Transpulmonary ultrasound dilution is an acceptable technique for cardiac output measurement in anesthetized pigs

Abstract

OBJECTIVE To evaluate cardiac output (CO) measurements using transpulmonary ultrasound (TPUD) technology and compare results with those of the gold standard, pulmonary arterial catheter thermodilution (PACTD), in 6 healthy anesthetized pigs during acute hemodynamic changes caused by manipulation of the blood volume. ANIMALS 6 healthy male Landrace pigs. PROCEDURES Over a period of 1 week, pigs were anesthetized with isoflurane, mechanically ventilated, and underwent instrumentation in dorsal recumbency. They were subjected to sequential experimental states during which the blood volume was manipulated so that the animals transitioned from normovolemia to hypovolemia (20% and 40% of blood volume depletion), back to normovolemia (autologous blood transfusion), and then to hypervolemia (following colloid bolus). During each volume state, CO measurements were compared between TPUD and PACTD. RESULTS The mean ± SD relative bias between TPUD and PACTD was 7.71% ± 21.2% with limits of agreement –33.9% to 49.3%, indicating TPUD slightly underestimated CO values, compared with values obtained with PACTD. The mean ± SD of the bias between the 2 methods was 0.13 ± 0.5 L/min. Only 5 of 36 (13.9%) TPUD CO measurements had an absolute value of relative bias > 30%. The percentage error calculated for TPUD was 29.4%. CLINICAL RELEVANCE Results suggested that TPUD measurements have acceptable agreement with PACTD measurements. Moreover, TPUD exhibits promising potential in being used interchangeably with PACTD for future hemodynamic research involving swine as species of interest.

Agreement between Electrical Cardiometry and Pulmonary Artery Thermodilution for Measuring Cardiac Output in Isoflurane-Anesthetized Dogs

“…Even though PATD is considered the de facto ‘gold standard’ in human and veterinary medicine [ 8 , 9 , 33 , 36 , 37 ], it is linked with well-known limitations [ 44 ] and complications [ 10 ]. The factors contributing to measurement errors and variability include injectate volume and temperature, intracardiac shunts, valvular dysfunction, catheter dead space, injection time, irregular respiratory patterns, concurrent IV infusions, and exogenous cooling or warming [ 44 ].…”

“…Using a literature search of veterinary studies comparing CO measurement techniques with the gold standard PATD [ 33 , 36 , 37 ], an a priori power analysis indicates that a sample size of six dogs is necessary to show a minimum 20% significant difference in CO during the induction of acute changes in hemodynamics carried out by the manipulation of blood volume, assuming a statistical power of 0.8 and an alpha level of 0.05 ( accessed on 1 September 2021).…”

Performance of four cardiac output monitoring techniques vs. intermittent pulmonary artery thermodilution during a modified passive leg raise maneuver in isoflurane-anesthetized dogs

“…To calculate bias, the difference between iPATD CO and CO values for each of the other methods (EC CO , APWA CO , TEE CO , and ED CO ) was expressed as a percentage of the average CO values between iPATD CO and the specific method. This relative bias was represented as a percentage of average CO values, utilizing a formula previously reported ( 24 ). Relative bias was considered positive when CO values were underestimated by other methods in comparison to iPATD CO , and negative when CO values were overestimated.…”

Ultrasound dilution cardiac output and echocardiography findings in anesthetized mature alpacas (Vicugna pacos) during normotension, hypotension and hypertension

“…The alpacas used in this study were not available for placement of a pulmonary arterial catheter and thus UDCO and ECHO were utilized even though they have not been validated for use in this species. The UDCO method has been validated in adult, pediatric and neonatal humans, sheep, dogs, neonatal and juvenile horses, and pigs [46][47][48][49][50][51][52]. Thus, it is likely that the results obtained in this study are accurate.…”