Continuous positive airway pressure and mechanical ventilation by facemask in newborn infants.

During a nine-month period 24 newborn infants were treated with continuous positive airway pressure (CPAP) or mechanical ventilation delivered through a facemask. The mask was held in place in a way that minimised trauma and distortion of the head. The median birth weight of the infants was 1096 g and their median gestational age 29 weeks.The usual reason for treatment was hyaline membrane disease or recurrent apnoea due to inadequate control of breathing. Twenty-one of the infants survived. The technique was simple to apply and complications were minimal. We suggest that it may have advantages over other methods of applying CPAP or mechanical ventilation to infants mildly affected by respiratory illnesses and that it should be useful in avoiding endotracheal intubation or reducing the length of time that infants with more serious illnesses are intubated.     

Determinants of skin contact pressure formation during non-invasive ventilation

There is no published data about mask features that impact skin contact pressure during mask ventilation.To investigate the physical factors of skin contact pressure formation.We measured masks with original and reduced air cushion size and recorded contact pressure. We determined cushion contact and mask areas by planimetric measurements.Contact pressures necessary to prevent air leakage during inspiration exceed inspiratory pressure by 1.01±0.41 hPa independent of cushion size.Contact area, ventilator pressure and mask area during inspiration and expiration impact contact pressure. Mask contact pressures are higher during expiration. The contact pressure increases with increase in inspiratory pressures independent of the ventilator cycle. During expiration, the contact pressure will increase in proportion to the expiratory pressure reduction of the ventilator. The mask with reduced air cushion size developed higher contact pressures.Contact pressure can be reduced by selecting masks with a small mask area in combination with a large mask cushion.     

老年手术患者应用丙泊酚复合瑞芬太尼喉罩麻醉的临床效果观察

目的：探讨靶控输注丙泊酚复合瑞芬太尼喉罩麻醉在老年手术患者中的临床应用效果,为临床麻醉提供参考。方法：选取127例老年手术患者作为研究对象,随机分为A、B、C3组,A组43例（采用瑞芬太尼复合丙泊酚麻醉,喉罩通气）、B组42例（采用丙泊酚麻醉,喉罩通气）,C组42例（采用瑞芬太尼复合丙泊酚麻醉,面罩通气）,均采用靶控输注静脉麻醉法。观察麻醉诱导时间、术中反应、麻醉效果、镇静效果评分、苏醒时间、认知功能以及不良反应发生率等指标。结果：丙泊酚总用量：A组为（335．2±56．4）mg,B组为（466．5±64．8）mg,C组为（334．8±59．7）mg,经方差分析,差异有统计学意义,F=6．513,P〈0．05;Ramsay评分：A组6分的例数为37例（86．0％）,B组为30（71．4％）,C组为34（81．0％）,经卡方检验,差异有统计学意义,X^2=5．832,P〈0．05;不良反应发生率：A组为5例（11．6％）,B组为15例（35．7％）,C组为7例（16．7％）,经卡方检验,差异有统计学意义,X^2=7．546,P〈0．05。结论：老年手术患者应用丙泊酚复合瑞芬太尼喉罩麻醉效果显著,安全有效。     

