Misplaced and dislodged endotracheal tubes may be detected by the defibrillator during cardiopulmonary resuscitation

Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

The goal of therapy for bradycardia or tachycardia is to rapidly identify and treat patients who are hemodynamically unstable or symptomatic due to the arrhythmia. Drugs or, when appropriate, pacing may be used to control unstable or symptomatic bradycardia. Cardioversion or drugs or both may be used to control unstable or symptomatic tachycardia. ACLS providers should closely monitor stable patients pending expert consultation and should be prepared to aggressively treat those with evidence of decompensation.

Improving cardiopulmonary resuscitation quality to ensure survival

PURPOSE OF REVIEW

There is correlation between quality of bystander cardiopulmonary resuscitation and patient survival. Recent developments in defibrillator technology enable recording of cardiopulmonary resuscitation quality, and have shown quality of professional cardiopulmonary resuscitation far from guidelines' levels for factors such as chest compression depth and rate, ventilation rate, and pauses in chest compressions. The effects of cardiopulmonary resuscitation quality factors on patient survival are presently under scrutiny.

RECENT FINDINGS

Factors such as depth of and pauses in chest compressions immediately before defibrillation attempts affect outcome. Both immediate automated feedback on cardiopulmonary resuscitation quality and use of the same quality data during postevent debriefing improve cardiopulmonary resuscitation quality, and the combination appears to improve outcome. The increased awareness of quality problems, particularly unwanted pauses in chest compressions, has caused more emphasis on chest compressions in cardiopulmonary resuscitation protocols including the 2005 Guidelines. There is a growing number of reports of increased survival with these new protocols.

SUMMARY

Cardiopulmonary resuscitation quality affects survival after cardiac arrest. Reporting cardiopulmonary resuscitation quality data should be standard in all studies of cardiac arrest as effects of studied interventions can depend on or influence cardiopulmonary resuscitation quality. These data are also valuable in quality improvement processes both in-hospital and out-of-hospital.

Detection of malintubation via defibrillator pads

AIM OF THE STUDY

Endotracheal intubation is the preferred method to ensure proper artificial ventilation. Early detection of esophageal intubation is important for an individual patient's outcome. The aim of the study was to see if impedance measurements can be used to detect esophageal intubation, using the impedance measurement system of an experimental defibrillator.

MATERIALS AND METHODS

Patients who died at the emergency department of a tertiary care hospital were eligible to be studied. After death was declared, patients were ventilated with a predefined tidal volume alternately via the conventional tracheal tube and via an additionally tube placed into the esophagus. The lowest and respectively highest median impedance amplitude for the first three ventilations was used as cut-off to calculate predictive values.

RESULTS

We enrolled 10 patients (mean age 65 years (S.D. 14), 7 male) of whom 9 underwent CPR prior to death, 30% of the patients had a BMI>30. Severe lung-edema was present in 2 cases. The lowest tracheal impedance value was 0.736 ohms and the highest esophageal was 0.496 ohms. A ROC curve for this individualised approach gave an area under the curve of 1 (95% CI 0.001, 0.249).

CONCLUSION

There is a large and significant reduction in transthoracic impedance when the tube is malpositioned in the esophagus. It may therefore be feasible to detect malintubation via thoracic impedance changes as an aid to improve the survival of critical ill patients. Further investigations on a larger population are needed.

Transthoracic impedance changes as a tool to detect malpositioned tracheal tubes

BACKGROUND

Undetected malpositioned or dislodged ventilation tubes during cardiac arrest have fatal consequences, and no single method can detect the tube position reliably during such low-flow states. We wanted to test the ability of impedance changes as measured across the chest via the standard defibrillation pads to distinguish between oesophageal and tracheal ventilations in non-circulated patients.

MATERIALS AND METHODS

After the end of futile resuscitation transthoracic impedance was measured with a prototype defibrillator, and ventilation variables were collected with a spirometer-capnography unit during tracheal ventilations and after repositioning of the tube; during oesophageal ventilations for paired comparisons.

RESULTS

We registered 123 oesophageal and 178 tracheal ventilations in nine patients. Transthoracic impedance changes associated with ventilations were always larger during tracheal than oesophageal ventilations (mean difference 1.3 ohms (95% CI 1.0, 1.5), P<0.001), and all such changes above 1.2 ohms were associated with tracheal ventilations, while changes below 0.4 ohms always were associated with oesophageal ventilations. By subtracting 0.5 ohms from the individual mean transthoracic change associated with tracheal ventilations, tube position was predicted with sensitivity 0.99 and specificity 0.97.

CONCLUSION

Transthoracic impedance changes may be used to detect malpositioned and dislodged tubes also during situations without spontaneous circulation. Our predictive values must be retested in another population.