Paradoxical movement of the lateral rib margin (Hoover sign) for detecting obstructive airway disease

Characterisation and Quantification of Upper Body Surface Motions for Tidal Volume Determination in Lung-Healthy Individuals

Measurement of accurate tidal volumes based on respiration-induced surface movements of the upper body would be valuable in clinical and sports monitoring applications, but most current methods lack the precision, ease of use, or cost effectiveness required for wide-scale uptake. In this paper, the theoretical ability of different sensors, such as inertial measurement units, strain gauges, or circumference measurement devices to determine tidal volumes were investigated, scrutinised and evaluated. Sixteen subjects performed different breathing patterns of different tidal volumes, while using a motion capture system to record surface motions and a spirometer as a reference to obtain tidal volumes. Subsequently, the motion-capture data were used to determine upper-body circumferences, tilt angles, distance changes, movements and accelerations-such data could potentially be measured using optical encoders, inertial measurement units, or strain gauges. From these parameters, the measurement range and correlation with the volume signal of the spirometer were determined. The highest correlations were found between the spirometer volume and upper body circumferences; surface deflection was also well correlated, while accelerations carried minor respiratory information. The ranges of thorax motion parameters measurable with common sensors and the values and correlations to respiratory volume are presented. This article thus provides a novel tool for sensor selection for a smart shirt analysis of respiration.

Accuracy of noncontact surface imaging for tidal volume and respiratory rate measurements in the ICU

Tidal volume monitoring may help minimize lung injury during respiratory assistance. Surface imaging using time-of-flight camera is a new, non-invasive, non-contact, radiation-free, and easy-to-use technique that enables tidal volume and respiratory rate measurements. The objectives of the study were to determine the accuracy of Time-of-Flight volume (VT_TOF) and respiratory rate (RR_TOF) measurements at the bedside, and to validate its application for spontaneously breathing patients under high flow nasal canula. Data analysis was performed within the ReaSTOC data-warehousing project (ClinicalTrials.gov identifier NCT02893462). All data were recorded using standard monitoring devices, and the computerized medical file. Time-of-flight technique used a Kinect V2 (Microsoft, Redmond, WA, USA) to acquire the distance information, based on measuring the phase delay between the emitted light-wave and received backscattered signals. 44 patients (32 under mechanical ventilation; 12 under high-flow nasal canula) were recorded. High correlation (r = 0.84; p < 0.001), with low bias (-1.7 mL) and acceptable deviation (75 mL) was observed between VT_TOF and VT_REF under ventilation. Similar performance was observed for respiratory rate (r = 0.91; p < 0.001; bias < 1b/min; deviation ≤ 5b/min). Measurements were possible for all patients under high-flow nasal canula, detecting overdistension in 4 patients (tidal volume > 8 mL/kg) and low ventilation in 6 patients (tidal volume < 6 mL/kg). Tidal volume monitoring using time-of-flight camera (VT_TOF) is correlated to reference values. Time-of-flight camera enables continuous and non-contact respiratory monitoring under high-flow nasal canula, and enables to detect tidal volume and respiratory rate changes, while modifying flow. It enables respiratory monitoring for spontaneously patients, especially while using high-flow nasal oxygenation.

Surface imaging for real-time patient respiratory function assessment in intensive care

PURPOSE

Monitoring of physiological parameters is a major concern in Intensive Care Units (ICU) given their role in the assessment of vital organ function. Within this context, one issue is the lack of efficient noncontact techniques for respiratory monitoring. In this paper, we present a novel noncontact solution for real-time respiratory monitoring and function assessment of ICU patients.

METHODS

The proposed system uses a Time-of-Flight depth sensor to analyze the patient's chest wall morphological changes in order to estimate multiple respiratory function parameters. The automatic detection of the patient's torso is also proposed using a deep neural network model trained on the COCO dataset. The evaluation of the proposed system was performed on a mannequin and on 16 mechanically ventilated patients (a total of 216 recordings) admitted in the ICU of the Brest University Hospital.

RESULTS

The estimation of respiratory parameters (respiratory rate and tidal volume) showed high correlation with the reference method (r = 0.99; P < 0.001 and r = 0.99; P < 0.001) in the mannequin recordings and (r = 0.95, P < 0.001 and r = 0.90, P < 0.001) for patients.

CONCLUSION

This study describes and evaluates a novel noncontact monitoring system suitable for continuous monitoring of key respiratory parameters for disease assessment of critically ill patients.

