When the blood pressure of a patient is taken, it is common practice to measure it with the patient sitting in the up-right position with the arm resting on the arm of a chair and feet flat on the floor. The reference point for the measurement of BP is the right atrium, the so-called ‘heart level’ (Guyton, 1986). Though, the guidelines of the World Health Organistation/International Society of Hypertension (WHO/ISH) recommend that the BP be measured with the patient comfortably seated with the arms supported at heart level (1993). It has been proposed that BP should be measured in the sitting, standing, and the supine position (Netea 2003). It is suggested that the BP measurement from the ...view middle of the document...
The secondary focus of this study will be to test the difference in blood pressure levels at different locations of the body and compare them to a baseline blood pressure measurement obtained at the brachial artery. The third focus of this study will be to compare the distal and proximal blood pressure measurements in each of the body positions and compare the results of upper and lower extremities.
Purpose and Hypothesis
The purpose of this non-experimental research was to determine if significant differences existed in systolic, diastolic, and mean arterial pressure of blood pressure in the brachial artery when the patient is in the sitting position when compared to: the blood pressure of the dorsalis pedis artery in the sitting position, the blood pressure of the brachial artery in the supine position, and the blood pressure of the dorsalis pedis in the supine position. The researchers hypothesized that systolic, diastolic, and mean arterial pressures will be lower in the supine position than the sitting position and that brachial artery blood pressure readings will be higher than dorsalis pedis blood pressure measurements.
For this study, blood pressure is define as the pressure that the blood exerts against vessel walls that may be measured either directly by catheterization or indirectly by means of auscultation or oscillometric methods, measured in millimeters of mercury (mmHg) or water. The systolic pressure represents the force against vessel walls at the peak of cardiac contraction or systole, while the diastolic pressure represents the pressure when the heart is at rest, and the mean arterial pressure represents the average arterial pressure during a cardiac cycle (Porth, 2007). Fallaciousness of blood pressure results can occur from various causes, such as: incorrect cuff size(Schell, et al., 2005), where on the body the blood pressure measurement is being obtained from(Schell, Richards, & Farquhar, 2007), body position (Eşer, Khorshid, Yapucu & Demir, 2007), state of health of the patient, or imprecise placement of the blood pressure cuff on the extremity. Pickering and fellow authors suggest that the best method of obtaining blood pressure measurements is specific to each manufacturer’s recommendations and recommendations from the American Heart Association (Pickering, et al., 2005).
Various principles and laws of physics may describe the differences of blood pressure in the brachial artery and the dorsalis pedis artery. Srivastava explains in the article Principles of physics in surgery: the laws of ﬂow dynamics physics for surgeons – Part , “Poiseuille’s Law sets the limits of isovolaemic haemodilution, and enumerates limiting factors during fluid resuscitation” (Srivastava, 2009). In short, Poiseuille’s Law states that the smaller branching will in turn increase total pressure. Further, Bernoulli’s theorem or principle addresses how fluid passes over the surface of vessels; larger vessels have...