Journal of Gerontological Nursing

Measuring Blood Pressure via Sensory Detection

Kathy King Downey, MN, RN, CS; Bonnie K Davis, MN, RN, CS

Abstract

H ypertension has no boundaries, but strikes all age brackets. More than 60 million persons in the United States either have been found to have hypertension or have reported being told by a physician that they have hypertension. ' Within this vast population lies an important subset, the elderly. In this article, elderly is defined as persons aged 65 years or older.

Approximately 40% of white people and more than 50% of black people over 65 years of age have hypertension.2 Hypertension in the elderly includes two important classifications:

Given these problems, evaluation of a third method for elderly patients to use in monitoring their own blood pressures was warranted. In 1981, Gelman and Nemati8 described a new method of self-determination of blood pressure that required only a blood pressure cuff. This sensory detection method (SDM) consisted of inflating a sphygmomanometer cuff to a point 30 mmHg above the expected systolic pressure and then feeling the rhythmic pulsation within the arm, under the cuff, as the cuff was deflated. The systolic pressure was recorded at the point where the patient sensed the onset of rhythmic pulsation. The cuff was slowly deflated further to a point at which all throbbing sensation disappeared. This point was recorded as the diastolic pressure. The SDM was closely correlated with traditional indirect and intraarterial blood pressure measurements.8 The present study was conducted to evaluate the SDM as an alternative to the traditional, indirect method (IM) that relied on Korotkoff sound detection via a stethoscope.

The null hypothesis tested was that the results of self-monitored blood pressures, over an extended period of time using the sensory detection method, were not significantly different from those obtained using the indirect method in an ambulatory, elderly population.

Methods

The first 20 men attending the hypertension clinic, who had previous experience in self-monitoring blood pressure and who volunteered to participate in the study, comprised the sample. The sample size and convenience sampling procedure were assumed to be adequate and appropriate for this exploratory investigation.

The mean age of the sample was 61.0 years (SD = 7.6 years). Their mean weight was 181.5 pounds (SD = 20.9 pounds), and their height was 69.5 inches (SD = 2.4 inches). Their mean arm circumference was 11.4 inches (SD = 1.0 inches).

Each subject was given blood pressure equipment, including a cuff of the appropriate size for his arm. The aneroid sphygmomanometers were calibrated against a mercury gauge sphygmomanometer used in the clinic. Calibrations were done at the start of the study and as indicated thereafter by discrepant blood pressure readings.

Subjects were given three training sessions, one week apart, each lasting from 30 to 60 minutes, to assess their indirect method technique and teach them the sensory detection method. During the first session, subjects demonstrated their IM technique. If problems were noted, the nurse assisted with their correction. Practice then continued until the subjects could take their blood pressures correctly. During this session, the SDM was described and subjects were asked to notice sensations in their arm while taking blood pressure twice daily using the IM for the next week.

The second session was devoted to teaching the SDM. With the patients in a sitting position the blood pressure cuff was inflated to 30 mmHg above the usual systolic pressure and then the pressure was slowly reduced. Patients were asked to acknowledge to the nurse when they first felt the throbbing feeling under the cuff and then when this throbbing disappeared.

To validate the pressure, the nurse listened and recorded both sets of results. Three trials were conducted before the nurse reviewed the…

H ypertension has no boundaries, but strikes all age brackets. More than 60 million persons in the United States either have been found to have hypertension or have reported being told by a physician that they have hypertension. ' Within this vast population lies an important subset, the elderly. In this article, elderly is defined as persons aged 65 years or older.

Approximately 40% of white people and more than 50% of black people over 65 years of age have hypertension.2 Hypertension in the elderly includes two important classifications:

1. Combined systolic-diastolic hypertension (SBP≥160 with DBP≥90); and

2. Isolated systolic hypertension (SBPS≥ 160 with DBP^90).3

In both categories, there is scientific evidence that increased morbidity and mortality are associated with blood pressure elevations in people over 65 years of age.2

Effective treatment can control high blood pressure and significantly lower morbidity and mortality. However, the asymptomatic nature of the disease contributes to patient noncompliance with prescribed treatments. Recent studies indicate that patients who are actively involved in their own therapy are more likely to comply.4,5,6 Self- 4 monitoring blood pressure is a practical way to promote patient involvement. The measurements obtained provide valuable objective feedback to patients and health professionals alike. Indeed, lack of information about daily blood pressure patterns can preclude correct treatment and early detection of side effects from overmedication.

