Humidification Devices Research Articles

Experimental study on the performance of various porous water-absorbing fiber materials for indoor humidification

To increase the relative humidity in heating rooms in winter, a new humidification method is proposed. The capillary water absorption performance of porous fiber materials is utilized to compose a bottom water-absorbing component, and the spray device of the traditional direct evaporative cooling system is eliminated, which can be used for miniaturized heating humidification devices. To compare the heating and humidification performance of various fiber materials, an experimental system was designed and constructed with fiber materials arranged in parallel as humidification components. The experimental materials include nonwoven fabric (Sample A), polyester fiber (Sample B) and fiber cotton (Sample C). The experimentally obtained temperature drop is lower than the conventional evaporative cooling system, and the relative humidity enhancement is between 6 % and 15 %. Sample B had a maximum temperature drop of 6.83 °C, a maximum relative humidity increment of 14.07 %, a maximum humidification capacity of 272.4 g/h, and a maximum humidification capacity per unit area of material of 972.86 g/(m2·h). The maximum humidification capacity of Sample B was 13.8 % higher than that of Sample A and 18.5 % higher than that of Sample C. The cooling energy density of the three samples was only within 330 J/m3 under all working conditions. Applying sample B to the fan coil unit increased the relative humidity by 33.8 % with only 0.3 °C temperature drop, providing humidification while heating the indoor air. This paper provides a theoretical basis for a fiber material humidification, which to some extent can meet the heating and humidification integration in winter.

Ultrasonic Levitation for Airway Humidification.

This study employs the transmitter part of an ultrasonic proximity sensor to generate a powerful ultrasonic field for medical humidification. This field is created using an arrangement of small ultrasonic transmitter transducers configured in an acoustic levitator-style setup. As droplets pass through this ultrasonic field, they undergo disintegration, leading to an accelerated evaporation process. The research findings highlight a significant change in droplet size distribution due to ultrasonics, resulting in a notable increase in the rate of evaporation. As a result, this study presents a conceptual framework for reimagining humidification devices for lung therapeutic purposes through the utilization of simple sensor technology.

Application of the integrated airway humidification device enhances the humidification effect of the rabbit tracheotomy model.

Long-term mechanical ventilation after tracheotomy is a common treatment in intensive care unit patients. This study investigated the differences among the effects of different wetting states on the airway, lung, and serum inflammatory factors. New Zealand rabbits (n = 36) were selected to construct tracheotomy models and then divided into four groups: Model, Mask, YTH, and Sham groups. Lung tissue dry/wet ratio was used to evaluate the humidification effect; cytokines, including tumor necrosis factor-α, interleukin (IL)-6, IL-8, and IL-10, were used to evaluate the inflammatory response; hematoxylin and eosin staining was used to evaluate the histopathology. Post hoc analysis based on the Dunnett t-test was applied. A self-developed integrated wetting device could increase the utilization of wetting solution, enhance the effect of wetting to protect tissue integrity, and suppress airway inflammation, reducing the expression of pro-inflammatory factors while promoting the expression of anti-inflammatory factor IL-10 to inhibit the inflammatory response, compared to other methods. The integrated humidification device provided a new method for clinical nursing practice, improving clinical efficiency and reducing nursing workload. Further clinical trials are required to test its effectiveness and safety in the clinic.

Experimental investigation on the thermal and flow performance of a thermodynamically-balanced packed bed humidification system

In this paper, a packed bed humidification system filled with corrugated wire mesh was experimentally investigated to obtain a better humidification performance. To thermodynamically balance the simultaneous heat and mass transfer process, multiple water injection bypasses were fabricated at different packing heights based on the entropy generation minimization method. In addition to the inlet water temperature, the influences of the liquid–gas ratio and injection ratio on the humidification capacity, energy effectiveness, and pressure drop were respectively studied and discussed. The experimental and comparison results demonstrated that the established humidification device was robust and superior. It was summarized that raising the number of injections can significantly elevate the humidification capacity, and synchronously magnify the pressure drop for all the cases, while the effectiveness behaved a reverse trend. Additionally, a higher value of the inlet water temperature could increase the humidification capacity and effectiveness, as well as the pressure drop. And, an elevation amplitude of the humidification capacity emerged as 35.51% for the double water injections with a maximum value of 1.48 × 10−2 kgs−1 once the liquid–gas ratio increased from 1 to 1.36, while the value was 39.13% as the injection ratio raised from 0.33 to 0.7. Furthermore, it was illustrated that increasing the mass flow rate of the liquid will reduce the effectiveness when the heat capacity rate ratio is larger than 1, and the effectiveness can reach 0.97 at Twi = 70 °C. In the process of thermodynamic balancing, the increase in the pressure drop of humid air should receive more attention for the designer and researcher related to the packed bed humidifier.

