PaO2 Values Research Articles

Combination of nitrous oxide and the modified inflation-deflation method for identifying the intersegmental plane in segmentectomy: A randomized controlled trial.

BackgroundDuring thoracoscopic segmentectomy, accurately and rapidly identifying the intersegmental plane (ISP) is of great importance. This study aimed to investigate the effect and safety of a nitrous oxide (N2O)/oxygen (O2) inspired mixture on the appearance time of the ISP (TISP) via the modified inflation‐deflation method.MethodsA total of 65 participants who underwent segmentectomy were randomized into three groups: 75% N2O (n = 24), 50% N2O (n = 23) or 0% N2O (n = 18). The 75% N2O group received a gas mixture of N2O/O2 (Fio2 = 0.25), the 50% N2O group received N2O/O2 (Fio2 = 0.5), and the 0% N2O group received 100% oxygen during lung expansion. The appearance time of satisfactory and ideal planes was recorded. Furthermore, arterial blood gas at breathing room air, one‐lung ventilation (OLV) before lung expansion, 5 and 15 min after lung expansion were also recorded.ResultsTISP was significantly shorter in the 75% N2O group (320.2 ± 65.9 s) compared with that of the 50% N2O group (552.4 ± 88.9 s, p < 0.001) and the 0% N2O group (968.3 ± 85.5 s, p < 0.001), while the 50% N2O group was shorter than that of the 0% N2O group (p < 0.001). Arterial oxygenation was significantly improved in the 0% N2O group only after lung expansion, before which there were no differences in mean PaO2 values among groups.ConclusionsThe use of N2O in the inspired gas mixture during lung expansion is an applicable strategy to rapidly identify the ISP via the modified inflation‐deflation method without any adverse effect on OLV related arterial oxygenation during segmentectomy.

Early effects of ventilatory rescue therapies on systemic and cerebral oxygenation in mechanically ventilated COVID-19 patients with acute respiratory distress syndrome: a prospective observational study

BackgroundIn COVID-19 patients with acute respiratory distress syndrome (ARDS), the effectiveness of ventilatory rescue strategies remains uncertain, with controversial efficacy on systemic oxygenation and no data available regarding cerebral oxygenation and hemodynamics.MethodsThis is a prospective observational study conducted at San Martino Policlinico Hospital, Genoa, Italy. We included adult COVID-19 patients who underwent at least one of the following rescue therapies: recruitment maneuvers (RMs), prone positioning (PP), inhaled nitric oxide (iNO), and extracorporeal carbon dioxide (CO2) removal (ECCO2R). Arterial blood gas values (oxygen saturation [SpO2], partial pressure of oxygen [PaO2] and of carbon dioxide [PaCO2]) and cerebral oxygenation (rSO2) were analyzed before (T0) and after (T1) the use of any of the aforementioned rescue therapies. The primary aim was to assess the early effects of different ventilatory rescue therapies on systemic and cerebral oxygenation. The secondary aim was to evaluate the correlation between systemic and cerebral oxygenation in COVID-19 patients.ResultsForty-five rescue therapies were performed in 22 patients. The median [interquartile range] age of the population was 62 [57–69] years, and 18/22 [82%] were male. After RMs, no significant changes were observed in systemic PaO2 and PaCO2 values, but cerebral oxygenation decreased significantly (52 [51–54]% vs. 49 [47–50]%, p < 0.001). After PP, a significant increase was observed in PaO2 (from 62 [56–71] to 82 [76–87] mmHg, p = 0.005) and rSO2 (from 53 [52–54]% to 60 [59–64]%, p = 0.005). The use of iNO increased PaO2 (from 65 [67–73] to 72 [67–73] mmHg, p = 0.015) and rSO2 (from 53 [51–56]% to 57 [55–59]%, p = 0.007). The use of ECCO2R decreased PaO2 (from 75 [75–79] to 64 [60–70] mmHg, p = 0.009), with reduction of rSO2 values (59 [56–65]% vs. 56 [53–62]%, p = 0.002). In the whole population, a significant relationship was found between SpO2 and rSO2 (R = 0.62, p < 0.001) and between PaO2 and rSO2 (R0 0.54, p < 0.001).ConclusionsRescue therapies exert specific pathophysiological mechanisms, resulting in different effects on systemic and cerebral oxygenation in critically ill COVID-19 patients with ARDS. Cerebral and systemic oxygenation are correlated. The choice of rescue strategy to be adopted should take into account both lung and brain needs.Registration The study protocol was approved by the ethics review board (Comitato Etico Regione Liguria, protocol n. CER Liguria: 23/2020).

Lung Recruitment, Individualized PEEP, and Prone Position Ventilation for COVID-19-Associated Severe ARDS: A Single Center Observational Study.

