Cardell MAX-12 HD - Veterinary Instrumentation

CARDELL® MAX-12HD User’s ManualAPPENDIX 4 DIRECT BP MONITORINGMarc R. Raffe DVM, MS, DACVA, DACVECCPfizer Inc., St. Paul MNBlood pressure is considered an important component of patient monitoring inemergency and critical care medicine. Blood pressure is a product of severalcardiovascular parameters including cardiac output (stroke volume x heartrate), volumetric compliance of peripheral blood vessels (systemic vascularresistance) and effective circulating blood volume. Veterinary medicine hasembraced blood pressure measurement as an important monitoring tool for avariety of medical and surgical situations. In most cases, current clinicalpractice measures blood pressure by an indirect technique which relies onsurface pressure occlusion of a superficial artery using a pneumatic cuff and amethod to detect blood flow distal to the site of cuff occlusion. Accepteddetection methods to identify blood flow include auscultation, oscillometry,palpation, ultrasonic, and photoelectric methods. Although valuable, it haslong been recognized that all indirect methods have limitations in accuratemeasurement associated with both patient and operator factors. Also, indirectblood pressure measurement is not robust, meaning that it cannot be accuratelymeasured during low pressure and vasoconstricted states.Because there are limits to indirect blood pressure measurement, there isincreased interest in direct blood pressure monitoring in patients demonstratingabnormal physiology that may render indirect measurement techniquesinaccurate or impossible. Direct blood pressure measurement requiresintroduction of a catheter into an arterial or venous lumen and equipment andsupplies to transfer pressure from the catheter tip to ameasurement device. For this reason, direct measurement is technically moredemanding than indirect techniques but less prone to measurement error. Thepurpose of this presentation is to review the theory, practice, and techniques fordirect arterial blood pressure measurement in dogs and cats.Equipment needed for direct blood pressure measurementEquipment and supplies: Essential equipment and supplies needed for directblood pressure monitoring include arterial catheters (see below), side portcatheter adapter, low compliance extension tubing, three way stopcocks,pressure measurement device (transducer), pressure analysis and displaydevice (ECG/BP monitor), heparinized saline, and syringes/needles. For longM1.0 5-15-09123