- Email: [email protected]
Quality of blood pressure measurement in community health centres
+Model
ARTICLE IN PRESS
Enferm Clin. 2017;xxx(xx):xxx---xxx
www.elsevier.es/enfermeriaclinica
ORIGINAL ARTICLE
Quality of blood pressure measurement in community health centres夽 Edgardo Sandoya-Oliveraa,c , Augusto Ferreira-Umpiérrezb,c,∗ , Federico Machado-Gonzáleza,d a
Facultad de Medicina, Instituto Universitario CLAEH, Maldonado, Uruguay Instituto de Bienestar y Salud, Universidad Católica del Uruguay, Montevideo, Uruguay c Facultad de Enfermería y Tecnologías de la Salud, Universidad Católica del Uruguay, Montevideo, Uruguay d Asistencial Médica Departamental de Maldonado, Maldonado, Uruguay b
Received 3 November 2016; accepted 5 February 2017
KEYWORDS Quality of health care; Ambulatory blood pressure monitoring; Hypertension; Primary health care
Abstract Objective: To determine the quality of the blood pressure measurements performed during routine care in community health centres. Method: An observational, cross-sectional study was conducted in 5 private and public health centres in Maldonado, Uruguay, in July---August 2015. The observations were made during the measurements performed by health personnel, using the requirements established by the American Heart Association. An analysis was made on 36 variables that were grouped in categories related to environment, equipment, interrogation, patient, and observer. Statistical analysis was performed using chi-square test or Fisher test. Statistical significance was considered to be less than 5% (p < 0.05). Results: The measurements were made by a registered nurse or nurse in 71% of cases, physician in 20%, and student nurse in 9%. An aneroid sphygmomanometer was used in 89%, and mercury 11%. Satisfactory results were found in variables related to environment (93%), equipment (99%), and patient attitude (82%), and intermediate in the attitudes of the operator (64%), and poor in relation to the interrogation (18%), with the mean of correct variables per measurement being 69%. Conclusions: The main flaws in the procedure were the operator. The measurement of blood pressure is a manoeuvre that healthcare professionals perform thousands of times a year. If the measurement is used for the diagnosis and/or chronic management of arterial hypertension, not systematically applying the established recommendations leads to an inappropriate care of a very significant number of patients. © 2017 Elsevier Espa˜ na, S.L.U. All rights reserved.
夽
Please cite this article as: Sandoya-Olivera E, Ferreira-Umpiérrez A, Machado-González F. Calidad de la medida de la presión arterial en centros de salud comunitarios. Enferm Clin. 2017. http://dx.doi.org/10.1016/j.enfcli.2017.02.001 ∗ Corresponding author. E-mail address: [email protected] (A. Ferreira-Umpiérrez). 2445-1479/© 2017 Elsevier Espa˜ na, S.L.U. All rights reserved.
ENFCLE-647; No. of Pages 9
+Model
ARTICLE IN PRESS
2
E. Sandoya-Olivera et al.
PALABRAS CLAVE Calidad de la atención de salud; Medida de la presión arterial; Hipertensión; Atención Primaria de salud
Calidad de la medida de la presión arterial en centros de salud comunitarios Resumen Objetivo: Conocer la calidad de la medida de la presión arterial realizada en la asistencia habitual en centros de salud comunitarios. Método: Estudio observacional de corte transversal en 5 centros de salud privados y públicos de Maldonado, Uruguay, en julio-agosto de 2015. Se contrastó lo observado durante la medida realizada por personal sanitario con los requisitos establecidos por la American Heart Association. Se analizaron 36 variables que se agruparon en categorías referidas a ambiente, equipamiento, interrogatorio, paciente y observador. Análisis estadístico empleando test de chi2 o test de Fischer. Se consideró significativo el estadístico con valor menor a 5% (p < 0,05). Resultados: Medida realizada por licenciado o enfermero en 71% de los casos, médico en 20% y estudiante de enfermería en 9%. Con esfigmomanómetro aneroide 89% y de mercurio 11%. Se encontraron resultados apropiados en variables referidas a ambiente (93%), equipamiento (99%) y actitudes del paciente (82%), intermedios en las referidas a actitudes del operador (64%) y pobres en las referidas al interrogatorio (18%), siendo 69% el promedio de variables correctas por medida. Conclusiones: Las fallas principales en el procedimiento fueron por parte del operador. La medida de la presión arterial es una maniobra que profesionales sanitarios realizan miles de no. Si la medida está dirigida al diagnóstico y/o manejo crónico de la hipertenveces al a˜ sión arterial, no aplicar de manera sistemática las recomendaciones establecidas conduce a un cuidado inapropiado de un número muy importante de pacientes. © 2017 Elsevier Espa˜ na, S.L.U. Todos los derechos reservados.
What is known? The measurement of blood pressure is a manoeuvre that healthcare professionals perform thousands of times a year, and if the measurement is to have an impact on diagnostic decisions and/or chronic management of arterial hypertension, all recommendations must be systematically applied for accurate measurement to offer patients the best possible healthcare.
What is offered? This study demonstrates the quality of blood pressure measurement and highlights the aspects which are yet to be improved, particularly regarding the primary healthcare professionals who perform the procedure.
Introduction Indirect measurement of blood pressure (BP) was established at the end of the 19th century and is one of the most commonly used clinical procedures today. This is due to the fact that high blood pressure (HBP) is the most prevalent chronic disease1 and two of its complications, coronary heart disease and strokes are the main causes of death2 and disability in Uruguay, similarly to other countries. Precise
measuring of BP is relevant given that the diagnosis of HBP is made from its values and that the normalisation of high figures in people with high blood pressure reduces their risks of stroke and coronary heart disease.3 Although measuring BP is a simple procedure, several factors such as prior repose, environmental characteristics, the presence of pain, tobacco consumption, alcohol consumption of that of other drinks, has an impact on outcome.4 The way in which measurement is made has an impact on recorded figures. Not bearing in mind these aspects leads to obtaining BP values which are different from real ones, which may result in erroneous decisions being made. Overestimation consisting of 5 mmHg of diastolic BP duplicates the number of patients with BP whilst its underestimation of 5 mmHg reduces their number by 62%.5 These errors deprive the patients of treatment which has been demonstrated to be beneficial or, on the contrary, to label someone as having high blood pressure when they do not. Those who are labelled incorrectly as having normal blood pressure will be an undesirable increase in HBP complications. Inversely, those who are supposedly suffering from high blood pressure may experience adverse effects to unnecessary medication and feel anxiety from the knowledge that they are ill and this will lead to an increase in health costs. Outpatient monitoring of BP has proven to be an effective tool for patient diagnosis and follow-up.6 However, it has been perceived that the recommendations regarding patient preparation and measuring technique are rarely followed, and that the equipment used is often imprecise. Research has shown that the usual clinical measurements overestimated BP by 11 mmHg compared with those obtained by a trained nurse and that establishing whether the patient
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres has normal or high BP differed in 42% of cases.5 When the BP figures obtained by an untrained nurse were compared to those of a nurse trained in measuring BP it was found that the former underestimated their value, save in cases of patients with more severe high blood pressure, where there was a tendency to underestimate it.7 In our environment everyday experience shows that often measuring BP is inappropriately performed since due to its accessibility this healthcare procedure tends to be undervalued.8 The objective of this study was to discover the quality of blood pressure measurement carried out by the regular healthcare professions in community health centres.
Methods Study design and participants An observational, cross-sectional study was conducted in private and public community health centres in Maldonado, Uruguay, between July and August 2015. The information was collected by a trained group of university students, supervised by teachers, whilst regular healthcare was carried out, once those who carried out the measurement and those who were subject to the procedure had given their consent. The data collected was contrasted with the requirements for correct measurement of BP, which were defined from the recommendations established by the American Heart Association (AHA).4
Requirements for accurate blood pressure measurement These were defined using variables which were selected by analysing each AHA recommendation and when necessary, review in the original researches they were based on. As a result, 36 variables which represented the factors with relevant impact on BP figures were selected and classified into categories which are presented below.
