Pulmonary Oxygenation Function Research Articles

Identifying the link between serum VEGF and KL-6 concentrations: a correlation analysis for idiopathic pulmonary fibrosis interstitial lung disease progression.

Idiopathic pulmonary fibrosis interstitial lung disease (IPF-ILD) is a progressive lung disease characterized by excessive collagen deposition and fibrotic changes in the lungs. Identifying reliable serum markers that correlate with disease progression is crucial for diagnosis and prognosis. This study aimed to explore the association between serum markers KL-6 and VEGF and IPF-ILD. Specifically, it assessed their correlation with PaO2, a measure of pulmonary gas function, to provide diagnostic and prognostic indicators. Patients with IPF-ILD were included, and their serum levels of KL-6 and VEGF were measured. Correlations with fibrotic damage and PaO2 were analyzed using statistical methods. The analysis confirmed a positive correlation between the serum marker KL-6 and the degree of fibrotic damage in IPF-ILD. On the other hand, the serum marker VEGF was found to promote disease progression. In terms of correlation with PaO2, both KL-6 and VEGF demonstrated high sensitivity and specificity. Specifically, the correlation between KL-6 and PaO2 suggests that it can be used as a reliable indicator to assess the status of pulmonary oxygenation function in patients with ILD. The correlation between VEGF and PaO2 helps to understand its role in the progression of IPF-ILD and provides an important basis for predicting patient prognosis. This study confirmed the correlation between KL-6 and VEGF with IPF-ILD and their association with PaO2. KL-6 and VEGF demonstrated high specificity and sensitivity in diagnosing, monitoring, and predicting prognosis in IPF-ILD. These findings contribute to our understanding of the disease and have clinical implications for diagnosis and prognostication.

Evaluation of pragmatic oxygenation measurement as a proxy for Covid-19 severity

Choosing optimal outcome measures maximizes statistical power, accelerates discovery and improves reliability in early-phase trials. We devised and evaluated a modification to a pragmatic measure of oxygenation function, the S/F ratio. Because of the ceiling effect in oxyhaemoglobin saturation, S/F ratio ceases to reflect pulmonary oxygenation function at high {S}_{p}{O}_{2} values. We found that the correlation of S/F with the reference standard ({P}_{a}{O}_{2}/{F}_{I}{O}_{2} ratio) improves substantially when excluding {S}_{p}{O}_{2} > 0.94 and refer to this measure as S/{F}_{94}. Using observational data from 39,765 hospitalised COVID-19 patients, we demonstrate that S/{F}_{94} is predictive of mortality, and compare the sample sizes required for trials using four different outcome measures. We show that a significant difference in outcome could be detected with the smallest sample size using S/{F}_{94}. We demonstrate that S/{F}_{94} is an effective intermediate outcome measure in COVID-19. It is a non-invasive measurement, representative of disease severity and provides greater statistical power.

A randomized controlled trial of positive end-expiratory pressure on pulmonary oxygenation and biventricular function in esophageal cancer patients receiving one-lung ventilation under a lower FiO2

Arterial oxygenation is often impaired during one-lung ventilation (OLV), due to both pulmonary shunt and atelectasis. Lower fraction of inspiration O2 (FiO2) may reduce inflammation and complications, but may increase the risk of hypoxemia. The aim of this randomized controlled parallel trial was to analyze whether higher positive end-expiratory pressure (PEEP) could improve oxygenation and maintain lower levels of inflammation during OLV under a lower FiO2. One hundred and twenty patients with selective thoracotomy for esophageal cancer (EC) were classified randomly into four groups on a ratio of 1:1:1:1 using a computer-generated list, including Group A (FiO2 =0.6, PEEP =0), Group B (FiO2 =0.6, PEEP =5 cmH2O), Group C (FiO2 =1.0, PEEP =8 cmH2O), and Group D (FiO2 =1.0, PEEP =10 cmH2O). The oxygenation and pulmonary shunt were primary outcomes. Haemodynamics, respiratory mechanics, serum IL-6 and IL-10 levels, and complications were taken as secondary outcomes. Follow-up was terminated until discharge. Two patients in Group A and two in Group D were excluded due to hypoxemia and hypotension, respectively. Then the data of 116 patients (Group A =28, Group B =30 Group C =30, and Group D =28) were assessed for final analysis. Compared with Group B, the partial pressure of oxygen (PaO2) and dynamic compliance during OLV in Group D were significantly increased from 15 minutes to 60 minutes, while pulmonary shunt was significantly decreased (P>0.05). Patients in Group D had higher levels of central venous pressure (CVP) and airway pressure (Paw) during OLV and higher levels of IL-6 and IL-10 after OLV compared with Group B (P>0.05). No statistical differences were found in oxygen saturation (SaO2), PvO2 (partial pressure of oxygen in venous blood), partial pressure of end-tidal carbon dioxide (ETCO2), partial pressure of carbon dioxide in artery (PaCO2), heart rate (HR), mean arterial pressure (MAP), and complications among the four groups (P>0.05). Higher PEEP increased the oxygenation under 60% O2 during OLV. However, the haemodynamics and respiratory mechanics changed, and the levels of inflammation increased. A higher PEEP under 60% O2 during OLV is not recommended. Chinese Clinical Trial Registry ChiCTR1900024726.

