Repeated blood gas monitoring in healthy children and adolescents by the transcutaneous route

The aim of the study was to establish transcutaneous oxygen tension (tcPO(2)), carbon dioxide tension (tcPCO(2)), and oxygen saturation (tcSO(2)) values and to investigate the intra- and interindividual variation in these values in healthy children and adolescents. Forty-one healthy children/adolescents (21 girls; mean age, 12.1 years; SD, 3.5; range, 5.0-19.0 years) participated. Continuous recordings of tcPO(2), tcPCO(2), tcSO(2), and heart rate (HR) were made for 30 min on two occasions, with a mean interval of 10.3 days, with the child/adolescent in a sitting position. The respiratory rate (RR) was counted manually during the last 5 min of each recording. The mean values of tcPO(2), tcPCO(2), tcSO(2), HR, and RR during the last 5 min of the recordings were reported. At the first recording, the mean value for tcPO(2) was 10.8 kPa (SD 1.0), for tcPCO(2) 5.1 kPa (0.4), for tcSO(2) 97.4% (1.1), for HR 82.2 min(-1) (9.9), and for RR 19.0 min(-1) (2.8). The coefficient of variation for tcPO(2) was 9.3%, for tcPCO(2) 7.8%, for tcSO(2) 1.1%, for HR 12.0%, and for RR 14.7%. The mean intraindividual variation in tcPO(2) was 0.3 kPa (SD 1.0), tcPCO(2) 0.0 kPa (0.5), tcSO(2) 0.1% (1.3), HR 0.1 min(-1) (7.7), and RR 0.5 min(-1) (2.7). No significant differences were observed in tcPO(2), tcPCO(2), tcSO(2), HR, or RR between the two recordings. In conclusion, the reproducibility of tcPO(2), tcPCO(2), and tcSO(2) monitoring during 30 min in healthy children and adolescents was good. This indicates that transcutaneous blood gas monitoring may be used to document significant changes in blood gas tensions and oxygen saturation over time.     

Evaluation of transcutaneous CO2 responses following acute changes in PaCO2 in healthy subjects

Background and objective: Transcutaneous blood gas‐monitoring systems with miniaturized SpO₂ (peripheral blood oxygen saturation)/PCO₂ combined sensors (TOSCATM) have been widely used. There are no reports of the inter‐ and intra‐individual variability in transcutaneous measurements of PaCO₂ (PtcCO₂) in response to acute progressive changes in PaCO₂. This study examined inter‐ and intra‐individual variability of PtcCO₂ measurements under semi‐steady‐state conditions, and characterized the behaviour of PtcCO₂ in response to acute progressive changes in PaCO₂. Methods: Subjects breathed mixed gases through a mouthpiece connected to an automatic arterial blood gas controller. Using end‐tidal PCO₂ and PO₂ as guides, PaCO₂ was controlled to increase and/or decrease between baseline and ≥ 60 mm Hg, in a stepwise (n = 9) or progressive fashion (n = 6). Arterial blood was sampled when needed. Results: Intra‐individual correlation coefficients between PtcCO₂ and PaCO₂ were excellent in all subjects (0.971–0.989); however, the slope of the regression line varied among subjects (1.040–1.335). Bias and limits of agreement (± 2 SD from bias) between PtcCO₂ and PaCO₂ were ?1.8 mm Hg and ?7.7 to 4.1 mm Hg. Changes in PtcCO₂ in response to acute progressive changes in PaCO₂ also varied among subjects. Conclusion: The PtcCO₂ measurement system allows reliable estimation of PaCO₂ in a given subject. However, caution is needed when comparing absolute values between subjects or when acute changes in PaCO₂ occur.     

