Introduction
Kathleen A. Schell & Julie Keith Waterhouse are the two authors for the research article. Both authors are qualified nurses from University of Delaware School of Nursing, Newark DE USA. Schell is DNSc, RN while Julie Keith is Phd, RN.
The title of the article is “Comparison of Forearm and Upper Arm: Automatic, Noninvasive Blood Pressures in College Students”.
Abstract is clearly written and well-summarize the main points of the study. The study is about comparing diastolic and systolic BPs from upper arm and forearm. As blood pressure is one of the important vital signs in accessing health condition, and in obese patients elevated BP is an important risk factor in cardiovascular disease. Hence, checking of BP is routine in normal health assessment. However, in obese patients as normal sized cuff would not either fit or will give an inaccurate readings some nurses and medical staff will use forearm to check BP. The current study was conducted to compare BPs of forearm and upper arm in order to evaluate the accuracy of the results obtained from forearm. Study revealed that diastolic and mean arterial pressure is significantly different between forearm and upper arm. While insignificant difference is found in systolic pressure of forearm and upper arm. The study suggest further investigation using large sample groups to further validate the results and investigation to find out result of these differences between the upper arm and forearm.
Research problem
The research problem is to analyze the differences in the readings of automatic noninvasive blood pressure measurements taken from the forearm and the upper arm. The significance of this study is that at times the upper arm is not accessible to take the blood pressure, so in such cases medical practitioners use the forearm to take readings. The upper arm may not fit the standard sized blood pressure cuff so the lower part of the elbow area, which is the forearm, is used for measurement of blood pressure. This study is further researchable, because up till now, not much research has been done to provide evidence of the use of the forearm for measuring blood pressure. The study carried out is a practicable one, with no risk factors or other complications.
Research purpose
The purpose of the research carried out in this article, is well stated, which is to compare automatic noninvasive measurements of blood pressures in the forearm and upper arm. It is focused and also inclusive of previous studies carried out to see the comparison of results of forearm and upper arm blood pressure readings. The study is ethical, and all the components are well-defined and clear.
Literature review
The article under critique is focusing on the measurement of blood pressure noninvasively in the forearm and upper arm. There have been previous studies done to probe into matters related to forearm and upper arm blood pressures, which have been included in this article. One such study carried out by Tachovsky was a comparison of indirect measurements of blood pressure attained through auscultation in the upper arm, with those of the forearm. Three measurements were taken with three minute intervals in a sample of 100 healthy female nursing students. The results obtained showed significant differences in the systolic blood pressure readings of the forearm and the upper arm.
Anatomical structures, like limb subcutaneous tissue and vessels also make a difference in the readings of the blood pressures of the forearm and the upper arm (Schell, K., Richards, J., & Farquhar, W., 2007).
This article includes a study carried out by Latman et al, who evaluated the use of a B/P Clinic, which was automatic and noninvasive, for the measurement of blood pressure of the forearm. 106 subjects were used for comparison of the readings obtained through the use of the B/P Clinic, and the auscultatory method in the upper arm. Results showed that the B/P Clinic method was both precise and accurate for measuring blood pressure using the forearm.
Another study conducted by Latman and Latman, showed the use of an automatic device for measurement of blood pressure at the wrists. The standard auscultatory method of attaining blood pressure through the upper arm, and the use of the automatic noninvasive wrist device were used for comparison of results of 150 subjects. The wrist device showed to produce results easily as compared to the traditional method, and it was a convenient form of blood pressure measurement at home.
It is evident from the studies mentioned that the forearm can be used for measuring blood pressure, if the use of the upper arm is not feasible for some reason (Singer, A., Kahn, S., Thode, H. & Hollander, J., 1999).
A recent study conducted by Emerick has been mentioned in the article, which shows the use of the wrist to measure blood pressure in 85 subjects. His conclusions showed that adjustments were needed in the positioning of the arm, for attaining results.
Though automated machines can produce inaccurate results in blood pressure readings, (Summers, K., 2007), they are still being used at large in hospitals and clinics. However, there is limited research available on the use of the forearm for determining blood pressures.
The studies mentioned in the article have been critiqued to an extent by the researchers, but the references used are not current. The studies date back to the nineties.
The current study shows that there is a difference in the readings obtained from the forearm and the upper arm. The two measurements are not interchangeable.
