Ultrasonography in the Intensive Care Unit

Abstract

I N this issue of ANESTHESIOL-OGY, Manno et al. 1 present an evaluation of the clinical impact of an ultrasound protocol in inten-sive care unit (ICU) protocol. The study suggests that bedside ultra-sound examination by the attend-ing physician at ICU admission can detect significant, unsuspected abnormalities, with a major im-pact on diagnosis and treatment plans, thus obviating the need to transport patients to other facili-ties and improving healthcare quality. These data confirm that routine clinical examination, elec-trocardiography, and chest x-ray may not suffice to identify all sig-nificant underlying diseases. The study is interesting because there are few prospective evaluations of ultrasound in ICU. Manno et al. 1 used a fixed protocol examining by means of ultrasound: 1) optic nerve sheath diameter in comatose or deeply sedated patients to detect intracranial hypertension; 2) chest in different ventral-to-dorsal longitudinal and axial scans to detect pneumothorax, lung consolidation, intersti-tial syndrome, and alveolar edema; 3) heart by means of trans-thoracic echocardiography to detect valvular disease, left and right ventricle performance, and pericardial effusion; 4) abdo-men in different abdominal areas, from epigastrium to right iliac fossa, to detect peritoneal effusion, cholecystitis, hydronephro-sis, and parenchymal abnormalities; and 5) venous system of lower and upper limbs and neck with a mild compression ma-neuver to detect deep venous trombosis. Manno et al. focused on the number and type of ultrasound abnormalities and the role of ultra-sound to confirm or modify diag-nosis as well as to induce further investigations or perform a new procedure. A population of 125 consecu-tive critically ill patients admitted in a general ICU were included within 12 h from admission. Ul-trasound findings modified initial diagnosis in 26% of patients and confirmed initial diagnosis in 58% of patients, whereas it was not ef-fective in confirming or modifying the diagnosis in 14% of patients and missed the diagnosis in 2% of patients. The findings of ultra-sound examinations induced fur-ther investigations in 18% of pa-tients and modification of medical therapy in 39% of patients includ-ing invasive procedures. No corre-lation was found between number of ultrasonographic findings, mor-tality, Simplified Acute Physiol-ogy Score II, and length of ICU stay. Patient-and environment-re-lated sonography limitations had little influence on the majority of examinations. Interestingly, the ultrasound examination revealed a high prevalence of unsuspected clinical abnormalities in acute heart failure, such as valvular disease and lower ejection frac-tion in septic shock lung consolidation. However, because the study relied only on transthoracic echocardiography, the true prevalence of cardiac ultrasound abnormalities may have been underestimated. New unexpected findings in the abdom-inal and venous system or neurologic abnormalities were rare. There are several applications of ultrasonography in the critically ill patients at the bedside, including evaluation of alveolar recruitment and positive end-expiratory pressure-induced lung reaeration, during mechanical ventilation, in more severe hypoxemic patients; 2 evaluating volume load Image: ©istockphoto.com.