Objections to self-monitoring blood pressure concern the anxiety factor, procedural difficulties, and equipment costs. Some health professionals assume that patients will experience anxiety over the readings and, in turn, demonstrate higher blood pressures. Studies that used self-monitoring blood pressure, however, have not identified this problem.7 Instead, self-monitoring in conjunction with biofeedback procedures or relaxation exercises tends to decrease blood pressure.5

The equipment for self-monitoring can be difficult to manipulate simultaneously. At a minimum, the aneroid meter, stethoscope, and bulb must be controlled or positioned at the same time. This task requires neuromuscular coordination and auditory competence that some elderly people lack. Electronic equipment that requires only the push of a button provides an alternative to traditional blood pressure monitoring equipment. However, these devices are often too expensive for elderly people on low, fixed incomes.

Table

TABLESELF-MONITORING BLOOD PRESSURE RESULTS

TABLE

SELF-MONITORING BLOOD PRESSURE RESULTS

Given these problems, evaluation of a third method for elderly patients to use in monitoring their own blood pressures was warranted. In 1981, Gelman and Nemati8 described a new method of self-determination of blood pressure that required only a blood pressure cuff. This sensory detection method (SDM) consisted of inflating a sphygmomanometer cuff to a point 30 mmHg above the expected systolic pressure and then feeling the rhythmic pulsation within the arm, under the cuff, as the cuff was deflated. The systolic pressure was recorded at the point where the patient sensed the onset of rhythmic pulsation. The cuff was slowly deflated further to a point at which all throbbing sensation disappeared. This point was recorded as the diastolic pressure. The SDM was closely correlated with traditional indirect and intraarterial blood pressure measurements.8 The present study was conducted to evaluate the SDM as an alternative to the traditional, indirect method (IM) that relied on Korotkoff sound detection via a stethoscope.

The null hypothesis tested was that the results of self-monitored blood pressures, over an extended period of time using the sensory detection method, were not significantly different from those obtained using the indirect method in an ambulatory, elderly population.

Methods

The first 20 men attending the hypertension clinic, who had previous experience in self-monitoring blood pressure and who volunteered to participate in the study, comprised the sample. The sample size and convenience sampling procedure were assumed to be adequate and appropriate for this exploratory investigation.

The mean age of the sample was 61.0 years (SD = 7.6 years). Their mean weight was 181.5 pounds (SD = 20.9 pounds), and their height was 69.5 inches (SD = 2.4 inches). Their mean arm circumference was 11.4 inches (SD = 1.0 inches).

Each subject was given blood pressure equipment, including a cuff of the appropriate size for his arm. The aneroid sphygmomanometers were calibrated against a mercury gauge sphygmomanometer used in the clinic. Calibrations were done at the start of the study and as indicated thereafter by discrepant blood pressure readings.

Subjects were given three training sessions, one week apart, each lasting from 30 to 60 minutes, to assess their indirect method technique and teach them the sensory detection method. During the first session, subjects demonstrated their IM technique. If problems were noted, the nurse assisted with their correction. Practice then continued until the subjects could take their blood pressures correctly. During this session, the SDM was described and subjects were asked to notice sensations in their arm while taking blood pressure twice daily using the IM for the next week.

The second session was devoted to teaching the SDM. With the patients in a sitting position the blood pressure cuff was inflated to 30 mmHg above the usual systolic pressure and then the pressure was slowly reduced. Patients were asked to acknowledge to the nurse when they first felt the throbbing feeling under the cuff and then when this throbbing disappeared.

