UK student midwives' theoretical knowledge, confidence, and experience of intermittent auscultation of the fetal heart rate during labour: An online cross-sectional survey

AIM

This study aimed to explore student midwives' theoretical knowledge of intrapartum intermittent auscultation, their confidence in, and their experience of this mode of fetal monitoring.

DESIGN AND SETTING

An online cross-section survey with closed and open questions. Descriptive statistics were used to analyse participants' intermittent auscultation knowledge, confidence, and experience. Reflexive thematic analysis was used to identify patterns within the free text about participants' experiences.

PARTICIPANTS

Undergraduate midwifery students (n = 303) from Nursing and Midwifery Council-approved educational institutions within the United Kingdom.

FINDINGS

Most participants demonstrated good theoretical knowledge. They had witnessed the technique being used in clinical practice, and when performed, the practice was reported to be in line with national guidance. In closed questions, participants reported feeling confident in their intermittent auscultation skills; however, these data contrasted with free-text responses.

CONCLUSION

This cross-sectional survey found that student midwives possess adequate knowledge of intermittent auscultation. However, reflecting individual clinical experiences, their confidence in their ability to perform intermittent auscultation varied. A lack of opportunity to practice intermittent auscultation, organisational culture, and midwives' preferences have caused student midwives to question their capabilities with this essential clinical skill, leaving some with doubt about their competency close to registration.

A basic investigation into the optimization of cylindrical tubes used as acoustic stethoscopes for auscultation in COVID-19 diagnosis

During the COVID-19 outbreak, the auscultation of heart and lung sounds has played an important role in the comprehensive diagnosis and real-time monitoring of confirmed cases. With clinicians wearing protective clothing in isolation wards, a potato chip tube stethoscope, which is a secure and flexible substitute for a conventional stethoscope, has been used by Chinese medical workers in the first-line treatment of COVID-19. In this study, an optimal design for this simple cylindrical stethoscope is proposed based on the fundamental theory of acoustic waveguides. Analyses of the cutoff frequency, sound power transmission coefficient, and sound wave propagation in the uniform lossless tube provide theoretical guidance for selecting the geometric parameters for this simple cylindrical stethoscope. A basic investigation into the auscultatory performances of the original tube and the optimal tube with proposed dimensions was conducted both in a semi-anechoic chamber and in a quiet laboratory. Both experimental results and front-line doctors' clinical feedback endorse the proposed theoretical optimization.

[Evaluation of the use of a simulation software in the learning of cardiopulmonary auscultation in undergraduate medical students]

INTRODUCTION

Medsounds™ software allows to create an auscultation learning platform, by providing real pre-recorded cardiopulmonary sounds on virtual chests. The study aimed at comparing the skills in cardiopulmonary auscultation between students who benefited from this platform and students who did not have access to it.

METHODS

A controlled trial was conducted with 2nd year medical students randomised into three groups. Groups A, B and C received 10 h of cardiopulmonary clinical training. In addition, group B benefited from an online access to the educative platform, and group C had a demonstration of the platform during their clinical training, then an online access. The main outcome was a 3-point multiple-choice questionnaire based on 2 original case vignettes about the description of cardiopulmonary sounds. The secondary outcome was the faculty exam on high-fidelity cardiopulmonary simulator.

RESULTS

Groups A and B included 127 students, and group C 117. Students in group C had a significantly higher score than those in group A (1.72/3 versus 1.48/3; p = 0.02), without difference between the groups B and C. Students who actually had a demonstration of the platform and used it at home had a higher score than those who did not use it (1.87 versus 1.51; p = 0.01). Students who had a demonstration of the platform before using it performed a better pulmonary examination on high-fidelity simulators.

CONCLUSION

The supervised use of an online auscultation simulation software in addition to the traditional clinical training seems to improve the auscultation performances of undergraduated medical students.

Accuracy of detecting irregular cardiac rhythms via telemedicine

We evaluated the accuracy of an electronic stethoscope in the detection of irregular cardiac rhythms. Ten patients with either normal sinus rhythm or atrial fibrillation previously documented by electrocardiogram (ECG) were recruited from a local retirement community. Six senior family medicine resident physicians were asked to assess the cardiac rhythms of the subjects as either regular or irregular, in both a telemedical and an in-person examination. An ECG was obtained simultaneously as the gold standard. Forty-five of the 60 in-person assessments were correct, as were 49 of the 60 telemedicine assessments. The difference was not significant. Physician confidence in telemedical examination did not affect the accuracy of examination. The results of this study suggest that telemedicine-directed auscultation of patients may be just as successful as inperson examination for the detection of cardiac arrhythmias.

