Lab Report

Lab Technicians: Joanna Smith, Katherine Garcia, Megan Corradino and Zach Searle

Data Analysis: Taylor Douglas and James Tisch

Laboratory Goal: the labs were performed as part of a accumulation of experiments in order to advise the surgical physician of the physical changes his patient will under go before, during, and after surgery, as well as how to deal with the changes

Specific Studies (as outlined in laboratory data): Heart Rate and Blood Pressure response to external stimulus (ice water), as well as exercise (running in place)

Laboratory Experiment 1 (Heart Rate and Blood Pressure with Ice Water)

In this experiment, the laboratory subject’s baseline pulse and blood pressure were measured to create a basis for analysis. The data is as follows:

Table 1–Baseline Blood PressureTable 1–Baseline Blood PressureTable 1–Baseline Blood PressureSystolic pressure

(mm Hg)Diastolic pressure (mm

Hg)Mean arterial pressure (mm

Hg)104 71 106

Following the baseline tests, the subject was instructed to step into a bin of ice water while the pulse and blood pressure was measured again. The data is as follows:

Table 2–Blood Pressure Response to ColdTable 2–Blood Pressure Response to ColdTable 2–Blood Pressure Response to ColdSystolic pressure

(mm Hg)Diastolic pressure (mm

Hg)Mean arterial pressure (mm

Hg)112 70 70

Also, pulses were analyzed in order to determine the time recovery needed and how long the body takes to respond to such extreme external stimulus. The data is as follows:

Table 3Table 3Table 3

Condition Heart rate (bpm)

Time(s)

Resting heart rate 117Maximum heart rate 140 21Rebound heart rate 109 11.4

After the experiments were done, data analysis requests were made and responded to adequately as follows:

1.Describe the trends that occurred in the systolic pressure, diastolic pressure, mean arterial pressure, and heart rate with cold stimulus. How might these responses be useful in a “fight or flight” situation?

The systolic pressure was generally around 70 at the time of releasing the blood into the body at both times of normal and the ice water feet dunk. The diastolic pressure though, was a bit higher in the ice water foot dunk I’m thinking due to the heart pumping more blood throughout the body in hopes of warming the foot. The mean arterial pressure displays the perfusion pressure of the vital organs; in which the body systems generally slow down at the time of a fight or flight scenario. The heart rate generally slowed down at the time of the ice water situation, attempting at its best to keep the foot alive. These responses might be useful in a fight or flight situation because the vital body organs would slow down, not causing a waste of your energy; and also the heart would be pumping quickly trying to maintain a good temperature and speed up with adrenaline for survival.

2.As a vital sign, blood pressure is an indicator of general health. A high blood pressure (140/90 or higher) increases the risk of cardiovascular disease and strokes. Collect the systolic and diastolic pressures for the class and calculate the average for each. Rate the class average blood pressure using the follow scale:

The normal heart rate class systolic average had been 115.4, while the diastolic pressure hovered at a 69.8 average to which places the class at a Normal blood pressure. The average systolic pressure for the class at an exposure to ice water was 139.5, and the diastolic pressure had been 84.8 placing the class at a Pre-hypertension category.

3. How long after immersion did your heart rate reach its maximum value? Explain the physiologic mechanism that led to this change in heart rate.

The subject’s heart rate reached its maximum value at about 3 seconds from being in the ice water. Physiological mechanisms that led to this change in the heart rate were possibly the autonomic nervous system, which controls the nerve endings. The cold sensation ran through the subject’s foot nerve endings towards the brain and to the heart, increasing the heart’s contractions and preparing it for any given situation.

4. Describe the changes in heart rate that occurred after the maximum value. How can you explain the minimum heart rate value? How would you explain the heart rate variations seen in the remainder of the experiment?

After the maximum heart rate value it decreased even lower than the normal resting heart rate which was at 117, after the maximum, it went down to109. Minimum is your resting heart rate. It was normal, then up, then very low.

5. How long after the maximum heart rate did it take to arrive at your rebound heart rate? What can you say about the relative speed of physiologic response to a stimulus vs. the speed of mechanisms that are designed to maintain homeostasis?

About 11seconds. Our bodies finally go down to its relaxed heart rate once our body temperature adjusts.

6. If the heart rate is too slow there is inadequate blood pressure to maintain perfusion to the brain. This can lead to loss of consciousness (fainting). Keeping in mind the autonomic nervous system responses that you observed in this experiment, explain the sequence of events that results in a severely frightened person fainting.

There is not enough blood pumping through their body, so when a sense of being frightened occurs, shock sets in; slowing down body systems and lacking oxygen throughout the body. A light headedness appears, following blurred vision, in the end resulting with a weakened support and the body collapsing.

