Steady optimistic airway strain (CPAP) remedy is a typical remedy for sleep apnea, a situation characterised by pauses in respiration throughout sleep. A core part of this remedy includes a tool that delivers pressurized air by a masks, guaranteeing constant airflow and stopping airway collapse. One frequent concern amongst potential customers, and typically a problem for his or her companions, pertains to the sound emitted by these gadgets.
The noise stage generated by a CPAP machine can considerably impression the standard of sleep for each the person and anybody sharing their sleeping house. Addressing this potential challenge is essential for profitable remedy adherence. Producers have made important developments in lowering noise ranges, producing machines quieter than many widespread family home equipment. Understanding the sources of this sound, such because the motor, airflow, and masks leakage, can empower customers to pick acceptable gear and reduce noise disruption. Traditionally, older fashions had been typically perceived as loud, contributing to remedy discontinuation. Trendy designs prioritize quieter operation, bettering affected person consolation and general therapeutic effectiveness.
The next sections will discover varied elements of CPAP sound ranges, together with components influencing perceived loudness, methods for minimizing noise, and an outline of present quiet CPAP expertise. Moreover, assets for troubleshooting noise points and looking for skilled steerage will likely be supplied.
1. Machine Sort
CPAP machine expertise varies, immediately influencing noise output. Totally different producers make the most of distinct motor designs and inside elements, impacting operational sound ranges. Some machines function superior noise-reduction expertise, similar to brushless motors and sound-dampening supplies. Older fashions or these missing these options could produce increased decibel ranges. Deciding on a machine particularly engineered for quiet operation can considerably affect the person expertise and promote remedy adherence.
Think about, for instance, the distinction between a regular fixed-pressure CPAP machine and an auto-adjusting CPAP (APAP) machine. Whereas each ship pressurized air, APAP machines alter strain based mostly on respiration wants. This fluctuation in strain can result in variations in sound output, doubtlessly making a extra noticeable sound profile in comparison with a fixed-pressure machine’s constant sound. Moreover, journey CPAP machines, designed for portability and compactness, may prioritize measurement and weight over sound discount, leading to doubtlessly increased noise ranges.
Understanding the connection between machine kind and noise output empowers knowledgeable decision-making. Prioritizing quiet operation throughout machine choice contributes to a extra optimistic remedy expertise. Consulting with a sleep specialist or respiratory therapist supplies customized steerage, guaranteeing acceptable machine choice based mostly on particular person wants and preferences. This proactive strategy enhances remedy success by mitigating noise-related disruptions.
2. Airflow Stress
Airflow strain, a cornerstone of CPAP remedy, performs a major function within the sound produced by the machine. Greater strain settings, required for some people to take care of open airways, typically correlate with elevated noise output. This stems from the better drive required to propel air at increased pressures, producing extra audible turbulence inside the machine and masks. Consequently, people requiring increased strain settings may understand their CPAP machines as louder. Conversely, decrease strain settings, typically ample for milder sleep apnea, sometimes end in quieter operation. For example, a strain of 10 cm H2O will seemingly produce much less noise than a strain of 15 cm H2O.
The connection between airflow strain and sound is additional influenced by different components, similar to masks kind and match. A poorly becoming masks, even at decrease pressures, can create leaks, producing whistling or hissing sounds. These leaks disrupt the meant airflow path, including to the general noise notion. Conversely, a well-fitted masks, even at increased pressures, can reduce extraneous noise by guaranteeing a {smooth} and managed airflow. Due to this fact, reaching an optimum masks match is essential for lowering noise whatever the prescribed strain setting. Common evaluation of masks match and potential leaks is crucial for sustaining each remedy effectiveness and minimizing noise disruption.
Understanding the interaction between airflow strain, masks match, and ensuing sound ranges permits for proactive administration of CPAP noise. Whereas strain settings are decided by particular person wants and prescribed by healthcare professionals, optimizing masks match supplies a controllable factor for noise discount. Recurrently checking for leaks and looking for skilled steerage for masks becoming ensures efficient remedy with minimized noise impression, selling higher sleep high quality for each the person and their sleeping associate.