The diagnostic accuracy of lung auscultation in adult patients with acute pulmonary pathologies: a meta-analysis

The stethoscope is used as first line diagnostic tool in assessment of patients with pulmonary symptoms. However, there is much debate about the diagnostic accuracy of this instrument. This meta-analysis aims to evaluate the diagnostic accuracy of lung auscultation for the most common respiratory pathologies. Studies concerning adult patients with respiratory symptoms are included. Main outcomes are pooled estimates of sensitivity and specificity with 95% confidence intervals, likelihood ratios (LRs), area under the curve (AUC) of lung auscultation for different pulmonary pathologies and breath sounds. A meta-regression analysis is performed to reduce observed heterogeneity. For 34 studies the overall pooled sensitivity for lung auscultation is 37% and specificity 89%. LRs and AUC of auscultation for congestive heart failure, pneumonia and obstructive lung diseases are low, LR− and specificity are acceptable. Abnormal breath sounds are highly specific for (hemato)pneumothorax in patients with trauma. Results are limited by significant heterogeneity. Lung auscultation has a low sensitivity in different clinical settings and patient populations, thereby hampering its clinical utility. When better diagnostic modalities are available, they should replace lung auscultation. Only in resource limited settings, with a high prevalence of disease and in experienced hands, lung auscultation has still a role.

Physical signs in patients with chronic obstructive pulmonary disease

We reviewed the various physical signs of chronic obstructive pulmonary disease, their pathogenesis, and clinical importance. We searched PubMed, EMBASE, and the CINAHL from inception to March 2018. We used the following search terms: chronic obstructive pulmonary disease, physical examination, purse-lip breathing, breath sound intensity, forced expiratory time, abdominal paradox, Hoover's sign, barrel-shaped chest, accessory muscle use, etc. All types of studies were chosen. Globally, history taking and clinical examination of the patients is on the wane. One reason can be a significant development in the field of medical technology, resulting in overreliance on sophisticated diagnostic machines, investigative procedures, and medical tests as first-line modalities of patient's management. In resource-constrained countries, detailed history taking and physical examination should be emphasized as one of the important modalities in patient's diagnosis and management. Declining bedside skills and clinical aptitude among the physician is indeed a concern nowadays. Physical diagnosis of chronic obstructive pulmonary disease (COPD) is the quickest and reliable modalities that can lead to early diagnosis and management of COPD patients. Bedside elicitation of physical signs should always be the starting point for any diagnosis and therapeutic approach.

Correction of Paradoxical Ribcage Motion in Scoliosis by Noninvasive Ventilation

STUDY DESIGN

Observational study of ribcage motion in scoliosis.

OBJECTIVE

To see whether noninvasive ventilation corrected paradoxical inward motion of the ribs during inspiration.

SUMMARY OF BACKGROUND DATA

Paradoxical inward motion of the ribs is observed after rib fractures, low cervical cord injury, and in chronic obstructive pulmonary disease. It is not well recognized in scoliosis and the mechanism in this group has not been studied.

METHODS

Linearized magnetometers were used to measure the diameter of the ribcage. Changes in diameter during tidal breathing were recorded during spontaneous ventilation and noninvasive ventilation in 10 subjects with idiopathic or congenital thoracic scoliosis.

RESULTS

During spontaneous breathing, the median change in ribcage diameter during inspiration was -1.5 (range -2.3 to -0.8) cm. The median change in ribcage diameter during noninvasive ventilation was +0.5 (range -1.1 to +1.2) cm. Noninvasive ventilation improved paradoxical motion in all subjects, completely correcting it in six.

CONCLUSION

Paradoxical inward motion of the ribcage is seen in some subjects with severe scoliosis. This abnormal motion is improved or abolished by noninvasive ventilation. Since noninvasive ventilation takes over the work of breathing from the respiratory muscles, we suggest that inspiratory muscle contraction causes distortion of part of the ribcage in scoliosis, probably because of the abnormal orientation of diaphragmatic muscle fibers.

LEVEL OF EVIDENCE

2.

Asynchrony in respiratory movements between the pulmonary lobes in patients with COPD: continuous measurement of lung density by 4-dimensional dynamic-ventilation CT

Purpose

Four-dimensional dynamic-ventilation CT imaging demonstrates continuous movement of the lung. The aim of this study was to assess the correlation between interlobar synchrony in lung density and spirometric values in COPD patients and smokers, by measuring the continuous changes in lung density during respiration on the dynamic-ventilation CT.

