Comparison of pulse oxygen saturation/fraction of inhaled oxygen and arterial partial pressure of oxygen/fraction of inhaled oxygen in the assessment of oxygenation in acute respiratory distress syndrome patients at different high altitudes in Yunnan Province / 中华危重病急救医学

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.

Feasibility of pulse oxygen saturation for the condition evaluation of acute respiratory distress syndrome patients in the Lijiang region / 中华危重病急救医学

Objective:To explore the feasibility of using pulse oxygen saturation (SpO 2) to evaluate the condition of patients with acute respiratory distress syndrome (ARDS) in the Lijiang region. Methods:Patients with ARDS who visited the department of emergency of People's Hospital of Lijiang from August to December 2020 were selected as study subjects. Patients were divided by severity into mild ARDS group [200 mmHg (1mmHg = 0.133 kPa)≤oxygenation index (PaO 2/FiO 2, P/F)≤300 mmHg] and moderate to severe ARDS group (P/F≤200 mmHg). The general condition, clinical diagnosis, arterial blood gas analysis results of the patients were recorded, and the differences of the above indexes between the two groups of ARDS were compared. Spearman correlation analysis was used to analyze the correlation between SpO 2 and arterial oxygen saturation (SaO 2). SpO 2 was carried into the Ellis equation and the Rice equation to calculate the derived P/F and analyze the correlation between the derived P/F and the P/F measured in arterial blood gas analysis; receiver operator characteristic curve (ROC curves) were plotted, the sensitivity and specificity of SpO 2/fraction of inspiration oxygen (SpO 2/FiO 2, S/F) instead of P/F to assess oxygenation in patients with ARDS was calculated. To evaluate the feasibility of SpO 2 for the condition evaluation of patients with ARDS in the Lijiang region. Results:Compared with the mild ARDS group, the arterial partial pressure of oxygen (PaO 2), SaO 2 and hemoglobin (Hb) were significantly decreased in the moderate to severe ARDS group [PaO 2 (mmHg): 50.5 (39.3, 56.5) vs. 60.0 (55.0, 67.5), SaO 2: 0.86 (0.73, 0.91) vs. 0. 93 (0.90, 0.96), Hb (g/L): 142±27 vs. 156±24, respectively, all P < 0.05]. Correlation analysis revealed a significant positive correlation between SpO 2 and SaO 2 in ARDS patients residing at high altitude ( R = 0.650, P = 0.000). The P/F derived by the Rice formula was significantly and positively correlated with the P/F derived from arterial blood gas analysis ( R = 0.802, P = 0.000). The deduced P/F in mild and moderate to severe ARDS groups were all significantly correlated with the measured P/F ( R values were 0.562, 0.647, both P = 0.000). The P/F derived using the Ellis formula showed a significant positive correlation with the P/F derived from arterial blood gas analysis ( R = 0.822, P = 0.000). The deduced P/F of mild ARDS group and moderate to severe ARDS group were all positively correlated with the measured P/F ( R values were 0.556, 0.589, P values were 0.000, 0.010). There was a significant positive correlation between S/F and P/F in ARDS patients ( R = 0.828, P = 0.000), and the regression equation was S/F = 1.33 P/F+52.41. ROC curve analysis showed that S/F had some predictive value for patients with mild and moderate to severe ARDS, and area under ROC curve (AUC) and 95% confidence interval (95% CI) were 0.903 (0.829-0.977), 0.936 (0.870-1.000), both P = 0.000. When the cut-off value was 452 mmHg, S/F had a sensitivity of 100% and a specificity of 80.9% for predicting mild ARDS. When the cut-off value was 319 mmHg, S/F predicted moderate to severe ARDS with 95.1% sensitivity and 86.2% specificity. Conclusions:At high altitude, SpO 2 and SaO 2 have been correlated in patients with ARDS, and P/F derived using SpO 2 and measured P/F were significantly correlated in patients with ARDS, especially in those with moderate to severe ARDS. SpO 2 may be useful in the assessment of severity of illness in patients with ARDS at high altitude.

