Home oxygen therapy: re-thinking the role of devices

Introduction: A range of devices are available for delivering and monitoring home oxygen therapy (HOT). Guidelines do not give indications for the choice of the delivery device but recommend the use of an ambulatory system in subjects on HOT whilst walking.

Areas covered: We provide a clinical overview of HOT and review traditional and newer delivery and monitoring devices for HOT. Despite relevant technology advancements, clinicians, faced with many challenges when they prescribe oxygen therapy, often remain familiar to traditional devices and continuous flow delivery of oxygen. Some self-filling delivery-less devices could increase the users’ level of independence with ecological advantage and, perhaps, reduced cost. Some newer portable oxygen concentrators are being available, but more work is needed to understand their performances in different diseases and clinical settings. Pulse oximetry has gained large diffusion worldwide and some models permit long-term monitoring. Some closed-loop portable monitoring devices are also able to adjust oxygen flow automatically in accordance with the different needs of everyday life. This might help to improve adherence and the practice of proper oxygen titration that has often been omitted because difficult to perform and time-consuming.

Expert commentary: The prescribing physicians should know the characteristics of newer devices and use technological advancements to improve the practice of HOT.     

呼气末二氧化碳分压监测在全麻拔管后苏醒期患者中的应用

目的 探讨呼气末二氧化碳分压监测在全身麻醉拔管后苏醒期患者中的应用效果。方法 选取全身麻醉手术结束拔除气管导管转入麻醉后苏醒室观察的320例患者为研究对象,采用随机数字表法分为对照组和观察组各160例。对照组常规单孔鼻导管吸氧3 L/min并持续监测心电图、呼吸、无创血压、血氧饱和度;观察组在对照组基础上持续监测呼气末二氧化碳分压数值和波形的变化并及时给予护理干预。比较两组低氧血症发生情况、高碳酸血症和呼吸暂停检出率、面罩加压给氧率和苏醒时间。结果 观察组低氧血症程度、面罩加压给氧率显著低于对照组,高碳酸血症、呼吸暂停检出率显著高于对照组,苏醒时间显著短于对照组(P<0.05,P<0.01)。结论 对麻醉后苏醒期拔除气管插管的患者,呼气末二氧化碳分压监测可及时发现呼吸暂停、高碳酸血症等呼吸异常事件,降低低氧血症的发生率,提高麻醉苏醒的安全性,缩短苏醒时间。     

185例SARS死亡病例分析及原因探讨

目的 :回顾性分析 SARS患者死亡原因 ,为临床降低病死率提供可借鉴的经验。方法 :对 185份 2 0 0 3年 6月 2 0日源自北京市各综合医院提供上报给北京市 SARS治疗指挥中心的死亡病例资料进行回顾性分析 ,包括年龄、基础疾病、实验室检查、影像学检查以及治疗措施等。结果 :185例 SARS死亡病例中男 10 2例 ,女 83例 ;平均年龄 5 6 .4岁 ,大于 6 0岁者 85例。有基础疾病者 14 7例 (79.5 % ) ,其中心血管疾病 5 7例 ,占第一位 ;糖尿病 4 1例 ,占第二位 ;脑血管病 19例 ,占第三位 ;消化道疾病 15例。有并发症者 5 2例 (2 8.1% ) ,依次为急性呼吸窘迫综合征 (ARDS) ,继发感染 ,多脏器功能障碍综合征 (MODS)等。部分入院资料齐全者显示入院时生命体征均稳定。血液学与动脉血气分析检查显示 :疾病晚期与入院时相比 ,血糖、白细胞均升高 (P均 <0 .0 0 1) ,而淋巴细胞显著降低 (P<0 .0 0 5 ) ,动脉氧分压 (Pa O2 )、氧合指数进行性下降 (P<0 .0 0 5 ,P<0 .0 0 1) ;有近一半的患者血生化指标异常。结论 :年龄和基础疾病是 SARS死亡十分敏感的指标 ,而 SARS冠状病毒导致的肺损伤、顽固性低氧血症和高血糖代谢紊乱以及激素和抗生素的滥用所致继发感染均是 SARS患者死亡的主要原因。     

Admission respiratory status predicts mortality in COVID‐19

COVID‐19 has significant case fatality. Glucocorticoids are the only treatment shown to improve survival, but only among patients requiring supplemental oxygen. WHO advises patients to seek medical care for “trouble breathing,” but hypoxemic patients frequently have no respiratory symptoms. Our cohort study of hospitalized COVID‐19 patients shows that respiratory symptoms are uncommon and not associated with mortality. By contrast, objective signs of respiratory compromise—oxygen saturation and respiratory rate—are associated with markedly elevated mortality. Our findings support expanding guidelines to include at‐home assessment of oxygen saturation and respiratory rate in order to expedite life‐saving treatments patients to high‐risk COVID‐19 patients.     

