PaCO2 Levels Research Articles

The level of partial pressure of carbon dioxide affects respiratory effort in COVID-19 patients undergoing pressure support ventilation with extracorporeal membrane oxygenation

BackgroundPatients with COVID-19 undergoing pressure support ventilation (PSV) with extracorporeal membrane oxygenation (ECMO) commonly had high respiratory drive, which could cause self-inflicted lung injury. The aim of this study was to evaluate the influence of different levels of partial pressure of carbon dioxide(PaCO2) on respiratory effort in COVID-19 patients undergoing PSV with ECMO.MethodsECMO gas flow was downregulated from baseline (respiratory rate < 25 bpm, peak airway pressure < 25 cm H2O, tidal volume < 6 mL/kg, PaCO2 < 40 mmHg) until PaCO2 increased by 5 − 10 mmHg. The pressure muscle index (PMI) and airway pressure swing during occlusion (ΔPOCC) were used to monitor respiratory effort, and they were measured before and after enforcement of the regulations.ResultsTen patients with COVID-19 who had undergone ECMO were enrolled in this prospective study. When the PaCO2 increased from 36 (36 − 37) to 42 (41–43) mmHg (p = 0.0020), there was a significant increase in ΔPOCC [from 5.6 (4.7–8.0) to 11.1 (8.5–13.1) cm H2O, p = 0.0020] and PMI [from 3.0 ± 1.4 to 6.5 ± 2.1 cm H2O, p < 0.0001]. Meanwhile, increased inspiratory effort determined by elevated PaCO2 levels led to enhancement of tidal volume from 4.1 ± 1.2 mL/kg to 5.3 ± 1.5 mL/kg (p = 0.0003) and respiratory rate from 13 ± 2 to 15 ± 2 bpm (p = 0.0266). In addition, the increase in PaCO2 was linearly correlated with changes in ΔPOCC and PMI (R2 = 0.7293, p = 0.0003 and R2 = 0.4105, p = 0.0460, respectively).ConclusionsIn patients with COVID-19 undergoing PSV with ECMO, an increase of PaCO2 could increase the inspiratory effort.

Effects of restrictive fluid resuscitation on the clinical efficacy of treating traumatic hemorrhagic shock combined with traumatic coagulopathy

This study aims to assess the clinical efficacy of limited fluid resuscitation on traumatic hemorrhagic shock combined with traumatic coagulopathy. A cohort of 120 patients with traumatic hemorrhagic shock complicated with traumatic coagulopathy at admission were divided into two groups based on their emergency fluid resuscitation: the study group (received restrictive fluid resuscitation) and the control group (received conventional fluid resuscitation). Then, the incidence of complications, coagulation parameters, blood gas parameters and electrolyte parameters between the two groups were compared. The incidence of complications in the study group was 6.67%, which was significantly lower than the 20.00% observed in the control group (p &lt; 0.05). Before resuscitation, there was no significant difference in coagulation parameters, blood gas parameters and electrolyte parameters between the two groups (p &gt; 0.05), and in both groups, before and after resuscitation, the coagulation parameters after resuscitation were higher than those before resuscitation, blood gas parameters were lower than those before resuscitation, Mg2+, Cl− and Na+ levels were higher than those before resuscitation, K+ was lower than that before resuscitation, and the difference had statistical significance (p &lt; 0.05). After resuscitation, the coagulation parameters in the study group were significantly lower than those in the control group, the BL (Blood Lactic Acid) and PaCO2 (partial pressure of carbon dioxide in arterial blood) levels in the study group were lower than those in the control group, the BE (base excess) and PaO2 levels were higher than those in the control group, and the differences were statistically significant (p &lt; 0.05). However, after resuscitation, we found no significant difference in electrolyte parameters between both groups (p &gt; 0.05). Restrictive fluid resuscitation was found to significantly enhance coagulation and blood gas function, stabilize water and electrolyte balance and reduce complications in traumatic hemorrhagic shock patients complicated with traumatic coagulopathy. These findings hold substantial clinical significance and merit further exploration.

Efficacy of noninvasive ventilator treatment in patients with severe chronic obstructive pulmonary disease (COPD) type II respiratory failure.

To investigate the efficacy of noninvasive ventilator usage for type II respiratory failure in patients with severe chronic obstructive pulmonary disease (COPD). A total of 124 patients with COPD complicated with type II respiratory failure were divided into an observation group (n = 63) and a control group (n = 61) according to their intervention protocols. The patients in the observation group received noninvasive ventilator intervention, and the patients in the control group received bronchodilators, cough suppressants, oxygen therapy, anti-infection medications, nutritional support, and correction of electrolyte imbalances. Lung function indexes, arterial blood gas index, and inflammatory indicators were collected to assess the efficacy of noninvasive ventilator treatment in patients with severe COPD and type II respiratory failure. The levels of FEV1, FEV1/FVC and FEV1% of the two groups after treatment were significantly higher than those before treatment (P<0.05), with significantly higher levels in the observation group than the control group (all P<0.05). Post-treatment levels of PaCO2 decreased significantly while the post-treatment levels of PaO2 increased significantly (all P<0.05). Additionally, the levels of WBC, CRP and PCT of the control group was significantly higher than that of the observation group after treatment (all P<0.05). Noninvasive ventilator treatment can improve hypoxemia, improve lung function and reduce inflammatory responses in patients with COPD complicated with type II respiratory failure, suggesting its potential for wider clinical application.

