Heat And Moisture Exchanger Research Articles

High Peak Inspiratory Pressures After a Change of Heat and Moisture Exchangers: A Case Series.

Elevated peak inspiratory pressures (PIPs) cause harm via hypoventilation, barotrauma, and hemodynamic instability. Heat and moisture exchangers (HMEs) are used during mechanical ventilation to prevent heat loss, dehydration of airway mucosa, and accumulation of dried secretions. Multiple reports detail sudden HME occlusions causing increased PIPs. We describe 4 cases of gradually increasing PIPs from progressive HME obstruction that occurred within 6 months of an institutional change to a newer model. HME obstruction should be considered when PIPs are elevated. Alternative heat and moisture preservation strategies should be contemplated, as HMEs increase airflow resistance and add another point of possible malfunction.

Development and validation of a 3D printed antiviral ventilator filter - a comparative study

BackgroundThe current coronavirus infectious disease 2019 (COVID-19) pandemic has caused unexpected pressure on medical supplies, interrupting supply chains and increasing prices. The supply of antiviral filters which form an essential part of the ventilator circuit have been affected by these issues. Three-dimensional (3D) printing may provide a solution to some of these issues.MethodsWe designed and tested 3D printed heat and moisture exchange (HME) and antiviral casing. For each casing we tested two different filter materials derived from a sediment water filter cartridge or 1.5-μm glass fiber filter paper. A polyurethane sponge was used for the HME. Each design was tested for circuit leak, circuit compliance, peak inspiratory pressure and casing integrity using methylene blue dye.ResultsWe designed, produced, and tested two different types of antiviral filters with six different internal configurations. Overall, we tested 10 modified filter designs and compared them with the original commercial filter. Except for the combination of 1.5-μm filter paper and 5 mm sponge peak inspiratory pressure and circuit compliance of the filters produced were within the operating limits of the ventilator. All In addition, all filters passed the dye test.ConclusionsOur filter may be of particular importance to those working in low middle-income countries unable to compete with stronger economies. Our design relies on products available outside the healthcare supply chain, much of which can be purchased in grocery stores, hardware stores, or industrial and academic institutions. We hope that these HMEs and viral filters may be beneficial to clinicians who face critical supply chain issues during the COVID-19 pandemic.

Humidicare – an implementation study of a novel HME safety device designed to prevent ventilator circuit occlusion due to inadvertent dual humidification

Mechanical ventilation bypasses the protective mechanisms of the upper respiratory tract which are designed to heat and humidify inspired air to 37 °C and 44 mg H2O/L respectively. Artificial humidification systems are therefore incorporated into ventilation circuits to condition cold and dry medical gases before they reach the lower respiratory tract and cause patient harm. Commonly either a heat and moisture exchanger (HME) or a heated humidifier (HH) are utilised for this purpose, however the inadvertent simultaneous use of both devices within the same circuit can cause critical airway occlusion within 24 h. The Humidicare HME (Medovate, Cambridge, UK) is a safety engineered temperature-dependent warning system designed to activate when inadvertently placed into a warm circuit containing a HH. This study aimed to determine the efficacy of the Humidicare HME warning system in simulated clinical conditions. The threshold temperature for activation of the device was determined in a digital incubator, and the device was tested for efficacy with a HH present or absent from the breathing circuit. The device performed reliably and activated rapidly when required across all simulations. The Humidicare HME warning system is a simple and unobtrusive device which can effectively alert the operator to the error of dual humidification.

Surgical Performance Is Not Negatively Impacted by Wearing a Commercial Full-Face Mask with Ad Hoc 3D-Printed Filter Connection as a Substitute for Personal Protective Equipment during the COVID-19 Pandemic: A Randomized Controlled Cross-Over Trial.