3
Equipment: sphygmomanometer (certification, calibration, cuff, rubber tubes, functioning of dial, air valves) and stethoscope (state). The team was asked if they had accreditation and if the equipment had been calibrated. We observed whether the cuff and rubber tubes were in good condition and if the dial worked correctly. Questioning: the patient was asked about their intake of coffee, tea, mate, cola soft drinks, if they had smoked during the previous 30 min, if they had an urgent wish to go to the toilet, pain, if they were nervous, if they had previously rested and whether they were anxious about anything at that time. Patient: we observed whether their arm was uncovered and well supported, both feet on the floor, back resting on the back of the chair, comfortable and silent during the procedure. The arm was considered well supported when resting on a surface area which allowed the patient to have their back supported. They were considered to be comfortable when no muscle groups were tense. Observer: seated, appropriate choice of cuff, appropriate adjustment, lower edge ≥2 cm above elbow fold, stethoscope outside cuff, sphygmomanometer at 0 before measuring, speed of deflation 2 mmHg/s, number of measurements and silence. Appropriate size selection was considered when it covered the arm in the correct manner. Adjustment was appropriate when it was firm and there was no empty space within it. A structured data collection record was prepared from the 36 definitive variables, and training was performed for its on-site application, where role play was exercised.
Data collection The area of each institution where the procedure was performed was covered and observation was made whilst the least possible interference was applied. Each variable was recorded as it occurred in order to minimise any possible recording errors. Collected data was recorded on an electronic spreadsheet which was consolidated and analysed.
Data analysis Definition of variables Selecting the variables was made by analysing each AHA recommendation. They were grouped into 5 categories: environment, equipment, questioning, patient and observer. Environment: temperature, humidity, lighting, silence and privacy were assessed. Temperature was considered appropriate if one was comfortable when dressed in light clothing, humidity appropriate if no excess was perceived, lighting appropriate if correct viewing of the sphygmomanometer was possible, silence appropriate if there were no noises which interfered with the procedure and privacy appropriate if there were no people who were not involved in the procedure. We also assessed whether the chair had a back to it and was the right height and if there was a support for the arm. The back was appropriate if the patient could support their back against it, the height was appropriate if the patient could place both feet on the floor and the arm support was suitable if was at right atrium height.
Data analysis was performed from two focal points: from the variables and from the measurements. In the former the outcome of each variable was analysed, verifying whether the fulfilment of the same was appropriate or not. The average of correct variables for each category was also calculated. A compound variable was established (number of appropriate measurements) from the BP value found and the number of measurements made. The chi-square of Fisher test was used for statistical analysis to compare proportions depending on which was appropriate. Statistical significance was considered to be less than 5% (p < 0.05), within a 95% confidence interval and was considered insignificant if it was equal to or above 5%.
Ethical considerations All ethical considerations established in Decree Law No. 379/008 on research with human beings were adhered to,
+Model
ARTICLE IN PRESS
4 and participants were informed of the study objectives, its scope and all aspects relating to their free and informed consent. The study was authorised by the institutional Ethical Committee with reference CAEF/012014.
Results Information was collected on 302 procedures on the BP measurement of 302 patients in 5 health centres (one observation per patient), of which 68% corresponded to the private sector. These were patients from regular healthcare in health centres, the average age of which was 49.7 years (ranging between 18 and 93), and 53% of whom were female. Blood pressure measurement was performed by a registered nurse in 71% of cases, a doctor in 20% and a student nurse in 9% of cases.
Outcome of variables Regarding the environment where measurement was performed, 93% of variables were appropriate, with the outcome of each one listed in Table 1. The sphygmomanometer used was an aneroid one in 89% of cases and a mercury one in 11%. With regards to specific equipment, 99% of the variables were appropriate, and their outcomes are presented in Table 2. Regarding the questioning of the patient, in 18% of cases the variables were appropriate, with the outcome being presented in Table 3. With respect to patient attitudes during the procedure, 82% of the variables were appropriate, and values are listed in Table 4. With respect to the observer’s attitudes during the procedure a, 64% of the variables were appropriate, and results are listed in Table 5.
Results of the measurements Among the 302 measurements performed the range of correct variables was from 19 to 31 (53---86% of the 36 variables analysed), with the average being 25 (69%). Both mean and mode were 25. Table 6 divides the amount of cases into four categories in accordance with the appropriate percentage of variables, for the total of cases and discriminated in accordance to who performed the measurement. Correct variable averages were 26, 25 and 24 per doctor, nurse and student nurse respectively, whilst mode was 24, 25 and 26 respectively. The median for the three groups was 25.
Discussion Many elements may change the measurement of BP. If it has been obtained in an inappropriate manner, its values will not correlate with the target organ damage. This would mean that in most cases, casual readings are inappropriate for the management of patients with HBP. However, BP measurement may also be used in clinical circumstances where precision is not so relevant. In hospitalised or emergency
E. Sandoya-Olivera et al. patients, for example, only the detection of extreme BP values are of interest. On the other hand, the baseline conditions of these patients may be very complex due to pain, anxiety or the severe treatment they are receiving. In general, these values do not serve for diagnostic purposes for HBP or for assessing the degree of control. The diagnosis of HBP requires that several measurements be taken in accordance with correct protocol and separated over time, whilst the prognosis long-term of a hypertensive patient depends on what occurs with their BP during decades of their life and not with the value observed in a specific and exceptional circumstance.8 In contrast, when the outpatient patient is diagnosed with HBP, accurate measurement is essential, since errors in determination may be overestimated and the patient could receive the wrong diagnosis or underestimated leading to a sub diagnosis. One research study compared BP measurement obtained following the guidelines of the AHA and standard healthcare. The former was significantly lower for (−12 mmHg systolic BP and −6 mmHg diastolic, p < 0.05).4 In patients with known HBP measuring with the appropriate technique showed that more patients had BP values in the objective range than when techniques were inappropriate (54% vs 26%, p < 0.05), which illustrates the implications that may occur when measurement guidelines are not followed.4
Environment and measuring equipment A cold environment causes BP to rise, whilst an excessively damp one has the opposite effect. Environmental noise at the place of measurement interferes with correct hearing and is therefore a potential source of error in measurement.9 in our research the variables relating to environment were generally appropriate, with noise that could interfere with the measurement being the trait most removed from appropriateness. Moreover, the chair used was appropriate except in 17% of cases where the place to support the arm was not and the values obtained could have been altered. The correct measurement of BP requires that the arm height be the same as that of the right atrium, because if it is below the values obtained will be higher and if it is above they will be lower. These differences attributable to hydrostatic pressure effects may be ≥10 mmHg, or 2 mmHg every 2 cm above or below heart level.10 Furthermore, if the arm is held by the patient, the isometric effort involved would raise the pressure due to muscular tension.4 We found there were no major problems regarding measuring equipment, although the calibration of the sphygmomanometer was not tested, only externally appreciated. It has frequently been seen that measuring equipment used in medical practices is imprecise, with faults reaching ≥30% for aneroid and mercury devices, and most problems stemming from the cuff, tubes and connectors.11 Much of the equipment used is not certified in the manner established by the health authorities, and it is not known whether measurements are appropriate.12,13 The mercury equipment considered to be the gold standard for measuring, are been replaced due to the risks of contamination from this metal. Aneroid equipment is one of the substitutes, and its
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres Table 1
5
Outcome of the variables referring to environment.
Variable
2 3 7 6 1 5 8 4 Average
Table 2
Appropriate
Ambiance humidity Sufficient lighting for correct viewing Chair height Chair with arm rest Temperature at place of measuring Privacy at place of measuring Support for arm to avoid forced position Absence of background noise during measuring
Table 3
No.
%
No.
%
302 302 302 297 295 273 250 242 280
100 100 100 98 98 90 83 80 93
0 0 0 5 7 29 52 60 22
0 0 0 2 2 10 17 20 7
Outcome of variables referring to measuring equipment.
Variable
9 10 11 14 12 13 Average
Appropriate
Refer to suitable calibration State of hoses State of dial Stethoscope in good condition State of cuff Cuff size in relation to arm
Inappropriate
No.
%
No.
%
302 302 302 302 301 299 301
100 100 100 100 99.7 99 99.7
0 0 0 0 1 3 1
0 0 0 0 0.3 1 0.3
Outcome of variables referring to questioning.