Correlations of IL-1β and vitamin D with CAT score in patients with acute exacerbation of chronic obstructive pulmonary disease.

This study was to analyze the correlations of IL-1β and vitamin D (VitD) with chronic obstructive pulmonary disease assessment test (CAT) score in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). For this purpose, a total of 65 patients with chronic obstructive pulmonary disease (COPD) treated in our hospital between June 2020 and June 2022 were enrolled and assigned to a research group, and 40 healthy individuals who underwent physical examination in our hospital over the same time spanning were enrolled into the control group. The 65 COPD patients were further grouped into a stability group (30 cases) and an exacerbation group (35 cases). The two groups were compared in the levels of 25-hydroxyvitamin D (25(OH)D), interleukin-1β (IL-1β) and blood gas indexes (arterial carbon dioxide partial pressure (PaCO2) and arterial partial pressure of oxygen (PaO2). The modified Medical Research Council Dyspnea Scale (mMRC) and the CAT were adopted for evaluation of the stability group and exacerbation group. The correlations of IL-1β and 25(OH)D with mMRC and CAT scores were analyzed. The diagnostic value of IL-1β and VitD in patients in different stages was analyzed through receiver operating characteristic (ROC) curves. Results showed that the control group showed greatly lower IL-1β and PaCO2 levels and higher 25(OH)D and PaO2 levels than the research group (all P<0.05). The stability group got greatly lower mMRC and CAT scores than the exacerbation group (both P<0.05). IL-1β had positive correlations with mMRC and CAT scores, while 25(OH)D had negative correlations with them (P<0.05). According to ROC curve-based analysis, IL-1β and 25(OH)D had areas under the curves of 0.814 and 0.583, respectively, in diagnosing the acute exacerbation period, and had specificities of 56.67% and 43.33%, respectively and sensitivities of 97.14% and 74.29%, respectively. In conclusion, patients with COPD have increased IL-1 β and VitD deficiency, so VitD can be properly supplemented during treatment, and the levels of inflammatory factors should be paid close attention to at all times. IL-1 β and VitD can be regarded as novel ideas for the diagnosis and treatment of COPD, which may further improve the effect of COPD prevention and treatment.

CORRELATION BETWEEN END-TIDAL CO2 AND ABGS PaCO2 IN NEONATES ON MECHANICAL VENTILATION

Monitoring arterial blood gases (ABGs) is essential for neonates requiring mechanical ventilation. End-tidal CO2 (EtCO2) emerges as a promising alternative for long-term monitoring due to its less intrusive and faster measurement. However, the relationship between EtCO2 and ABGs PaCO2 in mechanically ventilated neonates remains unclear. This study aims to ascertain the reliability of EtCO2 as a surrogate marker for ABGs PaCO2 in neonates on mechanical ventilation at Combine Military Hospital (CMH) Rawalpindi. This prospective observational study was conducted at CMH Rawalpindi between October 15, 2022, and July 15, 2023. The study included 100 neonates in the CMH Rawalpindi Neonatal Intensive Care Unit (NICU) requiring mechanical ventilation within the first 28 days of life. ABG blood samples were collected at predefined intervals, and capnography assessed EtCO2. The association between ABGs PaCO2 and EtCO2 was evaluated using Pearson's correlation coefficient. The study cohort comprised 52 male and 48 female neonates with an average age of 4.7 days, all undergoing mechanical ventilation. ABGs and EtCO2 were monitored for up to 24 hours, revealing a significant positive association between ABGs PaCO2 and EtCO2 (P &lt; 0.01, Pearson's correlation value = 0.82). The Bland-Altman plot indicated a mean bias of -2.3 mmHg with limits of agreement from -8.1 to 3.5. The association remained consistent across age, sex, and respiratory distress severity. In neonates receiving mechanical ventilation at CMH Rawalpindi, EtCO2 and ABGs PaCO2 exhibit a positive correlation. EtCO2 emerges as a potentially reliable option for quick and less invasive monitoring of PaCO2 levels in this population.

Association between the first 24 hours PaCO2 and all-cause mortality of patients suffering from sepsis-associated encephalopathy after ICU admission: A retrospective study.

