Combined Mechanical Ventilation Research Articles

The influence of various technologies for the use of gaseous nitric oxide on the functional and morphological state of the lungs, markers of myocardial damage and clinical outcomes in cardiosurgical interventions with cardiopulmonary bypass

The aim of the study was to evaluate the impact of various technologies for the use of gaseous nitric oxide on the state of the lungs and heart during heart valve surgery under cardiopulmonary bypass (CPB).Methods. The study included 93 patients of both sexes. All patients underwent heart valve surgery and combined surgical interventions under CPB. The patients were divided into 4 groups. Group 1 (control, n = 30) used the standard protocol for anesthetic and perfusion management. Group 2 (n = 30) received inhalation of nitric oxide (20 ppm) within 3 days before surgery, as well as before and after CPB. Group 3 (n = 30) inhaled nitric oxide (40 ppm) throughout surgery with the medication delivered through inspiratory part of the ventilator and combined with perfusion of the pulmonary artery and reduced volume ventilation during CPB. Group 4 (n = 33) received nitric oxide (40 ppm) via oxygenator of the heart-lung machine. We assessed changes in the functional parameters of the lungs at different phases of surgery, performed a morphological examination of the lungs in the initial phase (before CPB), at the peak of ischemia, and after reperfusion. The state of the myocardium after surgery was assessed by troponin I (cTnI) activity at the beginning of the operation, after transfer to the ICU, at 12, 24 and 48 hours after the surgery. Myocardial damage index (MDI) was calculated according to the following formula: MDI = TnIlate / TnIearly. The clinical outcomes of the surgeries were evaluated.Results. There were no statistically significant differences in the functional state of the lungs with various options for inhalation delivery and administration via the CPB circuit. The most intact indicators of the functional state of the lungs were seen in patients of Group 3 who received inhaled nitric oxide throughout surgery and combined mechanical ventilation with the addition of nitric oxide and perfusion of the pulmonary artery during CPB. Morphological examination of the lungs showed that inhalation of nitric oxide before CPB does not prevent the development of morphological disorders. Morphological changes found in Group 3 were the smallest. The supply of nitric oxide into the CPB circuit statistically significantly improved the restoration of pulmonary blood flow during reperfusion. The cTnI level statistically significantly increased in all groups of patients, however, it was statistically significantly lower in Groups 2, 3, and 4 compared with Group 1 at the end of surgery, in Groups 3 and 4 compared with Groups 1 and 2 after 12 and 24 hours, and in Group 3 after 48 hours. The most favorable changes in the MDI were seen in Group 3; statistically significantly lower MDI was registered 12 and 48 hours after surgery in this group compared with Groups 1, 2, and 4. A lower complication rate, a shorter duration of ventilation and stay in the ICU were observed in Groups 3 and 4.Conclusion. Nitric oxide has a protective effect on the lungs and heart when used during anesthesia and cardiopulmonary bypass in heart valve surgery. It preserves the lung function and morphology and statistically significantly reduces cTnI level and myocardial damage index in the postoperative period. The extent of the protective effect depends on the nitric oxide exposure time and is most pronounced when nitric oxide is used throughout the surgery, including during CPB.

Frequency of typical complications of morphine during its intrathecal and epidural introduction in knee arthroplasty

The objective was to compare the efficacy and safety of morphine in neuraxial blocks during knee arthroplasty.Materials and methods. A retrospective analysis of 60 medical histories of patients who underwent total knee arthroplasty for the period from 2017 to 2019 was performed. All patients were operated under general anesthesia with mechanical ventilation in combination with epidural or spinal analgesia with opiates. Patients of the 1st group (n=20) after catheterization of the epidural space at the level of L1–2 were injected with a morphine solution 1% – 0.3 ml epidurally. Patients of the 2nd group (n=20) were injected with a morphine solution 1% – 0.01 ml intrathecally at the level of L3–4. Patients of the 3rd group (n=20) underwent standard combined anesthesia: general anesthesia with mechanical ventilation and epidural analgesia at the level of L1–2 with a solution of 0.2% ropivacaine in the form of an infusion of 6 ml/hour. All patients received infusion of 0.2% solution of ropivacaine epidurally 6 ml/hour at the level of L1–2 in the postoperative period.The incidence of nausea, vomiting, pruritus, headache and the level of postoperative pain syndrome were assessed on a numerical rating scale 6 hours after the end of the surgery.Results. The level of pain syndrome in patients who received intrathecal and epidural analgesia with morphine was equally low, while in patients who received epidural analgesia with ropivacaine, the level of pain syndrome was statistically significantly higher, which required the additional prescription of non-steroidal anti-inflammatory drugs and/or narcotic analgesics parenterally. The frequency of nausea, vomiting, pruritus and headaches was maximum in the 2nd group, significantly lower in the 1st, while in the 3rd, pruritus did not occur.Conclusion. The use of morphine in neuraxial block in knee arthroplasty has a positive effect on the quality of anesthesia and postoperative pain relief.

