Background: In cardiac surgery, supraphysiological oxygen levels are frequently applied perioperatively. In this study, we examined the postoperative effect of perioperative hyperoxemia in cardiac surgery. Methods: All patients who underwent mitral valve replacement via the standard sternotomy method between 2010 and 2021 were analyzed by scanning the hospital data system. The patients were divided into 2 groups: the hyperoxemic group (partial pressure of oxygen/fraction of inspired oxygen [PAO2 /FiO2 ] >500 mmHg) (Group I) and the normoxemic group (300 mmHg < PAO2 /FiO2 < 500 mmHg) (Group II) according to the mean of 3 PAO2 /FiO2 values calculated by using 3 PAO2 and 3 FiO2 levels. Postoperative complications, the mechanical ventilation time, the need for noninvasive mechanical ventilator support, the length of intensive care unit (ICU) stay, the hospitalization period, and the mortality rate of the groups were compared. Results: A total of 78 patients were included in the study, and 53 of the patients (67. 9%) were female. The mean age of the patients was 58. 89±, 12. 60 years. The total mechanical ventilation time was significantly higher in the hyperoxemic group than in Group II (P<0. 001) (18. 18±, 12. 90 h and 11. 45±, 7. 85 h, respectively). The amount of postoperative bleeding was significantly higher in Group I (P=0. 003) (539. 47±, 201. 74 mL and 417. 50±, 186. 93 mL, respectively). The total amount of blood products administered during surgery and ICU stay was higher in Group I (P=0. 041) (3. 55±, 1. 59 units and 2. 87±, 1. 89 units, respectively). Conclusion: We observed that the group with hyperoxemia during cardiopulmonary bypass had a higher amount of postoperative bleeding and the need for transfusion, as well as a longer duration of mechanical ventilation and intensive care.

Background: It is necessary to determine the value of PAO2 and PaCO2 in COPD patients for diagnosis the severity of chronic bronchitis diseases and their separation from other diseases.For the diagnosis of COPD diseases and their separation from other diseases and for having a criterion for treatment with oxygen, we need to know the amount of PAO2 and PaCO2 in patients; ABG is an invasive and difficult procedure.Materials and Methods: This cross sectional study was carried out on 118 consecutive patients with chronic bronchitis referring to Afshar hospital in Yazd in order to determine the correlation between spirometry FEV1 and ABG parameters.Results: The study population included 82 (69.5%) males and 36(30.5%) females with the mean age of 71.6±9 years. The mean FEV1 (% pred.) was 42.88±15.12, mean PAO2 was 55.31±13.51 mmHg and mean PaCO2 was 51.64±10.56 mmHg. FEV1 was positively correlated with PAO2 (r=0.418, p<0.0001) and inversely correlated with PaCO2 (r= -0.533, p<0.0001).Conclusion: One could establish a reliable equation indicating the correlation between FEV1 and PAO2 as well as PaCO2 in patient with chronic bronchitis.

Introduction: Respiratory failure is one of the most important related factors in morbidity and mortality of neonates with congenital diaphragmatic hernia (CDH). Determining indexes that could ultimately and perceivably predict the disease severity and its prognosis is crucial.This study aimed to evaluate the predictive value of PAO2/Fio2 ratio (P/F ratio) in neonates with CDH.Materials and methods: In this retrospective study, medical records of all neonates with CDH admitted to Alzahra (Isfahan, Iran) hospital from 2005 to 2015 were checked. Thirty-five neonates with CDH were studied. Data collected were: gestational age, sex, weight, PAO2, Fio2 and clinical outcome.Results: In this survey 24 neonates with CDH were studied. The mean P/F ratio in the survival group was 2.12±0.90 and in the non-survival group, 1.38 ±0.48. According to these results the P/F ratio in the survival group was higher than the other group and this difference was statistically significant (P=0.02). Based on the ROC curve, the specificity of P/F ratio in predicting survival is 72.2 percent and its sensitivity in predicting death is 80 percent.Conclusion: P/F ratio is a useful index for predicting the outcome of neonates with CDH.

Background: Due to the effects of prone position in improving pulmonary function by Increasing FRC (Functional Residual Capacity), and blood distribution alterations in dependant and non-dependant regions of the lung. We decided to evaluate the effect of position on patients with ARDS in ICU. Material and Methods: In this series study. Hemodynamic indicators in addition to PAO2 of 10 ICU patients with ARDS whom in spite of mechanical support with 100% 02 and maximum tolerable (PEEP) had a PAO2 / FIO2 ratio of less than 300. Were measured 30 min before prone positioning and 30 min. 2 hrs and 6 hrs after prone positioning without any changes in ventilator setting and FIO2.Results: Mean heart rate was increased and systolic and diastolic pressures were decreased. At 30 min after positioning in comparison to 30 min before position changing but remained unchanged through the next 2 measurements. PAO2 was not increased significantly after 30 min of positioning but after 2 and 6 hrs. It was significantly increased. There were also significant differences between the 2 and 6 hrs values of PAO2. Conclusion: Prone position improves respiration in patients with impaired gas exchange due to ARDS.

