PaO2 Values Research Articles

Peripheral oxygen saturation levels as a guide to avoid hyperoxia: an observational study

BackgroundAs iatrogenic hyperoxia has been related to adverse outcomes in critically ill patients, guidelines advise to titrate oxygen to physiological levels. In the prehospital setting where partial arterial oxygen (PaO2) values are often not readily available, titration of oxygen is based on peripheral oxygen saturations (SpO2). In this study we aimed to investigate the efficacy of SpO2 guided oxygen titration in the prevention of hyperoxia.MethodsIn a retrospective observational cohort study of patients included in the Acutelines data- and biobank of the University Medical Center Groningen between September 2020 and March 2023, we collected blood gas samples and triage data of sequentially included patients who received oxygen at the moment they were presented in the emergency department (ED). PaO2 values were compared to (concurrently measured) SpO2 values, and to patient- and treatment characteristics and P/F ratios were calculated in order to investigate the efficacy of SpO2 based oxygen titration for various subgroups.ResultsBlood gas samples were obtained for 1042 patients, of which 178 (17.1%) had hyperoxia (PaO2 levels > 13.5 kPa). SpO2 readings were available for 170 of these, 68 of which (40%) had SpO2 values above the recommended target range (94–98%; 88–92% for patients with COPD) whereas 102 patients (60%) had SpO2 values within- or even below the recommended target range. Many of these patients (44.1%) received oxygen through a low-flow device (nasal canula), and these patients almost invariably (84.4%) were not compromised in their ventilation (P/F ratio’s > 300).ConclusionWhen oxygen is titrated based on SpO2 levels, this results in hyperoxemia in a significant proportion of the patients. Health care providers should especially be reluctant to administer (low flow) oxygen as a standard of care to patients who do not have clear respiratory compromise, as these patients are at a high risk of developing (occult) hyperoxia.

Predictive performance of ROX index and its variations for NIV failure.

To determine whether the ROX index and its variations can predict the risk of intubation in ICU patients receiving NIV ventilation using large public ICU databases. Retrospective observational cohort study. Patient data was extracted from both the AmsterdamUMCdb and the MIMIC-IV ICU databases, which contained data related to 20,109 and 50,920 unique patients. Non-invasively mechanically ventilated. Retrospective review of variables. To assess the predictive values of models for each index, the ROX and its variations mROX, ROX-HR and mROX-HR were calculated based on mean values of SpO2, respiratory rate, FiO2 and PaO2 from 2-h windows within the first 12 h of NIV. 3344 patients were eligible for analysis of which 1344 were intubated, died or returned to NIV within 24 h of ending NIV. NIV failure group had higher SOFA scores and higher CRP levels at admission. There was no difference in duration of NIV therapy or 28-day mortality, but patients who failed NIV had longer length of stay. The best performing index was ROX with an AUROC of 0.626 at 10-12 h. All other indices for all other time windows were less discriminating. The performance of ROX index and its variations to predict NIV failure in ICU patients across large public ICU databases was moderate at best and cannot currently be recommended for clinical decision support.

Association Between Arterial Hyperoxia and Mortality in Pediatric and Adult Patients Undergoing Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis.

In patients receiving extracorporeal membrane oxygenation (ECMO) support, the association between arterial hyperoxia and outcomes is unclear. We performed a systematic review and meta-analysis to determine the association between arterial Po2 (Pao2) and mortality in patients with ECMO. The meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement and registered in International Prospective Register of Systematic Reviews (PROSPERO; CRD42023467361). We systematically searched PubMed and Embase databases up to September 2023 for randomized trials or observational studies that investigated the association between Pao2 and mortality in pediatric and adult patients receiving venovenous ECMO (VV-ECMO), venoarterial ECMO (VA-ECMO), and extracorporeal cardiopulmonary resuscitation (ECPR). The predefined outcome was 28-day mortality. We synthesized the data using a random-effects model, calculating odds ratios (OR) and corresponding 95% confidence intervals (CI). Thirteen cohort studies (17,766 participants) were included. All studies used categorical Pao2 cutoff, with varying thresholds ranging from ≥100 mm Hg to ≥300 mm Hg. When compared with patients with normoxia, elevated Pao2 levels at all studied thresholds were consistently associated with increased mortality (≥300 mm Hg: OR 1.56, 95% CI, 1.31-1.85, P < .01; ≥200 mm Hg: OR 1.43, 95% CI, 1.10-1.87, P < .01; ≥150 mm Hg: OR 1.51, 95% CI, 1.15-1.98, P < .01; and ≥100 mm Hg: OR 1.44, 95% CI, 1.03-2.02, P = .03). A sensitivity analysis focusing on studies reporting adjusted OR yielded similar results. We observed this association in both adult and pediatric populations. In critically ill patients on VV- or VA-ECMO, increased Pao2 values were associated with increased 28-day mortality in ECMO patients. Our results should be interpreted with caution given observational nature of included studies. Further randomized trials are warranted to validate these results.

