Automated versus manual blood pressure measurement a randomized crossover trial

The mean of the difference of systolic was 8. In our study 89 patients were previously diagnosed with hypertension; their difference of mean systolic was 9. Conclusions: Systolic readings from a previously validated device are not reliable when used in the ER and they show a higher degree of incongruency and inaccuracy when they are used outside validation settings.

Also, readings from the right arm tend to be more precise. Keywords: Automated oscillometer; Sphygmomanometers; blood pressure. The cardioset heart monitoring device was used for measuring BP with noninvasive BP cuff. Meanwhile, BPs were measured manually, by an adult size cuff and standard sphygmomanometer. In manual method of measurement, appropriate cuff was chosen. Intraclass correlation coefficient evaluated agreement between automated and manual BP measurements.

During the enrollment period, adults were seen in the CCU, ICU, and emergency department, and agreed to participate in our study.

The mean age of patients was A total of The mean difference between SBP was 3. Mean difference of DBP in female was 4. Mean difference of SBP was 8. Mean difference of DBP was 4. As shown in table 4 , mean difference of SBP was 4. Mean difference of SBP was Mean difference of DBP was 5. On the strength of table of ranking base on differences between the two methods of measurement, automated SBP was higher mostly in obese patient, patients admitted in CCU and ones with cardiac complaint; on the other hand, manual SBP was higher mostly in overweight patients, patients admitted in ICU and ones with neurosurgery complaints.

Based on our knowledge, this is the first independent, prospective, observational study on the potential association between BP measurement method and BP levels in Iran. The mean SBP was SBP was significantly different between the two methods, especially in patients below 60 years, hospitalized in ICU ward, overweight, MUAC below 27 cm, and with neurosurgery problems. Moreover, DBPs were more in manual method in patients with female gender, hospitalized in ICU ward, and with neurosurgery problems.

In addition, on the basis of result of ranking table, more disagreement between two method was in critical cases. Care must be taken in using automated or manual BP readings in important clinical scenarios. According to these findings, a protocol was recommended in an acute care psychiatry unit that BP must be measured manually for all patients. Myers et al. The decrease in MOBP was seen in participation in a research study, and it was not related to any specific intervention.

Heinemann et al. They concluded that the Dinamap machine can be used with some degree of confidence to measure SBP in a general population, but its DBP measurements should be considered accurate cautiously.

The manual BP measurement, especially with mercury sphygmomanometer has been used for more than years. Regarding to advances in BP recording methods, mercury method seemed to be removed from the clinics, but, mercury sphygmomanometer remains available as a reference standard until an alternative device will be recognized as much.

Studies comparing manual with automated BP measurement have shown that manual method has more levels. This difference can be decreased if some rules for automated method are followed: patients rest in a quiet room, and multiple readings considered to make a decision.

Physicians in practice can use several examining rooms for performing physical exam for patients. This measure is suitable for automated and manual method, even when the manual way is used by considering 5 minutes of rest before the BP recording. An important point for automated method is that patients should be seated in a quiet room for some minutes while readings are being taken.

If only one or two readings are considered without adequate rest, a white coat effect would interfere with recordings, as seen with the first two readings taken by BpTRU device.

Manual BP recording is highly dependent to environment condition. BP will be detected higher when taken by physicians instead of nurses, in treatment settings in comparison to non-treatment settings and at office instead of home. Hypertension is one of the leading causes of developing atherosclerosis, cerebrovascular disease, stroke, ischemic cardiac disease, congestive heart failure and myocardial infarction [ 1 ].

Elevated blood pressure is also associated with the development of renal failure and dementia [ 2 , 3 ]. HTN related diseases are on the rise and are a global burden. Physicians are thus advised to routinely check for BP elevation in all of their patients. Overestimation of BP can expose the patient to the potential adverse effects of drug treatments as well as unnecessary medical costs and dietary restrictions.

While with an underestimated reading, the patient is at a risk of HTN related diseases, which can significantly reduce life expectancy.

Therefore an accurate reading is essential [ 7 ]. There are three non-invasive modalities commonly used to check blood pressure throughout the world, namely the manual mercury sphygmomanometer, aneroid meter and the automated oscillometric device. The manual mercury sphygmomanometer is considered to be the gold standard [ 8 ] that is, if used by a trained nurse or doctor. Recently, however, there is an ongoing debate about whether mercury sphygmomanometers should be replaced with the automated oscillometric devices because of health concerns.

Mercury is a toxic substance and is considered an environmental hazard. It has been banned in various European countries such as Sweden and The Netherlands as well as in numerous hospitals in the United States [ 8 , 9 ].

Readings can also vary depending on whether the nurse or the doctor is conversing while taking the measurement and whether there is background noise or silence [ 7 , 11 ]. All these factors contribute towards possibly inaccurate BP readings, with a potential for misdiagnosis. Apart from the above-mentioned causes that are mostly associated with the manual mercury sphygmomanometer, there are causes that might influence the readings of both AO BP devices and the manual BP like respiration, emotions, tobacco, alcohol, temperature, bladder distension, pain and exercise.

