Would manual monitoring of blood pressure be more accurate than machinery monitoring in adult medical patients for detecting variations in blood pressure?
Introduction
Today’s health care applies evidence based practice in patient care with the purpose of easing the clinical decision making with standard practice and provide high quality care to patients. Evidence Based Practice is a problem solving method in clinical care on the basis of best available findings from patient preferences, clinical expertise and sound evidences. EBP provides best clinical decision making and better outcomes to patients, than normally designed research studies. The intention of this activity is to identify evidences for answering the research question of would manual monitoring of blood pressure be more accurate than machinery monitoring in adult medical patients for detecting variations in blood pressure? The collection of relevant information suggests that the use of manual monitoring of blood pressure helps to provide the ability to the health practitioners to offer the patient care with evidence support.
It is imperative to monitor the blood pressure in every clinical setting to assess the physical condition and it is of vital importance to consider the measurements in clinical decision making (Bern et al. 2009). As shown by Heinemann et al (2008), the accuracy and the reliability of the method adopted for monitoring the blood pressure preclude the possibility of unnecessary complication arising from misdiagnosis or overdosing. The modern technology paved way for the development of sophisticated devices for blood pressure monitoring which are currently available (Bern et al 2007). However, the mercury sphygmomanometer is the ‘gold standard’ of blood pressure observation. The study tried to explain the trustworthiness and dependability of the auscultatory method in comparison with oscillometric method with literature support.
Literature Search Methodology
The usual practices adopted for monitoring blood pressure is manual checking with sphygmomanometer. But, today’s high stressful working atmosphere with lack of time demands advanced techniques to reduce the work load of health practitioners and provide efficient care to patients. Then also, most of the practitioners are following manual monitoring of blood pressure to avoid inconsistencies. The purpose of this study was to analyses the fluctuations in systolic, diastolic and arterial blood pressure with heart rate by using automated and manual blood pressure devices.
The searching process of evidence from literature mainly focused in databases such as CINHAL, Pubmed, Internurse, Ovid, science direct, Emerald, British index, etc. The search also included different journals that related to blood pressure and vital signs monitoring. The key word used is blood pressure, pulseoxymeter, sphygmomanometer, vital signs and blood pressure monitoring.
Results from literature search
The searching process begins with choosing PubMed from A to Z databases in electronic library. There were so many options available, in which PubMed Central selected. The keyword used for initial searching was ‘vital signs monitoring.’ About 5261 results were found. But nothing was relevant to searchable question. Again continued the searching process by changing the keyword to ‘blood pressure monitoring’ and focused more in automated blood pressure monitoring .Hence one article found supporting the researchable question. Moreover, the keyword changed to ‘accuracy of manual monitoring of blood pressure, which applied in another data base Cinhal with option of full test. From 34623 results, three articles were suitable for research question. Others were excluded, because they were not primary article or population was different or some were not comparing automated and manual blood pressure monitoring. The searching directed in to Ovid database with the same key word and two articles were completely relevant to the question. Furthermore, Science direct was selected and some more articles were found, among that few could not open because these articles require extra login password. Moreover, all the available supportive articles were not in Portable Document Format and two were supportive. Ultimately, searching in journals, especially nursing journals provided relevant articles to the research question, but they are already revealed in Cinhal database.
The structured searching also used the same keyword “accuracy of manual blood pressure monitoring’ in Cinhal database. This search strategy gave three relevant articles and again with Boolean operator “And” to get more relevant article by shortening the research process in particular area and “OR” for expanding the research to related areas. However, there was no significant improvement happened in searching; the resulted articles were same as to the initial search. This Boolean operator again used in advanced research of Science direct, which results around 145 articles and one is partially supporting the question and another is agreed with the effectiveness of manual monitoring of blood pressure.
The Evidence:
Five studies were chosen from different journals to prove the superiority of manual monitoring of blood pressure than machinery monitoring. The five articles are conducted in different years by using different research method and design. The main purpose of all the five chosen articles is to assess the equivalence of the two methods namely automated and manual blood pressure monitoring. With the aid of the searching process five articles were selected. The critical evaluation of five articles helps to reach in to a conclusion. The critical evaluation involves the analysis of sample techniques, data collection and data analysis strategies and the final results of each study.
The five selected literatures for critical review are primary article from the period 1996 to 2010. Out of these, three studies (by Jones et al.1996, Landgraf et al. 2010 and Yung and Lau, 2001) are quantitative and two studies (by Bern et al. 2009 and Heinemann et al. 2008) are randomized control trial. Quantitative research is an objective, formal, systematic process in which numerical data are used to quantify or measure phenomena and produce findings (Carr, 1994).Meanwhile, Sibbald and Roland(1998) stated that, Randomized controlled trial is a thorough method of assessing whether a cause-effect relation persists between intervention and consequence and for evaluating the cost effectiveness of a treatment.