3. Masks Design
Masks design considerably influences CPAP remedy sound ranges. Totally different masks typesnasal pillows, nasal masks, and full-face masksexhibit various noise profiles because of their development and airflow dynamics. Nasal pillow masks, inserting immediately into the nostrils, typically produce much less noise because of minimal air resistance. Nasal masks, protecting the nostril, can generate barely extra noise because of the bigger floor space and potential for air leaks across the nostril bridge. Full-face masks, encompassing each the nostril and mouth, could produce essentially the most noise because of their measurement and the better quantity of air required to take care of strain. For instance, a nasal pillow masks with vents designed for quieter exhalation could also be perceived as much less disruptive than a full-face masks with fewer venting choices.
Past the fundamental masks kind, particular design options additional impression noise ranges. Vents, accountable for exhaling carbon dioxide, contribute considerably to perceived noise. Smaller vents, whereas efficient for air change, can generate higher-pitched sounds because of elevated air velocity. Bigger, subtle vents typically cut back noise by permitting air to flee extra progressively. Moreover, the fabric and development of the masks cushion affect noise. Softer, extra pliable supplies could take up some sound vibrations, whereas firmer supplies may replicate sound, doubtlessly growing perceived loudness. The general design, together with the headgear and its connection to the masks body, additionally performs a task. A safe, well-adjusted headgear minimizes masks motion and reduces the probability of leaks, thus minimizing noise related to escaping air.
Cautious consideration of masks design options is crucial for minimizing noise and optimizing remedy consolation. Deciding on a masks based mostly on particular person wants, anatomical options, and noise preferences considerably impacts remedy adherence. Consulting with a sleep specialist or respiratory therapist facilitates knowledgeable decision-making relating to masks choice and ensures correct becoming, additional lowering noise and maximizing therapeutic effectiveness.
4. Masks Match/Leaks
A correctly fitted masks is essential for efficient and quiet CPAP remedy. Masks leaks, arising from an improper match or seal, are a significant contributor to perceived machine loudness. These leaks not solely disrupt the meant strain supply but in addition generate further noise, typically described as hissing, whistling, or whooshing. Addressing masks match points immediately impacts remedy success and minimizes noise disturbances.
-
Leak Supply Identification
Pinpointing the leak supply is step one towards decision. Leaks can originate from varied places: across the nostril bridge, cheeks, or mouth. Observing the course of escaping air and noting any discomfort or strain factors on the face helps establish the precise space requiring adjustment. For example, a leak close to the nostril bridge may point out the necessity for a special masks measurement or cushion kind. A leak close to the mouth might counsel jaw dropping throughout sleep, necessitating a chin strap or full-face masks.
-
Masks Adjustment and Positioning
Adjusting headgear straps and repositioning the masks on the face can typically resolve minor leaks. Straps needs to be cosy however not overly tight, guaranteeing a safe seal with out inflicting discomfort or strain sores. Slight changes to the masks angle or place on the face can typically dramatically enhance the seal. For instance, a barely downward tilt of the masks may resolve a leak on the nostril bridge. Experimenting with completely different strap changes and masks positions is vital to discovering the optimum match.
-
Masks Sort and Measurement Concerns
Deciding on the suitable masks kind and measurement is key for a correct match. Totally different facial constructions and sleep positions necessitate completely different masks designs. Nasal pillow masks, superb for some, is likely to be unsuitable for others susceptible to mouth respiration. Full-face masks, whereas efficient for mouth breathers, may really feel cumbersome for others. Correct sizing is equally essential. A masks that’s too massive or too small will inevitably result in leaks. Consulting with a sleep specialist for knowledgeable becoming ensures the collection of a masks tailor-made to particular person wants and anatomy.
-
Masks Upkeep and Alternative
Common masks upkeep is crucial for stopping leaks and sustaining a correct seal. Cushions, the a part of the masks that immediately contacts the face, deteriorate over time, shedding their pliability and sealing capability. Common cleansing and substitute in accordance with producer suggestions guarantee optimum efficiency and reduce the chance of leaks. Moreover, inspecting the masks and headgear for put on and tear, similar to cracks or fraying straps, is essential for figuring out potential leak sources and guaranteeing continued effectiveness.
Addressing masks match and leaks is paramount for minimizing CPAP machine noise and guaranteeing efficient remedy. By understanding the potential sources of leaks, using correct becoming strategies, and sustaining masks elements, customers can considerably cut back noise disturbances and enhance general sleep high quality. A quiet and cozy CPAP expertise immediately contributes to remedy adherence and the long-term well being advantages related to treating sleep apnea.
5. Humidification
Humidification, a typical function in trendy CPAP machines, introduces moisture to the pressurized airflow, assuaging widespread uncomfortable side effects like dry nasal passages and throat irritation. Whereas humidification contributes to general remedy consolation, it could possibly affect perceived machine noise in a number of methods. The act of heating water and producing humidity provides a refined effervescent or gurgling sound to the present machine noise. This extra sound, whereas typically quiet, could be noticeable in in any other case quiet environments. Moreover, elevated humidity can typically amplify the sound of airflow turbulence inside the masks and tubing, doubtlessly making the general expertise appear louder. For instance, a person may understand their machine as louder with humidification energetic in comparison with utilizing it with out humidification, even when the core machine noise stays fixed. The change in air density because of added moisture can alter sound transmission traits.
The extent of humidification additionally influences perceived noise. Greater humidity settings, delivering extra moisture, typically end in extra pronounced effervescent sounds from the humidifier chamber. Conversely, decrease settings or utilizing the humidifier with out heating the water minimizes the added sound. The kind of humidifier additionally performs a task. Built-in, heated humidifiers, constructed immediately into the CPAP machine, typically function extra quietly than exterior, standalone humidifiers. Moreover, some humidifiers make the most of superior applied sciences, similar to adaptive humidity management, which robotically adjusts moisture output based mostly on ambient situations and respiration patterns. These adaptive options can reduce fluctuations in humidity ranges, thus lowering variations within the related sounds. Common upkeep of the humidifier chamber, together with cleansing and correct water ranges, prevents mineral buildup and ensures optimum, quiet operation. Ignoring upkeep can result in elevated noise from the humidifier, doubtlessly masking different refined sounds and hindering correct troubleshooting of different CPAP noise sources.
Understanding the nuances of how humidification impacts CPAP sound permits for knowledgeable changes and troubleshooting. Whereas the added sound of humidification is mostly minimal in comparison with the core machine noise and potential masks leaks, it may be an element for noise-sensitive people. Deciding on a CPAP machine with a quiet, built-in humidifier and using acceptable humidity settings tailor-made to particular person wants can stability consolation and reduce noise impression. Common upkeep and correct utilization practices additional guarantee quiet and efficient humidification, contributing to a extra optimistic and cozy CPAP remedy expertise.
6. Tubing
The tubing connecting the CPAP machine to the masks performs a refined but important function within the general sound profile of CPAP remedy. Whereas typically ignored, the kind, size, and situation of the tubing can affect noise ranges and impression person expertise. Understanding these components permits for optimization and minimization of noise associated to the tubing.
-
Tubing Diameter
Commonplace CPAP tubing sometimes has a diameter of 22mm. Nonetheless, some machines make the most of slimline or “micro” tubing with a smaller diameter. This narrower tubing, whereas lighter and extra moveable, can improve airflow velocity, doubtlessly resulting in higher-pitched sounds because of elevated air resistance. The broader diameter tubing permits for slower airflow, typically producing much less noise.
-
Tubing Size
Longer tubing can contribute to elevated noise because of the better floor space for sound to resonate. Whereas customary tubing lengths are typically ample, excessively lengthy tubing can amplify airflow sounds. Protecting the tubing as quick as virtually doable with out limiting motion throughout sleep can reduce this impact. For example, arranging the CPAP machine nearer to the mattress reduces the necessity for extreme tubing size and minimizes potential noise.
-
Tubing Materials and Building
Most CPAP tubing is constructed from smooth-bore, light-weight plastic. This materials minimizes friction and air resistance, contributing to quieter operation. Nonetheless, some tubing incorporates options like heated insulation to stop condensation buildup. Whereas useful for consolation, this added insulation can typically alter sound transmission traits. Moreover, the pliability of the tubing materials influences noise. Stiffer tubing can transmit vibrations extra readily, doubtlessly growing perceived noise in comparison with extra versatile tubing.
-
Tubing Upkeep
Over time, CPAP tubing can accumulate mud, particles, and condensation, doubtlessly affecting airflow and growing noise. Common cleansing and substitute of the tubing, as really helpful by the producer, is essential for sustaining optimum efficiency and minimizing noise. A buildup of particles inside the tubing can limit airflow, resulting in elevated turbulence and noise. Likewise, neglecting to dry the tubing after cleansing can introduce moisture, additional affecting airflow and sound. Correct upkeep ensures constant airflow and minimizes noise associated to blockages or moisture buildup.