Efficacy of High-Dose Vitamin C Infusion on Outcomes in Sepsis Requiring Mechanical Ventilation: A Double-Blind Randomized Controlled Trial.

Background Critically ill patients have an increased requirement for vitamin C in sepsis and these patients have low levels of vitamin C. The researchers validated the efficacy of high-dose vitamin C intravenous infusion (IVI) in patients with sepsis requiring mechanical ventilation. Methods Forty patients were randomly assigned to 2 groups (20 each) in a 1 : 1 ratio in accordance with the vitamin C treatment regimen: Group I (GI): patients received 1.5 g/6 h vitamin C in 50 ml of dextrose 5% in water (D5W) IVI over 30 minutes for 4 consecutive days; Group II (GII): patients received 100 mg vitamin C/day as a first single dose in 50 ml of D5W IVI over 30 minutes and the other three subsequent doses were 50 ml of plain D5W IVI over 30 minutes for 4 consecutive days. Primary outcomes were the change in sequential organ failure assessment (SOFA) score at day 7, the incidence of ventilator-associated pneumonia (VAP), and the plasma vitamin C level. The glutathione peroxidase (GPX) activity, C-reactive protein (CRP) level, duration of vasopressor therapy, and 28-day mortality were secondary outcomes. Results The change in SOFA score at day 7 showed a significant difference between GI and GII (p < 0.001). The incidence of early VAP was significantly lower in GI (p=0.044). Vitamin C levels showed a significant rise in GI at day 1 and day 4 (p < 0.001 and p < 0.001, respectively). GPX activity of day 4 and day 7 was significantly higher in GI (p=0.005 and p=0.014, respectively). CRP levels of day 4 and day 7 were significantly higher in GII (p < 0.001 and p < 0.001, respectively). There was a significant difference in 28-day mortality (p=0.038) and duration of vasopressor therapy (p=0.033) in GI compared to GII. Conclusion The early use of high-dose vitamin C intravenous infusion in patients with sepsis requiring mechanical ventilation in combination with the standard treatment for sepsis lowered the incidence of VAP, increased the antioxidant status, and improved the illness severity. Trial Registration. This trial is registered with ClinicalTrials.gov Identifier (NCT04029675).

Refined acquisition of high-resolution chest CTs in macaques by free breathing.

The use of medical imaging as a non-invasive or minimally invasive method to assess disease or treatment response continues to grow. A similar trend is observed in pre-clinical research, in general, and more specifically in macaques, enabling longitudinal assessment of disease in individual animals. Computed tomography (CT) is such an imaging technique used to obtain clinically applicable data. To acquire a chest CT using a cone beam tomography system, some kind of respiration control is needed. A commonly used technique for this is endotracheal intubation and mechanical ventilation. However, although routinely performed this can increase the risk of impact on welfare in comparison with non-invasive imaging. Therefore, we studied the option of retrospectively gated CTs: acquiring high resolution chest CTs in freely breathing macaques. For this, we compared 748 CTs obtained during free breathing with 881 CTs obtained with mechanical ventilation in combination with a breath-hold procedure predominantly on the appearance of misregistration artifacts. The scans were obtained during different stages of multiple experimentally induced respiratory diseases. The comparison shows that although there are still streaking artifacts present in the retrospective gated scans, the amount of shading artifacts is reduced to such a level that it possibly dominates underlying lesions, causing misdiagnosis. Our data reveal that the use of retrospective gating in high resolution CTs for macaques can be successfully applied. With the use of this technique, artifacts due to free breathing are reduced to a diagnostically appropriate level. Most importantly, this technique makes chest CTs with this instrumentation a non-invasive modality.

