Coronary care unit patients’ and nurses’ ratings of intensity of ischaemic chest pain

David R. Thompson, Rosemary A. Webster and Terence.W. Sutton

In 100 patients admitted to a coronary care unit with a history of chest pain thought to be due to myocardial infarction, the intensity of pain was independently rated by the patient and the primary nurse caring for the patient soon after admission. Pain intensity was assessed using a visual analogue scale designed to yield a score of O-100. 10 experienced coronary care nurses who had participated in a short programme of pain assessment and management were included in the study. A strong positive correlation between the patients’ and nurses’ ratings was found. Possible explanations for these findings are discussed.

INTRODUCTION experience tends to decline over the first 12 h

after onset, most rapidly over the first 4 h (Herlitz

Amongst patients admitted to a coronary care

unit (CCU) suspected of having suffered an acute

myocardial infarction (MI), the vast majority will

complain of chest pain. Typically, the patient

describes the pain in terms of being prolonged in

duration, located behind the sternum, and

squeezing, stabbing, pressing or crushing in quali-

ty. Radiation to, or localization in, the neck, jaw,

back, shoulders or arms can occur and the pain is

often associated with nausea, vomiting, sweating, shortness of breath and weakness. The pain is typ

et al, 1986b). Although the intensity and duration

vary considerably, patients may consider the pain

to be the worst they have ever experienced

(Herlitz et al, 1986a).

Rapid and effective management of pain in the

acute phase of MI is necessary to prevent exacer-

bation of the patient’s cardiac state and other adverse effects such as anxiety, fear, sleeplessness

and perceived loss of control which may inhibit recovery. In order to achieve effective pain man-

agement, accurate pain assessment is required.

ically unrelieved by rest or nitrates and lasts for

more than 30 minutes. The intensity of the pain Pain assessment

David R. Thompson PhD, RN, FRCN, Reader, National Institute for Nursing, Radcliffe Infirmary, Oxford OX2

Pain is a complex, highly subjective and Personal

6HE, Rosemary A. Webster BSc, RN, Clinical Nurse experience which is difficult to measure with

Specialist, Coronary Care Unit, Leicester General objective criteria (Chapman et al, 1985; Hospital, Leicester iE5 4pW and Terence W. Sutton PhD, Senior Lecturer, School of Mathematics and

ChoiniCre et al, 1990). Many psychological, socio-

Computing, Leeds Metropolitan University, Leeds LS3 cultural and situational factors are known to influ-

6HE, UK ence the way individuals react to and express pain

(Requests for offprints to DRT) (Jacox, 1977; Melzack & Wall, 1982). Personal val- Menuscript accepted 16 November 7993 ues, professional or personal experience with

83

84 INTENSIVEANDCRITICALCARENURSING

pain, cultural background and occupation may

affect the observer’s inferences about an individu-

al’s pain experience (Davitz & Pendleton, 1969;

Lenburg et al, 1970). Attitudes towards personali-

ty and behaviour traits exhibited by patients may

also influence nurses’ assessment and treatment

choice of patients (Davitr & Davitz, 1975).

For those admitted to hospital with acute MI,

the assessment and management of cardiac pain

is usually the responsibility of nurses. They are the

healthcare professionals who have the most con-

tact with the patient and family and are in a

unique position to make significant contributions

to pain management (Peric-Knowlton, 1984).

The effect of physically being with the patient,

combined with genuine caring for that patient, is

deemed possibly the most important aspect of the

nurse’s contribution to pain relief (McCaffery,

1979).

A working definition of pain frequently adopt-

ed by nurses is that of McCaffery (1979) which

states that: ‘pain is whatever the experiencing per-

son says it is, existing whenever he says it does’

(p.11). This highlights the importance of the

nurse using assessment skills to interpret the

patient’s experience of pain. The nurse is thus

faced with the responsibility of assessing a subjec-

tive event experienced and described by someone

else. Despite the fact that alteration in comfort

and pain are consistently found to be one of the

most frequently cited areas of concern for nurses,

and nursing texts extol the importance of effec-

tive pain relief, research suggests that nurses’

management of pain is often inconsistent and

inadequate. Cohen (1980) concluded that total

pain relief is not a goal amongst most nurses.

