Adequate Gas Exchange Research Articles

Design and Implementation of a Computer-Controlled Hybrid Oscillatory Ventilator.

During mechanical ventilation, lung function and gas exchange in structurally heterogeneous lungs may be improved when volume oscillations at the airway opening are applied at multiple frequencies simultaneously, a technique referred to as multifrequency oscillatory ventilation (MFOV). This is in contrast to conventional high-frequency oscillatory ventilation (HFOV), for which oscillatory volumes are applied at a single frequency. In the present study, as a means of fully realizing the potential of MFOV, we designed and tested a computer-controlled hybrid oscillatory ventilator capable of generating the flows, tidal volumes, and airway pressures required for MFOV, HFOV, conventional mechanical ventilation (CMV), as well as oscillometric measurements of respiratory impedance. The device employs an iterative spectral feedback controller to generate a wide range of oscillatory waveforms. The performance of the device meets that of commercial mechanical ventilators in volume-controlled mode. Oscillatory modes of ventilation also meet design specifications in a mechanical test lung, over frequencies from 4 to 20 Hz and mean airway pressure from 5 to 30 cmH2O. In proof-of-concept experiments, the oscillatory ventilator maintained adequate gas exchange in a porcine model of acute lung injury, using combinations of conventional and oscillatory ventilation modalities. In summary, our novel device is capable of generating a wide range of conventional and oscillatory ventilation waveforms with potential to enhance gas exchange, while simultaneously providing less injurious ventilation.

Veno-venous extracorporeal membrane oxygenation-assisted treatment of severe airway stenosis due to goiter: Two case reports.

Extracorporeal membrane oxygenation (ECMO) is a critical care intervention that acts as a temporary substitute for the heart and lungs, facilitating adequate tissue perfusion and gas exchange. The 2 primary configurations, veno-arterial and veno-venous ECMO, are tailored to support either the heart and lungs or the lungs alone, respectively. The case report details patients with tumor-induced airway stenosis who encountered limitations with standard treatments, which were either insufficient or carried the risk of severe complications such as hypoxia and asphyxia. Patients were diagnosed with severe airway stenosis caused by goiter, a condition that required innovative treatment approaches to prevent complications during the management process. Veno-venous ECMO was implemented as a bridging therapy to provide vital respiratory support during the tumor resection procedure. This intervention was crucial in reducing the risks associated with airway edema or tumor rupture. With the use of veno-venous ECMO, the patients successfully underwent tumor resection. They were subsequently weaned off the ECMO support, and after a course of treatment, they were discharged in good condition. The case demonstrates the efficacy of veno-venous ECMO as a bridging therapy for managing severe airway stenosis caused by goiter. Its use facilitated the successful resection of tumors and led to positive patient outcomes, highlighting its potential as a valuable treatment option in similar scenarios.

Pulmonary Shunt in Critical Care: A Comprehensive Review of Pathophysiology, Diagnosis, and Management Strategies.

Pulmonary shunt, an abnormal passage of blood through the pulmonary circulation without adequate gas exchange, poses significant challenges in critical care. This comprehensive review explores the pathophysiology, diagnostic approaches, and management strategies associated with pulmonary shunt. Pulmonary shunts are classified into anatomical and physiological types, each with distinct mechanisms and implications for gas exchange. Anatomical shunts result from structural heart defects, while physiological shunts arise from ventilation-perfusion (V/Q) mismatches. Both conditions can significantly impair oxygenation and contribute to multi-organ dysfunction. This review delves into various diagnostic modalities, including clinical assessment, imaging techniques such as chest X-ray and CT scans, and advanced diagnostic methods such as V/Q scanning and echocardiography. Challenges in diagnosing pulmonary shunt are discussed, emphasizing the limitations of current tools and the need for accurate differentiation of shunt types. Management strategies are examined, covering pharmacological interventions, non-pharmacological treatments such as mechanical ventilation and prone positioning, and surgical options. Emerging therapies and innovations in treatment are also highlighted. Special considerations are given to different patient populations, including pediatric and elderly patients and those with multiple comorbidities. This review concludes with an analysis of the prognosis and outcomes associated with pulmonary shunt, focusing on short-term and long-term impacts on survival and quality of life. This review aims to enhance understanding and guide effective management practices for pulmonary shunt in critical care settings by synthesizing current knowledge and identifying areas for further research.