(1) Background: During the COVID-19 pandemic, shortages in the supply of personal protective equipment (PPE) have become apparent. The idea of using commonly available full-face diving (FFD) masks as a temporary solution was quickly spread across social media. However, it was unknown whether an FFD mask would considerably impair complex surgical tasks. Thus, we aimed to assess laparoscopic surgical performance while wearing an FFD mask as PPE. (2) Methods: In a randomized-controlled cross-over trial, 40 laparoscopically naive medical students performed laparoscopic procedures while wearing an FFD mask with ad hoc 3D-printed connections to heat and moisture exchange (HME) filters vs. wearing a common surgical face mask. The performance was evaluated using global and specific Objective Structured Assessment of Technical Skills (OSATS) checklists for suturing and cholecystectomy. (3) Results: For the laparoscopic cholecystectomy, both global OSATS scores and specific OSATS scores for the quality of procedure were similar (Group 1: 25 ± 4.3 and 45.7 ± 12.9, p = 0.485, vs. Group 2: 24.1 ± 3.7 and 43.3 ± 7.6, p = 0.485). For the laparoscopic suturing task, the FFD mask group needed similar times to the surgical mask group (3009 ± 1694 s vs. 2443 ± 949 s; p = 0.200). Some participants reported impaired verbal communication while wearing the FFD mask, as it muffled the sound of speech, as well as discomfort in breathing. (4) Conclusions: FFD masks do not affect the quality of laparoscopic surgical performance, despite being uncomfortable, and may therefore be used as a substitute for conventional PPE in times of shortage—i.e., the global COVID-19 pandemic.

A comparative evaluation of three common airway humidification methods for patients with severe traumatic brain injury

Airway humidification methods are commonly used in clinical practice, but no clear consensus exists on which particular method is best suited for specific clinical conditions. In this retrospective study, we carried out a quantitative evaluation of three methods commonly used for patients with severe traumatic brain injury (STBI). We recruited 150 patients who received airway humidification after tracheotomy. Subjects were divided into three groups according to the humidification method they received which included oxygen atomizer (OA) group, heat and moisture exchangers (HMEs) group, and heated humidifiers (HHs) group. Variables including phlegm viscosity, humidification effects, phlegm formation rates, daily sputum inhalation times, airway spasm, secondary lung infections, daily nursing load, and evaluation of nurse job satisfaction levels were documented. Results indicated that the OA tended to cause either insufficient or excessive humidification, whereas phlegm scab formation was significantly reduced in HHs. HMEs and HHs displayed equal humidification effects, and a similar daily sputum induction and consequent nursing load. Airway spasm was a frequent occurrence in OA. The severity, but not the infection ratio, of secondary infection decreased significantly in HHs by the 30th day. The OA significantly reduced nursing load, but demonstrated the worst humidification effects. Overall results suggested that the HHs is more suitable for airway nursing of STBI patients who are bedridden for extended periods.

Cost-effectiveness analysis of using the heat and moisture exchangers compared with alternative stoma covers in laryngectomy rehabilitation: US perspective.

This study aims to evaluate the cost-effectiveness of using heat and moisture exchangers (HMEs) vs alternative stoma covers (ASCs) following laryngectomy in the United States. A cost-effectiveness and budget impact analysis were conducted including uncertainty analyses using real-world survey data with pulmonary events and productivity loss. HME use was more effective and less costly compared with ASCs. Quality-adjusted life years were slightly higher for HME-users. Total costs per patient (lifetime) were $59 362 (HME) and $102 416 (ASC). Pulmonary events and productivity loss occurred more frequently in the ASC-users. Annual budget savings were up to $40 183 593. Costs per pulmonary event averted were $3770. HME utilization in laryngectomy patients was cost-effective. Reimbursement of HME devices is thus recommended. Utilities may be underestimated due to the generic utility instrument used and sample size. Therefore, we recommend development of a disease-specific utility tool to incorporate in future analyses.

The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance (R airflow) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow (Q) amplitude and R airflow, as indicated by a pressure drop (P Drop) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T0) and after 24 hr of moisture testing (T24) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T0 and T24). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.