Machine Learning Algorithm-Based Analysis of Efficacy of Pulmonary Surfactant Combined with Mucosolvan in Meconium Aspiration Syndrome of Newborns through Ultrasonic Images

Objective. The study aimed to explore the efficacy of pulmonary surfactant (PS) combined with Mucosolvan in the diagnosis of meconium aspiration syndrome (MAS) in newborns through ultrasonic images of lung based on machine learning. Methods. 138 cases of infants with MAS were selected as the research subjects and randomly divided into PS group (n = 46), Mucosolvan group (n = 46), and combination group (n = 46). Then, ultrasonic images based on machine learning algorithm were used for examination. On the basis of conventional treatment, the PS group accepted intratracheal PS drip treatment with 100 mg/kg. For the Mucosolvan group, 7.5 mg/kg of Mucosolvan was added with 50 g/L glucose, which was diluted to 3 mL. Then, the mixture was injected intravenously with a micropump for more than 5 min. The combination group received combined treatment of PS and Mucosolvan. If there was no relief or the symptoms aggravated after 12 h of PS treatment, the patient should be treated again. 7.5 mg/kg/d of Mucosolvan was given for 7 days. Mechanical ventilation time, hospitalization time, oxygenation index (OI) before treatment, at 3 d and at 7 d after treatment, and arterial/alveolar oxygen ratio (a/APO2) of the three groups were detected and compared. Besides, in-hospital mortality and complication rate of the three groups were statistically compared. Results. Ultrasonic image edge detection based on machine learning algorithm was more condensed and better than Sobel operator. Compared with the PS group and the Mucosolvan group, treatment efficiency, OI at 3 d and at 7 d after treatment, and a/APO2 of combination group were increased. Mechanical ventilation time and hospitalization time of the combination group were shortened, and mortality rate of the combination group was reduced ( P < 0.05). Compared with the situation before treatment, OI at 3 d and at 7 d after treatment and a/APO2 of the combination group were increased, and OI at 7 d after treatment and a/APO2 of the PS group and the Mucosolvan group were increased ( P < 0.05). Curative effect, mechanical ventilation time, hospitalization time, OI before and after treatment, a/APO2, and mortality rate during hospitalization of the PS group and the Mucosolvan group had no significant difference ( P > 0.05). There was no significant difference in the complications rates in the three groups ( P > 0.05). Conclusion. Pulmonary ultrasound based on machine learning algorithm can be used in the diagnosis of MAS in neonates. PS combined with Mucosolvan is feasible and safe in treating neonatal MAS and effectively improves the pulmonary oxygenation function. Therefore, it is worthy of clinical application.

Lung-protective mechanical ventilation for patients undergoing abdominal laparoscopic surgeries: a randomized controlled trial

BackgroundPneumoperitoneum and Trendelenburg position in laparoscopic surgeries could contribute to postoperative pulmonary dysfunction. In recent years, intraoperative lung-protective mechanical ventilation (LPV) has been reportedly able to attenuate ventilator-induced lung injuries (VILI). Our objectives were to test the hypothesis that LPV could improve intraoperative oxygenation function, pulmonary mechanics and early postoperative atelectasis in laparoscopic surgeries.MethodsIn this randomized controlled clinical trial, 62 patients indicated for elective abdominal laparoscopic surgeries with an expected duration of greater than 2 h were randomly assigned to receive either lung-protective ventilation (LPV) with a tidal volume (Vt) of 7 ml kg− 1 ideal body weight (IBW), 10 cmH2O positive end-expiratory pressure (PEEP) combined with regular recruitment maneuvers (RMs) or conventional ventilation (CV) with a Vt of 10 ml kg− 1 IBW, 0 cmH2O in PEEP and no RMs. The primary endpoints were the changes in the ratio of PaO2 to FiO2 (P/F). The secondary endpoints were the differences between the two groups in PaO2, alveolar-arterial oxygen gradient (A-aO2), intraoperative pulmonary mechanics and the incidence of atelectasis detected on chest x-ray on the first postoperative day.ResultsIn comparison to CV group, the intraoperative P/F and PaO2 in LPV group were significantly higher while the intraoperative A-aO2 was clearly lower. Cdyn and Cstat at all the intraoperative time points in LPV group were significantly higher compared to CV group (p < 0.05). There were no differences in the incidence of atelectasis on day one after surgery between the two groups.ConclusionsLung protective mechanical ventilation significantly improved intraoperative pulmonary oxygenation function and pulmonary compliance in patients experiencing various abdominal laparoscopic surgeries, but it could not ameliorate early postoperative atelectasis and oxygenation function on the first day after surgery.Trial registrationhttps://www.clinicaltrials.gov/identifier: NCT04546932 (09/05/2020).

Effects of Inhaled Iloprost on Lung Mechanics and Myocardial Function During One-Lung Ventilation in Chronic Obstructive Pulmonary Disease Patients Combined With Poor Lung Oxygenation.

The ventilation/perfusion mismatch in chronic obstructive pulmonary disease (COPD) patients can exacerbate cardiac function as well as pulmonary oxygenation. We hypothesized that inhaled iloprost can ameliorate pulmonary oxygenation with lung mechanics and myocardial function during one-lung ventilation (OLV) in COPD patients combined with poor lung oxygenation. A total of 40 patients with moderate to severe COPD, who exhibited the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FIO2) <150 mm Hg 30 minutes after initiating OLV, were enrolled in this study. Patients were randomly allocated into either ILO group (n = 20) or Control group (n = 20), in which iloprost (20 μg) and saline were inhaled, respectively. The PaO2/FIO2 ratio, dead space, dynamic compliance, and tissue Doppler imaging with myocardial performance index (MPI) were assessed 30 minutes after initiating OLV (pre-Tx) and 30 minutes after completion of drug inhalation (post-Tx). Repeated variables were analyzed using a linear mixed-model between the groups. At pre-Tx, no differences were observed in measured parameters between the groups. At post-Tx, PaO2/FIO2 ratio (P < .001) and dynamic compliance (P = .023) were significantly higher and dead space ventilation was significantly lower (P = .001) in iloprost group (ILO group) compared to Control group. Left (P = .003) and right ventricular MPIs (P < .001) significantly decreased in ILO group compared to Control group. Inhaled iloprost improved pulmonary oxygenation, lung mechanics, and cardiac function simultaneously during OLV in COPD patients with poor lung oxygenation.

Individualized lung protective ventilation vs. conventional ventilation during general anesthesia in laparoscopic total hysterectomy.

Laparoscopic total hysterectomy is performed by carbon dioxide insufflation, Trendelenburg position and mechanical ventilation of patients under general anesthesia. However, this may induce pulmonary atelectasis and/or hyperdistention of the lungs. Multiple studies have indicated that mechanical ventilation with the use of low tidal volumes, moderate positive end-expiratory pressure (PEEP) and regular alveolar recruitment maneuvers may improve post-operative outcomes. However, the benefits of an individualized level of PEEP have not been clearly established. In the present study, it was hypothesized that a moderate fixed PEEP may not suit all patients and an individually-titrated PEEP during anesthesia may improve the peri-operative pulmonary oxygenation function. The aim of the present study was to compare the pulmonary oxygenation function and post-operative pulmonary complications (PPCs) in patients receiving individualized lung-protective mechanical ventilation (LPV) vs. conventional ventilation (CV) during laparoscopic total hysterectomy. The present study was a randomized double-blinded clinical trial on 87 patients who were randomly divided to receive CV or protective ventilation (PV). An optimal individualized PEEP value was determined using a static pulmonary compliance-directed PEEP titration procedure. Pulmonary oxygenation function, serum inflammatory factors, including interleukin-8 and Clara cell protein 16, the incidence of PPCs and the post-operative length of stay were also determined. Patients in the PV group exhibited improved pulmonary oxygenation function during and after the operation. The total percentage of PPCs during the first 7 days after surgery was significantly lower in the PV group compared with those in the CV group. In conclusion, as compared to CV, intra-operative individualized LPV significantly improved pulmonary oxygenation function and reduced the incidence of PPCs during the first 7 days after laparoscopic total hysterectomy (Clinical trial registration no. ChiCTR1900027738).

Impact of acyclovir use on survival of patients with ventilator-associated pneumonia and high load herpes simplex virus replication

BackgroundHerpes simplex virus (HSV) replication can be detected in the respiratory secretions of a high proportion of ventilated intensive care unit (ICU) patients. However, the clinical significance remains poorly defined. We investigated whether patients with ventilator-associated pneumonia not responding to antibiotics and in whom high levels of HSV could be detected in respiratory secretions benefit from acyclovir treatment.MethodsRespiratory secretions (bronchoalveolar lavage fluid or tracheal aspirates) were tested for HSV replication by quantitative real-time PCR. ICU survival times, clinical parameters, and radiographic findings were retrospectively compared between untreated and acyclovir treated patients with high (> 105 HSV copies/mL) and low (103–105 HSV copies/mL) viral load.ResultsFifty-seven low and 69 high viral load patients were identified. Fewer patients with high viral load responded to antibiotic treatment (12% compared to 40% of low load patients, p = 0.001). Acyclovir improved median ICU survival (8 vs 22 days, p = 0.014) and was associated with a significantly reduced hazard ratio for ICU death (HR = 0.31, 95% CI 0.11–0.92, p = 0.035) in high load patients only. Moreover, circulatory and pulmonary oxygenation function of high load patients improved significantly over the course of acyclovir treatment: mean norepinephrine doses decreased from 0.05 to 0.02 μg/kg body weight/min between days 0 and 6 of treatment (p = 0.049), and median PaO2/FiO2 ratio increased from 187 to 241 between day 3 and day 7 of treatment (p = 0.02). Chest radiographic findings also improved significantly (p < 0.001).ConclusionsIn patients with ventilator-associated pneumonia, antibiotic treatment failure, and high levels of HSV replication, acyclovir treatment was associated with a significantly longer time to death in the ICU and improved circulatory and pulmonary function. This suggests a causative role for HSV in this highly selected group of patients.