Manipulation of cognitive load variables and impact on auscultation test performance

Health profession educators have identified auscultation skill as a learning need for health professional students. This article explores the application of cognitive load theory (CLT) to designing cardiac and respiratory auscultation skill instruction for senior-level undergraduate nursing students. Three experiments assessed student auscultation performance following instructional manipulations of the three primary components of cognitive load: intrinsic, extraneous, and germane load. Study 1 evaluated the impact of intrinsic cognitive load by varying the number of diagnoses learned in one instruction session; Study 2 evaluated the impact of extraneous cognitive load by providing students with single or multiple examples of diagnoses during instruction; and Study 3 evaluated the impact of germane cognitive load by employing mixed or blocked sequences of diagnostic examples to students. Each of the three studies presents results that support CLT as explaining the influence of different types of cognitive processing on auscultation skill acquisition. We conclude with a discussion regarding CLT's usefulness as a framework for education and education research in the health professions.

A novel device for the calibration of sonic and ultrasonic recording transducers

Recently, there has been an increase in the analysis of animal vocalizations in behavioral neuroscience as a social cue or indicator of neurological integrity. Despite the multitude of researchers examining vocalizations in a variety of species, no inexpensive, tunable devices currently exist to calibrate the amplification applied to such vocalizations before data are collected. Many commercially available recording systems have analog adjustments for gain, but such methods are notoriously unreliable and highly variable. Without a consistent level of gain, the amplitudes of recorded acoustic signals cannot be reliably compared. Here, we describe an apparatus designed to fulfill this need, which we have labeled the Calibration Unit for Recording Transducers (CURT). To maximize application to various fields, its emitted frequency and amplitude are tunable to output frequencies in both human-sonic (20 Hz-20 kHz) and human-ultrasonic ranges (20 Hz-100 kHz). Additionally, it is a portable (weighing approximately 180 g), customizable, stand-alone unit, and fits a variety of microphone connector types. The CURT is also relatively low cost to build (under 250.00 USD), thereby making such a device available to as many researchers as possible in animal behavior and neuroscience.

[Diagnosis and classification of mitral valve prolapse in children and adolescents]

We examined 1734 children and adolescents with admittance diagnosis mitral valve prolapse (MVP) and confirmed its presence using accepted Framingham criteria in 32.3% of cases. Reason for overdiagnosis in other cases was incorrect interpretation of auscultation or echocardiography data. Most often MVP was familial with recessive or dominant inheritance according to genealogical analysis. Contrary to MVP in adults children and adolescents commonly had no myxomatous transformation of valves. Taking into account constitutional and physiological peculiarities of the body in children and adolescents we distinguished two forms of MVP characteristic for this age: MVP as a variant of asthenic constitution and physiological MVP. Both forms are widely spread and represent normal states for juvenile population.

Prognostic value of the labour admission test and its effectiveness compared with auscultation only: a systematic review

OBJECTIVE

To assess the effectiveness of the labour admission test in preventing adverse outcomes, compared with auscultation only, and to assess the test's prognostic value in predicting adverse outcomes.

DESIGN

Systematic review.

SETTING

Labour wards in hospitals.

POPULATION

Pregnant women in labour. Three randomised controlled trials including 11,259 women and 11 observational studies including 5831 women.

METHODS

Literature searches in Medline, EMBASE, CINAHL, SweMed, The Cochrane Central Register of Controlled Trials, reference lists from identified studies and contact with experts.

MAIN OUTCOME MEASURES

Obstetric interventions (augmentation of labour, continuous electronic fetal monitoring, epidural analgesia, fetal blood sampling and operative deliveries) and neonatal outcomes (perinatal mortality, Apgar score, seizures, resuscitation and admission to neonatal unit).

RESULTS

Meta-analyses of the controlled trials found that women randomised to the labour admission test were more likely to have minor obstetric interventions like epidural analgesia [relative risk (RR) 1.2, 95% confidence interval (95% CI) 1.1-1.4], continuous electronic fetal monitoring (RR 1.3, 95% CI 1.2-1.5) and fetal blood sampling (RR 1.3, 95% CI 1.1-1.5) compared with women randomised to auscultation on admission. There were no significant differences in any of the other outcomes. From the observational studies, prognostic value for various outcomes was found to be generally poor. Likelihood ratio (LR) for a positive test was above 10 in 2 of 28 single outcomes and between 5 and 10 in six outcomes.

CONCLUSIONS

There is no evidence supporting that the labour admission test is beneficial in low risk women.

Can airway obstruction be estimated by lung auscultation in an emergency room setting?

OBJECTIVE

Lung auscultation is a central part of the physical examination at hospital admission. In this study, the physicians' estimation of airway obstruction by auscultation was determined and compared with the degree of airway obstruction as measured by FEV(1)/FVC values.

METHODS

Two hundred and thirty-three patients consecutively admitted to the medical emergency room with chest problems were included. After taking their history, patients were auscultated by an Internal Medicine registrar. The degree of airway obstruction had to be estimated (0=no, 1=mild, 2=moderate and 3=severe obstructed) and then spirometry was performed. Airway obstruction was defined as a ratio of FEV(1)/FVC <70%. The degree of airway obstruction was defined on FEV(1)/FVC as mild (FEV(1)/FVC <70% and >50%), moderate (FEV(1)/FVC <50% >30%) and severe (FEV(1)/FVC <30%).

RESULTS

One hundred and thirty-five patients (57.9%) had no sign of airway obstruction (FEV(1)/FVC >70%). Spirometry showed a mild obstruction in 51 patients (21.9%), a moderate obstruction in 27 patients (11.6%) and a severe obstruction in 20 patients (8.6%). There was a weak but significant correlation between FEV(1)/FVC and the auscultation-based estimation of airway obstruction in Internal Medicine Registrars (Spearman's rho=0.328; P<0.001). The sensitivity to detect airway obstruction by lung auscultation was 72.6% and the specificity only 46.3%. Thus, the negative predictive value was 68% and the positive predictive value 51%. In 27 patients (9.7%), airway obstruction was missed by lung auscultation. In these 27 cases, the severity of airway obstruction was mild in 20 patients, moderate in 5 patients and severe in 2 patients. In 82 patients (29.4%) with no sign of airway obstruction (FEV(1)/FVC >70%), airway obstruction was wrongly estimated as mild in 42 patients, as moderate in 34 patients and as severe in 6 patients, respectively. By performing multiple logistic regression, normal lung auscultation was a significant and independent predictor for not having an airway obstruction (OR 2.48 (1.43-4.28); P=0.001).

CONCLUSION

Under emergency room conditions, physicians can quite accurately exclude airway obstruction by auscultation. Normal lung auscultation is an independent predictor for not having an airway obstruction. However, airway obstruction is often overestimated by auscultation; thus, spirometry should be performed.

Factors influencing cardiac auscultation proficiency in physician trainees

INTRODUCTION

We assessed the accuracy of physician trainees in identifying different cardiac sounds and examined the factors influencing their cardiac auscultation proficiency.

METHODS

A total of 106 physicians in the Family Medicine Training Programme were asked to identify 10 cardiac sounds played sequentially on the Littmann electronic stethoscope, which functioned as a surrogate patient. Their auscultation accuracy was scored numerically out of a maximum of 10. Demographical data of the physicians was collected prospectively.

RESULTS

The mean (+/-SD) auscultation proficiency score of the study population was 4.0 +/- 1.7. Physicians who graduated in 1994 or earlier fared significantly poorer than those who obtained their Bachelor of Medicine and Bachelor of Surgery degrees between 1995 and 2000 (p-value equals 0.02). Auscultation proficiency was not related to current practice, previous years of primary care, cardiology, internal medicine or paediatric medicine postings, or cumulative years of postings. Normal heart sounds were most accurately identified. Prosthetic cardiac sounds were better identified than other extra-cardiac sounds while systolic murmurs were more accurately identified than diastolic murmurs. Tachycardia had the lowest identification rate.

CONCLUSION

Our data suggest that cardiac auscultation skill declined with time, being significantly impaired eight years after graduation. We suggest that there is a need for retraining in the form of continuing medical education to address not only new knowledge and skills, but also basic skill competency.

What Is Known About Methods of Correctly Placing Gastric Tubes in Adults and Children

An abdominal radiograph is considered the "gold standard" for determining the position of flexible small-bore nasogastric/orogastric tubes. However, placement must be checked frequently while a tube is in place, and the summative radiation risk of multiple radiographs, as well as their expense, make the development of adequate bedside placement-locating methods imperative. Several methods of detecting tube placement have been investigated in adults, including: aspirating gastric contents and measuring the pH, bilirubin, pepsin, and trypsin levels; examining the visual characteristics of aspirate; placing the proximal end of the tube under water and observing for bubbles in synchrony with expirations; measuring the carbon dioxide level at the proximal end of the nasogastric/orogastric tube; auscultation for a gurgling sound over the epigastrium or left upper quadrant of the abdomen; and measuring the length from the nose/mouth to the proximal end of the tube. Many researchers have already concluded simple auscultation is not a reliable method to assess tube position because injection of air into the tracheobronchial tree or into the pleural space can produce a sound indistinguishable from that produced by injecting air into the gastrointestinal tract. In adults, only pH and bilirubin of aspirate have been shown both to reliably predict tube position and to have inexpensive simple bedside tests. In children, only pH of aspirate has been shown to be reliable. Research on gastric tube placement in children is relatively new because children are challenging to study in that they are considered a vulnerable population. This review of the literature includes results of both adult and pediatric studies. Tube placement error rates varied from 1.9% to 89.5% in adults and between 20.9% and 43.5% in children.