Levels and clinical significance of serum SP-D and MBL in infants with cytomegalovirus pneumonia / 国际儿科学杂志

Objective To investigate the levels of serum surfactant protein D (SP-D) and mannosebinding lectin (MBL) in infants with cytomegalovirus (CMV) pneumonia with the severity of disease.Methods A total of 101 hospitalized infants with CMV pneumonia were enrolled from January 2011 to December 2012.These patients were divided as the severe pneumonia group (n =48) and the mild pneumonia group (n =53) according to physical sign of lung and complication.Another 55 infants who were hospitalized in the same period with non-infectious diseases were used as the control group.Serum levels of SP-D and MBL were detected by enzyme-linked immunosorbent assay.Blood gas analyzer was used to measure arterial partial pressure of oxygen (PaO2) of the blood in severe patients.Results The mean serum SP-D levels in the severe pneumonia group [(150.08 ±52.59)ng/ml] and the mild pneumonia group [(109.67 ±31.39)ng/ml] were significantly higher than those in control group [(41.33 ± 16.42) ng/ml] (P ＜ 0.01), and higher in the severe pneumonia group than in the mild pneumonia group (P ＜ 0.01).However, there was no significant difference in serum MBL between all groups (P ＞ 0.05).In severe patients, serum SP-D levels were negatively correlated with PaO2 (r =-0.565, P ＜ 0.01).Conclusion Serum SP-D is associated with the severity of CMV pneumonia, but MBL shows no relation.The serum SP-D levels has an important clinical significance in judgment the sererity of infants with CMV pneumonia.

Effect of nasal continuous positive airway pressure and Bi-phase positive airway pressure on oxygen exchange indexes in newborns with mild to moderate neonatal respiratory distress syndrome / 中华实用儿科临床杂志

Objective To observe the effect of nasal continuous positive airway pressure (nCPAP) and Biphase positive airway pressure (BIPAP) on the oxygen exchange indexes in newborns with mild to moderate neonatal respiratory distress syndrome (NRDS).Methods After infusion of pulmonary suffactant into lung bilaterally,116 cases with mild to moderate NRDS were treated with nCPAP(nCPAP group,n =75) and BIPAP(BIPAP group,n =41) respectively.Oxygen exchange indexes including arterial partial pressure of oxygen [pa (O2)],modified oxygenation index (P/F),alveolar-arterial oxygen tension difference (A-aDO2),respiratory index (RI),artery/alveolar oxygen partial pressure ratio[pa (O2)/pA (O2)] and pulmonary shunt fraction (Qs/Qt) were measured or calculated at 0 (before treatment),2,8 and 24 h after being treated with nCPAP or BIPAP.Results Six different oxygen exchange indexes of Pa (O2),P/F,A-aDO2,RI,pa (O2)/pA(O2) and Qs/Qt in both groups didn't show statistical significance at 0 hour:pa(O2) (kPa) (6.1 ±0.6 vs 6.1 ±0.6,t =0.11,P ＞0.05),P/F(kPa) (15.59 ± 1.45 vs 15.71 ± 1.45,t =1.59,P ＞ 0.05),A-aDO2(kPa)(6.04 ±0.64 vs 6.24 ±0.69,t =1.59,P ＞0.05),RI(6.0 ± 1.0 vs 6.2 ± 1.1,t =1.35,P ＞ 0.05),p,(O2)/pA(O2) (0.24 ±0.02 vs 0.25 ±0.03,t =1.63,P ＞0.05)and Qs/Qt(％)(11.9±1.6 vs 11.6 ± 1.6,t =1.10,P ＞ 0.05).A-aDO2,RI,pa (O2)/pA (O2) and Qs/Qt of BIPAP group had more improvement than those of nCPAP at 2 and 24 h,and oxygen exchange indexes at 2 h of BIPAP group and those of nCPAP group were:A-aDO2 (kPa) (3.83 ±0.49 vs 4.24 ± 0.67,t =18.26,P ＜ 0.05),RI(2.7 ± 0.5 vs 3.3 ±0.7,t =20.59,P ＜ 0.05),p,(O2)/pA(O2) (0.35 ±0.03 vs 0.32 ±0.04,t =15.35,P ＜0.05) and Qs/Qt(％) (8.8 ± 1.6 vs 9.8 ±2.0,t =7.68,P ＜ 0.05) ; 24 h indexes in BIPAP group and the indexes of nCPAP group were:A-aDO2 (kPa) (2.29 ± 1.19 vs 3.07 ± 1.67,t=18.43,P ＜0.05),RI(1.4 ±1.4 vs 2.3 ± 1.6,t=25.02,P ＜0.05),pa(O2)/pA(O2) (0.49 ±0.10 vs 0.42 ±0.11,t =14.96,P ＜0.05) and Qs/Qt(％) (6.5 ±3.0 vs 8.5 ±4.4,t =9.59,P ＜0.05).pa(O2) and P/F of both groups didn't show statistical difference significantly [Pa (O2)(kPa) (12.6 ± 1.0 vs 12.7 ± 1.0,t =3.76,P ＞ 0.05),P/F(28.49 ± 3.17 vs 31.85 ± 2.85,t =3.76.P ＞ 0.05)].Nineteen cases in nCPAP group needed invasive mechanical ventilation,and only 3 cases in BIPAP group underwent the procedure;there was a significant difference (x2 =4.01,P ＜ 0.05).Oxygen exchange indexes in both groups were gradually improved from 2 h,8 h to 24 h,but 22 deteriorated cases showed no improvement,who underwent invasive ventilation.Positive end-expiratory pressure (PEEP) positive airway pressure (EPAP) was (0.42 ± 0.19) kPa in BIPAP group,and (0.56 ± 0.23) kPa in nCPAP group (t =3.45,P ＜ 0.01).Conclusions 1.BIPAP and nCPAP can improve the ability of oxygen exchange in newborns with mild to moderate NRDS,but BIPAP is more effective than nCPAP,which can shorten the possibility of invasive ventilation and reduce the PEEP level.2.p,(O2),P/F,pa (O2)/pA (O2) and RI may be more suitable for evaluating oxygen exchange for neonatal NRDS.

