#4877 THE EFFECT OF NURSE-LED 8-ZONE LUNG ULTRASOUND GUIDED TITRATION OF DRY WEIGHT ON HYPERTENSION IN APPARENTLY EUVOLAEMIC HAEMODIALYSIS PATIENTS
Authors: Lee Grace , Chiu Jackie , Kha Umer , Khan Behram Ali , Ngoh Lee Ying Clara 
Published: June 2023

Abstract

Background and Aims
Hypertension related to subclinical volume overload is a common clinical problem in hemodialysis patients. Lung ultrasound (LUS) is a validated technique for minute titration of dry weight, but has limited adoption in clinical practice because it is currently a physician (nephrologist)-led methodology and time consuming with 24-lung zones needing to be imaged. This study aims to show that (1) a simplified 8-zone LUS protocol is effective at dry weight titration in clinically euvolaemic chronic haemodialysis patients, as determined by 24-hour ambulatory blood pressure monitoring (ABPM), and that (2) nurse-led LUS for dry weight titration is feasible and safe.

Method
This was a 6-week pre and post intervention study in 13 clinically euvolemic haemodialysis patients with chronic hypertension. 4 senior dialysis nurses with at least 4 years of dialysis nursing experience respectively were trained in LUS image acquisition and interpretation via a 1 day workshop by a certified Nephrologist and passed an image interpretation test. 8-zone LUS (which has been described by Volpicelli et al.[1]) was performed midweek, weekly. A Nephrologist reviewed all the acquired LUS images retrospectively. Dry weight was titrated down at a rate not exceeding 0.3 kg per week if LUS Kerley B lines exceeded 3 in any lung zone. All patients underwent 24-hour ABPM at baseline and after 6 weeks. Nurses underwent a post study qualitative survey to elucidate success factors and confidence in LUS technique.

Results
The study cohort was predominantly male (69%) and diabetic (92%), with an average age of 68 ± 10 years. The average time required for a nurse to complete 1 LUS scan was 3 ± 0.4 minutes. 75% of the cohort had dry weight reduction post-study, which ranged from 0.08 – 0.9% of initial dry weight. Correspondingly, the median number of ultrasonographic B-lines reduced from 4 to 3, although this did not reach statistical significance. Overall, there were reductions in 24-hour systolic BP (146.42±17.03 vs 139.08±12.40 mmHg; p = 0.067) and diastolic BP (72.75±11.79 vs 70.75±11.69 mmHg; p = 0.561). Similarly, there were trends towards improvements in pre- and post-dialysis systolic and diastolic BPs, although only pre-dialysis diastolic BPs showed statistically significant improvement (80±16.05 to 72.33±13.32 mmHg, p = 0.046). This may be related to small sample size. Nil adverse outcomes such as intra-dialytic hypotension, vascular thrombosis, cardiovascular events or fluid overload were reported during the study. 1 patient demised from pneumonia sepsis, which was deemed to be unrelated to the study. All nurses expressed confidence in LUS image acquisition and interpretation following the workshop. Their confidence was further bolstered by the end of the study. They also felt that point-of-care LUS was a useful skill for experienced haemodialysis nurses who were often responsible for day to day adjustment of fluid removal on dialysis.

Conclusion
We have demonstrated that nurse-led 8-zone LUS can effectively and safely titrate dry weight in chronic haemodialysis patients, as evidenced by improvements in 24-hours ABPM. Importantly, these results are similar to that of randomized controlled trials such as the LUST study where LUS was physician-led. There remains little doubt about the importance of LUS in volume assessment. In-depth studies are required to determine the competencies of, and risk-benefit assessment for nurse-led LUS, to improve the clinical relevance and penetrance of this tool.