Aspiration Assessment and Prevention in Critically Ill Enterally Fed Patients

Providing nutrition to patients is a vitally important aspect of care. Enterally feeding even critically ill patients remains the method of choice for most prescribers; however, the decision to provide nutrition via the enteral route comes with the added concern of bronchopulmonary aspiration as a complication. The majority of the literature and research on enteral feeding is out of date and focuses primarily on ways to identify aspiration, rather then preventing it. Although much of this research and literature is not current, many valid and useful recommendations have been made that can be applied to current practice. These recommendations are synthesized in this article in an effort to improve the quality and safety of administration of enteral nutrition to critically ill patients. However, this compiled information is limited to the current resources. More research should be done to decrease the risk of aspiration in this delicate population.

Low intensity heart murmurs in boxer dogs: inter-observer variation and effects of stress testing

Inter-observer variation in the detection and grading of low intensity heart murmurs in boxer dogs was investigated. Six veterinarians with different levels of experience examined 27 boxers by cardiac auscultation. The dogs were auscultated before and after exercise, and the results were compared with phonocardiographic and echocardiographic examinations performed at rest and during two different stress tests. A subvalvular aortic ridge was identified in six dogs on two-dimensional echocardiography. Using dogs with low intensity murmurs or dogs free of heart murmurs, inter-observer agreement was positively correlated to the level of experience at rest (weighted kappa [kappa] 0.14 to 0.75), while the agreement was poor after exercise (weighted kappa 0.01 to 0.36). The presence of a subvalvular aortic ridge was associated with higher aortic flow velocities (P<0.002) and higher auscultatory murmur grading (P<0.001). There was an increase in murmur duration during one kind of stress test (P<0.001) and in aortic flow velocity during the other (P=0.001).

Carotid artery auscultation--anachronism or useful screening procedure?

Carotid bruits are supposed to indicate the presence of high-grade common carotid or extracranial internal carotid artery stenosis in a large proportion of patients. Using a stethoscope, we prospectively auscultated 273 carotid arteries of 145 patients blinded to the results of a complete extracranial and intracranial Doppler investigation including extracranial color-coded duplex ultrasound. Fifty-four arteries showed stenosis of > or = 50%-99%, or occlusion of the extracranial internal or the common carotid artery. In 25 of these arteries, a bruit was present. In 9 out of 16 patients with extracranial stenosis from 70%-99%, a bruit was detected. In one additional patient with a middle-grade external carotid artery stenosis, a bruit was also present. In seven additional patients, a bruit was present in the absence of any carotid artery stenosis, cardiac vitium or goiter. The sensitivity of carotid auscultation for the detection of a 70%-99% stenosis of the common or extracranial internal carotid artery was 56% and specificity was 91%. The positive predictive value of a bruit found during carotid auscultation was 27%, and the negative predictive value of a normal auscultation was 97%. Carotid auscultation is a useful screening procedure in the detection of carotid stenosis or occlusion, but requires confirmation by carotid ultrasound.

Fetal health surveillance in labour

OBJECTIVE

This guideline defines the standards pertaining to the application and documentation of fetal surveillance in labour that will decrease the incidence of birth asphyxia while maintaining the lowest possible rate of obstetrical intervention. Both high- and low-risk obstetrical populations are considered. It is intended that this guideline could be used by all persons providing intrapartum care in Canada, including nurses, physicians, and midwives.

OPTIONS

Consideration has been given to methods of fetal surveillance currently available in Canada, including intermittent auscultation, electronic fetal monitoring (alone and when paired with vibro-acoustic or scalp stimulation and fetal scalp blood sampling), the "admission strip," computerized heart rate analysis, fetal oxygen saturation monitoring, fetal electrocardiogram analysis, and near-infrared spectroscopy.

OUTCOMES

Short- and long-term outcomes were considered that may indicate the presence of birth asphyxia. The associated rates of operative or other labour interventions were also considered.

EVIDENCE

A comprehensive review of randomized controlled trials performed from 1995 to date and a search of the literature using Medline and the Cochrane Database of all new studies on fetal surveillance. The level of evidence has been determined using the criteria described by the Canadian Task Force on the Periodic Health Examination.