There is no agreement among researchers on the

efficacy of nurses’ assessments of patients’ pain.

Studies that have compared nurses’ and patients’

assessments of pain have shown variable results.

The scenario is complicated further by the fact

that authors may reach different conclusions

based upon interpretations of similar data results

(Van der Does, 1989). Poor correlations have fre-

quently been found between nurses’ and patients’

assessments of pain and inconsistencies in man-

agement have been identified, with nurses both

underestimating (Dudley & Holm, 1984; Camp &

O’Sullivan, 1987; Harrison, 1993) and overesti-

mating (McKinley & Botti, 1991) patients’ pain

and analgesic requirements, often within the

same study (Iafrati, 1986; Choiniere et al, 1990).

Some authors have concluded that nurses are

able to assess patients pain accurately (Walkenstein,

1982; Van der Does, 1989), whereas others claim

poor correlations reflective of inaccurate pain

assessments (Hunt et al, 1977; Iafrati, 1986;

Camp, 1988; Choiniere et al, 1990; Grossman et

al, 1991; McKinley & Botti, 1991).

The reasons for inadequacies in pain assess-

ment remain tenuous. Several authors have con-

cluded that nursing experience is a significant fac-

tor in pain assessment (Choiniere et al, 1990;

Halfens et al, 1990; Fothergill-Bourbonnais &

Wilson-Barnett, 1992)) whereas others dispute

this (Walkenstein, 1982; Dudley & Holm, 1984).

Dudley & Holm (1984) also reported that job sat-

isfaction, cultural background, shift assignment

and the clinical practice area did not influence

nurses’ inferences of suffering. Nurses commonly

express their lack of knowledge and skills in the

area of pain evaluation (Watt-Watson, 1987).

Fothergill-Bourbonnais & Wilson-Barnett (1992)

found that nurses were not confident in their

knowledge of analgesics, nor did they believe that

their basic nurse education had prepared them

adequately for caring for patients in pain.

Hamilton & Edgar (1992) studied nurses’ knowl-

edge of pain control and concluded that nurses

lacked knowledge and understanding in this area.

The experience of pain may be another relevant

factor. Ketovuori (1987)) for example, found that

nurses who had experienced burn pain them-

selves rated patients’ burn pain lower than those

who had not.

There have been relatively few studies examin-

ing nurses, management of cardiac pain despite

the fact that it is recognised that the majority of

acute MI patients will be dependent upon nurses

to administer intravenous narcotic analgesia for

the relief of pain. To some extent the nature of

pain experienced by patients admitted to hospital

with acute MI has been predetermined by the

family doctor, and although nurses have a role in

differential diagnosis and in assessing the impact

of pain for the particular patient, their main role

is in assessing the magnitude of pain experienced

in order to make decisions about the amount and

INTENSIVEANDCRlTIC4LCARENURSING 85

type of analgesia to administer and to evaluate the

effect of any analgesia given. In many CCUs nurs-

es have the authority to make decisions about the

administration of analgesia without recourse to

medical opinion, and pain relief measures are

usually initiated before a diagnosis of Ml has been

confirmed.

Research suggests that pain management for

the acute MI patient by nurses is often ineffective.

2-4) years of experience of coronary care nurs-

ing, were registered nurses holding appropriate

post-basic qualifications. Each nurse had partici- pated in a short but thorough in-service study pro-

gramme on pain, including the nature of pain

and pain assessment and management, within 6

weeks prior to the study. Each nurse functioned as

a primary nurse in the CCU.

Bondestam et al (1987)) in a study of 47 acute MI

patients, found that many were not totally free Instrument

from pain in the first 24 h on the CCU. Willetts

(1989) found that less than half of the 20 patients

studied received adequate pain relief within 30 min

of the administration of analgesia, suggesting that

the dose was inadequate, and 80% of the patients

felt that their pain had never really disappeared

throughout their stay in CCU.

Correlation between nurses’ and patients’

The visual analogue scale (VAS) was chosen for

the measurement of the intensity of chest pain.