Patients with acute respiratory distress syndrome due to pandemic Coronavirus disease 2019 (COVID-19)

We report on a case study of patients with Coronavirus disease 2019 (COVID-19). Evaluation of factors predicting outcome in patients with COVID-19 are very important. Both patients developed respiratory failure complicated by acute respiratory distress syndrome. Patients were intubated and invasively ventilated, underwent prone positioning and careful ventilation according to criteria for acute respiratory distress syndrome. In addition, biomarkers were daily evaluated including C-reactive protein, d-dimer and high-sensitive troponin T. Although treatment did not differ between patients, one patient survived whereas the other one died. The patient who survived had a faster onset of invasive ventilation with prone positioning, a lower maximal level of C-reactive protein and a lower value of high-sensitive troponin T. The use of mechanical ventilation in combination with a high PEEP and an early start of prone positioning in patients with severe ARDS may be beneficial. The values of C-reactive protein and troponin T levels seems to be predictive for the clinical course. Keywords: Coronavirus disease 2019; COVID-19; Troponin; C-reactive protein; Mechanical ventilation.

Predictive Factors and Safety of Noninvasive Mechanical Ventilation in Combination With Propofol Deep Sedation in Left Atrial Ablation Procedures

Catheter ablation is nowadays the core treatment of atrial fibrillation (AF). Propofol infusion sedation is an accepted safety strategy; however, respiratory depression with respiratory variations is frequent. Noninvasive mechanical ventilation (NIV) added to deep sedation could improve procedural safety and success. We sought to assess the predictive factors and safety of NIV in combination to propofol deep sedation in left atrial ablation procedures. Procedural data from 252 consecutive patients who underwent left atrial ablation (166 [66%] persistent, 86 [34%] for paroxysmal AF) were analyzed. Sedation with 1% propofol was used in all procedures and controlled by electrophysiologists. Arterial blood gas analysis was performed regularly during the procedure. NIV was indicated for respiratory depression with pH <7.25 and pCO2 >50 mm Hg or agitated patient with the need for more profound sedation. No patient needed endotracheal intubation, and no procedure was abandoned due to adverse effects of sedation. NIV was used in 25 patients (10%). Predictive factors for the use of NIV were high-dose propofol sedation (p = 0.010), persistent AF (p = 0.029), prolonged procedure time (p = 0.006), increased body mass index (p = 0.008) and presence of obstructive sleep apnea (OSA; p <0.001). In a Cox regression analysis, OSA was an independent factor for NIV use (p = 0.016). In conclusion, propofol deep sedation for patients who underwent left atrial ablation is safe. Adding NIV in high-risk patients (i.e., OSA, high body mass index, and lengthy procedure duration) provides better respiratory homeostasis and could impact long-term procedure results.

P5748Predictive factors and safety of non invasive mechanical ventilation in combination to Propofol deep sedation in left atrial ablation procedures

P5748Predictive factors and safety of non invasive mechanical ventilation in combination to Propofol deep sedation in left atrial ablation procedures

Different ventilation modes combined with ambroxol in the treatment of respiratory distress syndrome in premature infants.

The aim of the present study was to compare the effectiveness of different modes of mechanical ventilation in combination with secretolytic therapy with ambroxol in premature infants with respiratory distress syndrome. Seventy-three premature infants with hyaline membrane disease (HMD) (stage III–IV), also known as respiratory distress syndrome, who were supported by mechanical ventilation in the neonatal intensive care unit (NICU) of Xuzhou Central Hospital, were involved in the present study, between January 2013 and February 2015. Forty cases were randomly selected and treated with high frequency oscillatory ventilation (HFOV), forming the HFOV group, whereas 33 cases were selected and treated with conventional mechanical ventilation (CMV), forming the CMV group. Patients in the two groups were administered ambroxol intravenously at a dosage rate of 30 mg/kg body weight at the beginning of the study. The present study involved monitoring the blood gas index as well as changes in the respiratory function index in the two groups. Additionally, the incidence of complications in the premature infants in the two groups was observed prior to and following the ventilation. Pulmonary arterial oxygen tension (PaO2), the PaO2/fraction of inspired oxygen (FiO2) ratio, the oxygenation index [OI = 100 × mean airway pressure (MAP) × FiO2/PaO2], as well as the arterial/alveolar oxygen partial pressure ratio (a/APO2) = PaO2/(713 × FiO2 partial pressure of carbon dioxide (PaCO2)/0.8) of the patients in the HFOV group after 1, 12 and 24 h of treatment were significantly improved as compared to the patients of the CMV group. However, there was no significant difference between patients in the two groups with regard to the number of mortalities, complications such as pneumothorax, bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), and the time of ventilation. In conclusion, combining HFOV with ambroxol secretolytic therapy is a more viable option, as the combined treatment resulted in significant improvements in arterial blood gas levels, oxygenation and the respiratory function of lungs in preterm infants.