Most of these are controllable, while some are non-modifiable like age, race and diurnal variation [ 12 - 15 ]. Automated Oscillometric devices are seen to be less influenced by most of these factors and recent studies indicate that they virtually eliminate the white coat response [ 16 ]. Multiple studies suggest that the AO devices should replace the conventional manual mercury sphygmomanometer, as the latter is destined to become obsolete [ 17 , 18 ].

However, with limited resources and the high costs involved in attaining the latest medical equipment, a significant question arises: Are third world countries ready for the change? This study was conducted at a tertiary care hospital in Karachi, Pakistan, using the resources at hand, with the available AO BP instruments and the mercury sphygmomanometer.

The study was conducted at a tertiary care hospital in Karachi, Pakistan. This was a double-blind randomised clinical crossover trial. Every patient was assigned two staff nurses who used an automated oscillometric blood pressure device and a manual mercury sphygmomanometer on the patient concurrently.

The device, arm for taking the reading and nurses were randomly determined. Both the nurses remained blind of the readings they recorded.

All patients were in a supine position when their BP was checked. Randomization was done by giving the staff nurses printed forms that they filled and then sealed in the same envelope for a given patient. The crossover was achieved by taking manual than auto or auto and then manual measurements. The form consisted of fields that required the name of the device, arm from which the reading was taken, presenting complaint, history of HTN, DM, IHD, renal diseases, neurological disorders, and chronic respiratory tract diseases.

The analysis was done using SPSS version Test of significance was T test and p-values of 0. Bland- Altman plots were employed to graphically represent the data. This study was done from February to May The sample size was The Emergency Department is one of the most vital departments in the hospital. Decisions made in the ED shape the rest of the therapy for the patient. EDs all over the world receive a diverse array of patients from all age groups with a variety of clinical conditions.

Accurate blood pressure measurements are pivotal for treatment, especially for patients with deteriorating conditions. In , a study suggested that substituting automated oscillometric devices for auscultatory devices could cause grave repercussions for patients in specific circumstances; and in cases of trauma or deteriorating patient condition, manual BP should be given preference [ 19 ].

Despite this, oscillometric devices are gaining popularity and are steadily replacing auscultatory devices [ 8 ]. Even at very low levels, environmental mercury can act as a potent neurotoxin and cause serious harm. Health care facilities are one of the main sources of mercury pollution via emissions from incineration of medical waste.

The WHO considers them a major occupational hazard, as inadequate care may result in dangerous exposures to patients and health care staff [ 20 ]. WHO and other organisations around the world are working towards the removal of Mercury from hospitals and other health care settings due to the potential threat it poses [ 20 ]. In , after an agreement between the American Hospitals Association and the U.

Many countries have already switched from mercury sphygmomanometers to alternative devices [ 22 ]. This makes them perfect for ambulatory readings for patients and to monitor BP at home. Primarily for this reason, oscillometric devices are gaining fame.

A bias commonly faced by physicians is white coat hypertension, and it has been proven that automated oscillometric devices substantially remove this effect leading to more accurate readings [ 23 , 24 ].

Many oscillometric devices are available in the market. Most of these devices are not put through any validation and yet they are still being sold and used by the population. Thus there is a growing concern regarding many of these devices [ 25 , 26 ]. They have compiled a list of devices that are approved for home as well as clinical use [ 28 ].

If a device fulfils the criteria set by these two organisations it can be recommended. Unfortunately, most devices are not evaluated for accuracy independently by using these two protocols [ 26 ]. Oscillometric devices can have unreliable readings when used on diabetic patients, pregnant women, elderly patients and patients with arrhythmias [ 27 , 29 ].

They have to be independently validated and also need to be calibrated at regular intervals to ensure that their readings are accurate. Oscillometric devices have been reported to overstate blood pressure and at times understate blood pressure. In both of these instances, it can put patient management at risk. It has been reported that on some devices, there is an inherent flaw in the algorithms used which leads to skipping of certain values; this can influence results [ 30 ]. In our study, the mean of difference in manual systolic and automated systolic blood pressure was 8.

This range of The plots in Figure 1 and Figure 2 show that there is significant disagreement between automated and manual devices, again certifying that automated devices should not be recommended for use in the ED. Looking at the Bland-Altman plots for systolic blood pressure readings, there appears to be a positive linear trend — as the average blood pressure is rising, the difference between manual and electronic readings subsequently called the error of electronic measurement is also rising.

Variation in a Bland — Altman plot for difference between automated and manual systolic blood pressure when compared to the mean of diastolic blood pressure. Variation in a Bland — Altman plot for difference between automated and manual diastolic blood pressure when compared to the mean of systolic blood pressure. Exploring this further, we divided the patients into three groups based on their BP readings: patients who had a manual systolic reading of below mmHg, those who had readings between mmHg and mmHg and those who had readings above mmHg.

The differences between manual and electronic readings for the three groups are given as follows. Based on the p-values, patients who had systolic blood pressure less than mmHg fell within acceptable range. We also observed differences in measurements between the left arm and the right arm, particularly for Systolic readings. SBP measured on the right arm had less error and less standard deviation as compared to measurements on the left arm. Analysing this further, we checked whether the error component of the electronic device was varying based on the arm of measurement and the actual manual blood pressure readings.

The null hypothesis was that the observed error is not different from the AAMI criteria.