Background: Patients with coronavirus disease 2019 (COVID-19) may develop severe acute respiratory distress syndrome (ARDS). The aim of the study was to explore the lung recruitability, individualized positive end-expiratory pressure (PEEP), and prone position in COVID-19-associated severe ARDS.Methods: Twenty patients who met the inclusion criteria were studied retrospectively (PaO2/FiO2 68.0 ± 10.3 mmHg). The patients were ventilated under volume-controlled mode with tidal volume of 6 mL/kg predicted body weight. The lung recruitability was assessed via the improvement of PaO2, PaCO2, and static respiratory system compliance (Cstat) from low to high PEEP (5–15 cmH2O). Patients were considered recruitable if two out of three parameters improved. Subsequently, PEEP was titrated according to the best Cstat. The patients were turned to prone position for further 18–20 h.Results: For recruitability assessment, average value of PaO2 was slightly improved at PEEP 15 cmH2O (68.0 ± 10.3 vs. 69.7 ± 7.9 mmHg, baseline vs. PEEP 15 cmH2O; p = 0.31). However, both PaCO2 and Cstat worsened (PaCO2: 72.5 ± 7.1 vs. 75.1 ± 9.0 mmHg; p < 0.01. Cstat: 17.5 ± 3.5 vs. 16.6 ± 3.9 ml/cmH2O; p = 0.05). Only four patients (20%) were considered lung recruitable. Individually titrated PEEP was higher than the baseline PEEP (8.0 ± 2.1 cmH2O vs. 5 cmH2O, p < 0.001). After 18–20 h of prone positioning, investigated parameters were significantly improved compared to the baseline (PaO2: 82.4 ± 15.5 mmHg. PaCO2: 67.2 ± 6.4 mmHg. Cstat: 20.6 ± 4.4 ml/cmH2O. All p < 0.001 vs. baseline).Conclusions: Lung recruitability was very low in COVID-19-associated severe ARDS. Individually titrated PEEP and prone positioning might improve lung mechanics and blood gasses.

Sleep quality in stable chronic obstructive pulmonary disease patients in Zagazig University Hospitals, Egypt

BackgroundChronic obstructive pulmonary disease (COPD) causes changes in sleep quality with accompanied nocturnal drops in oxygen saturation leading to cardiac dysrhythmias, pulmonary hypertension, and more arousal. However, this sleep disturbance is an aspect of COPD that is still under evaluation. Therefore, this work is designed to detect sleep quality with type and frequency of sleep-related breathing disorders in stable COPD patients.ResultsThis is a cross-sectional study that included 60 stable COPD patients. Full night polysomnographies were performed to all patients with assessment of their sleep quality and presence of sleep-disordered breathing. The studied patients were classified into two groups: group I (COPD with good sleep quality) and group II (COPD with poor sleep quality). The results revealed that the more severe the COPD degree, the worse the sleep quality parameters represented by sleep latency, sleep efficiency, and arousal index with a significant statistical difference (P < 0.05). Furthermore, a highly significant statistical difference was noticed regarding time spent in REM sleep among poor sleep quality patients with different grades of severity (P = 0.003). Additionally, obstructive sleep apnea hypopnea syndrome was the most frequent sleep-disordered breathing (65%), followed by nocturnal oxygen desaturation (17%) among poor quality sleeper.ConclusionAbnormal sleep quality is more common in moderate and severe COPD patients. Obstructive sleep apnea is the most frequent sleep-related breathing disorders among COPD patients. Increased BMI%, higher Berlin scores, and lower values of PaO2 and FOSQ-10 scores are strong predictors of poor sleep quality among COPD patients.

Blood gas analysis of healthy people in Diqing Tibetan Autonomous Prefecture in Yunnan Province

To investigate the reference value of blood gas analysis and related factors in healthy adults in Diqing Tibetan Autonomous Prefecture in Yunnan Province. From August 24, 2018 to August 11, 2020, healthy people between the ages of 18 and 70 years were observed at the Physical Examination Center of People's Hospital of Diqing Tibetan Autonomous Prefecture in Yunnan province. Participant information and clinical characteristics were collected. Blood gas analyzer was used to measure PH value, arterial partial oxygen pressure (PaO2), arterial partial pressure of carbon dioxide (PaCO2), arterial oxygen saturation (SaO2), acidity (pH), actual bicarbonate (AB) and residual base (BE). The participants' basic and blood gas indicator data were analyzed, and the blood gas reference values and related factors were analyzed using chi-squared tests, Mann-Whitney-Wilcoxon Test, and Spearman's correlation analysis. A total of 1,218 eligible health examination participants were included. They had an average age of 40 [31-47] years, and males accounted for 51.0%. In terms of blood gas reference values, the average pH value was moderate, and the values of PaO2, SaO2, PaCO2, AB, and BE were low. PaO2 was basically matched with the estimated value of the domestic model formula. These indexes were found to be correlated with social demographic characteristics such as sex, age, and smoking history. The correlations between the indexes and social demographic characteristics may be helpful in the prediction of blood gas analysis results in clinical practice. For men, middle-aged and elderly people, or adults with a history of active smoking/biofuel exposure, blood gas PaO2 and PaCO2 should be monitored to facilitate the early intervention of respiratory failure. The PaO2 data basically matched the estimated values of the domestic model formula, suggesting that other regions in the Prefecture could use comprehensive epidemiological data and model methods to guide clinical work.

