Halothane and enflurane significantly depressed potentiated-state strength to 0.45 and 0.61 g/mm2 respectively, while isoflurane preserved it at 0.95 g/mm2 compared to 0.91 g/mm2 at baseline.
Do inhalation anesthetics (enflurane, halothane, isoflurane) affect myocardial potentiated-state contractions in isolated rabbit papillary muscles?
In an in vitro rabbit model, isoflurane preserves myocardial potentiated-state contractions, whereas halothane and enflurane cause dose-dependent depression.
The effects of enflurane, halothane, and isoflurane on myocardial potentiated-state contractions were examined in a study in which each of the anesthetics was presented, in random order, to each of eight isolated rabbit papillary muscles. Post-rest potentiated-state contractions were elicited by imposing a stimulus at precisely timed intervals following a 2-Hz steady-state stimulus train. The strength of these contractions is known to be highly dependent on sarcoplasmic reticulum (SR) Ca2+ release. The increment in tension developed in potentiated state, as compared to the steady state, is directly attributed to the potentiation process, and is defined here as potentiated-state strength (PSS). Effects of enflurane, halothane, and isoflurane on the time course of development of the potentiated state were characterized, as were the effects of incremental doses of these anesthetics on PSS. Anesthetic gas phase concentrations that produced 50% depression of contractile tension at 0.05 Hz steady-state stimulation were 0.6% halothane, 1.4% isoflurane, and 1.6% enflurane. Muscles exhibited maximal PSS of 0.91 +/- 0.01 g/mm2 in the absence of anesthetics. Halothane (0.6%) and enflurane (1.6%) caused significant depression of PSS to 0.45 +/- 0.06 and 0.61 +/- 0.06 g/mm2, respectively, while isoflurane (1.4%) preserved PSS at 0.95 +/- 0.09 g/mm2. Concentration profiles showed that the depression of PSS by halothane and enflurane was dose dependent. Isoflurane, up to 2.3%, failed to depress PSS. The time interval for development of optimum PSS, 1.5 to 2.0 s, was unaffected by any of the anesthetics.(ABSTRACT TRUNCATED AT 250 WORDS)
DeTraglia et al. (Fri,) reported a other. Inhalation anesthetics (enflurane, halothane, isoflurane) vs. Absence of anesthetics was evaluated on Potentiated-state strength (PSS). Halothane and enflurane significantly depressed potentiated-state strength to 0.45 and 0.61 g/mm2 respectively, while isoflurane preserved it at 0.95 g/mm2 compared to 0.91 g/mm2 at baseline.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: