Objective To observe the difference between hematocrit (Hct) and albumin (Alb) levels (Hct－Alb) in hemorrhagic shock and septic shock, and to provide a quick and simple method for differentiating hemorrhagic shock from septic shock. Methods 270 shock patients admitted to intensive care unit (ICU) of the First Affiliated Hospital of Kunming Medical University from August 2012 to August 2018, including 124 patients with hemorrhagic shock and 148 patients with septic shock, were enrolled. 148 patients underwent routine physical examination served as a control healthy group. General information such as gender, age, and body mass index (BMI) of the patient were collected. Hct and serum Alb levels on the day of physical examination or onset before blood products transfusion were recorded, and the Hct－Alb difference was calculated. The Hct－Alb differences among the three groups were compared. The receiver operating characteristic (ROC) curve was plotted to analyze the differential diagnosis value of Hct－Alb difference for shock type. Results All patients were enrolled in the final analysis. Compared with the healthy control group, the patients with hemorrhagic and septic shock were older (years: 50.0±19.8, 59.9±16.9 vs. 42.5±13.6, both P < 0.01), and those patients with septic shock was significantly older than those with hemorrhagic shock (years: 59.9±16.9 vs. 50.0±19.8, P < 0.01). There were no significant differences in gender or BMI among the three groups. Compared with the healthy control group, Hct and Alb values in hemorrhagic shock group and septic shock group were significantly decreased [Hct: (27.9±8.4)%, (35.5±7.1)% vs. (47.0±4.4)%, Alb (g/L): 28.9±7.1, 23.3±5.8 vs. 45.4±4.3, all P < 0.01]. The Hct－Alb difference in the septic shock group was significantly higher than that in the healthy control group (12.1±7.5 vs. 1.6±5.9, P < 0.01), but no significant difference was found between hemorrhagic shock group and healthy control group (-0.9±5.3 vs. 1.6±5.9, P > 0.05). Compared with hemorrhagic shock group, the Alb level in septic shock group was significantly decreased (g/L: 23.3±5.8 vs. 28.9±7.1, P < 0.01), and Hct and Hct－Alb difference were significantly increased [Hct: (35.5±7.1)% vs. (27.9±8.4)%, Hct－Alb difference: 12.1±7.5 vs. -0.9±5.3, both P < 0.01]. It was shown by ROC curve analysis that the area under the ROC curve (AUC) for diagnosing hemorrhagic shock and septic shock was 0.366 and 0.867, indicating that Hct－Alb difference had diagnostic value only for septic shock. When the best cut-off value of Hct－Alb difference was 6.8, the sensitivity was 79.5% for diagnosing septic shock, and the specificity was 79.7%, the positive predict value was 0.80, the negative predict value was 0.80, the positive likelihood ratio was 3.916, the negative likelihood ratio was 0.257. Conclusions The Hct－Alb difference in patients with septic shock is higher than that in patients with hemorrhagic shock. The Hct－Alb difference is highly accurate in diagnosing septic shock. When the Hct－Alb difference is greater than 6.8, it can be used for differential diagnosis of hemorrhagic shock and septic shock.