Design of a Closed Piggery Environmental Monitoring and Control System Based on a Track Inspection Robot

To improve environmental quality in enclosed piggeries, a monitoring and control system was designed based on a track inspection robot. The system includes a track mobile monitoring platform, an environmental control system, and a monitor terminal. The track mobile monitoring platform consists of three main components: a single-track motion device, a main box containing electronic components, and an environmental sampling device. It is capable of detecting various environmental parameters such as temperature, humidity, NH3 concentration, CO2 concentration, light intensity, H2S concentration, dust concentration, and wind speed at different heights below the track. Additionally, it can control on-site environmental control equipment such as lighting systems, ventilation systems, temperature control systems, and manure cleaning systems. The networked terminal devices enable real-time monitoring of field equipment operating status. An adaptive fuzzy PID control algorithm is embedded in the system to regulate the temperature of the piggery. Field tests conducted on a closed nursery piggery revealed that the system effectively controlled the maximum temperature range within 2 °C. The concentrations of CO2, NH3, and PM2.5 were maintained at a maximum of 1092 mg∙m−3, 16.8 mg∙m−3, and 35 μg∙m−3, respectively. The light intensity ranged from 51 to 57 Lux, while the wind speed remained stable at approximately 0.35 m∙s−1. The H2S concentration was significantly lower than the standard value, and the lowest relative humidity recorded was 18% RH at high temperatures. Regular humidification is required in closed piggeries and other breeding places when the system does not trigger the wet curtain humidification and cooling function, as the relative humidity is lower than the standard value. By controlling the temperature, the system combined with a humidification device can meet environmental requirements. The control method is simple and effective, with a wide range of applications, and holds great potential in the field of agricultural environmental control.

The optimized design of air heat metering in the fan coil performance test system

With the improvement of the level of economic development and the quality of people’s living standards, people’s requirements for air quality also increase. The demand for airconditioning equipment to regulate indoor air quality is also increasing year by year. The resulting high energy consumption and energy waste problems can not be ignored. All we can do is optimize the equipment on an existing basis to minimize energy consumption. In this paper, the automatic humidification device of the wet bulb thermometer is designed to optimize the thermal performance test system of the fan coil unit, improve the quality of the fan coil, and ultimately achieve the goal of reducing energy consumption.

Impact of Airway Humidification Strategy in Mechanically Ventilated COVID-19 Patients.

Humidification of inspiratory gases is mandatory in all mechanically ventilated patients in ICUs, either with heated humidifiers (HHs) or with heat and moisture exchangers (HMEs). In patients with COVID-19, the choice of the humidification device may have relevant impact on patients' management as demonstrated in recent studies. We reported data from 2 ICUs using either HME or HH. Data from patients with COVID-19 requiring invasive mechanical ventilation during the first wave in 2 ICUs in Québec City were reviewed. In one ICU, HMEs were used, whereas heated-wire HHs were used in the other ICU. We compared ventilator settings and arterial blood gases at day one after adjustment of ventilator settings. Episodes of endotracheal tube occlusions (ETOs) or subocclusions and a strategy to limit the risk of under-humidification were reported. On a bench test, we measured humidity with psychrometry with HH at different ambient temperature and evaluated the relation with heater plate temperature. We reported data from 20 subjects positive for SARS-Cov-2, including 6 in the ICU using HME and 14 in the ICU using HH. In the HME group, PaCO2 was higher (48 vs 42 mm Hg) despite higher minute ventilation (171 vs 145 mL/kg/min predicted body weight [PBW]). We also reported 3 ETOs occurring in the ICU using HH. The hygrometric bench study reported a strong correlation between heater plate temperatures of the HH and humidity delivered. After implementation of measures to avoid under-humidification, including heater plate temperature monitoring, no more ETOs occurred. The choice of the humidification device used in subjects with COVID-19 had a relevant impact on ventilation efficiency (increased CO2 removal with lower dead space) and on complications related to low humidity, including ETOs that may be present with heated-wire HHs when used with high ambient temperatures.

