title: Estimation of extravascular lung water using the transpulmonary ultrasound dilution (TPUD) method: a validation study in neonatal lambs.
abstract: Increased extravascular lung water (EVLW) may contribute to respiratory failure in neonates. Accurate measurement of EVLW in these patients is limited due to the lack of bedside methods. The aim of this pilot study was to investigate the reliability of the transpulmonary ultrasound dilution (TPUD) technique as a possible method for estimating EVLW in a neonatal animal model. Pulmonary edema was induced in 11 lambs by repeated surfactant lavages. In between the lavages, EVLW indexed by bodyweight was estimated by TPUD (EVLWItpud) and transpulmonary dye dilution (EVLWItpdd) (n = 22). Final EVLWItpudmeasurements were also compared with EVLWI estimations by gold standard post mortem gravimetry (EVLWIgrav) (n = 6). EVLWI was also measured in two additional lambs without pulmonary edema. Bland-Altman plots showed a mean bias between EVLWItpudand EVLWItpddof -3.4 mL/kg (LOA ± 25.8 mL/kg) and between EVLWItpudand EVLWIgravof 1.7 mL/kg (LOA ± 8.3 mL/kg). The percentage errors were 109 and 43 % respectively. The correlation between changes in EVLW measured by TPUD and TPDD was r2= 0.22. Agreement between EVLWI measurements by TPUD and TPDD was low. Trending ability to detect changes between these two methods in EVLWI was questionable. The accuracy of EVLWItpudwas good compared to the gold standard gravimetric method but the TPUD lacked precision in its current prototype. Based on these limited data, we believe that TPUD has potential for future use to estimate EVLW after adaptation of the algorithm. Larger studies are needed to support our findings.
authors.affiliation: Department of Pediatrics - Neonatology, Radboud University Medical Center, Internal Postal Code 804, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands. s.vrancken@radboudumc.nl.
authors.forename: S L
authors.initials: SL
authors.lastname: Vrancken
authors.affiliation: Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Nusmeier
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: J C
authors.initials: JC
authors.lastname: Hopman
authors.affiliation: Department of Pediatrics - Neonatology, Radboud University Medical Center, Internal Postal Code 804, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: K D
authors.initials: KD
authors.lastname: Liem
authors.affiliation: Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: van der Hoeven
authors.affiliation: Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Lemson
authors.affiliation: Department of Pediatrics - Neonatology, Radboud University Medical Center, Internal Postal Code 804, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: A F
authors.initials: AF
authors.lastname: van Heijst
authors.affiliation: Department of Pediatrics - Neonatology, Radboud University Medical Center, Internal Postal Code 804, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: W P
authors.initials: WP
authors.lastname: de Boode
mesh_terms: D000465:Algorithms; D000818:Animals; D002302:Cardiac Output; D002404:Catheterization; D015633:Extravascular Lung Water; D005263:Femoral Artery / Q000473:pathology; D006439:Hemodynamics; D055370:Lung Injury / Q000473:pathology; D011654:Pulmonary Edema / Q000628:therapy; D015203:Reproducibility of Results; D012756:Sheep; D013815:Thermodilution / Q000379:methods*; D013818:Thermogravimetry; D014463:Ultrasonography
keywords: Cardiac output; Children; Dilution technique; Extravascular lung water; Hemodynamics; Indicator; Monitoring; Neonate