社区老年糖尿病患者足背经皮氧分压现况研究

目的观察分析社区2型糖尿病(T2DM)患者足背经皮氧分压(TcPO2)水平。方法选择在北京市方庄和望京社区卫生服务中心就诊的T2DM且无糖尿病足患者270例,分别测量入选患者左、右侧足背TcPO2,并且以TcPO260mm Hg(1mm Hg=0.133kPa)为界,将至少一侧足背TcPO2<60 mm Hg为降低组214例(79.3%),其余为正常组56例。收集2组患者相关资料,进行二分类logistic回归分析。结果与正常组比较,降低组女性(61.2%vs 35.7%,P=0.001)和双下肢感觉异常(35.0%vs 17.9%,P=0.014)比例更高、高血压病程[(15.8±11.7)年vs(11.2±7.6)年,P=0.029]和血脂异常时间[(9.9±7.4)年vs(7.7±5.1)年,P=0.048]更长,差异有统计学意义。二分类logistic回归分析显示,女性(OR=2.831,95%CI:1.517~5.285,P=0.001)和双下肢感觉异常(OR=2.229,95%CI:1.047~4.748,P=0.038)为患者TcPO2降低的影响因素。结论社区老年T2DM无糖尿病足患者的足背TcPO2降低发生率高,TcPO2可能发现患者亚临床的足部组织灌注改变状况。     

呼气末二氧化碳监测在慢性阻塞性肺疾病中的应用

目的研究在慢性阻塞性肺疾病(COPD)患者中使用CO2监测仪测得参数与动脉血气参数的相关性,探讨其临床实用价值。方法用CO2监测仪测定68例COPD患者的呼气末二氧化碳分压(PETCO2)、脉搏血氧饱和度(SpO2),同步测定动脉血气参数动脉二氧化碳分压(PaCO2)和动脉血氧饱和度(SaO2)以比较差异。结果①COPD患者经CO2监测仪所测得PETCO2、SpO2与动脉血气参数PaCO2、SaO2存在线性相关性,其回归方程如下:SpO2和SaO2(Y=3.415+0.895X,r=0.824,P0.001)、PETCO2和PaCO2(Y=6.876+1.032X,r=0.723,P0.001);②COPD患者无合并呼吸衰竭时PETCO2和PaCO2较合并呼吸衰竭相关性好。结论 PETCO2可以作为一种快速、无创的监测指标应用于COPD。     

Assessing the accuracy of the OMRON HEM‐907XL oscillometric blood pressure measurement device in patients with nondialytic chronic kidney disease

The OMRON HEM?907XL is a commercial oscillometric blood pressure (BP) monitor that was used in the Systolic Blood Pressure Intervention Trial (SPRINT), in which 28% of participants had chronic kidney disease (CKD). This study examined the accuracy of the monitor in nondialytic patients with CKD. Eighty‐seven patients met inclusion criteria. The authors used a modified Association for the Advancement of Medical Instrumentation (AAMI) protocol, with one observer recording measurements from the monitor and two blinded physicians obtaining simultaneous aneroid values by auscultation. Using AAMI method 1, there was a 2.5±9.5 mm Hg difference in OMRON and aneroid systolic BP, and a ?1.6±6.5 mm Hg difference in diastolic BP. Using AAMI method 2, there was a 5.1±7.4 mm Hg difference in systolic BP and a ?0.2±5.4 mm Hg difference in diastolic BP. In patients with CKD, the OMRON HEM‐907XL appears to be accurate for measuring diastolic BP, but did not perform as well for systolic BP.     

Optimizing respiratory function assessments to elucidate the impact of obesity on respiratory health

