Comparison of nose and face mask CPAP therapy for sleep apnoea

BACKGROUND—Many patients with sleepapnoea/hypopnoea syndrome (SAHS) find nasal continuous positive airwaypressure (CPAP) treatment unsatisfactory due to side effects related tomouth air leakage. A study was performed to compare side effects withface mask and nose mask CPAP therapy in patients with SAHS, with andwithout uvulopalatopharyngoplasty (U3P).
METHODS—Twenty newly diagnosed patients with SAHStook part in a randomised double limb trial of face or nose mask CPAPtherapy (four weeks per limb) in which CPAP compliance in terms ofmachine run time was measured and patients answered a symptomquestionnaire on side effects resulting from the mask. Ten patientswith SAHS with U3P (SAHS/U3P) who were already regular users of nasalCPAP were also given a four week trial of face mask CPAP to compare compliance and symptoms. Ten patients with SAHS were matched with the10 SAHS/U3P patients for body mass index, age, apnoea/hypopnoea index,and CPAP pressure. Long term compliance was estimated one year afterthe mask comparison studies.
RESULTS—For patients with SAHS nightly compliancewas higher with a nose mask (mean (SE) 5.3 (0.4) hours/night CPAP) thanwith a face mask (4.3 (0.5) hours/night CPAP), p = 0.01 (meandifference 1.0hour/night, 95% CI 1.8 to 0.3). Nose masks were ratedmore comfortable by 19 of 20 patients (p<0.001) despite more mouthleak related symptoms. For SAHS/U3P patients compliance was marginallyhigher with nose masks (5.1 (0.7) hours/night CPAP) than with facemasks (4.0 (0.8) hours/night CPAP), p = 0.07 (mean difference 1.1 hour/night, 95% CI 2.1 to 0.1). Nose masks were rated more comfortableby seven of 10 patients. There were no significant differences in sideeffect scores with face and nose masks. At one year nine of 10 SAHSpatients and nine of 10 SAHS/U3P patients were still using CPAP.Compliance was 5.4 (0.6) hours/night for the SAHS patients and 3.5 (0.4) hours/night for the SAHS/U3P patients, p = 0.02 (mean difference1.9 hour/night, 95% CI 3.6 to 0.3).
CONCLUSIONS—Compliance is greater with nose maskCPAP than with face mask CPAP because the overall comfort is better andcompensates for increased symptoms associated with mouth leakage.Improved face mask design is needed.

     

Nasal CPAP therapy: effects of different CPAP levels on pressure transmission into the trachea and pulmonary oxygen transfer

Background: Nasal continuous positive airway pressure (nCPAP) is considered useful for prophylaxis and treatment of respiratory complications following major thoracic surgery. It is unknown, however, which CPAP levels are required to avoid alveolar derecruitment and to consistently improve pulmonary oxygen transfer in patients following thoracotomy. We therefore studied the effects of different nCPAP levels on pressure transmission into the trachea as well as on pulmonary oxygen transfer. Methods: In 10 consecutive patients after cardiac or thoracic vascular surgery, following extubation in the ICU, nCPAP was generated by means of a high‐flow gas source and applied randomly at levels of 5 or 10 cm H₂O. Airway pressure was recorded continuously in the nasal mask and the trachea. The PaO₂/FiO₂ratio was calculated from the tracheal oxygen concentration, and PaO₂ was determined while breathing at an ambient and elevated airway pressure. Haemodynamic variables (heart rate, arterial blood pressure, central venous pressure) were also recorded. Results: Mean pressures in the nasal mask were 5.4±0.1 and 9.7±0.3 cm H₂O. Corresponding tracheal pressures were 2.8±1.0 vs. 7.2±1.1 cm H₂O (P=0.007). With higher mask pressure, the fraction of pressure transferred from the nasal mask into the trachea was larger (0.75±0.03 vs. 0.52±0.05; P=0.04), and tracheal pressures remained positive during the entire respiratory cycle in all patients. In contrast, with 5.4 cm H₂0, negative pressure changes during inspiration occurred in five out of 10 patients. The PaO₂/FiO₂ ratio increased from 183±53 (ambient pressure) to 199±74 (nCPAP 5.4 cm H₂O; P=0.25) and to 333±54 (nCPAP 9.7 cm H₂O; P=0.003). Nasal CPAP did not alter hemodynamics. Conclusion: Nasal CPAP is an effective non‐invasive means of increasing tracheal and thus intrathoracic pressure without adverse hemodynamic effects. Only mask pressures of 9–10 cm H₂O were sufficient to consistently improve pulmonary oxygen transfer in patients following thoracotomy.     