Evolution of the oxyhemoglobin dissociation curve in COVID-19 related ARDS patients.

Severe hypoxemia is the leading cause of admission in intensive care (ICU) in patients with COVID-19 related acute respiratory distress syndrome (ARDS). In these patients, several studies reported a left shift of the oxyhemoglobin dissociation curve associated with a lower mortality. However, these results are conflicting, as these studies include few patients and often no control groups. Moreover, the calculation of P50, representing the PaO2 value at which 50% of hemoglobin is saturated, is not corrected for factors known to influence it (pH, PaCO2 or temperature). For all of these reasons, we compared the corrected P50 between ICU patients with severe COVID-19 related ARDS on mechanical ventilation or not, and ARDS from other causes. We investigated the evolution of the corrected P50 during the first 3 days of ICU and its relationship with ICU mortality. We retrospectively calculated the corrected P50 in three groups of patients: intubated and mechanically ventilated COVID-19 related ARDS, non-intubated COVID-19 related ARDS and intubated patients with ARDS due to other infectious causes. The corrected P50 was calculated, on the worst blood gas analysis on days 1 and 3 of ICU admission, by the formula of Hill but modified by Dash et al., controlled for pH, PaCO2 and temperature. We collected ICU mortality. 463 blood gas analysis at days 1 and 3 from 214 ICU COVID-19 related ARDS patients (114 with intubation and 100 without) and 35 ICU patients with ARDS from other causes were analyzed. All patients were severely hypoxemic: PaO2/FiO2 of 76 [58-108] mmHg for intubated COVID-19, 79 [60-108] mmHg for non-intubated COVID-19 and 142 [78-197] mmHg for the third group (p < 0.001). The mortality rate was higher in intubated COVID-19 related ARDS patients (44.7 versus 14 versus 37% in ARDS from other causes; p < 0.001). The corrected P50 was significantly lower in COVID-19 patients, especially in non- intubated patients (21.2 [18.8-25.2] mmHg vs. 25.5 [19.2-30.3] mmHg in intubated patients; compared to ARDS from other causes: 27.2 [23.3-35.4] mmHg; p < 0.001. The corrected P50 does not change over the first 3 days, except for the non intubated COVID-19 related ARDS and is not correlated with ICU mortality (odds ratio = 0.98 [0.95-1.03]; p = 0.51), in contrast of PaO2/FiO2 and ICU gravity scores. The oxyhemoglobin dissociation curve at ICU admission was left shifting in severe COVID-19 related ARDS patients regardless of the type of ventilation. This deviation increases the third day only in non-intubated COVID-19 related ARDS and was not related to the outcome.

Association between arterial oxygen tension with clinical outcomes in patients undergoing VA-ECMO support: a systematic review and dose-response meta-analysis

Abstract Background Arterial hyperoxia has been associated with a worse prognosis in critically ill patients. However, studies conducted in patients undergoing Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) used inconsistent and arbitrary thresholds for defining hyperoxia, which impeded the determination of the optimal target for arterial oxygen tension (PaO2) in this population. Purpose To investigate and visualise the dose-response relationship between post-ECMO level of PaO2 with early mortality (in-hospital and 1-month) and poor neurological outcomes in adult patients undergoing VA-ECMO support, including Extracorporeal Cardiopulmonary Resuscitation (ECPR). Methods A systematic search was conducted through Pubmed and Embase to include studies that stratified patients based on PaO2 levels and evaluated relevant outcomes. We utilised either adjusted Odds Ratio (OR) with 95% Confidence Interval (CI) when available, or unadjusted OR against the lowest exposure category. The median, mean, or midpoint value of PaO2 was assigned as the corresponding dose. A random-effects one-stage dose-response meta-analysis was performed to assess linear association for every 10 mmHg increase in PaO2, while potential non-linear relationship was explored with restricted cubic splines at 3 knots (10th, 50th, and 90th percentile). Non-linearity was assessed by using Wald test with p value &amp;lt;0.05 considered significant. Statistical analyses were performed using STATA 17.0. Results Fourteen eligible records were identified (cardiogenic shock/CS = 5 records; ECPR = 8 records; both = 1 record). Only four studies classified a separate category for hypoxemic patients (&amp;lt;60 mmHg). PaO2 levels were measured within 24-72 hours of VA-ECMO initiation, except in one study. PaO2 level was not associated with early mortality (9 studies; OR 1.021 [95% CI 0.988–1.055]; p for non-linearity = 0.893), but found to have a linear association with composite poor neurological outcomes (6 studies; OR 1.016 [1.009–1.024]; p for non-linearity = 0.346). Subgroup analysis of CS patients revealed a linear association between PaO2 &amp;gt;100 mmHg and early mortality (4 studies; OR 1.025 [95%CI 1.018–1.032]; p for non-linearity = 0.255). For ECPR patients, a J-shaped relationship was observed between PaO2 and early mortality (5 studies; p for non-linearity = 0.004), with the lowest odds being at PaO2 level of 110-210 mmHg, while PaO2 level &amp;gt;110 mmHg showed a linear trend towards higher odds of poor neurological function (4 studies; OR 1.091 [95%CI 0.938–1.269]; p for non-linearity = 0.257). Conclusion Pooled data from observational studies suggest that PaO2 &amp;gt;100 mmHg should be avoided in CS patients on VA-ECMO support, given its linear association with mortality, but it cannot be extrapolated to hypoxemic patients. In ECPR patients, PaO2 level around 110-210 mmHg conferred the best clinical outcomes. However, these findings should be confirmed through randomised controlled trials.