Effects of inverse ratio ventilation combined with lung protective ventilation on pulmonary function in patients with severe burns for surgery

ABSTRACT Objective To investigate the effects of inverse ratio ventilation combined with lung-protective ventilation on pulmonary function and inflammatory factors in severe burn patients undergoing surgery. Populations and Methods: Eighty patients with severe burns undergoing elective surgery were divided randomly into two groups: control (CG, n = 40) and experiment (EG, n = 40). The CG had conventional ventilation, whereas the EG were ventilated with tidal volume (TV) of 6–8 ml/kg, I (inspiration): E (expiration) of 2:1, and positive end-expiratory pressure (PEEP) 5 cm H2O. The following variables were evaluated before (T0), 1 h after start of surgery (T1) and after surgery (T2): oxygenation index (OI), partial pressure of carbon dioxide (PaCO2), TV, peak airway pressure (Ppeak), mean airway pressure (Pmean), PEEP, pulmonary dynamic compliance (Cdyn), alveolar–arterial difference of oxygen partial pressure D(A-a)O2, lactic acid (Lac), interleukin (IL)-6 and IL-10, and lung complications. Results: At T1 and T2 time points, the OI, Pmean and Cdyn were significantly greater in the EG than in the CG while the TV, Ppeak, D(A-a)O2, IL-6 and IL-10 were significantly smaller in the EG than in the CG. At the end of the surgery, the Lac was significantly smaller in the EG than in the CG (1.28 ± 0.19 vs. 1.40 ± 0.23 mmol/L). Twenty-four hours after the surgery, significantly more patients had hypoxemia (27.5 vs. 10.0%), increased expectoration (45.0 vs. 22.5%), increased lung texture or exudation (37.5 vs. 17.5%) in the CG than in the EG. Conclusions: Inverse ratio ventilation combined with lung-protective ventilation can reduce Ppeak, increase Pmean and Cdyn, improve the pulmonary oxygenation function, and decrease ILs in severe burn surgery patients.

Effects of Positive End-Expiratory Pressure on Pulmonary Oxygenation and Biventricular Function during One-Lung Ventilation: A Randomized Crossover Study.

Although the application of positive end-expiratory pressure (PEEP) can alter cardiopulmonary physiology during one-lung ventilation (OLV), these changes have not been clearly elucidated. This study assessed the effects of different levels of PEEP on biventricular function, as well as pulmonary oxygenation during OLV. Thirty-six lung cancer patients received one PEEP combination of six sequences, consisting of 0 (PEEP_0), 5 (PEEP_5), and 10 cmH2O (PEEP_10), using a crossover design during OLV. The ratio of arterial oxygen partial pressure to inspired oxygen fraction (P/F ratio), systolic and diastolic echocardiographic parameters were measured at 20 min after the first, second, and third PEEP. P/F ratio at PEEP_5 was significantly higher compared to PEEP_0 (p = 0.014), whereas the P/F ratio at PEEP_10 did not show significant differences compared to PEEP_0 or PEEP_5. Left ventricular ejection fraction (LV EF) and right ventricular fractional area change (RV FAC) at PEEP_10 (EF, p < 0.001; FAC, p = 0.001) were significantly lower compared to PEEP_0 or PEEP_5. RV E/E’ (p = 0.048) and RV myocardial performance index (p < 0.001) at PEEP_10 were significantly higher than those at PEEP_0 or PEEP_5. In conclusion, increasing PEEP to 10 cmH2O decreased biventricular function, especially on RV function, with no further improvement on oxygenation compared to PEEP 5 cmH2O during OLV.

Effect of intraoperative lung-protective mechanical ventilation on pulmonary oxygenation function and postoperative pulmonary complications after laparoscopic radical gastrectomy.

This study aimed to observe the effects of lung-protective ventilation (LPV) on oxygenation index (OI) and postoperative pulmonary complications (PPCs) after laparoscopic radical gastrectomy in middle-aged and elderly patients. A total of 120 patients who were scheduled to undergo laparoscopic radical gastrectomy with an expected time of >3 h were randomly divided into conventional ventilation (CV group) with tidal volume (TV) of 10 mL/kg without positive end-expiratory pressure (PEEP), and lung-protective ventilation (PV group) with 7 mL/kg TV and personal level of PEEP with regular recruitment maneuver every 30 min. Measurements of OI, modified clinical pulmonary infection score (mCPIS), and PPCs were assessed during the perioperative period. Fifty-seven patients in the CV group and 58 in the PV group participated in the data analysis. Patients in the PV group showed better pulmonary dynamic compliance, OI, and peripheral capillary oxygen saturation during and after surgery. The mCPIS was significantly lower in the PV group than in the CV group after surgery. The incidence rate of PPCs was lower in the PV group than in the CV group and the difference was significant in patients whose ventilation time was longer than 6 h in both groups. LPV during laparoscopic radical gastrectomy significantly improved pulmonary oxygenation function and reduced postoperative mCPIS and the incidence of PPCs during the early period after surgery of middle-aged and elderly patients, especially patients whose mechanical ventilation time was longer than 6 h.

