Pandemic printing: a novel 3D-printed swab for detecting SARS-CoV-2

OBJECTIVES

To design and evaluate 3D-printed nasal swabs for collection of samples for SARS-CoV-2 testing.

DESIGN

An iterative design process was employed. Laboratory evaluation included in vitro assessment of mock nasopharyngeal samples spiked with two different concentrations of gamma-irradiated SARS-CoV-2. A prospective clinical study compared SARS-CoV-2 and human cellular material recovery by 3D-printed swabs and standard nasopharyngeal swabs.

SETTING, PARTICIPANTS

Royal Melbourne Hospital, May 2020. Participants in the clinical evaluation were 50 hospital staff members attending a COVID-19 screening clinic and two inpatients with laboratory-confirmed COVID-19.

INTERVENTION

In the clinical evaluation, a flocked nasopharyngeal swab sample was collected with the Copan ESwab and a mid-nasal sample from the other nostril was collected with the 3D-printed swab.

RESULTS

In the laboratory evaluation, qualitative agreement with regard to SARS-CoV-2 detection in mock samples collected with 3D-printed swabs and two standard swabs was complete. In the clinical evaluation, qualitative agreement with regard to RNase P detection (a surrogate measure of adequate collection of human cellular material) in samples collected from 50 hospital staff members with standard and 3D-printed swabs was complete. Qualitative agreement with regard to SARS-CoV-2 detection in three pairs of 3D-printed mid-nasal and standard swab samples from two inpatients with laboratory-confirmed SARS-CoV-2 was also complete.

CONCLUSIONS

Using 3D-printed swabs to collect nasal samples for SARS-CoV-2 testing is feasible, acceptable to patients and health carers, and convenient.

Recent advances in the diagnosis and management of obstructive sleep apnea

Affecting a large number of middle-aged, frequently overweight subjects, obstructive sleep apnea (OSA) is the most common sleep related breathing disorder. Partial or complete upper airway (UA) collapse during sleep causing repeated apneic episodes, which is the leading pathophysiological mechanism underlying the disorder, results in arterial oxygen desaturation and recurrent arousals from sleep to re-establish airway patency. Untreated OSA is commonly associated with a range of adverse consequences, including cardiovascular complications, such as arterial and/or pulmonary hypertension, arrhythmias, stroke, as well as diabetes mellitus and metabolic syndrome, and motor vehicle accidents. Evidence-based guidelines are presently available for the diagnosis and management of OSA, and a variety of updated testing and treatment procedures and devices including some that are able to identify the site and degree of airway obstruction are becoming increasingly available. As the "one size fits all" approach falls to the wayside, a tailored personal therapeutic strategy is becoming increasingly popular in the field of sleep medicine. The aim of this review is to provide an overview for practicing clinicians on recent advances in the evaluation and management of obstructive sleep apnea in adults.

Validation of polyvinylidene fluoride nasal sensor to assess nasal obstruction in comparison with subjective technique

OBJECTIVE

The aim of this study is to validate the applicability of the PolyVinyliDene Fluoride (PVDF) nasal sensor to assess the nasal airflow, in healthy subjects and patients with nasal obstruction and to correlate the results with the score of Visual Analogue Scale (VAS).

METHODS

PVDF nasal sensor and VAS measurements were carried out in 50 subjects (25-healthy subjects and 25 patients). The VAS score of nasal obstruction and peak-to-peak amplitude (Vp-p) of nasal cycle measured by PVDF nasal sensors were analyzed for right nostril (RN) and left nostril (LN) in both the groups. Spearman's rho correlation was calculated. The relationship between PVDF nasal sensor measurements and severity of nasal obstruction (VAS score) were assessed by ANOVA.