Acute Respiratory Failure: Pathophysiology, Diagnosis, and Current Therapeutic Modalities

Acute respiratory failure (ARF) represents a critical condition wherein the respiratory system fails to maintain adequate gas exchange, leading to hypoxemia, hypercapnia, or both. The etiology of ARF is multifactorial, encompassing a wide array of pulmonary and extrapulmonary disorders. Prompt diagnosis and intervention are paramount to improving patient outcomes. This article provides a comprehensive review of the pathophysiology underlying ARF, diagnostic approaches, and the latest advancements in therapeutic strategies. We explore both invasive and non-invasive treatment modalities, including mechanical ventilation, extracorporeal membrane oxygenation (ECMO), pharmacotherapy, and supportive care measures. By integrating recent clinical evidence, we aim to elucidate the evolving landscape of ARF management, highlighting best practices and emerging innovations in the field.

Indications and Short-Term Outcomes of Conventional Mechanical Ventilation in a Neonatal Intensive Care Unit of a Tertiary Care Hospital in a Developing Country

Background: Mechanical ventilation is an advanced intervention employed in neonatal intensive care units (NICUs) to assist neonates who require external ventilation for adequate gas exchange, while minimizing associated complications. Understanding the indications and short-term outcomes of mechanical ventilation is crucial for improving neonatal care, especially in developing countries with limited resources. Objective: To examine the indications and short-term outcomes of conventional mechanical ventilation in a neonatal intensive care unit of a tertiary care hospital in a developing country. Methods: This descriptive cross-sectional study was conducted from July 2022 to February 2023 in the Department of Paediatrics at Combined Military Hospital, Kharian. The study included 227 pediatric patients admitted to the NICU for mechanical ventilation, selected via consecutive non-probability sampling. Written informed consent was obtained from parents or guardians. Data collected included neonatal and pregnancy parameters, primary indication for mechanical ventilation, duration of mechanical ventilation, and length of hospital stay. Patients were monitored for complications such as pneumothorax, sepsis, and ventilator-associated pneumonia. Statistical analysis was performed using IBM SPSS Statistics for Windows, version 26.0. Quantitative variables were expressed as mean ± standard deviation or median and interquartile range, while qualitative variables were presented as frequencies and percentages. Comparisons were made using the Chi-square test, Fisher's exact test, independent samples t-test, or Mann-Whitney U test as appropriate, with a p-value of ≤0.05 considered significant. Results: The study included 128 males (56.4%) and 99 females (43.6%). The mean gestational age at birth was 36.4 ± 1.5 weeks, and the mean birth weight was 2994.1 ± 450.1 grams. Common indications for mechanical ventilation included pneumonia (26.4%), respiratory distress syndrome (24.7%), and sepsis (18.5%). The mean duration of mechanical ventilation was 7.1 ± 2.5 days, and the mean length of hospital stay was 13.4 ± 6.0 days. Complications were observed in 29.5% of patients, with ventilator-associated pneumonia (18.1%) being the most common, followed by sepsis (9.7%) and pneumothorax (5.3%). The overall mortality rate was 18.5%. Significant associations were found between mortality and duration of mechanical ventilation (p<0.001), occurrence of complications (p<0.001), and requirement for re-intubation (p<0.001). Conclusion: The study highlights the significant association between prolonged mechanical ventilation, the development of complications, and increased mortality in neonates. Effective strategies to prevent and manage complications, as well as to limit the duration of mechanical ventilation, are essential to improve neonatal outcomes in resource-limited settings.

The development and implementation of a low-cost mechanical ventilator in a low-middle-income country during the COVID-19 pandemic: The Unisabana-HERONS

