Assessing Fluid Status of Peritoneal Dialysis Patients With Assistance of Lung Ultrasound

Assessing Fluid Status of Peritoneal Dialysis Patients With Assistance of Lung Ultrasound

• As studied previously, lung congestion is very prevalent however usually asymptomatic in dialysis patients. Fluid overload is associated with hospitalizations, worse cardiovascular outcomes and mortality in PD patients.
• The clinical exam is the only tool used currently to monitor volume status of PD patients, and has been found to have poor sensitivity and specificity for lung congestion compared to lung ultrasound. In current practice, patients are seen and examined monthly at their home dialysis units by the nurses. The nephrologist separately examines the patient monthly, possibly days to weeks after the nurse visit, and potentially only quarterly with the use of telehealth visits.
• Lung ultrasound is a relatively simple and cheap tool to assess for lung congestion, with little inter-operator variability and good reproducibility.
• There are limited studies of lung ultrasound in peritoneal dialysis, and none in the United States. Lung ultrasound may be useful as an objective measure of lung congestion in patients without signs or symptoms of fluid overload.

Aims of this study

• This study aims to determine the prevalence of subclinical fluid overload in peritoneal dialysis patients.
• The investigators aim to determine the added benefit of lung ultrasound to standard clinical practice of fluid management in PD patients.
• The investigators aim to assess the association of patient characteristics with lung congestion.
• The investigators also aim to assess the agreement between nurse physical exam and lung ultrasound for fluid overload.

Study Design:

• Cross-sectional study, inviting PD patients at 10 Northern CA home dialysis units to participate. One-time ultrasound done during monthly nurse visit between December 2019 and March 2020. All patients present for their monthly visit at participating home dialysis units on days in which ultrasound available will be eligible, unless they had already completed an ultrasound for the study.
• Eligible patients approached for informed consent
• Ultrasound method: 28 areas of the anterior and lateral thorax examined for B lines, need at least 3 B lines in each field to be counted- recorded for future validation
• Training: lung ultrasound training modules accredited by American College of Emergency Physicians, in addition to dedicated rotation of ultrasound training during internal medicine residency.
• Separate nurse clinical evaluation- yes or no, nurse blinded from ultrasound results
• Patient characteristics obtained from dialysis EHR and form 2728: Age, gender (male sex %), race, ethnicity, case of ESRD, dialysis vintage (mo), PD modality, BMI, DM (%), SBP, DBP, albumin , # of antihypertensives, use of diuretic, use of icodextrin, PD Rx, 24 hour urine volume, lung disease (%), heart failure (%)
• Lung ultrasound info documented in EHR along with nurse evaluation. If moderate-severe lung congestion on ultrasound, nephrologist notified in person, by phone or fax.
• Prescription changes from nephrologist (diuretic adjustment, dextrose concentration change, addition of icodextrin, or none) within 2 weeks tracked in EHR and/or in person with dialysis nurse
• Sample size calculation- assuming 30% subclinical fluid overload prevalence, 95% confidence interval of prevalence of subclinical fluid overload with 10% margin of error-> 81 patients

Inclusion Criteria:

• Peritoneal dialysis patients seen at participating Wellbound clinics in Northern California, present for monthly visit on days in which lung ultrasound available

Exclusion Criteria:

• Age <18, on peritoneal dialysis <3 mo, symptomatic lung congestion (reporting new or worsening shortness of breath over the past 4 weeks on enrollment), patient or nephrologist unwilling to participate in study