RESULTS

In healthy group, the measurement of nasal airflow by PVDF nasal sensor for RN and LN were found to be 51.14±5.87% and 48.85±5.87%, respectively. In patient group, PVDF nasal sensor indicated lesser nasal airflow in the blocked nostrils (RN: 23.33±10.54% and LN: 32.24±11.54%). Moderate correlation was observed in healthy group (r=-0.710, p<0.001 for RN and r=-0.651, p<0.001 for LN), and moderate to strong correlation in patient group (r=-0.751, p<0.01 for RN and r=-0.885, p<0.0001 for LN).

CONCLUSION

PVDF nasal sensor method is a newly developed technique for measuring the nasal airflow. Moderate to strong correlation was observed between PVDF nasal sensor data and VAS scores for nasal obstruction. In our present study, PVDF nasal sensor technique successfully differentiated between healthy subjects and patients with nasal obstruction. Additionally, it can also assess severity of nasal obstruction in comparison with VAS. Thus, we propose that the PVDF nasal sensor technique could be used as a new diagnostic method to evaluate nasal obstruction in routine clinical practice.

Performance of frontloading for smear microscopy in the diagnosis of pulmonary tuberculosis: a cross-sectional study at a referral hospital in Uganda

Objective

To compare the performance of frontloading and the standard WHO method for diagnosis of pulmonary TB at Mulago Hospital in order to validate the technique in this setting.

Methods

This was a cross-sectional study in which 229 adult (≥18 years) TB suspects were consecutively enrolled. Suspects submitted three sputum samples as follows: at initial presentation, one hour after the first sample, and the next morning. The first and next morning samples formed the standard WHO method, while the first and the one hour later samples formed the frontloading method. Sample processing was by the standard N-acetyl L-cystein (NALC)-NaOH method, and fluorescent microscopy was done for both methods, while cultures of the first sample on Lowenstein-Jensen slants acted as a gold standard. The sensitivity, specificity and predictive values for the WHO standard and frontloading methods were compared.

Results

The sensitivity of both the frontloading and standard schemes was 91.1% while their specificities were 86.2% and 91.7% respectively. There was excellent agreement between the diagnostic capacity of the two methods (kappa statistic = 0.87, P<0.0001). The positive predictive value for the frontloading scheme was 87.2% and that for the standard approach was 91.9%, while the negative predictive values were 90.4% and 90.9%, respectively. Among the HIV positive patients, frontloading identified 59/79 (74.7%) culture positive samples while the standard approach identified 55/79 (69.6%). In the HIV sero-negative category, on the other hand, front-loading identified 48/110 (43.6%) culture positive samples compared to 45/110 (40.9%) by the standard approach.

Conclusion

Frontloading based on smear examination of two same-day sputum samples has a similar performance to the current standard method and would not be associated with any significant missed diagnosis. It may therefore be advocated for use in our setting so as to reduce time to completion of diagnosis and patient loss to follow-up.

Wheeze detection in the pediatric intensive care unit: comparison among physician, nurses, respiratory therapists, and a computerized respiratory sound monitor

OBJECTIVE

To correlate wheeze detection in the pediatric intensive care unit among staff members (a physician, nurses, and respiratory therapists [RTs]) and digital recordings from a computerized respiratory sound monitor (PulmoTrack).

METHODS

We prospectively studied 11 patients in the pediatric intensive care unit. A physician, nurses, and RTs auscultated the patients and recorded their opinions about the presence of wheeze at baseline and then every hour for 6 hours. The clinician auscultated while the PulmoTrack recorded the lung sounds. The data were analyzed by a technician trained in interpretation of acoustic data and by a panel of experts blinded to the source of the recorded data, who scored all tracks for the presence or absence of wheeze. The degree of correlation among the expert panel, the staff, and the PulmoTrack was evaluated with the Kappa coefficient and McNemar's test. The determinations of the expert panel were taken as the true state (accepted standard).

RESULTS

The PulmoTrack and expert panel were in agreement on detection of wheeze during inspiration, expiration, and the whole breath cycle; in all cases the Kappa coefficients were 0.54, 0.42, and 0.50 respectively. The PulmoTrack was significantly more sensitive than the physician (P = .002), nurses (P < .001), or RTs (P = .001). However, the specificity of the PulmoTrack was not significantly different from that of the physician, nurses, or RTs.