Application of nasal flexible laryngeal mask airway in anesthesia for oral surgery

The laryngeal mask airway has been used increasingly in clinics but is seldom applied in anesthesia for oral surgery, as the mask occupies the middle of the mouth and tends to obstruct the surgical field. Here, we report the successful placement and usage of a nasal flexible laryngeal mask airway (FLMA) in an oral surgical procedure. Fifteen patients undergoing dental procedures under general anesthesia were studied. We clinically applied a previously reported method for inserting an FLMA with some modifications. There was no significant bleeding from the intubated nostril in any of the patients. None of the patients complained of sore throat, coughing, hoarseness, or any discomfort in the nose. Although we anticipate that further refinements of the technique may be possible and that the safety of this method using a nasal FLMA needs to be assessed in a greater number of patients, in this preliminary study we provide a proof-of-principle demonstration of the efficacy of nasal LMA ventilation as a method of airway management for oral surgery.     

Nasopharyngeal airway continuous positive airway pressure: a method to wean from or avoid mechanical ventilation in adults

A simple technique using a nasopharyngeal airway and a continuous positive airway pressure circuit has proved an effective alternative to a tight fitting nasal or face mask for delivery of continuous positive airway pressure. Nasal trauma, discomfort and mouth breathing are the main disadvantages.     

Nasal CPAP after coronary artery surgery

Two groups of 14 patients were compared after coronary artery bypass surgery where the left internal mammary artery had been used as a conduit. One group received nasal continuous positive airway pressure for 1 h, the other group acted as a control. Mean pulmonary shunt fraction was 16.3% before, 12.6% during and 15.7% after continuous positive airways pressure. In the control group the shunt fraction fell from 17.3% to 16.8%. The reduction in shunt fraction was significantly greater with nasal continuous positive airways pressure than in the control group (p = 0.016). There was a significant reduction (p = 0.025) in respiratory rate from 18.3 to 16.7 breath.min-1 during continuous positive airway pressure. Other measured cardiorespiratory variables did not differ significantly between the groups. Visual analogue scores showed no significant difference in chest pain or mask comfort between the groups. The ease of breathing score was, however, significantly better in the continuous positive airways pressure group, 7.5 (SD 1.8) cm and control 5.6 (SD 2.6) cm.     

Compliance with CPAP therapy in patients with the sleep apnoea/hypopnoea syndrome.

BACKGROUND--Continuous positive airway pressure (CPAP) therapy is the treatment of choice for the sleep apnoea/hypopnoea syndrome. Compliance with this relatively obtrusive therapy has not been well studied. METHODS--Usage of CPAP was investigated in 54 patients with sleep apnoea/hypopnoea syndrome (median 36 (range 7-129) apnoeas + hypopnoeas/hour slept) over the first 1-3 months after starting CPAP therapy. In all cases CPAP usage was monitored by hidden time clocks that indicated for how long the machines were switched on--that is, the CPAP run time. In 32 patients the time at which the CPAP mask pressure was at the therapeutic level of CPAP pressure set for that patient--that is, the mask time--was also monitored. In all patients objective daytime sleepiness was assessed by multiple sleep latency before and after CPAP therapy. RESULTS--The mean (SE) nightly CPAP run time was 4.7 (0.4) hours. There was no correlation between run time and severity of the sleep apnoea/hypopnoea syndrome as assessed by apnoea + hypopnoea frequency or multiple sleep latency, and no correlation between CPAP usage and improvement in multiple sleep latency. Thirty two patients in whom mask time was recorded had therapeutic CPAP pressures for 89% (3%) of their CPAP run times. Patients who experienced side effects from CPAP used their CPAP machines significantly less than those who did not. CONCLUSIONS--Patients with sleep apnoea/hypopnoea syndrome used CPAP for less than five hours/night on average with no correlation between severity of sleep apnoea/hypopnoea syndrome and CPAP usage. Patients who complained of side effects used their CPAP therapy less. It is recommended that, as a minimum, CPAP run time should be regularly recorded in all patients receiving CPAP therapy.     