Noninvasive positive-pressure ventilation in acute respiratory failure

Noninvasive positive-pressure ventilation is a type of mechanical ventilation that does not require an artificial airway. Studies published in the 1990s that evaluated the efficacy of this technique for the treatment of diseases as chronic obstructive pulmonary disease, congestive heart failure and acute respiratory failure have generalized its use in recent years. Important issues include the selection of the ventilation interface and the type of ventilator. Currently available interfaces include nasal, oronasal and facial masks, mouthpieces and helmets. Comparisons of the available interfaces have not shown one to be clearly superior. Both critical care ventilators and portable ventilators can be used for noninvasive positive-pressure ventilation; however, the choice of ventilator type depends on the patient''s condition and therapeutic requirements and on the expertise of the attending staff and the location of care. The best results (decreased need for intubation and decreased mortality) have been reported among patients with exacerbations of chronic obstructive pulmonary disease and cardiogenic pulmonary edema.Noninvasive positive-pressure ventilation is the delivery of mechanical ventilation to patients with respiratory failure without the requirement of an artificial airway. The key change that led to the recent increase in the use of this technique occurred in the early 1980s with the introduction of the nasal continuous positive airway pressure mask for the treatment of obstructive sleep apnea. Studies published in the 1990s that evaluated the efficacy of noninvasive positive-pressure ventilation for treatment of diseases such as chronic obstructive pulmonary disease, congestive heart failure and acute respiratory failure have generalized its use in recent years.¹ In 1998, an international study on the use of mechanical ventilation found that 5% of patients admitted to intensive care units received noninvasive positive-pressure ventilation.²Noninvasive positive-pressure ventilation includes various techniques for augmenting alveolar ventilation without an endotracheal airway. The clinical application of noninvasive ventilation by use of continuous positive airway pressure alone is referred to as “mask CPAP,” and noninvasive ventilation by use of intermittent positive-pressure ventilation with or without continuous positive airway pressure is called noninvasive positive-pressure ventilation.     

Effect of inspiratory resistance to prolonged exercise in a hot environment wearing protective clothing

The effects of inspiratory resistance on prolonged work in a hot environment wearing a nuclear, bacteriological and chemical warfare (NBCW) mask and overgarment were assessed in 10 males. Subjects walked on a treadmill at 5 km/hr, 2% gradient, until their core temperature reached 39° C or for a duration of 90 min. Rectal temperature, heart rate, ventilation, oxygen consumption and rate of perceived breathing were measured. There were no differences between break-point time without the canister (62.2 ± 21 min) and with the canister (58.9 ± 17 min). Regression analysis indicated that the mean core temperature increased by 0.02° C for every minute of work performed and heart rate by 6 beats/min for every increase of 0.2° C in core temperature. Reduction in heat transfer brought about by wearing the protective overgarment and mask with or without the canister will significantly increase core temperature and limit the performance of moderate work to approximately 1 h in a moderately fit individual.     

Non-invasive mechanical ventilation for acute respiratory failure.

The value of mechanical ventilation using intermittent positive pressure ventilation delivered non-invasively by nasal mask was assessed in six patients with life threatening exacerbations of chronic respiratory disease. Median (range) arterial oxygen and carbon dioxide tensions were 4.4 (3.5-7.2) kPa and 8.7 (5.5-10.9) kPa respectively, with four patients breathing air and two controlled concentrations of oxygen. The arterial oxygen tension increased with mechanical ventilation to a median (range) of 8.7 (8.0-12.6) kPa and the carbon dioxide tension fell to 8.2 (6.5-9.2) kPa. Four patients discharged after a median of 10 (8-17) days in hospital were well five to 22 months later. One died at four days of worsening sputum retention and another after five weeks using the ventilator for 12-16 hours each day while awaiting heart-lung transplantation. This technique of mechanical ventilation avoids endotracheal intubation and can be used intermittently. Hypercapnic respiratory failure can be relieved in patients with either restrictive or obstructive lung disease in whom controlled oxygen treatment results in unacceptable hypercapnia. Respiratory assistance can be tailored to individual need and undertaken without conventional intensive care facilities.     

Evaluation on masks with exhaust valves and with exhaust holes from physiological and subjective responses