There is an increasing prevalence of obesity worldwide and its impact on respiratory health is of significant concern. Obesity affects the respiratory system by several mechanisms, including by direct mechanical changes due to fat deposition in the chest wall, abdomen and upper airway, as well as via systemic inflammation. The increased mechanical load in obese individuals leads to reduced chest wall and lung compliance and increased work of breathing. While there is generally minimal effect on spirometric values, as body mass index increases, the expiratory reserve volume, and hence functional residual capacity, reduces, often approaching residual volume in more severe obesity. The majority of evidence however suggests that obese individuals free from lung disease have relatively normal gas exchange. The link between asthma and obesity, while initially unclear, is now recognized as being a distinct asthma phenotype. While studies investigating objective markers of asthma have shown that there is no association between obesity and airway hyper‐responsiveness, a recent working group identified obesity as a major risk factor for the development of asthma in all demographic groups. Although the temptation may be to attribute obesity as the cause of dyspnoea in symptomatic obese patients, accurate respiratory assessment of these individuals is necessary. Lung function tests can confirm that any altered physiology are the known respiratory consequences of obesity. However, given that obesity causes minimal changes in lung function, significant abnormalities warrant further investigation. An important consideration is the knowledge that many of the respiratory physiology consequences of obesity are reversible by weight loss.     

Respiratory disease and respiratory physiology: Putting lung function into perspective interstitial lung disease

The interstitial lung diseases pathologically involve the pulmonary interstitium but may also involve the airways, pleura and pulmonary circulation. They may be idiopathic, be part of other conditions, or be related to drug or environmental exposures. This review will focus on diagnostic and prognostic information provided by lung function tests in the idiopathic interstitial pneumonias, particularly idiopathic pulmonary fibrosis and non‐specific interstitial pneumonia. These disorders are characterized by small stiff lungs with impaired gas exchange. Lung function tests, particularly lung volumes and gas transfer, used initially on patient presentation and then repeatedly on follow up, together with high‐resolution computed tomography scans, can generate predictive formulae which are superior to single tests and can be used to provide useful information to assess the natural history of the disease or guide therapy. The concomitant presence of emphysema may mask the degree of restriction and may have adverse prognostic implications when accompanied by pulmonary hypertension.     

Evaluation of a transcutaneous carbon dioxide monitor ("TOSCA") in adult patients in routine respiratory practice

BACKGROUND: Non-invasive measurement of oxygenation is routine in adult clinical practice but transcutaneous monitoring of PCO(2) (PtcCO(2)) is used much less due to technical difficulties with earlier transcutaneous electrodes. OBJECTIVE: Our aim was to determine the reliability of estimating arterial PCO(2) (PaCO(2)) using a recently introduced combined SaO(2)/PtcCO(2) monitor ("TOSCA", Linde Medical Systems) in adult patients in routine clinical respiratory practice. METHODS: PtcCO(2) was measured in patients requiring arterial blood gases for clinical reasons. Ten minutes after the probe had been attached to an earlobe PtcCO(2) was recorded, immediately before arterial blood sampling. The PCO(2) values obtained were compared by Bland-Altman analysis. RESULTS: Samples were taken from 48 unselected patients with varied pathology. There were no technical problems. Median age was 56 years (range 20-86 years). The mean difference between PaCO(2) and PtcCO(2) was -0.04kPa, sd of the difference 0.67kPa. Bland-Altman analysis showed generally good agreement between the two measurements across the range of PaCO(2) values (4-10.9kPa). Four of 48 measurements showed a PCO(2) difference >1kPa with no technical or clinical explanations apparent. CONCLUSIONS: The accuracy of estimation of PaCO(2) by the TOSCA transcutaneous electrode was generally good and the device appears promising for use in routine clinical respiratory practice.     

High flow nasal cannula versus noninvasive ventilation in the treatment of acute hypercapnic respiratory failure: A systematic review and meta-analysis