Case-control study on risk factors for in-hospital mortality in patients with severe COVID-19.

The purpose of this study was to identify independent risk factors affecting patient survival and explore predictors of severe cases of coronavirus disease 2019 (COVID-19). We conducted a retrospective, observational, case-control study on adult patients with severe COVID-19 who were admitted to affiliated hospitals in Tianjin between December 18, 2022, and January 31, 2023. We used univariate and multifactorial logistic regression analyses to analyze demographic indicators, comorbidity profiles, and laboratory parameters in two groups of patients (deceased and surviving) to identify independent risk factors for death in patients with severe COVID-19. Patients in the deceased group were older than those in the survival group (p = 0.018), and there were more cases of coexisting respiratory insufficiency in the deceased group (p = 0.002). Additionally, laboratory test results for white blood cell count (WBC) and creatine kinase (CK) showed significantly higher values in the deceased group (p = 0.047 and p = 0.029, respectively), while arterial oxygen partial pressure (PAO2) showed significantly lower values compared to the survival group (p = 0.021). Age, respiratory insufficiency, WBCH (highest WBC value), CKH (highest CK value), and PAO2F (first PAO2 value) had area under curve (AUC) values of 0.698, 0.838, 0.721, 0.744, and 0.633, respectively. The main risk factors for mortality in patients with severe COVID-19 that we identified in this study were the advanced age of patients, coexisting respiratory insufficiency, elevated levels of WBC and CK, and decreased levels of PAO2. Elevated WBC and CK laboratory parameters, in particular, demonstrated good predictive value for in-hospital mortality risk.

Assessing the incidence of hyperoxia and the effectiveness of Oxygen Reserve Index-guided FiO2 titration in hyperoxia prevention

BackgroundAlthough pulse oximetry technology, which is considered the standard of care to ensure optimum oxygenation, is indispensable in clinical practice, especially in the detection of hypoxemia, it has some limitations in the detection of hyperoxemia. Oxygen Reserve Index can provide clinicians with a crucial pathway in detecting and preventing hyperoxia, noninvasively. Our aim in this study is to determine the hyperoxia detection ability of ORi and to investigate the effectiveness of ORi and SpO2-guided FiO2 titration in preventing hyperoxia.MethodsThis prospective randomized study was conducted in the operating theater of Health Sciences University İzmir Tepecik Training and Research Hospital from September 1, 2020, to December 1, 2022. Patients undergoing major abdominal surgery were divided into two groups: the control group and the SpO2 + ORi group. FiO2 titration was performed in the SpO2 + ORi group to maintain the ORi between 0.00 and 95% < SpO2 ≤ 98%. Parameters were recorded before induction, 10 min after intubation, and every hour during the operation.ResultsA positive linear relationship of 75.8% (r = 0.758) was found between PaO2 and ORi in the ORi + SpO2 group (p < 0.001). Moderate hyperoxemia was observed in 31.6% of patients in the control group, while it was not observed in the ORi + SpO2 group at the 3rd hour. PaO2 values decreased significantly over time in the ORi + SpO2 group with FiO2 titration (p < 0.001).ConclusionThe combined use of SpO2 and ORi has been demonstrated to successfully guide FiO2 titration for optimal oxygenation and reduce hyperoxemia.