Whereas tubing won’t be the first supply of noise in CPAP remedy, its contribution shouldn’t be disregarded. Addressing components like diameter, size, materials, and upkeep can optimize airflow, reduce noise, and enhance general remedy consolation. Cautious consideration to those particulars, mixed with different noise discount methods, contributes to a extra optimistic and efficient CPAP expertise.
7. Filters
CPAP machines make the most of filters to take away airborne particles, guaranteeing the supply of fresh air to the person. These filters, whereas important for hygiene and machine longevity, can contribute to the general sound profile of the machine. Understanding the connection between filters and noise ranges is essential for optimizing the CPAP expertise.
-
Filter Sorts and Noise Ranges
CPAP machines sometimes make use of two varieties of filters: disposable effective filters and reusable foam filters. Positive filters, designed to entice smaller particles like mud and pollen, can limit airflow greater than foam filters, doubtlessly resulting in a slight improve in noise because of increased air velocity. Foam filters, whereas capturing bigger particles, supply much less airflow resistance, typically contributing much less to general noise. Some machines make the most of each filter varieties concurrently, providing complete filtration whereas aiming to attenuate noise impression. The selection of filter and its situation can affect the refined nuances of sound produced by the machine.
-
Filter Situation and Airflow
As filters accumulate particles, airflow resistance will increase. This restricted airflow can result in an increase in noise ranges because of the increased strain required to take care of the prescribed remedy strain. A clogged filter forces the machine to work more durable, producing extra noise. Recurrently changing disposable filters and cleansing reusable filters, as really helpful by the producer, is crucial for sustaining optimum airflow and minimizing noise related to elevated air resistance. Neglecting filter upkeep not solely will increase noise but in addition compromises the effectiveness of the remedy and the longevity of the machine. For instance, a closely dirty filter may produce a noticeable whirring sound because the machine strains to take care of strain, whereas a clear filter permits for quieter operation.
-
Filter Housing and Design
The design and development of the filter housing inside the CPAP machine may also affect noise ranges. Some housings are designed to attenuate airflow turbulence and dampen sound, whereas others may inadvertently amplify sure frequencies. The position of the filter inside the machine and the supplies used within the housing can impression how sound travels by the machine. Whereas these design parts are sometimes past the person’s management, understanding their potential impression on noise could be useful when troubleshooting or choosing a brand new machine. For example, a poorly designed filter housing may create a whistling sound because of air turbulence across the filter, even when the filter itself is clear.
-
Interplay with Different Noise Sources
Filter-related noise typically interacts with different noise sources inside the CPAP system. A barely louder airflow because of {a partially} clogged filter may exacerbate the noise from a leaky masks, making a cumulatively louder expertise. Addressing all potential noise sources holistically is crucial for reaching optimum quietness. Ignoring a unclean filter whereas focusing solely on masks match won’t totally resolve the noise challenge. A complete strategy to noise discount considers the interaction of all elements, together with filters, masks, tubing, and the machine itself.
Whereas filters play an important function in sustaining clear airflow, their impression on CPAP machine noise shouldn’t be ignored. Correct filter choice, common upkeep, and an understanding of how filter situation and housing design affect sound are essential for minimizing noise and maximizing remedy consolation. Addressing filter-related noise, along with different noise discount methods, ensures a quieter and more practical CPAP remedy expertise, selling higher sleep high quality and long-term adherence to remedy.
8. Machine Placement
Machine placement considerably influences perceived CPAP noise ranges. Positioning the machine on a tough, resonant floor, similar to a nightstand or dresser, can amplify motor vibrations and operational sounds. These surfaces act as soundboards, reflecting and intensifying the noise. Conversely, putting the machine on a softer, absorbent floor, like a carpeted ground or a padded mat, can dampen vibrations and cut back general noise output. The distinction in perceived loudness between these two placement eventualities could be substantial, affecting each the person and anybody sharing the sleeping house. For instance, putting the machine immediately on a wood nightstand may make the motor noise extra pronounced, whereas putting it on a thick rug on the ground can considerably cut back the perceived sound.