The relationship between the levels of the first 24-h PaCO2 and the prognosis of sepsis-associated encephalopathy (SAE) remains unclear, and the first 24-h optimal target for PaCO2 is currently inconclusive. This study was performed to investigate the correlation between PaCO2 and all-cause mortality for SAE patients, establish a reference range of the initial 24-hour PaCO2 for clinicians in critical care, and explain the possible pathophysiological mechanisms of abnormal PaCO2 levels as a higher mortality risk factor for SAE. The baseline information and clinical data of patients were extracted from the fourth edition Medical Information Mart for Intensive Care database (MIMIC-IV 2.0). Multivariate logistic regressions were performed to assess the relationship between PaCO2 and all-cause mortality of SAE. Additionally, restricted cubic splines, Kaplan-Meier Survival analyses, propensity score matching (PSM) analyses, and subgroup analyses were conducted. A total of 5471 patients were included in our cohort. In the original and matched cohort, multivariate logistic regression analysis showed that normocapnia and mild hypercapnia may be associated with a more favorable prognosis of SAE patients, and survival analysis supported the findings. In addition, a U-shaped association emerged when examining the initial 24-hour PaCO2 levels in relation to 30-day, 60-day, and 90-day mortality using restricted cubic splines, with an average cut-off value of 36.3mmHg (P for nonlinearity<0.05). Below the cut-off value, higher PaCO2 was associated with lower all-cause mortality, while above the cut-off value, higher PaCO2 was associated with higher all-cause mortality. Subsequent subgroup analyses revealed similar results for the subcohort of GCS≤8 compared to the original cohort. Additionally, when examining the subcohort of GCS>8, a L-shaped relationship between PaCO2 and the three clinical endpoints emerged, in contrast to the previously observed U-shaped pattern. The findings from the subcohort of GCS>8 suggested that patients experiencing hypocapnia had a more unfavorable prognosis, which aligns with the results obtained from corresponding multivariate logistic regression analyses. The retrospective study revealed the association between the first 24-h PaCO2 and all-cause mortality risk (30-day, 60-day, and 90-day) for patients with SAE in ICU. The range (35mmHg-50mmHg) of PaCO2 may be the optimal target for patients with SAE in clinical practice.

Prehospital Advanced Airway Management and Ventilation for Out-of-Hospital Cardiac Arrest with Prehospital Return of Spontaneous Circulation: A Prospective Observational Cohort Study in Japan

Background The relationship among advanced airway management (AAM), ventilation, and oxygenation in patients with out-of-hospital cardiac arrest (OHCA) who achieve prehospital return of spontaneous circulation (ROSC) has not been validated. This study was designed to evaluate ventilation and oxygenation for each AAM technique (supraglottic devices [SGA] or endotracheal intubation [ETI]) using arterial blood gas (ABG) results immediately after hospital arrival. Methods This observational cohort study, using data from the Japanese Association for Acute Medicine OHCA Registry, included patients with OHCA with prehospital and hospital arrival ROSC between July 1, 2014, and December 31, 2019. The primary outcomes were the partial pressure of carbon dioxide in the arterial blood (PaCO2) and partial pressure of oxygen in the arterial blood (PaO2) in the initial ABG at the hospital for each AAM technique (SGA or ETI) performed by paramedics. The secondary outcome was favorable neurological outcome (cerebral performance category [CPC] 1 or 2) for specific PaCO2 levels, which were defined as good ventilation (PaCO2 ≤45 mmHg) and insufficient ventilation (PaCO2 >45 mmHg). Results This study included 1,527 patients. Regarding AAM, 1,114 and 413 patients were ventilated using SGA and ETI, respectively. The median PaCO2 and PaO2 levels were 74.50 mmHg and 151.35 mmHg in the SGA group, while 66.30 mmHg and 173.50 mmHg in the ETI group. PaCO2 was significantly lower in the ETI group than in the SGA group (12.55 mmHg; 95% CI 15.27 to 8.20, P-value < 0.001), while no significant difference was found in PaO2 by multivariate linear regression analysis. After stabilizing inverse probability of weighting (IPW), the adjusted odds ratio for favorable neurological outcome at 1 month was significant in the good ventilation group compared to the insufficient ventilation cohort (adjusted odds ratio = 2.12, 95%CI: 1.40 to 3.19, P value < 0.001). Conclusion The study showed that in OHCA patients with prehospital ROSC, the PaCO2 levels in the initial ABG were lower in the group with AAM by ETI than in the SGA group. Furthermore, patients with prehospital ROSC and PaCO2 ≤45 mmHg on arrival had an increased odds of favorable neurological outcome after stabilized IPW adjustment.