In all five articles, the samples were adults. The intended strength available was adequate except in the study of Heinemann et al. (2008). All the three quantitative researches recruited samples randomly from the study population and allocated them randomly for performing procedures. As well, the ethical strength and reliability of quantitative studies are more compared to others and generally attained by informed consents (Carr, 1994). But, out of five articles, informed consent was obtained only in the studies of Heinemann et al. (2008) and Jones et al. (1996). Moreover, the two randomized studies were well designed, conducted and reported as well as conserves the rights of samples. In controlled trials, participants, investigators and analyzers of both studies remained unaware of the interventions throughout the study. This approach was introduced to prevent the risk of interfering the results with their cognition and experience (Day and Altman 2000).
The sample characteristics

Research: 1 (Bern et al. 2007)

The study had 126 medical in-patients, including male and female in a community hospital. The study introduced a few more subjects with irregular heart rates for appraising any difference in the accuracy of two methods of blood pressure monitoring in such types of individuals. This study necessitates additional researches in different situations for confirming the result.
Research: 2 (Heinemann et al. 2008)

The patients were selected from different wards of a large regional hospital. They were grouped to be clinical stable, lucid, English speaking and over 18 years of age. There was only one group carrying the same standard specified for the study. For randomisation, data collection forms for each patient were prepared and nurses needed to select randomly the forms containing envelop, where they required recording the readings.

Research: 3 (Jones et al, 1996)

The subjects were volunteers of Emergency Departments such as medical technicians, nurses and physicians without history of hypertension, who were above 18 years of age and not pregnant. The subjects were chosen if they complied with the above criteria. There were about 100 subjects in which 38 were men and 62 were women with age ranging from 18 to 54. This was the sole group selected for the study. The sample was not sufficient for the study which interprets the outcome. The volunteers consist of both hypertensive and normotensive patients. This limited the possibility of assessing the patients with hypotensive nature that might have made it difficult to obtain equivalent results with the two methods.

Research: 4 (Landgraf et al, 2010)

The samples were selected from a cardiac outpatient department. There was no inclusion or exclusion criteria added for choosing subjects. The sample size was around 337; consist of both genders with age range of 22-98 years with different health status. They were not allocated into groups. Procedure was performed in all patients during consultation by using auscultatory/mercury method and automated technique. Discrepancy of readings reported in the study because of different genders and age, especially in old age people.

Research: 5 (Yung et al, 2001)

Subjects were the volunteer participants of a Nursing and Health Sciences department with an age limit of 19-23 years. Blood pressure of each samples were monitored separately in a quiet room on the same day with two automated monitors. The sample of 31 patients was attended by the same detector.

However, the research of Bern et al. (2009) partially fails to accomplish blinding because of circumstances. The possibility of blinding between nurses reflects in the study of Heinemann et al. (2008). The samples were distracted from physical, mental and environmental factors, which might have affected the blood pressure. In an effort to streamline the readings, patients were allowed to rest for a few minutes to ensure proper blood supply to the limbs. These all attempts speculate the characteristics of controlled trial, and would benefit the data collection more appropriate and result analysis flawless.

In all five articles the investigators, who were trained staff, monitored the blood pressure using both automatic and manual methods. Carr (1994) highlighted that, in quantitative studies the close relationship between investigator and subjects usually promotes for enhancing valuable meaningful data, but in these researches samples were restricted to communicate with detector during procedure for ensuring the accuracy of reading. Also, Carr (1994) point out that, in certain quantitative researches the investigators maintains a detached position from clients for focusing more in outcomes, whereas in these types of experimental studies it is not applicable. In randomized control trials all the groups of subjects are dealt with identical manners and conduct same mode of experiments (Sibbald and Roland, 1998).This is clearly visible in two of the randomized studies. Furthermore, time spent for considering each samples and procedure is sufficient.