Correlation between invasive and noninvasive oxygen indices in critically ill COVID patients with ARDS: A retrospective analysis

Objective: This study aims to evaluate the correlation between peripheral oxygen saturation/fraction of inspired oxygen (SpO2/FiO2) and arterial partial pressure of oxygen (PaO2)/FiO2 ratio in the diagnosis and assessment of severity in acute respiratory distress syndrome (ARDS) patients admitted to intensive care unit (ICU) during the SARS-CoV-2 outbreak. Methods: A retrospective observational study was conducted in patients admitted to COVID-ICU during a 1-year period. Time coinciding values of SpO2 and PaO2 were noted from patients’ medical records. An evaluation was made to judge the efficacy of the SpO2/FiO2 ratio (S/F ratio) for the prediction of 100, 200, 300, and &gt;300 mmHg cutoff values of PaO2/FiO2 ratio (P/F ratio) using receiver operating characteristic (ROC) curves. Results: The medical records of 196 patients were evaluated. A strong positive correlation was identified between P/F and S/F ratios in the sample population (correlation coefficient r = 0.716, p &lt; 0.002). The area under the ROC curve of the S/F ratio was 0.720 (95% confidence interval [CI] 0.637–0.804) for mild ARDS. The optimal S/F threshold was found to be ≤411% (sensitivity and specificity 65% and 80%, respectively). Similarly, the S/F threshold was ≤405% (area under the curve [AUC] 0.781, 95% CI 0.713–0.848, p &lt; 0.000) for moderate ARDS (sensitivity 71.8% and specificity 70.8%), and ≤ 395% (AUC 0.762, 95% CI 0.689–0.835, p &lt; 0.000) for severe ARDS (specificity 73.5% and sensitivity 66.7%). Conclusions: The S/F ratio can be used as a reliable, noninvasive alternative tool for the diagnosis of ARDS and assessment of severity. This can be used as an early warning score in patients admitted in low-resource settings with respiratory illness, and an escalation of care can be decided.

The Impact of Traditional Chinese Herbal Decoctions Combined with Rehabilitation Therapy on Pulmonary Function and Respiratory Muscle Strength in COVID-19 Recovery Patients.

This study aims to evaluate the clinical efficacy of integrated traditional Chinese and Western medicine rehabilitation treatment during the recovery period of COVID-19, providing a scientific basis for developing more effective rehabilitation protocols. The study included 120 COVID-19 (novel coronavirus) recovery patients treated at our hospital from November 2021 to April 2022. After registration, patients were randomly divided into two groups, namely the study group and the control group. The control group received conventional rehabilitation treatment, while the study group underwent integrated traditional Chinese and Western medicine rehabilitation treatment, with 60 cases in each group. The clinical observation indicators in this study include the results of the 6-minute walk test (6MWT), respiratory and circulatory parameters, pulmonary function, changes in respiratory muscle strength, and quality of life in both groups of patients. The 6MWT distance increased significantly in both groups, with the study group showing a larger improvement (P < 0.05). SpO2 and PaO2 values improved significantly in both groups, with greater increases in the study group (P < 0.05). Lung function parameters (FEV1 and FEV1/FVC) improved significantly in the study group compared to the control group (P < 0.05). Diaphragmatic thickness and mobility were also significantly higher in the study group (P < 0.05). The SF-36 quality of life scores were significantly better in the study group (P < 0.05). Integrated traditional Chinese and Western medicine rehabilitation treatment has achieved significant efficacy during the recovery period of COVID-19. The complementary use of traditional Chinese medicine's differential diagnosis and treatment and modern medical approaches from Western medicine provides patients with comprehensive and personalized rehabilitation services, offering new ideas and methods to improve the quality of patient recovery.

Pulmonary Events in ICU patients with hyperoxia: is it possible to relate arterial partial pressure of oxygen to coded diseases? A retrospective analysis

ObjectiveOxygen has been used liberally in ICUs for a long time to prevent hypoxia in ICU- patients. Current evidence suggests that paO2 >300 mmHg should be avoided, it remains uncertain whether an “optimal level” exists. We investigated how “mild” hyperoxia influences diseases and in-hospital mortality. DesignThis is a retrospective study. Setting112 mechanically ventilated ICU-patients were enrolled. Patients or participants112 ventilated patients were included and categorized into two groups based on the median paO2 values measured in initial 24 h of mechanical ventilation: normoxia group (paO2 ≤ 100 mmHg, n = 43) and hyperoxia group patients (paO2 > 100 mmHg, n = 69). InterventionsNo interventions were performed. Main variables of interestThe primary outcome was the incidence of pulmonary events, the secondary outcomes included the incidence of other new organ dysfunctions and in-hospital mortality. ResultsThe baseline characteristics, such as age, body mass index, lactate levels, and severity of disease scores, were similar in both groups. There were no statistically significant differences in the incidence of pulmonary events, infections, and new organ dysfunctions between the groups. 27 out of 69 patients (39.1%) in the “mild” hyperoxia group and 12 out of 43 patients (27.9%) in the normoxia group died during their ICU or hospital stay (p = 0.54). The mean APACHE Score was 29.4 (SD 7.9) in the normoxia group and 30.0 (SD 6.7) in the hyperoxia group (p = 0.62). ConclusionsWe found no differences in pulmonary events, other coded diseases, and in-hospital mortality between both groups. It remains still unclear what the "best oxygen regime" is for intensive care patients.

