A 64-year-old man comes to the emergency department with a 3-day history of fever, shortness of breath, and worsening productive cough. The patient also reports sharp, intermittent, right-sided chest pain. He has a history of hypertension and type 2 diabetes mellitus. The patient has smoked a pack of cigarettes daily for 20 years. Temperature is 38.9 C (102 F), blood pressure is 110/60 mm Hg, pulse is 114/min, and respirations are 32/min. The patient's pulse oximetry shows 86% on room air. Examination reveals diffuse crackles over the lung fields. Heart sounds are regular with no murmurs or gallops. Chest x-ray reveals bilateral consolidation and infiltrates. He is started on empiric intravenous antibiotics after obtaining cultures but requires endotracheal intubation due to respiratory failure. Which of the following is most reliable for confirming tracheal (rather than esophageal) endotracheal tube placement in this patient?

Question

A 64-year-old man comes to the emergency department with a 3-day history of fever, shortness of breath, and worsening productive cough.  The patient also reports sharp, intermittent, right-sided chest pain.  He has a history of hypertension and type 2 diabetes mellitus.  The patient has smoked a pack of cigarettes daily for 20 years.  Temperature is 38.9 C (102 F), blood pressure is 110/60 mm Hg, pulse is 114/min, and respirations are 32/min.  The patient's pulse oximetry shows 86% on room air.  Examination reveals diffuse crackles over the lung fields.  Heart sounds are regular with no murmurs or gallops.  Chest x-ray reveals bilateral consolidation and infiltrates.  He is started on empiric intravenous antibiotics after obtaining cultures but requires endotracheal intubation due to respiratory failure.  Which of the following is most reliable for confirming tracheal (rather than esophageal) endotracheal tube placement in this patient?

Quizplus · Accepted Answer

Explanation: Capnography (quantitative waveform or colorimetric analysis) is a noninvasive technique used to measure CO₂ concentration in the exhaled breath. It is the most reliable method for the verification of proper endotracheal tube (ETT) placement. A normal capnogram has a characteristic rectangular waveform with 4 phases. Any variation in waveform morphology and/or end-tidal CO₂ (EtCO₂) can provide diagnostic information about ventilation/perfusion or metabolic status. A normal waveform with all 4 phases after intubation indicates proper ETT placement, whereas a flat-line waveform typically indicates improper esophageal placement. A colorimetric EtCO₂ detector consists of litmus paper that changes color when exposed to CO₂. CO₂ exhalation from an ETT properly placed in the trachea will lead to a color change (purple to yellow), whereas an ETT improperly placed in the esophagus will not deliver CO₂ to the detector, resulting in no color change. (Choice A) An anteroposterior chest radiograph is useful for determining the depth of ETT in the trachea, but it cannot reliably exclude esophageal intubation. (Choices B and D) The auscultation of breath sounds in both lung fields and visualization of chest wall rise with assisted ventilation can be misleading as they are not specific for tracheal rather than esophageal ETT placement. Fogging of the ETT on exhalation occurs commonly after intubation but is also not a reliable indicator of tracheal rather than esophageal ETT placement. (Choice E) Experienced providers may sometimes be able to confirm tracheal placement of an ETT by visualization of it passing between the vocal cords. However, due to variable patient anatomy or fluid in the oropharynx (eg, blood, vomitus), clear visualization of the vocal cords is not always possible. Educational objective: Capnography (measurement of CO₂ concentration over time) is the most reliable method for verification of endotracheal tube (ETT) placement in the trachea rather than the esophagus. Clinical findings, including auscultation of breath sounds over both lung fields, chest wall rise with assisted ventilation, visualization of the ETT passing through the vocal cords, and fogging of the ETT on exhalation, are not reliable indicators of correct placement in the trachea. References: Comparison of three different methods to confirm tracheal tube placement in emergency intubation. (http://www.ncbi.nlm.nih.gov/pubmed/12107674) Verification of endotracheal tube placement following intubation. National Association of EMS Physicians Standards and Clinical Practice Committee. (http://www.ncbi.nlm.nih.gov/pubmed/10424864)

A 64-Year-Old Man Comes to the Emergency Department with a 3-Day