+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Disparity of isoflurane effects on left and right ventricular afterload and hydraulic power generation in swine

, : Disparity of isoflurane effects on left and right ventricular afterload and hydraulic power generation in swine. Anesthesia and Analgesia 87(3): 511-521

The interaction between myocardial and vascular effects of anesthetics has a potential impact on how these drugs influence performance of the heart. Most studies have focused on volatile anesthetic effects on the left ventricle (LV) and systemic circulation. Whether the right ventricle (RV) and pulmonary circulation respond in a similar fashion, however, is unclear. In the present study, we therefore examined the dose-related effects of isoflurane on LV and RV contractility and total afterload and related changes to simultaneous effects on the hydraulic power generated by each chamber. Two groups of swine were studied: one received no additional treatment before isoflurane (ISO, n = 6), and the other received hexamethonium, atropine, and propranolol to produce autonomic blockade before isoflurane administration (ISO+AB, n=4). For each experiment, measurements were made of RV and LV regional segment lengths and pressures, along with proximal aortic and pulmonary arterial (PA) blood flow and pressure during the administration of 0, 0.5, 1.0, and 1.5 minimum alveolar anesthetic concentration (MAC) isoflurane. Contractility was assessed by calculating the regional preload recruitable stroke work slope (PRSW). Afterload was characterized in both nonpulsatile and pulsatile terms by calculating aortic input impedance magnitude (Z). From these data, total arterial resistance (R), characteristic impedance (ZC), and vascular compliance (C) were determined with reference to a three-element Windkessel model of the circulation. Additionally, steady-state (WSS), oscillatory (WOS), and total (WT) hydraulic power output of each ventricle was calculated. In the ISO group, isoflurane produced a nearly threefold greater decrease of peak systolic pressure in the LV than in the RV, yet the dose-related decrease of regional PRSW was virtually the same in both chambers. In the aorta, isoflurane produced a maximal 25% reduction in R at 1.0 MAC and doubled C without a significant change inZC. Alternatively, PA R was increased from baseline at 1.0 and 1.5 MAC, whereas ZC was increased from all other values at 1.5 MAC. PA C was not altered by isoflurane. In ISO+AB pigs, PA ZC at baseline was higher than that evident in ISO animals but was not altered by isoflurane. In contrast, baseline aortic R was lower in ISO+AB pigs but was still modestly reduced by 1.0 MAC isoflurane. In ISO animals, WT and WSS from both ventricles demonstrated dose-related decreases, but the reductions in LV WT and WSS were greater than those for the RV at all doses. Accordingly, the power requirement per unit flow decreased for the LV but remained constant for the RV. WOS for both ventricles was also reduced by isoflurane. However, the LV WOS to WT ratio increased, which indicates that more power was lost to the system by pulsation. In contrast, reductions in RV WT and WOS were nearly parallel at all isoflurane doses, and the WCS to WT ratio was unchanged. In the ISO+AB group, isoflurane-induced alterations in LV and RV power characteristics were similar to those in the ISO group. These data indicate that, despite similar effects on biventricular contractility, isoflurane exerts qualitatively different effects on RV and LV afterload, in part via alteration in autonomic nervous activity, that influence the distribution of power output between steady-state and pulsatile components. Implications: In this study, we examined the effects of isoflurane on cardiac performance in swine and found that, although the drug depresses contraction of both the left and right ventricles similarly, it has different effects on forces that oppose the ejection of blood. These findings demonstrate that the two interdepenent pumps that comprise the heart can be influenced differently by anesthetic drugs.


PMID: 9728819

DOI: 10.1097/00000539-199809000-00002

Other references

Pifano, F.; Dias, E., 1940: Parasitismo natural do morcego Carolia perspicillata por um Schizotry-panum na Venezuela. Brasil-Medico, 54: 695-696

Subrahmanyam, C.B.; Gunter, G., 1970: New penaeid shrimp larvae from the Gulf of Mexico (Decapoda, Penaeidae). Crustaceana, 19: 94-98

Harasawa, M.; Koyama, K., 1957: The observation of antituberculous immunity by guinea pigs infected intraperitoneally. Kekkaku 32(3): 158-161

Shouse, M.N., 1988: Sleep deprivation increases thalamocortical excitability in the somatomotor pathway, especially during seizure-prone sleep or awakening states in feline seizure models. Pathological somatomotor system excitability and generalized seizures occur throughout the sleep-awake cycle but peak at different times in the amygdala kindling and systemic penicillin epilepsy models. Sleep loss increases seizure activity in bot...

Bal, K.; Bal, Y.L.llam, A., 2004: Gross morphology and absorption capacity of cell-fibers from the fibrous vascular system of loofah (Luffa cylindrica). Textile research journal 74(3): 241-247

Yang, S.; Meyskens, F.L., 2002: During human melanoma progression the AP-1 binding pairs are altered with replacement of FosB by Fra-1 and loss of c-Jun. Pigment Cell Research 15(Supplement 9): 81

Viveros, M., 1983: Many factors influence almond nitrogen needs. Almond facts 48(1): 52-53

Rövekamp, M.; Bowman, J.L.; Grossniklaus, U., 2016: Marchantia MpRKD Regulates the Gametophyte-Sporophyte Transition by Keeping Egg Cells Quiescent in the Absence of Fertilization. Unlike in animals, the life cycle of land plants alternates between two multicellular generations, the haploid gametophyte and the diploid sporophyte [1]. Gamete differentiation initiates the transition from the gametophyte to the sporophyte gener...

Corsini, E.; Gelati, M.; Calatozzolo, C.; Alessandri, G.; Frigerio, S.; D.F.ancesco, M.; Poiesi, C.; Parati, E.; Croci, D.; Boiardi, A.; Salmaggi, A., 2004: Immunotherapy with bovine aortic endothelial cells in subcutaneous and intracerebral glioma models in rats: effects on survival time, tumor growth, and tumor neovascularization. High-grade gliomas are aggressive tumors of the central nervous system characterized by endothelial cell proliferation and a high degree of vascularity. Conventional antitumoral treatments (i.e., surgery, radiotherapy, and chemotherapy) do not ach...

Manfrin, G.; Paolini, M.; Piccinetti, C., 1998: Demersal resources in the high and centre Adriatic Sea Le risorse demersali dellalto e medio Adriatico. Biologia Marina Mediterranea, 53: 96-108 (Parte Prima)