Chronic obstructive pulmonary disease can lead to acute hypercapnic respiratory failure (AHRF), often treated using noninvasive ventilation (NIV). Emerging research suggests the potential utility of high flow nasal cannula (HFNC) for AHRF. This systematic review and meta-analysis aimed to determine the effect of HFNC versus NIV on AHRF management. A search of electronic databases (CINAHL, MEDLINE, and Academic Search Complete), web sources, and trial registries was last conducted on 9 February 2023. Quality and risk of bias assessments were conducted. Meta-analyses were used to synthesise data. Seven randomised controlled trials were included. No statistically significant differences between HFNC and NIV were found within the following outcomes of interest: (i) correction of pCO2: standardised mean difference (SMD) = −0.16, 95% confidence interval (CI) (−0.34 to 0.02), p = 0.08; (ii) correction of pH: SMD = −0.05, 95% CI (−0.25 to 0.14), p = 0.59; (iii) correction of pO2: SMD = −0.15, 95% CI (−0.40 to 0.09), p = 0.22; (iv) intubation rates: risk ratio (RR) = 0.87, 95% CI (0.41 to 1.82), p = 0.71; (v) mortality rates: RR = 0.85, 95% CI (0.47 to 1.56), p = 0.61; and (vi) treatment switch: RR = 1.30, 95% CI (0.43 to 3.94), p = 0.64. More controlled trials with large sample sizes are required to investigate the management of AHRF of various aetiologies. HFNC may be used as a final exhaustive measure for COPD-related AHRF where NIV is not tolerated, and when it is not clinically indicated to extend to endotracheal intubation.     

Cold air challenge of airway reactivity in children: a correlation of transcutaneously measured oxygen tension and conventional lung functions

For pharmacological challenges, a correlation between the induced changes of the transcutaneously measured oxygen tension (PtcO2) and of conventional pulmonary function tests (PFTs) has been documented. We performed a 4-minute cold air challenge (CACh) in 17 children with bronchial asthma under continuous monitoring of PtcO2, and correlated observed changes with CACh-induced alterations of conventional PFTs. PtcO2 decreased significantly with CACh (from 86 +/- 10 mmHg to 66 +/- 14 mmHg, P less than 0.001), but returned to near-baseline within the next 30 minutes. PFTs changed with a similar pattern; the closest correlation was found between the CACh-induced fall of PtcO2 and Delta-FEV1 (r = 0.833, P less than 0.001). Changes of FVC, PEF, and Vmax50 correlated significantly as well. PtcO2 can complement or substitute for conventional PFTs in assessing the response to CACh in children.     

无创呼吸机治疗COPD伴重度CO2潴留的疗效观察

目的探讨无创机械通气在慢性阻塞性肺病伴重度CO2潴留患者中的治疗效果。方法回顾性分析2005年12月到2007年10月我科收治的30例COPD病人资料,均为PaCO2〉80mmHg的COPD伴Ⅱ型呼衰患者,在常规药物治疗及氧疗基础上应用无创呼吸机辅助通气（NIPPV）治疗,通过自身对照观察患者NIPPV治疗前、后血气指标变化和病情改善程度。结果30例患者中2例不能耐受无创通气,放弃治疗,24例使用无创后好转,病情稳定出院,4例无创通气失败,改行气管插管,死亡2例。NIPPV治疗有效患者2h后血气指标明显改善,PaCO2显著下降（P〈0．001）,48h后病情明显好转。结论无创正压机械辅助通气可显著改善COPD伴重度高碳酸血症患者,疗效肯定。     

Detection of respiratory syncytial virus (RSV) at birth in a newborn with respiratory distress

Respiratory syncytial virus (RSV) is the most common respiratory pathogen in infants and young children. From the nasopharyngeal or conjunctival mucosa of infected individuals, RSV spreads to the lower respiratory tract causing acute bronchiolitis and pneumonia after an incubation period of 4‐6 days. In addition to its well‐documented tropism for the airway epithelium, it has been shown previously that RSV can also spread hematogenously and efficiently infect extrapulmonary tissues of human hosts. Furthermore, it has been shown in animal models that RSV can spread transplacentally from the respiratory tract of a pregnant mother to the lungs of the fetus. This report describes a documented case of neonatal RSV infection strongly suggestive of prenatal transmission of this infection in humans from an infected mother to her offspring.