ERK1/2/mTOR/Stat3 pathway-mediated autophagy alleviates traumatic brain injury-induced acute lung injury

Acute lung injury (ALI) is one of several complications in patients with traumatic brain injury (TBI). Autophagy is a primary homeostatic process that promotes cell survival under stress. Accumulating evidence implicates autophagy in the pathogenesis of ALI under various conditions. However, the role of autophagy in TBI-induced ALI remains unknown. The aim of this study was to adjust autophagy with pharmacological agents to determine its functional significance in TBI-induced ALI. Rats were preconditioned with autophagy promoter rapamycin or inhibitor 3-methyladenine before they were challenged with TBI. Extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor U0126, mechanistic target of rapamycin (mTOR) inhibitor rapamycin, and signal transducer and activator of transcription 3 (Stat3) inhibitor S31-201 were used to test the role of ERK1/2/mTOR/Stat3 signaling pathway in regulating autophagy. Autophagy is activated in lung tissues after TBI. Enhancement of autophagy suppressed apoptosis, inflammation and oxidative stress in lung tissues, which were activated after TBI, whereas inhibition of autophagy aggravated these critical pathological changes. Autophagy also improved TBI-induced impairment in pulmonary barrier function, oxygenation function and static compliance. Furthermore, TBI-induced autophagy was mediated by ERK1/2/mTOR/Stat3 pathway, which may serve to reduce ALI and improve pulmonary barrier function, oxygenation function and static compliance. These findings are important for the prevention and treatment of TBI-induced ALI.

Effect of early enteral nutrition standardized treatment on blood glucose and prognosis in acute respiratory distress syndrome patients with mechanical ventilation

To study the effect of early entreat nutrition (EN) standardized treatment on optimization of blood glucose control and prognosis in acute respiratory distress syndrome (ARDS) patients with mechanical ventilation (MV). Forty-two patients with MV of ARDS admitted to Huzhou First Municipal People's Hospital from April 2015 to March 2017 were enrolled. April 1st, 2016 was taken as the time node, the patients treated from April 1st, 2015 to March 31st, 2016 were assigned in the control group (n = 20), while the patients treated from April 1st, 2016 to March 31st, 2017 were included in the experimental group (n = 22). The patients in experimental group were given conventional treatment, in 24-48 hours after admission gastrointestinal decompression was stopped and early EN was begun through a nasointestinal tube; the patients in control group received conventional treatment and routine EN (given 48 hours after admission). The differences in nutritional support indexes, the blood glucose variability indexes and the prognostic related indicators were compared between the two groups. Compared with the control group, the initiation time for EN tolerance, first defecation time, time of reaching target feeding amount were significantly earlier in the early EN standardized treatment process management [time of initial EN tolerance (hours): 106.82±42.84 vs. 157.29±56.76, first defecation time (hours): 71.29±23.43 vs. 104.69±26.94, time of reaching target feeding amount (days): 6.24±1.25 vs. 9.86±2.36], the proportions of EN/EN+parenteral nutrition (PN) and the nasointestinal tube feeding reaching the standard on 7 days in experimental group were significantly increased [the proportion of EN/EN+PN: 98.69% vs. 78.69%, the nasointestinal tube feeding reaching standard: 68.18% (15/22) vs. 45.00% (9/20)], average level of blood glucose (GLUave), maximum value of blood glucose (GLUmax), standard deviation of blood glucose (GLUsd), coefficient of variation of blood glucose (GLUcv), hyperglycemia incidence, incidence of multiple organ dysfunction syndrome (MODS), 28-day mortality were significantly decreased [GLUave (mmol/L): 9.4±2.6 vs. 11.5±3.9, GLUmax (mmol/L): 14.19±2.36 vs. 16.26±4.89, GLUsd (mmol/L): 4.86±1.27 vs. 6.87±2.46, GLUcv: (49.86±6.32)% vs. (59.95±5.81)%, hyperglycemia incidence: 59.09% (13/22) vs. 80.00% (16/20), incidence of MODS: 59.09% (13/22) vs. 80.00% (16/20), 28-day mortality: 36.36% (8/22) vs. 45.00% (9/20)], minimum value of blood glucose (GLUmin) was significantly increased (mmol/L: 5.86±2.32 vs. 4.18±1.86), invasive MV time was significantly shorted (hours: 156.82±26.84 vs. 169.93±32.34) with statistically significant differences (all P < 0.05). Early EN could also improve the patient's pulmonary oxygenation function. Since 9 days of disease course, the oxygenation index (PaO2/FiO2) in the experimental group was significantly higher than that of the control group [mmHg (1 mmHg = 0.133 kPa): 256.97±18.63 vs. 239.82±21.72, P = 0.068], but there was no significant difference in the length of ICU stay (days: 13.9±3.6 vs. 14.8±3.4, P > 0.05). The early EN standardized treatment process management can improve the nutritional status, decrease blood sugar fluctuations, and further benefit the improvement of the prognosis of ARDS patients with MV.

