Autonomic, Noninvasive Blood Pressures in Students

The study conducted by Schell and Keith in 2007 is directed towards a hard core reality faced by medical practitioners on daily basis, as it can become unrealistic to determine the blood pressure in obese patients. Schell, is a DNSc, and Keith is a Ph.D. and thus both their qualifications match the standard of the research study they have conducted. The research article, “Comparison of forearm/ upper arm autonomic, noninvasive blood pressures in college students”, is published in a well reputed medical journal, having a reasonable impact factor. The abstract explicitly demonstrates the objective of the research study, a brief methodology, and a conclusion to the results obtained, and thus, is a concise and precise abstract.

The research problem depicts the necessity to find alternate areas of the arm to record blood pressure due to the unavailability of appropriate cuff sizes for obesity patients. The authors have proposed that blood pressure can be recorded on forearms, provided they are at level with the heart. The significance of the study is that patients who have their upper arms inaccessible, due to an injury for example, could have their blood pressures recorded. Likewise, obese patients could have their blood pressure recorded more conveniently. Validation of blood pressure measurement techniques have been recently called for in the United States and Europe (Pickering, 205; Jones, 2003; Tholl, 2004). This has been aggravated by the increased cases of high blood pressure in adolescents in the recent years, which was further coupled by an increase in number of obesity cases in this age group (Huang, 2003). The study was researchable, and a good and thorough scientific study was demonstrated in the paper. Since the study involved only recording data, with inputs only in terms of labor, and demonstrating the benefits of the results that would yield, this study was considered to be feasible.

The purpose of the research was clearly stated, and it was focused towards exclusively a particular objective i.e. to determine whether the blood pressures could be recorded in the forearm, and what the differences were statistically from the upper arm readings. Ethically, the study was intriguing, as this was just facilitating the obese patients, and thus, no ethical irregularities were found in the study. The authors included the rate of heart beat, when readings were taken in both areas, thus including another very important component of blood pressure.

Similar research studies conducted Sanger, Kahn, and Schell were some of the studies demonstrated. Previous studies by Singer (1999) and Schell (2005, 2006) were similar, except that older subjects wee employed. The authors had added a new angle to the previous studies. They used younger patients between 18-25 years of age, as their samples, in lieu of the elderly patients sampled in the previous studies. This was because of the high number of obese patients in this age range. The references employed were relatively up to date; the paper was published in 2007, and references of up to 2006 were depicted, which is credible. Primary sources have been used for comparison.

Theoretical framework is explicit, and explains the problem faced by nurses, due to unavailability of appropriate cuff sizes, blood pressure in obese patients cannot be determined, and an alternative area has to be identified where the readings statistically match the data recorded in the upper arm area. The relationship of the study is in perfect coordination to the nursing body of knowledge, and has tremendous implications.

The research objective is clear, concise, and precisely exhibits the problems that nurses face in their daily routine. The hypothesis denotes that the forearm and upper arm should yield similar data, if all conditions are similar, this is in coordination with the research problem, theoretical framework and review.

The statistical analyses conducted was paired t-test, using a high confidence interval of 99.999 %, which further authenticated the minor differences in data. Differences of more than 5mm Mercury are considered to be clinically significant (Turner, 2004). The variables under consideration were the diastolic and systolic readings from the upper arm and forearms, cuff size, circumference of the arm and heart rate of the sample were recorded. Independent demographic variables into consideration were the samples, age, gender, origin (white, Hispanic) and his/ her smoking habits. The person should have had no previous illness.

It was mentioned that the sample number was only 104 which was a small number under consideration. However, it was a totally random sample, which gave weight to the analyses. The study demonstrated inclusion criteria of data generation, as the samples’ blood pressure was recorded. It was observed that attrition took place in this series of experiment due to loss of the same sample. It would not have been possible to use the exact sample for future analyses, and each time, a fresh sample had to be used, which could have affected the authenticity of the results. Due to the young age group selected, mortality could not have been such a strong factor as attrition did. Prior to the experiment, approval was taken from the University’s human subject review board, and only then were fliers distributed.

The research design was a 2-way paired t-test, which was straightforward, and demonstrated a clear picture of the data generated. This was coupled with Pearson’s correlation analysis to determine the differences between readings in the forearm and upper arm. A third type of analysis, i.e. Bland-Altman analyses (Bland, 1986) was used to determine the level of agreement between forearm and upper blood pressure for individual subjects. The series of statistical tests were very appropriately used. This was an exclusively experimental study, and some ‘errors’ could have occurred due to the subjects emotional stability, when blood pressure was recorded, or the thickness of the skin could play a major role in the readings, as thickness of skin varies in each individual in the forearm and upper arm.

