de Beer VJ, de Graaff HJ, Hoekstra M, Duncker DJ, Merkus D. Integrated control of pulmonary vascular tone by endothelin and angiotensin II in exercising swine depends on gender. Am J Physiol Heart Circ Physiol 298: H1976 -H1985, 2010. First published March 26, 2010 doi:10.1152/ajpheart.00459.2009The lungs are now recognized as an active metabolic organ that is a major determinant of the plasma concentrations of the vasoconstrictors endothelin (ET) and ANG II. Several studies have suggested a complex interaction between ET and ANG II in the systemic and coronary vascular beds that is different at rest and during exercise. To date, the interaction between these vasoconstrictor peptides has barely been investigated in relation to the pulmonary vascular bed. Consequently, we investigated the integrated control of pulmonary vasomotor tone by ET and ANG II in 24 chronically instrumented swine (15 female and 9 male) at rest and during graded treadmill exercise. In the systemic circulation, ANG II type 1 (AT1) receptor blockade with irbesartan and mixed ET A/ETB blockade with tezosentan each produced vasodilation. The systemic vasodilator effect of ETA/ETB blockade was enhanced after AT1 blockade in female swine, whereas a trend toward an increase was observed in male swine. In the pulmonary circulation, AT1 receptor blockade had no effect on pulmonary vascular tone in male swine, whereas it resulted in an unexpected increase in pulmonary vasomotor tone in female swine. ETA/ETB receptor blockade did not result in a decrease in pulmonary vasomotor tone at rest but produced a decrease in vasomotor tone during exercise in both genders. This pulmonary vasodilation by ETA/ETB receptor blockade was enhanced after prior AT1 blockade in female swine but not in male swine. In conclusion, in both the systemic and pulmonary circulation of female swine, ANG II inhibits the vasoconstrictor influence of ET. This interaction is gender specific. The observation that plasma ET levels were not altered by AT1 blockade in either gender suggests that the interaction between these vasoconstrictors occurs locally in the vasculature. microcirculation; exercise DURING EXERCISE, systemic vascular resistance (SVR) decreases by 70 -80% as a result of vasodilation of the exercising skeletal muscle. In contrast to the substantial decrease in SVR, pulmonary vascular resistance (PVR) decreases only modestly (20 -40%) during exercise (20). Consequently, the marked increase in cardiac output together with a small increase in left atrial pressure results in a significant increase in pulmonary arterial pressure, which serves to increase the homogeneity of pulmonary perfusion during exercise, thereby improving lung gas exchange (20,29). In addition to its obvious role in gas exchange, the lungs are increasingly recognized as an active metabolic organ contributing to the production and degradation of many vasoactive peptides. Two of such peptides that are produced and/or metabolized by the lungs are endothelin (ET) and ANG II. ET B receptors in the lungs m...
The interplay of mechanisms regulating coronary blood flow (CBF) remains incompletely understood. Previous studies in dogs indicated that CBF regulation by KATP channels, adenosine and nitric oxide (NO) follows a non-linear redundancy design, and fully accounted for the exercise-induced coronary vasodilation. Conversely, in swine these mechanisms appear to regulate CBF in a linear additive fashion, with considerable exercise-induced vasodilation remaining when all three mechanisms are inhibited. A direct comparison between these studies is hampered by the different doses and administration routes (intravenous (IV) versus intracoronary (IC)) of drugs inhibiting these mechanisms. Here we investigated the role of KATP channels, adenosine and NO in CBF regulation in swine using identical drug regimen as previously employed in dogs. Instrumented swine were exercised on a motor-driven treadmill, before and after blockade of KATP-channels (glibenclamide, 50 mg/kg/min IC), and combination of inhibition of NO-synthase (Nw-nitro-L-arginine, NLA, 1.5 mg/kg IC) and adenosine receptors (8-phenyltheophylline, 8PT, 5 mg/kg IV), or their combination NLA+8PT+glibenclamide. Glibenclamide and NLA+8PT each produced coronary vasoconstriction both at rest and during exercise, while the combination of NLA+8PT+glibenclamide resulted in a slight further coronary vasoconstriction compared to NLA+8PT that was however less then the sum of the vasoconstriction by NLA+8PT and glibenclamide each. Thus, in contrast to previous observations in the dog, (i) the coronary vasoconstrictor effect of glibenclamide was not enhanced in the presence of NLA+8PT, and (ii) the exercise-induced increases in CBF were largely maintained. These findings show profound species differences in the mechanisms controlling CBF at rest and during exercise.
A 44-year-old man presented to our emergency department with a pharyngeal hemorrhage, 6 weeks after a total laryngectomy and extensive neck dissection. Immediate surgical intervention was necessary to stop massive arterial hemorrhage from the pharynx. The head and neck surgeon successfully ligated the common carotid artery during this procedure. We describe the anesthetic strategy and the thromboelastometry (ROTEM®)-guided massive transfusion protocol.
We describe a case of extensive soft palate ulceration after the use of an i-gel supraglottic airway device (Intersurgical Ltd, Wokingham, United Kingdom) during a knee arthroscopy in a 61-year-old man. He presented with pain and soft palate ulceration, which eventually required hospital admission because of dehydration. The pharynx healed completely within 3 months, with a change in taste as the remaining symptom.
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