Clinical comparison of the reusable LMA Classic laryngeal mask and the disposable Soft Seal mask in adult patients

OBJECTIVES: To compare the clinical behavior of the disposable Soft Seal laryngeal mask to the behavior of the reusable LMA Classic mask. METHODS: Patients were randomly assigned to 2 groups in which either the LMA Classic or the Soft Seal mask would be used. We assessed time required for positioning and number of attempts, seal pressure, fiberoptic bronchoscopic image, and complications. The masks were inserted by 2 anesthesiologists who were inexperienced in the use of laryngeal masks. We also compared compliance of the cuff in the laboratory. RESULTS: Sixty patients were enrolled. There were no differences in time required for insertion or number of attempts (first-try success, 83%). The mean (SD) seal pressure was greater in the Soft Seal group at 23 (4) cm H2O than in the LMA Classic group at 20 (4) cm H2O. There were no significant differences in the fiberoptic bronchoscopic images, ventilation, incidence of intraoperative complications, presence of blood on the cuff (LMA Classic, 6 out of 30 vs Soft Seal, 11 out of 29), or postoperative sore throat. In 3 patients in the Soft Seal group the laryngeal mask had to be replaced by an orotracheal tube. Cuff compliance in the laboratory was lower for the LMA Classic than for the disposable mask for all sizes assessed. CONCLUSIONS: Although the results suggest that the clinical behavior of the 2 masks is similar, the LMA Classic allowed for effective airway management in all of the cases assigned to it, whereas management was effective in 90% of the cases in which the Soft Seal mask was used. The inflatable cuff of the Soft Seal is more compliant in vitro and it provides a higher airway seal pressure than does the LMA Classic.     

慢性阻塞性肺病病人上腹部手术后鼻罩通气的应用

目的 探讨鼻罩通气在上腹部手术后的呼吸支持作用。方法 ５０例择其行上腹部手术病人,术前肺功能检查证实存在轻度中度阻塞性呼吸功能障碍,术后随机分成两组。（１）对照组：术后常规鼻导管吸氧;（２）鼻罩组：术后即开始以鼻罩行压力支持通气。观察两组病人术后通气功能及血气变化。结果 术后早期给予鼻罩通气,病人的氧合优于对照组,ＰａＣＯ２低于对照组,ＶＣ、ＦＥＶ１．０％及ＭＭＦ均明显高于对照组。结论 慢性阻塞肺     

Haemodynamic effects of pressure support and PEEP ventilation by nasal route in patients with stable chronic obstructive pulmonary disease.

BACKGROUND--Intermittent positive pressure ventilation applied through a nasal mask has been shown to be useful in the treatment of chronic respiratory insufficiency. Pressure support ventilation is an assisted mode of ventilation which is being increasingly used. Invasive ventilation with intermittent positive pressure, with or without positive end expiratory pressure (PEEP), has been found to affect venous return and cardiac output. This study evaluated the acute haemodynamic support ventilation by nasal mask, with and without the application of PEEP, in patients with severe stable chronic obstructive pulmonary disease and hypercapnia. METHODS--Nine patients with severe stable chronic obstructive pulmonary disease performed sessions lasting 10 minutes each of pressure support ventilation by nasal mask while undergoing right heart catheterisation for clinical evaluation. In random order, four sessions of nasal pressure support ventilation were applied consisting of: (1) peak inspiratory pressure (PIP) 10 cm H2O, PEEP 0 cm H2O; (2) PIP 10 cm H2O, PEEP 5 cm H2O; (3) PIP 20 cm H2O, PEEP 0 cm H2O; (4) PIP 20 cm H2O, PEEP 5 cm H2O. RESULTS--Significant increases in arterial oxygen tension (Pao2) and saturation (Sao2) and significant reductions in arterial carbon dioxide tension (PaCO2) and changes in pH were observed with a PIP of 20 cm H2O. Statistical analysis showed that the addition of 5 cm H2O PEEP did not further improve arterial blood gas tensions. Comparison of baseline values with measurements performed after 10 minutes of each session of ventilation showed that all modes of ventilation except PIP 10 cm H2O without PEEP induced a small but significant increase in pulmonary capillary wedge pressure. In comparison with baseline values, a significant decrease in cardiac output and oxygen delivery was induced only by the addition of PEEP to both levels of PIP. CONCLUSIONS--In patients with severe stable chronic obstructive pulmonary disease and hypercapnia, pressure support ventilation with the addition of PEEP delivered by nasal mask may have short term acute haemodynamic effects in reducing oxygen delivery in spite of adequate levels of SaO2.     

