The US-CAB protocol is a simple, structured protocol, that is used during resuscitation. It was named after the CAB sequences in the advanced life support guidelines. The US-CAB protocol can be used at during resuscitation.
It has positive impact on patient outcomes. Ideally, a resuscitation team should be comprised of a leader, a member for airway management and ventilation, a member for chest compressions, a member for defibrillation, a member for intravenous catheterization and medication, and a recorder. A sonographer should also be present as an independent member of the team who is well-trained and experienced in resuscitation ultrasound and who can intervene and interpret the ultrasound images in a timely manner without interrupting or delaying the resuscitation efforts.
When ultrasound is to be integrated into the CPR process, place a portable ultrasound machine in the caudal region of the patient, and set an alarm for every two minutes for CPR and every 10 seconds for pulse checks. To restrict the hands-off interval for pulse checks rhythm analysis, and simultaneous ultrasound evaluation to no longer than 10 seconds. At the start of CPR and at the end of the first five cycles of chest compressions use the subxiphoid four chamber view to check for pericardial effusion, the size of the left and right ventricles, and sonographic cardiac activity.
Then turn the probe 90 degrees, parallel to the long axis of the patient to measure the diameter of the inferior vena cava. To check the endotracheal tube location after intubation, place the probe transversely at the suprasternal notch and note the one air mucosal interface with one comet tail artifact for tracheal intubation. Move the probe to the lateral side of the neck to reconfirm the single tract sign.
And re-intubate, if there are two air mucosal interfaces with two comet tail artifacts. To check for proper ventilation, place the probe on both sides of the chest at the fourth to fifth intercostal spaces over the mid axillary line and look for lung sliding to evaluate pulmonary ventilation. If lung sliding is absent on one side, adjust the depth of the endotracheal tube until bilateral lung sliding is noticed.
Then repeat the cardiac ultrasound every two minutes when chest compression is stopped for pulse checks. Continue to repeat the airway and breathing ultrasounds after patient transport and bed transfer. If compression of the right atrium and ventricle is noted during cardiac ultrasound with subxiphoid evaluation, pericardiocentesis is indicated and should be performed immediately.
Pericardial effusion is also of diagnostic value. If the echogenicity is high or blood clots are present in the pericardial sac, the etiology could indicate serious complications. Cardiac ultrasound with subxiphoid evaluation of the inferior vena cava can be demonstrated by a vertical approach, and visual identification of the inferior vena cava diameter helps assess the fluid status of the patient.
The inferior vena cava can also be evaluated in the subxiphoid transverse view. Cardiac ultrasound with subxiphoid verification of the descending abdominal aorta can be approached via a vertical or transverse view. This optional evaluation is recommended if aortic dissection is suspected from clinical presentation or when hemopericardium is observed by cardiac ultrasound cardiac evaluation.
Endotracheal intubation is confirmed if a single tract sign is observed. If there is a double tract sign esophageal intubation is highly likely. Breathing ultrasound is usually performed immediately after airway ultrasound when auscultation or capnography is being performed but it can also be performed anytime during CPR when displacement of the endotracheal tube with one lung intubation is suspected or when specific etiologies such as pneumothorax or hemothorax need to be ruled out.
Although the scanning sequence is organized, the order can be changed according to the experience of the sonographer. Focused training and continued practice are essential to minimize processes during chest compressions. Maintaining a good image of quality is an important issue for further studies.