BackgroundThe COVID-19 pandemic in Latin America generated the need to develop low-cost, fast-manufacturing mechanical ventilators. The Universidad de La Sabana and the Fundacion Neumologica Colombiana designed and manufactured the Unisabana-HERONS (USH) ventilator. Here, we present the preclinical and clinical study results to evaluate its effectiveness and safety characteristics in an animal model (Yorkshire Sow) and five patients with acute respiratory failure receiving mechanical ventilatory support for 24 h. MethodsThe effectiveness and safety outcomes included maintaining arterial blood gases and pulse oximetry saturation (SpO2), respiratory pressures and volumes (during continuous monitoring) in the range of ARDS and lung-protective strategy goals, and the occurrence of barotrauma. A significance level of 0.05 was used for statistical tests. This clinical trial was registered on Clinicaltrials.gov (NCT04497623) and approved by the ethics committee. ResultsAmong patients treated with the Unisabana-HERONS, the most frequent causes of acute respiratory failure were pneumonia in 3/5 (60 %) and ARDS in 2/5 (40 %). During the treatment, the ventilatory parameters related to lung protection protocols were kept within the safety range, and vital signs and blood gas were stable. The percentage of time that the respiratory pressures or volumes were out of safety range were plateau pressure >30 cm H2O: 0.00 %; driving pressure >15 cm H2O: 0.06 %; mechanical power >15 J/min: 0.00 %; and Tidal volume >8 mL/kg: 0.00 %. There were no adverse events related to the ventilator. The usability questionnaire retrieved a median score for all items between 9 and 10 (best score: 10), indicating great ease of use. ConclusionThe Unisabana-HERONS ventilator effectively provided adequate gas exchange and maintained the ventilatory parameters in the range of lung protection strategies in humans and an animal model. Furthermore, it is straightforward to use and is a low-cost medical device.

Apneustic anesthesia ventilation improves pulmonary function in anesthetized bottlenose dolphins (Tursiops truncatus).

Use of mechanical ventilation during general anesthesia is a necessary practice in the anesthetization of small cetaceans as spontaneous ventilation fails to provide adequate gas exchange. Currently available methods of ventilation do not account for the intermittent breathing strategy of representative species within this infraorder of fully aquatic mammals and may have a significant effect on cardiac and respiratory physiology. To understand the impact of mechanical ventilation on cardiopulmonary function in one small species of cetacean, the bottlenose dolphin (Tursiops truncatus), we compared controlled mechanical ventilation (CMV) to a novel ventilation method known as apneustic anesthesia ventilation (AAV). AAV simulates the normal inspiratory breath-hold pattern of dolphins. Ten anesthetic procedures (dental procedure, n = 9; bronchoscopy, n = 2) were performed on nine dolphins (age range: 10-42 years; mean = 32 years; median = 37 years; female = 3, 40%; male = 6, 60%). In a cross-over study design, dolphins were instrumented and randomly assigned to AAV or CMV as the initial mode of ventilation, then switched to the alternate mode. Baseline cardiopulmonary data were collected and again after 30 min on each mode of ventilation. Cardiac index, stroke volume index, systemic vascular resistance, alveolar dead space, alveolar-arterial oxygen tension gradient, arterial oxygen content, oxygen delivery index, and dynamic respiratory system compliance index were calculated at each of the four time points. During AAV, dolphins had higher arterial oxygen tension, higher mean airway pressure, reduced alveolar dead space ventilation and lower alveolar-arterial oxygen difference. Cardiovascular performance was not statistically different between the two modes. Our study suggests AAV, which more closely resembles the conscious intermittent respiratory pattern phenotype of dolphins, improves ventilation and pulmonary function in the anesthetized dolphin. Future studies should evaluate the cardiopulmonary effects of neutral buoyancy and cardiopulmonary sparing drug protocols to reduce the need for hemodynamic support of current protocols.

Effects of unilateral superimposed high-frequency jet ventilation on porcine hemodynamics and gas exchange during one-lung flooding.

Superimposed high-frequency jet ventilation (SHFJV) is suitable for respiratory motion reduction and essential for effective lung tumor ablation. Fluid filling of the target lung wing one-lung flooding (OLF) is necessary for therapeutic ultrasound applications. However, whether unilateral SHFJV allows adequate hemodynamics and gas exchange is unclear. To compared SHFJV with pressure-controlled ventilation (PCV) during OLF by assessing hemodynamics and gas exchange in different animal positions. SHFJV or PCV was used alternatingly to ventilate the non-flooded lungs of the 12 anesthetized pigs during OLF. The animal positions were changed from left lateral position to supine position (SP) to right lateral position (RLP) every 30 min. In each position, ventilation was maintained for 15 min in both modalities. Hemodynamic variables and arterial blood gas levels were repeatedly measured. Unilateral SHFJV led to lower carbon dioxide removal than PCV without abnormally elevated carbon dioxide levels. SHFJV slightly decreased oxygenation in SP and RLP compared with PCV; the lowest values of PaO2 and PaO2/FiO2 ratio were found in SP [13.0; interquartile range (IQR): 12.6-5.6 and 32.5 (IQR: 31.5-38.9) kPa]. Conversely, during SHFJV, the shunt fraction was higher in all animal positions (highest in the RLP: 0.30). In porcine model, unilateral SHFJV may provide adequate ventilation in different animal positions during OLF. Lower oxygenation and CO2 removal rates compared to PCV did not lead to hypoxia or hypercapnia. SHFJV can be safely used for lung tumor ablation to minimize ventilation-induced lung motion.

