Arterial Oxygen Pressure Research Articles

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.

Normoxic Management during Cardiopulmonary Bypass Does Not Reduce Cerebral Mitochondrial Dysfunction in Neonatal Swine.

Optimal oxygen management during pediatric cardiopulmonary bypass (CPB) is unknown. We previously demonstrated an increase in cortical mitochondrial reactive oxygen species and decreased mitochondrial function after CPB using hyperoxic oxygen management. This study investigates whether controlled oxygenation (normoxia) during CPB reduces cortical mitochondrial dysfunction and oxidative injury. Ten neonatal swine underwent three hours of continuous CPB at 34 °C (flow > 100 mL/kg/min) via cervical cannulation targeting a partial pressure of arterial oxygen (PaO2) goal < 150 mmHg (normoxia, n = 5) or >300 mmHg (hyperoxia, n = 5). The animals underwent continuous hemodynamic monitoring and serial arterial blood sampling. Cortical microdialysate was serially sampled to quantify the glycerol concentration (represents neuronal injury) and lactate-to-pyruvate ratio (represents bioenergetic dysfunction). The cortical tissue was analyzed via high-resolution respirometry to quantify mitochondrial oxygen consumption and reactive oxygen species generation, and cortical oxidized protein carbonyl concentrations were quantified to assess for oxidative damage. Serum PaO2 was higher in hyperoxia animals throughout CPB (p < 0.001). There were no differences in cortical glycerol concentration between groups (p > 0.2). The cortical lactate-to-pyruvate ratio was modestly elevated in hyperoxia animals (p < 0.03) but the values were not clinically significant (<30). There were no differences in cortical mitochondrial respiration (p = 0.48), protein carbonyls (p = 0.74), or reactive oxygen species generation (p = 0.93) between groups. Controlled oxygenation during CPB does not significantly affect cortical mitochondrial function or oxidative injury in the acute setting. Further evaluation of the short and long-term effects of oxygen level titration during pediatric CPB on cortical tissue and other at-risk brain regions are needed, especially in the presence of cyanosis.

Effect of dexmedetomidine on pulmonary function in obese patients undergoing laparoscopic surgery

ObjectiveThis research aimed to ascertain the effect of dexmedetomidine on pulmonary function in obese patients undergoing laparoscopic surgery.MethodsObese patients undergoing laparoscopic surgery under general anesthesia were separated into the control group (group C) and the dexmedetomidine group (group D) (n = 30). Patients in group D were infused with dexmedetomidine (1 μg/kg) intravenously for 10 min and then at a rate of 0.5 mg/kg h until 30 min before the end of the surgery, and those in group C were infused with an equal volume of saline. The surgery time points were divided into: before anesthesia induction (T0), 5 min after intubation (T1), 30 min after pneumoperitoneum (T2), 10 min after pneumoperitoneum release (T3), at the time of extubation (T4), 3 min after extubation (T5), and 24 h after surgery (T6). Arterial blood was collected for blood gas analysis to record arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2). Dynamic lung compliance (Cdyn), oxygenation index (OI), alveolar-arterial oxygen partial pressure difference (A-aDO2), and respiratory index (RI) were calculated. The time of surgery, anesthesia, CO2 pneumoperitoneum, eye-opening, and time from the end of surgery to extubation were recorded. Plasma IL-8 and IL-10 levels were measured from T0 to T6.ResultsThe time of surgery, anesthesia, CO2 pneumoperitoneum, eye-opening, and time from the end of surgery to extubation in group D were not statistically significant when compared with those in group C. Versus at the T1 time point, A-aDO2 and RI were higher and Cdyn and OI were lower in both groups at T2 and T3 time points. Versus group C, group D had higher Cdyn and OI and lower A-aDO2 and RI at T2 and T3 time points. Versus at the T0 time point, at each time point from T1 to T6, IL-8 and IL-10 levels were higher in both groups. Versus group C, group D had lower IL-8 and higher IL-10 levels at each time point from T1 to T6.ConclusionIn obese patients undergoing laparoscopic surgery under general anesthesia, the use of dexmedetomidine can improve the lung compliance and OI of the patients, inhibit the inflammatory response of the lungs of the patients and thus have a certain protective effect on the lung function.

Clinical characteristics of non-sleepy obstructive sleep apnea patients: a study in a tertiary care sleep clinic in India.