Objective:To investigate and evaluate if pulse oxygen saturation/fraction of inhaled oxygen (SpO 2/FiO 2) can be used, as replacement of arterial partial pressure of oxygen/fraction of inhaled oxygen (PaO 2/FiO 2), to assess oxygenation in acute respiratory distress syndrome (ARDS) patients at different high altitudes in Yunnan Province, and to find a rapid and non-invasive method for the diagnosis of ARDS at different altitudes. Methods:Patients with ARDS at different high altitudes in Yunnan Province from January 2019 to December 2020 were enrolled. The patients were divided into three groups according to different altitudes, and received different oxygen therapies according to their respective medical conditions. Group 1 consisted of patients with moderate to severe ARDS from the department of critical care medicine of the First Affiliated Hospital of Kunming Medical University (average altitude approximately 1 800 m), and received mechanical ventilation to maintain SpO 2 of 0.90-0.96 with a low FiO 2 for more than 30 minutes, and SpO 2, FiO 2, PaO 2 were recorded. Group 2 consisted of patients with moderate to severe ARDS at the department of critical care medicine of People's Hospital of Diqing Tibetan Autonomous Prefecture (mean altitude about 3 200 m), and received oxygen with an attached reservoir mask to maintain SpO 2 of 0.90-0.96 for 10 minutes, and then SpO 2, FiO 2, and PaO 2 were recorded. Group 3 consisted of patients with mild to moderate-severe ARDS who admitted to the emergency department of the People's Hospital of Lijiang (average altitude approximately 2 200 m); when SpO 2 < 0.90, patients received oxygen with the oxygen storage mask, and the FiO 2 required to maintain SpO 2 ≥ 0.90 was recorded, and SpO 2, FiO 2, PaO 2 were recorded after oxygen inhalation for 10 minutes. Spearman coefficient was used to analyze the correlation between SpO 2/FiO 2 and PaO 2/FiO 2 in each group. Linear analysis was used to derive the linear equation between SpO 2/FiO 2 and PaO 2/FiO 2, and to evaluate arterial pH, arterial partial pressure of carbon dioxide (PaCO 2), FiO 2, tidal volume (VT), positive end-expiratory pressure (PEEP) and other related factors which would change the correlation between SpO 2/FiO 2 and PaO 2/FiO 2. The receiver operator characteristic curve (ROC curve) was plotted to calculate the sensitivity and specificity of using SpO 2/FiO 2 instead of PaO 2/FiO 2 to assess oxygenation of ARDS patients. Results:Group 1 consisted of 24 ARDS patients from whom 271 blood gas analysis results were collected; group 2 consisted of 14 ARDS patients from whom a total of 47 blood gas analysis results were collected; group 3 consisted of 76 ARDS patients, and a total of 76 blood gas analysis results were collected. The PaO 2/FiO 2 (mmHg, 1 mmHg = 0.133 kPa) in groups 1, 2 and 3 were 103 (79, 130), 168 (98, 195) and 232 (146, 271) respectively, while SpO 2/FiO 2 were 157 (128, 190), 419 (190, 445) and 319 (228, 446) respectively. Among the three groups, patients in group 1 had the lowest PaO 2/FiO 2 and SpO 2/FiO 2, while patients in group 3 had the highest. Spearman correlation analysis showed that PaO 2/FiO 2 was highly correlated with SpO 2/FiO 2 in groups 1, 2 and 3 ( r values were 0.830, 0.951, 0.828, all P < 0.05). Regression equation was fitted according to linear analysis: in group 1 SpO 2/FiO 2 = 58+0.97×PaO 2/FiO 2 ( R2 = 0.548, P < 0.001) ; in group 2 SpO 2/FiO 2 = 6+2.13×PaO 2/FiO 2 ( R2 = 0.938, P < 0.001); in group 3 SpO 2/FiO 2 = 53+1.33×PaO 2/FiO 2 ( R2 = 0.828, P < 0.001). Further analysis revealed that PEEP, FiO 2, and arterial blood pH could affect the correlation between SpO 2/FiO 2 and PaO 2/FiO 2. ROC curve analysis showed that the area under ROC curve (AUC) was 0.848 and 0.916 in group 1 with moderate to severe ARDS; based on the regression equation, the corresponding SpO 2/FiO 2 cut-off values at a PaO 2/FiO 2 of 100 mmHg and 200 mmHg were 155, 252 with a sensitivity of 84.9% and 100%, specificity of 87.2% and 70.6%, respectively. Patients with moderate to severe ARDS in group 2 (AUC was 0.945 and 0.977), the corresponding SpO 2/FiO 2 cut-off values at PaO 2/FiO 2 of 100 mmHg and 200 mmHg were 219 and 432 with the sensitivity of 100% and 85.2%, specificity of 82.5% and 100%, respectively. Patients with mild to moderate-severe ARDS in group 3 (AUC was 0.903 and 0.936), the corresponding SpO 2/FiO 2 cut-off values at a PaO 2/FiO 2 of 200 mmHg and 300 mmHg were 319 and 452 with the sensitivity of 100% and 100%, specificity of 80.9% and 86.2%, respectively. Conclusion:SpO 2/FiO 2 and PaO 2/FiO 2 in ARDS patients at different high altitudes in Yunnan Province have a good correlation, and non-invasive SpO 2/FiO 2 can be used to replace PaO 2/FiO 2 to assess the oxygenation in ARDS patients.