Measurements were recorded using a simple stethoscope where the mm Mercury levels were recorded—upper and lower readings were recorded for each individual—diastolic and systolic readings. It was made sure that the level of arm coincided with the heart level—and a mechanical table was used for proper arm leveling. A Dynamap 8100T vital signs monitor was used to record data of the mm Mercury level, and this also showed the rate of heart beat of each of the subject.

These instruments are used in the most modern hospitals, and are reliable sources of data generation for blood pressure and heart rate determination. The procedure for data collection and its statistical analysis is well explained in the research paper.

After a thorough investigation, the results obtained clearly indicated that there was a significant difference in the blood pressure recorded in the forearm and in the upper arm. The upper arm showed a significantly lower blood pressure reading, even within one minute of recording in the two regions. These findings were as expected; however, they eliminated the factors of illness and old age in blood pressure readings. The findings have explicitly been explained, with well thought-out reasoning proposed in the discussion. Results obtained are statistically significant, and level of error was 0.0001%, thus further authenticating the results, and eliminating any level of error.

The results are significant, and have many implications, such that the misconception of nurses has to be removed; they have to be particular in taking the blood pressure readings of patients only from the upper regions. They should be facilitated with larger cuffs, and be very particular as to how high or low in the arm the cuff is placed, so that false positive results of a patient having high/ low blood pressure can be avoided. False results could be detrimental. Thus, although it seems to be a petty issue, the enormousity of false interpretation of result, can become lethal. It has been clearly demonstrated that blood pressure taken in two different regions of the arm, could yield significantly different conclusions.

Limitations of the study were that, subjects were conveniently selected or requested for, from the same nursing school where the study was conducted. Thus, the sample was not as diverse as it should have been. Mostly (62%) of the subjects were females, white Hispanics. The sample could have been larger in size, and more diverse, if selected from a larger circle.

Suggestions proposed by the authors are that, the sample size should increase in number, and be more diverse; position of the arm should vary- the arm could be place in the subjects lap—like how it actually is when the blood pressure is recorded in clinics, in contrary to the ‘mechanical table’ that was used in this study. Likewise, another study could be conducted to determine predictors of differences in blood pressure in the forearm and upper arm. These future studies will add weight to the author’s findings. It would have been better if subjects of the same gender were sampled, for uniformity.

This study is beneficial to the medical practioners, as nurses are not very careful to the exact placement of the blood pressure cuff. Data generated clearly depicts the significantly high differences obtained just within 60 seconds of data recording in two different locations of the same arm. Thus, this study is an extremely useful one.

The article is professionally written, with immaculate level of English. There was no grammatical or spelling mistake observed throughout the article. There was a good display of results graphically, and all tables and graphs were properly labeled and titled. The margins were observed to be all in order, and references were well cited throughout the article. However, the font was observed to vary, as the complete article is typed in Arial, 12pt, justified; however, the Abstract was observed to be in Times New Roman, 12pt, not justified. Overall, the authors deserve credit for their commendable efforts in performing a good research study, and representing the study in a clear, comprehensive and scientific manner.

References

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Huang TTK, Harris KJ, Lee RE, Nazir N, Born W, Kaur H. Assessing overweight, obesity, diet, and physical activity in college students. Journal of American College Health. 2003; 52: 83-86.

Jones DW, Appel LJ, Sheps SG, Roccella EJ, Lenfant C. Measuring blood pressure accurately. JAMA. 2003; 289:1027-1030.

Pickering TG, Hall JE, Appel LJ, Falkner BE, Graves J, Hill MN, Jones DW, Kurtz T, Sheps SG, Roccellan EJ. Recommendations for blood pressure measurement in humans and experimental animals. Part 1: Blood pressure measurement in humans. Hypertension. 2005; 45: 142-161.

Schell K, Bradley E, Bucher L, Seckel M, Lyons D, Wakai S, et al. Clinical comparison of automatic, noninvasive measurements of blood pressure in the forearm and upper arm. American Journal of Critical Care. 2005; 14: 232 – 241.

Schell K, Lyons D, Bradley E, Bucher L., Seckel M, Wakai S, et al. Clinical comparison of forearm and upper arm automatic non-invasive blood pressures, supine and with head of bed raised 45 degrees: A follow-up study. American Journal of Critical Care. 2006; 15: 196-205.

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Tholl T, Forstner K, Anlauf M. Measuring blood pressure: Pitfalls and recommendations. Nephrol Dial Transplant. 2004; 19: 766-770.

Turner MJ, Baker AB, Kam PC. Effects of systematic errors in blood pressure measurements on the diagnosis of hypertension. Blood Pressure Monit. 2004; 9: 249-253.