The role of clinical examination, chest X-ray and central venous pressure in volume assessment in critically ill patients: a comparison with PiCCO-derived data

Background

Assessment of preload and goal-directed resuscitation are crucial parts of ICU therapy. To assess preload, clinical parameters such as filling of the jugular veins, edema and pleural effusions as well as X-ray are used. In addition, haemodynamic parameters such as the central venous pressure (CVP), pulmonary arterial wedge pressure and PiCCO-derived global end-diastolic volume index (GEDVI) are determined. The GEDVI has been shown to be superior to pressure-based parameters with regard to volume responsiveness in several studies. However, PiCCO data are not available in all patients, and frequently clinical examination, CVP and chest X-ray are the first tools for preload assessment. It was the aim of our study to evaluate clinical assessment, X-ray and CVP with regard to the GEDVI and extravascular lung water index (ELWI).

Methods

In 86 patients of an internal ICU, clinical examination was independently determined by a physician and investigator not working in the ICU. Subsequently, chest X-ray (analysed by an experienced radiologist), CVP and PiCCO (Pulsion Company, Munich, Germany) measurements were performed and these data were correlated to clinical findings.

Results

Patients (n = 86; 34 females, 52 males) included 25 patients with cirrhosis, 18 patients with pancreatitis, 19 patients with sepsis; age 63.0 ± 15.5 years; APACHE II score 23.3 ± 8.4. Leg edema significantly correlated to CVP (r = 0.247; P = 0.038) and (negatively) to GEDVI (r = -0.258; P = 0.032). CVP and GEDVI were not associated: r = 0.035; P = 0.784. The ELWI significantly correlated to the degree of rales (r = 0.258; P = 0.016) and GEDVI (r = 0.557; P < 0.001). The ELWI and CVP did not correlate (r = 0.030; P = 0.785). Global clinical preload assessment (scale 1–10) was not predictive for GEDVI. Radiological assessment significantly overestimated the GEDVI (901.41 ± 139.76 vs 782.56 ± 183.80 ml/m²; P < 0.001) and underestimated the ELWI (7.22 ± 1.38 vs 9.77 ± 4.51 ml/kg; P < 0.001).

Conclusion

(1) Leg edema and increased CVP do not exclude preload deficiency determined by the GEDVI, which was overestimated by X-ray. (2) CVP and leg edema are poor predictors of the ELWI, which was significantly associated with audible rales but underestimated by X-ray.