Tracheostoma valves and their associated risks

Tracheostoma valves have proven to be very effective for voice restoration in patients with a tracheotomy or laryngectomy. Nevertheless, in recent years there have been a number of reports about life-threatening incidents with tracheostoma valves. An analysis of these incidents and the commercially available tracheostoma valves, their functions and limitations enables typical risk situations to be derived. The most reported incidents were caused by inadvertently filling the cuff of the tracheostomy tube while the tracheostoma valve was in place and by confusing a heat and moisture exchanger (HME) filter with a tracheostoma valve. These mistakes caused a complete obstruction of the expiratory airway leading to a barotrauma of the lungs with pneumothorax and asphyxia. Another typical risk in mechanically ventilated patients is insufficient monitoring during the use of the tracheostoma valve. Clear marking of tracheostoma valves and a specific training of hospital personnel with respect to the typical risks of tracheostoma valves could effectively reduce the associated dangers.

Noise Level and Comfort in Healthy Subjects Undergoing High-Flow Helmet Continuous Positive Airway Pressure.

The aim of this study was to assess the noisiness levels produced by different gas source systems, breathing circuits setup, and gas flow rates during continuous positive airway pressure (CPAP) delivered through helmet. This was a crossover design study. Ten healthy subjects received helmet CPAP at 5 cm H2O in random order with different gas flow rates (60 and 80 L/min), 3 diverse gas source systems (A: Venturi system, B: oxygen and air flowmeters, C: electronic Venturi system), and 3 different breathing circuit configurations. During every step of this study, a heat and moisture exchanger (HME) was placed on the helmet inlet gas port to measure the effects on noise production. Noise intensity level was recorded through a sound-level meter. Participants scored their noisiness perception on a visual analog scale. The noise level inside the helmet ranged between 76 ± 4 and 117 ± 1 Decibel A. The gas source and the gas flow rate always affected the noise level inside and outside the helmet (P < .001). The different "breathing circuit setup" did not change the noise levels inside the helmet (P = .244), but affected the noise level outside, especially when a Venturi system was used (P < .001). An HME filter placed at the junction between the inspiratory limb of the breathing circuit and the helmet significantly decreased the noise intensity inside the helmet (mean dBA without HME, 99.56 ± 13.30 vs 92.26 ± 10.72 with HME; P < .001) and outside (mean dBA without HME, 68.16 ± 12.05 vs 64.97 ± 12.17 with HME; P < .001). The perception of noise inside the helmet was lower when an HME filter was placed on the inspiratory inlet gas port (median, 6 [interquartile range, 4-7] vs 7 [5-8]; P < .001). When helmet CPAP is delivered through gas flow rates up to 50 L/min, an HME placed on the helmet inlet gas port should be used to reduce noise inside the helmet and to improve patients' comfort.

Improved portable measuring device for real-time humidity and temperature monitoring in intensive care unit

Real time monitoring of temperature and humidity of the air conditioned by Heat and Moisture Exchangers (HMEs) and delivered to patients in intensive care units (ICU) is highly demanded by physicians. As demonstrated by recent literature, only in vivo monitoring of HMEs performances with compact portable measuring systems suitable for ICU routines could provide reliable results. One of the main challenges for these devices is represented by the response time of the integrated temperature and humidity sensors. Long response times might introduce delays and thus make it impossible to follow the actual parameter variation in real time during each breath. In order to overcome this issue, innovative commercial ultra-fast sensors for temperature and humidity monitoring have been properly integrated and characterized in a portable wireless system for in vivo HME monitoring. Tests were performed in laboratory under static and dynamic settings. Response times at 36.8% of about 32 ms and 155 ms were obtained, respectively, for temperature and for humidity sensors. An improvement respect to available devices was thus obtained, achieving a proper monitoring of humidity variations up to 35 acts/minute with a maximum error of 5%. Considering the typical range of respiratory frequency monitored in the ICU, these results make the system suitable for real time evaluation of air conditioning during mechanical ventilation, combining the portability required for integration in the ICU routine with measurement accuracy.

Heat and moisture exchanger cassettes: Results of a quality/safety initiative to reduce postoperative mucus plugging after total laryngectomy.