Past the floor materials, the placement of the machine relative to the mattress and different furnishings additionally impacts noise ranges. Putting the machine nearer to the top of the mattress, whereas handy for tubing administration, can improve the perceived loudness because of proximity. Positioning the machine additional away, similar to on a chair or shelf, reduces direct sound transmission. Nonetheless, this necessitates longer tubing, which might introduce different noise concerns. Obstacles between the machine and the mattress, similar to furnishings or curtains, may help take up and diffuse sound waves, additional lowering perceived noise. Strategic placement, contemplating each floor materials and placement, minimizes noise propagation and contributes to a quieter sleep surroundings. For instance, putting the machine behind a nightstand, somewhat than immediately on prime of it, can create a sound barrier and cut back direct noise transmission in the direction of the sleeper.
Optimizing machine placement is a straightforward but efficient technique for minimizing CPAP noise. Cautious consideration of floor materials, proximity to the mattress, and the presence of sound-absorbing obstacles permits customers to create a extra conducive sleep surroundings. Addressing machine placement, along with different noise discount strategies, improves remedy consolation and promotes long-term adherence. This proactive strategy acknowledges that even small changes in machine placement can considerably impression perceived noise ranges and contribute to a extra optimistic CPAP expertise.
9. Ambient Noise
Ambient noise, the background sound current in any surroundings, performs a major function within the notion of CPAP machine noise. The interaction between ambient noise ranges and CPAP sounds influences how intrusive the machine’s operation is perceived. In quieter environments, even refined CPAP sounds can develop into extra noticeable, whereas in environments with increased ambient noise, the identical CPAP sounds could also be masked or much less disruptive. This masking impact could be likened to the best way a ticking clock is well heard in a silent room however turns into imperceptible in a loud surroundings. Understanding this relationship is essential for managing and mitigating perceived CPAP noise. For instance, in a quiet bed room, the hum of the CPAP motor is likely to be distinguished, whereas in a room with a operating fan or white noise machine, the motor sound turns into much less noticeable.
Strategic use of ambient noise could be a precious device in lowering CPAP noise disruption. Introducing white noise, nature sounds, or perhaps a fan can successfully masks the sounds of the CPAP machine, making them much less intrusive and selling higher sleep. The selection of ambient noise will depend on particular person preferences; some discover the constant sound of white noise soothing, whereas others favor the extra various sounds of nature. The amount of the ambient noise can also be essential; it needs to be loud sufficient to masks the CPAP sounds however not so loud as to disrupt sleep in itself. Experimentation with differing types and volumes of ambient noise may help people discover the simplest technique for his or her particular wants. Moreover, addressing underlying causes of CPAP noise, similar to masks leaks or improper machine placement, along with introducing ambient noise, supplies a complete strategy to noise discount. Relying solely on ambient noise to masks a loud machine won’t be as efficient as addressing the basis reason behind the noise first. For example, utilizing earplugs together with a white noise machine can additional cut back the notion of CPAP noise, making a extra peaceable sleep surroundings.
Managing ambient noise supplies a sensible and readily accessible methodology for mitigating perceived CPAP machine noise. Strategic introduction of background sounds can considerably enhance remedy consolation and promote adherence by lowering noise-related disruptions. This strategy, mixed with addressing potential mechanical noise sources inside the CPAP system itself, gives a holistic technique for minimizing noise and maximizing the therapeutic advantages of CPAP remedy. It is vital to think about particular person sensitivities to sound and alter ambient noise methods accordingly, guaranteeing the chosen methodology promotes rest and restful sleep somewhat than creating further disturbances.
Often Requested Questions About CPAP Noise
Addressing considerations about CPAP machine noise is crucial for profitable remedy. This part supplies solutions to widespread questions, providing sensible insights and options for minimizing noise disruption.
Query 1: How loud is a typical CPAP machine?
Trendy CPAP machines typically function at round 30 decibels, akin to a whisper. Nonetheless, perceived loudness can fluctuate based mostly on components like machine kind, strain settings, and masks leaks.
Query 2: Are some CPAP machines quieter than others?
Sure, producers prioritize noise discount in newer fashions. Machines with brushless motors and sound-dampening options are inclined to function extra quietly. Consulting with a sleep specialist may help establish quieter choices.
Query 3: Can masks leaks make a CPAP machine sound louder?
