Percutaneous Tracheostomy With a Demistifier Canopy in the COVID-19 Era: A Safe Technique in the Intensive Care Unit.

BACKGROUND: Endoscopic percutaneous tracheostomy (PT) is a safe technique that is performed frequently by otolaryngologists and intensivists. New challenges have been identified in order to maintain the safety of this procedure during the COVID-19 pandemic. A novel approach, using a modified demistifier canopy, was developed during the first wave of the pandemic and implemented for 17 consecutive percutaneous tracheostomies in order to enhance procedural safety. METHODS: A protocol was developed after performing a literature review of tracheostomy in COVID-19 patients. A multidisciplinary tracheostomy team was established, including the departments of otolaryngology, critical care, and respiratory therapy. Simulation was performed prior to each PT, and postoperative debriefings were done. RESULTS: A protocol and technical description of PT using a modified demistifier canopy covering was written and video documented. Data were collected on 17 patients who underwent this procedure safely in our tertiary care hospital. There were no procedure-related complications, and no evidence of COVID-19 transmission to any member of the health care team during the study period. CONCLUSION: As patients continue to recover from COVID-19, their need for tracheostomy will increase. The technique described provides a safe, multidisciplinary method of performing PT in COVID-19 patients.

Introduction to aeromicrobiology

The introductory chapter introduces aeromicrobiology as a part of aerobiology essentially concerned with aerosolization, transmission, and deposition of microorganisms. Differential characteristics of the various strata of the atmosphere are described. The various groups of microorganisms, namely bacteria, archaea, fungi, protozoans, algae, and viruses, are examined, with particular attention to the forms and functions and propensity to become airborne. The indoor and outdoor sources of microorganisms as well as the natural and anthropogenic factors that modulate their aerosolization and survival in the air are elucidated. Molecular approach to sampling and analysis of bioaerosols samples is highlighted as a game changer in our understanding of airborne microbes. While emphasizing the long history of control of microorganism in the air dating back to the infancy of knowledge of germs, human-made biological agents and biocontrol agents are identified as a major threat to human existence, deserving attention, even as various conspiracy theories as in the case of SARS-CoV-2 remain unverified. © 2023 Elsevier Inc. All rights reserved.

Aerosol Generation During Nasal Airway Instrumentation.

OBJECTIVE: Airborne aerosol transmission, an established mechanism of SARS-CoV-2 spread, has been successfully mitigated in the health care setting through the adoption of universal masking. Upper airway endoscopy, however, requires direct access to the face, thereby potentially exposing the clinic environment to infectious particles. This study quantifies aerosol production during rigid nasal endoscopy (RNE) and RNE with debridement (RNED) as compared with intubation, a posited gold standard aerosol-generating procedure. STUDY DESIGN: Prospective cross-sectional study. SETTING: Subspecialty single-center clinic and surgical study. METHOD: Three aerosol detectors (NANOSCAN-3910, OPS-3330, and APS-3321) with a particle size sensitivity of 10 to 20,000 nm were utilized to detect particulate production during the clinical care of 209 patients undergoing RNE/RNED and 25 patients undergoing intubation. RESULTS: RNE and RNED produced statistically significant particles over baseline in 29.3% and 51.0% of subjects (P = .003-.049 and .002-.047, respectively). Intubation produced statistically significant particles in 31.2% (P = .001-.015). The mean ± SD particle diameter in all tests was 69.9 ± 10.5 nm with 99.7% <300 nm. There were no statistical differences in particle production among RNE, RNED, and intubation. The presence of concomitant cough, sneeze, or prolonged speech similarly did not significantly affect particle production during any procedure. CONCLUSIONS: Instrumentation of nasal airway produces airborne aerosols to a similar degree of those seen during intubation, independent of reactive patient behaviors such as cough or sneeze. These data suggest that an improved understanding is necessary of both the definition of an aerosol-generating procedure and the functional consequences of procedural aerosol generation in clinical settings.

Inhalation of virus-loaded droplets as a clinically plausible pathway to deep lung infection.