Obstructive sleep apnea (OSA) encompasses a diverse population, manifesting with or without symptoms of excessive daytime sleepiness. There is contention surrounding the significance of non-sleepy OSA within clinical contexts and whether routine treatment is warranted. This study aims to evaluate epidemiological and clinical distinctions between sleepy and non-sleepy OSA patients. A retrospective analysis was conducted on consecutive patients undergoing polysomnography for OSA assessment at tertiary care hospitals between 2018 and 2023. For 176 of 250 patients, complete polysomnography records with OSA diagnoses were available. Non-sleepy OSA was defined when a patient had an Epworth sleepiness scale score <10 and polysomnography demonstrated an apnea hypopnea index ≥5/hour. Non-sleepy OSA patients were matched with sleepy OSA patients in terms of age and gender distribution (mean age 51.24±13.25 years versus 50.9±10.87 years, male 70.4% versus 73.3%). The sensitivity of STOP-BANG≥3 for the non-sleepy OSA group was 87.7%, 89.3%, and 95.2% for any OSA severity, moderate to severe OSA, and severe OSA, respectively, while the corresponding sensitivity for the sleepy OSA group was 96.5%, 98.6%, and 100% for any OSA severity, moderate to severe OSA, and severe OSA, respectively. A novel symptom scoring tool, HASSUN (hypertension, nocturnal apneas, snoring, sleep disturbance, unrefreshing sleep, and nocturia), demonstrated a sensitivity of over 90% for all severity categories of OSA in both non-sleepy and sleepy OSA groups. The prevalence of cardiovascular and metabolic comorbidities did not significantly differ between non-sleepy and sleepy OSA patients. The physiological parameters, including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC ratio, arterial partial pressure of oxygen, and bicarbonate at baseline, were comparable between the two groups. To conclude, non-sleepy OSA patients are less obese, exhibit fewer symptoms, and have less severe OSA in comparison to sleepy OSA. Non-sleepy OSA patients display a similar likelihood of cardiovascular and metabolic comorbidities compared to sleepy OSA patients. Further investigations are warranted to elucidate the mechanisms underlying cardiovascular metabolic comorbidities in non-sleepy OSA patients. The proposed HASSUN scoring tool for non-sleepy OSA screening necessitates validation in future studies.

Oxygen targets following immediate percutaneous coronary intervention in comatose survivors of out-of-hospital cardiac arrest - a BOX sub-study

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Novo Nordisk Foundation The Lundbeck Foundation. Background Treatment with supplemental oxygen in patients with acute myocardial infarction (AMI) has previously been associated with poorer outcomes. However, in patients with AMI resuscitated from out-of-hospital cardiac arrest (OHCA) and undergoing immediate revascularization, evidence regarding specific oxygen targets is sparse. Purpose To assess the impact of a restrictive versus a liberal oxygen target on infarct size in OHCA patients undergoing immediate percutaneous coronary intervention (PCI). Methods The current study is a sub-study of the BOX trial, a randomized trial with a 2-by-2 factorial design, in which comatose OHCA patients with a presumed cardiac cause of arrest were randomly assigned to either a restrictive oxygen target (partial pressure of arterial oxygen (Pao2) of 9 to 10 kPa) or a liberal oxygen target (Pao2 of 13 to 14 kPa). In this sub-study we included patients who underwent immediate revascularization with PCI. The primary outcome was myocardial infarct size as assessed by the cardiac enzyme troponin-T (TnT). TnT was measured repeatedly during the first 72 hours and analyzed with a repeated measures variance component model with baseline adjustment. Secondary outcome was one-year all-cause mortality assessed by Kaplan-Meier and Cox proportional hazards analyses. Results A total of 329 patients underwent immediate PCI, whereof 172 patients were randomized to the restrictive oxygen target and 157 to the liberal oxygen target. The oxygen intervention was successful with a significantly higher PaO2 in the liberal oxygen target group during the first 72 hours (p&amp;lt;0.0001). Baseline characteristics and findings on coronary angiography (CAG) were similar in the two oxygen target groups. Thus, median age was 63 (interquartile range (IQR) 55–71), 81% were male, and estimated left ventricular ejection fraction on arrival to hospital was 35% (IQR 25–45%). Further, 74% of the patients had an initial postresuscitation electrocardiogram with ST-segment elevations, and the left anterior descending artery was deemed as culprit lesion in 49% of the patients. There was no difference in peak TnT between the restrictive and liberal oxygen target group (median 2540 (IQR 925–6420) versus 3410 (792–8630), ng/l, p=0.23), nor did TnT differ between the groups during the first 72 hours after admission (Figure 1, p=1.00). Within one year from admission, 120 patients (36.5%) had died. There was no difference in mortality between the restrictive (34%) and liberal (39%) oxygen target group (hazard ratio, 0.80; 95% CI, 0.56-1.14; p=0.21) (Figure 2). Conclusion Targeting a restrictive versus a liberal oxygen level in comatose survivors of OHCA who underwent immediate revascularization did not affect infarct size nor did it result in a significant difference in one-year mortality rate.Figure 1:Troponin-T levelsFigure 2:Kaplan-Meier curves