RECOMMENDATIONS

Part I: Standard Fetal Surveillance in Labour 1. Women in active labour should receive continuous close support from an appropriately trained professional. One-to-one nursing is recommended. (I-A) 2. Intermittent auscultation following an established protocol of surveillance and response (Figure 1) is the preferred method of fetal surveillance in healthy pregnancies in the active phase of labour. (I-A) 3. Labour induction requires close monitoring of uterine activity and fetal heart rate. (III-B) 4. In the presence of abnormal fetal heart rate characteristics detected by intermittent auscultation and unresponsive to resuscitative measures, increased surveillance by continuous electronic fetal monitoring or fetal scalp sampling or delivery should be instituted. (I-A) 5. Continuous intrapartum electronic fetal monitoring is recommended: a) for pregnancies where there is an increased risk of perinatal death, cerebral palsy, or neonatal encephalopathy (III-C) b) when oxytocin is being used for augmentation of labour (1-A) c) when oxytocin is being used for induction of labour (III-C). 6. With respect to continuous electronic fetal monitoring, all professionals must be familiar with the paper speed used in each case to avoid misinterpretation. The correct time should be recorded on the electronic fetal monitoring record. (III-C) 7. Electronic fetal monitoring records should be inspected and documented every 15 minutes in the active phase of labour and at least every 5 minutes in the second stage of labour. (III-C) 8. The timing of electronic fetal monitoring patterns should be determined in association with uterine contractions. The contraction frequency, duration, intensity, and resting tone should be assessed and documented. Abdominal palpation, a tocodynamometer, or an intrauterine pressure catheter may be used to facilitate the assessment. (III-C) 9. Practitioners should use standard terminology when describing fetal heart rate characteristics of an electronic fetal monitoring record. (III-C) 10. Fetal scalp blood sampling is recommended in association with electronic fetal monitoring patterns that are uninterpretable or non-reassuring, such as sustained minimal or absent variability, uncorrectable late decelerations, increasing fetal tachycardia, and abnormal FHR characteristics on auscultation. (II-3B) 11. The limited knowledge available on the use of labour admission tests warrants further research to establish the usefulness of this screening approach. (III-C) Part II: New Technologies for Fetal Surveillance in Labour 12. The use of computer-based algorithms alone to interpret fetal heart rate patterns is not recommended as a standard of care at the present time. (III-D) 13. Fetal pulse oximetry as an adjunct to electronic fetal heart monitoring in patients with non-reassuring HR status is not recommended as a standard of care at the present time. (III-D) 14. ST waveform analysis technology is under development but is not recommended as a standard of care at this time. (III-C) 15. Near-infrared spectroscopy as an adjunct to electronic fetal monitoring is currently not recommended as there is insufficient evidence to assess its efficacy in fetal surveillance. (III-D) 16. Further study of fetal pulse oximetry, ST waveform analysis, and near-infrared technology in clinical research settings is encouraged. (III-B) VALIDATION: This guideline was reviewed by the SOGC Clinical Practice Obstetrics Committee, Maternal Fetal Medicine Committee, and ALARM Committee, as well as by the Canadian Medical Protective Association.

SPONSOR

The Society of Obstetricians and Gynaecologists of Canada.

Comparison of auscultatory and oscillometric blood pressures

OBJECTIVE

To study the differences in blood pressure readings between the auscultatory and oscillometric (Dinamap model 8100; Critikon, Tampa, Fla) methods.

DESIGN

Survey of 2 blood pressure instruments.

SETTING

Public schools.

PARTICIPANTS

Seven thousand two hundred eight schoolchildren aged 5 through 17 years.

MAIN OUTCOME MEASURE

Blood pressure levels.

RESULTS

For all children combined, Dinamap systolic pressure readings were 10 mm Hg higher (95% confidence interval, -4 to 24 mm Hg) than the auscultatory systolic pressure readings. Dinamap diastolic pressure readings were 5 mm Hg higher (95% confidence interval, -14 to 23 mm Hg) than the auscultatory Korotkoff phase V diastolic pressure readings.

CONCLUSION

These findings preclude the interchange of readings by the 2 methods. Caution must be exercised in the diagnosis of hypertension when an automated device is used.

Comparison of the Omron HEM-713C automated blood pressure monitor with a standard ausculatory method using a mercury manometer

OBJECTIVES

To compare the Omron HEM-713C automated blood pressure machine with the standard ausculatory method using a mercury manometer.

DESIGN

Blood pressures of randomly selected subjects were measured using both the Omron HEM-713C and the mercury manometer.

SETTING

Dombotombo surburb in Marondera, Zimbabwe.

SUBJECTS

One hundred and sixteen subjects 25 years and above (47 males and 69 females) randomly selected in Marondera.

MAIN OUTCOME MEASURE

Systolic blood pressure and diastolic blood pressure.

RESULTS

The Omron HEM-713C passed with a grade B for both systolic and diastolic blood pressures when using the British Hypertension Society protocol. It also passed both systolic and diastolic criteria for Association of the Advancement of Medical Instrumentation.

CONCLUSION

The Omron HEM-713C compares well with the standard mercury manometer, we therefore recommend its use in both research and clinical applications which require blood pressure measurements.

The effectiveness of esophageal stethoscopy in a simulated in-flight setting

PURPOSE

Previous research has confirmed the inability of flight nurses in an airborne BO-105 helicopter to hear breath sounds using normal or amplified transthoracic stethoscopy. The purpose of this study was to determine whether esophageal stethoscopy enabled effective auscultation of breath sounds in a simulated in-flight environment.

METHODS

The cabin-sound environment of an in-flight BO-105 was recorded and recreated in an audiology laboratory, where five flight nurses were evaluated listening to taped breath sounds via an esophageal stethoscope. This audiotape model, validated in a previously published study, used a tape consisting of 24 20-second segments. Each segment, the beginning of which was marked with a beep signal, consisted of 20 seconds of silence or breath sounds. The distal (esophageal) end of the esophageal stethoscope was attached to the tape recorder; the intensity level of breath sounds heard at the stethoscope earpiece was calibrated to equate the sound level of actual esophageal breath sounds recorded on a volunteer.