Respiratory viruses, such as SARS-CoV-2, preliminarily infect the nasopharyngeal mucosa. The mechanism of infection spread from the nasopharynx to the deep lung-which may cause a severe infection-is, however, still unclear. We propose a clinically plausible mechanism of infection spread to the deep lung through droplets, present in the nasopharynx, inhaled and transported into the lower respiratory tract. A coupled mathematical model of droplet, virus transport and virus infection kinetics is exercised to demonstrate clinically observed times to deep lung infection. The model predicts, in agreement with clinical observations, that severe infection can develop in the deep lung within 2.5-7 days of initial symptom onset. Results indicate that while fluid dynamics plays an important role in transporting the droplets, infection kinetics and immune responses determine infection growth and resolution. Immune responses, particularly antibodies and T-lymphocytes, are observed to be critically important for preventing infection severity. This reinforces the role of vaccination in preventing severe infection. Managing aerosolization of infected nasopharyngeal mucosa is additionally suggested as a strategy for minimizing infection spread and severity.

COVID-19 pandemic lesson learned- critical parameters and research needs for UVC inactivation of viral aerosols.

The COVID-19 pandemic highlighted public awareness of airborne disease transmission in indoor settings and emphasized the need for reliable air disinfection technologies. This increased awareness will carry in the post-pandemic era along with the ever-emerging SARS-CoV variants, necessitating effective and well-defined protocols, methods, and devices for air disinfection. Ultraviolet (UV)-based air disinfection demonstrated promising results in inactivating viral bioaerosols. However, the reported data diversity on the required UVC doses has hindered determining the best UVC practices and led to confusion among the public and regulators. This article reviews available information on critical parameters influencing the efficacy of a UVC air disinfection system and, consequently, the required dose including the system's components as well as operational and environmental factors. There is a consensus in the literature that the interrelation of humidity and air temperature has a significant impact on the UVC susceptibility, which translate to changing the UVC efficacy of commercialized devices in indoor settings under varying conditions. Sampling and aerosolization techniques reported to have major influence on the result interpretation and it is recommended to use several sampling methods simultaneously to generate comparable and conclusive data. We also considered the safety concerns and the potential safe alternative of UVC, far-UVC. Finally, the gaps in each critical parameter and the future research needs of the field are represented. This paper is the first step to consolidating literature towards developing a standard validation protocol for UVC air disinfection devices which is determined as the one of the research needs.

Probing Micron-sized Objects with Photoacoustic Sensing: Theory and Applications

The covid-19 respiratory illness caused by the rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulted in a worldwide pandemic over the past two years. Despite vaccinations and preventative screening methods, covid-19 remains a global issue in part due to high contagiousness and airborne transmission via droplet aerosolization. Current screening methods lack sensitivity or have a slow response time. In this study, we investigate an air-based photoacoustic spectroscopy method to rapidly detect viral RNA within aerosolized droplets. © 2022 IEEE.

Airway Management in Covid 19 Patients

BACKGROUND:- Those who work with COVID-19 patients airways are especially vulnerable. We present an empirical bit-by-bit strategy in order to guard in-hospital airway treatment of individual along COVID-19 disease, whether they are suspected or confirmed. The COVID-19 patient's airway care raises the danger of HCW exposure. Challenging extubation takes more time and might even entail many treatments with both the possibility for aerosolization, therefore rigorous attention to personal protective equipment (PPE) regulations is required to keep clinicians safe. Whenever an patient's airway risk evaluation indicates that awake tracheal intubation is the best option, therapies that produce greater secretion aerosolization should have been prevented. For decrease the chances of hypoxemia, optimal preoxygenation with a tight sealed facial mask might well be conducted beforehand to initiation. AMBU Bag during initiation should be avoided unless the patient experiences O2 depletion. Patients must be fully sedated with complete muscular relaxation for such best intubating circumstances. As a first-line technique for airway management, video laryngoscopy be suggested. If urgent invasive airway access is available, we advocate using a surgical approach like scalpelbougie-tube instead of an aerosolizing producing treatment like transtracheal jet ventilation. Invasive mechanical ventilation for individuals with COVID-19 necessitates tracheal intubation. The researchers wanted to characterise immediate intubation procedures, assess success rates & problems, and see if there was any difference in practise and results among high- and low-income nations. The researchers hypothesized that geographical & operational variables influence effective emergency airway care amongst COVID-19 patients. METHODS:- Among March 23, 2020, as well as October 24, 2020, the researchers conducted a prospective interpretive research project that would include 4,476 case of emergencies tracheal intubation done by 1,722 healthcare professionals from 607 institutions throughout 32 nation in patients of suspected or confirmed COVID-19 who required mechanical ventilation. The researchers looked into the links among intubation & operators factors, as well as the key result of first-trail success. CONCLUSIONS:- Incidence of unsuccessful tracheal intubation as well as emergency surgical airway among COVID-19 patients who required emergency airway care were reported, as well as characteristics linked to enhanced efficacy. While treating COVID-19, the chances for tracheal intubation failures must be evaluated. © The Electrochemical Society