Effect of inhaled low density nitric oxyde in pig' s pulmonary thromboembolism / 中华急诊医学杂志

Objective To investigate the mechanism and significance of low concentration nitric oxide (NO) inhalation in the treatment of pulmonary thromboembelism in swine. Method The pulmonary thromboem-bolism(PTE) model was made in 15 healthy infantile swines which were subsequently assigned to either control group (n = 8) or NO group (n = 7). Swines of the control group were not treated with any medicine, while 10 ppm of NO was administered by continuous inhalation for 2 hours to swines of NO group. Volume of physiological dead space (VDphy), volume of alveolar dead space (VDalv), intrapulmonary shunt (Qs/Qt), mean pulmonary arterial pressure (PAP), systolic blood pressure (SBP), heart rate (HR), cardiac output (CO), arterial blood pH (pH), arterial partial pressure of carbon dioxide (PaCO2) and arterial partial pressure of oxygen (PaO2) were measured 30 min before and 0 min, 30 min, 60 min, 120 min and 180 min after establishment of VIE. Results The post-FIE VDphy, VDalv, Qs/Qt and PAP in both groups increased markedly after PTE compared with the cor-responding pre-PTE measurements (P < 0.01). Post-FIE PaO2 of both groups decreased significandy (P <0.05 and P <0.01), while significance difference was found between pre- and post-PTE HR, SBP, CO, pH or PaCO2 in neither groups (P > 0.05). Both post-PTE PAP and VDalv in NO group were markedly lower(P <0.05 and P <0.01) and beth PaCO2 and PaO2 were much higher than those of the control group (P <0.05). No signi-fieant difference were found in other measurements between two groups. Conclusions Pulmonary arterial pressure may be lowered, alveoli dead space may be reduced and PaCO2 increased by low concentration NO inhalation for the treatment of PIE without decline in haemodynamic status.