Fine
From: Memorandum
To:
Dr. K. Harbison, R. Bormann
Re:
Date: 07:34:00 BE-525 Lab 1 Results
In order to help reinforce the concepts of blood properties in the body from classroom lectures, today in lab we learned to measure blood pressure, pulse rate and blood oxygen content. Through these clinical measurements of fluid mechanics we were able to see what exactly affects each fluid property, and thus learned how fluid mechanics affected our personal health.
CONFIDENTIAL
Our first objective was to use a sphygmomanometer cuff and stethoscope to determine the systolic and diastolic pressures of the participant. This was done by placing the cuff around the participants bicep, inflating it until the pressure was higher than his systolic pressure, and then slowly releasing the gas from the cuff until Korotkoff sounds were heard through the stethoscope placed on the brachial artery. This was repeated five times, and the results were as follows: Blood Pressure Results Participant Sex Age Mean Systolic Pressure Standard Deviation of Systolic Pressure Mean Diastolic Pressure Standard Deviation of Diastolic Pressure Estimated Accuracy of Measurement K. Harbison Male 21 125.4 3.21 85.4 4.51 2.0mmHG
In comparison to the graph above, the participants blood pressure values do fall within the standard deviation of the norm for his age. The diastolic pressure is a little high for a 21 year old however, which could be an indication of hypertension in later years. This high value is believed to be caused by school-induced stress, unhealthy habits, and human-error induced into this part of the lab due to the ease at which values could be manipulated such as altering arm elevation and breathing patterns.
1
07:34:00 Our second objective was to use a Datex-Ohmeda oximeter to measure both the percentage of oxygen saturated hemoglobin in the resting and active heart rate. Both analyses are very important in judging overall health. An oxygen saturation that is too low could be a forewarning of future problems. Heart rate is an important indication of future complications because tachycardia or bradycardia, disorders where your heart either beats too fast or too slow, can lead to death if not treated promptly. After connecting the Datex-Ohmeda oximeter to the end of the participants index finger and waiting for the results to level out, the heart rate and percentage of oxygen saturated blood were recorded. Our initial analysis indicated that 98% of the hemoglobin was saturated with oxygen, and the resting heart rate of our participant was 76 beats per minute (bpm). It should also be noted that the participant during this second half of the lab was R. Bormann, so the previous suggestions a of slightly-high blood pressure from K. Harbison should not be used towards any conclusions for this section. The results of our initial analysis were within the range of what was expected. The next step in this section was to see if the participant could successfully lower the oxygen saturated hemoglobin count by holding his breath. After multiple tries from both participants, it was concluded that it is not possible, for us at least, to voluntarily hold ones breath long enough to affect percentage oxygen saturation. When a participant completely vacated his lungs of air before holding his breath, there was an indication that the oxygen saturation count may have gone down a percentage. However, because the amount of time the participant could hold his breath using this method was so short, it does not seem like a strong conclusion can be made. Although oxygen saturation could not be voluntarily manipulated at ease, pulse rate was shown to be an extremely variable parameter. The lowest recorded (resting) heart rate was 76 bpm, which was nearly doubled to 130 bpm after a short jog down the hallway. Oxygens primary role in the creation and utilization of energy within the body is the reason why heart rate is so variable, for the heart must accommodate the rate of oxygen expense in active muscle tissue by increasing the flow rate of oxygen-saturated blood. The oxygen saturation stays near the same during activity as in rest due to how the increased oxygen usage in muscles is balanced out by the increase in breathing and pulse rate. Although these trials were performed while trying to minimize the most error possible, we have reason to believe that some error is inevitable. Firstly, as light enters a medium of a different density, reflectivity or color than that of which it left, it is bent and refracted, thus affecting the wavelength. Therefore, the color of ones skin would affect the results, for the light used by the oximeter would be impeded by the darker colored skin. The thickness of skin could theoretically affect the results as well; however we believe the differences in skin thicknesses normally are to be so small that these affects can be considered negligible. Finger thickness would not affect the results, unless a thick finger has thicker skin, because the light is not actually going all the way through the finger. And lastly, we believe that the heart rate measurement can come to different conclusions based on whether the participant is inhaling or exhaling during the evaluation. Because inhalation requires energy to perform (moving the diaphragm to cause lower pressure in the lungs), the heart has to beat faster to supply oxygen to the necessary muscles.
2