RESULTS

All nurses correctly identified the 24 taped segments as silent or including breath sounds 100% of the time.

CONCLUSION

In the simulated environment tested, esophageal stethoscopy enabled 100% accuracy in identification of breath sounds, as compared with previously reported 0% efficacy for standard transthoracic auscultation. Study in the actual patient-care environment is indicated to confirm the usefulness of esophageal stethoscopy in the in-flight setting.

Confounders of auscultatory blood pressure measurement

The appropriate use of any test requires the clinician to appreciate that test's limitations. By recognizing the potential confounders of the auscultatory assessment of blood pressure, the clinician minimizes the likelihood of enacting therapeutic decisions based on inaccurate data. When approaching the treatment of a hypertensive patient, several points should be kept in mind. First, the measurement of persistent and severe hypertension in a patient receiving treatment who describes symptoms of orthostatic hypotension with apparently adequate standing blood pressure or who lacks corroborating retinal, echocardiographic, or electrocardiographic signs of hypertension should raise the concern of pseudohypertension or a white-coat response. Similarly, when one finds a normal or near-normal systolic blood pressure in a patient with a clinical picture consistent with severe hypertension, one should make a directed effort to look for an unrecognized auscultatory gap. Second, marked discrepancies in measurements as obtained by different operators or in different settings should raise concern of the white-coat response or methodologic errors by one operator, such as undercuffing, excessive pressure on the head of the stethoscope, rapid deflation of the cuff, or use of different arms. In treating hypertension in even the minimally obese patient, a special point must be made that an adequate size cuff be used for all blood pressure determinations. Third, when blood pressure is determined with the patient in any but the satndardized back-and-arm-supported seated position described above, the clinician should acknowledge the possibility that the position may alter the patient's classification. Fourth, the diagnosis and management of hypertension requires multiple measurements of blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Accuracy and reliability of 'specialized' physical therapists in auscultating tape-recorded lung sounds

This study investigated the accuracy and inter-rater reliability of 'specialized' physical therapists in the auscultation of tape-recorded lung sounds. In addition, a correlation was investigated between accuracy of interpretation and the number of years of specialization in the field of cardiorespiratory physical therapy. This research follows an earlier study which investigated the accuracy and inter-rater reliability of auscultating tape-recorded lung sounds in a 'non-specialized' cohort of physical therapists. The subjects were 26 'specialized' cardiorespiratory physical therapists working in acute urban teaching hospitals. These individuals were required to have been practising currently and exclusively for at least one year in the area of cardiorespiratory physical therapy. Participants listened with a stethoscope to five different sounds and identified them from a standardized list of terms. One of three tapes with the same lung sounds in different order was randomly selected for each physical therapist. The percentage of correct answers for all subjects was calculated. An accurate response in the detection of lung sounds was arbitrarily defined as a percentage of correct answers of 70% or greater. The difference between the pooled correct response rate of 50% and the arbitrarily set value of 70% was statistically significant (z = 2.23, p < 0.05), indicating that the 'specialized' physical therapists were not accurate in identifying lung sounds. There was no relationship evident between the accuracy and the number of years of cardiorespiratory 'specialization' (r = 0.08). Analysis of inter-rater reliability revealed 'fair agreement' (kappa = 0.26) among subjects. These results were similar to those found in the previous study.(ABSTRACT TRUNCATED AT 250 WORDS)

A simplified form of cardiotocography for antenatal fetal assessment

Antenatal cardiotocography has become the primary method of evaluation of fetal wellbeing, and the relationship between the presence of fetal heart rate accelerations in response to fetal movement and subsequent good fetal outcome has been demonstrated. However, in areas where electronic monitors are few or not available it would be useful if such accelerations could be demonstrated using the Pinard stethoscope. A prospective study involving 200 women with a singleton pregnancy of more than 34 weeks gestation was performed at Harare Maternity Hospital, Harare, Zimbabwe, when a 6 min electronic trace using an external transducer was compared with simultaneously performed 6 min manual record using the Pinard stethoscope. The findings showed that the manual record has a sensitivity of 75% and although traces with excessive base line variability would show an acceleration on the manual record, in no case with a flat trace was an acceleration noted on the manual record. This acceptable degree of sensitivity would allow for a significant decrease in the number of women being referred for electronic tracing and would be a more appropriate use of limited resources in terms of manpower and equipment.

Physical assessment by nurses: a study of nurses' use of chest auscultation as an indicator of their assessment practices

A non-experimental survey was conducted to determine if the factors such as years of practice, how physical assessment skills were learnt and how often these skills were utilised, influenced nurses' reluctance to implement physical assessment. A sample of 150 registered nurses was surveyed. Analysis indicated that the majority of respondents has been taught to listen to chest sounds (auscultation) but did not implement this skill on a daily basis. Chi square analysis indicated that younger nurses with less years of experience were more keen to learn chest auscultation skills than nurses who were older and had more years of nursing experience.