Prospective study of cutaneous phototoxicity after systemic hematoporphyrin derivative

Hematoporphyrin derivative (HpD) is a photoactive, oncophilic substance that produces cutaneous photosensitivity as its only significant side effect. Twenty-three patients who received systemic HpD and the usual light-avoidance precautions were studied prospectively to determine the incidence and severity of cutaneous phototoxicity (CP). Seventeen of the 23 patients (74%) reported CP, including three patients (18%) who experienced blister formation. Symptoms of CP occurred for a mean duration of 6 weeks (range 5-23 weeks). Lack of compliance with restrictive photoprotective measures was felt to be a major contributing factor. Other HpD-related complications included skin hyperpigmentation, ocular discomfort, pruritus, pain at injection site, and urticaria. CP and the restrictive measures to avoid it represent major disadvantages of the clinical use of HpD.     

Compliance at night with low flow oxygen therapy: a comparison of nasal cannulae and Venturi face masks.

BACKGROUND--The factors that influence nocturnal compliance among patients prescribed low flow oxygen therapy were determined and tolerance of nasal cannulae and Venturi face masks compared. METHODS--Two studies were performed: (1) a prospective study of 99 hospitalised patients prescribed low flow oxygen therapy, 49 on nasal cannulae and 50 on Venturi face mask; and (2) a prospective study of 20 separate patients with an acute respiratory disorder requiring low flow oxygen therapy who were given nasal cannulae and Venturi face mask on successive nights in random order. RESULTS--In study 1, 49 patients dislodged their device at least once during the night. Those using Venturi face masks and those over 75 years of age had the most dislodgements. In study 2 patients also dislodged Venturi face masks more frequently (mean (SD) 2.0 (2.4)) than nasal cannulae (0.7 (1.4)). Most patients expressed a preference for nasal cannulae. CONCLUSIONS--Nocturnal tolerance of nasal cannulae is superior to Venturi face masks, and this factor should be considered when choosing the method of oxygen delivery.     

Sleep apnea in heart transplant recipients: type, symptoms, risk factors, and response to nasal continuous positive airway pressure.

BACKGROUND: We determined the type, symptoms, and risk factors for sleep apnea in heart transplant recipients and the response to nasal continuous positive airway pressure. METHODS: A retrospective study on heart transplant recipients with sleep apnea was conducted in a tertiary care medical center with follow-up telephone interviews. Between February 1988 and August 1998, 147 patients underwent orthotopic heart transplantation at our institution. Seventeen patients (11.6%) who were suspected of having sleep apnea underwent polysomnography at a mean interval of 17.5 months after transplantation. RESULTS: All were diagnosed with sleep apnea: 13 had obstructive sleep apnea and 4 had mixed sleep apnea. Mean age at polysomnography was 50.8 years (range, 24-67 years). The patients presented with snoring (100%), excessive daytime somnolence (65%), witnessed apneas (53%), and morning fatigue (53%). Sixteen (94%) had a mean weight gain of 10.4 kg after transplantation, and 1 patient lost 14.6 kg. In the 11 patients with obstructive sleep apnea who underwent nasal continuous positive airway pressure titration, significant improvements occurred in the apnea-hypopnea index (decreased from 37.6 to 10.4; p = 0.01) and mean arousal index (decreased from 44.5 to 19.4; p = 0.01). Only 2 of the 8 patients with sleep apnea for whom nasal continuous positive airway pressure was recommended continued to use it at the time of telephone follow-up. CONCLUSIONS: Sleep apnea, especially obstructive sleep apnea, occurs frequently in heart transplant recipients. Obstructive sleep apnea appears to present in the typical manner, and although a positive response to nasal continuous positive airway pressure can be documented by polysomnography, long-term use of nasal continuous positive airway pressure may be low.     

Bilateral diaphragm paralysis after cardiac surgery with topical hypothermia.