A Retrospective Evaluation of Combination Therapy of Methylprednisolone and Remdesivir for Severe COVID-19 Patients

Introduction: Severe and threatening complications of Corona Virus Disease-2019 (COVID-19) are caused by direct viral injury as well as excessive and aberrant host immune response induced by the virus. In this context, use of Methylprednisolone (MP) to prevent cytokine storm and Remdesivir to prevent viral replication seems prudent. Aim: To assess the clinical outcome of combination therapy of Remdesivir and MP pulse therapy in patients with severe COVID-19 in Intensive Care Unit (ICU). Materials and Methods: The retrospective study was conducted in the COVID-19 ICU, dealing exclusively with 21 severe illness severe illness cases at Safdurjung Hospital, New Delhi, India from June to July 2020. They were given MP pulse therapy (500 mg/day for three days, followed by 1 mg/kg orally once daily, tapered by 10 or 20 mg/day and finishing with 10 mg) along with intravenous Remdesivir. Pre and post-therapy examination of the patients included clinical features, inflammatory markers (Interleukin-6, ferritin and D-dimer), gas parameters like ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2) and changes in chest radiograph. Values of PaO2/ FiO2, inflammatory markers on day 1 and day 3 were expressed as mean±SD and their difference compared using student t-test. Statistical significance was defined as p&lt;0.05. Results: This treatment regimen was associated with significant improvement in PaO2/FiO2 (p&lt;0.001), significant decrease in inflammatory markers (p&lt;0.001) and reversal of radiological changes. Ten patients were discharged within two weeks of treatment while six patients were shifted to high dependency unit for further oxygen requirement. They were all successfully discharged from hospital without oxygen requirement within next two weeks. Five patients developed opportunistic infections and succumbed to death. Side-effects of therapy included hyperglycaemia in nine patients, which was managed by insulin infusion. Conclusion: Combination therapy of MP pulse and Remdesivir in patients with severe COVID-19 resulted in significant clinical improvement. Given the high efficacy, it could be one of the promising approaches to the management of patients with severe COVID-19.

Uticaj brze intubacije na arterijske krvne gasove tokom faze preoksigenacije izvršene na bolničkom odeljenju urgentne medicine

Aim: During rapid sequence intubation (RSI), the O2 reserve limits the intubation duration. The study objective was to examine the impact of RSI on arterial blood gases (ABG) during the preoxygenation phase. Methods: This open, prospective clinical study examined samples of patients who had endotracheal intubation (ETI) as RSI between March 2014 and September 2014 in our emergency department. The variations in ABG PaO2 and PaCO2 before and after preoxygenation and after intubation were examined and compared with demographic and clinical variables. Results: The study included 67 patients (46 male, 21 female) with a mean age of 69.9 years. SBP, DBP, and MABP decreased, while pulse rate and SpO2 increased. No difference was observed between PaO2 values and demographic and clinical variables; however, a statistically significant relationship was found between the difference (D) between PaO2 values measured after endotracheal tracheal intubation (ETI) and after preoxygenation and the ABG SpO2 and the SpO2 classification before preoxygenation. Conclusion: The relationship between SpO2 and its classification following ETI and increased ABG SpO2 was statistically significant. Our real-life study emphasises that deciding on intubation without desaturating patients could have positive effects on intubation success. Regardless, increasing SpO2 prior to ETI will contribute positively to the O2 reserve by the end of ETI. The DPaO2 , before and after preoxygenation, was not affected by age; gender; body mass index (BMI) and its classification; GCSS; vital signs and ABG findings gathered before preoxygenation; respiration rate (RR) during preoxygenation; preoxygenation duration; oral air passage usage or air leakage.

Preliminary experimental study on the influence of different tidal volume and frequency of normal minute ventilation on the dynamic changes of carotid blood oxygen in living goats

Objective: On the basis of preliminarily verifying the use of ultra-fast reaction polymer matrix optical fiber oxygen sensor and its measuring system to record the continuous and dynamic changes of carotid artery oxygen partial pressure (PaO2), in order to analyze and discuss the influence of lung ventilation on the continuous and dynamic changes of PaO2, we designed a whole animal experimental study in vivo. Methods: Four hybrid goats were selected, and the skin was cut and exposed directly under general anesthesia and tracheal intubation. The oxygen sensor, connected with the measuring system, was inserted directly into the left carotid artery to continuously record the dynamic changes of PaO2. With normal minute ventilation,mechanical ventilation is implemented through three tidal volumes: normal tidal volume (VT=15 ml/kg, Rf=20 bpm), half tidal volume (halved VT, doubled Rf) and double tidal volume (doubled VT, halved Rf). Each tidal volume was stable for 10~15 min respectively. We analyzed and calculated the average values of PaO2, the fluctuation magnitudes of PaO2 changes between breaths of last 180 s and the delay times of lung-carotid artery were. We analyzed the effects of different tidal volumes. Results: The heart rate and blood pressure of living goats were maintained stable during the mechanical ventilation experiment with normal ventilation volume Lung-carotid artery delay time is 1.4~1.8 s (about 3 heartbeats at this time). Under normal tidal volume of mechanical ventilation, the average value of PaO2 was (102.94±2.40, 99.38~106.16) mmHg, and the fluctuation range was (21.43±1.65, 19.21~23.59) mmHg, accounting for (20.80± 1.34, 18.65~22.22)% of the average value. Under the condition of halving tidal volume, the average value of PaO2 was maintained at (101.01±4.25, 94.09~105.66) mmHg, which was slightly decreased but not significant (P>0.05 compared with normal mechanical ventilation), but the fluctuation range of PaO2 was significantly reduced to (18.14±1.43, 16.46~20.05) mmHg, accounting for 17.5% of the average value. Under double tidal volume mechanical ventilation, although the average value of PaO2 increased slightly remained at (106.42±4.74, 101.19~114.08) mmHg (P>0.05 compared with normal mechanical ventilation and P<0.05 compared with half tidal volume mechanical ventilation), the fluctuation magnitude of PaO2 increased significantly to (26.58±1.88, 23.46~28.46)mmHg. Conclusion: Inspiration and expiration of normal lung ventilation are the initial factors for the increase and decrease of PaO2 in carotid artery. Under normal ventilation, halving tidal volume and doubling tidal volume significantly changed the fluctuation magnitude of PaO2, but the average value of PaO2 changed only slightly, while the lung-carotid delay time was similar.

Многофакторный анализ дифференциально-диагностических параметров у больных бронхиальной астмой средней тяжести с пульмогенной артериальной гипертензией и эссенциальной артериальной гипертензией

Objective: to analyze differential diagnostic parameters in patients with moderate bronchial asthma with pulmogenic arterial hypertension with essential arterial hypertension. Material and Methods: 25 patients with moderate bronchial asthma with pulmogenic arterial hypertension (the 1st group) and 25 patients with moderate bronchial asthma with essential arterial hypertension (the 2nd group) were included in the study. Both groups of patients received step therapy (berodual + inhaled glucocorticosteroids). All patients underwent complex ultrasound examination of intracardiac hemodynamics, examination of blood flow in the right ventricle excretory tract. Systemic arterial pressure was measured according to N. S. Korotkov’s method. ECG was studied (24-hour monitoring). Cold test (at -20 °C-40 °C) was performed in both groups of patients, blood gas composition and pulmonary ventilation function indices were studied. Results: As a result of research established reliable differences in the spirographic indices, blood gas composition in patients with moderate bronchial asthma with pulmogenic arterial hypertension (the 1st group), and reliable differences in partial pressure of oxygen and carbon dioxide (p &lt; 0,05). The 1st group of patients has also higher values of PaCO2 and reliably (p &lt; 0,0,5) and lower values of PaO2, SaO2 in comparison with the comparison group of patients with bronchial asthma of average severity with essential arterial hypertension (the 2nd group). Our data have shown, that in the 1st and 2nd group patients systolic-diastolic cardiac function indexes reliably (p &lt; 0,05; p &lt; 0,001) differed from those ones in healthy subjects. At the same time systolic pressure in the pulmonary artery in the 1st group patients was higher than in the 2nd group patients, and left ventricular ejection fraction was significantly different from that in healthy people and was lower in the 1st group patients than in the 2nd group. We have revealed a reliable correlation between systolic blood pressure and Sа02 (r = 0,52, p &lt; 0,05), studied after cold test, which confirmed the hypothesis of the formation of pulmogenic arterial hypertension against the background of hypoxia. More pronounced changes of FEV1, Sа02, systolic blood pressure in group 1 patients were to some extent due to significant cold hyperresponsiveness in this category of patients. Conclusions: the results of our studies have shown that the decrease of FEV1, FEV50, FEV75, PaO2, SaO2, increased systolic pressure in the pulmonary artery, signs of right heart hypertrophy, disturbances of systolic-diastolic heart function were more pronounced in moderate bronchial asthma patients with pulmogenic arterial hypertension than in moderate bronchial asthma patients with essential arterial hypertension. The proportion of patients (in %) with rhythm disturbances, especially sinus tachycardia, extrasystoles were detected significantly more frequently in group 1 patients than in group 2 patients, which was due to a more pronounced disturbance of systolic-diastolic heart function, higher systolic pressure in the pulmonary artery in persons with moderate bronchial asthma with pulmogenic arterial hypertension.

A prospective study on the effectiveness of intermittent ventilation of non-dependent lung in combating hypoxia during one lung ventilation

Introduction: One lung ventilation (OLV) is required for most of the lung surgeries and one of the common problem which we encounter during this surgical procedure is hypoxia. Our prospective study evaluates the effectiveness of a low tidal volume ventilation to the operated, non- dependent lung (NDL) in improving the oxygenation during OLV. Materials and Methods: 40 ASA I, II and III patients posted for elective open thoracotomy was studied. After standard induction of anesthesia, lung separation was achieved with left sided DLT. ABG was taken on two lung ventilation (TLV) before thoracotomy and lung separation and that value was taken as base line. After thoracotomy the dependent lung alone (OLV) was ventilated for 15 mins and ABG was repeated. Then the NDL was ventilated with another ventilator with a low tidal volume and limited airway pressure and sample ABG were taken at 5 minutes and 20 minutes of NDL ventilation. Results: ABG values of PaO2 suggested that thought the values decreased during OLV compared to base line values with TLV, PaO2 had a significant increase after instituting NDL ventilation. Conclusion: NDL ventilation with low tidal volume and limited peak pressure is an effective method to avoid hypoxia and improve oxygenation during OLV requiring lung surgeries. Keywords: One lung ventilation, Hypoxemia, Two lung ventilation.

Family nursing with the assistance of network improves clinical outcome and life quality in patients underwent coronary artery bypass grafting

Background:Family nursing with the assistance of network (FNAN) improves nurses’ practice and provides family/community-oriented nursing care. This study aimed to explore the effects of FNAN on the clinical outcome and life quality of coronary atherosclerotic heart disease (CHD) patients underwent coronary artery bypass grafting (CABG).Trial Design:This study is a randomized, placebo-controlled and double-blind trial.Methods:One-hundred and twelve patients underwent CABG were randomly divided into control group (CG, routine family nursing care) and experimental group (EG, FNAN) and the allocation ratio was 1:1. The situation of anxiety and depression were analyzed using the Hamilton Anxiety Scale (HAMA) scale and Hamilton Depression Scale (HAMD). Sleep quality was measured by using Pittsburgh Sleep Quality Index (PSQI). Lung function parameters were measured, including minute ventilation (MVV), partial pressure of oxygen (PaO2), partial pressure of arterial carbon dioxide (PaCO2), oxygen saturation measurement by pulse oximetry (SpO2), forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Life quality was measured by using Chronic Obstructive Pulmonary Disease Assessment Test (CAT).Results:After a 3-month intervention, 10 and 6 patients were lost in the CG and EG groups, respectively. The scores of HAMA, HAMD, PSQI and CAT were reduced in the EG group when compared with the CG group (P < .05). The values of MVV, PaO2, SpO2, FEV1 and FVC in the EG group was higher than those in the CG group whereas the levels of PaCO2 in the EG group was lower than those in the CG group (P < .05). PSQI score had a strong relationship with the values of MVV, PaO2, PaCO2, SpO2, FEV1, and FVC.Conclusion:FNAN improves the clinical outcome and life quality in the patients underwent CABG.

Hyperoxemia and Cerebral Vasospasm in Aneurysmal Subarachnoid Hemorrhage.

Cerebral vasospasm is a major contributor to disability and mortality after aneurysmal subarachnoid hemorrhage. Oxidation of cell-free hemoglobin plays an integral role in neuroinflammation and is a suggested source of tissue injury after aneurysm rupture. This study sought to determine whether patients with subarachnoid hemorrhage and cerebral vasospasm were more likely to have been exposed to early hyperoxemia than those without vasospasm. This single-center retrospective cohort study included adult patients presenting with aneurysmal subarachnoid hemorrhage to Vanderbilt University Medical Center between January 2007 and December 2017. Patients with an ICD-9/10 diagnosis of aneurysmal subarachnoid hemorrhage were initially identified (N = 441) and subsequently excluded if they did not have intracranial imaging, arterial PaO2 values or died within 96h post-rupture (N = 96). The final cohort was 345 subjects. The degree of hyperoxemia was defined by the highest PaO2 measured within 72h after aneurysmal rupture. The primary outcome was development of cerebral vasospasm, which included asymptomatic vasospasm and delayed cerebral ischemia (DCI). Secondary outcomes were mortality and modified Rankin Scale. Three hundred and forty five patients met inclusion criteria; 218 patients (63%) developed vasospasm. Of those that developed vasospasm, 85 were diagnosed with delayed cerebral ischemia (DCI, 39%). The average patient age of the cohort was 55 ± 13years, and 68% were female. Ninety percent presented with Fisher grade 3 or 4 hemorrhage (N = 310), while 42% presented as Hunt-Hess grade 4 or 5 (N = 146). In univariable analysis, patients exposed to higher levels of PaO2 by quintile of exposure had a higher mortality rate and were more likely to develop vasospasm in a dose-dependent fashion (P = 0.015 and P = 0.019, respectively). There were no statistically significant predictors that differentiated asymptomatic vasospasm from DCI and no significant difference in maximum PaO2 between these two groups. In multivariable analysis, early hyperoxemia was independently associated with vasospasm (OR = 1.15 per 50mmHg increase in PaO2 [1.03, 1.28]; P = 0.013), but not mortality (OR = 1.10 [0.97, 1.25]; P = 0.147) following subarachnoid hemorrhage. Hyperoxemia within 72h post-aneurysmal rupture is an independent predictor of cerebral vasospasm, but not mortality in subarachnoid hemorrhage. Hyperoxemia is a variable that can be readily controlled by adjusting the delivered FiO2 and may represent a modifiable risk factor for vasospasm.

English

BACKGROUND PaO2 / FiO2 ratio has been the main criterion in defining ALI / ARDS (Acute Lung Injury / Acute Respiratory Distress Syndrome). This study is particularly aimed at utilising SpO2 / FiO2 ratio as an alternative diagnostic criterion of ALI / ARDS. METHODS Fifty patients with ALI / ARDS were included in the study. SpO2, PaO2 values, and serum electrolytes were measured using pulse oximetry and arterial blood gas analysis along with simultaneous measurement of FiO2. RESULTS SpO2 / FiO2 and PaO2 / FiO2 ratio showed a good linear correlation. By quantifying the linear regression equation, the threshold value of SpO2 / FiO2 ratio was calculated. Evidence gathered from the study demonstrated strong association between SpO2 / FiO2 and PaO2 / FiO2 ratio and it is proposed that SpO2 / FiO2 ratio calculation should be the norm to characterise oxygen impairment in ALI / ARDS, rather than just using it as an alternative diagnostic criterion. CONCLUSIONS Threshold values of SpO2 / FiO2 ratio can be used as an alternative to PaO2 / FiO2 ratio in the early diagnosis of ALI and ARDS. KEYWORDS PaO2 / FiO2 Ratio, SpO2 / FiO2 Ratio, ABG, Pulse Oximetry, ALI, ARDS

Point-of-care blood gas analyzers have an impact on the acceptance of donor lungs for transplantation

An organ donor PaO2 above 40 kPa is generally required for lung transplantation. Point-of-care (POC) blood gas analyzers are commonly used by organ procurement organizations (OPO) but may underestimate the PaO2 at high levels. We hypothesized that changing to a more accurate blood gas analyzer would result in additional lungs transplanted. All PaO2 measurements on organ donors managed at one OPO’s recovery center were performed on an i-STAT POC analyzer prior to October 2015, and on a GEM 4000 subsequently. For 24 weeks, all blood gases were tested simultaneously on both analyzers. We compared lung outcomes of 147 donors in the year prior to this change (using the i-STAT) with 56 donors in the 24-week study period (using the GEM 4000 for lung allocation). When the PaO2 was above 40 kPa, the i-STAT PaO2 was 7.2 kPa lower on average than the GEM 4000. When the GEM PaO2 measured between 40 and 50 kPa, the corresponding i-STAT PaO2 value registered less than 40 kPa 25 out of 48 times (52%), with an average difference of 7.3 kPa (SD = 2.9). The rate of lungs transplanted using the GEM 4000 was 48% compared with 35% in the year prior using the i-STAT (p = .11), with equivalent recipient outcomes. The i-STAT analyzer underestimated the PaO2 above 40 kPa and changing to a more accurate PaO2 analyzer may increase lungs transplanted.

Impact of High-Flow Nasal Cannula on Arterial Blood Gas Parameters in the Emergency Department.