Changes in cognitive function associated with sleep disordered breathing in older people

OBJECTIVES: Sleep disordered breathing (SDB) is very common in older people and is known to be associated with complaints of impaired daily functioning, including excessive daytime sleepiness and cognitive impairments. As part of a larger study on SDB and aging, it became possible to examine the relationship between SDB and cognition in older men and women. DESIGN: A population-based longitudinal study. SETTING: In-home interviews and home sleep recordings in the greater San Diego area. PARTICIPANTS: Community-dwelling people age 65 and older with high risk for SDB were originally studied from 1981 through 1985 and then followed every 2 years. Data from the 46 subjects who completed Visit 3 and Visit 4 are presented. MEASUREMENTS: Subjects were interviewed in the home about their sleep and medical condition before each visit. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Daytime sleepiness was based on self-report. Objective sleep was recorded in the home and scored for sleep, apneas and hypopneas, and oximetry variables. RESULTS: Increases in respiratory disturbance index (RDI) (P= .036) and increases in daytime sleepiness (P= .002) were associated with decreases in cognitive performance (i.e., increases in cognitive impairment). Increases in RDI were also associated with increases in daytime sleepiness (P= .012). Change in MMSE scores was therefore regressed onto changes in RDI, daytime sleepiness, age, and education, resulting in decreases in MMSE scores being associated with increases in daytime sleepiness (P= .019) but not with changes in RDI (P= .515). There was no significant relationship between changes in oxygen saturation levels and changes in MMSE. CONCLUSIONS: The results of this study suggest that declining cognitive function is associated primarily with increases in daytime sleepiness. Although cognitive decline was also associated with increases in RDI, this association did not hold in the more inclusive model which also included variable of SDB, oximetry, sleep and subjective report. One theoretical model could suggest that any relationship between SDB and cognitive function may be mediated by the effect of SDB on daytime sleepiness. These results suggest that older patients suffering from mild to moderate SDB may benefit from the treatment of SDB, even if they are not markedly hypoxemic.     

Early Myocardial Functional Alterations in Patients with Obstructive Sleep Apnea Syndrome

Background: There is limited information regarding myocardial alterations in patients with obstructive sleep apnea syndrome (OSAS) in the absence of pulmonary and cardiac comorbidity. In this study, we aimed to evaluate potential myocardial alterations of these patients and investigate the possible effects of OSAS-related pathological variations on left and right ventricular functions. Methods: We studied 107 consecutive patients who were referred to our sleep laboratory for clinically suspected OSAS and 30 controls without any history or symptoms of sleep-related disorders. Severity of OSAS was quantified by polysomnography. Patients with apnea–hypopnea index (AHI) < 5 were included in the OSAS (−) group (Group 1, n = 22). Subjects with AHI ≥ 5 were considered as OSAS and classified according to their AHI as mild-to-moderate (AHI ≥ 5 and AHI < 30) (Group 2, n = 45) and severe (AHI ≥ 30) OSAS groups (Group 3, n = 40). Conventional M-mode, 2D, and Doppler mitral inflow parameters, tissue Doppler velocities, myocardial peak systolic strain, and strain rate values of various segments were measured and compared between groups. Results: Patients with OSAS displayed impairment of left ventricular diastolic function compared with controls. There were no significant differences between groups regarding parameters reflecting left ventricular systolic function. Myocardial strain analysis demonstrated significant decrement regarding apical right ventricular longitudinal peak systolic strain and strain rate values between groups in relation to the severity of OSAS. Conclusions: Patients with OSAS display a regional pattern of right ventricular dysfunction correlated with the severity of disease.     

无创通气在急性左心衰并发低氧血症抢救中的应用

目的探讨无创机械通气在急性左心衰并发低氧血症抢救中的临床意义。方法对42例急性左心衰并发低氧血症的患者在常规内科治疗同时加用无创性经面罩机械通气(NIV)治疗,观察无创通气(NIV)前后患者呼吸指标、肺气体交换与心率(HR)、平均动脉压(MAP)的变化。结果42例患者均能耐受NIV治疗,临床症状明显改善,呼吸频率明显下降;与NIV治疗前相比,患者的动脉血中PH、氧分压(PaO_2)、二氧化碳分压(PaCO_2)、氧饱和度(SaO_2)等指标明显改善(P<0.05),HR与MAP明显减慢(P<0.05)。结论NIV治疗急性左心衰时能迅速改善患者的症状和低氧血症,是一种快速、安全、有效的方法,可避免气管插管。