Oxygen delivery and consumption in comatose out-of-hospital cardiac arrest patients are affected by blood pressure targets

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Grosserer L. F. Foghts Fond Background Hemodynamic instability is common after resuscitated out-of-hospital cardiac arrest (OHCA). Preventing inadequate oxygen delivery (DO2) to the cells and thus not meeting oxygen demand is crucial to prevent further organ dysfunction. Additionally, oxygen uptake in the cells may be impaired. Oxygen consumption (VO2; the amount of oxygen consumed by the body per minute) could thus also be affected in OHCA. Purpose This study aimed to describe the effect of different mean arterial blood pressure (MAP) and partial arterial oxygen pressure (PaO2) targets on DO2 and VO2. Methods This post-hoc study is based on the BOX trial, a 2x2 factorial design that randomized OHCA patients to a MAP of either 63 mmHg (MAP63) or 77 mmHg (MAP77) and a partial pressure of arterial oxygen of 9 to 10 kPa or a liberal oxygen target of a PaO2 of 13 to 14 kPa at two cardiac centers in Denmark. Pulmonary artery catheters were placed to evaluate cardiac output and collect mixed venous blood samples at prespecified time points. Oxygen blood contents were calculated for arterial (CaO2) and mixed venous blood (CvO2) as Hgb (mg/dl) x 10 x 1.39 x Saturation O2 (proportion) + 0.0225 x PaO2. DO2 = CO x CaO2, and VO2 = CO x (CaO2-CvO2). Results This study included 715 patients (90% of the total cohort with a pulmonary catheter) for analysis. A restrictive or liberal oxygen supplement did not affect DO2 or VO2 during the initial 48 hours. The MAP77 group exhibited on average 11% higher DO2 (95%CI: 6%-15%) and on average a 6% higher VO2 in the first 48 hours (95%CI: 3%-10%) compared to the MAP63 group (see Figure 1). Conclusion Targeting a PaO2 of either 9 to 10 kPa or 13 to 15 kPa resulted in no significant changes in the provision of oxygen to the cells, nor did it increase the consumption of oxygen. In contrast, targeting a MAP of 77 mmHg resulted in an increase in both the provision of oxygen and consumption of oxygen compared to a MAP target of 63 mmHg.Figure 1

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.

Association between arterial oxygen and mortality across critically ill patients with hematologic malignancies: results from an international collaborative network.

Patients with hematological malignancies are at high risk for life-threatening complications. To date, little attention has been paid to the impact of hyperoxemia and excess oxygen use on mortality. The aim of this study was to investigate the association between partial pressure of arterial oxygen (PaO2) and 28-day mortality in critically ill patients with hematologic malignancies. Data from three international cohorts (Europe, Canada, Oceania) of patients who received respiratory support (noninvasive ventilation, high-flow nasal cannula, invasive mechanical ventilation) were obtained. We used mixed-effect Cox models to investigate the association between day one PaO2 or excess oxygen use (inspired fraction of oxygen ≥ 0.6 with PaO2 > 100mmHg) on day-28 mortality. 11,249 patients were included. On day one, 5716 patients (50.8%) had normoxemia (60 ≤ PaO2 ≤ 100mmHg), 1454 (12.9%) hypoxemia (PaO2 < 60mmHg), and 4079 patients (36.3%) hyperoxemia (PaO2 > 100mmHg). Excess oxygen was used in 2201 patients (20%). Crude day-28 mortality rate was 40.6%. There was a significant association between PaO2 and day-28 mortality with a U-shaped relationship (p < 0.001). Higher PaO2 levels (> 100mmHg) were associated with day-28 mortality with a dose-effect relationship. Subgroup analyses showed an association between hyperoxemia and mortality in patients admitted with neurological disorders; however, the opposite relationship was seen across those admitted with sepsis and neutropenia. Excess oxygen use was also associated with subsequent day-28 mortality (adjusted hazard ratio (aHR) [95% confidence interval (CI)]: 1.11[1.04-1.19]). This result persisted after propensity score analysis (matched HR associated with excess oxygen:1.31 [1.20-1.1.44]). In critically-ill patients with hematological malignancies, exposure to hyperoxemia and excess oxygen use were associated with increased mortality, with variable magnitude across subgroups. This might be a modifiable factor to improve mortality.