Origin, Symptoms, Transmission and Preclusions of COVID-19

A novel coronavirus commonly known as COVID-19 has resulted in an ongoing outbreak of viral pneumonia. This pandemic started from Wuhan City, China and has spread throughout most parts of the world (210 countries). COVID-19 is a large sized, enveloped, positive stranded RNA virus. Out of the four known genera, alpha and beta corona viruses are the most commonly recognized viruses infecting human beings. COVID-19 is a new virus that is highly contagious. It spreads through infected persons in its prodromal stage which suggest its transmission is not likely through air. COVID-19 can affect people of all age groups and mostly results in the death of people with weak immune systems. Its most common reported symptoms are fever, fatigue, dry cough, lymphopenia, raised levels of lactate de-hydrogenase and, bilateral patchy shadows or ground glass opacity in the lungs (opacities may be mild damage of one lobe or all five lobes). This virus has the potential to affect pregnant women, however, its prevalence was not noticed in new-borns. Time to recovery is generally two weeks. To reduce the spread of COVID-19, observing hygienic practices like frequent hand washing, social distancing and drinking warm water and chloroquine phosphate are some of the measures to mitigate the effect of cronavirus. Copyright 2022 by the authors.

Review Article - Origin, Symptoms, Transmission and Preclusions of COVID-19

A novel coronavirus commonly known as COVID-19 has resulted in an ongoing outbreak of viral pneumonia. This pandemic started from Wuhan City, China and has spread throughout most parts of the world (210 countries). COVID-19 is a large sized, enveloped, positive stranded RNA virus. Out of the four known genera, alpha and beta corona viruses are the most commonly recognized viruses infecting human beings. COVID-19 is a new virus that is highly contagious. It spreads through infected persons in its prodromal stage which suggest its transmission is not likely through air. COVID-19 can affect people of all age groups and mostly results in the death of people with weak immune systems. Its most common reported symptoms are fever, fatigue, dry cough, lymphopenia, raised levels of lactate de-hydrogenase and, bilateral patchy shadows or ground glass opacity in the lungs (opacities may be mild damage of one lobe or all five lobes). This virus has the potential to affect pregnant women, however, its prevalence was not noticed in new-borns. Time to recovery is generally two weeks. To reduce the spread of COVID-19, observing hygienic practices like frequent hand washing, social distancing and drinking warm water and chloroquine phosphate are some of the measures to mitigate the effect of cronavirus.

Flushing a public toilet? Don't linger, since aerosolized droplets do

WATERLIT : Flushing a toilet can generate large quantities of microbe-containing aerosols depending on the design, water pressure or flushing power of the toilet. A variety of pathogens are usually found in stagnant water as well as in urine, feces and vomit. When dispersed widely through aerosolization, these pathogens can cause Ebola, norovirus that results in violent food poisoning, as well as COVID-19 caused by SARS-CoV-2

The Aerosolization of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): Phase I.

INTRODUCTION: The degree to which Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is aerosolized has yet to be determined. The aim of this study is to prove methods of detection of aerosolization of SARS-CoV-2 in hospitalized patients in anticipation of testing for aerosolization in procedural and operative settings. METHODS: In this prospective study, inpatients with SARS-CoV-2 were identified. Demographic information was obtained, and a symptom questionnaire was completed. Polytetrafluoroethylene (PTFE) filters, which were attached to an air pump, were used to detect viral aerosolization and placed in four locations in each patient's room. The filters were left in the rooms for a three-hour period. RESULTS: There were 10 patients who enrolled in the study, none of whom were vaccinated. Only two patients were more than a week from the onset of symptoms, and half of the patients received treatment for COVID with antivirals and steroids. Among ten RT-PCR positive and hospitalized patients, and four filters per patient, there was only one positive SARS-CoV-2 aerosol sample, and it was directly attached to one of the patients. Overall, there was no correlation between symptoms or symptom onset and aerosolized test result. CONCLUSIONS: The results of this suggest that there is limited aerosolization of SARS-CoV-2 and provided proof of concept for this filter sampling technique. Further studies with increased sample size should be performed in a procedural and operative setting to provide more information about SARS-CoV-2 aerosolization.