Tracheal dryness is a concern after total laryngectomy due to the potential for mucus plugs (MP). This study compared heat and moisture exchanger (HME) cassettes to external tracheal humidification (ETH) surrounding MP events. A retrospective comparative cohort study comparing outcomes before/after implementation of a patient safety initiative utilizing HME during post laryngectomy hospitalization. The number of MP events were compared with a pre-implementation control group using ETH. Patient characteristics were analyzed for correlation with MP. The rate of MP was significantly lower in the HME group than ETH (0.13 and 0.38 per 10 inpatient days, respectively, P = .02). The proportion of patients with one or more MP events was also significantly reduced in the HME group (50% ETH and 11% HME, P = .01). Method of humidification was the only significant variable associated with MP on logistic regression modeling (P = .008). HMEs were superior to ETH for prevention of MP.

Tidal Volume Lowering by Instrumental Dead Space Reduction in Brain-Injured ARDS Patients: Effects on Respiratory Mechanics, Gas Exchange, and Cerebral Hemodynamics.

BackgroundLimiting tidal volume (VT), plateau pressure, and driving pressure is essential during the acute respiratory distress syndrome (ARDS), but may be challenging when brain injury coexists due to the risk of hypercapnia. Because lowering dead space enhances CO2 clearance, we conducted a study to determine whether and to what extent replacing heat and moisture exchangers (HME) with heated humidifiers (HH) facilitate safe VT lowering in brain-injured patients with ARDS.MethodsBrain-injured patients (head trauma or spontaneous cerebral hemorrhage with Glasgow Coma Scale at admission < 9) with mild and moderate ARDS received three ventilatory strategies in a sequential order during continuous paralysis: (1) HME with VT to obtain a PaCO2 within 30–35 mmHg (HME1); (2) HH with VT titrated to obtain the same PaCO2 (HH); and (3) HME1 settings resumed (HME2). Arterial blood gases, static and quasi-static respiratory mechanics, alveolar recruitment by multiple pressure–volume curves, intracranial pressure, cerebral perfusion pressure, mean arterial pressure, and mean flow velocity in the middle cerebral artery by transcranial Doppler were recorded. Dead space was measured and partitioned by volumetric capnography.ResultsEighteen brain-injured patients were studied: 7 (39%) had mild and 11 (61%) had moderate ARDS. At inclusion, median [interquartile range] PaO2/FiO2 was 173 [146–213] and median PEEP was 8 cmH2O [5–9]. HH allowed to reduce VT by 120 ml [95% CI: 98–144], VT/kg predicted body weight by 1.8 ml/kg [95% CI: 1.5–2.1], plateau pressure and driving pressure by 3.7 cmH2O [2.9–4.3], without affecting PaCO2, alveolar recruitment, and oxygenation. This was permitted by lower airway (− 84 ml [95% CI: − 79 to − 89]) and total dead space (− 86 ml [95% CI: − 73 to − 98]). Sixteen patients (89%) showed driving pressure equal or lower than 14 cmH2O while on HH, as compared to 7 (39%) and 8 (44%) during HME1 and HME2 (p < 0.001). No changes in mean arterial pressure, cerebral perfusion pressure, intracranial pressure, and middle cerebral artery mean flow velocity were documented during HH.ConclusionThe dead space reduction provided by HH allows to safely reduce VT without modifying PaCO2 nor cerebral perfusion. This permits to provide a wider proportion of brain-injured ARDS patients with less injurious ventilation.

The impact of a heat and moisture exchange mask on respiratory symptoms and airway response to exercise in asthma.

Respiratory symptoms, including cough, are prevalent in individuals with asthma when exercising. This study investigates whether a heat and moisture exchanger (HME) face mask is effective in modulating exercise-induced bronchoconstriction (EIB) and post-exercise cough in a cold, dry environment in individuals with asthma.Twenty-six participants diagnosed with asthma (20 males, 6 females) completed three cycling exercise challenges at 8°C and 24% relative humidity in a randomised order. Participants wore either an HME mask (MASK), sham mask (SHAM), or no mask (CONT). Following a 3-min warm-up, participants completed 6-min cycling at 80% peak power output. Before and after exercise, maximal flow-volume loops were recorded. Post-exercise cough was monitored with a Leicester Cough Monitor (LCM) for 24 h. Results were analysed using repeated-measures ANOVA and Friedman's tests and data were presented as the mean±sd or median (interquartile range (IQR)).Eleven participants failed to demonstrate EIB (i.e. >10% fall in forced expiratory volume in 1 s after exercise) and were removed from analysis. The percentage fall in forced expiratory volume in 1 s following exercise in CONT was greater than MASK (MASK: −6% (7%), SHAM: −11% (11%), CONT: −13% (9%); p<0.01). No difference was found between exercise in cough count per hour over the 24-h monitoring period or the number of coughs in the first hour after exercise.HME masks can attenuate EIB when exercising in cold, dry environments. The SHAM mask may not have been entirely inert, demonstrating the challenges of running randomised control trials utilising control and sham conditions.