CONCLUSIONS

Between the physician, RTs, and nurses there was agreement about the presence of wheeze in critically ill patients in the pediatric intensive care unit. Compared to the objective acoustic measurements from the PulmoTrack, the intensive care unit staff was similar in their ability to detect the absence of wheeze. The PulmoTrack was better than the staff in detecting wheeze.

Monitoring flow rates and retention of inhalation techniques using the in-check dial device in adult asthmatics

The In-Check-Dial (Alliance Tech Medical, Granburg, TX) was used to determine adequacy of inhalation techniques and teaching of two different devices. Retention of adequate techniques, was assessed in 234 moderate to severe asthmatics. Inhalation techniques were assessed at periodic follow-ups divided into less than 1 month return visit, between 1 and 3 months, 3 to less than 6 months, and 6 months to less than 1 year. Proper inhalation techniques worsened at greater than 3 months after the last instruction. The use of the In-Check-Dial is a useful tool in teaching proper technique and monitoring the patient's ability to correctly use inhalation devices.

[Software for polygraphs used in scientific research]

Polygraphs--devices for simultaneous detection of several physiological parameters--are currently used in medicine in psychology. Special polygraphs are also used in scientific research. The process of data acquisition and processing in such polygraphs is usually computer-controlled. The goal of this work was to describe software for detection of polygraph signals used in cardiorespiratory system research. The software supports the experiment script language, allows hyperventilation testing, and makes it possible for the examination subject to control the data detection process.

Olfaction in rhinology--methods of assessing the sense of smell

Olfactory disorders frequently occur in rhinological disease. Different subjective and objective test methods are available to assess the sense of olfaction. Among the subjective methods, screening tests and threshold measurements are commonly used to quantify hyposmia or anosmia. Qualitative methods are available using discrimination and identification tests. Objective methods are used in research and in some medicolegal situations. Objective tests include olfactory evoked potentials, functional Magnetic Resonance Imaging and functional Positron Emission Tomography. The measurement of the sense of smell helps to assess the whole spectrum of the effects of nasal disease. This is especially important before rhinological surgery, because a non-detected smell disorder in patients with rhinological disease is common. The assessment of a pre-existing hyposmia or anosmia helps to avoid a postoperative claim that this was caused by surgery. A variety of validated screening tests for olfaction is available and they are a useful tool to document whether a patient is able to smell.

Simultaneous Cardiac and Respiratory Synchronization in Oxygen-Enhanced Magnetic Resonance Imaging of the Lung Using a Pneumotachograph for Respiratory Monitoring

OBJECTIVES

We sought to evaluate an optimized method for oxygen-enhanced magnetic resonance imaging of the lung, using electrocardiogram-trigger and a pneumotachograph for simultaneous cardiac and respiratory synchronization.

MATERIALS AND METHODS

Five series of IR-SSFSE images (echo time = 28.2 milliseconds; inversion time = 1,200 milliseconds) were obtained in 6 volunteers during the ventilation-paradigm room-air/oxygen/room-air: series 1, respiratory-triggered; series 2, cardiac-triggered; series 3, cardiac-triggered and respiratory-synchronized using the signal of the pneumatic belt; series 4, cardiac-triggered and respiratory-synchronized using the external signal of the pneumotachograph; and series 5, not cardiac-triggered and respiratory-synchronized using the signal of the pneumotachograph. Standard deviations of the lung (SI(var)) and diaphragm mismatch (DM) were measured. The relative SI change (DeltaSI) was computed from room-air and oxygen-enhanced images. Parametric maps were obtained from cross-correlation analysis of the ventilation paradigm. Mean correlation coefficients (cc) and the percentage of activated pixels over the lung (Act%) were calculated from these maps. All 5 parameters were compared among the 5 series (Friedman-analysis of variance, Dunn's posthoc test).