Variable
20 18 15 21 16 19 17 Average
Table 4
Appropriate
Questioned Questioned Questioned Questioned Questioned Questioned Questioned
if had at least 5 min repose if was in pain at that time about consumption of coffee, mate, tea, cola drinks whether anything was worrying them at the time whether they had smoked in the last 30 min whether they were nervous at the time about whether they needed to urinate
Inappropriate
No.
%
No.
%
76 68 57 42 36 34 5 54
25 23 19 14 12 11 8 18
226 234 245 260 266 268 277 248
75 77 81 86 88 89 92 82
Outcome of variables referring to the patient.
Variable
26 25 24 27 23 22 Average
Inappropriate
Appropriate
Comfortable during measuring Seated with both feet resting on the floor Back supported during measuring Not talking during measuring Arm uncovered during measuring Arm correctly supported during measuring
Inappropriate
No.
%
No.
%
281 260 248 247 215 199 246
93 86 82 82 71 66 82
21 42 54 55 87 103 56
7 14 18 18 29 34 18
+Model
ARTICLE IN PRESS
6
E. Sandoya-Olivera et al. Table 5
Outcome of variables referring to observer.
Variable
Appropriate
33 31 29 30 34 36 32 28 35 Average
Sphygmomanometer at 0 mmHg prior to measuring Lower edge of cuff above elbow Observer in silence Cuff adjusted Speed of deflation 2 mmHg/s Appropriate number of measurements Stethoscope placed outside cuff Observer seated Digital preference (rounded to 0)
Table 6
Cases with appropriate measurement according to who took it.
Appropriate variables in measurement 80---89% 70---79% 60---69% 50---59% All
All (n = 302) 7% 21% 69% 3% 100%
Doctor (n = 59) 20% 17% 56% 7% 100%
condition should be verified every two years as it has a greater tendency to lose its calibration.14 In Great Britain it was confirmed that, although in over 80% of cases the BP measurement equipment was in a good state, problems arose with regards to the maintenance and safety of the mercury, and this type of equipment therefore ceased to be used.15 A common problem of the sphygmomanometer is that in the majority of cases a standard sized device is used to measure BP in patients with large arms, and diastolic BP was therefore overestimated. This was only observed in 1% of cases in our study.
Measuring technique The main problems confirmed in our study were related to measuring technique, with the primary fault lying with the questions the patient were asked, where only 18% of variables were appropriate. A similar finding was confirmed in a research study conducted in 14 Italian hospitals although the magnitude of the problem there was lower.10 In this regard, caffeine intake and similar products may increase BP and not questioning the patient may therefore lead to error.4 However, recent research has raised doubts about this, since it showed no differences in BP in young people one hour after they had drunk coffee.16 In our study only in a quarter of cases was the patient questioned as to whether they had had at least 5 min rest previously. In fewer cases they were asked if they were in pain at the time of measuring and on very few accounts were they asked if they felt anxious or had an urgent need to urinate. Ignoring these aspects may lead to overestimation of BP figures, since these circumstances are associated with a state of alert which temporarily raises the figures.4
Inappropriate
No.
%
No.
%
300 297 261 259 227 202 105 66 0 192
99 97 86 86 75 67 35 22 0 64
2 5 41 43 75 101 197 234 302 110
0.6 3 14 14 25 33 65 78 100 36
Nurse (n = 214) 4% 31% 64% 1% 100%
Student nurse (n = 29) 0% 45% 45% 10% 100%
p <0.05 <0.05 DK <0.05 ---
Patient attitudes during measurement were appropriate in relation to 82% of variables, with the most common problem being the arm not being supported appropriately (34%). This had an impact on BP measurement, as it has been confirmed that in normal blood pressure lowering the arm increased the BP by 8 mmHg compared with the correct measurement and in hypertensive people this was 23 mmHg (p < 0.05).17 In 29% of cases the arm where BP was measured was not uncovered, which is inappropriate since thick clothing will modify the diameter of the arm and because placing a stethoscope over clothing will lead to insufficient audition. During measurement it is necessary for the patient to have both feet on the ground. Crossing of the legs increases systolic BP up to 8 mmHg. Muscle tension generated also raises diastolic BP levels by 6 mmHg.18 One error which occurred in all cases of the observer was the rounding up to 0 of the measurement (digital preference). Terminal digital preference is one of the most frequent traits of a suboptimal measurement. It is recommended that the observer measure BP to the nearest 2 mmHg. The error of digital preference is practically the norm in our environment and there is no awareness of it. If we consider that BP values are distributed randomly, if the equipment records values with a 2 mmHg precision, it is to be expected that 20% of recorded values end in 0, whilst another 20% end in 2, 4, 6 and 8. Research into 28,841 pregnant women, found that in 78% of cases the measurement was rounded at 0 (the other 22% did end in 0), which reduced the prevalence of HBP from 26% to 13% in the total sample and from 43% to 25% in high risk pregnant women.19 In another research study it was confirmed that in 99% of cases the systolic and diastolic BP measured by the nurse ended in 0, with a difference of >5 mmHg between this value
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres and that obtained using digital equipment being confirmed in 60% of cases. This meant that in general the nurses overestimated the BP except in patients with severe hypertension where it was subestimated.7 Preference for digital equipment also arose from comparing previous research data, one of which was conducted from regular healthcare data in check-ups.20 The second most common fault (65% of cases) was placing the stethoscope under the cuff, which interferes with correct audition and may lead to error.4 The observer error is a greater problem in the auscultatory method but systematic errors lead to intra and interobserver mistakes. In 25 cases the speed of BP deflation was above 2 mmHg/s, which is inappropriate. A deflation speed of >2 mmHg/s may lead to underestimation of systolic and overestimation of diastolic values, with the use of a speed of 2---3 mmHg/s in the cases in which heart beat is very low.21 The predictive value of a high number of measurements is greater than that of a single measurement in the surgery.21 Although it is recommended that under all circumstances at least two measurements of BP be made at intervals of under 1 min and that if there is a difference >5 mmHg between both a third should be done and the value averaged, this recommendation has no solid evidence to sustain it.22 In our research we considered it appropriate for a single measurement to be made when the value obtained was normal, but inappropriate when the BP was ≥140/90 mmHg, when the undertaking of 2 or more determinations was considered appropriate. In clinical practice this is highly important, since usually successive measurements have lower BP values and they are finally closest to those of the baseline situation. When the BP measurement is undertaken with a mercury device it is important for the observer to be seated so that their spine is at eye height and no parallax errors are committed.
Quality of the measurements When the quality of each of the 302 measurements performed was assessed, it was confirmed that in no cases was a totally correct technique employed, and only in 7% of cases were ≥80% of the variables appropriate. 90% of measurements had between 60% and 79% correct variables, which highlight the problem. When the quality of measurements was analysed by the different observers, a higher proportion of doctors with records in the upper quartile of those analysed was observed, in addition to more nurses in the second quartile and more student nurses in the bottom quartile (p < 0.05). This reality coincides with studies which have shown that only a minority of professionals have adhered to some of the recommendations of the AHA to measure BP, such as a research in Japan, conducted with primary care doctors, which analysed the performing of the measurement through 20 items, showing that only 8 of them were fulfilled in regular practice.23 The magnitude of the problem caused by imprecise measuring of BP may be calculated by considering the effects of a small but persistent error in measurement, since a few mmHgs of systematic error have a considerable impact on
7
each case, leading to over diagnosis, under diagnosis, or incorrect classification of HBP control. Studies have exposed the magnitude of the impact of systematic error in measuring by showing that undetectable differences when rounded up to 0 may increase or decreases HBP in over 50% and in over 40% in HBP control.5,24 Evidence has shown that reducing diastolic measurements by only 5 mmHg for 5 years reduces the relative risk of stroke by 42%, and therefore not measuring BP precisely may mean losing detection of a very favourable progress on the health of the hypertensive patient.25 The findings from this study are relevant for healthcare practice, although several limitations should be taken into account when analysing outcome. Firstly, the study was conducted by direct observation during the BP measuring procedure, which introduces an observation bias (Hawthorne effect).26 this was evident from the fact that during the first measurements the staff adopted a meticulous approach, which was gradually abandoned in successive measurements. Furthermore, the equipment was not objectively assessed with regards to calibration, and this limited the value of the reported BP results. Our findings confirm the suggested hypothesis that the quality of measurement in standard clinical practice is mostly inappropriate, and requires correction. Given that BP levels are the main factor for deciding whether to start or adjust hypertension treatment, this measurement is extremely relevant. Only the readings obtained with the recommended technique are appropriate for taking decision and predicting long-term cardiovascular risk. One possibility for improvement consists in using semi-automatic electronic equipment validated according to some of the accepted protocols.27,28 The use of these has the advantage of eliminating several of the errors committed by the observer, such as the terminal digital preference, inappropriate speed of deflation, inappropriate placement of stethoscope, errors relating to auditory problems and those relating to the difference of height between the eyes of the observer and the mercury column. Their use in standard assistance would have these advantages, although their potential limitations would have to be present such as the use of a single cuff for different arm diameters, imprecision of measurement in patients with atrial fibrillation and a percentage of varying unreliable measurements. To conclude, the main shortcomings in the procedure were made by the operator. Measuring blood pressure is a manoeuvre carried out by health professionals thousands of times per year. If the measurements are aimed at diagnosis and/or chronic management of hypertension, nonsystematic application of the established recommendations may lead to inappropriate care in a very high number of patients. It is therefore necessary to communicate to the patients the importance of a correct procedure when their BP is being measured at home or in other environments so that they bear this in mind.