Central Hemodynamics and Extravascular Lung Water Index in Varying Degrees of Community-Acquired Pneumonia

Objective : to assess the specific features of central hemodynamics (CH), extravascular lung water index (EVLWI), and pulmonary oxygenizing function in patients with different outcomes of treatment for severe communityacquired pneumonia (CAP). Subjects and methods. The retrospective study enrolled 57 patients with CAP. According to its outcome, there were 2 groups: 1) 44 patients (33 men and 11 women), whose disease ended in recovery; 2) 13 patients (8 men and 5 women), whose CAP resulted in a fatal out come. The groups did not differ in age (48.1±2.3 and 55.3±4.1 years) and overall disease severity according to the APACHE II (21.5±0.8 and 25.2±2.1 scores) and SOFA (8.7±0.2 and 9.7±1.0 scores) scales (p&lt;0.05). CAP was more severe in Group 2: 3.5±0.1 and 4.4±0.27 CURB65 scores (p&gt;0.05). All the patients received identical antibiotic therapy. They underwent transpulmonary thermodilution according to the standard procedure. The indicators were daily recorded. The data were statistically processed. A corre lation analysis was made calculating the correlation coefficients (r). The significance of differences was estimated by the Student's ttest or Mann-Whitney test. Results. On day 1 of followup, the patients in both groups were prone to arterial hypotension, had tachycardia, lower or nearnormal central venous pressure (CVP). Group 1 versus Group 2 had higher cardiac index (CI) (2.9±0.2 and 2.1±0.1 l/min/m2 ) and global ejection fraction (GEF) (22.5±1 and 15.8±1.7%) (p&lt;0.05) and lower CVP (4.1±0.2 and 5.6±0.4 mm Hg) (p&lt;0.05). On day 3, Group 2 versus Group 1 had higher CVP (p&lt;0.05) and lower CI, GEF, and some other cardiac pump function indicators. Admission EVLWI was virtually equally elevated in both groups. In Group 1, the indicator decreased later on and approached the normal values at 67 days of treatment. In Group 2, EVLWI remained high and did not virtually decrease. The indicator was ascertained to be inversely correlated with GEF on treatment days 1—2 (r=0.35 to 0.58; p&lt;0.01) and 6—7 (r=0.67 to 0.43; p&lt;0.001). Conclusion. In the first 24 hours of treatment, the patients with the unfavorable course of severe CAP are diag nosed as having signs of acute respiratory distress syndrome (ARDS) and impaired CH, which can be interpreted as progressive right ventricular dysfunction. The pivotal role of ARDS in the pathogenesis of CH disorders is borne out by the inverse correlation between EVLWI and integral cardiac systolic function indicator and GEF.

Early Use of Surfactant-BL after Lung Transplantation

Goal. To evaluate the clinical effect of early administration of surfactant-BL on pulmonary oxygenizing function and biomechanics in patients early after lung transplantation (LT). Materials and methods. Seven patients early after transplantation were administered with a surfactant-BL («Biosurf», St.-Petersburg, RF) to prevent or treat primary lung transplant disfunction. Results and conclusions. Multiple endobronchial administration of surfactant-BL (0, 24, and 48 hours) resulted in a progressive increase in the ratio of arterial oxygen partial pressure by an average of 94 mm Hg (p&lt;0.05) to oxygen fraction in a respiratory mixture ( РаО2^Ю2) at 48 hours after the surgery and by an average 1.2-fold increase in dynamic thoracopulmonary compliance accompanied by a reduction in the magnitude of PLGD. Employed protocol of surfactant-BL administration was favorable for optimizing the biomechanical properties and oxygenizing function of the lung. The findings clearly demonstrate that the early administration of surfactant-BL after LT should benefit the comprehensive prevention and treatment of PLGD that complicates the early postoperative period after LT.