Aerosol particle concentrations with different oxygen devices and interfaces for spontaneous breathing patients with tracheostomy: a randomised crossover trial.

For stable spontaneously breathing tracheostomy patients with uncuffed airways, different humidification devices and interfaces did not generate clinically significant differences of aerosol particle concentrations https://bit.ly/2Y1HSO2

Programmed Multi-Level Ventilation: A Strategy for Ventilating Non-Homogenous Lungs.

Mechanical ventilation (MV) has been an integral method used in ICU care for decades. MV is typically viewed as a life-supporting intervention. However, it can also contribute to lung injury through stress and strain, as evidenced by ventilator-induced lung injury (VILI), even in previously healthy lungs. The negative impact may be worsened when significant lung non-homogeneity is present, eg. ALI and ARDS. Protective lung strategies to minimize VILI are to use low tidal volumes (Vt 4–6 mL/kg/PBW), plateau pressures (Pplat) <30 cmH2O and relatively high positive end-expiratory pressures (PEEP). Yet, use of constantly high PEEP levels is well recognized to result in hemodynamic compromise of the right ventricle, increased stress and strain through high mechanical energy impact on the lung and overdistension of relatively healthy lung tissue. Taking these issues into consideration, a different approach to mechanical ventilation was developed specifically for patients with non-homogeneity. This review focuses on a feature called programmed multi-level ventilation (PMLV). It is not a ventilation mode per se, but rather a form of extension that adjusts and modifies any ventilation mode (eg PCV,PSV, VCV, SIMV, etc.). PMLV is based on measured time constants (Tau) of the whole respiratory system, including artificial airways, breathing circuits, humidification devices and mechanical ventilator. Using a physiology-based approach presents a method to ventilate non-homogenous lungs through cyclic changes of different PEEP levels; recruitment takes place in lung areas with long time constants but protects relatively healthy lung areas from overdistension thus minimizing excessive mechanical power to the lung tissue.

Experimental and numerical investigation of frost formation on an array of square fins under natural convection condition

The numerical and experimental processes of frost formation on square-finned tubes in natural convection are investigated in the current study. The frost growth survey on these types of finned tubes is beneficial and necessary to understand heat and humidity control phenomena due to low operating temperature. By using cooling, heating, and humidification devices, controlled conditions such as relative humidity between 50% to 70%, ambient air temperature between 20 °C to 30 °C, and an average refrigerant temperature between −20 °C to −10 °C are changed. The results include frost thickness, density, and heat transfer consequences under various ambient temperature conditions, average refrigerant temperature, and humidity. Based on empirical measurements, the frost accumulated on top of the fin is higher than the bottom, and frost is formed only on the fins' edge and blocks the flow path and short space between the fins. The computational fluid dynamics method is applied to predict the flow field and frost growth on the fins. Comparison between numerical results and experimental data shows that the current numerical method can be utilized more effectively to find out the frost behavior. According to the measurements, correlations are presented for frost growth.

Longitudinal changes in compliance, oxygenation and ventilatory ratio in COVID-19\xa0versus\xa0non-COVID-19 pulmonary acute respiratory distress syndrome

BackgroundDifferences in physiology of ARDS have been described between COVID-19 and non-COVID-19 patients. This study aimed to compare initial values and longitudinal changes in respiratory system compliance (CRS), oxygenation parameters and ventilatory ratio (VR) in patients with COVID-19 and non-COVID-19 pulmonary ARDS matched on oxygenation.Methods135 patients with COVID-19 ARDS from two centers were included in a physiological study; 767 non-COVID-19 ARDS from a clinical trial were used for the purpose of at least 1:2 matching. A propensity-matching was based on age, severity score, oxygenation, positive end-expiratory pressure (PEEP) and pulmonary cause of ARDS and allowed to include 112 COVID-19 and 198 non-COVID pulmonary ARDS.ResultsThe two groups were similar on initial oxygenation. COVID-19 patients had a higher body mass index, higher CRS at day 1 (median [IQR], 35 [28–44] vs 32 [26–38] ml cmH2O−1, p = 0.037). At day 1, CRS was correlated with oxygenation only in non-COVID-19 patients; 61.6% and 68.2% of COVID-19 and non-COVID-19 pulmonary ARDS were still ventilated at day 7 (p = 0.241). Oxygenation became lower in COVID-19 than in non-COVID-19 patients at days 3 and 7, while CRS became similar. VR was lower at day 1 in COVID-19 than in non-COVID-19 patients but increased from day 1 to 7 only in COVID-19 patients. VR was higher at days 1, 3 and 7 in the COVID-19 patients ventilated using heat and moisture exchangers compared to heated humidifiers. After adjustment on PaO2/FiO2, PEEP and humidification device, CRS and VR were found not different between COVID-19 and non-COVID-19 patients at day 7. Day-28 mortality did not differ between COVID-19 and non-COVID-19 patients (25.9% and 23.7%, respectively, p = 0.666).ConclusionsFor a similar initial oxygenation, COVID-19 ARDS initially differs from classical ARDS by a higher CRS, dissociated from oxygenation. CRS become similar for patients remaining on mechanical ventilation during the first week of evolution, but oxygenation becomes lower in COVID-19 patients.Trial registration: clinicaltrials.gov NCT04385004

