[Evaluation of the fluid balance in geriatric patients-What contribution can abdominal ultrasound make?] / Evaluation des Flüssigkeitshaushalts bei geriatrischen Patienten ­ Was kann die Abdomensonographie beitragen?

The assessment of the fluid balance as well as the identification of hyperhydration and dehydration often represent a diagnostic challenge, especially in older patients. In principle, various diagnostic procedures and approaches are suitable for assessment of the various facets, by which such a disorder can be recognized. The contribution of abdominal ultrasound is described and evaluated in the context of the different diagnostic procedures. An overview of the current situation with respect to assessment of the vena cava is provided. In many respects there is no strict consensus concerning the thresholds of the individual measurements and the value of the different measurements. Currently, an orthograde diameter of the inferior vena cava > 2 cm is accepted as being a good indicator for hyperhydration. Less certain are analogously derived thresholds as indicators for dehydration.

Diagnostic efficacy of bedside ultrasound to detect dehydration in older patients attending an emergency care unit.

BACKGROUND: The diagnosis of dehydration in older patients remains a challenge because clinical and laboratory signs are unspecific. The use of B­Mode ultrasound of the inferior vena cava is proposed to aid in the diagnosis but data concerning diagnostic efficacy of bedside ultrasound are lacking. METHODS: In this study 78 patients ≥65 years old referred to the emergency unit of a university hospital and identified as being dehydrated by applying clinical signs were compared with a reference of 121 patients. The diameter of the inferior vena cava (IVC) was assessed by ultrasound while compressing the IVC during an inspiratory maneuver and the minimum and maximum diameter in M­Mode. RESULTS: Significant differences were found concerning compressibility, variability of the diameter assessed by M­Mode and the diameter during an inspiratory maneuver of the IVC (<0.001); however, a receiver operator characteristics (ROC) showed only moderate values for diagnostic efficacy for all these parameters where the best result was found for the inspiratory maneuver (Area under the curve [AUC] = 0.73). To reach a specificity of 0.8 to diagnose dehydration, a cut-off value of ≤0.4 cm for IVC diameter was suitable. CONCLUSION: Ultrasound of the IVC can easily be applied in a bedside setting and may be helpful in identifying dehydration in older patients; however, this remains challenging and a synopsis covering clinical and technical data is indispensable.