Predictive Hypoxemic Threshold for Tolerating the Apnea Test While Assessing Death by Neurological Criteria

Abstract Background The apnea test (AT) plays a vital role in diagnosing brain death by evaluating the absence of spontaneous respiratory activity. It entails disconnecting the patient from mechanical ventilation to raise the CO2 partial pressure and lower the pH. Occasionally, the AT is aborted because of safety concerns, such as hypoxemia and hemodynamic instability, to prevent worsening conditions. However, the exact oxygen partial pressure level needed before commencing AT, indicating an inability to tolerate the test, is still uncertain. This study seeks to determine pre-AT oxygen levels linked with a heightened risk of test failure. Methods We conducted a retrospective cohort study involving patients suspected of having brain death at the Tel Aviv Medical Center from 2010 to 2022. The primary outcome was defined as an arterial partial O2 pressure (PaO2) level of 60 mmHg or lower at the conclusion of the AT. This threshold is significant because it marks the point at which the saturation curve deflects, potentially leading to rapid deterioration in the patient’s oxygen saturation. Results Among the 70 patients who underwent AT, 7 patients met the primary diagnostic criteria. Patients with a PaO2 ≤ 60 mmHg at the conclusion of the AT exhibited a significantly lower initial median PaO2 of 243.7 mmHg compared with those with higher pre-AT PaO2 levels of 374.8 mmHg (interquartile range 104.65–307.00 and interquartile range 267.8–444.9 respectively, P value = 0.0041). Pre-AT PaO2 levels demonstrated good discriminatory ability for low PaO2 levels according to the receiver operating characteristic (ROC) curve, with an area under the curve of 0.76 (95% confidence interval 0.52–0.99). Conclusions PaO2 values at the conclusion of the AT are closely associated with PaO2 values at the beginning of the test. Establishing a cutoff value of approximately 300 mmHg PaO2 at the onset of AT may assist in avoiding saturation drops below 90%.

Repercussions of SARS-CoV-2 infection on intrapulmonary shunt in patients undergoing one-lung ventilation

BackgroundHypoxic pulmonary vasoconstriction is the most important regulatory mechanism by which right-to-left shunts decrease during one-lung ventilation (OLV), but the effects of pulmonary microarterial thrombosis and impaired HPV after SARS-CoV-2 infection on intrapulmonary shunt during OLV remain unknown. The aim of this study was to observe the changes of intrapulmonary shunt in patients undergoing thoracoscopic partial pneumonectomy at different periods after SARS-CoV-2 infection compared with patients without SARS-CoV-2 infection history.MethodsA total of 80 patients who underwent elective thoracoscopic partial lung resection and were classified as American Society of Anaesthesiologists (ASA) grades I-II were selected and divided into 4 groups (n = 20 in each group): patients not infected with SARS-CoV-2 (Group A), patients infected with SARS-CoV-2 for 5–8 weeks (Group B), patients infected with SARS-CoV-2 for 9–12 weeks (Group C), and patients infected with SARS-CoV-2 for 13–16 weeks (Group D). For all patients, the same anaesthesia method was adopted, and anaesthesia was maintained with propofol, remifentanil, and cisatracurium. Radial artery and mixed venous blood gases were measured at 10 min of two-lung ventilation (TLV), 15 min of one-lung ventilation (OLV15), and 30 min of OLV (OLV30) in the lateral recumbent position to calculate the intrapulmonary shunt. Multiple linear regression analysis was employed to investigate the association between intrapulmonary shunt and SARS-CoV-2 infection.ResultsQs/Qt at TLV was significantly higher in Groups B and C than in Group A (P < 0.05), and PaO2 at TLV was significantly lower in Groups B and C than in Group A (P < 0.05). Qs/Qt values at OLV15 and OLV30 were significantly higher in Group B, C or D than in Group A (P < 0.05), and PaO2 values at OLV15 and OLV30 were significantly lower in Groups B, C or D than in Group A (P < 0.05). Multiple linear regression analysis revealed that SARS-CoV-2 infection (95%CI -4.245 to -0.679, P = 0.007) was an independent risk factor for increased intrapulmonary shunt during TLV, while SARS-CoV-2 infection (95%CI 0.124 to 3.661, P = 0.036), exacerbation of COVID-19 clinical classification (95%CI -5.203 to -1.139, P = 0.003), and persistent symptoms (95%CI -12.122 to -5.522, P < 0.001) were independent risk factors for increased intrapulmonary shunt during OLV after SARS-CoV-2 infection.ConclusionSARS-CoV-2 infection increased intrapulmonary shunt and reduced oxygenation. Although oxygenation improved at TLV after 13–16 weeks of infection, intrapulmonary shunt and oxygenation under OLV took longer to recover.Trial registrationChinese Clinical Trial Registry, Retrospectively registered, Full date of first registration: 17/05/2023, Registration number: ChiCTR2300071539.