Conflict of interests The authors have no conflict of interests to declare.
+Model
ARTICLE IN PRESS
8
Acknowledgements Our thanks to the healthcare professionals and patients involved in measuring blood pressure for allowing us to observe the procedure whilst it was ongoing. Also to the authorities of the Intendencia Departamental de Maldonado, RAP-ASSE, CRAME (SEMM-Mautone) and Asistencial Médica Departamental de Maldonado for allowing us to conduct this research study in their facilities. Also to the collaborators: Br. Ana Patricia Nogueira, Br. Leticia Olivera, Br. María Emilia Lasa, Br. Sara dos Santos, Br. Lucía Nadruz, Br. Santiago Cal, Br. Micaela Orihuela, Br. Santiago Sánchez.
References 1. Sandoya E, Puppo T, Vázquez H, Portos A, Castro M, Fort Z. Evolución de la hipertensión arterial en Uruguay: 1948-2011. Rev Urug Cardiol. 2012;27:377---86. 2. Comisión Honoraria para la Salud Cardiovascular del Uruguay. Mortalidad por enfermedades cardiovasculares en Uruguay 2012; 2013. Available from: http:// www.cardiosalud.org/files/documents/libro mortalidad 2012.pdf [accessed 10.06.16]. 3. James PA, Oparil S, Carter BL, Cushman WC, DennisonHimmelfarb C, Handler J, et al. 2014 Evidence-based Guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311:507---20. 4. Pickering T, Hall J, Appel L, Falkner B, Graves J, Hill M, et al. Recommendations for blood pressure measurement in humans and experimental animals. Part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research. Hypertension. 2005;45:142---6. 5. Campbell NR, Culleton BW, McKay DW. Misclassification of blood pressure by usual measurement in ambulatory physician practices. Am J Hypertens. 2005;18:1522---7. 6. Garzón-Qui˜ nones M, Gallardo-Gonzalo C, Padín-Minaya C, López-Pisa RM, Rodríguez-Latre LM. Descriptive study of ambulatory blood pressure monitoring in the Primary Care Nursing clinic. Enferm Clín. 2013;23:218---24. 7. Roubsanthisuk W, Wongsurin U, Saravich S, Buranakitjaroen P. Blood pressure determination by traditionally trained personnel is less reliable and tends to underestimate the severity of moderate to severe hypertension. Blood Press Monit. 2007;12:61---8. 8. Sandoya E. Los 10 errores más frecuentes en el manejo de la hipertensión arterial. Tend Med. 2013;21:25---31. 9. Burgess SE, MacLaughlin EJ, Smith PA, Salcido A, Benton TJ. Blood pressure rising: differences between current clinical and recommended measurement techniques. J Am Soc Hypertens. 2011;5:484---8. 10. Netea RT, Lenders JW, Smits P, Thien T. Arm position is important for blood pressure measurement. J Hum Hypertens. 1999;13:105---9.
E. Sandoya-Olivera et al. 11. Amoore JN, Guehenec M, Scordecchia R, Scott DH. Auditing the technology used to measure blood pressure. J Med Eng Technol. 2010;34:209---16. 12. Ministerio de Salud Pública. Decreto 520/996 referente a esfigmomanómetros de mercurio. Available from: www.msp.gub.uy/andocasociado.aspx?180,15276 [accessed 16.06.16]. 13. Ministerio de Industria, Energía y Minería. Reglamento técnico de esfigmomanómetros electrónicos; 2011. Available from: http://archivo.presidencia.gub. uy/sci/decretos/2011/01/miem 396.pdf [accessed 16.06.16]. 14. Yarows SA, Qian K. Accuracy of aneroid sphygmomanometers in clinical usage: University of Michigan experience. Blood Press Monit. 2001;6:101---6. 15. McVicker JT. Blood pressure measurement --- does anyone do it right? An assessment of the reliability of equipment in use and the measurement techniques of clinicians. J Fam Plan Reprod Health Care. 2001;27:163---4. 16. Teng CL, Lim WY, Chua CZ, Teo RS, Lin KT, Yeo JC. Does a single cup of caffeinated drink significantly increase blood pressure in young adults? A randomised controlled trial. Aust Fam Physician. 2016;45:65---8. 17. Mourad A, Carney S, Gillies A, Jones B, Nanra R, Trevillian P. Arm position and blood pressure: a risk factor for hypertension. J Hum Hypertens. 2003;17:389---95. 18. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Böhm M, et al. 2013 ESH/ESC guidelines for the management of arterial hypertension. Eur Heart J. 2013;34:2159---219. 19. Wen SH, Kramer MS, Joey J, Hanley JA, Usher RH. Terminal digit preference, random error and bias in routine clinical measurement of blood pressure. J Clin Epidemiol. 1993;46:1187---93. 20. Fort Z, Portos A, Castro M, Pi˜ neyro C, Ciganda C, Bermúdez Y, et al. Factores de riesgo cardiovascular en 74.420 solicitantes de carne de salud. Rev Urug Cardiol. 2012;27:150---61. 21. Wingfield D, Freeman GK, Bulpitt CJ, Gerneral Practice Hypertension Study Group (GPHSG). Selective recording in blood pressure readings may increase subsequent mortality. QJM. 2002;95:571---7. 22. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Böhm M, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension. The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). J Hypertens. 2013;31: 1281---357. 23. Asai Y, Kawamoto R, Nago N, Kajii E. Blood pressure measurement by primary care physicians: comparison with the standard method. Nihon Koshu Eisei Zasshi. 2000;47:326---36. 24. Turner MJ, Baker AB, Kam PC. Effects of systematic errors in blood pressure measurements on the diagnosis of hypertension. Blood Press Monit. 2004;9: 249---53. 25. Collins R, Peto R, MacMahon S, Hebert P, Fiebach NH, Eberlein KA, et al. Blood pressure, stroke, and coronary heart disease. Part 2, short-term reductlons in blood pressure: overview of randomised drug trials in their epidemlological context. Lancet. 1990;335:827---38.
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres 26. McCarney R, Warner J, Iliffe S, van Haselen R, Griffin M, Fisher P. The Hawthorne effect: a randomised, controlled trial. BMC Med Res Methodol. 2007;7:30. 27. O’Brien E, Atkins N, Stergiou G, Karpettas N, Parati G, Asmar R, et al. Working Group on Blood Pressure Monitoring of the European Society of Hypertension European Society of Hypertension International Protocol revision
9
2010 for the validation of blood pressure measuring devices in adults. Blood Press Monit. 2010;15:23---38. 28. Association for the Advancement of Medical Instrumentation. Manual, electronic or automated sphygmomanometers. AAMI/CDV-1 SP10. Arlington, VA: Association for the Advancement of Medical Instrumentation; 2002.
