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foram avaliados quatro pacientes jovens com dmd que anteriormente recusaram - se a se submeter  vni .
os quatro pacientes toleraram bem a vb e aderiram ao uso de vni em casa . o uso de vb provou ser uma alternativa prefervel e mais confortvel que o uso de vni com qualquer outro tipo de interface .
dois dos pacientes necessitaram de vni noturna e eventualmente aceitaram utilizar uma mscara nasal durante a noite .
as vantagens da vb sobre outros tipos de vni incluem menores problemas na fala , melhor aparncia e menor impacto no paciente , eliminando o risco de leses na pele , distenso gstrica , conjuntivite e claustrofobia .
o uso da interface bucal sempre deve ser considerado em pacientes com dmd que necessitam iniciar vni a fim de promover uma abordagem positiva e uma rpida aceitao da vni . o uso diurno de vb faz com que os
alm disso , a vb aumenta a adeso ao tratamento naqueles pacientes que se recusam a utilizar outros tipos de interfaces .
duchenne muscular dystrophy ( dmd ) is one of the most common neuromuscular diseases in childhood .
the young patient often needs noninvasive mechanical ventilation ( niv ) due to the development of respiratory failure , reduction in fvc , or nocturnal hypoventilation symptoms . 


 
patients with neuromuscular disease might also function extremely well with minimal symptoms despite significant reductions in fvc and severe nocturnal oxygen desaturation . 
 
for this reason and for the poor tolerance of the interface , sometimes the young patient does not accept niv easily .
poor tolerance of the interface can be caused by various factors , such as excessive pressure of the mask on the face , excessive oral air leakage , anxiety of the patient because he or she is unable to call a family member , claustrophobia , and patient - ventilator dyssynchrony . 
 
thus , the interface plays a crucial role in tolerance and effectiveness of niv use .
interfaces that cover the nose or the nose and mouth ( oronasal interface ) are the most commonly used ; however , they are more likely to cause skin breakdown , gastric distension , conjunctivitis , and claustrophobia . 
 
although there are various types of interfaces nowadays , the physiognomy of the patient often makes the choice of a suitable interface difficult .
the most common drawbacks can be avoided by using mouthpiece niv ( mpv ) interfaces , and , in recent years , mpv modes have been introduced to some of the portable ventilators available .
patients were studied in our respiratory department between january of 2015 and april of 2015 .
we evaluated four young patients with dmd , with a mean of 18.5 years of age ( table 1 ) .
three patients ( labeled as patients 1 , 2 , and 3 ) showed reductions in fvc ( < 50% than the previous control measurement ) and progressive decreases in pao2 .
the four patients presented with an fvc  1 l , and patients 1 and 4 presented with hypercapnia and nocturnal respiratory failure .
patient 1 presented with obstructive sleep - disordered breathing ( sdb ) , and sleep monitoring demonstrated an apnea - hypopnea index = 20 events / h .
patient 4 presented with sleep hypoventilation syndrome ; sleep monitoring demonstrated an increase in paco2 > 10 mmhg at waking in the morning ( when compared with awake supine values ) and sustained hypoxemia not related to apnea or hypopnea ( sao2 < 90% over 30% of the monitoring period during sleep ; t90 > 30% ) , demonstrating sdb . 

table 1characteristics of the patients and noninvasive ventilation settings.patientage , yearsfvc , lpao2 
 paco2 
 sdbcause of niv refusalmodeipap , cmh2oepap , cmh2oit , srt , srr , cycles / min1211,078947yesfear and anxietympv / pc1201,2302160,916945noclaustrophobiampv / pc1401,2303180,967044noskin intolerancempv / pc1401,2304191,028151yesfear and anxietympv / pc1501,440sdb : sleep - disordered breathing ; niv : noninvasive ventilation ; ipap : inspiratory positive airway pressure ; epap : expiratory positive airway pressure ; it : inspiratory time ; rt : rise time ; rr : respiratory rate ; and mpv / pc : mouthpiece ventilation / pressure control . 
 