Effect of nephroprotection therapy on kidney function at resection

The aim – to compare two prevention methods of nephrosclerosis after resection of the kidney. Material and methods. In group 1 were included 83 patients in whom the kidney were resected during surgery was used general anesthesia and mechanical ventilation, in group 2–23 patients in whom anesthesia was used for general anesthesia with mechanical ventilation in combination with prolonged epidural analgesia. Patients in both groups received perioperative period nephroprotective therapy which included the administering two days before surgery enalapril 5 mg once a day, which continued to take in postoperative period, followed in such doses within one year after the surgery, intraoperative pentoxifylline administration of 5 ml, followed by administration of 5 ml twice per day for three days. Monitoring of blood pressure, glomerular filtration rate and β2-microglobulin in plasma. Results. It was found that using both methods nephroprotection no effect on hemodynamic parameters. The volume of blood loss was significantly lower when using an epidural. Glomerular filtration rate in group 1 was lower at the end of the 7th day when compared with group 2, although not statistically significant. The content of β2-microglobulin in plasma significantly increased compared with preoperative values and continued to be kept in such figers at 3, 6 and 12 months follow-up. Although fluctuations of content β2-microglobulin in plasma were statistically significant they do not exceed the reference values. Comparing group 1 and group 2 on stage study st atistically significant changes were set at 6 and 12 months postoperative. The content of β2-microgl obulin in plasma was higher in group 1.Conclusions. The use nephroprotective therapy does not cause significant hemodynamic fluctuations, safe kidney function. Determination of β2-microglobulin in plasma is a valuable method for early diagnosis of renal impairment.

Variability of In Vivo Fluid Dose Distribution in Mouse Airways Is Visualized by High-Speed Synchrotron X-Ray Imaging

The manner in which fluid instillations into mouse nose and lung distribute through the airways is poorly understood. Many agents are delivered in this way for testing as therapeutics, or as challenges designed to establish infections or create systemic drug delivery effects. These agents are delivered into mouse airways with little knowledge of the manner in which doses move through the airways, how long they reside in each region, and where the instilled materials eventually reach. Synchrotron phase-contrast X-ray imaging (PCXI) was used to elucidate the primary controlling characteristics of mouse airway fluid dosing. High-speed image acquisition was used to track the movement of a range of bolus doses of an iodine-based contrast fluid through the nose (n=15) and lungs (n=10) of live anesthetized mice. For the lung studies, the mice were ventilated and paralyzed to control animal movement. Post-experiment image processing was used to visualize the fluid movement. The maximum dose that could be retained in only the anterior nose was ∼7.5 μL (20 g mouse), and a range of dynamic dose behaviors was documented after delivery. In the lung, the use of mechanical ventilation in combination with a paralytic agent prevented confounding artifactual movement, improving visualization of fluid progression through the airways. In the lung, optimized image analysis using the high image capture rate revealed the presence of respiratory pauses that could not be visualized at slower acquisition rates. The variability in the outcome of identical dose deliveries in different animals indicates that uniform lung distribution cannot be expected to occur with tracheal fluid delivery. With adequate imaging rate and fluid dose parameters, this study shows the utility of synchrotron PCXI for determining the post-delivery behavior and fate of fluid doses such as those used in in vivo gene transfer or pharmaceutical studies.