Characteristics of anesthetic and surgical tactics in treatment of a patient with a giant thyroid mass in a cancer center (clinical case)

This paper describes an example of radical surgical treatment of a patient with a giant retrosternal goiter complicated by compression of the organs of the neck and mediastinum. Considering all the risks and possible complications, we should take into account the fact that enlarged thyroid (T) body with retrosternal location can cause displacement and stenosis of the trachea and esophagus, and dislocation of large vessels and nerves of the mediastinum. This anatomical specificity is an imminent threat to successful treatment, and it also carries a certain risk of asphyxia and sudden death of the patient. In this clinical case, radical surgical treatment in this patient included sequential mobilization in two pleural cavities, and then the total removal of T through the traditional surgical access. The anesthetic complexity to support the surgical intervention involved both difficult intubation due to tracheal stenosis, and also the required separate ventilation of the lungs to visualize anatomical structures and mobilize a multinodular formation in two pleural cavities. Standard methods of artificial lung ventilation could be ineffective and even dangerous in this case due to the location and size of the tumor. We focused our attention on high-frequency ventilation (HFV), the best method of respiratory support during surgeries for tracheal and bronchial pathologies. The main task of the anesthetic team in this clinical case was to prevent the development of hypercapnia and hypoxia during intubation of the stenotic tracheal segment, and then adequate ventilation of the lungs with reduced area of proper gas exchange due to bilateral surgical pneumothorax. Thus, the full treatment was carried out due to the only safe method of compensating lung ventilation with anesthesia by HFV. The applied HFV method creates an adequate gas exchange in the lungs due to the small ventilation volume and high frequency of respiratory cycles per minute. HFV both prevented the development of threatening complications during intubation of the stenotic tracheal area and ensured an adequate gas exchange during successive thoracoscopic stages of thyroid tumor mobilization.

Effects of a stepwise alveolar recruitment maneuver on lung volume distribution in dogs assessed by computed tomography.

Pulmonary atelectasis is a commonly occurs during anesthesia. In these cases, mechanical ventilation (MV) associated with alveolar recruitment maneuvers (ARMs) and positive end-expiratory pressure (PEEP) is indicated to reverse the condition, ensure adequate gas exchange and improve oxygenation. ARMs can trigger volutrauma, barotrauma, and atelectrauma. Therefore, computed tomography (CT) is the gold-standard method for monitoring lung aeration after ARM. To evaluate lung volume distribution after stepwise ARMs using computed tomography (CT). Twelve dogs weighing 24.0 ± 6.0 kg, aged 3 ± 1 years, of both sexes and different breeds, underwent orchiectomy or ovariohysterectomy. The animals were anesthetized and ventilated in volume-controlled mode. ARMs were then initiated by positive end-expiratory pressure (PEEP) titration (5, 10, 15, and 20 cmH2O). CT scans, cardiovascular parameters, and ventilatory mechanics were evaluated at all time points. Data were assessed for normality using the Shapiro-Wilk test and a two-way analysis of variance, followed by a post-hoc Bonferroni test to identify differences between time points. Statistical significance was attributed to a value of p of <0.05. CT demonstrated that the ARMs increased ventilation throughout the lung, including the dependent regions, with volumes that increased and decreased proportionally with PEEP titration. When they reached PEEP 10 and 5 cmH2O descending (d), they remained significantly higher than those in PEEP 0 cmH2O (baseline). Static compliance improved about 40% at PEEP 10d and PEEP 5d compared to baseline. There was an increase in heart rate (HR) from PEEP 15 increasing (i) (74.5%) to PEEP 10d (54.8%) compared to baseline. Mean arterial blood pressure (MABP) decreased approximately 9% from PEEP 15i to PEEP 15d compared to baseline. Lung attenuation and regional and global volumes assessed by CT showed that maximum pulmonary aeration distribution followed by PEEP titration occurred at PEEP 20 cmH2O, maintaining the lungs normoaerated and without hyperaeration.

