Effect of isoflurane on aortic impedance in mice.
Isoflurane is the most commonly used anesthetic in mice. We studied the effect of low and high levels of isoflurane (also a potent coronary vasodilator) on aortic impedance in mice. Aortic impedance was determined using pressure and flow velocity signals at baseline (B, pentobarbital anesthesia), low (Isol, 1%), and high (Iso2.5, 2.5%) levels of isoflurane. Significant differences were observed in peak and mean flow velocities, systolic, diastolic, mean and pulse pressures at B and Iso2.5. However in impedance indices only peripheral vascular resistance was significantly different. No changes were observed in the harmonic components that represent pulsatile characteristics of the aorta. Peak left ventricular (LV) pressure was significantly lower at Iso2.5 when compared to B, but +/-dP/dt and tau (time constant of LV relaxation) did not change significantly indicating that LV contractility was unaffected. These results show that various levels of isoflurane cause significant changes in vascular hemodynamics and care must be taken to minimize these differences when using isoflurane as an anesthesia.
Reddy
Anilkumar K
AK
Department of Medicine, Section of Cardiovascular Sciences, Baylor College of Medicine and The Methodist DeBakey Heart & Vascular Center, Houston, TX 77030, USA. areddy@bcm.edu
Namiranian
Khodidad
K
Lloyd
Eric E
EE
Bryan
Robert M
RM
Taffet
George E
GE
Hartley
Craig J
CJ
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D001698:Biomedical Engineering; D003326:Coronary Circulation / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D007530:Isoflurane / Q000494:pharmacology*; D051379:Mice; D014655:Vascular Resistance / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
D018685:Anesthetics, Inhalation; D014665:Vasodilator Agents; D007530:Isoflurane