Comparative effects of variable versus conventional volume-controlled one-lung ventilation on gas exchange and respiratory system mechanics in thoracic surgery patients: A randomized controlled clinical trial

BackgroundMechanical ventilation with variable tidal volumes (V-VCV) has the potential to improve lung function during general anesthesia. We tested the hypothesis that V-VCV compared to conventional volume-controlled ventilation (C-VCV) would improve intraoperative arterial oxygenation and respiratory system mechanics in patients undergoing thoracic surgery under one-lung ventilation (OLV). MethodsPatients were randomized to V-VCV (n = 39) or C-VCV (n = 39). During OLV tidal volume of 5 mL/kg predicted body weight (PBW) was used. Both groups were ventilated with a positive end-expiratory pressure (PEEP) of 5 cm H2O, inspiration to expiration ratio (I:E) of 1:1 (during OLV) and 1:2 during two-lung ventilation, the respiratory rate (RR) titrated to arterial pH, inspiratory peak-pressure ≤ 40 cm H2O and an inspiratory oxygen fraction of 1.0. ResultsSeventy-five out of 78 Patients completed the trial and were analyzed (dropouts were excluded). The partial pressure of arterial oxygen (PaO2) 20 min after the start of OLV did not differ among groups (V-VCV: 25.8 ± 14.6 kPa vs C-VCV: 27.2 ± 15.3 kPa; mean difference [95% CI]: 1.3 [−8.2, 5.5], P = 0.700). Furthermore, intraoperative gas exchange, intraoperative adverse events, need for rescue maneuvers due to desaturation and hypercapnia, incidence of postoperative pulmonary and extra-pulmonary complications, and hospital free days at day 30 after surgery did not differ between groups. ConclusionsIn thoracic surgery patients under OLV, V-VCV did not improve oxygenation or respiratory system mechanics compared to C-VCV.Ethical Committee: EK 420092019.Trial registration: at the German Clinical Trials Register: DRKS00022202 (16.06.2020).

High-flow nasal oxygen in resource-constrained, non-intensive, high-care wards for COVID-19 acute hypoxaemic respiratory failure: Comparing outcomes of the first v. third waves at a tertiary centre in South Africa.

High-flow nasal oxygen (HFNO) is an accepted treatment for severe COVID-19-related acute hypoxaemic respiratory failure (AHRF). To determine whether treatment outcomes at Groote Schuur Hospital, Cape Town, South Africa, during the third COVID-19 wave would be affected by increased institutional experience and capacity for HNFO and more restrictive admission criteria for respiratory high-care wards and intensive care units. We included consecutive patients with COVID-19-related AHRF treated with HFNO during the first and third COVID-19 waves. The primary endpoint was comparison of HFNO failure (composite of the need for intubation or death while on HFNO) between waves. A total of 744 patients were included: 343 in the first COVID-19 wave and 401 in the third. Patients treated with HFNO in the first wave were older (median (interquartile range) age 53 (46 - 61) years v. 47 (40 - 56) years; p<0.001), and had higher prevalences of diabetes (46.9% v. 36.9%; p=0.006), hypertension (51.0% v. 35.2%; p<0.001), obesity (33.5% v. 26.2%; p=0.029) and HIV infection (12.5% v. 5.5%; p<0.001). The partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2 /FiO2 ) ratio at HFNO initiation and the ratio of oxygen saturation/FiO2 to respiratory rate within 6 hours (ROX-6 score) after HFNO commencement were lower in the first wave compared with the third (median 57.9 (47.3 - 74.3) mmHg v. 64.3 (51.2 - 79.0) mmHg; p=0.005 and 3.19 (2.37 - 3.77) v. 3.43 (2.93 - 4.00); p<0.001, respectively). The likelihood of HFNO failure (57.1% v. 59.6%; p=0.498) and mortality (46.9% v. 52.1%; p=0.159) did not differ significantly between the first and third waves. Despite differences in patient characteristics, circulating viral variant and institutional experience with HFNO, treatment outcomes were very similar in the first and third COVID-19 waves. We conclude that once AHRF is established in COVID-19 pneumonia, the comorbidity profile and HFNO provider experience do not appear to affect outcome. What the study adds. This study adds to the body of evidence demonstrating the utility of high-flow nasal oxygen (HFNO) in avoiding invasive mechanical ventilation (IMV) in patients with severe COVID-19 hypoxaemic respiratory failure, and shows that this utility remained consistent across different waves of the COVID-19 pandemic.Implications of the study. In resource-constrained settings, HFNO is a feasible non-invasive alternative to IMV and can be employed with favourable and consistent outcomes outside traditional critical care wards. It also confirms that the degree of gas exchange abnormality, and not pre-existing patient-related factors, circulating wave variant or provider experience, is the main predictor of HFNO failure.