To validate the pressure, the nurse listened and recorded both sets of results. Three trials were conducted before the nurse reviewed the results with the subject. Subjects were asked to take blood pressure measurements twice daily for the next week; first with the SDM and then with the IM on each of the two occasions.

During the third session, the subjects' records were reviewed, both techniques were demonstrated to the nurse, and the subjects' questions were answered. Subjects were then asked to record blood pressures twice daily, using both methods on each occasion (SDM followed by the IM), and return to the clinic every six weeks for six months for a review of their records and blood pressure evaluation by the nurse.

Throughout the orientation and subsequent review visits, the following procedures were implemented. The same nurse who oriented a subject followed him throughout the study. Blood pressures were taken in the same extremity, with subjects seated. Discrepant results indicated on the subjects' records prompted review of techniques and replacement of malfunctioning equipment.

Two of the 20 patients gave inconsistent readings throughout the study because they failed to master either technique. These subjects were not included in the data analysis. Their ages were 54 and 57 years of age, respectively; thus both subjects were among the younger patients in the study. Neither one was overweight; a factor that could have impeded their ability to sense their blood pressures.

Results

Data analysis involved computing four mean blood pressures values (systolic morning, diastolic morning, systolic afternoon, and diastolic afternoon) for two periods during the six-month trial - the first six weeks and the last six weeks - for each of the two methods (SDM and IM). These results are presented in the Table.

None of the means were significantly different during either phase of the study for the 18 subjects who were able to learn both techniques. These results indicate that 18 out of 20 subjects (90%) were able to assess their blood pressure as adequately with the sensory detection method as they could with the traditional indirect method.

Discussion

Having patients monitor their own blood pressures at home has proven to be an excellent strategy for enlisting them as active partners in planning their care and improving their adherence to hypertension treatment regimens. More frequent reports of blood pressure levels provide health professionals with better baseline information. For the elderly, more than other age groups, these additional data may enable subsequent reductions in amount of antihypertensive medication. Less medication leads to fewer side effects, such as postural hypotension and decreased mental acuity, as well as decreased medication costs and simplified treatment regimens.

Manipulating blood pressure detection equipment has often been a barrier to self-monitoring blood pressure, especially by people with manual dexterity and hearing deficits. Results of this study support the sensory detection method as an alternative to the traditional, indirect auscultatory method. No stethoscope is required. The technique is easily learned, accurate, and less expensive than electronic methods.

Conclusion

The essence of nursing is to help patients to help themselves. The sensory detection method gives nurses an additional technique to teach elderly people who want to measure their blood pressure at home. However, for reasons yet unknown this technique of blood pressure monitoring cannot be mastered by all patients and, therefore, use of the SDM is limited. Patients who fail to learn this method are easily identified during the instruction phase and can be eliminated as prospective users. As is necessary in teaching any skill, nurses are advised to verify the effectiveness of their teaching carefully before they allow themselves and patients to rely on unsupervised results.

References

  • 1. The 1984 Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med 1984; 144:1045.
  • 2. Statement on Hypertension in the Elderly. National High Blood Pressure Education Program Coordinating Committee, National Institutes of Health, Bethesda, MD: April 1980.
  • 3. Franklin S: Geriatric hypertension. Medical Clinics of North America 1983; 67:395.
  • 4. Nessman DG, Carrahan JE, Nugent CA: Increasing compliance, patient-operated hypertension groups. Arch Intern Med 1980; 140:1427-1430.
  • 5. Pender NJ: Physiologic responses of clients with essential hypertension to progressive muscle relaxation training. Research in Nursing and Health 1984; 7:197-203.
  • 6. Viot DG: The struggle for drug compliance in hypertension. Cardiovascular Clinics 1978; 9:243-252.
  • 7. Laughlin KD, Fisher L, Sherrad DJ: Blood pressure reductions during self recording of home blood pressure. Am Heart J 1979; 98:629-634.
  • 8. Gelman ML, Nemati C: A new method of blood pressure recording that may enhance patient compliance. JAMA 1981; 246:368-370.

TABLE

SELF-MONITORING BLOOD PRESSURE RESULTS

10.3928/0098-9134-19861101-05

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