The purpose of this study was to compare the effects of wearing different kinds of masks on the ear canal temperature, heart rate, clothing microclimate, and subjective perception of discomfort. Ten subjects performed intermittent exercise on a treadmill while wearing the protective masks in a climatic chamber controlled at an air temperature of 25 degrees C and a relative humidity of 70%. Two types of mask-mask A, with exhaust valves and mask B, with exhaust holes-were used in the study. The results of this study indicated: (1) The subjects had a tendency toward lower maximum heart rate when wearing mask A than when wearing mask B. (2) Temperatures and absolute humidities (the outer surface of mask, the microclimate inside the mask, the chest wall skin and microclimate) of mask A were significantly lower than those of mask B. (3) The ear canal temperature increased significantly in mask B as compared to that in mask A. (4) The ear canal temperature showed significant augmentation along with increased temperature and humidity inside the mask microclimate. The mask microclimate temperature also affected significantly the chest microclimate temperature. (5) Mask A was rated significantly lower for perception of humidity, heat, breath resistance, tightness, unfitness, odor, fatigue, and offered less overall discomfort than mask B. (6) Subjective preference for mask A was higher. (7) The ratings of subjective overall discomfort showed significant augmentation along with increased wetness and fatigue. We discuss how the ventilation properties of masks A and B induce significantly different temperature and humidity in the microclimates of the masks and the heat loss of the body, which have profound influences on heart rate, thermal stress, and subjective perception of discomfort.     

Novel Vitamin and Gold-Loaded Nanofiber Facial Mask for Topical Delivery

l-ascorbic acid has been widely used in cosmetic and dermatological products because of its ability to scavenge free radicals and destroy oxidizing agents. However, it is chemically unstable and can easily be oxidized. The current cosmetic facial masks available in the market are pre-moistened, which means that the aqueous fluid content of the mask may oxidize some of the unstable active ingredients such as ascorbic acid. This work presents an anti-wrinkle nanofiber face mask containing ascorbic acid, retinoic acid, gold nanoparticles, and collagen. This novel face mask will only be wetted when applied to the skin, thus enhancing product stability. Once moistened, the content of the mask will gradually dissolve and release the active ingredients and ensure maximum skin penetration. The high surface area-to-volume ratio of the nanofiber mask will ensure maximum contact with the skin surface and help to enhance the skin permeation to restore its healthy appearance. Electrospun fiber mats may provide an attractive alternative to the commercial facial cotton masks.     

A Novel Rescue Technique for Difficult Intubation and Difficult Ventilation

We describe a novel non surgical technique to maintain oxygenation and ventilation in a case of difficult intubation and difficult ventilation, which works especially well with poor mask fit.Can not intubate, can not ventilate" (CICV) is a potentially life threatening situation. In this video we present a simulation of the technique we used in a case of CICV where oxygenation and ventilation were maintained by inserting an endotracheal tube (ETT) nasally down to the level of the naso-pharynx while sealing the mouth and nares for successful positive pressure ventilation.A 13 year old patient was taken to the operating room for incision and drainage of a neck abcess and direct laryngobronchoscopy. After preoxygenation, anesthesia was induced intravenously. Mask ventilation was found to be extremely difficult because of the swelling of the soft tissue. The face mask could not fit properly on the face due to significant facial swelling as well. A direct laryngoscopy was attempted with no visualization of the larynx. Oxygen saturation was difficult to maintain, with saturations falling to 80%. In order to oxygenate and ventilate the patient, an endotracheal tube was then inserted nasally after nasal spray with nasal decongestant and lubricant. The tube was pushed gently and blindly into the hypopharynx. The mouth and nose of the patient were sealed by hand and positive pressure ventilation was possible with 100% O₂ with good oxygen saturation during that period of time. Once the patient was stable and well sedated, a rigid bronchoscope was introduced by the otolaryngologist showing extensive subglottic and epiglottic edema, and a mass effect from the abscess, contributing to the airway compromise. The airway was secured with an ETT tube by the otolaryngologist.This video will show a simulation of the technique on a patient undergoing general anesthesia for dental restorations.Download video file.^{(28M, mov)}     