ARTICLE IN PRESS
Enferm Clin. 2017;xxx(xx):xxx---xxx
www.elsevier.es/enfermeriaclinica
ORIGINAL ARTICLE
Quality of blood pressure measurement in community health centres夽 Edgardo Sandoya-Oliveraa,c , Augusto Ferreira-Umpiérrezb,c,∗ , Federico Machado-Gonzáleza,d a
Facultad de Medicina, Instituto Universitario CLAEH, Maldonado, Uruguay Instituto de Bienestar y Salud, Universidad Católica del Uruguay, Montevideo, Uruguay c Facultad de Enfermería y Tecnologías de la Salud, Universidad Católica del Uruguay, Montevideo, Uruguay d Asistencial Médica Departamental de Maldonado, Maldonado, Uruguay b
Received 3 November 2016; accepted 5 February 2017
KEYWORDS Quality of health care; Ambulatory blood pressure monitoring; Hypertension; Primary health care
Abstract Objective: To determine the quality of the blood pressure measurements performed during routine care in community health centres. Method: An observational, cross-sectional study was conducted in 5 private and public health centres in Maldonado, Uruguay, in July---August 2015. The observations were made during the measurements performed by health personnel, using the requirements established by the American Heart Association. An analysis was made on 36 variables that were grouped in categories related to environment, equipment, interrogation, patient, and observer. Statistical analysis was performed using chi-square test or Fisher test. Statistical significance was considered to be less than 5% (p < 0.05). Results: The measurements were made by a registered nurse or nurse in 71% of cases, physician in 20%, and student nurse in 9%. An aneroid sphygmomanometer was used in 89%, and mercury 11%. Satisfactory results were found in variables related to environment (93%), equipment (99%), and patient attitude (82%), and intermediate in the attitudes of the operator (64%), and poor in relation to the interrogation (18%), with the mean of correct variables per measurement being 69%. Conclusions: The main flaws in the procedure were the operator. The measurement of blood pressure is a manoeuvre that healthcare professionals perform thousands of times a year. If the measurement is used for the diagnosis and/or chronic management of arterial hypertension, not systematically applying the established recommendations leads to an inappropriate care of a very significant number of patients. © 2017 Elsevier Espa˜ na, S.L.U. All rights reserved.
夽
Please cite this article as: Sandoya-Olivera E, Ferreira-Umpiérrez A, Machado-González F. Calidad de la medida de la presión arterial en centros de salud comunitarios. Enferm Clin. 2017. http://dx.doi.org/10.1016/j.enfcli.2017.02.001 ∗ Corresponding author. E-mail address: [email protected] (A. Ferreira-Umpiérrez). 2445-1479/© 2017 Elsevier Espa˜ na, S.L.U. All rights reserved.
ENFCLE-647; No. of Pages 9
+Model
ARTICLE IN PRESS
2
E. Sandoya-Olivera et al.
PALABRAS CLAVE Calidad de la atención de salud; Medida de la presión arterial; Hipertensión; Atención Primaria de salud
Calidad de la medida de la presión arterial en centros de salud comunitarios Resumen Objetivo: Conocer la calidad de la medida de la presión arterial realizada en la asistencia habitual en centros de salud comunitarios. Método: Estudio observacional de corte transversal en 5 centros de salud privados y públicos de Maldonado, Uruguay, en julio-agosto de 2015. Se contrastó lo observado durante la medida realizada por personal sanitario con los requisitos establecidos por la American Heart Association. Se analizaron 36 variables que se agruparon en categorías referidas a ambiente, equipamiento, interrogatorio, paciente y observador. Análisis estadístico empleando test de chi2 o test de Fischer. Se consideró significativo el estadístico con valor menor a 5% (p < 0,05). Resultados: Medida realizada por licenciado o enfermero en 71% de los casos, médico en 20% y estudiante de enfermería en 9%. Con esfigmomanómetro aneroide 89% y de mercurio 11%. Se encontraron resultados apropiados en variables referidas a ambiente (93%), equipamiento (99%) y actitudes del paciente (82%), intermedios en las referidas a actitudes del operador (64%) y pobres en las referidas al interrogatorio (18%), siendo 69% el promedio de variables correctas por medida. Conclusiones: Las fallas principales en el procedimiento fueron por parte del operador. La medida de la presión arterial es una maniobra que profesionales sanitarios realizan miles de no. Si la medida está dirigida al diagnóstico y/o manejo crónico de la hipertenveces al a˜ sión arterial, no aplicar de manera sistemática las recomendaciones establecidas conduce a un cuidado inapropiado de un número muy importante de pacientes. © 2017 Elsevier Espa˜ na, S.L.U. Todos los derechos reservados.
What is known? The measurement of blood pressure is a manoeuvre that healthcare professionals perform thousands of times a year, and if the measurement is to have an impact on diagnostic decisions and/or chronic management of arterial hypertension, all recommendations must be systematically applied for accurate measurement to offer patients the best possible healthcare.
What is offered? This study demonstrates the quality of blood pressure measurement and highlights the aspects which are yet to be improved, particularly regarding the primary healthcare professionals who perform the procedure.
Introduction Indirect measurement of blood pressure (BP) was established at the end of the 19th century and is one of the most commonly used clinical procedures today. This is due to the fact that high blood pressure (HBP) is the most prevalent chronic disease1 and two of its complications, coronary heart disease and strokes are the main causes of death2 and disability in Uruguay, similarly to other countries. Precise
measuring of BP is relevant given that the diagnosis of HBP is made from its values and that the normalisation of high figures in people with high blood pressure reduces their risks of stroke and coronary heart disease.3 Although measuring BP is a simple procedure, several factors such as prior repose, environmental characteristics, the presence of pain, tobacco consumption, alcohol consumption of that of other drinks, has an impact on outcome.4 The way in which measurement is made has an impact on recorded figures. Not bearing in mind these aspects leads to obtaining BP values which are different from real ones, which may result in erroneous decisions being made. Overestimation consisting of 5 mmHg of diastolic BP duplicates the number of patients with BP whilst its underestimation of 5 mmHg reduces their number by 62%.5 These errors deprive the patients of treatment which has been demonstrated to be beneficial or, on the contrary, to label someone as having high blood pressure when they do not. Those who are labelled incorrectly as having normal blood pressure will be an undesirable increase in HBP complications. Inversely, those who are supposedly suffering from high blood pressure may experience adverse effects to unnecessary medication and feel anxiety from the knowledge that they are ill and this will lead to an increase in health costs. Outpatient monitoring of BP has proven to be an effective tool for patient diagnosis and follow-up.6 However, it has been perceived that the recommendations regarding patient preparation and measuring technique are rarely followed, and that the equipment used is often imprecise. Research has shown that the usual clinical measurements overestimated BP by 11 mmHg compared with those obtained by a trained nurse and that establishing whether the patient
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres has normal or high BP differed in 42% of cases.5 When the BP figures obtained by an untrained nurse were compared to those of a nurse trained in measuring BP it was found that the former underestimated their value, save in cases of patients with more severe high blood pressure, where there was a tendency to underestimate it.7 In our environment everyday experience shows that often measuring BP is inappropriately performed since due to its accessibility this healthcare procedure tends to be undervalued.8 The objective of this study was to discover the quality of blood pressure measurement carried out by the regular healthcare professions in community health centres.
Methods Study design and participants An observational, cross-sectional study was conducted in private and public community health centres in Maldonado, Uruguay, between July and August 2015. The information was collected by a trained group of university students, supervised by teachers, whilst regular healthcare was carried out, once those who carried out the measurement and those who were subject to the procedure had given their consent. The data collected was contrasted with the requirements for correct measurement of BP, which were defined from the recommendations established by the American Heart Association (AHA).4
Requirements for accurate blood pressure measurement These were defined using variables which were selected by analysing each AHA recommendation and when necessary, review in the original researches they were based on. As a result, 36 variables which represented the factors with relevant impact on BP figures were selected and classified into categories which are presented below.