The data analysis in quantitative studies comprise of creating and determining groups and appraising reliability of each techniques on samples and eventually synthesis the collected data by large organizations (Mantzoukas,2009).This can be seen in comparative study of both Yung and Lau (2001) and Jones et al. (1996). Each study compares the implementation of both methods in the current clinical practice. Statistically significant differences are still noted in the systolic blood pressures with manual and automated method for measuring the blood pressure by the study of Bern et al. (2009). The study was performed by trained seven individuals and carried out at an inpatient medical facility and this gives the opportunity to focus on the outcome more precisely. This study included calculation of bias and precision and displayed results in a graph to measure variations in blood pressure monitoring in automated and manual ways. The literature of Heinemann et al. (2008) partially supports the implementation of manual monitoring of blood pressure as well as partially agreeing with automated monitors. Besides, for randomization, data collection forms for each patient were prepared and nurses needed to select randomly the forms containing envelop, where they required recording the readings.

On the other side, the study of Yung and Lau (2001) declared the accuracy and reliability of automated monitors and recommend its use in healthcare departments with evidence. However, the review of this literature showed some limitations such as lack of controlled comparison, lack of comparison between traditional and automated by different investigators in blind, necessity of relevant population, etc. In addition, the study which was conducted by Jones et al. (1996) completely agreed with manual monitoring of blood pressure. It showcased that, clinical and statistical differences present in two measures of blood pressure. Automated monitoring has higher systolic pressure than manual measurement. This study also contributed that, the blood pressure checking with consistent equipment is essential for providing the real change in patient.

On contrast, the literature of Yung and Lau (2001) there was no significant variation between the readings of two machines and supported the application of automatic blood pressure techniques. However, none of the researches is confident to suggest the application of automated measuring methods alone in the field of healthcare. This literature also constitutes the disadvantages of mercury sphygmomanometer such as probability of mercury leakage from the pressure gauge, fault of control valve and obstructions in the pinhole, which connects mercury column to the pressure of atmosphere. These all defects may contribute false estimation of readings. Critical appraisal of five literature evidence concludes that, the blood pressure measurement taken with automated techniques has difference from traditional cuff method, So that nurses need to consider mercury sphygmomanometer for providing high quality care to patients and to reduce clinical errors.

Discussion
The accurate measurement of arterial blood pressure plays significant role in treating critically ill patients. The findings of five chosen studies compare the accuracy and reliability of two blood pressure monitoring devices such as mercury sphygmomanometer and automatic oscillometric technique. Two studies are strongly support the research question and need for implementing it in to practice instead of following false methods for clinical decision making. Out of this five, two studies partially agreeing the application of manual monitoring in the field of healthcare. The remaining study of Yung and Lau (2001) is against the manual methods of blood pressure monitoring and affirmed in electronic advanced methods. Since, the acute care units are using different types of techniques to measure the blood pressure, the researchers found inaccuracy with machinery system. The results of studies show that traditional monitoring of blood pressure is more accurate than machinery monitoring.

But, few studies failed to show the difference in systolic pressure with both machinery and manual monitoring. The Bland-Altman graphing techniques detected variations in systolic and diastolic BP. It supports the findings of previous studies that conducted by Bur et al. (2000), Coe and Houghton (2002), Davis et al.( 2003) and Parker and Steigerwalt (2004). These studies identified significant difference in systolic and diastolic pressure with two methods of blood pressure monitoring. Also, seems that manual monitoring is more accurate.

However, in intensive care units and other emergency departments still depending machines to gather blood pressure of patients because of its easiness in handling, time saving techniques, reduces the work load of staff, offers continuous monitoring as well as provides alert alarms in case of noted variations in readings. Most of the machines that help to monitor blood pressure also detect other cardinal signs such as pulse rate and respiratory rate. Also, studies support that in neonatal intensive care unit, the use of pulseoxymeter significantly influence the care of neonates. The difficulty to count the pulse rate and blood pressure of small babies can be measured easily with automatic machines. However, the doctors and health care professionals, who seek accurate and precise readings of making clinical decisions regarding interventions, suggest the use of monitoring with sphygmomanometer. When compared to automate machines, it requires certain skills and practice to measure the blood pressure accurately. There are different techniques that usually follow by health practitioners to measure manual blood pressure with sphygmomanometer, according to their knowledge and experience.