Wet-Side Breath-Enhanced Jet Nebulization: Controlling Drug Delivery During Mechanical Ventilation.

The present study tested a novel nebulizer and circuit that use breath enhancement and breath actuation to minimize ventilator influences. The unique circuit design incorporates "wet-side" jet nebulization (the nebulizer connected to the humidifier outlet port) to prevent unpredictable aerosol losses with active humidification. The system was studied using several ventilator brands over a wide range of settings, with and without humidification. During treatment, a 2-position valve directed all ventilator flow to the nebulizer, providing breath enhancement during inspiration. Aerosol was generated by air 50 psi 3.5L/m triggered during inspiration by a pressure-sensitive circuit. Particles were captured on an inhaled mass filter. Testing was performed by using active humidification or bypassable valved heat and moisture exchanger (HME) over a range of breathing patterns, ventilator modes, and bias flows (0.5-5.0L/m). The nebulizer was charged with 6mL of radiolabeled saline solution. Mass balance was performed by using a gamma camera. Tidal volume was monitored by ventilator volume (exhaled VT) and test lung volume. The Mann-Whitney test was used. A total of 6mL was nebulized within 1 h. Inhaled mass (% neb charge): mean ± SD (all data) 31.1% ± 6.45; no. = 83. Small significant differences were seen with humidification for all modes (humidified 36.1% ± 5.60, no. = 26; bypassable valved HME 28.8% ± 5.51, no. = 57 [P < .001]), continuous mandatory ventilation modes [P < .001], and pressure support airway pressure release ventilation modes [P < .001]. Mass median aerodynamic diameter ranged from 1.04 to 1.34 μm. The VT was unaffected (exhaled VT -5.0 ± 12.9mL; P = .75) and test lung (test lung volume 25 ± 14.5 mL; P = .13). Bias flow and PEEP had no effect. Breath enhancement with breath actuation provided a predictable dose at any ventilator setting or type of humidification. Preservation of drug delivery during active humidification is a new finding, compared with previous studies. The use of wall gases and stand alone breath actuation standardizes conditions that drive the nebulizer independent of ventilator design. Wet-side nebulizer placement at the humidifier outletallows delivery without introducing aerosol into the humidification chamber.

Intervention to reduce carbapenem-resistant Acinetobacter baumannii in a neonatal intensive care unit.

To investigate the effects of environmental cleaning and the installation of heat and moisture exchangers (HMEs) to reduce neonatal carbapenem-resistant Acinetobacter baumannii (CRAB) sepsis and colonization as well as antimicrobial use. We conducted a 7-year, quasi-experimental study. All neonates admitted to a neonatal intensive care unit (NICU). We compared the trends for CRAB sepsis and colonization before (period 1, 2011-2013) and after (period 3, 2015-2017) a 12-month intervention period in 2014 (period 2) to incorporate a combination of HME use and sodium hypochlorite cleaning (5,000 ppm in the NICU and 500 ppm in the neonatal environment) using interrupted time series analysis with segmented regression. During the 7-year study period, 3,367 neonates were admitted to the NICU; the prevalence rates of CRAB sepsis and endotracheal CRAB colonization were 0.5 per 1,000 patient days, and 19.4 per 1,000 ventilator days. A comparison of period 1 to period 3 showed significant decreases in the percentages of both CRAB of A. baumannii sepsis (100% versus 11%) and endotracheal colonization (76% vs 52%) following the introduction of disposable HMEs and sodium hypochlorite cleaning (both P < .001). In period 3, compared with period 1, segmented regression analysis showed significant reductions in endotracheal CRAB colonization per 1,000 ventilator days (ie, change in level) and both carbapenem and colistin use (changes in both level and slope) (P < .001). Interventions featuring environmental cleaning and use of HMEs led to a sustainable reduction of CRAB colonization coupled with a reduction in broad-spectrum antimicrobial use in the NICU.