Laboratory Experiment 2 (Heart Rate and Blood Pressure with Exercise)

In this experiment, the laboratory subject’s baseline pulse and blood pressure were measured to create a basis for analysis. The data is as follows:

Table 1–Baseline Blood PressureTable 1–Baseline Blood PressureTable 1–Baseline Blood PressureTable 1–Baseline Blood PressureSystolic pressure

(mm Hg)Diastolic pressure

(mm Hg)Mean arterial pressure

(mm Hg)Pulse(bpm)

123 mm Hg 72 mm Hg 113mm Hg 70 BPM

Then, the subject was instructed to jog in place for 120 seconds, and the heart rate and blood pressure was recorded after exercise as follows:

Table 2–Blood Pressure After ExerciseTable 2–Blood Pressure After ExerciseTable 2–Blood Pressure After ExerciseTable 2–Blood Pressure After ExerciseSystolic pressure

(mm Hg)Diastolic pressure

(mm Hg)Mean arterial pressure

(mm Hg)Pulse(bpm)

135 mm Hg 98 mm Hg 122 mm Hg 97 BPM

Also, the heart rate at specific times and details were recorded in the following chart:

Table 3–Heart RateTable 3–Heart RateCondition

Resting heart rate (bpm) 17.1 BPMMaximum heart rate (bpm) 153.4

BPMRecovery time (s) 50 s

The Laboratory Analysis is as follows:

1. Describe the trends that occurred in the systolic pressure, diastolic pressure, mean arterial pressure and pulse with exercise. Assume that the stroke volume increased from 75 mL/beat to 100 mL/beat. Use this information and the change in pulse with exercise to calculate the change in cardiac output (stroke volume × heart rate) that occurred per minute.

The systolic, diastolic, mean arterial pressures and pulse all increased with exercise, most of the pressures went up by about 20 mmHg while the pulse increased by about 30 with the exercise. With a change in stroke volume of about 25 mL/beat, and a change in heart rate of about 27 BPM, we can conclude that the change in cardiac output was 675 per minute.

2. Pulse pressure is the difference between systolic pressure (peak pressure during active contraction of the ventricles) and diastolic pressure (the pressure that is maintained even while the left ventricle is relaxing). Describe the change in pulse pressure seen with exercise. Which component of the blood pressure is most responsible for this change?

The pulse pressure seen with exercise was 37 with the systolic pressure being at 135 mmHg and the diastolic pressure being at 98 mmHg throughout the exercise. The diastolic pressure is most responsible for the change due to the most change before and during exercise.

3. A change in pulse pressure can be seen in a variety of medical conditions. What would you expect to happen to the pulse pressure in the following examples?

(a) In atherosclerosis there is a hardening of the arterial walls.

I would expect the pulse pressure to increase because the elastin fibers would harden up and not effectively help the left ventricle.

(b) A damaged aortic valve does not seal properly and allows blood to flow back into the ventricle during diastole.

Pulse pressure would increase with a damaged aortic valve because the systolic pressure increases because the ventricle is pumping the leaky blood

and the normal blood it pumps, and the diastolic pressure falls due to the leak.

4. Normal resting heart rates range from 55−100 beats per minute. What was your/the subject’s resting heart rate? How much did your/the subject’s heart rate increase above resting rate with exercise? What percent increase was this?

Our subjects resting heart rate was 70 BPM, our subject’s heart rate increased to 97 BPM during exercise. The percent increase was about 390%.

5. How does your/the subject’s maximum heart rate compare with other students in your group/class? Is this what you expected?

Our subject’s maximum heart rate was 154 BPM. This was about average in our class, which was what I expected because our subject is involved in athletics.

6. Recovery time has been shown to correlate with degree of physical fitness. How does your/the subject’s recovery rate compare to that of your classmates? Is this what you expected?

Our subject recovered in about 50 seconds. She is involved in an athletic activity at school so the fairly quick recovery time was expected.

7. Congestive heart failure is a condition in which the strength of contraction with each beat may be significantly reduced. For example, the ventricle may pump only half the usual volume of blood with each beat. Would you expect a person with congestive heart failure to have a faster or slower heart rate at rest? With exercise?

It would beat slower at rest and faster with exercise due to the weakened state of the heart.

8. Medications are available which can slow the heart or speed it up. If a patient complains of feeling poorly and has a heart rate of 120 beats per minute, should you administer a medicine to slow the rate?

Maybe a low dosage of medicine because a resting heart rate of 120 BPM is above the average of 60-100 BPM.