Antimicrobial Activity in the Gasphase with Hypochloric Acid

Background:The study investigated if the disinfecting potential of Hypochlorous acid (HOCl) in suspensions are transferrable to in-air cleaning applications and to what extent aerosolized HOCl solutions can deactivate indoor microbial contaminations in-air at or below legal limits. Material and Method: For the liquid disinfection we used a standard suspension disinfection test protocol. For the in-air tests we conducted several experiments where aerosolized bacterial suspensions were injected into lab chambers preloaded with different HOCl gas concentrations. Results:In suspension experiments we found sufficient efficacies for all studied organisms at minimum concentrations of 200 ppm HOCl. The in-air measurement set-up allows to follow microbe deactivation by HOCl interaction. The deactivation rate increases with the HOCl concentration, and the values are highest for Gram-negative bacteria. Conclusion:We confirmed our hypothesis of the high disinfecting power of HOCl in-air at safe levels for populated indoor places. The investigated bacteria provide a model system for infectious particles, including enveloped viruses (to which Coronavirus belongs). These early results suggest that HOCl should be further evaluated as an air-cleaning method which may complement established concepts. © 2021 by Walter de Gruyter Berlin/Boston.

Quantifying Aerosol Generation in Maxillofacial Trauma Repair Techniques.

Study Design: Cadaveric simulation study. Objective: The novel coronavirus (COVID-19), which can be transmitted via aerosolized viral particles, has directed focus on protection of healthcare workers during procedures involving the upper aerodigestive tract, including maxillofacial trauma repair. This study evaluates particle generation at different distances from open reduction and internal fixation (ORIF) of maxillofacial injuries in the intraoperative setting to reduce the risk of contracting airborne diseases such as COVID-19. Methods: Two cadaveric specimens in a simulated operating room underwent ORIF of midface and mandible fractures via intraoral incisions as well as maxillomandibular fixation (MMF) using hybrid arch bars. ORIF was performed with both self-drilling screws and with the use of a power drill for creating guide holes. Real-time aerosol concentration was measured throughout each procedure using 3 particle counters placed 0.45, 1.68, and 3.81 m (1.5, 5.5, and 12.5 feet, respectively) from the operative site. Results: There was a significant decrease in particle concentration in all procedures at 1.68 m compared to 0.45 m, but only 2 of the 5 procedures showed further significant decrease in particle concentration when going from 1.68 to 3.81 m from the operative site. There was significantly less particle concentration generated at all distances when using self-drilling techniques compared to power drilling for ORIF. Conclusions: Consideration of using self-drilling screwing techniques as well as maintaining physical distancing protocols may decrease risk of transmission of airborne diseases such as COVID-19 while in the intraoperative setting.

Recommended Approaches to Minimize Aerosol Dispersion of SARS-CoV-2 During Noninvasive Ventilatory Support Can Cause Ventilator Performance Deterioration: A Benchmark Comparative Study.