Heated Humidifier versus Heat-and-Moisture Exchanger During Positive Pressure Ventilation With a T-Piece Resuscitator in Rabbits.

There are many proven benefits of the use of conditioned gases in mechanically ventilated patients. In spite of this, its use in the delivery room is limited, perhaps because of known difficulties with heated humidifiers (HH); moreover, there is no evidence regarding the use of heat-and-moisture exchangers (HME) in a delivery room setting. We sought to asess the airway's absolute humidity level using three diferents strategies: HH, HME and unconditioned gases. We conducted an experimental study in 12 intubated rabbits ventilated with a T-piece resuscitator. Absolute humidity levels in inspired gases were measured at baseline and at 5, 10, 15, and 20 min while using HH, HME, or no conditioning method (ie, unconditioned). The animals were initially randomized to one of the 3 interventions, and each animal underwent the other methods with at least 24 h between each test. There were no differences in vital signs at baseline or at the end of the procedures. Mean absolute humidity at the end of the tests was 38.2 ± 1.7 g/m3 for HH, 28.9 ± 4.7 g/m3 for HME, and 13.9 ± 5.1 g/m3 for unconditioned gas (P = .003). During ventilation with a T-piece resuscitator, the absolute humidity was the highest with HH. The absolute humidity with HME was lower, but it was still significantly more than that with unconditioned gas. Therefore, the use of a T-piece resuscitator with HME could be a good alternative to HH given that positive-pressure ventilation is used ideally for short periods of time in the delivery room.

Effect of a heat and moisture exchanger on temperature and humidity of inhaled gas in isoflurane-anesthetized dogs

ObjectiveTo investigate the effects of a heat and moisture exchanger (HME) on the temperature and humidity of inhaled gas in isoflurane-anesthetized dogs. Study designProspective, interventional study. AnimalsA total of four experimental dogs and four client-owned dogs weighing 13.9 ± 7.4 kg (mean ± standard deviation). MethodsThe four experimental dogs were anesthetized on two occasions with and without an intact HME at least 1 week apart. The four client-owned dogs were anesthetized once only for a surgical procedure and assigned to the HME group or no-HME group in alternate order, resulting in six dogs for each group. All dogs were premedicated, anesthetized with propofol and intubated. The HME was connected to the endotracheal tube. Anesthesia was maintained with isoflurane. A digital thermo-hygrometer was placed between the endotracheal tube and HME. The temperature and relative humidity of the inhaled gas were measured every 5 minutes for 60 minutes and the absolute humidity was calculated at each time point. ResultsThe temperature and absolute humidity of the inhaled gas was significantly higher at 5–60 minutes after intubation in the HME group than in the no-HME group. Absolute humidity was maintained above 29 mg H2O L−1 in the HME group. No significant time-dependent effects on temperature, relative humidity or absolute humidity of the inhaled gas were observed. Conclusions and clinical relevanceThe temperature and absolute humidity of the inhaled gas were higher when an HME was used during isoflurane anesthesia in dogs. The use of an HME may reduce the risk of dehydration and dysfunction of the airway mucosal epithelium.

Safe Gynecological Laparoscopic Surgery during COVID Times.