Performance analysis of desiccant wheels assisted fresh air humidifiers in winter using natural gas boilers: Applied in cold and dry climate regions

A fresh air handling unit is proposed for space humidification in winter for buildings located in cold and dry climate regions. The air handling unit has three-stage desiccant wheels to transfer moisture from dehumidification air (A deh ) to humidification air (A hum ), both of which are from outdoor, and heat from boilers is used to drive this process. Humidification performances of this device were discussed when ambient humidity ratio was from 1 to 4.5 g kg −1 and corresponding operating strategies under different ambient conditions were proposed to keep the supply humidity ratio in the range of 5.1–5.5 g kg −1 . Then, effective heating systems, including air side heat recovery and step utilization of heat from low-grade waste heat, were investigated. Humidification efficiency ( η sys ) of systems without heat recovery ranges from 0.24 to 0.9. With heat recovery at the air side, which is called improved system I, η sys was enhanced to 0.4–1.2. Water circulation layout was redesigned to realize step utilization of heat. Return water temperature from humidification devices could be reduced, and η sys can be obviously enhanced when low-grade waste heat sources are available. When air source heat pumps are used to preheat the return water, from Case A to Case H, primary energy efficiency can be improved by 5.8–26.1% as compared with the improved system I.

The addition of a humidifier device to a circuit and its impact on home ventilator performance: a bench study

Introduction and objectivesHumidification and non-invasive ventilation are frequently used together, despite the lack of precise recommendations regarding this practice. We aimed to analyse the impact of active external and built-in humidifiers on the performance of home ventilators, focusing on their pressurization efficacy and their behaviour under different inspiratory efforts. MethodsWe designed a bench study of a lung simulator programmed to emulate mechanical conditions similar to those experienced by real respiratory patients and to simulate three different levels of inspiratory effort: five different commonly used home NIV devices and active humidifiers attached to the latter (internal or “built-in”) or to the circuit (external). To test ventilator pressurization under different humidification and effort settings, pressure-time products in the first 300ms and 500ms of the respiratory cycle were calculated in the 45 situations simulated. Inferential statistical analysis was performed. ResultsA significant reduction of PTP 300 and PTP 500 was observed with the external humidifier in three of the devices. The same pattern was noted for another device with an internal humidifier, and only one device showed no significant changes. This impact on pressurization was commonly higher under high inspiratory effort. ConclusionsThese results indicate the need to monitor pressure changes in the use of external humidification devices in some home NIV ventilators.

Pressure modification or humidification for improving usage of continuous positive airway pressure machines in adults with obstructive sleep apnoea.

Pressure modification or humidification for improving usage of continuous positive airway pressure machines in adults with obstructive sleep apnoea.

