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Cardiac power output accurately reflects external cardiac work over a wide range of inotropic states in pigs.

ABSTRACT: BACKGROUND:Cardiac power output (CPO), derived from the product of cardiac output and mean aortic pressure, is an important yet underexploited parameter for hemodynamic monitoring of critically ill patients in the intensive-care unit (ICU). The conductance catheter-derived pressure-volume loop area reflects left ventricular stroke work (LV SW). Dividing LV SW by time, a measure of LV SW min-?1 is obtained sharing the same unit as CPO (W). We aimed to validate CPO as a marker of LV SW min-?1 under various inotropic states. METHODS:We retrospectively analysed data obtained from experimental studies of the hemodynamic impact of mild hypothermia and hyperthermia on acute heart failure. Fifty-nine anaesthetized and mechanically ventilated closed-chest Landrace pigs (68?±?1?kg) were instrumented with Swan-Ganz and LV pressure-volume catheters. Data were obtained at body temperatures of 33.0?°C, 38.0?°C and 40.5?°C; before and after: resuscitation, myocardial infarction, endotoxemia, sevoflurane-induced myocardial depression and beta-adrenergic stimulation. We plotted LVSW min-?1 against CPO by linear regression analysis, as well as against the following classical indices of LV function and work: LV ejection fraction (LV EF), rate-pressure product (RPP), triple product (TP), LV maximum pressure (LVPmax) and maximal rate of rise of LVP (LV dP/dtmax). RESULTS:CPO showed the best correlation with LV SW min-?1 (r2?=?0.89; p?

SUBMITTER: Abawi D

PROVIDER: S-EPMC6792198 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Cardiac power output accurately reflects external cardiac work over a wide range of inotropic states in pigs.

Abawi Dawud D Faragli Alessandro A Schwarzl Michael M Manninger Martin M Zweiker David D Kresoja Karl-Patrik KP Verderber Jochen J Zirngast Birgit B Maechler Heinrich H Steendijk Paul P Pieske Burkert B Post Heiner H Alogna Alessio A

BMC cardiovascular disorders 20191015 1

<h4>Background</h4>Cardiac power output (CPO), derived from the product of cardiac output and mean aortic pressure, is an important yet underexploited parameter for hemodynamic monitoring of critically ill patients in the intensive-care unit (ICU). The conductance catheter-derived pressure-volume loop area reflects left ventricular stroke work (LV SW). Dividing LV SW by time, a measure of LV SW min<sup>- 1</sup> is obtained sharing the same unit as CPO (W). We aimed to validate CPO as a marker o ...[more]

PMID: 31615415

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Project description:The aims of this study were to compare power output during a bench press throw (BPT) executed with (BPTbounce) and without (BPT) the barbell bounce technique, and examine the effect of cueing different barbell descent velocities on BPT power output in resistance-trained males. In total, 27 males (age 23.1 ± 2.1 years; body mass 79.4 ± 7.4 kg; height 178.8 ± 5.5 cm; and 4.6 ± 1.9 years of resistance training experience) were recruited and attended one familiarization session and two experimental sessions (EXP 1 and EXP 2). The force–velocity profile during maximal BPT and BPTbounce (randomized order) under different loads (30–60 kg) was established (EXP 1), and the effect of varying external barbell descent velocity cues “slow, medium, and as fast as possible” (i.e., “fast”) on the power output for each technique (BPT and BPTbounce) was examined (EXP 2). Comparing two BPT techniques (EXP 1), BPTbounce demonstrated 7.9–14.1% greater average power (p ≤ 0.001, ES = 0.48–0.90), 6.5–12.1% greater average velocity (p ≤ 0.001, ES = 0.48–0.91), and 11.9–31.3% shorter time to peak power (p ≤ 0.001–0.05, ES = 0.33–0.83) across the loads 30–60 kg than BPT. The cueing condition “fast” (EXP 2) resulted in greater power outcomes for both BPT and BPTbounce than “slow.” No statistically significant differences in any of the power outcomes were observed between “medium” and “slow” cuing conditions for BPT (p = 0.097–1.000), whereas BPTbounce demonstrated increased average power and velocity under the “medium” cuing condition, compared to “slow” (p = 0.006–0.007, ES = 0.25–0.28). No statistically significant differences were observed in barbell throw height comparing BPT and BPTbounce under each cuing condition (p = 0.225–1.000). Overall, results indicate that both bouncing the barbell and emphasizing barbell descent velocity be considered to improve upper body power in athlete and non-athlete resistance-training programs.

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Dataset Information

Cardiac power output accurately reflects external cardiac work over a wide range of inotropic states in pigs.

Publications

Cardiac power output accurately reflects external cardiac work over a wide range of inotropic states in pigs.

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