Avtor/Urednik     Geršak, Borut; Trobec, Roman; Krisch, Igor
Naslov     The effect of various clamping pressures on endothelium medated vascular relaxation: a pharmacological study
Prevedeni naslov     Vpliv tlakov žilne prijemalke na kontraktilno/relaksacijsko sposobnost obročkov torakalne aorte: farmakološka študija
Tip     članek
Vir     Zdrav Vestn
Vol. in št.     Letnik 67, št. 3
Leto izdaje     1998
Obseg     str. 133-7
Jezik     eng
Abstrakt     Background. The contraction/relaxation response of thoracic aortal rings clamped with two clamping pressures to KCI, noradrenaline and carbachol was studied. Methods. Clamp A had the tip pressure Pa=0.60 N/mm2 and clamp B Pb=5.16 N/mm2. In fifteen Wistar albino rats, weighting 328+-19 g (mean +-sd) the thoracic aorta was occluded for 15 minutes and then three vasular rings (2mm wide) were excised. The proximal unclamped rings served as a control. From distal rings the diameter of (n=15, dmin=1.51 mm, dmax=1.70 mm). The rings were challenged with cumulative additions of KCI (10-80 mmol/l) to measure the contraction. The cumulative relaxation to carbachol (0.01-100 micro mol/l) as a response to noradrenaline precontraction (0.1 micro mol/l) was determined. Results. A significant loss (p<0.05) of vascular relaxation in all clamped rings (clamped with Pa and Pb clamping pressures) was seen. No significant differences (p>0.05) were observed for contractonbetween clamped and control rings clamped with clamp A, however the rings clamped with clamp B showed significant reduction of contraction (p<0.05). No significant differences were seen from control rings between groups A and B (p>0.05), as well as from clamped rings between groups A and B (p>0.05) for both contraction and relaxation part of experiments. Conclusions. Endothelial vascular layers are much more susceptible to pressure injuries than was previously believed.
Izvleček     Izhodišča. V kardiovaskularni kirurgiji je dolgotrajna prehodnost žilnih anastomoz pogoj in hkrati tudi merilo uspešnosti operacij. Pri utečenih in splošno sprejetih postopkih se, zlasti v zadnjem času, veliko pozornosti posveča podrobnostim, ki lahko uspešnost kasnih pooperativnih rezultatov še dvignejo. Ena izmed takšnih je vpliv neposredne kirurške travme na žile z majhnimi dimenzijami, zlasti na arterijske koronarne premostitve (by-pass grafte), ki ohranjajo vse lastnosti žile, ki jo ima pred posegom, tudi po operaciji. Žilna stena je tista, ki ima pri vseh teh posegih odločilno vlogo, okvarjajo pa jo lahko neustrezna kirurška tehnika pri odvzemu žile in žilne prijemalke, saj vsak kirurški postopek, pri katerem prikažemo žilni endotelij, zahteva prekinitev krvnega obtoka v operiranem predelu. Metode. V eksperimentalni študiji na albino podganah Wistar smo z novorazvito merilo opremo za neposredno določanje tlaka žilne prijemalke na steno žile opazovali vpliv tlakov žilne prijemalke na kontraktilno/relaksacijsko sposobnost obročkov torakalne aorte. Za minimalni tlak žilne prijemalke Pm (ki zaustavi pretok krvi in preprečuje zdrsnjenje prijemalke s stene žile) smo definirali trikratni sistolični tlak. V poskusu smo uporabili dve prijemalki, ki se uporabljata v kirurški praksi: prijemalka A je imela tlak krakov na steno žile P približno enak Pm (P=0,60 N/mm2), prijemalka B pa je imela devetkrat večji tlak, kot je Pm (P=5,61 N/mm2). Petnajst albino podgan Wistar, z maso 328+-19 g (aritmetična sredina +- standardna deviacija), smo intubirali in umetno predihavali po predhodni anesteziji z intraperitonealno injekcijo pentobarbitalnatrija 0,1 mg/kg v bolusu. Na operacijski mizici smo jih nato položili na hrbet, jim tačke fiksirali z lepinimi trakovi inskozi levi četrti interkostalni prostor pristopili do torakalne aorte. (Izvleček prekinjen pri 2000 znakih.)
Deskriptorji     AORTA, THORACIC
VASOCONSTRICTION
VASODILATION
RATS, WISTAR
SURGICAL INSTRUMENTS
CARBACHOL
POTASSIUM CHLORIDE
ENDOTHELIUM-DERIVED RELAXING FACTOR