sdb : sleep - disordered breathing ; niv : noninvasive ventilation ; ipap : inspiratory positive airway pressure ; epap : expiratory positive airway pressure ; it : inspiratory time ; rt : rise time ; rr : respiratory rate ; and mpv / pc :
the patients had previously refused to use niv due to claustrophobia , fear of being unable to communicate with family members while using it , and annoying leaks . each patient was reassessed and proposed to try using mpv .
the subjects were submitted to niv using a mechanical ventilator ( trilogy ; philips respironics , murrysville , pa , usa ) that has a dedicated particular function designated " kiss trigger " mpv and an arm dedicated to support the mouthpiece in order to facilitate its use and allow the patient to stay on a wheelchair ( figure 1 ) . during the adaptation phase
, we presented the mouthpiece interface to the patients and selected the most comfortable position of the support arm according to the postural impairment of the patient .
the preferred mode in the initial phase was pressure control , with a support of 8 - 10 cmh2o , which was gradually increased until a suitable tidal volume , an optimal spo2 ( confirmed by blood gas analysis ) , a stable hr , and good chest expansion ( measured by electrical impedance tomography - pulmovista 500 ; drger medical gmbh , lbeck , germany ) were reached .
inspiratory time was set at 1.2 s ( for patients 1 , 2 , and 3 ) , and 1.4 s ( for patient 4 ) .
for all patients , the expiratory positive airway pressure ( epap ) was set to 0 cmh2o ; the rise time amounted to 3 s ( for patients 1 , 2 , and 3 ) and 4 s ( for patient 4 ) .
all patients tolerated this new ventilation mode well , with good compliance to the interface .
all patients accepted the treatment , and they continued niv at home . at this writing , none of the dmd patients had been unable to retain the mouthpiece as a result of weakness . 

the results for patients 2 and 3 showed dilated bowel loops and upward displacement of the diaphragm ( figure 2 ) . 

figure 2a chest x - ray showing dilated bowel loops and upward displacement of the diaphragm . 
 
after an initial phase of adaptation to mpv during daytime hours , thanks to a greater feeling of security , patients 1 and 4 also accepted niv with a nasal mask during the night .
patient 1 was adapted to spontaneous - timed average volume assured pressure support ( st - avaps ) ventilation mode ; maximum inspiratory positive airway pressure ( ipap ) = 14 and 10 cmh2o ; minimum ipap = 10 cmh2o ; epap = 6 cmh2o ; avaps rate = 1 cmh2o / min ; tidal volume = 650 ml ; trigger flow = 4.0 l ; cycle = 25% ; rise time = 3 s ; rr = 10 breaths / min ; and inspiratory time = 1.2 s in a simple circuit configuration .
patient 4 was adapted to assist - control ventilation ( acv ) mode ; vc = 750 ml ; rr = 12 breaths / min ; inspiratory time = 1.2 s ; decelerated flow ; and epap = 4 cmh2o ( table 2 ) . 

table 2mouthpiece ventilation settings for patients 1 and 2.patientmodeipapmin , cmh2oipapmax , cmh2oepap , cmh2oavaps ratevt , ltgcyclert , srr , breaths / minit , sinterface1st - avaps101461650425%3101,2nasal4ac 

 4 
 750 



 1,2nasalipapmin : minimum inspiratory positive airway pressure ; ipapmax : maximum inspiratory positive airway pressure ; epap : expiratory positive airway pressure ; avaps : average volume assured pressure support ; vt : tidal volume ; tg : trigger flow ; rt : rise time ; rr : respiratory rate ; it : inspiratory time ; st : spontaneous - timed ; and ac : assist - control 
  ipapmin : minimum inspiratory positive airway pressure ; ipapmax : maximum inspiratory positive airway pressure ; epap : expiratory positive airway pressure ; avaps : average volume assured pressure support ; vt : tidal volume ; tg : trigger flow ; rt : rise time ; rr : respiratory rate ; it : inspiratory time ; st : spontaneous - timed ; and ac : assist - control oxyhemoglobin saturation was measured using pulse oximetry ( palmsat 2500a ; nonin medical , plymouth , mn , usa ) , and paco2 was measured using a transcutaneous blood gas monitor ( linde microgas 7650 ; linde medical sensors ag , basel , switzerland ) or arterial blood gases when the transcutaneous monitor was unavailable while the patient was awake .
adequate ventilatory support was assessed using a combination of clinical assessment , normal overnight oximetry , serial daytime measures of paco2 , and downloaded data from the devices .
all of the patients had previously refused to use niv , but accepted treatment with mpv .
ipap was set between 10 and 14 cmh2o , which ensured an optimal tidal volume ( 8 - 10 ml / kg ) .
no back - up rate was needed during daytime , so no air blew into the face of the patients . in this configuration , the equipment could be set without epap .
alarms for apnea , minimum pressure , and minimum volume could be easily shut off in order to avoid their unnecessary activation . in most home volume - controlled ventilators ,
the minimum pressure alarm can not be deactivated ; therefore , it is necessary to set up positive end - expiratory pressure ( often at 2 cmh2o ) , which , thanks to the resistance to the airflow created from the angle of the mouthpiece , creates a pressure that prevents the continuous activation of the alarms .
patient 1 presented with sleep apnea syndrome . during night time , he was treated using st - avaps mode , which allowed greater comfort and better fit .
a trigger with an average sensitivity was better tolerated than a more sensitive trigger , which was initially set .
patient 2 presented with sleep hypoventilation syndrome and adapted to the acv mode well , reducing respiratory effort and improving nocturnal breathing pattern .
respiratory disease is a nearly inevitable complication in patients with dmd and represents the underlying cause of death in 70% of the patients with less than 25 years of age . 
 