Effect of NaCl/Hydroxyethyl Starch 200/0.5 on Lung Function and Hemodynamics in Patients Operated on under Extracorporeal Circulation

Objective: to study the effect of 7.2% NaCl/hydroxyethyl starch 200/0.5 on extravascular lung water and respiratory and cardiovascular systems in patients with coronary heart disease (CHD) after myocardial revascularization under extracorporeal circulation (EC). Subjects and methods. A prospective, randomized study was conducted in 40 patients with coronary artery disease. A study group (n=20) received 7.2% NaCl/hydroxyethyl starch 200/0.5; a control group (n=20) had 0.9% NaCl in a dose of 4 ml/kg within 30 min before EC. Extravascular lung water and central hemodynamic parameters were assessed using transpulmonary thermodilution and a Swan-Ganz catheter; respiratory function was estimated by the arterial oxygenation index, alveolar-arterial oxygen tension difference, and venous shunt fraction. Plasma osmolality and Na concentration were determined using an Osmomat 030 device. Conclusion. The intraoperative use of 7.2% NaCl/hydroxyethyl starch 200/0.5 in patients with CHD leads to a significant reduction in extravascular lung water after myocardial revascularization, thereby effectively protecting pulmonary oxygenizing function. The single administration of 7.2% NaCl/hydroxyethyl starch causes a short-term increase in cardiac index and it is a relatively safe in preventing neurological disorders and heart failure. Key words: 7.2% NaCl/hydroxyethyl starch 200/0.5; extravascular lung water, respiratory function, cardiac index, osmolarity.

Oxygen Transport Impairments in Miners with Ischemic Stroke-Induced Comas

Objective: to study oxygen transport impairments in ischemic stroke-induced coma in miners who have been doing underground work for more than 10 years. Subjects and methods. A prospective clinical study was conducted in 48 patients with coma caused by ischemic stroke. Group 1 included 12 miners. Group 2 comprised 36 men not working in coal miners. The groups did not differ in age, disease severity, and admission time. However, the group of miners had a higher incidence of pulmonary complications and therefore higher mortality rates. Comprehensive examination was performed and oxygen delivery index (DO2I), oxygen consumption index (VO2I), oxygen extraction ratio, and arteriovenous oxygen difference were calculated in all those admitted to hospital. Results. In ischemic stroke-induced comas, vasoconstriction resulted in the development of circulatory hypoxia with low DO2I. Then on day 3 respiratory and tissue hypoxia developed in the group of those who had a length of underground service. The relationship between DO2I and VO2I found in the miners suggests that impaired lung oxygenizing function was concurrent with oxygen transport system tension. The fact that there was no significant relationship of the oxygen saturation of hemoglobin in venous blood to VO2I in the miners had a high probability of indicating the development of tissue hypoxia. Such relationships were absent in the patients without underground length of service. Conclusion. The miners with an underground service length of 10 years or more and ischemic stroke-induced comas were found to have rapidly developing, more marked and long-term impairments of central hemodynamics, pulmonary oxygenizing function and hence the oxygen transport system as compared to those with no length of underground service. All the above characteristics are due to the lowered reserve capacities of the cardiovascular irnd respiratory systems upon long-term exposure to poor working conditions. Key words: ischemic stroke, oxygen transport, length of underground service, miner.

Oxygen Transport in Pulmonary Oxygenizing Dysfunction in the Early Periods after Extracorporeal Circulation

Objective: to study the specific features of oxygen transport function in patients with various oxygen delivery changes caused by alveolar opening maneuver (mobilization) performed early after extracorporeal circulation. Subjects and methods. Alveolar opening maneuver was made in the presence of relative arterial hypoxemia under the control of dynamic thora-copulmonary compliance. The maximum airway pressure was as high as 31.1±0.3 cm H2O; the positive end-expiratory pressure was 16.0±0.3 cm H2O. According to the changes in oxygen delivery after alveolar opening maneuver, the investigators retrospectively identified the following groups: 1) (n=14) with a lower and 2) (n=15) higher values. The groups did not differ in age (53.6±2.8 and 56.4±1.8 years), extracorporeal circulation duration (106.4±11.2 and 86.8±4 min), and inotropic support intensity (4.7±0.5 and 4.6±0.6 ^g/kh/min for dopamine and/or dobutamine) (p&gt;0.05). The mode of alveolar opening maneuver and its impact on thoracopulmonary compliance and pulmonary oxygenizing function were identical in the groups (p&gt;0.05). Results. 48.3% of the patients with relative arterial hypoxemia show a linear relationship between the oxygen delivery and consumption indices (r=0.73; p=0.003), and there was a close inverse correlation between the oxygen utilization coefficient and intrapulmonary shunting (r=-0.77; p=0.001). After alveolar opening maneuver, the oxygen delivery index decreased in these cases from 440.7±31.7 to 376.9±20.4 ml/min/m2 (p&lt;0.05). The time course °f changes oxygen delivery influenced mixed venous hemoglobin oxygen saturation (r=-0.71; p=0.005), which was related to lactatemia before (r=0.71; p=0.004) and after (r=0.7; p=0.005) alveolar opening maneuver. Conclusion. After extracorporeal circulation, relative arterial hypoxemia may be concurrent with the signs of oxygen transport system tension in patients with impaired pulmonary oxygenizing function. Moreover, regional blood flow impairments in the peripheral tissues and those in the lung are closely related. After alveolar opening maneuver that improves pulmonary oxygenizing function, oxygen delivery decreases, affecting mixed venous hemoglobin oxygen saturation. The findings give grounds to recommend close monitoring and timely correction during alveolar mobilization in the early period after cardiosurgery. The specific features of oxygen transport and utilization during standard interventions into the heart under extracorporeal circulation call for further in-depth studies. Key words: oxygen transport, oxygen delivery and consumption, alveolar opening maneuver (mobilization), arterial hypoxemia in cardiosurgical patients.