喉罩与气管插管在呼吸衰竭患者院前和急诊急救中的应用效果比较

目的:探讨喉罩与气管插管在呼吸衰竭患者院前和急诊急救中的应用效果。方法:选择2016年1月至2018年5月由中国人民解放军第174医院急诊医学科出诊抢救的呼吸衰竭患者92例,所有患者根据通气方法的不同分为A组和B组。其中A组使用喉罩人工通气方法进行急救,共有47例,而B组则使用气管插管人工通气方法进行急救,共有45例,比较两组患者治疗前与治疗1 h后呼吸频率(RR)、心率(HR)以及血氧饱和度(SpO_2)等生命体征指标,对比喉罩与气管插管置入时间、一次性成功率、心肺复苏成功率情况,记录两组并发症发生情况。结果:两组患者治疗前HR、RR以及SpO_2比较差异无统计学意义(P0.05),两组患者治疗1 h后HR、RR均较治疗前降低,SpO_2较治疗前升高(P0.05),两组患者治疗1h后HR、RR以及SpO_2比较差异无统计学意义(P0.05)。A组的喉罩插管置入时间明显短于B组的气管插管置入时间,且A组插管一次性成功率明显高于B组,两组比较差异具有统计学意义(P0.05),而两组心肺复苏成功率比较差异无统计学意义(P0.05)。A组并发症发生率为2.13%(1/47),低于B组的并发症发生率13.33%(6/45),差异具有统计学意义(P0.05)。结论:喉罩通气与气管插管通气效果基本一致,但其操作更简单更安全,可缩短插管置入时间,提高一次性成功率,争取抢救时间。     

A new airway device for small laboratory animals

There is a need for a device for improved management of the airway of small laboratory animals during general anaesthesia. This report introduces such a device, referred to here as the airway device (AD). The AD has some similarity to the laryngeal mask airway (LMA) developed for human patients, but the mask portion of the device is specifically designed for small laboratory animals. In addition, the device has an oesophageal extension and unlike the LMA does not have a cuff associated with the mask. This report also shares experience of tests of one prototype AD with six New Zealand white rabbits. The AD was used for administering isoflurane and its effectiveness was evaluated during conditions of spontaneous and controlled intermittent positive pressure ventilation. The results provide encouragement for further development of the AD for airway management of small laboratory animals.     

Transient ventilatory response to CO2 as a function of sleep state in full-term infants

The influence of sleep state on the transient (i.e., initial 60 s) and steady-state ventilatory responses to 2% CO2 inhalation was studied in 19 healthy full-term infants. A nasal mask pneumotachometer was used to measure ventilation and end-tidal CO2 partial pressure (PCO2) and enabled abrupt changes in the inspired gas concentration to be made. The magnitude of the change in minute ventilation for both the transient and steady-state responses to CO2 was not statistically different between active (AS) and quiet (QS) sleep. Nonetheless the greater variability in minute ventilation during AS compared with QS continued throughout the period of CO2 inhalation and was associated with a more variable change in ventilation in the individual infants during AS. There was a greater increase in end-tidal PCO2 over the first 60 s during AS (3.3 +/- 0.3 vs. 2.6 +/- 0.2 Torr, in AS and QS, respectively, P less than 0.03). This may indicate a smaller initial increase in alveolar ventilation, relative to CO2 delivery to the lungs, in response to CO2 inhalation during AS. Asynchronous chest wall movements were more common during AS than QS (P less than 0.005) and did not change with CO2. The inconsistent transient ventilatory response to CO2 during AS compared with QS may be important in the behavior of infants to spontaneous episodes of hypercapnia occurring during AS.     

Lung function in diaphragm pacing.

Electric stimulation of the diaphragm via the phrenic nerve to induce ventilation has recently been used for the long-term management of chronic ventilatory insufficiency. Since 1973 three patients with inadequate alveolar ventilation have been treated with diaphragm pacing at the Toronto Western Hospital. Two, who had quadriplegia due to lesions of the spinal cord in the upper cervical region and a severe restrictive ventilatory defect, were treated with continuous diaphragm pacing. The third patient required assisted nocturnal ventilation because of primary alveolar hypoventilation. All three patients tolerated the diaphragm pacing well, and pulmonary function tests showed satisfactory gas exchange with the patients breathing room air. This form of therapy seems to be a practical clinical method of managing chronic ventilatory failure in patients with lesions of the upper cervical cord or primary alveolar hypoventilation.     

Two-Minute Training for Improving Neonatal Bag and Mask Ventilation

Objectives

To test effectivity of a two-minute training consisting of a few key-points in ventilation using the self-inflating bag (SIB).