The Comparative Impact of Liberal Versus Conservative Oxygenation in Critically Ill COVID-19 Patients: A Retrospective Study.

Objectives Whether a higher or lower partial pressure of oxygen (PaO2) could impact outcomes in patients with coronavirus disease 2019 (COVID-19) remains a matter of debate. So, we planned this retrospective analysis to determine if a higher or lower partial pressure of oxygen in blood had any effect on outcomes in COVID-19 patients. Material and method The records of COVID-19 patients from the beginning of 2020 to the end of 2022 were scanned. Patients were sub-grouped into two groups based on the partial pressure of oxygen (PaO2) values on arterial blood gas (ABG), i.e., high PaO2group,PaO2 value of 80-100 mm Hg, and low PaO2group,PaO2 value of 60-80 mm Hg for the first 48 hours after the initiation of oxygenation and/or mechanical ventilation. The two groups were compared in terms of partial pressure of oxygen in arterial blood to the fraction of inspiratory oxygen (FiO2) concentration (P/F ratio), Sequential Organ Failure Assessment (SOFA) score at presentation and after 48 hours, and clinical outcomes, including mortality, time of mortality, extubation, acute kidney injury (AKI), and change in Glasgow Coma Scale (GCS). Results SOFA score was significantly higher in the low PaO2 group as compared to the high PaO2 group both at baseline (4.59 {1.79} versus 5.51 {1.15}; p-value: 0.005) and at 48 hours (3.06 {1.39} versus 5.11 {2.13}; p-value: 0.007). However, the change in SOFA score over 48 hours did not achieve statistical significance (-1.000 {0.97} versus 0.53 {2.34}; p-value: 0.257). Out of a total of 37 patients, 21 patients died in the high PaO2 group, while 18 patients died in the low PaO2 group. Conclusion Our study highlights that targeting either low or high arterial oxygen content while considering oxygen therapy for COVID-19 patients did not significantly alter the outcomes.

Evaluation of feasibility and safety of non-intubated anesthesia video-assisted thoracoscopic thymectomy for myasthenia gravis

Video-assisted thoracoscopic surgery (VATS) thymectomy is a well-established treatment for Myasthenia gravis (MG). However, traditional VATS thymectomy uses general anesthesia with endotracheal intubation, which can worsen MG symptoms. This study evaluated the feasibility and safety of non-intubated anesthesia VATS for patients with MG to solve this issue. It was a prospective, descriptive study involving six patients aged 18 to 60, ASA I, II, who underwent VATS thymectomy under non-intubated anesthesia and local anesthesia at Vietduc University Hospital between May 2022 and December 2023. The induction time was short, ranging from 3 to 4.5 minutes. The median of Peak PaCO2 and EtCO2 were 42.5 mmHg (range 33-49 mmHg) and 46.4 mmHg (range 44-48 mmHg), respectively. The median values of PaO2 and SpO2 during one-lung ventilation were 161.1 mmHg (range 82-206.9 mmHg) and 98% (range 93-99%). The lungs collapsed well, and breathing and circulation remained stable. No complicationarose, and all patients recovered well. These initial findings suggest that non-intubated anesthesia is a safe and straightforward option for MG thymectomy

The value of N-acetylcysteine bronchoalveolar lavage in patients with severe traumatic brain injury combined with ventilator-associated pneumonia

In order to improve the treatment of patients with ventilator-associated pneumonia (VAP) in severe traumatic brain injury (TBI) and to effectively suppress the inflammatory response and enhance blood oxygen indicators, we conducted an innovative bronchoalveolar lavage (BAL) treatment using N-acetylcysteine (NAC). To conduct this study, we divided patients with VAP in severe TBI into a control (CTRL) group and a BAL group. The control group received BAL with saline, while the BAL group received BAL with NAC in addition to standard care. We compared the clinical treatment, degree of inflammation, blood oxygen index, and safety of both groups pre- and post-BAL. The results showed that BAL with NAC was more effective in reducing the duration of antibiotic use, imaging uptake, fever reduction, mechanical ventilation, and ICU stay, as well as CPIS and APACHE II scores. Moreover, the BAL group demonstrated greater improvement in ventilation, as indicated by increased values of PaO2, SaO2, and OI, and a more substantial decrease in PaCO2. Furthermore, BAL treatment effectively suppressed the level of inflammatory response in the body and more significantly reduced TNF-α, CPR, PCT and MIP-1α levels. Adjuvant treatment with BAL effectively improved clinical outcomes and reduced mortality in severe TBI patients with VAP, while maintaining a high level of safety during the BAL operation. Therefore, BAL using NAC holds significant potential in the salvage of patients with severe TBI combined with VAP.