The VAS, the most commonly used instrument of

pain assessment, consists of a horizontal line 100

mm in length with anchors ‘no pain’ and ‘pain as

bad as it could be’. The subject is asked to rate the

intensity of pain by placing a cross at an appropri-

ate point on the line. Subject responses are scored

assessment of cardiac pain has also been found to at the intersection of the cross, to the nearest mm.

be variable. Bondestam et al (1987) found a posi- Thus, the VAS is designed to yield a score of

tive correlation between nurse and patient assess-

ments of pain, but that nurses underestimated

patients’ pain in 23% of comparisons and overes-

timated it in 20% of comparisons. Willetts (1989)

found 30% of nurse assessments underestimated

and 20% overestimated the severity of pain expe-

rienced by acute MI patients.

The aim of this small study was to compare

CCU patients’ and nurses’ ratings of intensity of

ischaemic chest pain.

O-100. Advantages claimed for this scale are the

fact that it can be used quickly with minimal

instructions to the respondent, and easily for scor-

ing purposes. Its simplicity places minimal

demand on sick patients who can usually grasp

the nature of the scale with little difficulty

(Chapman et al, 1985; Jensen et al, 1986;

Harrison, 1993). Use of such an instrument

avoids the use of imprecise descriptive terms

which would make comparisons difftcult and

gives subjects an infinite number of points from

which to choose. Patients’ verbal grading of their

METHODS pain has been found to correlate well with their

scores on the VAS (Murphy et al, 1988)) and the

Setting VAS has been found capable of measuring reli-

ably subtle changes in pain expression

The setting for the study was a purpose-built, (Ohanhaus & Adler, 1975; Scott & Huskisson,

eight-bedded, open-plan CCU of a large teaching 1976).

hospital. A common problem is that the use of the VAS

assumes pain to be a unidimensional experience which varies only in intensity (Chapman et al,

Subjects 1985). However, the VAS has been used to assess chest pain associated with acute MI (Herltz et al,

The subjects in this study were 10 registered nurs- 1986) and also in comparisons with nurses’ and es working in the CCU, and 100 patients admitted patients’ assessments of pain (McKinley & Botti, directly to the CCU with a history of chest pain 1991; Grossman et al, 1991; Manne et al, 1992), and a suspected diagnosis of acute MI. including pain associated with acute MI (Gaston-

The nurses, who had an average of 3 (range Johansson et al, 1991), although Bondestam et al

86 INTENSIVEANDCRITlCALCARENURSINC

(1987) found that acute MI patients had difficulty

understanding the scale due to symptoms induced by opiates.

The VA3 was felt to be appropriate for this

study as it rendered numerical data for statistical g

analysis. The nurses on the CCU were already ‘j:

using a verbal form of the scale and as assessments E

were made on admission to the CCU, most of the *g

patients would not be affected by opiates. 2:

Procedure

Pain assessment was monitored over an &week a 20 40 60 60 100 120

period by the principal researcher. In the CCU nurse score the assessment, management and evaluation of

pain were the responsibility of the primary nurse. Fig. Plot of paired pain scores produced by patients and their primary nurses.

The ten selected nurses were observed at times

when they were practising as primary nurses and

caring for patients with ischaemic chest pain and

a suspected diagnosis of acute myocardial infarc- DISCUSSION tion. At the first indication of experiencing chest

pain, the patient was asked to rate on a VAS the The findings from this study indicate good agree- intensity of the pain experienced at that moment. ment between nurses’ and patients’ ratings of As soon as possible after this, the patient’s prima- pain. Teske et al (1983) concluded that there will ry nurse was asked to rate on a separate VAS the be a discrepancy between patients’ reports and intensity of the patient’s pain. A total of 100 nurses’ ratings of the same pain. Van der Does nurse-patient pain intensity ratings were made. (1989) discussed the validity of comparing self-

reports with observers’ ratings of pain. As they

Statistical analysis have different functions and depend on different

behaviours, he concluded that both self-report A correlation and regression analysis was carried and observational measures have their limita-

out on the pairs of pain scores produced by the tions. However, this study appears to indicate that patients and the nurses. A plot of these scores is the nurses were competent at assessing cardiac given in the Figure, together with the line of best fit. pain in their patients, as the difference between

nurse and patient scores was within the limits of

RESULTS ‘correctness’ taken by several researchers (Iafrati,

1986). Failure to appreciate the magnitude of patients’

