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Background: Waveform capnography is considered the gold standard for verification of proper endotracheal tube placement, but current guidelines caution that it is unreliable in low-perfusion states such as cardiac arrest. Recent case reports found that long-deceased cadavers can produce capnographic waveforms. The purpose of this study was to determine the predictive value of waveform capnography for endotracheal tube placement verification and detection of misplacement using a cadaveric experimental model., Methods: We conducted a controlled experiment with two intubated cadavers. Tubes were placed within the trachea, esophagus, and hypopharynx utilizing video laryngoscopy. We recorded observations of capnographic waveforms and quantitative end-tidal carbon dioxide (ETCO 2 ) values during tracheal versus extratracheal (i.e., esophageal and hypopharyngeal) ventilations., Results: 106 and 89 tracheal ventilations delivered to cadavers one and two, respectively (n=195) all produced characteristic alveolar waveforms (positive) with ETCO 2 values ranging 2-113mmHg. 42 esophageal ventilations (36 to cadaver one and 6 to cadaver two), and 6 hypopharyngeal ventilations (4 to cadaver one and 2 to cadaver two) all resulted in non-alveolar waveforms (negative) with ETCO 2 values of 0mmHg. Esophageal and hypopharyngeal measurements were categorized as extratracheal (n=48). A binary classification test showed no false negatives or false positives, indicating 100% sensitivity (NPV 1.0, 95%CI 0.98-1.00) and 100% specificity (PPV 1.0, 95%CI 0.93-1.00)., Conclusion: Though current guidelines question the reliability of waveform capnography for verifying endotracheal tube location during low-perfusion states such as cardiac arrest, our findings suggest that it is highly sensitive and specific., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Introduction: Fresh frozen cadavers are effective training models for airway management. We hypothesised that residual carbon dioxide (CO2) in cadaveric lung would be detectable using standard clinical monitoring systems, facilitating detection of tracheal tube placement and further enhancing the fidelity of clinical simulation using a cadaveric model., Methods: The tracheas of two fresh frozen unembalmed cadavers were intubated via direct laryngoscopy. Each tracheal tube was connected to a self-inflating bag and a sidestream CO2 detector. The capnograph display was observed and recorded in high-definition video. The cadavers were hand-ventilated with room air until the capnometer reached zero or the waveform approached baseline., Results: A clear capnographic waveform was produced in both cadavers on the first postintubation expiration, simulating the appearances found in the clinical setting. In cadaver one, a consistent capnographic waveform was produced lasting over 100 s. Maximal end-tidal CO2 was 8.5 kPa (65 mm Hg). In cadaver two, a consistent capnographic waveform was produced lasting over 50 s. Maximal end-tidal CO2 was 5.9 kPa (45 mm Hg)., Conclusions: We believe this to be the first work to describe and quantify detectable end-tidal capnography in human cadavers. We have demonstrated that tracheal intubation of fresh frozen cadavers can be confirmed by life-like waveform capnography. This requires further validation in a larger sample size., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

During neonatal resuscitation, the routine use of capnography to verify correct placement of the endotracheal tube is not an established international practice. We present four cases that illustrate the successful use of immediate capnography to verify correct tracheal tube placement even in extremely low birthweight (ELBW) prematures (< 1000 g) during resuscitation. Based on this limited experience, we reached institutional consensus among paediatricians and anaesthesiologists that capnography should become standard monitoring during all endotracheal intubations in premature babies.

Objectives: Critically ill children often require endotracheal intubation prior to transport to a tertiary care center. Correct endotracheal tube (ETT) placement (trachea vs esophagus) and maintenance of ETT position during transport are of utmost importance. We evaluated the use of a Capno-Flo resuscitator (ventilation bag with a pH-sensitive colorimetric strip in the patient connector; Kirk Specialty Systems, Carrollton, TX) during transport of critically ill children., Methods: Thirty-nine intubations were evaluated in 38 patients (one patient was intubated twice) aged 1 day to 19 years (median age, 13 mo) and weighing 0.9 to 80 kg (median weight, 11 kg) who were intubated and transported by air ( = 26, 68%) and ground ambulance ( = 12, 32%). ETT position was confirmed by physical examination, pulse oximetry, and in some patients, arterial blood gases and chest roentgenograms. ETT position was also assessed using the Capno-Flo after six breaths after intubation and was read as positive if the color changed from purple to yellow (tracheal tube position) and negative if the strip remained purple (esophageal tube position). The Capno-Flo ambu-bag was used continuously during transport and evaluated by the nurses or respiratory therapists, who also completed a brief questionnaire., Results: Two esophageal and 37 tracheal tube positions were correctly identified by the device. There were no false-positive or false-negative results; the device was 100% sensitive and specific for the initial reading. It sometimes took longer to obtain this initial reading (> six breaths) in three patients. During transport, most personnel (36/38) noted minimal or no color change during inspiration and expiration, and therefore, it was not helpful in the continued verification of ETT position., Conclusions: The Capno-Flo resuscitator is useful in the initial confirmation of ETT position but not for continuous evaluation of ETT position during transport.

This study was undertaken to determine the time interval for changes in end-tidal CO2, oxygen saturation (SaO2), heart rate (HR), and blood pressure (BP) in response to an acute airway obstruction or hypopharyngeal extubation in a hyperoxemic model. Complete and partial airway obstructions were simulated with complete and partial cross-clamping of an endotracheal (ET) tube in five anesthetized, nonparalyzed, mechanically ventilated Yorkshire minipigs with initial PAo2 of > 400 mm Hg. Placement of the ET tube into the hypopharynx was performed to simulate accidental extubation. Both sidestream (SS) and mainstream (MS) capnography were used. Continuous pulse oximetry monitored SaO2, femoral arterial catheter monitored systolic BP, and electrocardiograph monitored HR. The time intervals for the capnograph wave to flatten and for the monitor to display zero were recorded after each airway alteration. The time interval to a change in the initial HR of 10 beats/min, a change of initial systolic BP of 10 mm Hg, and a change of initial SaO2 of 5% were recorded. Experiments were carried out for 180 seconds, and 25 trials were performed. HR, systolic BP, and SaO2 did not change for the 180-second duration of the trials. Complete obstruction produced a flattening of the SS and MS waveform in 8 +/- 2 seconds and 6 +/- 2 seconds, respectively. The SS and MS monitors displayed zero in 19 +/- 1 seconds and 68 +/- 7 seconds, respectively. Partial obstruction did not produce flattening of the wave or a monitor displaying zero. Hypopharyngeal extubation produced a flattening of the SS and MS waveform in 7 +/- 1 seconds and 7 +/- 2 seconds, respectively. The SS and MS monitors displayed zero in 18 +/- 3 seconds and 76 +/- 16 seconds, respectively. Continuous end-tidal CO2 capnography detects acute airway obstruction and hypopharyngeal extubation more rapidly than does pulse oximetry or vital sign monitoring in a hyperoxemic porcine model.