Completely. Masks leaks create hissing or whistling sounds, considerably growing perceived noise ranges. Making certain a correct masks match is essential for minimizing noise and maximizing remedy effectiveness.
Query 4: Does utilizing a humidifier make the CPAP machine louder?
Humidification can add a refined effervescent sound. Nonetheless, the advantages of added moisture typically outweigh the minimal improve in noise. Correct humidifier upkeep additionally minimizes noise.
Query 5: What could be performed to scale back CPAP machine noise?
A number of methods can reduce noise, together with utilizing a quieter machine, guaranteeing a correct masks match, utilizing earplugs, optimizing machine placement, and introducing ambient noise like white noise or a fan.
Query 6: If the CPAP machine appears excessively loud, what ought to one do?
Contact the gear supplier or a sleep specialist. They will assess the machine, masks, and settings to establish the noise supply and advocate acceptable options.
Addressing noise considerations proactively contributes to a extra optimistic CPAP expertise. Efficient noise administration promotes remedy adherence and the long-term well being advantages related to treating sleep apnea.
The following part will delve deeper into choosing the correct CPAP gear for particular person wants, additional enhancing remedy consolation and effectiveness.
Suggestions for Minimizing CPAP Noise
Minimizing CPAP machine noise is essential for remedy consolation and adherence. The next ideas supply sensible methods for lowering noise and selling restful sleep.
Tip 1: Prioritize Machine Choice: Choosing a more moderen CPAP machine designed with noise discount options, similar to brushless motors and sound-dampening supplies, considerably reduces operational noise. Consulting with a sleep specialist or sturdy medical gear supplier ensures entry to the quietest choices out there.
Tip 2: Optimize Masks Match: A correctly fitted masks is paramount for minimizing leaks, a significant supply of noise. Recurrently checking for leaks and looking for skilled help with masks becoming ensures a safe seal and reduces disruptive hissing or whistling sounds.
Tip 3: Strategic Machine Placement: Positioning the CPAP machine on a mushy, absorbent floor, similar to a carpeted ground or a padded mat, dampens vibrations and reduces noise. Avoiding laborious, resonant surfaces minimizes sound amplification.
Tip 4: Make the most of Ambient Noise: Introducing white noise, nature sounds, or a fan can successfully masks CPAP machine sounds, making them much less noticeable and selling rest. Experimenting with completely different sound varieties and volumes identifies optimum masking ranges.
Tip 5: Preserve Tools: Recurrently cleansing and changing filters, tubing, and masks cushions as really helpful by the producer ensures optimum airflow and minimizes noise related to blockages or leaks. Correct upkeep contributes to each quieter operation and general remedy effectiveness.
Tip 6: Think about Tubing Choices: Deciding on shorter tubing lengths and wider diameter tubing can reduce airflow noise. Keep away from excessively lengthy tubing and discover choices like heated tubing to attenuate condensation and related gurgling sounds.
Tip 7: Modify Humidification Settings: Whereas humidification provides consolation, increased settings can improve noise. Experimenting with decrease humidity ranges or utilizing unheated humidification may cut back noise with out sacrificing consolation. Common cleansing of the humidifier chamber prevents mineral buildup and related noise.
Implementing these methods creates a quieter and extra comfy CPAP expertise, selling higher sleep high quality and elevated remedy adherence. Constant consideration to those particulars contributes to the long-term well being advantages related to efficient sleep apnea remedy.
The next conclusion summarizes the important thing takeaways for minimizing CPAP machine noise and emphasizes the significance of looking for skilled steerage for customized options.
Conclusion
CPAP machine noise ranges, a frequent concern amongst customers, can considerably impression remedy success. This exploration has highlighted varied components influencing perceived loudness, together with machine kind, masks design and match, airflow strain, humidification settings, tubing traits, filter upkeep, machine placement, and the affect of ambient noise. Addressing these components by knowledgeable gear decisions, correct upkeep practices, and strategic environmental changes can successfully reduce noise disruption.
Efficient administration of CPAP noise is essential for long-term remedy adherence and the belief of related well being advantages. Looking for steerage from sleep specialists and respiratory therapists supplies customized options tailor-made to particular person wants. Continued developments in CPAP expertise promise even quieter and extra comfy remedy experiences, additional bettering the lives of these affected by sleep apnea.