Background: In patients under mechanical ventilation, the patient's position is one of the factors affecting the efficiency of respiratory gas exchange. The aim of this study was to compare the level of arterial blood gas pressure and the percentage of arterial oxygen saturation in the supine position with the lateral position in patients with ventilator-associated pneumonia. Methods: In a clinical trial study with a sample size of 50 patients with ischemic stroke under mechanical ventilation admitted to the intensive care unit of Kashani hospital affiliated to Shahrekord University of Medical Sciences, Shahrekord, Iran, in 2019 were selected using convenience sampling method. Oxygen saturation percentage was measured by a pulse oximeter in patients lying on their backs and then, on their sides for two hours,arterial blood pressure and carbon dioxide levels were measured with arterial blood sample by laboratory device, and recorded in the relevant checklist as well. Findings: In both supine and lateral positions, the mean arterial oxygen pressure and the percentage of hemoglobin oxygen saturation were not significantly different (P > 0. 050),while the arterial carbon dioxide pressure in the lateral position was significantly lower than the supine position (P = 0. 008). Conclusion: The lateral position has no significant effect on the improvement of arterial blood gases and oxygen saturation in patients with pneumonia due to mechanical ventilation,but has significantly reduce the pressure of carbon dioxide.

Background & Aims: Diagnostic criteria for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) requires acute onset of disease, chest radiograph demonstrating bilateral pulmonary infiltrates, lack of significant left ventricular dysfunction and PAO2/fio2(PF) ratio£300 for ALI or£200 for ARDS. And the latter one requires invasive arterial sampling. Measurement spo2 by pulse oxi metry and calculation spo2/Fio2 (SF) ratio may be a reliable non invasive alternative to the PF ratio.Materials & Methods: In this cross sectional study, 70 patient diagnosed for ALI or ARDS admitted in Tabriz children's hospital PICU were enrolled. Then spo2, Fio2, PAO2 charted within 5 minutes were measured and the ratio of SF and PF were calculated and compared. SF threshold the values were determined to replacement PF ratio for diagnose ARDS and ALI.Results: The relationship between SF and PF ratio was described by the following regression equation SF=57+0.61PF (P<0.001). SF ratios of 181 and 235 corresponded of PF ratio 300 and 200. The ALI SF cutoff of 235 had 57% sensitivity and 100% specificity, and ARDS, SF cutoff of 181 had 71% sensitivity and 82% specificity.Conclusion: SF ratio is a reliable noninvasive marker for PF ratio to identify children with ALI or ARDS. And can be replaced pulse oximetry by arterial blood sampling.

End-stage kidney disease has a high prevalence in patients undergone Coronary Artery Bypass Grafting (CABG) and could cause a wide spectrum of morbidities, due to deep water and electrolyte or acid-base impairments. The aim of this study was to assess the effect of low Creatinine Clearances (ClCr) on arterial oxygenation defect, as common post-CABG morbidity. The study was conducted as a prospective cohort, the pure on pump CABG patients were grouped based on their preoperative ClCr to groups A (ClCr≥ 60) and B (ClCr<60). Postoperatively, the PAO2/FiO2 values in 1 hour after ICU admission and 4 hours after extubation, intubation time duration, duration of ICU stay and high concentration oxygen demand were compared. Among 229 patients who remain in the study, 121 were in group A, and 108 in B group. Except for age, weight, height, BMI, and pump time, other demographic and independent variables were similar between two groups. The higher values of PAO2/FiO2 and PAO2, 1 hour after ICU admission and 4 hours after extubation in group B, were not statistically significant, while SpO2 value, 1 hour after ICU admission was higher in group B (98. 19± 1. 37) in compare with group A (97. 78± 1. 57) (P=0. 040). Intubation time duration (10. 85 in A vs. 12. 79 in B; P=0. 306), duration of ICU stay (39. 04 in A vs. 43. 09 in B; P=0. 114) and high concentration oxygen demand (2. 5% in A vs. 3. 8% in B; P=0. 089) were similar between groups of study. Lower Preoperative ClCr values do not deteriorate post-CABG arterial oxygenation.

Background and Objective: In order to determine the Hypoxemia and prognosis of patients with covid-19 hospitalized in the intensive care unit, reliable oxygen supply indicators are needed. In this situation, the examination of the percentage of arterial oxygen saturation (SaO2) and arterial oxygen pressure (PAO2), as well as their relationship, may be helpful. Materials and Methods: This descriptive-cross-sectional study examined 1, 121 patients with covid-19 hospitalized in the intensive care unit of hospitals affiliated with Hamadan University of Medical Sciences. Data were collected through a researcher-made checklist, including age, gender, history of smoking and drug use, underlying disease, duration of hospitalization, the outcome of hospitalization, and hemoglobin listed in the patient's medical records. Moreover, SaO2 and PAO2 were examined in the first arterial blood analysis report after admission to the hospital. Results: A positive and significant correlation was observed between SaO2 and PAO2 (r=0. 733 and P<0. 001). SaO2 significantly predicted PAO2 in COVID-19 patients (β, =63. 51, R2=0. 630, P<0. 001). Furthermore, the duration of hospitalization had a positive and significant correlation with PAO2 (r=0. 112, P<0. 001) and SaO2 (r=0. 063, P=0. 034). Conclusion: The measurement of the percentage of oxygen saturation and arterial oxygen pressure through arterial blood gas analysis is more accurate in diagnosing Hypoxemia in covid-19 patients. They are better indicators to determine the prognosis of critically ill patients.