Network meta-analysis of airway humidification in patients with non-mechanical ventilation after domestic gastrectomy

Objective To evaluate the therapeutic effects of various airway humidification methods to prevent pulmonary infection in non-mechanical ventilation patients by network meta-analysis. Methods The Pubmed, Embase, Web of Science, Wanfang data, and CNKI databases were searched and a randomized controlled trial (RCT) was developed for the method of humidification in non-mechanical ventilation patients after domestic air-surgery. The staff independently screened the literature, extracted the data, and used the stata14.0 software for network meta-analysis. Results In the 3 342 articles, 25 of them were included in the Meta-analysis, involving 6 methods of airway humidification. The order of effectiveness: first place in artificial nose, second in venturi humidification device, third in continuous atomization, Intermittent atomization ranked fourth, continued to drop into the fifth place, intermittently dropped into the sixth position of humidification. Conclusion The effectiveness of artificial nose device and venturi humidification device has been gradually recognized by domestic counterparts. Meta analysis shows that it is effective in preventing lung infection and worth promoting. Key words: Tracheotomy; Airway humidification; Non-mechanical ventilation; Artificial nose; venturi; Network Meta-analysis

A feasibility and efficacy trial of a hand-held humidification device in patients undergoing radiotherapy for head and neck cancer

This study aimed to evaluate the effects of warm-mist humidification during and after head and neck radiation therapy (HN RT) on quality of life (QOL), as measured by the M. D. Anderson Symptom Inventory-Head and Neck (MDASI-HN) HN score. A secondary aim was to compare QOL among compliers (≥60% of protocol-recommended usage) versus non-compliers. Twenty patients self-administered a hand-held, self-sterilizing humidification device for a recommended time of at least 15min twice daily for 12weeks. Patients completed the MDASI-HN instrument at RT start, after 6weeks, and after 12weeks. Compliance was reported weekly. The average HN score at baseline was 1.7 (SD=1.8) and increased to 6.0 (SD=1.6) after 6weeks; this increase was much higher than anticipated and the primary endpoint could not be reached. However, compliers had an average of nearly two less HN symptoms (-1.8, 95% CI -4 to 0.2; p=0.08) than non-compliers at 6weeks and fewer symptoms at 12weeks as well (-0.9, 95% CI -2.9 to 1.2; p=0.39). The most common terms patients used to describe humidification were "helpful" and "soothing." Compliance with humidification during RT was associated with fewer reported HN symptoms and a strong trend to better QOL. Improvements were seen from compliance with occasional required use of a portable, inexpensive device. Our findings support continued efforts to reduce barriers to humidification, as an intervention that should be considered for standard HN RT clinical practice.

An investigation into the prevalence of sleep disturbances in primary Sjögren’s syndrome: a systematic review of the literature

Objectives. To identify whether sleep disturbances are more prevalent in primary SS (pSS) patients compared with the general population and to recognize which specific sleep symptoms are particularly problematic in this population. Methods. Electronic searches of the literature were conducted in PubMed, Medline (Ovid), Embase (Ovid), PsychINFO (Ovid) and Web of Science and the search strategy registered a priori. Titles and abstracts were reviewed by two authors independently against a set of prespecified inclusion/exclusion criteria, reference lists were examined and a narrative synthesis of the included articles was conducted. Results. Eight whole-text papers containing nine separate studies met the inclusion criteria and were included in the narrative analysis. Few of these studies met all of the quality assessment criteria. The studies used a range of self-reported measures and objective measures, including polysomnography. Mixed evidence was obtained for some of the individual sleep outcomes, but overall compared with controls, pSS patients reported greater subjective sleep disturbances and daytime somnolence and demonstrated more night awakenings and pre-existing obstructive sleep apnoea. Conclusions. A range of sleep disturbances are commonly reported in pSS patients. Further polysomnography studies are recommended to confirm the increased prevalence of night awakenings and obstructive sleep apnoea in this patient group. pSS patients with excessive daytime somnolence should be screened for co-morbid sleep disorders and treated appropriately. Interventions targeted at sleep difficulties in pSS, such as cognitive behavioural therapy for insomnia and nocturnal humidification devices, have the potential to improve quality of life in this patient group and warrant further investigation.

Effect of microdose apparatus infusionis and transfusion alarm device on the water control of ;humidification device