Knock-down of IGFBP2 ameliorates lung fibrosis and inflammation in rats with severe pneumonia through STAT3 pathway

Objective To observe the mechanism of IGFBP2 knock-down in improving lung fibrosis and inflammation through STAT3 pathway in rats with severe pneumonia. Materials and Methods First, SP rat model was established. Then rats were divided into the Control group, the SP group, the SP + Lv-vector shRNA group, the SP + Lv-IGFBP2 shRNA group, the SP + Lv-vector group, and the SP + Lv-IGFBP2 group. The mRNA and protein levels of IGFBP2, NOS, CD206 and Arg 1 were detected by RT-qPCR and Western blot. IHC was used to check the positive expression of IGFBP2 and MCP1. A fully automated blood gas analyzer was used to detected PaCO2, CO2 content, PaO2 and SaO2. HE and Masson staining were performed to observe the lung tissue injury and collagen deposition of rats in each group. ELISA assays were used to calculate the levels of inflammatory factors IL-1β, IL-6, TNF-α, IL-4, and IL-10. Flow cytometry was conducted to acquire the ratio of M1-type AMs and M2-type AMs. Results Compared with the Control group, IGFBP2, iNOS, CD206, and Arg1 mRNA and protein expression levels, IGFBP2 and MCP1 positive expressions, PaCO2, p-STAT3/STAT3, p-JAK2/JAK2, IL-1β, IL-6, and TNF-α levels, the number of AMs and neutrophils, the proportion of M1 type AMs and the expressions of α-SMA, Collagen-I, Collagen III, and Fibronectin were significantly increased in SP rats (p < 0.05), while PaCO2, CO2, and SaO2, IL-4 and IL-10 levels, and the proportion of M2 type AMs decreased (p < 0.05). However, the knockdown of IGFBP2 reversed the above index trends. Conclusion Knock-down of IGFBP2 ameliorated lung injury in SP rats, inhibited inflammation and pulmonary fibrosis, and promoted M2-type transformation of AMs by activating the STAT3 pathway.

Intraoperative partial pressure of arterial carbon dioxide levels and adverse outcomes in patients undergoing lung transplantation

ObjectivePatients undergoing lung transplantation (LTx) often experience abnormal hypercapnia or hypocapnia. This study aimed to investigate the association between intraoperative PaCO2 and postoperative adverse outcomes in patients undergoing LTx. MethodsWe retrospectively reviewed the medical records of 151 patients undergoing LTx. Patients’ demographics, perioperative clinical factors, and pre- and intraoperative PaCO2 data after reperfusion were collected and analyzed. Based on the PaCO2 levels, patients were classified into three groups: hypocapnia (≤35 mmHg), normocapnia (35.1–55 mmHg), and hypercapnia (>55 mmHg). Univariate and multivariable logistic regressions were used to identify independent risk factors for postoperative composite adverse events and in-hospital mortality. ResultsIntraoperative hypercapnia occurred in 69 (45.7%) patients, and hypocapnia in 17 (11.2%). Patients with intraoperative PaCO2 of 35.1–45 mmHg showed a lower incidence of composite adverse events (53.3%) and mortality (6.2%) (P < 0.001). There was no significant difference in composite adverse events and mortality among preoperative PaCO2 groups (P > 0.05). Compared with intraoperative PaCO2 at 35.1–45 mmHg, the risk of composite adverse events in hypercapnia group increased: the adjusted OR was 3.07 (95% confidence interval [CI]: 1.36–6.94; P = 0.007). The risk of death was significantly higher in hypocapnia group than normocapnia group, the adjusted OR was 7.69 (95% CI: 1.68–35.24; P = 0.009). Over ascending ranges of PaCO2, PaCO2 at 55.1–65 mmHg had the strongest association with composite adverse events, the adjusted OR was 6.40 (95% CI: 1.18–34.65; P = 0.031). ConclusionThese results demonstrate that intraoperative hypercapnia independently predicts postoperative adverse outcomes in patients undergoing LTx. Intraoperative hypocapnia shows predictive value for postoperative in-hospital mortality in LTx.

Correlation of Serum Clara Cell Secretory Protein 16, Plasma Fibrinogen and Serum Amyloid A with the Severity of Acute Exacerbated COPD and Their Combination in Prognosis Assessment.

Chronic obstructive pulmonary disease (COPD) has tremendous detrimental effects on patients' quality of life, lung function, disease progression and socioeconomic burden. This study aimed to investigate new serum biomarkers for COPD detection. Three recently emerging biomarkers, including Clara cell secretory protein⁃16 (CC16), plasma fibrinogen (FIB) and serum amyloid A (SAA), were investigated for their potential in stratifying the severity of COPD. A total of 220 patients with AECOPD were recruited. Multivariate logistical regression was used to analyze odds ratios of an array of characteristic of patients, including age, global initiative for chronic obstructive lung disease (GOLD), diabetes mellitus, heart diseases, PaCO2, CC16, FIB, and SAA. Correlations of CC16, FIB and SAA levels to each other, GOLD, and PaCO2 were also measured using Spearman correlation. Receiver operating characteristic (ROC)/curve analysis was used to assess sensitivity and specificity of CC16, FIB, SAA and the combination of the three markers in identifying AECOPD patients with poor prognosis. Our data suggested that age, GOLD, diabetes mellitus, heart diseases, PaCO2, CC16, FIB, and SAA are all significant risk factors for poor prognosis of AECOPD. CC16, FIB and SAA were positively correlated to each other and to GOLD and PaCO2 levels. CC16, FIB and SAA all had a high sensitivity and specificity in identifying patients with a poor prognosis. CC16, FIB and SAA are new markers with potentially high predictive value in AECOPD. Our data support further development of these biomarkers to improve clinical management of AECOPD through providing more accurate prognosis of AECOPD patients that enable timely adjustment of treatment plans.