Effect of positive end-expiratory pressure on the pressure gradient of venous return in hypovolemic patients under mechanical ventilation

To assess the effects of positive end-expiratory pressure (PEEP) on central venous pressure (CVP) and common iliac venous pressure (CIVP), and the difference between CVP and CIVP [D(c-i)VP] in hypovolemic patients under mechanical ventilation. From May 2007 to May 2009, 30 acute hypovolemic adult patients undergoing mechanical ventilation in intensive care unit (ICU) were enrolled. The patients were randomly divided into three groups, and PEEP with 0, 5, 10 cm H(2)O (1 cm H(2)O=0.098 kPa) levels were used respectively. Ten mechanically ventilated patients with similar basic clinical conditions but normal blood volume were selected randomly as the control group. CVP, CIVP and D(c-i)VP were measured and recorded at each PEEP level in both groups. The patients' heart rate, mean artery pressure and respiratory pressure data were also collected. The correlation analysis was used to analyze relationship between CVP and CIVP and between the changes in venous pressure and the changes in respiratory pressure. (1)CVP increased significantly when PEEP level was elevated in the study group. When PEEP was 0, 5 and 10 cm H(2)O, the CVP was (1.3+/-0.9), (3.1+/-1.3) and (4.5+/-1.3) mm Hg, respectively (1 mm Hg=0.133 kPa, all P<0.01). Whereas, in the control group, the changes in CVP was small. At 0, 5 and 10 cm H(2)O PEEP levels, CVP was (6.9+/-1.3), (7.2+/-1.2) and (8.0+/-1.5) mm Hg, respectively, but when CVP at PEEP0 and PEEP5 was compared with that of PEEP10, the difference was significant (P<0.01 and P<0.05). There was slight increase of CIVP in both groups when PEEP was elevated. D(c-i)VP was increased significantly in the study group compared with control group (all P<0.01). But the value was gradually decreased when with elevation of PEEP. When PEEP level was elevated from 0 to 10 cm H(2)O, D(c-i)VP value was lowered from (4.9+/-1.7) mm Hg to (2.8+/-1.4) mm Hg. No significant difference in D(c-i)VP was found in the control group. The D(c-i)VP values in the control group were equal or lower than 1.5 mm Hg at three PEEP levels. (2)No relationship was found between CVP and CIVP at each PEEP level in the study group (r(1)=0.236, r(2)=0.299, r(3)=0.262, all P>0.05), but there was a statistically significant correlation between CVP and CIVP in the control group (r(1)=0.485, r(2)=0.679, r(3)=0.748, all P<0.05). The findings suggest that it may not be appropriate to use CVP or CIVP to evaluate the patients' blood volume and effect of volume resuscitation in the hypovolemic patients undergoing mechanical ventilation in combination with PEEP.

Analysis on reasons of patients undergone long-term mechanical ventilation in combination with airway granuloma and countermeasures

Objective To explore the reasons of patients undergone long-term mechanical ventilation in combination with airway granuloma and the nursing countermeasures. Methods The information of 15 eases undergone long-term mechanical ventilation in combination with airway granuloma in department of geriatric and respiratory were summarized and analyzed. Results The occurrence of airway granuloma was strictly related to local stimulation, nutrient deficiency and incision model. Condnsions The basic nursing should be strengthened agaisnt the above reasons, thereby reducing and avieding the occurrence of airway granuloma. The nursing measures adopted when the airway granuloma occurs also should be strengthened. Key words: Ventilation, mechanical; Granulma, respiratory tract; Nursing care

Evaluation of lung function after intratracheal perfluorocarbon administration in healthy animals.