High velocity nasal insufflation versus non-invasive ventilation in acute respiratory failure: a comparative study

Background In order to treat respiratory failure, thermo-humidified nasal high flow oxygen (NHFO) therapy is being used more and more. In several clinical scenarios, NHFO has recently gained popularity as alternative noninvasive respiratory ventilation. Aim The aim is to assess the role of high velocity nasal insufflation (HVNI) versus noninvasive ventilation (NIV) in acute respiratory failure. Patients and methods This is a prospective randomized clinical study conducted on 60 patients admitted to the Chest Department at Menoufia University Hospital with acute respiratory failure. Patients were randomized to receive either noninvasive positive pressure ventilation using an oronasal mask or high-velocity nasal insufflation (initial flow was at 30-40 l/min; temperature was adjusted to 37°C; fraction of inspired oxygen 1.0) with clinical monitoring and arterial blood gas (ABG) monitoring after 2, 6, 12, and 24 h. Results The therapeutic impact of both, HVNI and NIV, on pressure of arterial carbon dioxide (PaCO2), hydrogen ion concentration, arterial oxygen saturation and pressure of arterial oxygen (PaO2) over time was almost similar. There was an improvement in dyspnea and a decrease in respiratory rate over time when compared with baseline results in both groups. There was no statistical difference between both groups. The failure rate in type I respiratory failure (RF) was 33.3% in the HVNI group and 28.6% in the NIV group (P-value 0.7). The failure rate in type II RF was 41.7% in the HVNI group and 25% in the NIV group (P-value 0.3). HVNI was more comfortable for patients and provided better communication and oral intake. Conclusion This study demonstrates that the HVNI was comparable to the NIV in the management of hypoxemic respiratory failure and could be used as a noninvasive method of ventilation alternative to the BiPAP in hypercapnic RF, with more comfortability and better communication in the HVNI group.

Effects of Butorphanol on Respiration in White Rhinoceros (Ceratotherium simum) Immobilized with Etorphine-Azaperone.

This article reports on respiratory function in white rhinoceros (Ceratotherium simum) immobilized with etorphine-azaperone and the changes induced by butorphanol administration as part of a multifaceted crossover study that also investigated the effects of etorphine or etorphine-butorphanol treatments. Six male white rhinoceros underwent two immobilizations by using 1) etorphine-azaperone and 2) etorphine-azaperone-butorphanol. Starting 10 min after recumbency, arterial blood gases, limb muscle tremors, expired minute ventilation, and respiratory rate were evaluated at 5-min intervals for 25 min. Alveolar to arterial oxygen gradient, expected respiratory minute volume, oxygen consumption, and carbon dioxide production were calculated. Etorphine-azaperone administration resulted in hypoxemia and hypercapnia, with increases in alveolar to arterial oxygen gradient, oxygen consumption, and carbon dioxide production, and a decrease in expired minute ventilation. Muscle tremors were also observed. Intravenous butorphanol administration in etorphine-azaperone-immobilized white rhinoceros resulted in less hypoxemia and hypercapnia; a decrease in oxygen consumption, carbon dioxide production, and expired minute ventilation; and no change in the alveolar to arterial oxygen gradient and rate of breathing. We show that the immobilization of white rhinoceros with etorphine-azaperone results in hypoxemia and hypercapnia and that the subsequent intravenous administration of butorphanol improves both arterial blood oxygen and carbon dioxide partial pressures.

Effect of Different Extubation Strategies on Atelectasis in Older Adults after Major Abdominal Surgeries: A Prospective Randomised Controlled Trial.

Older patients are particularly vulnerable to age-related respiratory changes. This prospective randomized controlled trial studied the effects of high and low fractions of inspired oxygen (FiO2) with the recruitment maneuver (RM) during extubation on lung atelectasis post-operatively in older patients undergoing major abdominal surgery. We randomized a total of 132 patients aged >60 years who underwent both elective and emergency major abdominal surgeries and met the inclusion criteria into three groups (H, HR, and LR) using computer-generated block randomization. Group H received high FiO2 (1), Group HR received high FiO2 (1) with RM followed by a positive end-expiratory pressure of 5 cm H2O, and Group LR received low FiO2 (0.4) with RM followed by a positive end-expiratory pressure of 5 cm H2O 10 min before extubation. Oxygenation and atelectasis were measured using the arterial partial pressure of oxygen (PaO2)/FiO2 ratios and lung ultrasound score. Postoperative pulmonary complications were recorded up to 24 h postoperatively. The mean PaO2/FiO2 at 30 min post-extubation was significantly higher in Groups LR and HR compared to that in Group H (390.71 ± 29.55, 381.97 ± 24.97, and 355.37 ± 31.7, p <0.001). In the immediate postoperative period, the median lung ultrasound score was higher in Group H than that in Groups LR and HR (6 [5-7]), 3 [3-5], and 3.5 [2.25-4.75], p <0.001). The incidence of oxygen desaturation and oxygen requirements was higher in Group H during the postoperative period. The RM before extubation is beneficial in reducing atelectasis and postoperative pulmonary complications, irrespective of the FiO2 concentration used in older adults undergoing major abdominal surgeries.