Objective To explore the application of microdose apparatus infusionis in the process of water injection in the ventilator humidification device in order to strengthen the uniform temperature and moisture in patients with mechanical ventilation and improve the safety management of ventilator humidification device . Methods Eighty-three patients with mechanical ventilation were divided into the experimental group and the control group according to the semi random envelope .The experimental group received the constant water injection through the microdose apparatus infusions and transfusion alarm device , and the control group received the intermittent water injection through the normal infusion .The time of water injection , the temperature of end inhalation in patients after water injection , the elevation time of water temperature and sticky sputum were compared between the two groups.Results The time of water injection was （2.40 ±0.40） min/d in the experimental group, and was significantly lower than （13.24 ±11.03） min/d in the control group, and the difference was statistically significant （t =6.3658, P <0.01）.The temperature of inspired gas after water injection was （36.79 ±1.56）℃ in the experimental group, and was significantly higher than （24.29 ± 1.60） ℃in the control group, and the difference was statistically significant （t=36.038 2, P<0.01）.The sticky sputum was significantly reduced the third day after mechanical ventilation .Conclusions The microdose apparatus infusions and transfusion alarm device can keep on water injection in the humidification device , improve the accuracy of the humidifying water control , make the airway constant temperature humidification in patients, make up the alarm defect of humidification device , ensure the safety of humidification in patients , and reduce the workload of nurses . Key words: Microdose apparatus infusions; Airway humidification; Transfusion alarm device; Constant temperature

Perioperative hypothermia during surgery: is warming humidification a complete solution?

Hypothermia is a common complication in postoperative patients with well-known effects on hospital outcome [1]. Patients undergoing shoulder arthroscopy surgery in some cases develop different grades of perioperative hypothermia as a secondary effect of cold shoulder irrigation. Additionally, sedation and invasive mechanical ventilation aggravate this state. However, published studies regarding rational pathways to hypothermia during arthroscopic surgery suggest that other mechanisms could be influencing the loss, such as dry gases. Commonly, humidification devices, referred to as heat and moisture exchangers or humidified and electrically heated circuits (HHC), are used to - indirectly - control core body temperature (CBT), but this issue remains controversial when operating under invasive mechanical ventilation, and the efficacy remains unclear [1]. Jo et al. [2] described the effects of two humidification devices during arthroscopic shoulder surgery; the working hypothesis was that active warming and humidification of inspired gases may influence the decrease in CBT in arthroscopic shoulder surgery. The authors analyzed two devices, a conventional respiratory circuit (control group) and heating using a HHC (heated group). The major findings were significant temperature differences in CBT during two periods, immediately after anesthesia induction (30 min), and then in the HHC group, CBT was maintained better from 75 to 120 min after anesthesia induction. This original study makes a considerable contribution and has practical, clinical implications. However, other pathways may also explain the results and should be taken into account by the authors. First, a key aspect to consider is that the hypothermia reported could depend, in part, on lung function and mechanical ventilation interactions during arthroscopic surgery. Although the authors enrolled patients without previous lung disease, they did not provide complete information regarding the mechanical ventilation parameters. Briefly, these interactions depend mainly on the total flow rate during general anesthesia. Some studies reported that with a total flow rate of 2 L/min for 2 h, a humidifier might not be necessary, while with a total flow of 4 L/min, it could be useful to maintain inspired gas humidity [3]. A secondary contributing factor is minute volume (MV) during surgery, especially if we consider the MV upper limit to be 7 L/min [4]. These ventilator parameters are unknown and are issues. Second, the authors use a critical (after 75 min) to compare differences between the groups. However, this period was not fully justified by the authors and others have used a greater time period, of 14-h duration, to observe differences in humidification and BCT [5]. It is important to know whether the parameters of the mechanical ventilation and surgical procedure were stable during this period to exclude these factors. In this case, it seems more reasonable that differences between the two groups were associated with modifications in lung humidification function and reduced water loss from the airways because of the HHC. These aspects are essential for a proper analysis. Further large prospective clinical trials are needed to determine the interactions of humidification devices during arthroscopic surgery to avoid a hypothermic state, focusing on high-risk surgical patients and patient-mechanical ventilator interactions.

Humidification during mechanical ventilation in the adult patient.

Humidification of inhaled gases has been standard of care in mechanical ventilation for a long period of time. More than a century ago, a variety of reports described important airway damage by applying dry gases during artificial ventilation. Consequently, respiratory care providers have been utilizing external humidifiers to compensate for the lack of natural humidification mechanisms when the upper airway is bypassed. Particularly, active and passive humidification devices have rapidly evolved. Sophisticated systems composed of reservoirs, wires, heating devices, and other elements have become part of our usual armamentarium in the intensive care unit. Therefore, basic knowledge of the mechanisms of action of each of these devices, as well as their advantages and disadvantages, becomes a necessity for the respiratory care and intensive care practitioner. In this paper, we review current methods of airway humidification during invasive mechanical ventilation of adult patients. We describe a variety of devices and describe the eventual applications according to specific clinical conditions.