Materials and methods

Thirty-two smokers, including ten with COPD, underwent dynamic-ventilation CT during free breathing. CT data were continuously reconstructed every 0.5 sec. Mean lung density (MLD) of the five lobes (right upper [RU], right middle [RM], right lower [RL], left upper [LU], and left lower [LL]) was continuously measured by commercially available software using a fixed volume of volume of interest which was placed and tracked on a single designated point in each lobe. Concordance between the MLD time curves of six pairs of lung lobes (RU-RL, RU-RM, RM-RL, LU-LL, RU-LU, and RL-LL lobes) was expressed by cross-correlation coefficients. The relationship between these cross-correlation coefficients and the forced expiratory volume in one second/forced vital capacity (FEV_1.0/FVC) values was assessed by Spearman rank correlation analysis.

Results

In all six pairs of the pulmonary lobes, the cross-correlation coefficients of the two MLD curves were significantly positively correlated with FEV_1.0/FVC (ρ =0.60–0.73, P<0.001). The mean value of the six coefficients strongly correlated with FEV_1.0/FVC (ρ =0.80, P<0.0001).

Conclusion

The synchrony of respiratory movements between the pulmonary lobes is limited or lost in patients with more severe airflow limitation.

The validity and reliability of the clinical assessment of increased work of breathing in acutely ill patients

BACKGROUND

Mechanical ventilation is frequently indicated to reduce the work of breathing. Because it cannot be measured easily at the bedside, physicians rely on surrogate measurements such as patient appearance of distress and increased breathing effort.

OBJECTIVE

We determined the validity and reliability of subjectively rating the appearance of respiratory distress and the reliability of 11 signs of increased breathing effort.

SUBJECTS

The study included consecutive, acutely ill patients requiring various levels of respiratory support.

METHODS

Blinded to each other's observations, a fellow and a critical care consultant rated the severity of distress (absent, slight, moderate, severe) after observing subjects for 10 seconds and then determined the presence of the signs of increased breathing effort.

RESULTS

A total of 149 paired examinations occurred 6±6 minutes apart. The rating of respiratory distress correlated with oxygenation, respiratory rate, and 9 signs of increased work of breathing. It had the highest intraclass correlation coefficient (0.69; 95% confidence interval, 0.59-0.78). Rating distress as moderate to severe had a sensitivity of 70%, specificity of 92%, and positive likelihood ratio of 8 for the presence of 3 or more of hypoxia, tachypnea, and any sign of increased breathing effort. Agreement was moderate (κ = 0.53-0.47) for rating of distress, nasal flaring, scalene contraction, gasping, and abdominal muscle contraction, and fair (κ = 0.36-0.23) for sternomastoid contraction, tracheal tug, and thoracoabdominal paradox.

CONCLUSION

Assessing the increased work of breathing by rating the severity of respiratory distress based on subject appearance is a valid and moderately reliable sign that predicts the presence of serious respiratory dysfunction. The reliability of the individual signs of increased breathing effort is moderate at best.

Accuracy of symptoms, signs, and C-reactive protein for early chronic obstructive pulmonary disease

BACKGROUND

Guidelines recommend detection of early chronic obstructive pulmonary disease (COPD), but evidence on the diagnostic work-up for COPD only concerns advanced and established COPD.

AIM

To quantify the accuracy of symptoms and signs for early COPD, and the added value of C-reactive protein (CRP), in primary care patients presenting with cough.

DESIGN AND SETTING

Cross-sectional diagnostic study of 73 primary care practices in the Netherlands.

METHOD

Four hundred primary care patients (182 males, mean age 63 years) older than 50 years, presenting with persistent cough (>14 days) without established COPD participated, of whom 382 completed the study. They underwent a systematic diagnostic work-up of symptoms, signs, conventional laboratory CRP level, and hospital lung functions tests, including body plethysmography, and an expert panel decided whether COPD was present (reference test). The independent value of all items was estimated by multivariable logistic regression analysis.

RESULTS

According to the expert panel, 118 patients had COPD (30%). Symptoms and signs with independent diagnostic value were age, sex, current smoking, smoking more than 20 pack-years, cardiovascular comorbidity, wheezing complaints, diminished breath sounds, and wheezing on auscultation. Combining these items resulted in an area under the receiver operating characteristic curve (ROC area) of 0.79 (95% confidence interval = 0.74 to 0.83) after internal validation. The proportion of subjects with elevated CRP was higher in those with early COPD, but CRP added no relevant diagnostic information above symptoms and signs.

CONCLUSION

In subjects presenting with persistent cough, the CRP level has no added value for detection of early COPD.