Identification of the essential and critical factors of decision-making for COVID-19 patient management: a mixed-method study

Background: Understanding the contributing factors for decision-making based on the disease stage is highly crucial to improving patient care. Aim: This study aimed to identify the critical and essential factors to enhance clinical decision-making for COVID-19 patients. Methods: This mixed-method research was conducted in two phases. In the first phase, a systematic literature review was performed using defined search strategies across four databases, including PubMed, Scopus, Web of Science, and IEEE. A total of 136 studies were obtained. Next, a questionnaire-based survey was conducted to validate the findings from the review and to categorize the factors into essential and critical factors. The content validity ratio was used to categorize the factors accordingly. The identified factors were classified into six main categories based on the stages of care and the corresponding decision-making. Results: The expert panel consisted of 10 clinicians from various fields. The potential factors were categorized into six categories. A total of 293 factors were found in the literature review. The findings of the consensus survey revealed 10 factors related to the decisions on the length of stay, eight factors for ward referral decisions, one factor for decisions on home referrals, six factors for deterioration diagnosis decisions, two factors for discharge decisions, and 10 factors for decisions on intensive care unit referrals. In addition, the study identified respiratory rate, oxygen saturation at administration, arterial oxygen pressure, sequential organ failure assessment score, and glomerular filtration rate as significant decision-making factors for COVID-19 patient management. Conclusion: For medical emergencies (e.g., COVID-19 management), fewer but more significant factors may increase the efficiency of decision-making, thereby improving the quality of patient management. On this basis, this study identified the essential and critical factors for decision-making at different stages of COVID-19 patient management. Relevance for Patients: This study identified the most important factors in diagnosing the deterioration of COVID-19 patients to improve the treatment outcome of COVID-19 patients.

Comparison of SpO2- with PaO2-Based Indices of Oxygenation in Children with Respiratory Failure

AbstractGiven the widespread availability of pulse oximetry and its potential to replace partial pressure of arterial oxygen (PaO2)-based indices of oxygenation, we aimed to study the correlation between pulse oximetry-based oxygen saturation (SpO2)- and PaO2-based indices of oxygenation namely, SpO2/FiO2 (SF) ratio with PaO2/FiO2 (PF) ratio and oxygen saturation index (OSI) with oxygenation index (OI) under varying physiological conditions, along with accuracy measures for SpO2-based indices. Inclusion criteria included children (1 month to 18 years) admitted to pediatric intensive care unit needing invasive ventilation for hypoxemic respiratory failure with SpO2 ≥ 80% and having an indwelling arterial catheter. A total of 1,237 sets of simultaneous PaO2, SpO2 readings, and ventilator parameters were recorded. There was a moderate correlation between SF and PF ratios (r s = 0.68, p &lt; 0.001) and strong correlation between OSI and OI (r s = 0.89, p &lt; 0.001). We obtained SF ratios of 271, 235, and 200 corresponding to PF ratios of 300, 200, and 100, respectively. SF ratio showed a good discrimination ability to identify moderate (area under the receiver operating characteristic curve [AUROC] = 0.901) and severe acute respiratory distress syndrome (ARDS; AUROC = 0.889) and fair discrimination ability for mild ARDS (AUROC = 0.770). OSI of 4.1, 6.4, and 11.1 corresponded to OI of 4, 8, and 16, respectively. OSI demonstrated an excellent discrimination ability for diagnosing mild (AUROC = 0.928), moderate (AUROC = 0.961), and severe ARDS (AUROC = 0.965). The correlation between SF/PF ratio and OSI/OI was the strongest in the lowest SpO2 range studied. SpO2-based indices of oxygenation could replace PaO2-based indices with reasonable accuracy for patients with SpO2 values ≥ 80%.

Effects of tidal volume on physiology and clinical outcomes in patients with one‑lung ventilation undergoing surgery: A meta‑analysis of randomized controlled trials.