BACKGROUND: SARS-CoV-2 aerosolization during noninvasive positive-pressure ventilation may endanger health care professionals. Various circuit setups have been described to reduce virus aerosolization. However, these setups may alter ventilator performance. RESEARCH QUESTION: What are the consequences of the various suggested circuit setups on ventilator efficacy during CPAP and noninvasive ventilation (NIV)? STUDY DESIGN AND METHODS: Eight circuit setups were evaluated on a bench test model that consisted of a three-dimensional printed head and an artificial lung. Setups included a dual-limb circuit with an oronasal mask, a dual-limb circuit with a helmet interface, a single-limb circuit with a passive exhalation valve, three single-limb circuits with custom-made additional leaks, and two single-limb circuits with active exhalation valves. All setups were evaluated during NIV and CPAP. The following variables were recorded: the inspiratory flow preceding triggering of the ventilator, the inspiratory effort required to trigger the ventilator, the triggering delay, the maximal inspiratory pressure delivered by the ventilator, the tidal volume generated to the artificial lung, the total work of breathing, and the pressure-time product needed to trigger the ventilator. RESULTS: With NIV, the type of circuit setup had a significant impact on inspiratory flow preceding triggering of the ventilator (P < .0001), the inspiratory effort required to trigger the ventilator (P < .0001), the triggering delay (P < .0001), the maximal inspiratory pressure (P < .0001), the tidal volume (P = .0008), the work of breathing (P < .0001), and the pressure-time product needed to trigger the ventilator (P < .0001). Similar differences and consequences were seen with CPAP as well as with the addition of bacterial filters. Best performance was achieved with a dual-limb circuit with an oronasal mask. Worst performance was achieved with a dual-limb circuit with a helmet interface. INTERPRETATION: Ventilator performance is significantly impacted by the circuit setup. A dual-limb circuit with oronasal mask should be used preferentially.

Healthcare-associated infection impact with bioaerosol treatment and COVID-19 mitigation measures.

BACKGROUND: The real-world impact of breathing zone air purification and coronavirus disease 2019 (COVID-19) mitigation measures on healthcare-associated infections is not well documented. Engineering solutions to treat airborne transmission of disease may yield results in controlled test chambers or single rooms, but have not been reported on hospital-wide applications, and the impact of COVID-19 mitigation measures on healthcare-associated infection rates is unknown. AIM: To determine the impact of hospital-wide bioaerosol treatment and COVID-19 mitigation measures on clinical outcomes. METHODS: The impact of the step-wise addition of air disinfection technology and COVID-19 mitigation measures to standard multi-modal infection control on particle counts, viral and bacterial bioburden, and healthcare-associated infection rates was investigated in a 124-bed hospital (>100,000 patient-days over 30 months). FINDINGS AND CONCLUSION: The addition of air disinfection technology and COVID-19 mitigation measures reduced airborne ultrafine particles, altered hospital bioburden, and reduced healthcare-associated infections from 11.9 to 6.6 (per 1000 patient-days) and from 6.6 to 1.0 (per 1000 patient-days), respectively (P<0.0001, R2=0.86). No single technology, tool or procedure will eliminate healthcare-associated infections, but the addition of a ubiquitous facility-wide engineering solution at limited expense and with no alteration to patient, visitor or staff traffic or workflow patterns reduced infections by 45%. A similar impact was documented with the addition of comprehensive, restrictive, and labour- and material-intensive COVID-19 mitigation measures. To the authors' knowledge, this is the first direct comparison between traditional infection control, an engineering solution and COVID-19 mitigation measures.

Dry-fog decontamination of microbiological safety cabinets after activities with SARS-CoV-2: cycle development and process validation for dry fogging with peroxyacetic acid.

Background: Technical protection measures for laboratory activities involving biological agents include biological safety cabinets (BSC) that may be contaminated. In the case of diagnostic activities with SARS-CoV-2, this may also affect BSC that are operated at protection level 2; therefore, decontamination of all contaminated surfaces of the BSC may be required. In addition to fumigation with hydrogen peroxide (H2O2), dry fogging of H2O2-stabilized peroxyacetic acid (PAA) represents another alternative to fumigation with formalin. However, to prove their efficacy, these alternatives need to be validated for each model of BSC. Methods: The validation study was performed on 4 different BSCs of Class II A2 using the "Mini Dry Fog" system. Results: An aerosol concentration of 0.03% PAA and 0.15% H2O2 during a 30 min exposure was sufficient to inactivate SARS-CoV-2. Effective concentrations of 1.0% PAA and 5% H2O2 were required to decontaminate the custom-prepared biological indicators loaded with spores of G. stearothermophilus and deployed at 9 different positions in the BSC. Commercial spore carriers were easier to inactivate by a factor of 4, which corresponded to a reduction of 106 in all localizations. Conclusions: Dry fogging with PAA is an inexpensive, robust, and highly effective decontamination method for BSCs for enveloped viruses such as SARS-CoV-2. The good material compatibility, lack of a requirement for neutralization, low pH - which increases the range of efficacy compared to H2O2 fumigation - the significantly shorter processing time, and the lower costs argue in favor of this method.