Background: High-flow nasal cannula (HFNC) oxygen is becoming an integral part of respiratory failure management. Effects of HFNC on arterial blood gas (ABG) parameters especially partial carbon dioxide (PaCO2) require further investigation to provide insight into the efficacy and safety of the treatment.Methods: Acute respiratory failure patients with sequential ABG parameters before and after initiating HFNC between June 2015 and June 2017 were analyzed in a tertiary academic center. Patients' baseline characteristics were evaluated and sequential ABG changes were compared and subgrouped as chronic obstructive pulmonary disease (COPD), respiratory acidosis, hypercapnia, and high lactate.Results: A total of 120 patients were enrolled in the study. There was a significant difference between the mean partial pressure of oxygen in arterial blood (PaO2), lactate, and peripheral oxygen saturation (SpO2) values between sequential ABGs after HFNC (P <0.001). In the COPD group (n=32), there was a significant difference between initial ABG means of PaO2, lactate, and SpO2 values and sequential ABG means (p<0.001). Hypercapnic patients PaCO2 levels were significantly lower after HFNC (p<0.001), while in the COPD group there was no significant change in PaCO2 values (p=0.068).Conclusions: Treatment with HFNC produced improvement of blood gas parameters in subjects with acute respiratory failure in the emergency department (ED). These results suggest that HFNC can be used in hypercapnic patients as well as hypoxemic patients. Further randomized controlled studies required to establish the impact of HFNC in the ED.

Maximum Pao2 in the First 72 Hours of Intensive Care Is Associated With Risk-Adjusted Mortality in Pediatric Patients Undergoing Mechanical Ventilation.

A relationship between Pao2 and mortality has previously been observed in single-center studies. We performed a retrospective cohort study of the Pediatric Health Information System plus database including patients less than or equal to 21 years old admitted to a medical or cardiac ICU who received invasive ventilation within 72 hours of admission. We trained and validated a multivariable logistic regression mortality prediction model with very good discrimination (C-statistic, 0.86; 95% CI, 0.79–0.92; area under the precision-recall curve, 0.39) and acceptable calibration (standardized mortality ratio, 0.96; 95% CI, 0.75–1.23; calibration belt p = 0.07). Maximum Pao2 measurements demonstrated a parabolic (“U-shaped”) relationship with PICU mortality (Box-Tidwell p < 0.01). Maximum Pao2 was a statistically significant predictor of risk-adjusted mortality (standardized odds ratio, 1.27; 95% CI, 1.23–1.32; p < 0.001). This analysis is the first multicenter pediatric study to identify a relationship between the extremes in Pao2 values and PICU mortality. Clinicians should remain judicious in the use of oxygen when caring for children.

Comparative study between volume-controlled ventilation and pressure-controlled ventilation in prevention of postoperative pulmonary atelectasis in morbidly obese patients undergoing laparoscopic gastric sleeve surgery

BackgroundAtelectasis can result during general anesthesia from mechanical ventilation and decrease in lung volume particularly in morbidly obese patients undergoing abdominal laparoscopic sleeve surgery, which may result in the development of postoperative pulmonary complications (PPCs), including hypoxemia and pneumonia, with an increased risk of postoperative morbidity and mortality.ObjectiveTo compare between volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) in prevention of postoperative pulmonary atelectasis in morbidly obese patients undergoing laparoscopic gastric sleeve surgery.MethodsThis is a randomized prospective comparative clinical study with a total of 52 morbidly obese patients who were randomly divided into 2 groups; 26 patients in group (V) for VCV and 26 in group (P) for PCV arterial blood samples were obtained, and PaCO2, PaO2, and SaO2 were obtained and recorded. ABG analyses were also obtained 30 min, 12 h, and 24 h post-extubation, and PaCO2, PaO2, and SaO2 were obtained and recorded.ResultsThe results of this study revealed no significant differences between PCV and VCV as regards the incidence of postoperative lung atelectasis immediately postoperative (69.2% with VCV vs 61.5% with PCV, p = 0.368), 12 h postoperative (61.5% with VCV vs 53.8% with PCV, p = 0.282), and 24 h postoperative (53.8% with VCV vs 46.2% with PCV, p = 0.325). There were also no significant differences between VCV and PCV as regards baseline, intra-, and post-operative PaCO2 levels as well as baseline and postoperative SaO2 and PaO2 values. However, PCV showed better intraoperative oxygenation compared to VCV. SaO2 was 96.32% ± 1.85 and 97.25% ± 1.37 in VCV and PCV groups respectively (p = 0.027) while PaO2 was 212.75 mmHg ± 20.13 and 225.8 mmHg ± 18.69 in VCV and PCV groups respectively (p = 0.011).ConclusionDespite a slight improvement in intraoperative oxygenation parameters (PO2, SaO2) with PCV than VCV, there is no significant difference between VCV and PCV in the prevention of postoperative pulmonary atelectasis; moreover, there is no difference in postoperative oxygenation parameters in morbidly obese patients who undergo laparoscopic sleeve surgery.

Optimal Partial Pressure of Oxygen Affects Outcomes in Patients With Severe Traumatic Brain Injury.