CD4+ T cells related to disease severity in elderly and frailty community-acquired pneumonia patients: A retrospective cohort study.

Elderly and frailty individuals show a more senescent immune system, which may relate to worse outcome in community-acquired pneumonia (CAP). This study aimed to explore prognostic factors related to immune. Sixty of elderly (≥65 years) and frailty (clinical frailty scale ≥5 scores) nonsevere CAP patients and 60 severe CAP (SCAP) patients were recruited at our center. Clinical and laboratory data, and several assessment scores were collected. Compared with nonsevere CAP group, the elderly and frailty SCAP patients showed higher level of BMI, PaCO2 and lactate in arterial blood-gas, CURB-65 score, ICU admission, mechanical ventilation, shock accidence, and longer hospital stay using two-tailed t test. The SCAP group also showed increased CRP, IL-6, and PCT, and decreased CD3+ T cells, CD4+ T cells, and CD8+ T cells. Logistic regression analysis showed that CD4+ T cells, IL-6 and PCT were independent prognostic factors for SCAP. The area under the receiver operating characteristic (ROC) curve for CD4+ T cells combined with PCT was 0.771 (95% CI 0.683-0.859), and the sensitivity and specificity were both 76.7%. Paired t test analysis showed that low CD4+ T cells in SCAP patients increased after treatment. CD4+ T cells decreased in elderly and frailty SCAP patients, and CD4+ T cells combined with PCT were relatively accurate in the prediction of elderly and frailty SCAP.

Effect of different analgesic treatments on the pulmonary function in elderly hip fracture patients: A prospective study.

To investigate the effect of different analgesic methods on lungs in elderly patients with hip fractures. A prospective study was conducted on 78 elderly hip fracture patients undergoing spinal anesthesia for surgery, where 3 analgesic methods were used: postoperative Patient-controlled intravenous analgesia pump (PCIA) (group I), pre and postoperative PCIA (group II), and preoperative fascia iliaca compartment block (FICB) + postoperative PCIA (group III). The following indicators were monitored at admission (T1), on the day of surgery before anesthesia (T2), and 7 days after surgery (T3): heart rate (HR), respiratory rate (RR), forced expiratory volume during the first second, arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2), C-reactive protein (CRP), and interleukin 6 (IL-6). Pulmonary complications such as pulmonary atelectasis and respiratory insufficiency were analyzed. The HR, RR, forced expiratory volume during the first second, PaO2, PaCO2, IL-6, and CRP levels at T1 after fracture did not significantly differ among the 3 groups (P > .05). After different analgesic treatments post-admission, all indicators at T2 were significantly higher in group I than in groups II and III (P < .05), while there was no significant difference between groups II and III (P > .05). At T3, there were no significant differences in RR, HR, PaO2, PaCO2, and CRP levels among the groups (P > .05), but IL-6 levels at T3 were significantly higher in group I than in groups II and III (P < .05). The use of effective pain relief during surgery can help protect the lung function of elderly patients with hip fractures. When using PCIA with FICB before surgery, respiratory performance may be better protected compared to using unsustained analgesia. This could be due to a decrease in the levels of inflammatory markers such as CRP and interleukin-6.

Prognostic value of oxygen inhalation therapy for simple nocturnal hypoxemia in COPD: a meta-analysis.

Objective: The effect of oxygen therapy on the prognosis of chronic obstructive pulmonary disease (COPD) with nocturnal hypoxemia (NOD) has been controversial. Therefore, this study systematically evaluated the relevant literature and included it into randomized controlled studies for meta-analysis to evaluate the efficacy and prognosis. Methods: We searched PubMed, EMBASE, web of science, Cochrane, China HowNet and Wanfang database for the literature on the prognosis of COPD patients with simple NOD from the establishment of the database to 30 June 2022. The outcome indicators were death and aggravation of the disease. The efficacy evaluation measures were pulmonary function and arterial blood gas results. The publication bias and heterogeneity of the included studies were evaluated. Results: A total of 621 patients from 5 studies were included in this meta-analysis, and there was no publication bias in the included studies. The total mortality of long-term oxygen therapy (LTOT) in COPD patients with simple NOD in oxygen therapy group (RR = 1.04; 95% CI: 0.81-1.33, p = 0.77), mortality (RR = 0.87; 95% CI: 0.58-1.31, p = 0.50), risk of progression to LTOT events (RR = 1.07; 95% CI: 0.76-1.51, p = 0.71). PaO2 in patients with COPD and simple NOD in oxygen therapy group was higher than that in non-oxygen therapy group (mean difference (MD) = 13.47; 95% CI: 3.49-23.46, p = 0.008), the decrease of PaCO2 level was not statistically significant (MD = -10.05; 95% CI: -26.36-6.27, p = 0.23). Conclusion: Oxygen therapy can improve the prognosis of blood oxygen partial pressure in COPD patients with simple NOD, but oxygen therapy has no significant effect on the survival rate, controlling the progression of the disease to LTOT and reducing the partial pressure of carbon dioxide.