3
Equipment: sphygmomanometer (certification, calibration, cuff, rubber tubes, functioning of dial, air valves) and stethoscope (state). The team was asked if they had accreditation and if the equipment had been calibrated. We observed whether the cuff and rubber tubes were in good condition and if the dial worked correctly. Questioning: the patient was asked about their intake of coffee, tea, mate, cola soft drinks, if they had smoked during the previous 30 min, if they had an urgent wish to go to the toilet, pain, if they were nervous, if they had previously rested and whether they were anxious about anything at that time. Patient: we observed whether their arm was uncovered and well supported, both feet on the floor, back resting on the back of the chair, comfortable and silent during the procedure. The arm was considered well supported when resting on a surface area which allowed the patient to have their back supported. They were considered to be comfortable when no muscle groups were tense. Observer: seated, appropriate choice of cuff, appropriate adjustment, lower edge ≥2 cm above elbow fold, stethoscope outside cuff, sphygmomanometer at 0 before measuring, speed of deflation 2 mmHg/s, number of measurements and silence. Appropriate size selection was considered when it covered the arm in the correct manner. Adjustment was appropriate when it was firm and there was no empty space within it. A structured data collection record was prepared from the 36 definitive variables, and training was performed for its on-site application, where role play was exercised.
Data collection The area of each institution where the procedure was performed was covered and observation was made whilst the least possible interference was applied. Each variable was recorded as it occurred in order to minimise any possible recording errors. Collected data was recorded on an electronic spreadsheet which was consolidated and analysed.
Data analysis Definition of variables Selecting the variables was made by analysing each AHA recommendation. They were grouped into 5 categories: environment, equipment, questioning, patient and observer. Environment: temperature, humidity, lighting, silence and privacy were assessed. Temperature was considered appropriate if one was comfortable when dressed in light clothing, humidity appropriate if no excess was perceived, lighting appropriate if correct viewing of the sphygmomanometer was possible, silence appropriate if there were no noises which interfered with the procedure and privacy appropriate if there were no people who were not involved in the procedure. We also assessed whether the chair had a back to it and was the right height and if there was a support for the arm. The back was appropriate if the patient could support their back against it, the height was appropriate if the patient could place both feet on the floor and the arm support was suitable if was at right atrium height.
Data analysis was performed from two focal points: from the variables and from the measurements. In the former the outcome of each variable was analysed, verifying whether the fulfilment of the same was appropriate or not. The average of correct variables for each category was also calculated. A compound variable was established (number of appropriate measurements) from the BP value found and the number of measurements made. The chi-square of Fisher test was used for statistical analysis to compare proportions depending on which was appropriate. Statistical significance was considered to be less than 5% (p < 0.05), within a 95% confidence interval and was considered insignificant if it was equal to or above 5%.
Ethical considerations All ethical considerations established in Decree Law No. 379/008 on research with human beings were adhered to,
+Model
ARTICLE IN PRESS
4 and participants were informed of the study objectives, its scope and all aspects relating to their free and informed consent. The study was authorised by the institutional Ethical Committee with reference CAEF/012014.
Results Information was collected on 302 procedures on the BP measurement of 302 patients in 5 health centres (one observation per patient), of which 68% corresponded to the private sector. These were patients from regular healthcare in health centres, the average age of which was 49.7 years (ranging between 18 and 93), and 53% of whom were female. Blood pressure measurement was performed by a registered nurse in 71% of cases, a doctor in 20% and a student nurse in 9% of cases.
Outcome of variables Regarding the environment where measurement was performed, 93% of variables were appropriate, with the outcome of each one listed in Table 1. The sphygmomanometer used was an aneroid one in 89% of cases and a mercury one in 11%. With regards to specific equipment, 99% of the variables were appropriate, and their outcomes are presented in Table 2. Regarding the questioning of the patient, in 18% of cases the variables were appropriate, with the outcome being presented in Table 3. With respect to patient attitudes during the procedure, 82% of the variables were appropriate, and values are listed in Table 4. With respect to the observer’s attitudes during the procedure a, 64% of the variables were appropriate, and results are listed in Table 5.
Results of the measurements Among the 302 measurements performed the range of correct variables was from 19 to 31 (53---86% of the 36 variables analysed), with the average being 25 (69%). Both mean and mode were 25. Table 6 divides the amount of cases into four categories in accordance with the appropriate percentage of variables, for the total of cases and discriminated in accordance to who performed the measurement. Correct variable averages were 26, 25 and 24 per doctor, nurse and student nurse respectively, whilst mode was 24, 25 and 26 respectively. The median for the three groups was 25.
Discussion Many elements may change the measurement of BP. If it has been obtained in an inappropriate manner, its values will not correlate with the target organ damage. This would mean that in most cases, casual readings are inappropriate for the management of patients with HBP. However, BP measurement may also be used in clinical circumstances where precision is not so relevant. In hospitalised or emergency
E. Sandoya-Olivera et al. patients, for example, only the detection of extreme BP values are of interest. On the other hand, the baseline conditions of these patients may be very complex due to pain, anxiety or the severe treatment they are receiving. In general, these values do not serve for diagnostic purposes for HBP or for assessing the degree of control. The diagnosis of HBP requires that several measurements be taken in accordance with correct protocol and separated over time, whilst the prognosis long-term of a hypertensive patient depends on what occurs with their BP during decades of their life and not with the value observed in a specific and exceptional circumstance.8 In contrast, when the outpatient patient is diagnosed with HBP, accurate measurement is essential, since errors in determination may be overestimated and the patient could receive the wrong diagnosis or underestimated leading to a sub diagnosis. One research study compared BP measurement obtained following the guidelines of the AHA and standard healthcare. The former was significantly lower for (−12 mmHg systolic BP and −6 mmHg diastolic, p < 0.05).4 In patients with known HBP measuring with the appropriate technique showed that more patients had BP values in the objective range than when techniques were inappropriate (54% vs 26%, p < 0.05), which illustrates the implications that may occur when measurement guidelines are not followed.4
Environment and measuring equipment A cold environment causes BP to rise, whilst an excessively damp one has the opposite effect. Environmental noise at the place of measurement interferes with correct hearing and is therefore a potential source of error in measurement.9 in our research the variables relating to environment were generally appropriate, with noise that could interfere with the measurement being the trait most removed from appropriateness. Moreover, the chair used was appropriate except in 17% of cases where the place to support the arm was not and the values obtained could have been altered. The correct measurement of BP requires that the arm height be the same as that of the right atrium, because if it is below the values obtained will be higher and if it is above they will be lower. These differences attributable to hydrostatic pressure effects may be ≥10 mmHg, or 2 mmHg every 2 cm above or below heart level.10 Furthermore, if the arm is held by the patient, the isometric effort involved would raise the pressure due to muscular tension.4 We found there were no major problems regarding measuring equipment, although the calibration of the sphygmomanometer was not tested, only externally appreciated. It has frequently been seen that measuring equipment used in medical practices is imprecise, with faults reaching ≥30% for aneroid and mercury devices, and most problems stemming from the cuff, tubes and connectors.11 Much of the equipment used is not certified in the manner established by the health authorities, and it is not known whether measurements are appropriate.12,13 The mercury equipment considered to be the gold standard for measuring, are been replaced due to the risks of contamination from this metal. Aneroid equipment is one of the substitutes, and its
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres Table 1
5
Outcome of the variables referring to environment.
Variable
2 3 7 6 1 5 8 4 Average
Table 2
Appropriate
Ambiance humidity Sufficient lighting for correct viewing Chair height Chair with arm rest Temperature at place of measuring Privacy at place of measuring Support for arm to avoid forced position Absence of background noise during measuring
Table 3
No.
%
No.
%
302 302 302 297 295 273 250 242 280
100 100 100 98 98 90 83 80 93
0 0 0 5 7 29 52 60 22
0 0 0 2 2 10 17 20 7
Outcome of variables referring to measuring equipment.
Variable
9 10 11 14 12 13 Average
Appropriate
Refer to suitable calibration State of hoses State of dial Stethoscope in good condition State of cuff Cuff size in relation to arm
Inappropriate
No.
%
No.
%
302 302 302 302 301 299 301
100 100 100 100 99.7 99 99.7
0 0 0 0 1 3 1
0 0 0 0 0.3 1 0.3
Outcome of variables referring to questioning.