Background:SARS-CoV-2 virus is largely transmitted via respiratory droplets and the highest transmission risks arise when undertaking aerosol generating procedures like laparoscopy. Most national societies had advised the urgent suspension of elective surgery with the focus shifting to emergency and cancer surgery only during this pandemic. However very little is known regarding the risks to the health care professionals undertaking emergency laparoscopic procedures.Aims and Objective:To demonstrate safety at laparoscopy by modifying the technique for safe management of patients during the COVID-19 pandemic.Design and Setting:This is an observational cohort study. This study was done at a tertiary care reference hospital for minimal access gynaecological surgery. Safety of 42 semi-urgent and emergency laparoscopic surgeries in patients was evaluated for a period of 5 months after taking informed written consent of patients to participate in the study.Materials and Methods:Use of double closed circuit laparoscopic suction evacuation and filtration systems with closed circuit anaesthesia with specialized Heat and Moisture Exchangers (HME) bacterial & viral (BV) filters to make laparoscopic surgery safe.Results:57.14% of the patients were 41 years or more. 47.6% presented either with menorrhagia, irregular vaginal bleeding or post-menopausal vaginal bleeding and 26.19 % patients were keen to conceive. In 50% patients, surgery was done in 60 minutes or less. Post-operatively, none of the patients had any complications and all were followed up for 14 days for COVID-19 infection. No staff, doctors or anaesthetist were detected COVID-19 positive during the follow up period. The limitation of the study was, that it was an observational study done in COVID-19 negative patients only.Conclusions:Safety at laparoscopy can be maintained when it is performed by an experienced surgeon who has full knowledge of safe laparoscopic techniques and performs it in the shortest time possible and with all due precautions.

Effects of a heat and moisture exchanger on respiratory function and symptoms post-cold air exercise.

PurposeExercise at temperatures below −15°C induces drying and cooling of lung airways which causes exercise‐induced bronchoconstriction (EIB) and respiratory symptoms, especially in winter sport athletes. The objective of this study was to evaluate whether a heat and moisture exchanger (HME) worn during intense cold air exercise improves lung function and reduces respiratory symptoms in healthy winter sport athletes.MethodsSeven active males and six active females (maximum oxygen uptake 61.9 ± 6.9 and 52.2 ± 5.3 mL/kg/min), all active or former winter sport athletes, completed running trials with and without HME in random order on 2 days in an environmental chamber (−20°C temperature, humidity 46.2%). Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory flow at 25%‐75% (FEF25%‐75%), and FEF at 50% (FEF50%) were measured pre‐ and post‐exercise (3, 6, 10, 15, and 20 minutes). Respiratory symptoms were reported after exercise.ResultsSignificant interaction effects were observed for FEV1 and FEF25%‐75%. Mean decrease of FVC (−5.9%, P ≤ .001) and FEV1 (−4.2%, P = .003) was largest 3 minutes post‐exercise without HME. There was an increase of FEV1, FEF25%‐75%, and FEF50% post‐exercise compared to pre‐exercise with HME. More respiratory symptoms overall were reported without HME (P = .046).ConclusionIntense cold air exercise likely causes transient acute bronchoconstriction and symptoms of cough in individuals participating in winter sports. However, this study finds that the application of an HME during intense cold air exercise improves lung function and reduces prevalence of EIB‐associated symptoms compared to unprotected intense cold air exercise.

Patient access to voice prostheses and heat and moisture exchangers: Factors influencing physician’s prescription and reimbursement in eight European countries

ObjectivesPatient access to the voice prosthesis and heat and moisture exchanger (HME) is not always guaranteed in Europe. Therefore, the aim of this qualitative study is to evaluate factors influencing physician's prescription and reimbursement of these devices in eight European countries, and to identify barriers of and facilitators to effective patient access. Materials and methodsIn this mixed methods study, we conducted a survey among stakeholders evaluating prescription (Part 1 of the survey), reimbursement (Part 2), and barriers of and facilitators to effective patient access (Part 3). Part 1 was completed by head and neck surgeons employed in France, Germany, the United Kingdom, Italy, Spain, Belgium, the Netherlands and Poland. Part 2 and 3 were completed by medical device company representatives in respective countries, followed by semi-structured interviews. ResultsBased on the survey, filled in by 36 surgeons, all prescribed the voice prosthesis. Four surgeons didn't prescribe the HME in Italy and Poland due to lack of both reimbursement and experience/training, and feeling uncomfortable with device use. Most restrictive factors (e.g. increased workload, insufficient staff) occurred in countries with decentralized healthcare systems including Spain and Italy. ConclusionNon-HME-usage was influenced by economical and physician-related factors. Restrictive factors were related to limited regional device reimbursement and provision. Nationwide reimbursement, guideline implementation, support for physicians by training/education and providing a rehabilitation team will increase device use.