Safety and Effectiveness of Carbon Dioxide Removal CO2RESET Device in Critically Ill Patients.

In this retrospective study, we report the effectiveness and safety of a dedicated extracorporeal carbon dioxide removal (ECCO2R) device in critically ill patients. Adult patients on mechanical ventilation due to acute respiratory distress syndrome (ARDS) or decompensated chronic obstructive pulmonary disease (dCOPD), who were treated with a dedicated ECCO2R device (CO2RESET, Eurosets, Medolla, Italy) in case of hypercapnic acidemia, were included. Repeated measurements of CO2 removal (VCO2) at baseline and 1, 12, and 24 h after the initiation of therapy were recorded. Over a three-year period, 11 patients received ECCO2R (median age 60 [43-72] years) 3 (2-39) days after ICU admission; nine patients had ARDS and two had dCOPD. Median baseline pH and PaCO2 levels were 7.27 (7.12-7.33) and 65 (50-84) mmHg, respectively. With a median ECCO2R blood flow of 800 (500-800) mL/min and maximum gas flow of 6 (2-14) L/min, the VCO2 at 12 h after ECCO2R initiation was 157 (58-183) mL/min. Tidal volume, respiratory rate, and driving pressure were significantly reduced over time. Few side effects were reported. In this study, a dedicated ECCO2R device provided a high VCO2 with a favorable risk profile.

Retrospective cohort study of pulmonary arterial hypertension associated with connective tissue disease effect on patients' prognosis.

The objectives of this study are to clarify clinical characteristics and recognize prognostic factors of CTD-PAH patients. A retrospective cohort study of consecutive patients with documented CTD-PAH diagnosis from Jan 2014 to Dec 2019 was conducted, the ones who have other comorbid conditions that cause PH were excluded. Survival functions were plotted using the Kaplan-Meier method. Univariable and multivariable Cox regression analysis was applied to determine the survival-related factors. In 144 patients with CTD-PAH analyzed, the median sPAP value was 52.5 (44.0, 71.0) mmHg, the overall targeted drug usage rate was 55.6%, and only 27.5% patients were given combination. Twenty-four non-PAH-CTD patients with sPAP value were included as the control group. Compared with non-PAH-CTD groups, CTD-PAH patients had worse cardiac function, higher NT-pro BNP and γ-globulin level, and lower PaCO2 level. Compared with the mild PAH group, the moderate-severe PAH group had worse cardiac function; increased Hb, HCT, and NP-pro BNP level; and decreased PaO2. Kaplan-Meier analysis showed significant difference for survival among non-PAH-CTD, mild CTD-PAH, and moderate-severe CTD-PAH groups. The univariate analyses showed that Hb, pH, and Ln (NT-pro BNP) were identified as factors significantly associated with survival, and Hb and pH showed significant association with risk of death in the multivariate model. Kaplan-Meier analysis also showed that Hb > 109.0 g/L and pH > 7.457 affected CTD-PAH patients' survival significantly. PAH is not rare in CTDs patients; PAH affects CTD patients' prognosis significantly. Higher Hb and pH were associated with an increased risk of death. Key Points • Pulmonary arterial hypertension affects connective tissue disease patients' prognosis significantly. • The significantly factors associated with survival is hemoglobin, pH, and Ln (NT-pro BNP).

Impact of pharmacological and non-pharmacological interventions on mortality in chronic obstructive pulmonary disease (COPD) patients

PurposeThis review aimed to summarise evidence about the impact of pharmacological and non-pharmacological interventions on survival in COPD patients. MethodsWe performed a narrative literature review on the effect of pharmacological and non-pharmacological interventions on survival in COPD patients. ResultsInhaled therapies are central to reduce symptoms in COPD. In particular, inhaled steroids seem to have the greatest effect on mortality. Despite the anti-inflammatory effects attributed to statins, their benefit in COPD has been shown only in cases of combined cardiovascular diseases. The use of beta-blockers in COPD has not been associated with increased COPD-related mortality and a beneficial effect on all-cause mortality has even been shown in COPD patients with cardiovascular diseases. Influenza and pneumococcal vaccination reduced the occurrence of exacerbations and mortality due to COPD. In addition, long-term oxygen therapy (LTOT) (≥15h/day) in COPD patients with severe hypoxemia had a positive effect on survival. Regarding non-pharmacological interventions, it has been demonstrated that smoking cessation, treatment compliance and nutritional supplementation for underweight patients also have a positive effect on survival. Non-invasive ventilation results were dependent on patient PaCO2 levels. In patients with advanced COPD, further prospective studies are needed to know the effect of bronchoscopic lung volume reduction and lung transplant on COPD survival. Regarding lung transplant, a survival benefit in patients with a pre-transplant BODE score of ≥7 has been shown in retrospective studies. ConclusionMost of the studies did not evaluate survival as the main criteria and further long-term studies on the global management of COPD are required.

