway resistance and
CD004127. propensity for dynamic hyperinflation.
• Burns KE, Meade MO, Premji A, Adhikari NK. Noninvasive ven- • Severe asthma exacerbation is defined by several, but not necessar-
tilation as a weaning strategy for mechanical ventilation in adults ily all, of the following features: dyspnea at rest, upright positioning,
with respiratory failure: a Cochrane systematic review. CMAJ. inability to speak in phrases or sentences, respiratory rate >30 breaths
2014;186(3):E112-E22. per minute, use of accessory muscles of respiration, pulse >120 beats/
min, pulsus paradoxus >25 mm Hg, peak expiratory flow rate <50%
• Celli BR, Cote CG, Marin JM, et al. The body-mass index,
airflow obstruction, dyspnea, and exercise capacity index in predicted or personal best, hypoxemia, and eucapnia or hypercapnia.
chronic obstructive pulmonary disease. N Engl J Med. 2004;350: • Altered mental status, paradoxical respirations, bradycardia, a
1005-1012. quiet chest, and absence of pulsus paradoxus from respiratory
muscle fatigue identify imminent respiratory arrest.
• Connors AF Jr, Dawson NV, Thomas C, et al. Outcomes follow-
ing acute exacerbation of severe chronic obstructive lung disease. • Airway wall inflammation, bronchospasm, and intraluminal mucus
The SUPPORT investigators (Study to Understand Prognoses and cause progressive airflow obstruction. Fewer patients develop
Preferences for Outcomes and Risks of Treatments). Am J Respir sudden-onset asthma from a more pure form of bronchospasm.
Crit Care Med. 1996;154:959-967. • Airflow obstruction causes ventilation-perfusion inequality, lung
• Jubran A, Tobin MJ. Pathophysiologic basis of acute respiratory hyperinflation, and increased work of breathing.
distress in patients who fail a trial of weaning from mechanical • Oxygen, β-agonists, and systemic corticosteroids are first-line
ventilation. Am J Respir Crit Care Med. 1997;155:906-915. treatments. Second-line treatments include ipratropium bromide,
magnesium sulfate, leukotriene modifiers, theophylline, inhaled
• Lindenauer PK, Pekow PS, Lahti MC, et al. Association of corti-
costeroid dose and route of administration with risk of treatment steroids, and heliox.
failure in acute exacerbation of chronic obstructive pulmonary • Noninvasive ventilation is potentially useful in hypercapnic
disease. JAMA. 2010;303:2359-2367. patients not requiring intubation.
• Mador MJ, Kufel TJ, Pineda LA, et al. Diaphragmatic fatigue and • Postintubation hyperinflation decreases right heart preload and
high intensity exercise in patients with chronic obstructive pulmo- results in tamponade physiology. This may present as tachycardia,
nary disease. Am J Respir Crit Care Med. 2000;161:118-123. hypotension, and even cardiac arrest. A ventilator strategy that
• National Institute for Health and Clinical Excellence. CG101 lowers lung volume decreases these potential complications.
Chronic Obstructive Pulmonary Disease: Management of Chronic • Treating airflow obstruction and prolonging the expiratory time
Obstructive Pulmonary Disease in Adults in Primary and during mechanical ventilation decreases lung hyperinflation.
Secondary Care. London: National Institute for Health and Clinical Expiratory time is prolonged by lowering minute ventilation and
Excellence; 2010. increasing inspiratory flow rate.
• Roberts M, Brown J, Kaul S, et al. Non-invasive ventilation in • Deep sedation allows for safe and effective mechanical ventilation in
chronic obstructive pulmonary disease: management of acute most intubated patients. Paralysis increases the risk of complications.
type 2 respiratory failure. Royal College of Physicians. http:// • Patient education, environmental control measures, and use of
www.rcplondon.ac.uk/pubs/contents/85efff68-58d4-4382-a48e- controller agents help prevent future exacerbations.
1e5f20c6187d.pdf. Accessed November 22, 2010.
• Schweickert WD, Pohlman MC, Pohlman AS, et al. Early physi-
cal and occupational therapy in mechanically ventilated, criti- Asthma is characterized by wheezing, dyspnea, cough, hyperreactive
cally ill patients: a randomised controlled trial. Lancet. 2009;373: airways, airway remodeling, and reversible airflow obstruction. In the
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1874-1882. United States, it has a prevalence of just over 8.0% and is responsible for
approximately 1.75 million emergency department (ED) visits, 450,000
• Wilkinson TM, Donaldson GC, Hurst JR, et al. Early ther- 2
apy improves outcomes of exacerbations of chronic obstructive hospitalizations and 3500 deaths. Underestimation of severity, poor
pulmonary disease. Am J Respir Crit Care Med. 2004;169(2): communication between the health care provider and the patient,
1298-1303. and failure to use a controller agent all contribute to morbidity and
mortality. While some studies indicate the incidence of respira-
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tory failure secondary to status asthmaticus requiring intubation and
mechanical ventilation is falling, it is essential the intensivist become
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familiar with the full spectrum of acute asthma, be able to determine the
REFERENCES stage and progression of this process, learn means to halt the progres-
sion of this syndrome, and to sustain patients who require mechanical
Complete references available online at www.mhprofessional.com/hall ventilation safely until underlying airway disease responds to treatment.

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