Association Between Early Hyperoxemia Exposure and Intensive Care Unit Mortality in Intracerebral Hemorrhage: An Observational Cohort Analysis.

Supraphysiologic levels of oxygen could have potential adverse effects on the brain that may be dose and time dependent in patients with brain injury. We therefore aimed to assess whether exposure to excess supplemental oxygen, measured as time-weighted mean exposure to hyperoxemia, was associated with intensive care unit (ICU) mortality in patients with intracerebral hemorrhage (ICH). In this single-center retrospective cohort study, we included all patients admitted to our ICU with a diagnosis of primary spontaneous ICH. To provide a longitudinal measure of hyperoxemia exposure, we calculated the hyperoxemia dose, defined as the area under the partial pressure of oxygen in arterial blood (PaO2) time curve above the threshold PaO2 value of 100mm Hg (13.3kPa) divided by the number of hours of potential exposure. To provide consistent potential exposure windows and limit bias from informative censoring, nested subsets were created with progressively longer exposure periods (0-1day, 0-2days, 0-3days, 0-4days, 0-5days, 0-6days, 0-7days). We used multivariable Cox regression, with hyperoxemia dose as a time-dependent covariate, to model ICU mortality. Admission ICH and Acute Physiology and Chronic Health Evaluation II scores were included as predictor covariables. A step-function extended Cox model was also fitted. Between September 2019 and July 2022, 275 patients met the inclusion criteria, with 24,588 arterial blood gas results available for analysis. The mean age was 57.19years (± 13.99), 59.64% were male, 23.64% had an infratentorial origin of hemorrhage, and ICU mortality was 35.64%. Almost all patients (97.45%) were exposed to hyperoxemia during their ICU admission. Cox regression modeling showed an association between hyperoxemia dose and ICU mortality (hazard ratio 1.15, confidence interval 1.05-1.25, p = 0.003). This association was observed in the 0-1day subset in the step-function extended Cox model (hazard ratio 1.19, confidence interval 1.06-1.35, p = 0.005) but not in any of the subsequent exposure periods. In patients with ICH admitted to the ICU, we observed an association between hyperoxemia dose and ICU mortality. Further prospective study is required to inform guidance on early systemic oxygen targets in ICH.

Hyperacute experimental model of rat lung transplantation using a coronary shunt cannula.

Lung transplantation is a well-established treatment of end-stage lung disease. A rodent model is an inexpensive way to collect biological data from a living model after lung transplantation. However, mastering the surgical technique takes time owing to the small organ size. To conduct rat lung transplantation using a shunt cannula (SC) or modified cannula (MC) and assess their efficacy. Rat lung transplantation was performed in 11 animals in the SC group and 12 in the MC group. We devised a method of rat lung transplantation using a coronary SC for coronary artery bypass surgery as an anastomosis of pulmonary arteriovenous vessels and bronchioles. The same surgeon performed all surgical procedures in the donor and recipient rats without using a magnifying glass. The success rate of lung transplantation, operating time, and PaO2 values were compared after 2-h reperfusion after transplantation. Ten and 12 lungs were successfully transplanted in the SC and MC groups, respectively. In the SC group, one animal had cardiac arrest within 1 h after reperfusion owing to bleeding during pulmonary vein anastomosis. The operating time for the removal of the heart-lung block from the donor and preparation of the left lung graft was 26.8 ± 2.3 and 25.7 ± 1.3 min in the SC and MC groups, respectively (P = 0.21). The time required for left lung transplantation in the recipients was 37.5 ± 2.8 min and 35.9 ± 1.4 min in the SC and MC groups, respectively (P = 0.12). PaO2 values at 2 h after reperfusion were 456.2 ± 25.5 and 461.2 ± 21.5 mmHg in the SC and MC groups, respectively (P = 0.63), without difference between the groups. A hyperacute rat lung transplantation model using a coronary SC was created using a simple technique. The MC was inexpensive, easy to prepare, and simple to operate.

