Analysis of Physician Ability in the Measurement of Pulsus Paradoxus by Sphygmomanometry

doi:10.1378/chest.118.2.348

Chest

Volume 118, Issue 2, August 2000, Pages 348-352

https://doi.org/10.1378/chest.118.2.348 Get rights and content

Context

Measurement of pulsus paradoxus (PP) is one of several measures previously advocated in the National Heart, Lung, and Blood Institute asthma management guidelines: a pulsus of > 12 mm Hg warranted hospital admission. It is one of only a few measures that is not effort dependent and therefore important in the evaluation of patients with asthma.

Objective

Determination of physician accuracy in measuring PP.

Design

A model of induced PP in a trained healthy subject without respiratory disease was constructed with a fixed inspiratory resistance with measurement of inspiratory air pressure and beat-to-beat BP noninvasively.

Setting

Laboratory.

Participants

Attending physicians from emergency medicine and critical care disciplines who served as consecutive examiners of the trained reference subject generating known PP.

Interventions

A total of 19 attending physicians were assessed for ability in measuring PP by sphygmomanometry and by palpation. The reference subject generated 4° of PP sequentially, with each examiner blinded to the value of negative inspiratory pressure and PP. Examiners first assessed PP qualitatively by palpation, followed by its measurement within 2 min.

Main outcome measure

Proximity of physician-measured PP (PPm) to true PP (PPt).

Results

At inspiratory pressures of − 10, − 15,− 20, and − 25 mm Hg, PPt was 13.7, 16.2, 19.1, and 20.7 mm Hg, respectively (F = 14.8, p < 0.0001; analysis of variance[ANOVA]). At the same pressures, PPm was 13.1, 17.5, 17.7, and 18.0 mm Hg (p > 0.10; ANOVA). Linear regression of PPm against PPt for each examiner revealed a slope (SE) of 0.53 (0.23), and not a 1:1 relationship.

Conclusions

Past and present guidelines do not account for the challenges in measuring PP, especially in tachypneic patients. Sphygmomanometric determination of PP should be augmented by new aids developed through technological innovation.

Section snippets

Study Design

Physicians’ ability to accurately measure experimentally induced PP was assessed in a single reference subject. Attending-level physicians from emergency and critical care disciplines served as examiners who were self-selected based on subjective ability to measure PP. The study was conducted in a quiet laboratory setting, and the examiners were blinded to degree of PP. The reference subject (R.D.) was trained to generate incremental and predetermined degrees of PP by self-measured inspiratory

Results

A total of 19 examiners were used in this study; all were board certified in their respective disciplines of emergency medicine (n = 12), pediatric emergency medicine (n = 5), and pulmonary medicine/intensivists (n = 2). The combined level of experience for examiners was 9.2 ± 7.4 SD years since the end of postgraduate medical training, with two of the authors (D.S. and A.M.) serving as examiners. Across all examiners, the test subject generated values (mean ± SD) of PPt as follows: 13.7 ± 2.2,

Discussion

A limitation of our study is that the examining physicians did not practice their skill in determining PP prior to measurement. However, asking emergency physicians and critical care specialists who feel comfortable measuring PP to do so in an ad hoc manner is in keeping with clinical reality. Physicians are unable to “practice” this element of physical examination unless provided with some objective criterion that presently does not exist. There were no attempted measurements of physiologic PP

ACKNOWLEDGMENTS

We wish to thank Constantine Gatsonis, PhD, for his input.

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Cited by (17)