Study Design

Experienced and inexperienced caregivers were asked to mask ventilate a leak free manikin using the SIB before and after the training. Mask leak and pressures were measured using respiratory function monitoring. Pressures above 35 cm H₂O were considered excessive. Parameters were compared using a Wilcoxon non-parametric test.

Results

Before and after the short training, experienced caregivers had minimal median (IQR) mask leak (14 (3-75) vs. 3 (0-53)%; p<0.01). Inexperienced users had large leak which reduced from 51 (7-91)% before to 11 (2-71)% after training (p<0.01). Pressures above 35 cm H₂O hardly occurred in experienced caregivers (0 (0-5) vs. 0 (0-0)%; ns). In inexperienced caregivers this frequently occurred but decreased considerably after training (94 (46-100) vs. 2 (0-70)%; p<0.01).

Conclusion

A two-minute training of bag and mask ventilation was effective. This training could be incorporated into any training program.     

End-tidal CO2 response to low levels of inspired CO2 in awake beagle dogs

The steady-state end-tidal CO2 tension (PCO2) was examined during control and 1% CO2 inhalation periods in awake beagle dogs with an intact airway breathing through a low dead-space respiratory mask. A total of eight experiments were performed in four dogs, comprising 31 control observations and 23 CO2 inhalation observations. The 1% inhaled CO2 produced a significant increase in the steady-state end-tidal PCO2 comparable to the expected 1 Torr predicted from conventional CO2 control of ventilation. We conclude that 1% inhaled CO2 results in a hypercapnia. Any protocol that is to resolve the question of whether mechanisms are acting during low levels of inhaled CO2 such that ventilation increases without any change in arterial PCO2 must have sufficient resolving power to discriminate changes in gas tension in magnitude predicted from conventional (i.e., arterial PCO2) control of ventilation.     

Laryngeal response to nasal ventilation in nonsedated newborn lambs.

Although endoscopic studies in adult humans have suggested that laryngeal closure can limit alveolar ventilation during nasal intermittent positive pressure ventilation (nIPPV), there are no available data regarding glottal muscle activity during nIPPV. In addition, laryngeal behavior during nIPPV has not been investigated in neonates. The aim of the present study was to assess laryngeal muscle response to nIPPV in nonsedated newborn lambs. Nine newborn lambs were instrumented for recording states of alertness, electrical activity [electromyograph (EMG)] of glottal constrictor (thyroarytenoid, TA) and dilator (cricothyroid, CT) muscles, EMG of the diaphragm (Dia), and mask and tracheal pressures. nIPPV in pressure support (PS) and volume control (VC) modes was delivered to the lambs via a nasal mask. Results show that increasing nIPPV during wakefulness and quiet sleep led to a progressive disappearance of Dia and CT EMG and to the appearance and subsequent increase in TA EMG during inspiration, together with an increase in trans-upper airway pressure (TUAP). On rare occasions, transmission of nIPPV through the glottis was prevented by complete, active glottal closure, a phenomenon more frequent during active sleep epochs, when irregular bursts of TA EMG were observed. In conclusion, results of the present study suggest that active glottal closure develops with nIPPV in nonsedated lambs, especially in the VC mode. Our observations further suggest that such closure can limit lung ventilation when raising nIPPV in neonates.     

Human breathing patterns on mouthpiece or face mask during air, CO2, or low O2

Steady-state breathing patterns on mouthpiece and noseclip (MP) and face mask (MASK) during air and chemostimulated breathing were obtained from pneumotachometer flow. On air, all 10 subjects decreased frequency (f) and increased tidal volume (VT) on MP relative to that on MASK without changing ventilation (VE), mean inspiratory flow (VT/TI), or mean expiratory flow (VT/TE). On elevated CO2 and low O2, MP exaggerated the increase in VE, f, and VT/TE due to profoundly shortened TE. On elevated CO2, MASK exaggerated VT increase with little change in f. Increased VE and VT/TI were thus due to increased VT. During low O2 on MASK, both VT and f increased. During isocapnia, shortened TE accounted for increased f; during hypocapnia, increased f was related primarily to shortened TI. Thus the choice of a mouthpiece or face mask differentially alters breathing pattern on air and all components of ventilatory responses to chemostimuli. In addition, breathing apparatus effects are not a simple consequence of a shift from oronasal to oral breathing, since a noseclip under the mask did not change breathing pattern from that on mask alone.     