The association of arterial partial oxygen pressure with mortality in critically ill sepsis patients: a nationwide observational cohort study

BackgroundAlthough several trials were conducted to optimize the oxygenation range in intensive care unit (ICU) patients, no studies have yet reached a universal recommendation on the optimal a partial pressure of oxygen in arterial blood (PaO2) range in patients with sepsis. Our aim was to evaluate whether a relatively high arterial oxygen tension is associated with longer survival in sepsis patients compared with conservative arterial oxygen tension.MethodsFrom the Korean Sepsis Alliance nationwide registry, patients treated with liberal PaO2 (PaO2 ≥ 80 mm Hg) were 1:1 matched with those treated with conservative PaO2 (PaO2 < 80 mm Hg) over the first three days after ICU admission according to the propensity score. The primary outcome was 28-day mortality.ResultsThe median values of PaO2 over the first three ICU days in 1211 liberal and 1211 conservative PaO2 groups were, respectively, 107.2 (92.0–134.0) and 84.4 (71.2–112.0) in day 1110.0 (93.4–132.0) and 80.0 (71.0–100.0) in day 2, and 106.0 (91.9–127.4) and 78.0 (69.0–94.5) in day 3 (all p-values < 0.001). The liberal PaO2 group showed a lower likelihood of death at day 28 (14.9%; hazard ratio [HR], 0.79; 95% confidence interval [CI] 0.65–0.96; p-value = 0.017). ICU (HR, 0.80; 95% CI 0.67–0.96; p-value = 0.019) and hospital mortalities (HR, 0.84; 95% CI 0.73–0.97; p-value = 0.020) were lower in the liberal PaO2 group. On ICU days 2 (p-value = 0.007) and 3 (p-value < 0.001), but not ICU day 1, hyperoxia was associated with better prognosis compared with conservative oxygenation., with the lowest 28-day mortality, especially at PaO2 of around 100 mm Hg.ConclusionsIn critically ill patients with sepsis, higher PaO2 (≥ 80 mm Hg) during the first three ICU days was associated with a lower 28-day mortality compared with conservative PaO2.

Pulmonary Events in ICU patients with hyperoxia: is it possible to relate arterial partial pressure of oxygen to coded diseases? A retrospective analysis

ObjectiveOxygen has been used liberally in ICUs for a long time to prevent hypoxia in ICU- patients. Current evidence suggests that paO2 >300 mmHg should be avoided, it remains uncertain whether an “optimal level” exists. We investigated how “mild” hyperoxia influences diseases and in-hospital mortality. DesignThis is a retrospective study. Setting112 mechanically ventilated ICU-patients were enrolled. Patients or participants112 ventilated patients were included and categorized into two groups based on the median paO2 values measured in initial 24 h of mechanical ventilation: normoxia group (paO2 ≤ 100 mmHg, n = 43) and hyperoxia group patients (paO2 > 100 mmHg, n = 69). InterventionsNo interventions were performed. Main variables of interestThe primary outcome was the incidence of pulmonary events, the secondary outcomes included the incidence of other new organ dysfunctions and in-hospital mortality. ResultsThe baseline characteristics, such as age, body mass index, lactate levels, and severity of disease scores, were similar in both groups. There were no statistically significant differences in the incidence of pulmonary events, infections, and new organ dysfunctions between the groups. 27 out of 69 patients (39.1%) in the “mild” hyperoxia group and 12 out of 43 patients (27.9%) in the normoxia group died during their ICU or hospital stay (p = 0.54). The mean APACHE Score was 29.4 (SD 7.9) in the normoxia group and 30.0 (SD 6.7) in the hyperoxia group (p = 0.62). ConclusionsWe found no differences in pulmonary events, other coded diseases, and in-hospital mortality between both groups. It remains still unclear what the "best oxygen regime" is for intensive care patients.

Arterial oxygen pressure during veno-venous extracorporeal membrane oxygenation may be increased by advancing the tip of the drainage cannula into the superior vena cava: a case report.

A simple and robust method for veno-venous extracorporeal membrane oxygenation (V-V ECMO) involves a drainage cannula into the inferior vena cava via the femoral vein (FV) and a reinfusion cannula into the right atrium (RA) via the internal jugular vein (IJV) (F-J configuration). However, with this method, the arterial oxygen (PaO2) is said to remain below 100mmHg.Since recently, in our ICU, to prevent drainage failure, we apply a modification from the commonly practiced F-J configuration by advancing the tip of the drainage cannula inserted via the FV into the superior vena cava (SVC) and crossing the reinfusion cannula inserted via the IJV in the RA (F(SVC)-J(RA) configuration). We experienced that this modification can be associated with unexpectedly high PaO2 values, which here we investigated in detail.Veno-arteriovenous ECMO was induced in a 65-year-old male patient who suffered from repeated cardiac arrest due to acute respiratory distress syndrome. His chest X-ray images showed white-out after lung rest setting, consistent with near-absence of self-lung ventilation. Cardiac function recovered and the system was converted to F(SVC)-J(RA) configuration, after which both PaO2 and partial pressure of pulmonary arterial oxygen values remained high above 200mmHg. Transesophageal echocardiography could not detect right-to-left shunt, and more efficient drainage of the native venous return flow compared to common F-J configuration may explain the increased PaO2.Although the F(SVC)-J(RA) configuration is a small modification of the F-J configuration, it seems to provide a revolutionary improvement in the ECMO field by combining robustness/simplicity with high PaO2 values.