it has been widely demonstrated that mechanical ventilation corrects respiratory failure and can prolong the life of those patients . 
 
it is known that niv improves gas exchange , relieves shortness of breath , allows inspiratory muscles to rest , and reduces the incidence of nosocomial infections .
in addition , mortality and hospitalizations due to respiratory failure decrease . 
  in our experience ,
nasal and oronasal masks are the most practical ( and most commonly used ) for niv
. 
  the main limitations to the use of these interfaces are claustrophobia , discomfort , and skin lesions . 


 
the application of an oronasal interface can worsen social interaction , since it impairs eating , drinking , and talking .
this type of mask changes the patient 's perception of himself and may have negative psychological consequences . 
 
the preferable and more comfortable alternative is mpv via a 15- or 22-mm mouthpiece device ; however , more active participation of the patient is necessary than with the use of traditional masks .
we preferred the ' ' kiss trigger '' mpv function of the ventilator , because the patient has only to touch it for air delivery .
there is a system in which the mouthpiece should be placed close to the mouth by the adjustable arm , and the patient can grab the mouthpiece as desired .
the most significant advantages of mpv when compared with the use of a nasal or an oronasal mask are that the mouthpiece interferes with speech to a lesser degree , improves appearance , reduces the negative impact on the patient , and eliminates the risk of skin breakdown and claustrophobia . 
 
additionally , it is safer than the other interfaces since it permits the use of glossopharyngeal breathing in the event of a sudden ventilator failure or an accidental disconnection from the ventilator .
a recent comparative study on the performance of different home ventilators showed that mpv and the use of a whisper valve were associated with a reduction in the number of alarms when compared with the other configurations available in the trilogy ( philips respironics ) ventilator .
the authors emphasized that the " kiss trigger " function in that ventilator is not comparable with functions in classical ventilators , since it is based on a flow signal technology that detects an alteration in the flow - by mode generated by the ventilator due to any reason , such as a partial obstruction via the mouth connection . 

 
all of the patients in the present study had previously rejected the application of niv due to the tightness of the interface and claustrophobia , resulting in poor compliance .
the patients who required overnight niv subsequently accepted the treatment via a nasal mask during the night hours .
this was probably due to the fact that the use of mpv during daytime hours made the patients feel safe , gradually being confident enough for using niv at night .
the use of the nasal mask and mpv with that specific ventilator ( trilogy ; philips respironics ) allowed us to treat the patients who had previously refused nasal , oral , or oronasal interfaces .
the use of a mouthpiece interface should be always considered for patients with dmd who need to start niv ; it is useful to promote a positive approach and a rapid acceptance of the new condition .
as time goes by , patients with dmd develop constant hypoventilation and need respiratory support 24 h a day ; mpv can be valuable , particularly in patients who undergo niv various hours a day and who present with skin lesions , gastric distension , or eye irritation .
abstractobjective : to evaluate mouthpiece ventilation ( mpv ) in patients with duchenne muscular dystrophy ( dmd ) who are noncompliant with noninvasive ventilation ( niv ) . 
 methods : we evaluated four young patients with dmd who had previously refused to undergo niv . 
 each patient was reassessed and encouraged to try mpv . 
 results : the four patients tolerated mpv well and were compliant with niv at home . mpv proved to be preferable and more comfortable than niv with any other type of interface . 
 two of the patients required overnight niv and eventually agreed to use a nasal mask during the night . 
 conclusions : the advantages of mpv over other types of niv include fewer speech problems , better appearance , and less impact on the patient , eliminating the risk of skin breakdown , gastric distension , conjunctivitis , and claustrophobia . the use of a mouthpiece interface should be always considered in patients with dmd who need to start niv , in order to promote a positive approach and a rapid acceptance of niv . using mpv during the daytime 
 makes patients feel safe and more likely to use niv at night . 
 in addition , mpv increases treatment compliance for those who refuse to use other types of interfaces .