Limitations
One of the limitation of this study is the intended strength of samples was not adequate in the study of Heinemann et al (2008). According to the power calculation a sample size of 73 was necessary to evaluate mean arterial blood pressure variation. But among 138 participants, there were only 63 willing subjects. But, the participants are appropriately allocated to intervention and control groups. The patients were selected from different wards of a large regional hospital. They were grouped to be clinical stable, lucid, English speaking and over 18 years of age. There was only one group carrying the same standard specified for the study. The samples were distracted from physical, mental and environmental factors, which might have affected the blood pressure. However, the study remains silent about the accountability of all participants at its conclusion.
Although, the studies were able to confirm the accuracy and reliability of both automated monitors and recommend its use in healthcare departments with evidence. However, there were some limitations such as lack of controlled comparison, lack of comparison between traditional and automated by different investigators in blind, necessity of relevant population etc. It requires advanced researches, which includes calibrations through an assessment by human subject and investigator for obtaining essential information about the validity of automated monitors.

Conclusion
In terse, the studies ensue in a conclusion that traditional method of mercury sphygmomanometer is ineluctable in the nursing scenario, particularly in the event of decision making and/or emergency departments, except one study. However, this exceptional study does not corroborate the idea of implementing the automated technique exclusively in any healthcare facility. The studies articulate the lack of researches conducted in this field and express the demand for imparting extensive cogitation with population, different physical condition, strength of sample, etc. The ordinary prototype in healthcare research is the quantitative approach which generally uses an organized process and methods to gather information under controlled circumstances and accentuates objectivity via statistical analysis. The two quantitative studies in this regard try to adhere to this method. However, the most common case of empirical approach in health care is the controlled clinical trial where strict restraints are exercised over the autonomous and non autonomous variables and randomization of the participants into control and interventional categories. The studies can be considered to show justice to this approach. Hence the studies conclude with a distinct resolution that the traditional manual monitoring of blood pressure method outraces the machinery monitoring with its dependability, accuracy and efficacy.

References

Bern, L., Brandt, M., Mbelu, N., Asonye, U., Fisher, T., Shaver, Y and Serrill, C. (2007) Differences in Blood Pressure Values Obtained with Automated and Manual Methods in Medical Inpatients. Medical and surgical Nursing, 16(6), P.356-360. Bland, J. and Altman, D. (1986) Statistical methods for assessing agreement between two methods of clinical measurement. Lancet, 1, P.7-310.

Bur, A., Hirschl, M., Herkner, H., Oschatz, E., Kofler, J., Woisetschlager, C., et al. (2000) Accuracy of oscillometric blood pressure measurement according to the relation between cuff size and upper-arm circumference in critically ill patients. Critical Care Medicine, 28, P.371-376.

Carr, L. T. (1994) The strengths and weaknesses of quantitative and qualitative research- what method for nursing? Journal of Advanced Nursing, 20(1), P.716-721. Coe, T.R. and Houghton, K. (2002) Comparison of the automated Dinamap blood pressure monitor with the mercury sphygmomanometer for detecting hypertension in the day case pre-assessment clinic. Journal of Ambulatory Surgery, 10, P.9-15.

Day, S.J and Altman, D.G. (2000) Blinding in clinical trials and other studies. British medical journal, 321(7259), P.504.

Davis, J., Davis, I., Bennink, L., Bilello, J., Kaups, K. and Parks, S. N. (2003) Are automated blood pressure measurements accurate in trauma patients? Journal of Trauma, 55, P. 860-863.

Heinemann, M., Sellick, K., Rickard, C., Reynolds, P and McGrail, M. (2008) Automated versus manual blood pressure measurement: A randomized crossover trial .International Journal of Nursing Practice, 14 (4), P. 296-302.

Jones, D., Engelke, M.K., Brown, S.T and Swanson, M. (1996) A comparison of two noninvasively methods of blood pressure measurement in the triage area. Journal of Emergency Nursing, 22(2), P.111-5. Landgraf, J., Wishner, S.H and Kloner, R.A. (2010) Comparison of Automated Oscillometric versus Auscultatory Blood Pressure Measurement. The American Journal of Cardiology, 106(3), P. 386-388.

Sibbald, B. and Roland, M. (1998) Why are randomized controlled trials important? British medical journal, 316(7126), P.201.
Parker, S. and Steigerwalt, S. (2004) The Dinamap dilemma: Inaccuracy of the commonly used Dinamap 8100 compared to simultaneous mercury manometer measurement in hospitalized patients at different levels of blood pressure. American Journal of Hypertension, 17(1), P.S52.

Yung, P.M.B and Lau, B.W.K. (2001) Evaluation of two automatic sphygmomanometers in Hong Kong: Implications for the future development of automated blood pressure monitors in clinical practice. International Journal of Nursing Practice, 7(4), P.246–250.