Analysis of knee vibration signals using linear prediction

Clinical methods used at present for the diagnosis of cartilage pathology in the knee are invasive in nature, and carry some risks. There exists a need for the development of a safe, objective, noninvasive method for early detection, localization, and quantification of cartilage pathology in the knee. This paper investigates the possibility of developing such a method based on an analysis of vibrations produced by joint surfaces rubbing against one another during normal movement. In particular, the method of modeling by linear prediction is used for adaptive segmentation and parameterization of knee vibration signals. Dominant poles are extracted from the model system function for each segment based on their energy contributions and bandwidths. These dominant poles represent the dominant features of the signal segments in the spectral domain. Two-dimensional feature vectors are then constructed using the first dominant pole and the ratio of power in the 40-120 Hz band to the total power of the segment. The potential use of this method to distinguish between vibrations produced by normal volunteers and patients known to have cartilage pathology (chondromalacia) is discussed.

The need for standards in recording and analysing respiratory sounds

Respiratory sounds (RSs) recorded from the chest and trachea are nowadays being electronically analysed by many investigators with a view to (i) determining the mechanisms of their production, and (ii) to develop automated diagnostic systems based on RS analysis, that objectively categorise RS as being associated with health or respiratory diseases. However, one problem that hampers this type of research is that almost every RS investigation team uses different equipment, protocols and analysis methods which, to varying degrees, makes inter-investigator results difficult to compare. The review first discusses the many variables involved in RS recording and analysis, and the different approaches used by different investigators, to highlight this problem and its consequences. Secondly, although the review cannot propose immediately acceptable guidelines and standards for RS analysis, it proposes a 'seed' set of guidelines that are 'up for discussion' between investigators in the field, the final goal being to inject a degree of standardisation in equipment and methods that are acceptable to all involved.

Blood flow in a brachial artery compressed externally by a pneumatic cuff

Blood flow in human brachial arteries, compressed by a pneumatic cuff for blood pressure measurement, is examined using several different noninvasive techniques. From the experimental results it is shown that, when arterial pressure distal to the cuff is always lower than cuff pressure, flow in the artery under the cuff becomes supercritical near the cuff downstream margin and no reflection occurs there and the reflected wave from the peripheral vascular system of the arm does not propagate beyond the cuff downstream margin. Therefore an unsteady transition from supercritical to subcritical flow occurs near the cuff downstream margin. When the peak value of distal arterial pressure exceeds cuff pressure, a reflection occurs near the cuff downstream margin. The reflection becomes stronger corresponding to decrement of the cuff pressure and the whole artery segment under the cuff inflates fully at systole. At diastole, however, the artery segment under the cuff does not collapse completely and, hence, the phenomenon becomes that of pressure wave propagation in a partially collapsed artery segment.

Possible sources of discrepancy between sphygmomanometer cuff pressure and blood pressure quantified in a collapsible-tube analogue

This paper examines the assumption that the audible events detected as Korotkov sounds in sphygmomanometry occur when blood pressure equals arm-cuff pressure. Several effects that contribute to discrepancy between these pressures are quantified using an idealised arm-and-cuff system consisting of a thick-walled collapsible tube subject to external compression along a central part of its length. The effects studied are (1) transverse pressure difference, resulting from tissues sustaining a part of the external compression through (a) circumferential bending stiffness and (b) longitudinal curvature of the tensed localised neck at the site of initial collapse, (2) longitudinal pressure difference between upstream pressure and pressure at the collapse point due to both (a) viscous and (b) inertial pressure drop. These effects are found to compensate partially for each other; the pressure within the vessel at the collapse point is less than the cuff pressure, but is also less than the blood pressure at the upstream end of the cuff. All four of the contributing terms increase proportionally to the flow-rate raised to a power greater than one, except the viscous pressure drop. Owing to a progressive shortening of the collapsed neck as flow-rate increases, the viscous term is almost independent of the flow-rate. The overall discrepancy displays less flow-rate dependency and is smaller than some of the terms which contribute to it. This means that considerable accuracy is needed if measurements of the effects are to be used to correct the raw data on cuff pressure at the time of Korotkov sound emission so as to obtain an improved estimate of the blood pressure.

The physical examination in acute cardiac ischemic syndromes

The physical examination in acute cardiac ischemia remains a valuable tool when done with skill. Ischemia without infarction alters cardiac function, and the physical examination yields findings that reflect these changes. Ischemia with infarction alters structure and function, resulting in physical findings that are usually more dramatic and of longer duration, sometimes permanent. Carefully done, the physical examination provides information that helps in management of the immediate course, predicts prognosis, and allows for better interpretation of cardiovascular tests, both invasive and noninvasive.