Rapid Fire: Pericardial Effusion and Tamponade
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The ALERTA-2 Guideline. Latin America and Spain: Recommendations for the prevention and treatment of asthma exacerbations
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Clinical measures associated with FEV<inf>1</inf> in persons with asthma requiring hospital admission
2007, American Journal of Emergency Medicine
Citation Excerpt :
This finding is contrary to previous studies and to the honored position this physical sign has enjoyed in the traditions and history of medicine, as well as in National Heart Lung and Blood Institute guidelines for asthma care [7,18,30,31]. Our finding is nonetheless consistent with the recognized challenges in manually measuring pulsus paradoxus in a noisy clinical environment, particularly among those with rapid respiratory rates where the systolic difference between inspiration and expiration could be very difficult to determine [32]. We found that %PEFR was associated with %FEV1 (adjusted coefficient P = .001, see Fig. 1).
We sought to determine the association of select clinical measures of asthma severity with percent predicted forced expiratory volume in one-second (%FEV1).
We studied a prospective cohort of adult subjects (N= 129) with asthma exacerbations requiring hospital admission. Clinical data was acquired, including medical and social history, symptoms, vital signs, physical assessment, and spirometry. Predictor variables for this study included manually determined pulsus paradoxus (PP), percent predicted peak expiratory flow rate (%PEFR) and accessory muscle use. The outcome measure was %FEV1. Multiple linear regression analyses were performed to determine the independent associations between predictor variables and %FEV1.
In univariate analysis, %PEFR correlated with %FEV1 (rho = 0.77, P < .001) and PP correlated negatively with %FEV1 (rho = − 0.384, P < .001). %FEV1 was significantly lower in participants with accessory muscle use (Median %FEV1 = 37.5%, IQR: 27.0-49.0) than in those without accessory muscle use (Median %FEV1= 55.0%, IQR: 39.0-69.0), (P = .004). In multivariable analysis including the covariates %PEFR, accessory muscle use, PP, age, sex, heart rate and respiratory rate, %PEFR (P < .0001) and accessory muscle use (P = .003) remained significantly associated with %FEV1, whereas PP did not (P = .52).
Continuous noninvasive measurement of pulsus paradoxus complements medical decision making in assessment of acute asthma severity
2006, Chest
Citation Excerpt :
These data were also pooled and analyzed in a Bland-Altman plot.22 PP was induced in a healthy adult using an established technique4 by having him breathe through a fixed resistance connected to a two-way nonrebreathing valve (Hans Rudolph; Kansas City, MO) that was attached to a manometer (OEM Medical; Marshalltown, IA). Airflow resistance occurred during inspiration, whereas expiration was unimpeded.
Pulsus paradoxus (PP) is a pathophysiologic parameter that is indicative of asthma severity. The ability of PP to categorize acutely asthmatic patients in accordance with the earlier National Asthma Education and Prevention Program (NAEPP) expert panel report 1 guidelines was determined.
An arterial tonometric BP monitor, which was interfaced to an analog-digital converter, executed a periodic amplitude analysis algorithm, which computed PP in real time. The PP measurement was compared to the criterion standard of emergency physicians in determining the hospital admission vs hospital discharge disposition following the NAEPP standardized treatment. Receiver operating characteristics (ROCs) were calculated, and the PP threshold, which maximized sensitivity and specificity, was identified. In a separate laboratory investigation, PP was induced in a healthy volunteer by inspiration through a fixed resistance. Plethysmographic waveform changes, induced by PP, were measured by a second analog-to-digital converter that was connected to a pulse oximeter.
A total of 79 patients were enrolled in the study, of whom 63 met a priori inclusion criteria and had uninterrupted data acquisition. The mean PP for patients who were appropriately discharged from the hospital was 9.1 mm Hg (95% confidence interval [CI], 7.3 to 10.9 mm Hg) and differed from the PP of 17.6 mm Hg (95% CI, 13.5 to 21.8; p < 0.001) for patients admitted to the hospital/relapsed. The sensitivity and specificity for physician disposition were 0.83 and 0.89, respectively, and for PP values were 0.78 and 0.78, respectively. The Wilcoxon area under the ROC curve was 0.82 (95% CI, 0.64 to 0.99) following treatment. The risk ratio was 5.32 for hospital admission among patients with a PP of > 11.3 mm Hg. Changes in the photoplethysmography peak height were correlated to PP from the BP monitor by a regression line with a slope of 0.01V/mm Hg.
Continuous PP can aid in determining disposition among emergency department (ED) patients with acute asthma. ED physicians equipped with a PP monitor would be able to objectify the work of breathing and would more closely adhere to NAEPP guidelines. The possibility that a PP detection algorithm could reside in a pulse oximeter warrants further investigation.
Management of acute asthma in adults in the emergency department: Nonventilatory management
2010, CMAJ. Canadian Medical Association Journal
Pediatrician’s Viewpoint
2022, Indian Pediatrics

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Chest

Clinical Investigations: CardiologyAnalysis of Physician Ability in the Measurement of Pulsus Paradoxus by Sphygmomanometry

Context

Objective

Design

Setting

Participants

Interventions

Main outcome measure

Results

Conclusions

Section snippets

Study Design

Results

Discussion

ACKNOWLEDGMENTS

Am J Cardiol

Lancet

Lancet

A treatise of the asthma

Uber schwielige mediatino-pericarditis und den paradoxen puls

Berl Klin Wochenschr

Development of pulsus paradoxus in the presence of airways obstruction [letter]

N Engl J Med

Pulsus paradoxus in acute asthma in children

J Asthma

Inspiratory fall in systolic-pressure in normal and asthmatic subjects

Am J Respir Crit Care Med

The mechanism of pulsus paradoxus during acute pericardial tamponade

J Clin Invest

Echocardiographic study of the paradoxical arterial pulse in chronic obstructive lung disease

Circulation

Pulsus paradoxus: a objective measure of severity in croup

Am J Respir Crit Care Med

Clinical Investigations: Cardiology
Analysis of Physician Ability in the Measurement of Pulsus Paradoxus by Sphygmomanometry