To investigate the effects of partial liquid ventilation (i.e., mechanical ventilation in combination with intratracheal administration of perfluorocarbon) on lung function, with particular attention to the integrity of the alveolocapillary membrane in healthy adult animals. Prospective, randomized, controlled study. Laboratory at the Department of Experimental Anesthesiology, Erasmus University Rotterdam. Ten adult male New Zealand rabbits. Five rabbits were intratracheally treated with 12 mL/kg of perfluorocarbon while conventional mechanical ventilation (volume-controlled, tidal volume of 12 mL/kg, respiratory rate of 30 breaths/min, inspiration/expiration ratio of 1:2, positive end-expiratory pressure of 2 cm H2O, and an FIO2 of 1.0) was applied for 3 hrs. To assess the permeability of the alveolocapillary membrane, pulmonary clearance of inhaled technetium-99m-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA) measurements were performed at 3 hrs and compared with data from the control group (n = 5) treated with mechanical ventilation only, using the same ventilatory parameters. Pulmonary gas exchange and lung mechanical parameters were measured in both groups at 30-min intervals. Mean values for PaO2 in the perfluorocarbon group, although at adequate levels, were less than those values of the control group during the 3-hr study period (370 +/- 44 vs. 503 +/- 44 torr at 3 hrs [49.3 +/- 5.9 vs. 67.1 +/- 5.9 kPa]). Peak and mean airway pressures were higher in the perfluorocarbon group (ranging from 1.9 to 3.4 cm H2O and 0.7 to 1.3 cm H2O, respectively) compared with the control group, while end-inspiratory airway pressure was similar in both groups. The half-life of 99mTc-DTPA was 83.7 +/- 24.5 mins in the control group, which was significantly longer (p < .01) than in the perfluorocarbon group (49.8 +/- 6.1 mins). These findings suggest that partial liquid ventilation with perfluorocarbons lowers pulmonary gas exchange in healthy animals, and the increased pulmonary clearance of 99mTc-DTPA after 3 hrs of this type of ventilatory support may reflect minimal reversible changes in the lung surfactant system.

Intratracheal Perfluorocarbon Administration as an Aid in the Ventilatory Management of Respiratory Distress Syndrome

Respiratory distress syndrome carries a high morbidity and mortality when treated with mechanical ventilation with positive end-expiratory pressure. Perfluorocarbon liquids are employed in liquid ventilation due to low surface tension and high gas solubility. To assess whether intratracheal administration of the perfluorocarbon, perflubron, in combination with conventional mechanical ventilation could be of therapeutic benefit in respiratory distress syndrome, the authors tested the effects of different doses of intratracheal perflubron administration on gas exchange and lung mechanics in adult animals with respiratory failure during a 6-h observation period. Respiratory failure was induced in 30 rabbits by saline lung lavage (arterial oxygen tension < 100 mmHg at 100% oxygen with the following ventilator settings: tidal volume, 12 ml.kg-1; respiratory frequency, 30 per min; inspiratory/expiratory ratio, 1:2; and positive end-expiratory pressure of 6 cm H2O). Twenty-four rabbits were treated with different perfluorocarbon doses (3, 6, 9, and 12 ml.kg-1), and the remaining six served as controls while mechanical ventilation was continued with the aforementioned settings. Additionally, in ten healthy rabbits who were used as healthy controls, the lungs were mechanically ventilated either alone or in combination with intratracheal perfluorocarbon administration (3 ml.kg-1) for 6 h. In all treatment groups, arterial oxygen pressure increased significantly (P < 0.0001) in a dose-related fashion (193 +/- 40, 320 +/- 70, 353 +/- 125, and 410 +/- 45 mmHg at 15 min), and peak airway pressures decreased significantly (range, 18-23%; P < 0.0001) from pretreatment values. These findings were in contrast to those for the control group. The improvements were time-dependent in all four tested perfluorocarbon doses. However, the improvements in pulmonary parameters could be extended to 6 h only in groups treated with 9 ml.kg-1 and 12 ml.kg-1 perflubron. At the end of the 6-h period, the data for these two groups showed significantly higher arterial oxygen pressure (230 +/- 84 and 197 +/- 130 mmHg, respectively; P < 0.05) and lower inflation pressures than the pretreatment data for these groups and the data for the control group at 6 h. There were no clinically significant changes in pulmonary parameters in healthy animals due either to mechanical ventilation alone or mechanical ventilation in combination with intratracheal perfluorocarbon administration for 6 h. The results of this study imply that there is no association between the lung mechanics and gas exchange parameters for mechanical ventilation in combination with intratracheal perfluorocarbon administration. The data suggest that this type of perfluorocarbon administration with conventional mechanical ventilation offers a simple, alternative treatment of respiratory distress syndrome. With this technique, adequate pulmonary gas exchange can be maintained at relatively low airway pressures with high perfluorocarbon doses for several hours.