     

血气分析中二氧化碳分压、乳酸对老年慢性阻塞性肺病急性加重期预后的影响

目的观察血气分析中二氧化碳分压(PaCO₂)、乳酸对老年慢性阻塞性肺病急性加重期(exacerbation of chronic obstructive pulmonary disease, AECOPD)预后的影响效果。 方法回顾性分析重庆市第十三人民医院2018年6月至2019年6月呼吸内科收治的150例老年AECOPD患者临床资料,依据患者预后分为死亡组15例以及存活组135例,对两组治疗前后PaCO₂、乳酸进行对比,利用Pearson相关性分析法对老年AECOPD预后与血气分析中PaCO₂、乳酸相关性进行检验。 结果治疗前两组PaCO₂、乳酸无明显统计学差异(P>0.05),治疗后存活组较治疗前下降,存在统计学差异(P<0.05),死亡组较治疗前无统计学差异(P>0.05),存活组均低于死亡率,存在统计学差异(P<0.05);Pearson相关性分析结果提示,老年AECOPD患者预后与PaCO₂、乳酸均呈负相关性(r＝-0.56、-0.61,P<0.05)。 结论血气分析中PCO₂、乳酸与老年AECOPD患者预后呈负相关性,数值越高预后越差。     

经皮二氧化碳分压在早产儿无创呼吸机治疗中的应用

目的探讨经皮二氧化碳分压监测在早产儿无创呼吸机治疗中的应用,并探讨与患儿动脉血气分析的相关性。方法选取2018年3月-2019年2月收治的80例新生儿重症监护室早产儿,根据呼吸功能分为呼吸障碍组(A组62例)和非呼吸障碍组(B组18例),根据出生体质量分为极低出生体质量组(C组29例)和非极低出生体质量组(D组51例);分别采用经皮氧和二氧化碳分压监测仪、动脉血气分析仪检测经皮氧分压(TcPO 2)、经皮二氧化碳分压(TcPCO 2)、动脉氧分压(PaO 2)及动脉二氧化碳分压(PaCO 2),比较A组与B组、C组与D组通气2 h、24 h时TcPO 2与PaO 2及TcPCO 2与PaCO 2水平;采用Pearson相关系数法分析通气2 h、24 h时TcPO 2与PaO 2及TcPCO 2与PaCO 2的相关性;绘制受试者工作特征曲线(ROC),分析TcPO 2与TcPCO 2对治疗期间低氧血症、高碳酸血症及低碳酸血症的诊断效能。结果A组与B组、C组与D组无创通气治疗2 h、24 h时TcPO 2低于PaO 2,TcPCO 2高于PaCO 2,差异均有统计学意义(P<0.05);Pearson相关性分析显示,无创通气治疗2 h、24 h时TcPO 2与PaO 2、TcPCO 2与PaCO 2均呈正相关(P<0.001)。以PaO 2<80 mmHg为低氧血症诊断标准,通气2 h、24 h低氧血症发生率分别为68.75%、11.25%,TcPO 2对通气2 h时诊断低氧血症的灵敏度、特异度、准确度及ROC下面积(AUC)为94.55%、98.00%、92.50%、0.901;通气24 h时为88.89%、98.59%、97.50%、0.937。以PCO 2>45 mmHg、PCO 2<35 mmHg分别为高碳酸血症及低碳酸血症诊断标准,通气2 h高碳酸血症发生率为48.75%,无低碳酸血症,通气24 h高碳酸血症、低碳酸血症发生率分别为12.50%、3.75%;TcPCO 2对通气2 h时诊断高碳酸血症的灵敏度、特异度、准确度及AUC为97.87%、95.12%、95.00%、0.922;通气24 h时诊断高碳酸血症的灵敏度、特异度、准确度及AUC为100.00%、97.14%、97.50%、0.950,低碳酸血症为100.00%、98.70%、98.75%、0.971。结论TcPO 2、TcPCO 2监测可准确评估早产儿PaO 2、PaCO 2,且对早产儿无创呼吸机治疗期间低氧血症、高碳酸血症及低碳酸血症有较高诊断价值。