RESULTS

In series 4, DM and SI(var) were significantly lower than in respiratory and cardiac-triggered series (DM = 4.7 vs. 14.3 and 18.4; SI(var) = 4.9 vs. 10 and 11). In the same series cc and Act% also were significantly higher than in series 1 and 2 (cc = 0.86 vs. 0.7 and 0.6; Act% = 71.3 vs. 44.7 and 41.2). DeltaSI was not significantly different among all series.

CONCLUSIONS

Effective respiratory and cardiac synchronization can be achieved in oxygen-enhanced magnetic resonance imaging of the lung, using a pneumotachograph for real-time targeting of end-expiration.

Quantifying physical activity in daily life with questionnaires and motion sensors in COPD

Accurate assessment of the amount and intensity of physical activity in daily life is considered very important due to the close relationship between physical activity level, health, disability and mortality. For this reason, assessment of physical activity in daily life has gained interest in recent years, especially in sedentary populations, such as patients with chronic obstructive pulmonary disease (COPD). The present article aims to compare and discuss the two kinds of instruments more commonly used to quantify the amount of physical activity performed by COPD patients in daily life: subjective methods (questionnaires, diaries) and motion sensors (electronic or mechanical methods). Their characteristics are summarised and evidence of their validity, reliability and sensitivity is discussed, when available. Subjective methods have practical value mainly in providing the patients' view on their performance in activities of daily living and functional status. However, care must be taken when using subjective methods to accurately quantify the amount of daily physical activity performed. More accurate information is likely to be available with motion sensors rather than questionnaires. The selection of which motion sensor to use for quantification of physical activity in daily life should depend mainly on the purpose of its use.

Comparison of respiratory event detection by a polyvinylidene fluoride film airflow sensor and a pneumotachograph in sleep apnea patients

STUDY OBJECTIVES

Compare the ability of a polyvinylidene fluoride (PVDF) thermal sensor and a pneumotachograph to detect respiratory events in patients with obstructive sleep apnea.

DESIGN

Single night of monitoring, single blinded scorer.

SETTING

Veterans Affairs medical center.

PATIENTS

Ten male subjects with obstructive sleep apnea.

INTERVENTIONS

Nasal-oral airflow was simultaneously detected by a PVDF thermal sensor attached to the upper lip and a pneumotachograph in a mask over the nose and mouth.

MEASUREMENTS

Events were scored from display views showing only the airflow tracings of the sensor in question and the events scored from that sensor. The apnea-hypopnea index was computed using two definitions for hypopnea. Hypopnea-1 was defined as a 50% reduction in flow for > or = 10 s in duration. Hypopnea-2 was defined as any reduction in airflow for > or = 10 s associated with a 3% drop in the arterial oxygen saturation or followed by an arousal. The level of agreement (kappa) for the sensors was determined by comparing whether or not they identified candidate events determined by a second blinded scorer.

RESULTS

For the apnea-hypopnea-1 index (mean +/- SD), the event rate for the pneumotachograph (26.0 +/- 27.9 events/h) was slightly greater than that for the PVDF sensor (20.1 +/- 27.1 events/h; p < 0.05). For the apnea-hypopnea-2 index, the event rate for the pneumotachograph (29.4 +/- 26.8 events/h) and for that of the PVDF sensor (26.4 +/- 25.9 events/h) were similar (difference not significant). The mean +/- 2 SD difference was 3.0 +/- 8.5 events/h. The level of agreement between the sensors was in the "good range," whereby kappa = 0.69. For 20 randomly selected breaths per patient, the maximum deflections of the PVDF sensor varied linearly with pneumotachograph airflow deflections.

CONCLUSION

The PVDF sensor compared favorably with a "gold standard" method of detecting respiratory events during sleep in patients with obstructive sleep apnea.