The estimated linear regression equation for pre- pain may result in the inappropriate prescription

dieting patient score from a nurse score was: and administration of analgesia. Although this

PSCORE = 7.32 t 0.955 NSCORE

(R’ = S9%, p < 0.001)

study suggests a degree of accuracy in pain assess-

ment by nurses it does not necessarily mean that

effective pain relief followed. Further research

The high value of R* indicates a strong correla- would need to be done to study the relationship

tion between the pairs of scores. The equation, between the pain score and the action taken by having a regression coefficient of approximately the nurse.

1, indicates that a patient score could be estimat- It is to be acknowledged that the VAS only mea- ed from the nurse score by the addition of about 7 sures one dimension of pain. Meinhart & points on the VAS. McCaffery (1983) identify eight characteristics

INTENSIVE AND CRITICAL CARE NURSING 87

that should be assessed when a patient complains

of pain: location; quality; pattern; intensity; exac-

erbating factors; verbal statements about the pain;

non-verbal expression and symptoms associated

with pain. Further work may be called for which

examines in more detail, these components of

nurses’ assessments of pain.

The concordance in the pain scores in this study

may have been due to the experience of the staff,

all of whom were qualified and experienced in

coronary care nursing. Experience has been

shown to be a factor in the decision-making pro-

cesses that nurses use in the assessment of cardiac

pain (Jacavone & Dostal, 1992). Also the nurses

working in a CCU are likely to expect patients to

present with a problem of chest pain and are thus

in completing the VAS, and despite its limitations

it appears to be a useful tool in the clinical setting.

It appears particularly useful in monitoring indi-

viduals’ changes in pain over time. The patients’

ability to describe their pain may be retarded

through the actual pain, limited vocabulary and

feelings such as weakness and lethargy that the MI

and/or its treatment may produce. Likewise,

nurses are likely to find it straightforward to use: it

is a simple measure which avoids deep probing

questions to the patient.

Only patients can describe their experience of

pain and so it seems sensible to utilise a method of

pain assessment that incorporates patient input

into that assessment.

alert to its significance and practised in assessing

it quantitatively. The nurses were also familiar Limitations of the study

with using a verbal form of the study instrument

and so had experience at rating patients’ pain

numerically.

The CCU operated primary nursing, and the

intimacy this entails may have encouraged the

patient to express and quantify pain, and helped

the nurse learn how the patient responds to pain.

The open-plan layout of the CCU, where nurses

and patients can see each other, may have been

conducive to nurses being more attuned with

what was happening to patients. The CCU also

had a written philosophy which stressed the

importance of pain relief.

Inadequate assessments may result when nurses

rely mainly on their own judgement or intuition

regarding a patient’s pain. Some accurate and

reliable method of utilising the patient’s assess-

ment of pain seems useful. Even when asked,

some patients may fail to communicate to nurses

the extent of their pain, often seeking to mini- mise symptoms which could indicate a deteriora-

tion in their condition (Grossman et al, 1991).

Willetts (1989) found that half of the 20 patients she studied only reported pain to a nurse when it reached an intolerable level. Having a

simple verbal numerical scale saves patients hav- ing to verbalise their perceptions and/or feelings

about the pain. It also makes it as easy for the patients to disclose a small amount of pain that they might find difficult to describe, as it does severe pain. Patients did not appear to have any difftculty

The sample size of 10 nurses is relatively small,

comprising half the nurses working in the CCU at

the time of the study. In order to test the effective-

ness of the teaching sessions on pain assessment it

would have been useful to have obtained baseline

ratings for comparison. Patients were included in

the study if they indicated verbally that they were

experiencing pain, thus those who ‘suffered in

silence’ were excluded.

Nurses have been shown to be poor at picking

up non-verbal cues for pain (Barnhouse et al,

1988) and further research examining this in rela-

tion to CCU patients would be useful.

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