Bilateral diaphragm paralysis is a rare but important complication of open heart surgery. Two cases were found among 360 prospectively studied patients undergoing open heart surgery during one year. Both patients had insulin dependent diabetes with peripheral neuropathy and this may have contributed to their diaphragm paralysis. The patients were studied postoperatively for one year with measurements of lung function, nocturnal oximetry, diaphragmatic function, and phrenic nerve conduction. Treatment with intermittent positive airway pressure ventilation by nasal mask was effective in both patients. After nine months one patient had recovered completely with normal phrenic nerve conduction and diaphragmatic function; the other continues most of his normal daytime activities, but still requires nasal positive airway pressure ventilation for six hours at night.     

Collapsibility of the Upper Airway during Anesthesia with Isoflurane

Background: The unprotected upper airway tends to obstruct during general anesthesia, yet its mechanical properties have not been studied in detail during this condition.

Methods: To study its collapsibility, pressure-flow relationships of the upper airway were obtained at three levels of anesthesia (end-tidal isoflurane = 1.2%, 0.8%, and 0.4%) in 16 subjects while supine and spontaneously breathing on nasal continuous positive airway pressure. At each level of anesthesia, mask pressure was transiently reduced from a pressure sufficient to abolish inspiratory flow limitation (11.8 +/- 2.7 cm H2O) to pressures resulting in variable degrees of flow limitation. The relation between mask pressure and maximal inspiratory flow was determined, and the critical pressure at which the airway occluded was recorded. The site of collapse was determined from simultaneous measurements of nasopharyngeal, oropharyngeal, and hypopharyngeal and esophageal pressures.

Results: The airway remained hypotonic (minimal or absent intramuscular genioglossus electromyogram activity) throughout each study. During flow-limited breaths, inspiratory flow decreased linearly with decreasing mask pressure (r2 = 0.86 +/- 0.17), consistent with Starling resistor behavior. At end-tidal isoflurane of 1.2%, critical pressure was 1.1 +/- 3.5 cm H2O; at 0.4% it decreased to -0.2 +/- 3.6 cm H2O (P < 0.05), indicating decreased airway collapsibility. This decrease was associated with a decrease in end-expiratory esophageal pressure of 0.6 +/- 0.9 cm H2O (P < 0.05), suggesting an increased lung volume. Collapse occurred in the retropalatal region in 14 subjects and in the retrolingual region in 2 subjects, and did not change with anesthetic depth.     

可视喉镜联合管芯和电子软镜引导经鼻气管插管用于口腔科手术患者的效果

目的评价可视喉镜联合管芯与UE电子软镜引导经鼻气管插管用于口腔科手术患者的效果。方法选取择期行全麻下经鼻气管插管手术的口腔科患者60例,ASAⅠ~Ⅱ级,年龄18~65岁,BMI<30 kg/m^2。按随机数字表法分为可视喉镜联合管芯组(K组)和UE电子软镜组(U组),每组30例。记录2组一次置入导管成功率、气管插管时间、插管并发症发生率,以及麻醉诱导前(T0)、诱导后插管前即刻(T1)、气管导管置入即刻(T2)、插管后1 min(T3)、插管后3 min(T4)的无创收缩压(SBP)、舒张压(DBP)和心率(HR)。结果 U组气管插管时间为(50.7±2.3)s,明显比K组的(55.2±1.6)s缩短,差异有统计学意义(P<0.05);2组一次插管成功率及插管时鼻咽腔出血率差异无统计学意义(P>0.05)。与T0、T1比较,2组患者T3、T4的SBP、DBP均降低,差异有统计学意义(P<0.05)。与K组比较,U组T2、T3的SBP、DBP均降低,血流动力学波动更小,差异有统计学意义(P<0.05)。结论与可视喉镜联合管芯比较,UE电子软镜快速诱导经鼻气管插管时间短、血流动力学稳定。但可视喉镜联合管芯引导经鼻插管简便、经济,值得在临床推广。     

Nasal polyposis: prevalence of positive food and inhalant skin tests.