Cyanide Self-poisoning

Four cases of cyanide self-poisoning were admitted to one hospital over a period of two years. Two of the patients died. The diagnosis in the unconscious patient may be suggested by the finding of bradycardia and the absence of cyanosis (despite inadequate ventilation). The diagnosis can be confirmed in 5 to 10 minutes by a simple test on gastric aspirate, performed by the casualty officer. Cardiac pacing was used in two patients and may have a place in the supportive management of severe cases.     

Current status of long term ventilation of children in the United Kingdom: questionnaire survey

ObjectivesTo identify the number and current location of children, aged 0 to 16 years, requiring long term ventilation in the United Kingdom, and to establish their underlying diagnoses and ventilatory needs.DesignPostal questionnaires sent to consultant respiratory paediatricians and all lead clinicians of intensive care and special care baby units in the United Kingdom.SubjectsAll children in the United Kingdom who, when medically stable, continue to need a mechanical aid for breathing.Results141 children requiring long term ventilation were identified from the initial questionnaire. Detailed information was then obtained on 136 children from 30 units. Thirty three children (24%) required continuous positive pressure ventilation by tracheostomy over 24 hours, and 103 received ventilation when asleep by a non-invasive mask (n=62; 46%), tracheostomy (n=32; 24%), or negative pressure ventilation (n=9; 7%). Underlying conditions included neuromuscular disease (n=62; 46%), congenital central hypoventilation syndrome (n=18; 13%), spinal injury (n=16; 12%), craniofacial syndromes (n=9; 7%), bronchopulmonary dysplasia (n=6; 4%), and others (n=25; 18%). 93 children were cared for at home. 43 children remained in hospital because of home circumstances, inadequate funding, or lack of provision of home carers. 96 children were of school age and 43 were attending mainstream school.ConclusionsA significant increase in the number of children requiring long term ventilation in the United Kingdom has occurred over the past decade. Contributing factors include improved technology, developments in paediatric non-invasive ventilatory support, and a change in attitude towards home care. Successful discharge home and return to school is occurring even for severely disabled patients. Funding and home carers are common obstacles to discharge.

Key messages

• The number of children requiring long term ventilatory support has increased substantially in the past 8 years
• Ventilatory support at home is the best option for meeting the child’s psychological needs and enhancing quality of life
• The majority of children dependent on long term ventilation live at home and attend mainstream schools
• A shift of care has occurred from intensive care units to less acute areas

     

Cardiac and respiratory activity at arousal from sleep under controlled ventilation conditions.

Arousal from sleep is associated with elevated cardiac and respiratory activity. It is unclear whether this occurs because of homeostatic mechanisms or a reflex activation response associated with arousal. Cardiorespiratory activity was measured during spontaneous arousals from sleep in subjects breathing passively on a ventilator. Under such conditions, homeostatic mechanisms are eliminated. Ventilation, end-tidal PCO2, mask pressure, diaphragmatic electromyograph, heart rate, and blood pressure were measured in four normal subjects under two conditions: assisted ventilation and a normal ventilation control condition. In the control condition, there was a normal, sleep-related fall in ventilation and rise in end-tidal PCO2. Subsequently, at an arousal, there was an increase in respiratory and cardiac activity. In the ventilator condition, a vigorous cardiorespiratory response to a spontaneous arousal from sleep remained. These results indicate that sleep-related respiratory stimuli are not necessary for the occurrence of elevated cardiorespiratory activity at an arousal from sleep and are consistent with the hypothesis that such activity is at least in part due to a reflex activation response.