1. Acute Respiratory Failure
James Schneider, MD, Todd Sweberg, MD 
Critical Care Clinics 
Volume 29, Issue 2, Pages (April 2013)
DOI: /j.ccc
Copyright © 2013 Elsevier Inc. Terms and Conditions

2. Fig. 1
Pulse oximeter waveforms. Solid line: normal. Broken line: evidence of pulsus paradoxus. Arrow indicates inspiration and concordant decrease in peak of plethysmography tracing, indicating cardiovascular consequence of increased work of breathing, generating a more negative intrapleural pressure. This can be seen in upper airway obstruction (ie, infectious croup, postextubation) or lower airway obstruction (ie, asthma) and improves with appropriate therapy.
Critical Care Clinics  , DOI: ( /j.ccc )
Copyright © 2013 Elsevier Inc. Terms and Conditions

3. Fig. 2
Capnograph (time-based). Solid line: normal. Phase I: dead space (anatomic) gas exhaled from conducing airways; CO2 content near zero. Phase II: mixing of alveolar gas, which contains CO2. Phase III: plateau phase corresponds to pure alveolar gas. Phase IV: rapid fall due to inspiration, with negligible CO2. x and x': ETCO2. Dotted line: obstructed airway disease. Phase III slopes upward because of delay in emptying of alveolar gas from different lung units owing to increased airway resistance. The upsloping directly correlates with degree of obstruction, and improves with response to bronchodilator therapy.
(Data from Krauss B, Deykin A, Lam A, et al. Capnogram shape in obstructive lung disease. Anesth Analg 2005;100(3):884–8; and Yaron M, Padyk P, Hutsinpiller M, et al. Utility of the expiratory capnogram in the assessment of bronchospasm. Ann Emerg Med 1996;28(4):403–7.)
Critical Care Clinics  , DOI: ( /j.ccc )
Copyright © 2013 Elsevier Inc. Terms and Conditions