Variable
20 18 15 21 16 19 17 Average
Table 4
Appropriate
Questioned Questioned Questioned Questioned Questioned Questioned Questioned
if had at least 5 min repose if was in pain at that time about consumption of coffee, mate, tea, cola drinks whether anything was worrying them at the time whether they had smoked in the last 30 min whether they were nervous at the time about whether they needed to urinate
Inappropriate
No.
%
No.
%
76 68 57 42 36 34 5 54
25 23 19 14 12 11 8 18
226 234 245 260 266 268 277 248
75 77 81 86 88 89 92 82
Outcome of variables referring to the patient.
Variable
26 25 24 27 23 22 Average
Inappropriate
Appropriate
Comfortable during measuring Seated with both feet resting on the floor Back supported during measuring Not talking during measuring Arm uncovered during measuring Arm correctly supported during measuring
Inappropriate
No.
%
No.
%
281 260 248 247 215 199 246
93 86 82 82 71 66 82
21 42 54 55 87 103 56
7 14 18 18 29 34 18
+Model
ARTICLE IN PRESS
6
E. Sandoya-Olivera et al. Table 5
Outcome of variables referring to observer.
Variable
Appropriate
33 31 29 30 34 36 32 28 35 Average
Sphygmomanometer at 0 mmHg prior to measuring Lower edge of cuff above elbow Observer in silence Cuff adjusted Speed of deflation 2 mmHg/s Appropriate number of measurements Stethoscope placed outside cuff Observer seated Digital preference (rounded to 0)
Table 6
Cases with appropriate measurement according to who took it.
Appropriate variables in measurement 80---89% 70---79% 60---69% 50---59% All
All (n = 302) 7% 21% 69% 3% 100%
Doctor (n = 59) 20% 17% 56% 7% 100%
condition should be verified every two years as it has a greater tendency to lose its calibration.14 In Great Britain it was confirmed that, although in over 80% of cases the BP measurement equipment was in a good state, problems arose with regards to the maintenance and safety of the mercury, and this type of equipment therefore ceased to be used.15 A common problem of the sphygmomanometer is that in the majority of cases a standard sized device is used to measure BP in patients with large arms, and diastolic BP was therefore overestimated. This was only observed in 1% of cases in our study.
Measuring technique The main problems confirmed in our study were related to measuring technique, with the primary fault lying with the questions the patient were asked, where only 18% of variables were appropriate. A similar finding was confirmed in a research study conducted in 14 Italian hospitals although the magnitude of the problem there was lower.10 In this regard, caffeine intake and similar products may increase BP and not questioning the patient may therefore lead to error.4 However, recent research has raised doubts about this, since it showed no differences in BP in young people one hour after they had drunk coffee.16 In our study only in a quarter of cases was the patient questioned as to whether they had had at least 5 min rest previously. In fewer cases they were asked if they were in pain at the time of measuring and on very few accounts were they asked if they felt anxious or had an urgent need to urinate. Ignoring these aspects may lead to overestimation of BP figures, since these circumstances are associated with a state of alert which temporarily raises the figures.4
Inappropriate
No.
%
No.
%
300 297 261 259 227 202 105 66 0 192
99 97 86 86 75 67 35 22 0 64
2 5 41 43 75 101 197 234 302 110
0.6 3 14 14 25 33 65 78 100 36
Nurse (n = 214) 4% 31% 64% 1% 100%
Student nurse (n = 29) 0% 45% 45% 10% 100%
p <0.05 <0.05 DK <0.05 ---
Patient attitudes during measurement were appropriate in relation to 82% of variables, with the most common problem being the arm not being supported appropriately (34%). This had an impact on BP measurement, as it has been confirmed that in normal blood pressure lowering the arm increased the BP by 8 mmHg compared with the correct measurement and in hypertensive people this was 23 mmHg (p < 0.05).17 In 29% of cases the arm where BP was measured was not uncovered, which is inappropriate since thick clothing will modify the diameter of the arm and because placing a stethoscope over clothing will lead to insufficient audition. During measurement it is necessary for the patient to have both feet on the ground. Crossing of the legs increases systolic BP up to 8 mmHg. Muscle tension generated also raises diastolic BP levels by 6 mmHg.18 One error which occurred in all cases of the observer was the rounding up to 0 of the measurement (digital preference). Terminal digital preference is one of the most frequent traits of a suboptimal measurement. It is recommended that the observer measure BP to the nearest 2 mmHg. The error of digital preference is practically the norm in our environment and there is no awareness of it. If we consider that BP values are distributed randomly, if the equipment records values with a 2 mmHg precision, it is to be expected that 20% of recorded values end in 0, whilst another 20% end in 2, 4, 6 and 8. Research into 28,841 pregnant women, found that in 78% of cases the measurement was rounded at 0 (the other 22% did end in 0), which reduced the prevalence of HBP from 26% to 13% in the total sample and from 43% to 25% in high risk pregnant women.19 In another research study it was confirmed that in 99% of cases the systolic and diastolic BP measured by the nurse ended in 0, with a difference of >5 mmHg between this value
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres and that obtained using digital equipment being confirmed in 60% of cases. This meant that in general the nurses overestimated the BP except in patients with severe hypertension where it was subestimated.7 Preference for digital equipment also arose from comparing previous research data, one of which was conducted from regular healthcare data in check-ups.20 The second most common fault (65% of cases) was placing the stethoscope under the cuff, which interferes with correct audition and may lead to error.4 The observer error is a greater problem in the auscultatory method but systematic errors lead to intra and interobserver mistakes. In 25 cases the speed of BP deflation was above 2 mmHg/s, which is inappropriate. A deflation speed of >2 mmHg/s may lead to underestimation of systolic and overestimation of diastolic values, with the use of a speed of 2---3 mmHg/s in the cases in which heart beat is very low.21 The predictive value of a high number of measurements is greater than that of a single measurement in the surgery.21 Although it is recommended that under all circumstances at least two measurements of BP be made at intervals of under 1 min and that if there is a difference >5 mmHg between both a third should be done and the value averaged, this recommendation has no solid evidence to sustain it.22 In our research we considered it appropriate for a single measurement to be made when the value obtained was normal, but inappropriate when the BP was ≥140/90 mmHg, when the undertaking of 2 or more determinations was considered appropriate. In clinical practice this is highly important, since usually successive measurements have lower BP values and they are finally closest to those of the baseline situation. When the BP measurement is undertaken with a mercury device it is important for the observer to be seated so that their spine is at eye height and no parallax errors are committed.
Quality of the measurements When the quality of each of the 302 measurements performed was assessed, it was confirmed that in no cases was a totally correct technique employed, and only in 7% of cases were ≥80% of the variables appropriate. 90% of measurements had between 60% and 79% correct variables, which highlight the problem. When the quality of measurements was analysed by the different observers, a higher proportion of doctors with records in the upper quartile of those analysed was observed, in addition to more nurses in the second quartile and more student nurses in the bottom quartile (p < 0.05). This reality coincides with studies which have shown that only a minority of professionals have adhered to some of the recommendations of the AHA to measure BP, such as a research in Japan, conducted with primary care doctors, which analysed the performing of the measurement through 20 items, showing that only 8 of them were fulfilled in regular practice.23 The magnitude of the problem caused by imprecise measuring of BP may be calculated by considering the effects of a small but persistent error in measurement, since a few mmHgs of systematic error have a considerable impact on
7
each case, leading to over diagnosis, under diagnosis, or incorrect classification of HBP control. Studies have exposed the magnitude of the impact of systematic error in measuring by showing that undetectable differences when rounded up to 0 may increase or decreases HBP in over 50% and in over 40% in HBP control.5,24 Evidence has shown that reducing diastolic measurements by only 5 mmHg for 5 years reduces the relative risk of stroke by 42%, and therefore not measuring BP precisely may mean losing detection of a very favourable progress on the health of the hypertensive patient.25 The findings from this study are relevant for healthcare practice, although several limitations should be taken into account when analysing outcome. Firstly, the study was conducted by direct observation during the BP measuring procedure, which introduces an observation bias (Hawthorne effect).26 this was evident from the fact that during the first measurements the staff adopted a meticulous approach, which was gradually abandoned in successive measurements. Furthermore, the equipment was not objectively assessed with regards to calibration, and this limited the value of the reported BP results. Our findings confirm the suggested hypothesis that the quality of measurement in standard clinical practice is mostly inappropriate, and requires correction. Given that BP levels are the main factor for deciding whether to start or adjust hypertension treatment, this measurement is extremely relevant. Only the readings obtained with the recommended technique are appropriate for taking decision and predicting long-term cardiovascular risk. One possibility for improvement consists in using semi-automatic electronic equipment validated according to some of the accepted protocols.27,28 The use of these has the advantage of eliminating several of the errors committed by the observer, such as the terminal digital preference, inappropriate speed of deflation, inappropriate placement of stethoscope, errors relating to auditory problems and those relating to the difference of height between the eyes of the observer and the mercury column. Their use in standard assistance would have these advantages, although their potential limitations would have to be present such as the use of a single cuff for different arm diameters, imprecision of measurement in patients with atrial fibrillation and a percentage of varying unreliable measurements. To conclude, the main shortcomings in the procedure were made by the operator. Measuring blood pressure is a manoeuvre carried out by health professionals thousands of times per year. If the measurements are aimed at diagnosis and/or chronic management of hypertension, nonsystematic application of the established recommendations may lead to inappropriate care in a very high number of patients. It is therefore necessary to communicate to the patients the importance of a correct procedure when their BP is being measured at home or in other environments so that they bear this in mind.