Anesthetic Aspects of Cytoreductive Surgery and Hyperthermic Intrathoracic Chemotherapy (HITHOC) in Treatment of Pleural Malignancies - Experiences from IORS

Background: Cytoreductive surgery (CRS) with hyperthermic intrathoracic chemotherapy (HITHOC) is a procedure that includes surgical removal of all visible tumor implants and intrathoracic application of gradually heated cytostatic solution. Numerous changes in hemodynamic, respiratory, core body temperature and metabolic parameters are possible during this complex procedure. The aim of this retrospective study was to analyze pathophysiological changes which occur during CRS + HITHOC procedure, and to suggest efficient strategies for perioperative patient care that might reduce complication rate. Methods: The study included 7 patients who underwent CRS + HITHOC in our cancer center. Enhanced Recovery After Surgery (ERAS) guideline for Thoracic Surgery was applied to all patients. Data on intraoperative hemodynamics (mean arterial pressure, stroke volume, heart rate, cardiac output) and temperature variations were collected from medical records and analyzed in three timelines: during the CRS phase, at the beginning, and the end of cytostatic perfusion. Occurrence of respiratory, renal, and cardiac complications was monitored. Results: All patients were respiratory stable during one-lung ventilation, with adequate gas exchange. Hemodynamic stability was compromised at the beginning of cytostatic perfusion, with significant decrease of mean arterial pressure and stroke volume. Two patients required vasopressor support. Average core body temperature was satisfactory in all patients. Coagulation disorders and acute renal failure were not recorded in postoperative period. One patient developed atrial fibrillation which was successfully pharmacologically restored. Conclusion: Our results indicate that goal directed fluid management following ERAS protocol, with maintaining hemodynamic stability and normothermia, could prevent perioperative complications during HITHOC procedure.

Anesthesia and Surgery of the Trachea

This article aims to review the current anaesthetic management of tracheal resections.Apart from the "traditional" approach of induction of general anaesthesia with conventional tracheal intubation and cross-field intubation or jet ventilation during the resection phase, there has lately been a trend towards less invasive techniques.Regional anaesthesia, laryngeal mask airways and preservation of spontaneous ventilation are among the new anaesthetic approaches. Current data suggest potential advantages compared with conventional tracheal intubation.Extracorporeal membrane oxygenation may provide adequate gas exchange and/or cardiovascular support for complex resections and reconstructions. In addition, it may serve as a reliable "backup" technique, in case of oxygenation difficulties with the use of other devices.Given the vast spectrum of different anaesthetic approaches to tracheal surgery, interdisciplinary planning is essential to identify the optimal technique on a case-by-case basis. During that process, the localisation and consistency of the airway lesion, comorbidities and the functional status of the respiratory system and specific surgical approach need to be taken into account.As there is a lack of high-quality data, evidence-based comparisons of different anaesthetic techniques are not possible.

Long-Term Outcomes of Extracorporeal Life Support in Respiratory Failure.

Although extracorporeal life support is an expensive method with serious risks of complications, it is nowadays a well-established and generally accepted method of organ support. In patients with severe respiratory failure, when conventional mechanical ventilation cannot ensure adequate blood gas exchange, veno-venous extracorporeal membrane oxygenation (ECMO) is the method of choice. An improvement in oxygenation or normalization of acid-base balance by itself does not necessarily mean an improvement in the outcome but allows us to prevent potential negative effects of mechanical ventilation, which can be considered a crucial part of complex care leading potentially to an improvement in the outcome. The disconnection from ECMO or discharge from the intensive care unit should not be viewed as the main goal, and the long-term outcome of the ECMO-surviving patients should also be considered. Approximately three-quarters of patients survive the veno-venous ECMO, but various (both physical and psychological) health problems may persist. Despite these, a large proportion of these patients are eventually able to return to everyday life with relatively little limitation of respiratory function. In this review, we summarize the available knowledge on long-term mortality and quality of life of ECMO patients with respiratory failure.