There is no detailed study on how tidal volume (VT) affects patients during one-lung ventilation (OLV). The present study conducted a meta-analysis to assess the effect of VT on physiology and clinical outcomes in OLV patients. Databases until February 2023 were retrieved from PubMed, Cochrane Library and Web of Science. Randomized controlled trials comparing the application of low and high VT ventilation in adults with OLV were performed. Demographic variables, VT, physiology, and clinical outcomes were retrieved. The random-effects model calculated the summary of odds ratios with 95% confidence intervals (CI) and mean difference with standard deviation. A total of 12 studies involving a total of 876 participants met the inclusion criteria. Low VT ventilation was associated with decreased risk of acute lung injury [relative risk 0.50, 95% CI (0.28, 0.88), P=0.02]. Low VT ventilation decreased the driving pressure (ΔP) and peak pressure (Ppeak) and improved arterial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2). Furthermore, the present study suggested that a significant difference in blood IL-6 was observed between low and high VT ventilation [mean difference, -35.51 pg/ml, 95% CI (-66.47, -4.54 pg/ml), P=0.02]. A decrease in the length of stay at the hospital occurred in the low VT group when set to 4-5 ml/kg. In the OLV patients, low VT ventilation decreased the risk of acute lung injury, blood IL-6, ΔP and Ppeak, and improved PaO2/FiO2. Furthermore, when low VT was set to 4-5 ml/kg, the length of stay at the hospital decreased.

Prone position in the mechanical ventilation of acute respiratory distress syndrome children: a systematic review and meta-analysis.

Prone position has been well recognized for the treatment of adult acute respiratory distress syndrome (ARDS). We aimed to evaluate the role of prone position in the mechanical ventilation in children with ARDS, to provide evidence to the treatment and care of children with ARDS. We searched the Pubmed et al. databases by computer until January 23, 2024 for randomized controlled trials (RCTs) on the role of prone position in the mechanical ventilation in children with ARDS. We evaluated the quality of included studies according to the quality evaluation criteria recommended by the Cochrane library. RevMan 5.3 software was used for meta-analysis. 7 RCTs involving 433 children with ARDS were included. Meta-analysis indicated that prone position is beneficial to improve the arterial oxygenation pressure [MD = 4.27 mmHg, 95% CI (3.49, 5.06)], PaO2/FiO2 [MD = 26.97, 95% CI (19.17, 34.77)], reduced the oxygenation index [MD = -3.52, 95% CI (-5.41, -1.64)], mean airway pressure [MD = -1.91 cmH2O, 95% CI (-2.27, -1.55)] and mortality [OR = 0.33, 95% CI (0.15, 0.73), all P < 0.05]. There were no statistical differences in the duration of mechanical ventilation between the prone position group and control group [MD = -17.01, 97.27, 95% CI (-38.28, 4.26), P = 0.12]. Egger test results showed that no significant publication bias was found (all P > 0.05). Prone position ventilation has obvious advantages in improving oxygenation, but there is no significant improvement in the time of mechanical ventilation in the treatment of children with ARDS. In the future, more large-sample, high-quality RCTs are still needed to further analyze the role of prone position in the mechanical ventilation in children with ARDS.

Effects of therapeutic hypercapnia on the expression and function of γδT cells in transplanted lungs in rats.

To investigate the effect of therapeutic hypercapnia on the expression and function of gamma delta T (γδ T) cells during ischemia-reperfusion injury (IRI) after lung transplantation. We randomly divided male Wistar rats into three groups (n = 6 in each group), the control group (group N), the IRI group (group I), and the therapeutic hypercapnia group (group H). We then assessed pulmonary edema, neutrophil infiltration, wet-to-dry (W/D) weight ratio, and microscopic histopathology and separately measured the levels of γδT cell surface antigen (TCR) and Interleukin-17 (IL-17) using flow cytometry and enzyme-linked immunosorbent assays (ELISAs). The infiltration of neutrophils and the expression of TCR and IL-17 were significantly increased in the I group compared to the control, and the biopsy edema in group I was more severe. Arterial partial pressure of oxygen (PaO2) was decreased after reperfusion in group I compared with the control group. W/D weight ratio, neutrophil infiltration, and the expression of TCR and IL-17 decreased drastically in the H group compared to the I group. Our findings suggest that γδ T lymphocytes were directly involved in lung injury. In addition, therapeutic hypercapnia effectively reduced the expression of γδ T cells and IL-17, and this has the potential to become a treatment strategy for IRI and an intervention to improve lung function.

Dexmedetomidine improves lung injury after one-lung ventilation in esophageal cancer patients by inhibiting inflammatory response and oxidative stress.