Dyspnea, chest wall hyperinflation, and rib cage distortion in exercising patients with chronic obstructive pulmonary disease

PURPOSE

Whether dyspnea, chest wall dynamic hyperinflation, and abnormalities of rib cage motion are interrelated phenomena has not been systematically evaluated in patients with chronic obstructive pulmonary disease (COPD). Our hypothesis that they are not interrelated was based on the following observations: (i) externally imposed expiratory flow limitation is associated with no rib cage distortion during strenuous incremental exercise, with indexes of hyperinflation not being correlated with dyspnea, and (ii) end-expiratory chest wall volume may either increase or decrease during exercise in patients with COPD, with those who hyperinflate being as breathless as those who do not.

METHODS

Sixteen patients breathed either room air or 50% supplemental O2 at 75% of peak exercise in randomized order. We evaluated the volume of chest wall (V(cw)) and its compartments: the upper rib cage (V(rcp)), lower rib cage (V(rca)), and abdomen (V(ab)) using optoelectronic plethysmography; rib cage distortion was assessed by measuring the phase angle shift between V(rcp) and V(rca).

RESULTS

Ten patients increased end-expiratory V(cw) (V(cw,ee)) on air. In seven hyperinflators and three non-hyperinflators, the lower rib cage paradoxed inward during inspiration with a phase angle of 63.4° ± 30.7° compared with a normal phase angle of 16.1° ± 2.3° recorded in patients without rib cage distortion. Dyspnea (by Borg scale) averaged 8.2 and 9 at the end of exercise on air in patients with and without rib cage distortion, respectively. At iso-time during exercise with oxygen, decreased dyspnea was associated with a decrease in ventilation regardless of whether patients distorted the rib cage, dynamically hyperinflated, or deflated the chest wall.

CONCLUSIONS

Dyspnea, chest wall dynamic hyperinflation, and rib cage distortion are not interrelated phenomena.

Does a decision aid help physicians to detect chronic obstructive pulmonary disease?

BACKGROUND

Numerous decision aids have been developed recently, but the value they add above that of the initial clinical assessment is not well known.

AIM

To quantify whether a formal decision aid for chronic obstructive pulmonary disease (COPD) adds diagnostic information, above the physician's clinical assessment.

DESIGN AND SETTING

Subanalysis of a diagnostic study in Dutch primary care.

METHOD

Sixty-five primary care physicians included 357 patients who attended for persistent cough and were not known to have COPD. The physicians estimated the probability of COPD after short history taking and physical examination. After this, the presence or absence of COPD was determined using results of extensive diagnostic work-up. The extent to which an 8-item decision aid for COPD, which included only symptoms and signs, added diagnostic value above the physician's estimation was quantified by the increase of the area under the receiver operating characteristic curve (ROC area), and the improvement in diagnostic risk classification across two classes: 'low probability of COPD' (<20%) and 'possible COPD' (≥20%).

RESULTS

One hundred and four patients (29%) had COPD. Adding the decision aid to the clinical assessment increased the ROC area from 0.75 (95% confidence interval [CI] = 0.70 to 0.81) to 0.84 (95% CI = 0.80 to 0.89) (P<0.005), and improved the diagnostic risk classification of the patients, such that 35 fewer patients needed spirometry testing and eight fewer COPD cases were missed.

CONCLUSION

A short decision aid for COPD added diagnostic value to the physician's clinical assessment.

The diagnostic value of history and physical examination for COPD in suspected or known cases: a systematic review

BACKGROUND

According to current guidelines, spirometry should be performed in patients suspected of chronic obstructive pulmonary disease (COPD) by the results of history taking and physical examination. However, little is known about the diagnostic value of patient history and physical examination for COPD.

OBJECTIVES

To review the existing evidence on the diagnostic value of history taking and physical examination in recognizing COPD in patients suspected of COPD.

METHODS

A systematic literature search was performed in electronic medical databases. Studies were included after using defined inclusion and exclusion criteria and judged on their methodological quality by using the Quality Assessment of Diagnostic Accuracy Studies criteria. A formal meta-analysis was not performed because all studied items of history and physical examination were investigated in only in a maximum of three studies.

RESULTS

Six studies were included. The history items dyspnoea, wheezing, previous consultation for wheezing or cough, self-reported COPD, age and smoking and the physical examination items wheezing, forced expiratory time, laryngeal height and prolonged expiration were found to have diagnostic value for COPD. These items were studied in maximally three studies and study population studies were heterogenic. The reference test for COPD in five of the six studies concerned obstructive lung disease in general and not COPD.

CONCLUSION

There is insufficient evidence to assess the value of history taking and physical examination for diagnosing COPD.