Pressure versus volume-controlled ventilation with BASKA mask airway in laparoscopic cholecystectomy: A randomized clinical study

ABSTRACT Background The best ventilation mode that suits with LMAs is still unclear. In this study, we investigated the ventilatory performance of Baska masks in patients who underwent elective laparoscopic cholecystectomy under general anaesthesia and pneumoperitoneum with either volume-controlled ventilation (VCV) or pressure-controlled ventilation (PCV) mode. Methods Fifty-Six patients with ASA I – II, who underwent laparoscopic cholecystectomy, were randomly classified into VCV (n = 28) and PCV (n = 28) groups. The lung was ventilated with a tidal volume of 8 ml/kg in the VCV group. It was ventilated initially using an inflating pressure that delivered a tidal volume of 8 ml/kg with a maximum of 35 cmH2O in the PCV group. The primary outcome was the intraoperative oropharyngeal leak pressure (OLP) of the Baska mask. Secondary outcomes were intraoperative lung mechanics, arterial carbon dioxide levels, and perioperative adverse effects. Results After pneumoperitoneum inflation, the OLP, peak inflation pressure (PIP), mean pressure (Pmean), PaCO2, and end-tidal CO2 significantly increased, and the calculated dynamic compliance significantly decreased in both ventilation modes. All variables partially returned to baseline after pneumoperitoneum deflation. Patients ventilated with PCV mode demonstrated significantly lower PIP and PaCO2 levels but higher dynamic compliance with statistically comparable OLP-PIP difference and higher leak fraction. Conclusion In this study, Patients ventilated with PCV mode showed lower PIP and PaCO2 but higher dynamic compliance, and higher leak fraction. However, both modes investigated provided effective Baska mask ventilation and maintained the OLP throughout the procedure with a statistically comparable OLP-PIP difference.

PaCO2 Levels at Admission Influence the Prognosis of Sepsis Patients: A Nonlinear Relationship

ABSTRACT Background: Sepsis is a life-threatening organ dysfunction caused by a maladjusted host response to infection (Sequential Organ Failure Assessment [SOFA] ≥ 2). PaCO2 is a blood gas that is commonly tested in hospitalized patients. Few studies have investigated how abnormal PaCO2 levels influence the prognosis of sepsis patients. Methods: A retrospective study was applied to data on sepsis patients extracted from the MIMIC-III public database and the results of their first PaCO2 examination after admission. The outcome measure was all-cause death within 90 days of follow-up. The patients were divided into five quintile groups, and the relationship between PaCO2 and all-cause death in sepsis patients was studied using restricted cubic splines (RCSs). Results: Our study included 4898 sepsis patients, the hypocapnia (PaCO2 &lt; 31 mmHg) and hypercapnia (PaCO2 ≥ 49 mmHg) groups were associated with the risk of death in sepsis patients using quintile grouping and the multivariate Cox model, with HRs of 1.12 (95% CI = 1.03–1.29) and 1.25 (95% CI = 1.10–1.41), respectively, when compared with the control group (37 ≤ PaCO2 &lt; 41 mmHg). The relationship between PaCO2 and all-cause death in sepsis patients was U-shaped. Conclusion: The presence of hypercapnia and hypocapnia at the time of hospital admission will have adverse effects on all-cause death in sepsis patients.

PULM7: Toward Automatic Control Of Arterial Blood Paco2 Using Artificial Lung Exhaust Gas CO2 As A Surrogate