Incidence of nosocomial infection and causative microorganism during extracorporeal membrane oxygenation in adult patients, a single center study.

Extracorporeal membrane oxygenation (ECMO) is an organ support whose use is increasing in acute respiratory distress syndrome (ARDS) cases where adequate gas exchange cannot be achieved despite mechanical ventilation. Patients who were followed up on ECMO are at risk for developing nosocomial infections. In this study, we aimed to investigate the incidence of nosocomial infection and define isolated pathogens from microbiological samples in a single center in Turkey. Patients who were followed up on ECMO due to ARDS between January 1, 2018, and December 31, 2021, were included in the study. Nosocomial infections that were diagnosed after the first 48h of ECMO cannulation and after 48h of ECMO decannulation were accepted as ECMO-related infections. A total of 50 patients with ARDS were followed up with ECMO. Mean age of patients was 46,8 ± 15,4 and 38 (78%) patients were male. A total of 30 patients (60%) had at least one nosocomial infection, for a rate of 37.6 per 1000 ECMO days. COVID-19, steroid treatment, and ECMO duration were found to be associated with nosocomial infections in patients who underwent ECMO support. In multivariate analysis, antibiotic use was found to be protective against nosocomial infection (OR:0.14, 95% CI: 0.03 - 0.70, p = .017). In addition, prolonged ECMO duration was associated with an increased risk of nosocomial infection in multivariate analysis (OR:1.13, 95% CI: 1.03 - 1.23, p = .010). Gram-negative pathogens were isolated dominantly in blood cultures and tracheal secretion samples, followed by fungi and Gram-positive bacteria. Patients are prone to nosocomial infections during ECMO. Microorganisms causing nosocomial infections in ECMO patients seem similar to the flora of each center, and this should be taken into account in the choice of empirical antibiotics.

Total dead space in children under general anesthesia.

Total dead space in children under general anesthesia.

Inflammatory Biomarkers Affecting Survival Prognosis in Patients Receiving Veno-Venous ECMO for Severe COVID-19 Pneumonia.

Severe COVID-19 pneumonia in which mechanical ventilation is unable to achieve adequate gas exchange can be treated with veno-venous ECMO, eliminating the need for aggressive mechanical ventilation which might promote ventilator-induced lung injury and increase mortality. In this retrospective observational study, 18 critically ill COVID-19 patients who were treated using V-V ECMO during an 11-month period in a tertiary COVID-19 hospital were analyzed. Biomarkers of inflammation and clinical features were compared between survivors and non-survivors. Survival rates were compared between patients receiving ECMO and propensity matched mechanically ventilated controls. There were 7 survivors and 11 non-survivors. The survivors were significantly younger, with a higher proportion of females, higher serum procalcitonin at ICU admission, and before initiation of ECMO they had significantly lower Murray scores, PaCO2, WBC counts, serum ferritin levels, and higher glomerular filtration rates. No significant difference in mortality was found between patients treated with ECMO compared to patients treated using conventional lung protective ventilation. Hypercapnia, leukocytosis, reduced glomerular filtration rate, and increased serum ferritin levels prior to initiation of V-V ECMO in patients with severe COVID-19 pneumonia may be early warning signs of reduced chance of survival. Further multicentric studies are needed to confirm these findings.

Anatomical damage caused by Bacillus thuringiensis variety israelensis in yellow fever mosquito Aedes aegypti (L.) larvae revealed by micro-computed tomography

With micro-computed tomography techniques, using the single-distance phase-retrieval algorithm phase contrast, we reconstructed enhanced rendered images of soft tissues of Aedes aeqypti fourth instar larvae after Bti treatment. In contrast to previous publications based on conventional microscopy, either optical or electron microscopy, which were limited to partial studies, mostly in the form of histological sections, here we show for the first time the effects of Bti on the complete internal anatomy of an insect. Using 3D rendered images it was possible to study the effect of the bacterium in tissues and organs, not only in sections but also as a whole. We compared the anatomy of healthy larvae with the changes undergone in larvae after being exposed to Bti (for 30 min, 1 h and 6 h) and observed the progressive damage that Bti produce. Damage to the midgut epithelia was confirmed, with progressive swelling of the enterocytes, thickening epithelia, increase of the vacuolar spaces and finally cell lysis, producing openings in the midgut walls. Simultaneously, the larvae altered their motility, making it difficult for them to rise to the surface and position the respiratory siphon properly to break surface tension and breathe. Internally, osmotic shock phenomena were observed, resulting in a deformation of the cross-section shape, producing the appearance of a wide internal space between the cuticle and the internal structures and a progressive collapse of the tracheal trunks. Taken together, these results indicate the death of the larvae, not by starvation as a consequence of the destruction of the epithelia of the digestive tract as previously stated, but due to a synergic catastrophic multifactor process in addition to asphyxia due to a lack of adequate gas exchange.