Pulmonary hypertension

The modern era in cardiopulmonary medicine began in the 1940s, when Cournand and Richards pioneered right-heart catheterization. Until that time, no direct measurement of central vascular pressure had been performed in humans. Right-heart catheterization ignited an explosion of insights into function and dysfunction of the pulmonary circulation, cardiac performance, ventilation-perfusion relationships, lung-heart interactions, valvular function, and congenital heart disease. It marked the beginnings of angiocardiography with its diagnostic implications for diseases of the left heart and peripheral circulation. Pulmonary hypertension was discovered to be the consequence of a large variety of diseases that either raised pressure downstream of the pulmonary capillaries, induced vasoconstriction, increased blood flow to the lung, or obstructed the pulmonary vessels, either by embolism or in situ fibrosis. Hypoxic vasoconstriction was found to be a major cause of acute and chronic pulmonary hypertension, and surprising vasoreactivity of the pulmonary vascular bed was discovered to be present in many cases of severe pulmonary hypertension, initially in mitral stenosis. Diseases as disparate as scleroderma, cystic fibrosis, kyphoscoliosis, sleep apnea, and sickle cell disease were found to have shared consequences in the pulmonary circulation. Some of the achievements of Cournand and Richards and their scientific descendents are discussed in this article, including success in the diagnosis and treatment of idiopathic pulmonary arterial hypertension, chronic thromboembolic pulmonary hypertension, and management of hypoxic pulmonary hypertension.

Reliability and applicability of aerodynamic measures in dysphonia assessment

Aerodynamic measures are frequently used to analyse and document pathological voices. Some normative data are available for speakers from the English-speaking population. However, no data are available yet for Chinese speakers despite the fact that they are one of the largest populations in the world. The high variability of aerodynamic measures between and within subjects raises the issue of reliability and usefulness of this procedure in discriminating between normal and pathological voices. This study aimed to investigate the use of mean airflow rate and sub-glottal pressure in predicting normal and pathological voices. It also aimed to determine whether a higher number of repeated airflow measures would provide a better representation of the normative data in distinguishing normal from abnormal voices. The study provided a small set of preliminary normative data for Chinese speakers. Aerodynamic measures were collected from 56 Cantonese female adults using a Kay Elemetrics Aerophone II. The results showed that the accuracy in predicting a voice to be dysphonic or normal using aerodynamic measures was as high as 91.1%. The accuracy was found to improve when the number of measurements for each aerodynamic parameter was increased from three to five. The overlapping of data between the dysphonic and non-dysphonic groups, however, suggests that the aerodynamic measures should be used as an adjunct to assessment of voice disorders rather than as a diagnostic tool alone.

Role of lamellar body count for the prediction of neonatal respiratory distress syndrome in non-diabetic pregnant women

OBJECTIVE

Lamellar body count is a new and fast technique to establish the presence of fetal lung maturity. We have assessed the predictive ability of lamellar body count for neonatal respiratory distress syndrome (RDS) in a non-diabetic population.

STUDY DESIGN

We accessed a cohort of amniocenteses in non-diabetic women from 1998 to 2002 (n=102). Neonatal RDS was defined as need for surfactant, intubation, or continuous positive airway pressure (CPAP) in the setting of chest X-ray findings consistent with RDS. The predictive ability of lamellar body count was compared with those of lecithin/sphingomyelin (L/S) ratio and presence of phosphatidylglycerol (PG) using logistic regression analysis. The optimal threshold value of lamellar body count for prediction of neonatal RDS was established with receiver operating characteristic (ROC) curve analysis.

RESULTS

Lamellar body count ROC curve analysis identified a lamellar body count >37,000 microl(-1) as optimal diagnostic threshold for diagnosis of lung maturity, having a negative predictive value of 98%. Lamellar body count and PG, but not L/S ratio, added significantly to the prediction of RDS.

CONCLUSIONS

Lamellar body count is a reliable predictor of fetal lung maturity in non-diabetic women and it can replace the L/S ratio.