Purpose: Current clinical Extra Corporeal CO2 removal systems rely on human intervention to adjust to changes in patient activity. Previous studies have investigated the use of capnography for measurement of arterial blood carbon dioxide tension (PaCO2) using artificial lungs (AL). The presented work demonstrates an initial implementation of a controller that directly monitors and regulates PaCO2 using exhaust gas CO2 (EGCO2) measurements. Method: The system operates through two cycles, namely measurement and control. First, the sweep gas flow through the AL is temporarily (~60s) reduced to ~400 mL/min to allow the CO2 concentration on the blood and gas phase of the AL to equilibrate. This allows for EGCO2 (measured via a CO2Meter GC-0017) values to be used as an estimate of PaCO2. The control cycle is based on Proportional-Integral-Derivative (PID) principle wherein the system automatically modulates sweep gas flows through the AL to minimize the difference between the desired PaCO2 and the estimated PaCO2 (i.e., measured EGCO2). Blood samples were intermittently collected at the inlet of the AL to monitor actual PaCO2 (measured via a Radiometer ABL800 Flex blood gas analyzer). The in vitro study setup (Fig. 1) consists of a Novalung iLA oxygenator (main AL) and a Capiox RX25 oxygenator (conditioning AL) connected in parallel to model a typical ECMO circuit. The blood reservoir mimics the blood volume (7 L) while the centrifugal pump simulates cardiac output (fixed at ~5 L/min) of a patient. Blood flow through the main AL (AV shunt) was regulated at ~1 L/min using a Hoffman clamp. CO2 concentration in the sweep gas through the conditioning AL was modulated to simulate metabolic activity. The baseline CO2 concentration measured at the outlet of the conditioning AL that projects reservoir PaCO2 level when the main AL is not operational. The baseline blood concentration was varied between 45 and 90 mmHg representing all levels of normocapnia and hypercapnia. Results: Prior to the controller testing, a feasibility study was performed to determine the accuracy of capnography technique in calculating the PaCO2 using the AL. A total of forty-two blood samples were collected at blood flow rates of 0.5, 0.6 and 1.0 L/min. The results show a good correlation between PaCO2 and EGCO2 (r2=0.824, P<0.001). There was a reasonable degree of agreement between the PaCO2 and EGCO2 with accuracy (bias or mean difference between PaCO2 and EGCO2) of 6.04 mmHg with a precision (95% limits of agreement) of ± 9.62 mmHg (Fig. 2). Despite the limitation of the AL in estimating PaCO2 using EGCO2, the PID controller implementation demonstrated that average reservoir CO2 concentration can be maintained at 44.23 ± 8.7 mmHg for a target PaCO2 of 40 mmHg (Fig. 3),against baseline blood reservoir PaCO2 of 60.76 ± 13.81 mmHg.Figure 1. Image showing in vitro test setup. The bovine blood in the test circuit was anticoagulated (ACT > 1200s) with heparin and maintained at 37°C.Figure 2. a) The regression curve generated between PaCO2 samples and measured EGCO2 b) Agreement between PaCO2 samples and measured EGCO2.Figure 3. a) In vitro test results showing changes in all PaCO2 concentrations in the circuit b) Result summary comparing average reservoir PaCO2 level with target PaCO2

1040 Sleep Hypoventilation with Daytime Eucapnia in COPD May Predict Hypercapnia During Exacerbation

Abstract Introduction Patients with severe Chronic Obstructive Pulmonary Disease (COPD) are known to be at risk for nocturnal hypoventilation1. We present a case of patient with severe COPD with near normalization of PaCO2 levels after exacerbation but persistent nocturnal hypoventilation. Report of case(s) 71-year-old woman with COPD Group 4D, on home oxygen, was seen in pulmonary clinic after two hospitalizations for hypercapnic respiratory failure, PcO2 &amp;gt;100 mm Hg requiring acute Noninvasive ventilation (NIV) support. Three weeks after discharge, ABG improved to 7.39/49/140 on 32% Fio2, preventing her from qualifying for long-term home NIV. Sleep study was negative for sleep apnea but showed hypoventilation during sleep. Wake supine transcutaneous CO2 was 45-47 mmHg, increasing to 51-55 mmHg during sleep, worse with supplemental oxygen to 66-67 mm. Conclusion Chronic hypercapnia is a poor prognostic indicator in COPD4. In patients with persistent hypercapnia following COPD exacerbation, NIV prolongs time to re-admission or death within 12 months2. Blunting of chemoreceptor response has been noted in hypercapnic patients3, possibly causing subsequent daytime hypercapnia and overt respiratory failure. However, nocturnal hypercapnia is present in some patients and may be a risk factor for profound, life-threatening hypercapnia during exacerbation. Future studies are needed to better phenotype patients such as ours who may be seemingly eucapnic in between exacerbations, but markedly hypercapnic during exacerbation, to determine if there is benefit in treating these patients with NIV as well. Support (if any) 1. The American Academy of Sleep Medicine Task Force. Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. Report of American Academy of Sleep Medicine Task Force. Sleep 1999:22:667-689 2. Murphy PB, Rehal S, Arbane G, Bourke S, Calverley PMA, Crook AM, et al. Effect of home noninvasive ventilation with oxygen therapy vs oxygen therapy alone on hospital readmission or death after an acute COPD exacerbation: a randomized clinical trial. JAMA. 2017:317:2177 3. Scano G,Spinelli A, Duranti R, et al. Carbon dioxide responsiveness in COPD patients with and without chronic hypercapnia. Eur Respir J 1995:8:78-85 4. Cooper CB, Waterhouse J, Howard P. Twelve-year clinical study of patients with hypoxic co pulmonale given long term domiciliary oxygen therapy. Thorax 1987:42:105-110