Evaluation of the Efficiency of Alveolar Opening in Cardiosurgical Patients with Low Left Ventricular Ejection Fraction

Objective: to determine the optimum alveolar opening parameters for the improvement of postoperative pulmonary oxygenizing function in patients with a left ventricular ejection fraction (LVEF) of less or more than 40% after aortocoronary bypass surgery (ACBS). Subjects and methods. Twenty patients with a LVEF of less than 40% after ACBS and with postoperative pulmonary oxygenizing dysfunction (PaO2/FiO2 less than 250) (Group 1) were examined. A control group consisted of 20 patients with a LVEF of more than 40% (Group 2). Gas exchange, respiration biomechanics, and central hemodynamic (CH) parameters were monitored (a Vigilance monitor (Edvard LifeScience)). Alveolar mobilization was carried out on Drager Evita-2 apparatuses in the BIPAP mode, by taking into account the previous artificial ventilation (AV) parameters. The low pressure phase corresponded to the positive end-expiratory pressure (PEEP) with volume AV, the high pressure phase was Pplato; the duration of both phases — that of inspiration and expiration (the high pressure phase was inspiration time; the low pressure phase was expiration time). Then the values of Pplato and PEEP were simultaneously increased by 2 cm H2O with a duration of 10 breathing cycles, by continuously monitoring Vt and SaO2 over this interval. By continuously monitoring Vt, a stepwise increase in PEEP and Pplato was continued until there was a Vt reduction or a negative impact of AV on CH. All alveoli were considered to be open when the maximum Vt and SaO2 were achieved. Conclusion. In Group 1 patients with Pinsp of 27—30 cm H2O, PEEP of 10—12 cm H2O, there are increases in PaO2/FiO2 and Cst. In Group 2, the increase of PaO2/FiO2 and Cst is observed with Pinsp of 30—35 cm H2O and PEEP 12—14 cm H2O. With these AV indices, there is an allowable hemodynamic reduction that results in no negative consequences and development of cardiovascular events. After switching to AV in an individually chosen mode, all hemodynamic parameters return to the baseline level. Consequently, the proposed AV mode and ventilation parameters are safe and effective for the prevention of early postoperative respiratory failure in cardiosurgical patients. Key words: recruiting ventilation, positive end-expiratory pressure, alveolar opening.

Correction of Pulmonary Oxygenizing Dysfunction in the Early Activation of Cardiosurgical Patients

Objective: to justify a comprehensive approach to preventing and correcting pulmonary oxygenizing dysfunction requiring prolonged artificial ventilation in patients operated on under extracorporeal circulation for coronary heart disease. Subjects and methods. One hundred and twenty-three patients aged 55±0.6 years were examined. The study excluded patients with a complicated course of operations (perioperative myocardial infarction, acute cardiovascular insufficiency, hemorrhage, and long extracorporeal circulation). Stimulating spirometry was initiated 2 days before surgery. An alveolar opening maneuver was performed using a continuous dynamic thoracopulmonary compliance monitoring. The parameters of lung oxygenizing function and biomechanics were analyzed. Results. In 78% of the patients, preoperative inspiratory lung capacity was 5—30% lower than the age-related normal values. After extracorporeal circulation, pulmonary oxygenizing dysfunction was diagnosed in 40.9% of cases; at the same time PaO2/FiO2 was associated with an intrapulmonary shunt fraction (Qs/St) (r=-0.53; p=0.002) and Qs/Qt was related to static thoracopulmonary compliance (Cst) (r=-0.39; p=0.03). Preoperative stimulating spirometry provided a considerable increase in intraoperative PaO2/FiO2 values (p&lt;0.05); improved Cst and decreased Qs/Qt. After extracorporeal circulation, the incidence of pulmonary oxygenizing dysfunction was decreased by more than twice (p&lt;0.05). Patients with relative arterial hypoxemia showed a noticeable relationship to the magnitudes of a reduction in Cst and a rise in Qs/Qt (r=0.72; p=0.008), which served as the basis for applying the alveolar opening maneuver. This type of lung support corrected arterial hypoxemia in 67% of cases. Conclusion. In car-diosurgical patients with coronary heart disease, effective prophylaxis and correction of relative arterial hypoxemia caused by the interrelated impairments of pulmonary biomechanical properties and ventilation/perfusion ratio may be ensured via preoperative stimulating spirometry and an alveolar opening maneuver early after extracorporeal circulation if indicated. The comprehensive approach allows a reduction in the incidence of pulmonary oxygenizing dysfunction that prevents early activation in the operating suite from 40 to 5—7%. Key words: early activation, pulmonary oxygenizing function, myocardial revascularization, surgery under extracorporeal circulation, tracheal extubation in the operating-room.