Ultrasonographic Assessment During Cardiopulmonary Resuscitation

Summary

Here, we present a US-CAB (Ultrasound, Circulation/Airway/Breathing) protocol for use during cardiopulmonary resuscitation (CPR). US-C evaluates the subxiphoid view of the heart and inferior vena cava. After intubation, tracheal US (US-A) and lung US (US-B) help confirm endotracheal intubation and proper ventilation.

Abstract

The US-CAB (Ultrasound, Circulation/Airway/Breathing) protocol integrates several sonographic techniques into a structured assessment of the circulation, airway, and breathing status of a patient during cardiopulmonary resuscitation (CPR) in an advanced life support-compliant manner. US-C provides a subxiphoid view of the heart, to look for potentially reversible causes of disease, such as pericardial effusion, pulmonary embolism, hypovolemia, and acute coronary thrombosis. Sonographic cardiac activity during CPR not only helps differentiate pseudo-pulseless electrical activity (PEA) from true PEA but also represents a higher chance of the return of spontaneous circulation (ROSC) and survival. Evaluation of the inferior vena cava (IVC) shows the fluid status of the patient and indicates the best methods to use for fluid resuscitation. If aortic dissection is suspected, a subxiphoid view of the aorta is suggested for identifying an intimal flap. Once intubation is done, tracheal ultrasound (US-A) at the suprasternal notch helps differentiate endotracheal intubation (one air-mucosal interface with one comet-tail) from esophageal intubation (double tract sign). Immediately following US-A, bilateral lung US (US-B) should be done to confirm proper bilateral ventilation using the lung sliding sign. In addition, US-C can be serially followed to see the dynamic changes in the cardiac chambers and IVC, or any cardiac contraction suggestive of ROSC. US-B can also detect coexisting lung or pleural pathologies without interfering with the performance of CPR. The main concern when implementing this method is maintaining high-quality CPR without delays in chest compressions when performing US-CAB. Rigorous training and continued practice are key to minimize any interruptions during resuscitation.

Introduction

Effective cardiopulmonary resuscitation (CPR) for cardiac arrest is key to successful revival of a patient. Circulation (C), airway (A), and breathing (B) are the three crucial components in either basic (BLS) or advanced life support (ALS). The evaluation of the C-A-B status during CPR basically relies on pulse checks, auscultation, and capnography¹. In true clinical conditions, however, CPR is often complex and chaotic, and these methods may have limitations^2,3. For example, the accuracy of pulse checks is often suboptimal even when performed by healthcare providers^4....

Protocol

This procedure was approved by the Institutional Review Board of the National Taiwan University Hospital and registered at ClinicalTrials.gov (NCT02952768).

1. Instrumentation

1. Use a US machine equipped with a curvilinear 2–5 MHz probe. A portable US is more suitable for CPR.

2. Personnel and their roles in the resuscitation team

1. Ideally, a resuscitation team should be comprised of six members: 1) a leader; 2) a member for airway management (A) and ventilation (B); 3) one for chest compressions (C); 4) one for defibrillation (D); 5) one for intravenous (IV) catheterization and ....

Results

US-C with subxiphoid evaluation of the heart displays a cardiac four-chamber view as shown in Figure 3A. At this point, detection of any of the three typical patterns suggestive of specific etiologies or reversible factors is possible.

Identify the presence and characters of pericardial effusion: If pericardial effusion is present, notice if the right heart chambers (i.e., the right atrium or even the right ventricle) are compressed. If compression of the right at.......

Discussion

US is a noninvasive, real-time, and readily available imaging modality in emergency and critical care settings. Application of US during CPR plays an important role in diagnosis, guidance of therapeutic intervention, or monitoring¹⁵. While many US protocols have been introduced for use with CPR, the US-CAB protocol complies with the sequence of advanced life support (ALS). It integrates important US techniques to detect possibly reversible causes of any issues, and to evaluate the C-A-B status dur.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Ultrasound	Cannon, Japan	SSA-550A	nil