Characteristics of SARS-CoV2 that may be useful for nanoparticle pulmonary drug delivery.

As a non-invasive method of local and systemic drug delivery, the administration of active pharmaceutical ingredients (APIs) via the pulmonary route represents an ideal approach for the therapeutic treatment of pulmonary diseases. The pulmonary route provides a number of advantages, including the rapid absorption which results from a high level of vascularisation over a large surface area and the successful avoidance of first-pass metabolism. Aerosolization of nanoparticles (NPs) is presently under extensive investigation and exhibits a high potential for targeted delivery of therapeutic agents for the treatment of a wide range of diseases. NPs need to possess specific characteristics to facilitate their transport along the pulmonary tract and appropriately overcome the barriers presented by the pulmonary system. The most challenging aspect of delivering NP-based drugs via the pulmonary route is developing colloidal systems with the optimal physicochemical parameters for inhalation. The physiochemical properties of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have been investigated as a template for the synthesis of NPs to assist in the formulation of virus-like particles (VLPs) for pharmaceutical delivery, vaccine production and diagnosis assays.

Direct and quantitative capture of viable bacteriophages from experimentally contaminated indoor air: A model for the study of airborne vertebrate viruses including SARS-CoV-2.

AIM: The air indoors has profound health implications as it can expose us to pathogens, allergens and particulates either directly or via contaminated surfaces. There is, therefore, an upsurge in marketing of air decontamination technologies, but with no proper validation of their claims. We addressed the gap through the construction and use of a versatile room-sized (25 m3 ) chamber to study airborne pathogen survival and inactivation. METHODS AND RESULTS: Here, we report on the quantitative recovery and detection of an enveloped (Phi6) and a non-enveloped bacteriophage (MS2). The two phages, respectively, acted as surrogates for airborne human pathogenic enveloped (e.g., influenza, Ebola and coronavirus SARS-CoV-2) and non-enveloped (e.g., norovirus) viruses from indoor air deposited directly on the lawns of their respective host bacteria using a programmable slit-to-agar air sampler. Using this technique, two different devices based on HEPA filtration and UV light were tested for their ability to decontaminate indoor air. This safe, relatively simple and inexpensive procedure augments the use of phages as surrogates for the study of airborne human and animal pathogenic viruses. CONCLUSIONS: This simple, safe and relatively inexpensive method of direct recovery and quantitative detection of viable airborne phage particles can greatly enhance their applicattion as surrogates for the study of vertebrate virus survival in indoor air and assessment of technologies for their decontamination. SIGNIFICANCE AND IMPACT OF THE STUDY: The safe, economical and simple technique reported here can be applied widely to investigate the role of indoor air for virus survival and transmission and also to assess the potential of air decontaminating technologies.

Aerosol Generation in Ear Canal and Air-Fluid Interface Suction.

OBJECTIVE: The identification of aerosol-generating procedures (AGPs) is important during the current SARS-CoV-2 pandemic due to aerosol-mediated virus transmission. Aerosol measurement during clinical procedures using particle counting may be confounded by variable natural background aerosol levels or limited by partial volume sampling. The study objective was to quantify any significant aerosol generated from simulated suction clearance procedures. STUDY DESIGN: Prospective quantification of aerosol generation during clinical suction simulation. SETTING: Clean chamber. METHODS: We created a clean environment for particle counting in a transparent neutralized polypropylene chamber. Air was passed through a HEPA 14 class filter to maintain a constant chamber inlet pressure. An optical particle counter was connected in line to the chamber exhaust vent to measure all of the vented particles. The chamber background count was 1 particle ≥0.3 µm per 15 minutes at a flow rate of 1 chamber air change per minute. We used this system to quantify very low aerosol counts generated from suction clearance of a silicone ear canal and at an open air-fluid interface. RESULTS: No clinically significant aerosol generation was found by particle counting of the whole chamber air volume during simulated suction procedures. CONCLUSION: Simulated ear suction clearance and air-fluid interface suction does not generate any significant aerosol. It appears likely that any aerosol potentially generated at the suction tube tip is entrained by incoming air flow. This is the first study to quantify aerosols generated by suction in a controlled environment; further research is required to determine its clinical implications.