Conflict of interests The authors have no conflict of interests to declare.
+Model
ARTICLE IN PRESS
8
Acknowledgements Our thanks to the healthcare professionals and patients involved in measuring blood pressure for allowing us to observe the procedure whilst it was ongoing. Also to the authorities of the Intendencia Departamental de Maldonado, RAP-ASSE, CRAME (SEMM-Mautone) and Asistencial Médica Departamental de Maldonado for allowing us to conduct this research study in their facilities. Also to the collaborators: Br. Ana Patricia Nogueira, Br. Leticia Olivera, Br. María Emilia Lasa, Br. Sara dos Santos, Br. Lucía Nadruz, Br. Santiago Cal, Br. Micaela Orihuela, Br. Santiago Sánchez.
References 1. Sandoya E, Puppo T, Vázquez H, Portos A, Castro M, Fort Z. Evolución de la hipertensión arterial en Uruguay: 1948-2011. Rev Urug Cardiol. 2012;27:377---86. 2. Comisión Honoraria para la Salud Cardiovascular del Uruguay. Mortalidad por enfermedades cardiovasculares en Uruguay 2012; 2013. Available from: http:// www.cardiosalud.org/files/documents/libro mortalidad 2012.pdf [accessed 10.06.16]. 3. James PA, Oparil S, Carter BL, Cushman WC, DennisonHimmelfarb C, Handler J, et al. 2014 Evidence-based Guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311:507---20. 4. Pickering T, Hall J, Appel L, Falkner B, Graves J, Hill M, et al. Recommendations for blood pressure measurement in humans and experimental animals. Part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research. Hypertension. 2005;45:142---6. 5. Campbell NR, Culleton BW, McKay DW. Misclassification of blood pressure by usual measurement in ambulatory physician practices. Am J Hypertens. 2005;18:1522---7. 6. Garzón-Qui˜ nones M, Gallardo-Gonzalo C, Padín-Minaya C, López-Pisa RM, Rodríguez-Latre LM. Descriptive study of ambulatory blood pressure monitoring in the Primary Care Nursing clinic. Enferm Clín. 2013;23:218---24. 7. Roubsanthisuk W, Wongsurin U, Saravich S, Buranakitjaroen P. Blood pressure determination by traditionally trained personnel is less reliable and tends to underestimate the severity of moderate to severe hypertension. Blood Press Monit. 2007;12:61---8. 8. Sandoya E. Los 10 errores más frecuentes en el manejo de la hipertensión arterial. Tend Med. 2013;21:25---31. 9. Burgess SE, MacLaughlin EJ, Smith PA, Salcido A, Benton TJ. Blood pressure rising: differences between current clinical and recommended measurement techniques. J Am Soc Hypertens. 2011;5:484---8. 10. Netea RT, Lenders JW, Smits P, Thien T. Arm position is important for blood pressure measurement. J Hum Hypertens. 1999;13:105---9.
E. Sandoya-Olivera et al. 11. Amoore JN, Guehenec M, Scordecchia R, Scott DH. Auditing the technology used to measure blood pressure. J Med Eng Technol. 2010;34:209---16. 12. Ministerio de Salud Pública. Decreto 520/996 referente a esfigmomanómetros de mercurio. Available from: www.msp.gub.uy/andocasociado.aspx?180,15276 [accessed 16.06.16]. 13. Ministerio de Industria, Energía y Minería. Reglamento técnico de esfigmomanómetros electrónicos; 2011. Available from: http://archivo.presidencia.gub. uy/sci/decretos/2011/01/miem 396.pdf [accessed 16.06.16]. 14. Yarows SA, Qian K. Accuracy of aneroid sphygmomanometers in clinical usage: University of Michigan experience. Blood Press Monit. 2001;6:101---6. 15. McVicker JT. Blood pressure measurement --- does anyone do it right? An assessment of the reliability of equipment in use and the measurement techniques of clinicians. J Fam Plan Reprod Health Care. 2001;27:163---4. 16. Teng CL, Lim WY, Chua CZ, Teo RS, Lin KT, Yeo JC. Does a single cup of caffeinated drink significantly increase blood pressure in young adults? A randomised controlled trial. Aust Fam Physician. 2016;45:65---8. 17. Mourad A, Carney S, Gillies A, Jones B, Nanra R, Trevillian P. Arm position and blood pressure: a risk factor for hypertension. J Hum Hypertens. 2003;17:389---95. 18. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Böhm M, et al. 2013 ESH/ESC guidelines for the management of arterial hypertension. Eur Heart J. 2013;34:2159---219. 19. Wen SH, Kramer MS, Joey J, Hanley JA, Usher RH. Terminal digit preference, random error and bias in routine clinical measurement of blood pressure. J Clin Epidemiol. 1993;46:1187---93. 20. Fort Z, Portos A, Castro M, Pi˜ neyro C, Ciganda C, Bermúdez Y, et al. Factores de riesgo cardiovascular en 74.420 solicitantes de carne de salud. Rev Urug Cardiol. 2012;27:150---61. 21. Wingfield D, Freeman GK, Bulpitt CJ, Gerneral Practice Hypertension Study Group (GPHSG). Selective recording in blood pressure readings may increase subsequent mortality. QJM. 2002;95:571---7. 22. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Böhm M, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension. The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). J Hypertens. 2013;31: 1281---357. 23. Asai Y, Kawamoto R, Nago N, Kajii E. Blood pressure measurement by primary care physicians: comparison with the standard method. Nihon Koshu Eisei Zasshi. 2000;47:326---36. 24. Turner MJ, Baker AB, Kam PC. Effects of systematic errors in blood pressure measurements on the diagnosis of hypertension. Blood Press Monit. 2004;9: 249---53. 25. Collins R, Peto R, MacMahon S, Hebert P, Fiebach NH, Eberlein KA, et al. Blood pressure, stroke, and coronary heart disease. Part 2, short-term reductlons in blood pressure: overview of randomised drug trials in their epidemlological context. Lancet. 1990;335:827---38.
+Model
ARTICLE IN PRESS
Quality of blood pressure measurement in community health centres 26. McCarney R, Warner J, Iliffe S, van Haselen R, Griffin M, Fisher P. The Hawthorne effect: a randomised, controlled trial. BMC Med Res Methodol. 2007;7:30. 27. O’Brien E, Atkins N, Stergiou G, Karpettas N, Parati G, Asmar R, et al. Working Group on Blood Pressure Monitoring of the European Society of Hypertension European Society of Hypertension International Protocol revision
9
2010 for the validation of blood pressure measuring devices in adults. Blood Press Monit. 2010;15:23---38. 28. Association for the Advancement of Medical Instrumentation. Manual, electronic or automated sphygmomanometers. AAMI/CDV-1 SP10. Arlington, VA: Association for the Advancement of Medical Instrumentation; 2002.