Theoretical framework
The theoretical framework for this study was expressed as well as implied in this article. It was a comparison of the results obtained in the readings of blood pressures taken from automatic noninvasive sources from the forearm, and the upper arm, using the auscultatory method. The relationships of the concepts of interest have been given, despite no defining terms used in the article.
Research objectives, questions and hypothesis
The objective of this research was to check and see if there is a difference in the readings of blood pressures taken from the forearm and upper arm. The comparison of automatic noninvasive readings of blood pressure in the forearm and upper arm was made.
Study variables
Independent variables are Age, gender, height, and color. Dependent variables are weight, circumference of upper arm and forearm, heart rate and other health conditions.
Samples
Small group of sample was studied including 104 college students. First the research proposal was approved by the University Human Subjects Review Board in March 2005. Participants were sent fliers via regular mail to their universities and where nursing program was conducted. Students were also emailed the invitations. Students who were interested were called on for to attend data collection sessions to be held in March and April 2005 for the duration of 4 weeks at school of nursing laboratories. Those who met inclusion criteria were given a complete explanation of the study and their consent was obtained.
Research design
The research design was appropriate, as hospital patients were taken for the sampling. The Welch Allyn Vital Signs 420 series monitor was used for taking the blood pressure measurements of these patients, from the forearm and the upper arm at the level of the heart. It was a descriptive and correlational study conducted in medically stable patients.
Measurement methods
The instrument that was used for this study was the Welch Allyn Spot Vital Signs 420 series noninvasive blood pressure monitor. It is an authentic tool for measurement, as it meets the SP-10 1992 AAMI standards for noninvasive blood pressure accuracy. Four new monitors were provided for the two-week data collection period.
A demographic form was made for each patient. This included essential factors such as age, sex, health related issues like cardiac risk factors, and other medical history. Retrospective chart reviewing was carried out, as charts were not accessible at all times of the data collection. The circumferences of the upper arm and forearm were taken, along with the cuff sizes, heart rates, blood pressures, and time intervals.
Data analysis was done by entry into Microsoft word, and then converted to SAS version 8.2. The Pearson correlation coefficient was used to measure the relationships between the blood pressure measurements, MAP and heart rates. Paired t tests were carried out to see the differences between forearm and upper arm readings. These tests and procedures seem sufficient for the comparison of readings for this study, since for further accuracy of the comparison, a Bland-Altman agreement analysis was undertaken. This was done to see whether the forearm can be used instead of the upper arm, to determine blood pressure measurements. It is recommended for clinical measurements.
Researchers interpretation on findings
The findings of the study relate to the study framework. The readings obtained were in accordance with the expectations. The t test results showed significant differences in the systolic pressures of the forearm and upper arm, but no vast difference was noted in the diastolic pressure results. Since this was a collective result, a further analysis for accuracy called the Bland-Altman agreement analysis was undertaken for individuals. The findings showed correlation between the measurements, but that does not indicate an agreement between the two variables.
There were great differences in the readings of 5 individuals, for which the cause could not be determined, but their forearm and upper arm measurements had a huge difference as compared to the rest of the subjects.
The limitations of the study include the following factors:
- The cardiac risk factors were obtained retrospectively, through the electronic chart review, which remained unrecorded by the hospital emergency departments during the examinations.
- The findings related to smokers is not authentic, as there were very few smokers and their findings were based on self-reports.
- Patients were seated while blood pressure was being taken. Thus patients could not be in a supine condition.
- Very small amount of patients who needed extra large cuffs for their upper arms, thus preventing generalizability of readings.
- The monitors present at hospitals for the readings of noninvasive blood pressure are not designed for measurements of the forearm.
Recommendations on usefulness of study in practice based on your critique
The writing is a scholarly piece, with relevant captions, and no spelling or grammatical mistakes. The APA style has not been followed exactly, but on the whole it is a good write up and is an easy read.
References
Kathleen, S., James R., William, F. The Effects of Anatomical Structures on Adult Forearm and Upper Arm Noninvasive Blood Pressures. Blood Pressure Monitoring 2007. 12(1):17-22.
Singer, A., Kahn, S, Thode, H. & Hollander, J. Comparison of Forearm and Upper Arm Blood Pressures. Prehospital Emergency Care, Vol 3:2, 123-126. 2008. Web.
Summers, K. Journal of Children’s and Young People’s Nursing Vol 1:2, 58-63. 2008.