IntroductionSevere traumatic brain injury (TBI) is a leading cause of death and disability. Not all neuronal damage occurs at the time of primary injury, but rather TBI initiates a cascade of events that leads to secondary brain injury. Oxygenation is one crucial factor in maintaining brain tissue homeostasis post-injury. We performed a retrospective review of patients admitted to a single trauma center after TBI. Statistical analysis was performed to ascertain if the measured partial pressure of oxygen (PaO₂) affected overall outcome at the time of discharge from the hospital.Materials and MethodsStatistical analysis was performed retrospectively on patients admitted with a Glasgow Coma Scale (GCS) < 8 and a diagnosis of TBI. GCS and Glasgow Outcome Scale (GOS) were calculated from physical examination findings at the time of hospital discharge or death. Patient data were separated into two groups: those with consistently higher average PaO₂ scores (≥ 150 mmHg; n = 7) and those with lower average PaO₂ scores (< 150 mmHg; n = 8). The minimum requirement to be categorized in the consistently higher group was to have an average hospital day 1 through 5 PaO₂ value of ≥ 150 mmHg.ResultsPatients with consistent hospital Day 1 through 5 PaO₂ scores of ≥ 150 mmHg had statistically significant higher GCS scores at the end of intensive care unit (ICU)-level care or hospital discharge (mean = 12, p = 0.01), compared to those in group 2 with lower PaO₂ levels (mean = 7.9). There was no statistically significant difference in GOS when comparing the two groups (p = 0.055); however, the data did show a trend toward significance.Discussion and ConclusionIn our study we analyzed patients diagnosed with TBI and stratified them into groups based on PaO₂ ≥ or < 150 mmHg. We demonstrate overall outcome improvement based on GCS with a trend toward improved GOS. The GCS showed statistical significance in patients with PaO₂ consistently ≥ 150 mmHg versus those in group 2 over the first five days of hospitalization.

Posição prona em pacientes em ventilação espontânea com insuficiência respiratória por COVID-19: relato de caso

INTRODUÇÃO: A Posição Prona (PP) geralmente é utilizada em casos de Insuficiência Respiratória Aguda (IRpA) grave, em pacientes com Síndrome da Angústia Respiratória Aguda (SARA) e em ventilação mecânica invasiva, com o objetivo de melhorar a oxigenação. Entretanto, pode ser útil em casos de IRpA leve secundária ao COVID -19 reduzindo a necessidade de ventilação mecânica invasiva e as complicações associadas ao ventilador. OBJETIVO: Descrever o relato de caso do uso da posição prona (PP) em pacientes em ventilação espontânea com Insuficiência Respiratória Leve secundária ao COVID-19. MÉTODO: Trata-se de um relato de caso de um paciente com diagnóstico de COVID-19, com IRpA leve, com dispneia, tosse, hipoxemia e dessaturação, que dentre as técnicas de tratamento utilizou um protocolo de posição prona por períodos de duas horas, duas vezes ao dia, durante todo o período de internação. RESULTADOS: O paciente apresentou hipoxemia (SPO2 -94% e PO2- 62,9), associada a dispneia (Borg 6) na admissão, tendo apresentado melhora na dispneia (Borg 4) e saturação na oximetria de pulso de 96% após 24 horas de início do protocolo. Após 48 horas apresentou melhora gasométrica com valores e SPO2 e PO2 de 96,5% e 80,6 mmHg respectivamente. CONCLUSÃO: A posição prona em pacientes em ventilação espontânea, com insuficiência respiratória leve secundária ao COVID-19 é segura e pode ser utilizada como terapia adjuvante ao tratamento desse perfil de pacientes.

Do potent immobilising-opioids induce different physiological effects in impala and blesbok?

Potent opioids are known to cause negative alterations to the physiology of immobilised antelope. How these effects differ between species has not been studied. This study aimed to compare time to recumbence and effects of opioid-based immobilisation on the physiology of impala (Aepyceros melampus) and blesbok (Damaliscus pygargus phillipsi). Eight animals of each species were immobilised, with 0.09 mg/kg etorphine and 0.09 mg/kg thiafentanil respectively, in a randomised two-way cross-over study. Variables measured and analysed by means of a linear mixed model included time to recumbence, heart rate, respiratory rate, arterial blood pressure, blood gases, lactate and glucose. In blesbok, mean time to recumbence was not significantly different with either drug (2.5 minutes and 2.2 min, respectively), but in impala thiafentanil achieved a shorter time to recumbence (2.0 min) than etorphine (3.9 min). Mean heart rates of immobilised impala were within reported physiological limits, but lower in immobilised blesbok when both opioids were used (35 beats/min to 44 beats/min vs. 104 ± 1.4 beats/min resting heart rate). Impala developed severe respiratory compromise and hypoxaemia from both opioids (overall mean PaO2 values ranged from 38 mmHg to 59 mmHg over 30 min). In contrast, blesbok developed only moderate compromise. Therefore, significantly different species-specific physiological responses to potent opioid drugs exist in blesbok and impala. Given that these different responses are clinically relevant, extrapolation of immobilising drug effects from one species of African ungulate to another is not recommended.