OBJECTIVES: To investigate the etiology of nasal polyps and its relationship to allergy. The prevalence of positive food and inhalant skin tests in patients with nasal polyps and nonatopic controls was compared. STUDY DESIGN AND SETTING: Prospective controlled study in tertiary referral rhinology clinic. RESULTS: Seventy percent (70%) of the patients with nasal polyps had positive skin tests to an average of four foodstuffs, compared to 34 percent of controls (P = 0.006). Only 35 percent of the nasal polyp patients also had positive inhalant skin tests. Overall, the prevalence of positive inhalant skin tests was similar in the nasal polyp patients and controls. CONCLUSIONS: These findings suggest that the positive skin tests to foods are not merely a reflection of the general atopic status of patients with nasal polyps. It may be that non-IgE-mediated hypersensitivities, such as to ingested foods, play a role on the basis of a significant number of patients with positive intradermal skin tests to foods. SIGNIFICANCE: Evaluation of the allergic status of patients with polyposis is important. Dietary manipulation may be indicated, though its role needs further investigation.     

Influence of nasal obstruction on auto-CPAP behaviour during sleep in sleep apnoea/hypopnoea syndrome

BACKGROUND: Auto-CPAP machines have been developed to adapt automatically the positive pressure level to the required needs. The auto-CPAP response to transient nasal obstruction was tested during sleep in patients with sleep apnoea/hypopnoea syndrome (SAHS). METHODS: Nasal obstruction was induced by local instillation of histamine. Fourteen nasal challenges were performed on eight patients, seven while the patients were on the "Morphée plus" apparatus and the other seven with the patients on the "Horizon" machine. RESULTS: Nasal resistance increased initially by a mean (SD) of 166 (66)% during the trials with the "Morphée plus" and by 118 (44)% with the "Horizon" machine. The increase in nasal resistance was always accompanied by flow limitation with one exception. Mask pressure initially decreased to the minimal permitted value as nasal resistance increased with the "Morphée plus" device. A late increase of the positive pressure level occurred sometimes. Mask pressure did not change with increasing nasal resistance when the "Horizon" device was used. CONCLUSION: Neither the "Morphée plus" nor the "Horizon" device abolished flow limited breaths and resulting sleep fragmentation. We conclude that, despite the different algorithm of pressure changes, these auto-CPAP machines do not adequately respond to an acute increase in nasal resistance.     

A Comparative Trial of the Effectiveness of Nasal Interfaces Used to Deliver Continuous Positive Airway Pressure for a Brief Period in Infants With Transient Tachypnea of the Newborn

IntroductionThere is insufficient data on the effectiveness of the interfaces used for nasal continuous airway pressure (nCPAP) in newborn infants. Transpulmonary pressure (PTP) calculated from a measured esophageal pressure (Pes) could be used as a surrogate for the pressure transmitted to the distal airways during nCPAP. We aimed to compare the effectiveness of two nasal interfaces, the nasal mask and bi-nasal short prongs, during a relatively brief period of respiratory support by calculated PTP (cPTP) in infants with transient tachypnea of the newborn (TTN).MethodsNewborns with TTN who needed respiratory assistance with nCPAP were randomized to use either bi-nasal short prongs or a nasal mask. Esophageal pressure measurements were done in order to calculate PTP with either interface. The primary outcome was the cPTP transmitted with each nasal interface. Esophageal pressure measurements were recorded and PTP values were calculated from Pes measurements at the 1st, 6th, 12th and 24th hours in each patient as long as the respiratory support lasted.ResultsSixty-two newborns with TTN and on nCPAP were randomized into two groups: Group 1 to use bi-nasal short prongs (n: 31) and Group 2 to use a nasal mask (n: 31). Inspiratory and expiratory Pes and cPTP values at the 1st, 6th, 12th and 24th hours were similar with the two interfaces (P < .05).ConclusionsA nasal mask is similarly effective and safe as bi-nasal short prongs during a brief period of non-invasive respiratory support with nCPAP in late preterm and term neonates with TTN.     

Usefulness of helmet type mask in the treatment of postoperative atelectasis in a child: a case report

A 7-year-old autistic girl underwent an appendectomy under general anesthesia. Both intraoperative course and postoperative one following extubation were uneventful;however, she suddenly developed severe hypoxemia caused by massive atelectasis in the right and lower lobes 27 hours after the operation. With a helmet type mask on her face, she was successfully managed with continuous positive airway pressure (noninvasive positive pressure ventilation) mode, in which PEEP level was 5 cmH2O and FI(O2) was 0.38. Compared with the face mask type, the helmet type has the advantage of better stability on the face without losing sight, and less discomfort with fixation. In spite of a slight difficulty in setting up the device and noise to the patient, the helmet type mask seems to be more useful in the treatment of respiratory distress in pediatric patients.