- Furthermore, in patients in the active arm, pre- and post-dialysis US-lung scans can be repeated at discretion of the nephrologist, i.e. whenever he/she believes that it can be useful applying this technique for monitoring the volume status of the patient, for example in a patient with <15 US-B lines who subsequently manifests a rise in body weight or in a patient who develops hypotension or frank hypotensive episodes during dialysis .