Lung ultrasound predicts well extravascular lung water but is of limited usefulness in the prediction of wedge pressure.

BACKGROUND: Pulmonary congestion is indicated at lung ultrasound by detection of B-lines, but correlation of these ultrasound signs with pulmonary artery occlusion pressure (PAOP) and extravascular lung water (EVLW) still remains to be further explored. The aim of the study was to assess whether B-lines, and eventually a combination with left ventricular ejection fraction (LVEF) assessment, are useful to differentiate low/high PAOP and EVLW in critically ill patients. METHODS: The authors enrolled 73 patients requiring invasive monitoring from the intensive care unit of four university-affiliated hospitals. Forty-one patients underwent PAOP measurement by pulmonary artery catheterization and 32 patients had EVLW measured by transpulmonary thermodilution method. Lung and cardiac ultrasound examinations focused to the evaluation of B-lines and gross estimation of LVEF were performed. The absence of diffuse B-lines (A-pattern) versus the pattern showing prevalent B-lines (B-pattern) and the combination with normal or impaired LVEF were correlated with cutoff levels of PAOP and EVLW. RESULTS: PAOP of 18 mmHg or less was predicted by the A-pattern with 85.7% sensitivity (95% CI, 70.5 to 94.1%) and 40.0% specificity (CI, 25.4 to 56.4%), whereas EVLW 10 ml/kg or less with 81.0% sensitivity (CI, 62.6 to 91.9%) and 90.9% specificity (CI, 74.2 to 97.7%). The combination of A-pattern with normal LVEF increased sensitivity to 100% (CI, 84.5 to 100%) and specificity to 72.7% (CI, 52.0 to 87.2%) for the prediction of PAOP 18 mmHg or less. CONCLUSIONS: B-lines allow good prediction of pulmonary congestion indicated by EVLW, whereas are of limited usefulness for the prediction of hemodynamic congestion indicated by PAOP. Combining B-lines with estimation of LVEF at transthoracic ultrasound may improve the prediction of PAOP.

Renal resistive index: a new reversible tool for the early diagnosis and evaluation of organ perfusion in critically ill patients: a case report.

BACKGROUND: We reported a case of early detection of peripheral hypoperfusion trough the evaluation of a new index in intensive care: Renal Doppler Resistive Index (RRI). CASE PRESENTATION: We admitted a 76-year-old man who underwent ileostomy and hernioplasty because of an intestinal occlusion due to obstructive strangulated right inguinal hernia. The post-operative period was characterised by hemodynamic instability and he needed an invasive hemodynamic monitoring, administration of vasopressors and continuous renal replacement therapy (CRRT). Then, hemodynamic stability was obtained and vasopressors interrupted. RRI was lower than 0.7. In the eleventh post-operative day, despite stable macrocirculatory parameters, we found increased values of RRI. An abdomen ultrasound first and then a CT scan revealed the presence of bleeding from the previous ileostomy. Hence, the patient immediately underwent another surgical operation. CONCLUSIONS: RRI modification appears to be more precocious than any other hemodynamic, microcirculatory and metabolic parameter routinely used. RRI has been widely used to assess renal function in critically ill patients; now, we presume that RRI could represent a common and useful tool to manage target therapy in critical condition.

A simplified lung ultrasound approach to detect increased extravascular lung water in critically ill patients.

BACKGROUND: The quantification of B-lines at lung ultrasonography is a valid tool to estimate the extravascular lung water (EVLW) in patients after major cardiac surgery. However, there is still uncertainty about the correlation between B-lines and EVLW in a general population of critically ill. AIM: To evaluate a simplified lung ultrasonographic assessment as a tool to estimate the EVLW in critically ill patients admitted to a polyvalent intensive care unit (ICU). METHODS: Nineteen consecutive critically ill patients requiring mechanical ventilation and hemodynamic monitoring were enrolled. Lung ultrasonography and the thermodilution methodology (PiCCO system) were performed by two independent operators. The positive scan at lung ultrasound was defined by visualization of at least 3 B-lines. We then compared the number of chest areas positive for B-lines with the EVLW index obtained by the invasive procedure. RESULTS: A significant correlation was found between the number of lung quadrants positive for B-lines and EVLW indexed using both actual body weight (rho = 0.612 p = 0.0053) and predicted body weight (rho = 0.493 p = 0.032). Presence of more than 3 positive lung quadrants showed a good performance in identifying an EVLW index value >10 ml/kg of actual body weight(area under the ROC 0.894; 95% CI 0.668-0.987 p < 0.0001). Presence of of more than 4 positive lung quadrants indentified an EVLW index value >10 ml/kg of predicted body weight (area under the ROC 0.8; 95% CI 0.556-0.945 p = 0.0048). CONCLUSION: A simplified lung ultrasound approach can by used as a reliable noninvasive bedside tool to predict EVLW in emergency and critically ill patients.