Venous air embolism in removal procedure of CVC has an incidence about 0.2–1%, when this complication is suspected, a diagnostic test to visualize the air bubbles should be carried out immediately. For this purpose, ultrasonography is very sensitive at identifying air bubbles that may be undetectable on CT scan [2, 4, 5]. Transthoracic and transesophageal echocardiogram may detect a vascular air volume as small as 0.05 mL/kg and 0.02 mL/kg, respectively . A great advantage of POCUS applications is that ultrasound is a readily available bedside tool that could be used quickly for non-quantitative variables, allowing the identification of signs that may suggest cardiopulmonary compromise secondary to gas emboli migration such as dilatation of the right ventricle and inferior vena cava’s diameter. In severe cases, it would also detect abnormalities in the ventricular wall motion or right ventricular dysfunction [5, 6, 11, 12]. Any time that bubbles are found in both cardiac chambers, the clinician must consider the possibility of left side embolism with the risk of a cerebrovascular acute event, but also the mesenteric or renal arterial tree compromise. In this case, the patient developed a clinical and imagenological stroke with complete recovery and no sequelae. Under the clinical suspicion of cerebral air embolism, diagnosis must be confirmed with images such as the CT SCAN, which could be normal in the next hours of the event like in this case and thus completing cerebral studies with a MRI may be needed .
Once VAE diagnosis is made, definitive therapy can be considered, especially if the patient is hemodynamically unstable or complicated by end-organ damage . In case of hemodynamic instability, some studies have suggested that removing the air emboli from the right ventricle outflow tract, and hence maintaining circulation, can be made by increasing central venous pressures with intravenous fluids and patient positioning in Durant’s position (head low and right up) . However, the ideal position assumed by an affected patient remains controversial as recent animal studies have demonstrated a lack of improvement despite relocating air bubbles to the apex of the right ventricle by means of postural changes . Another strategy might be intermittent jugular venous compression, in order to prevent further air entry .
In most patients, therapy includes support measures like oxygen supply and in case of life-threatening respiratory failure, mechanical ventilation, vasopressors, and volume resuscitation. Hemodynamically unstable patients and those with end-organ damage or neurological deficits should be treated with definitive therapy such as hyperbaric oxygen, which may be delivered after a significant delay and still provides benefit [2, 3]. However, if this therapy is unavailable, aspiration of air directly from the circulation using intracardiac catheter aspiration with a multiple side-hole catheter such as a 5-French pigtail catheter or even direct aspiration with the tip of a previously positioned CVC approximately 1–3 cm above the sinoatrial node, may be a useful and safe treatment [1,2,3].
This case report demonstrates the value of POCUS application as a diagnostic tool in the hemodynamically unstable patient done by the attending physician beside the patient. Point-of-care ultrasound is time sensitive to get all the information relevant to help the clinician in the diagnosis and decision-making process, helping to rule out other differential diagnoses and performing the specific treatment; all aiming to decrease morbidity and mortality in these critical scenarios. Specifically, FATE protocol can be used as a screening and monitoring tool for significant cardiopulmonary pathologies specially in admitted patients with acute respiratory symptoms, with the potential of ruling in life-threatening conditions; and evaluate basic hemodynamic determinants such as preload, afterload, contractility, compliance, and relaxation [13, 14].
Particularly during coronavirus pandemic point-of-care ultrasound have been proved useful in early identification of shock mechanisms, assess changes in cardiac, renal or pulmonary function over time through quick routine examinations, perhaps in lieu of heart and lung auscultation, which can be challenging in critical care settings because of pronation, ambient noise, and personal protective equipment or could imply needing of patient mobilization in case of quantitative diagnostics approaches .
This tool, widely introduced in the last 4 decades in different settings like in the ICU, OR or the ER, has been well developed by many scientific societies with fantastic efforts to regularize and standardize the training and the practice of ultrasound applications.
We have the commitment to continue using and teaching this mandatory tool for all the clinicians who will be taking care of critical patients in critical scenarios.
Focused sonography of the heart, lungs, and deep veins is fast, highly feasible, and able to establish pathologic conditions in many admitted patients with acute respiratory symptoms. The clinical potential of focused sonography in an ED is as a tool for ruling in life-threatening conditions; at least as important, because of the high NPV, is its value as a standard rule-out examination in patients with respiratory symptoms.