To explore the effect of Dexmedetomidine (DEX) on lung injury in patients undergoing One-lung ventilation (OLV). Esophageal cancer patients undergoing general anesthesia with OLV were randomly divided into the DEX group and control group, with 30 cases in each group. Mean arterial pressure (MAP), heart rate (HR), arterial partial pressure of oxygen (PO2), and arterial partial pressure of nitrogen dioxide (PCO2) were recorded at the time points after anesthesia induction and before OLV (T1), OLV 30 min (T2), OLV 60 min (T3), OLV 120 min (T4), OLV end before (T5) and before leaving the room (T6) in both groups. Reverse Transcription-Polymerase Chain Reaction (RT-qPCR) was applied to detect the levels of CC16 mRNA. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum CC16 protein levels. The content of malondialdehyde (MDA) in serum was determined by thio barbituric acid (TBA) method. ELISA was used to measure the concentrations of TNF-α (tumor necrosis factor-alpha)/and IL-6 (interleukin 6). DEX treatment slowed down HR at time points T1-T6 and increased PO2 and PCO2 at time points T2-T5 compared with the control group. Moreover, at time points T2-T6, DEX treatment reduced the levels of club cell secretory protein-16 (CC16) mRNA and serum CC16 protein levels. Furthermore, DEX treatment caused the reduction of MDA, TNF-α and IL-6 concentrations in serum of patients. During the OLV process, DEX could reduce serum CC16 protein levels, inhibit inflammatory reactions and oxidative stress, and improve oxygenation index, indicating a protective effect on lung injury during OLV.

Application of high flow nasal canula in patients with pulmonary edema caused by seawater drowning

To investigate the therapeutic effect of high-flow nasal cannula oxygen therapy (HFNC) and non-invasive positive pressure ventilation (NPPV) on patients with pulmonary edema caused by seawater drowning. A retrospective analysis method was used. Based on the Utstein database of emergency drowning in the First Hospital of Qinhuangdao, the clinical data of patients with seawater drowning pulmonary edema admitted to the emergency medicine department of the First Hospital of Qinhuangdao from January 1, 2019 to December 31, 2022 were collected. The patients were divided into NPPV group and HFNC group according to different ventilation methods. The general data, endotracheal intubation rate in 7 days, arterial blood gas analysis indexes [arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), arterial oxygen saturation (SaO2)] and hemodynamic indexes (systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, blood lactic acid) before and after treatment, length of stay in intensive care unit (ICU), oxygen therapy comfort of the two groups were compared. A total of 54 patients were enrolled, including 21 patients in the NPPV group and 33 patients in the HFNC group. There were no significant differences in gender, age, state of consciousness and other general information between the two groups. Compared with NPPV group, the rate of endotracheal intubation in HFNC group within 7 days was significantly lower [24.2% (8/33) vs. 33.3% (7/21), P < 0.05]. Before treatment, there were no significant differences in arterial blood gas analysis and hemodynamics between the two groups. After treatment, the above indexes in both groups were significantly improved compared with those before treatment, and PaO2, SaO2, systolic blood pressure, diastolic blood pressure and mean arterial pressure in HFNC group were significantly higher than those in NPPV group [PaO2 (mmHg, 1 mmHg≈0.133kPa): 93.56±6.37 vs. 82.14±6.25, SaO2: 1.02±0.09 vs. 0.95±0.11, systolic blood pressure (mmHg): 117.37±8.43 vs. 110.42±8.38, diastolic blood pressure (mmHg): 79.43±7.61 vs. 72.21±4.32, mean arterial pressure (mmHg): 92.34±6.32 vs. 85.12±5.38], PaCO2, heart rate and blood lactic acid were significantly lower than those in NPPV group [PaCO2 (mmHg) : 34.26±5.63 vs. 37.24±6.22, heart rate (times/min): 73.38±7.56 vs. 86.25±5.41, blood lactic acid (mmol/L): 1.38±0.36 vs. 2.25±1.14], and the differences were statistically significant (all P < 0.05). In addition, the length of ICU stay in HFNC group was significantly shorter than that in NPPV group (days: 13.30±2.38 vs. 16.27±4.26), and the comfort rate of oxygen therapy was significantly higher than that in NPPV group [66.7% (22/33) vs. 42.8% (9/21)], with statistical significance (all P < 0.05). HFNC can improve the oxygenation of patients with pulmonary edema caused by seawater drowning, improve hemodynamics, reduce the rate of tracheal intubation, shorten the length of ICU stay, and improve the comfort of oxygen therapy, which has certain clinical application value.