The Hoover's Sign of Pulmonary Disease: Molecular Basis and Clinical Relevance

In the 1920's, Hoover described a sign that could be considered a marker of severe airway obstruction. While readily recognizable at the bedside, it may easily be missed on a cursory physical examination. Hoover's sign refers to the inspiratory retraction of the lower intercostal spaces that occurs with obstructive airway disease. It results from alteration in dynamics of diaphragmatic contraction due to hyperinflation, resulting in traction on the rib margins by the flattened diaphragm. The sign is reported to have a sensitivity of 58% and specificity of 86% for detection of airway obstruction. Seen in up to 70% of patients with severe obstruction, this sign is associated with a patient's body mass index, severity of dyspnea and frequency of exacerbations. Hence the presence of the Hoover's sign may provide valuable prognostic information in patients with airway obstruction, and can serve to complement other clinical or functional tests. We present a clinical and molecular review of the Hoover's sign and explain how it could be utilized in the bedside and emergent management of airway disease.

Frequency of Hoover's sign in stable patients with chronic obstructive pulmonary disease

Hoover's sign (the inward motion of the lower lateral rib cage with inspiration) is conventionally considered to be a sign of severe disease in chronic obstructive pulmonary disease (COPD). However, no studies have been done regarding the frequency of Hoover's sign in patients with stable COPD. We aim to establish the frequency of Hoover's sign in a large series of stable patients with COPD and to analyse the characteristics associated with its presence. One hundred and fifty-seven consecutive patients with COPD, 150 of whom were men (95%), with a mean (standard deviation) age of 68 (8) years were included. Seventy-one patients had Hoover's sign (45%) on clinical examination. Hoover's sign was not detected in mild COPD patients, and it was present in 36% of moderate, 43% of severe and 76% of very severe COPD patients. In the multivariate analysis, dyspnea, body mass index (BMI), number of exacerbations and number of prescribed drugs were independently associated with the presence of Hoover's sign in COPD. Hoover's sign is a frequent finding in COPD, and the frequency increases with severity. Its presence is independently related to higher values of dyspnea, BMI, number of exacerbations and number of prescribed drugs.

[Paradoxical costal shift throughout inspiration (Hoover's sign) in patients admitted because of dyspnea]

OBJECTIVE

To study the frequency and diagnostic usefulness of Hoover's sign (paradoxical costal shift throughout inspiration) in patients admitted because of dyspnea.

PATIENTS AND METHODS

268 patients admitted because of dyspnea in an Internal Medicine Department were included in the study. Physical examination was carried out on the first day of admission to establish the presence of Hoover's sign.

RESULTS

Hoover's sign was present in 62 patients of 82 with a diagnosis of chronic obstructive pulmonary disease (COPD) (sensitivity: 76%), in 3 patients of 101 (3%) with a diagnosis of congestive heart failure, in 3 patients of 23 (13%) with a diagnosis asthma, and in 6 patients of 62 (10%) with other diagnoses. Specificity of Hoover's sign for EPOC diagnosis was 94%.

CONCLUSIONS

Hoover's sign is a frequent finding in patients admitted because of EPOC and is found only rarely in patients without obstructive pulmonary disease. This sign contributes useful information for the evaluation of patients admitted because of dyspnea.

Clinical implications of Hoover's sign in chronic obstructive pulmonary disease

Background: The objective of the study was to evaluate whether Hoover's sign-the paradoxical inspiratory movement of the lateral rib margin-may have clinical implications in patients with COPD. Methods: The study included two groups of male patients with stable COPD-30 with and 30 without Hoover's sign-who were matched for age and smoking habits. Spirometric values were assessed for both groups. Degree of dyspnea, measured for normal activities with the Medical Research Council (MRC) scale and for climbing two flights of stairs with the Borg scale, and utilization of health resources, including hospitalization, were compared. Results: Patients with Hoover's sign had a higher degree of dyspnea [MRC 2.2 (S.D.: 1.2) and 1.0 (0.8), p<0.0001; Borg 5.6 (2.4) and 3.1 (2.3), p=0.0001] and a higher number of hospitalizations [0.87 (1.0) and 0.27 (0.5), p=0.005] and emergency visits [2.5 (2.3) and 0.9 (2.3), p=0.01] than patient's without it. FEV(1) significantly correlated with dyspnea scales only in patients with Hoover's sign (MRC r=0.48; Borg r=0.49; p<0.05). Conclusions: Our study shows that Hoover's sign in COPD identifies a group of patients with a higher level of dyspnea and a higher use of health care resources, regardless of the degree of functional impairment. Consequently, establishing the presence of Hoover's sign would appear to be valuable in treating patients with COPD.