Evaluation of a portable device for diagnosing the sleep apnoea/hypopnoea syndrome

Waiting times for hospital-based monitoring of the obstructive sleep apnoea/hypopnoea syndrome (OSAHS) are rising. This study tested whether Embletta, a new portable device, may accurately diagnose OSAHS at home. A synchronous comparison to polysomnography was performed in 40 patients and a comparison of home Embletta studies with in-laboratory polysomnography was performed in 61 patients. In the synchronous study, the mean difference (polysomnography-Embletta) in apnoeas+hypopnoeas (A+H) x h(-1) in bed was 2 h(-1). In comparison to the apnoea/ hypopnoea index (AHI) x h(-1) slept, the Embletta (A+H) x h(-1) in bed differed by 8 x h(-1). These data were used to construct diagnostic categories in symptomatic patients from their Embletta results: "OSAHS" (> or = 20 (A+H) x h(-1) in bed), "possible OSAHS" (10-20 (A+H) x h(-1) in bed) or "not OSAHS" (<10 (A+H) x h(-1) in bed). In the home study, the mean difference in (A+H) x h(-1) in bed was 3 x h(-1). In comparison to the polysomnographic AHI x h(-1) slept, the Embletta (A+H) x h(-1) in bed differed by 6 +/- 14 x h(-1). Using the above classification, all nine patients categorised as not OSAHS had AHI < 15 x h(-1) slept on polysomnography and all 23 with OSAHS on Embletta had an AHI > or = 15 on polysomnography, but 18 patients fell into the possible OSAHS category potentially requiring further investigation and 11 home studies failed. Most patients were satisfactorily classified by home Embletta studies but 29 out of 61 required further investigation. The study suggested a 42% saving in diagnostic costs over polysomnography if this approach were adopted.

Evaluation of the POLYMESAM system in the diagnosis of obstructive sleep apnea syndrome

The reliability of a POLYMESAM (PM) instrument in the detection of ventilatory disorders and in the diagnosis of obstructive sleep apnea syndrome (OSAS) was evaluated in 50 subjects suspected for OSAS, simultaneously studied by polysomnography (PSG) in a sleep laboratory. Recordings were analysed by separate scorers, blinded to the results of the paired recording. The number of central (Ac), obstructive (Ao) or mixed apneas (Am), of hypopneas (H), and the total number of ventilatory disorders (AH) per hour of time in bed (TIB) calculated on the two recordings were significantly correlated. Bland and Altman analysis showed a good agreement between AH/TIB, Ac/TIB, Am/TIB and mean AH duration; a lower Ao/TIB at PM was mirrored by a higher H/TIB. Forty-two subjects had OSAS according to an apnea/hypopnea index (AHI) > or = 10 at PSG. Due to low sleep efficiency, AH/TIB was substantially lower than AHI. However an AH/TIB > or = 5 at PM showed a sensitivity of 100% and a specificity of 71.4%, while an AH/TIB > or = 10 showed a sensitivity of 95.2% and a specificity of 100%. In conclusion, PM proved reliable for recognition of the characteristics of ventilatory disorders and for diagnosis of OSAS.

Detection of the nasal cycle

The nasal cycle is a fluctuation of nasal patency due to the stages of congestion and decongestion of the nasal mucosa on both the right and left nasal conchae. We compared the effectiveness of the rhinostereometer in detecting the presence of a nasal cycle with the acoustic rhinometer whose effectiveness we have demonstrated in previous studies. The rhinostereometer measures the horizontal range of the most anterior portion of the inferior turbinate. The acoustic rhinometer measures the volume and various cross-sectional areas of the nostril using a pulse emitted from a sound tube. Among some of the subjects tested, it was found that rhinostereometer and acoustic rhinometer measurements of nasal patency correlated reasonably well with r values up to 0.78. The overall correlation between rhinostereometry and acoustic rhinometry was not as strong at r = 0.36. Observed variations between rhinostereometry and acoustic rhinometry could be a result of certain confounding variables that may have altered the nasal cycle between measurements.