Comparing RCPs to physicians for the description of lung sounds: are we accurate and can we communicate?

Precise communication among clinicians of chest-auscultation findings depends on use of standardized nomenclature for lung sounds. To identify the current practice of clinicans in describing lung sounds, we surveyed physicians and respiratory care practitioners (RCPs).

MATERIALS AND METHOD

Surveys were specifically designed to identify: (1) whether RCPs and physicians use similar terms to describe adventitious lung sounds (ALS), (2) whether changes are occurring in response to the recommendations of the ATS-ACCP Ad Hoc Subcommittee on Pulmonary Nomenclature, and (3) whether RCPs and physicians differ in their ability to accurately recognize ALS. We surveyed 156 RCPs at the 1987 Annual Meeting of the American Association for Respiratory Care and 223 pulmonary physicians (PPs) and 54 nonpulmonary physicians (NPPs) at the 1988 Annual Meeting of the American College of Chest Physicians. Each survey participant was required to listen to five examples of ALS using earphones and an audiocassette player and then to write 'free-form' descriptions of what they heard. (All participants listened to the same ALS.)

RESULTS

Fine crackles and high-pitched monophonic and polyphonic wheezes were readily recognized by the majority of RCPs and physicians. Fine crackles were described as rales or crackles; high-pitched, monophonic wheezes were described as stridor or wheezes; however, high-pitched, polyphonic wheezes were usually described as wheezes. RCPs and physicians used a variety of terms to describe coarse crackles and rhonchi. The term rhonchi was frequently used inappropriately by all groups surveyed. There were no significant differences between PPs and RCPs in their ability to accurately recognize adventitious lung sounds; however, PPs were superior to NPPs (p less than 0.05) in this regard. PPs were superior to RCPs and NPPs (p less than 0.05) in appropriately using the term 'fine' for the description of crackles.

CONCLUSION

All three groups of clinicians need to improve their ability to recognize and describe lung sounds.

Differences in blood pressure levels obtained by auscultatory and oscillometric methods

Levels of blood pressure measured by the conventional auscultatory method were compared with those measured by the Dinamap Monitor (Dinamap Monitor 1846 SX, Critikon Inc, Tampa, Fla), an oscillometric device. Triplicate measurements were obtained by the two methods 10 to 15 minutes apart in 381 seated fifth-grade children, ages 10 to 13 years. The width of the air bladder of the blood pressure cuff was selected to be 40% to 50% of the circumference of the upper arm. The mean systolic and diastolic pressures (at the fourth phase of Korotkoff sounds) by the auscultatory method were 6.4 mm Hg lower and 8.7 mm Hg higher than the oscillometric systolic and diastolic blood pressures, respectively. The findings of this study suggest that published normative levels of auscultatory blood pressure may be inappropriate as a standard when blood pressure measurement is obtained by the Dinamap Monitor. Until a new set of normative Dinamap blood pressure levels becomes available, one should use equations (A = 12.8 + 0.82D for systolic, and A = 34.3 + 0.54D for diastolic blood pressures at the fourth phase of Korotkoff sounds, where A is auscultatory blood pressure and D is Dinamap blood pressure) to predict auscultatory blood pressures before Dinamap blood pressures are compared with normative auscultatory blood pressure levels.

Observer error in blood pressure measurement

This paper describes an experiment undertaken to determine observer error in measuring blood pressure by the auscultatory method. A microcomputer was used to display a simulated mercury manometer and play back tape-recorded Korotkoff sounds synchronized with the fall of the mercury column. Each observer's readings were entered into the computer, which displayed a histogram of all readings taken up to that point and thus showed the variation among observers. The procedure, which could easily be adapted for use in teaching, was used to test 311 observers drawn from physicians, nurses, medical students, nursing students and others at nine health care institutions in Ottawa. The results showed a strong bias for even-digit readings and standard deviations of roughly 5 to 6 mm Hg. The standard deviation for the systolic readings was somewhat smaller for the physicians as a group than for the nurses (3.5 v. 5.9 mm Hg). However, the standard deviations for the diastolic readings were roughly equal for these two groups (approximately 5.5 mm Hg).

Interference of cardiovascular sounds with phonopneumography in children

We have used fast Fourier transform and power spectra analysis to determine possible interference of cardiovascular sounds with the analysis of breath sounds in children. Ten normal children, 8 to 13 yr of age, were studied with sound transducer over midprecordium, right upper lobe, and right lower lobe along with simultaneously recorded ECG and air flow. Detection of R-waves facilitated sampling of sound segments at defined flow rates, with inclusion or exclusion of heart sounds. Measurements during breath-holding and without heart sounds served as baseline values. Heart sounds were only slightly attenuated over the right upper lobe. There was a considerable overlap in the power spectra of heart and breath sounds, mainly in frequencies below 100 Hz. Analysis of low-frequency components of normal breath sounds requires sampling during parts of the cardiac cycle that are free of cardiovascular sounds.