SOLVe: a closed-loop system focused on protective mechanical ventilation

BackgroundMechanical ventilation is an essential component in the treatment of patients with acute respiratory distress syndrome. Prompt adaptation of the settings of a ventilator to the variable needs of patients is essential to ensure personalised and protective ventilation. Still, it is challenging and time-consuming for the therapist at the bedside. In addition, general implementation barriers hinder the timely incorporation of new evidence from clinical studies into routine clinical practice.ResultsWe present a system combing clinical evidence and expert knowledge within a physiological closed-loop control structure for mechanical ventilation. The system includes multiple controllers to support adequate gas exchange while adhering to multiple evidence-based components of lung protective ventilation. We performed a pilot study on three animals with an induced ARDS. The system achieved a time-in-target of over 75 % for all targets and avoided any critical phases of low oxygen saturation, despite provoked disturbances such as disconnections from the ventilator and positional changes of the subject.ConclusionsThe presented system can provide personalised and lung-protective ventilation and reduce clinician workload in clinical practice.

Awake Fiberoptic Intubation

We may have many devices in this 21st century, which can be used to secure the airway in patients who have been predicted to have a difficult airway. There are many studies about difficult airways and suggested various devices such as flexible fiberoptic scope, video laryngoscope, and the specialized intubating laryngeal mask airway and they ended up concluding one device better than another. Furthermore, ET intubation requires continued practice and carries with it its own set of complications. Technical problems with the placement of endotracheal tubes have been the most frequent cause of anesthetic deaths in published analyses from all over the world. The basic responsibility of an anesthesiologist is to maintain adequate gas exchange in patients by securing a patent airway through a proper device. Fiberoptic bronchoscopy and intubation have the advantage of being easier, with shorter intubation time and continuous oxygenation and ventilation throughout the procedure, especially in the case of children. We report two such cases, where “Awake flexible fiberoptic-guided intubation” was considered the only desirable choice.

Oxygen uptake ( O2) and pulmonary ventilation ( E) during military surface fin swimming in a swimming flume: Effects of surface immersion.

Introduction: During military fin swimming, we suspected that oxygen uptake ( O2) and pulmonary ventilation ( E) might be much higher than expected. In this framework, we compared these variables in the responses of trained military divers during land cycling and snorkeling exercises. Methods: Eighteen male military divers (32.3 ± 4.2years; 178.0 ± 5.0cm; 76.4 ± 3.4kg; 24.1 ± 2.1kgm-2) participated in this study. They performed two test exercises on two separate days: a maximal incremental cycle test (land condition), and an incremental fin swimming (fin condition) in a motorized swimming flume. Results: The respective fin and land O2max were 3,701 ± 39mLmin-1 and 4,029 ± 63mLmin-1 (p = 0.07), these values were strongly correlated (r 2 = 0.78 p < 0.01). Differences in O2max between conditions increased relative to l; O2max (r 2 = 0.4 p = 0.01). Fin E max values were significantly lower than land E max values (p = 0.01). This result was related to both the significantly lower fin Vt and f (p < 0.01 and <0.04, respectively). Consequently, the fin E max / O2max ratios were significantly lower than the corresponding ratios for land values (p < 0.01), and the fin and land E max were not correlated. Other parameters measured at exhaustion-PaO2, PaCO2, and SO2 - were similar in fin and land conditions. Furthermore, no significant differences between land and fin conditions were observed for peak values for heart rate, blood lactate concentration, and respiratory exchange ratio R. Conclusion: Surface immersion did not significantly reduce the O2max in trained divers relative to land conditions. As long as O2 remained below O2max , the E values were identical in the two conditions. Only at O2max was E higher on land. Although reduced by immersion, E max provided adequate pulmonary gas exchange during maximal fin swimming.