Positive Pressure Ventilation Research Articles

Optimizing ventilatory support in ARDS: A comprehensive guide for ICU nurses on patient care

The emergence of COVID-19 as a global pandemic has placed an unprecedented strain on healthcare systems worldwide, highlighting a critical shortage of trained healthcare professionals equipped to manage such a crisis. This deficit poses a significant challenge to the delivery of healthcare services, particularly in the context of intensive care units (ICUs) where the use of advanced medical technologies, such as ventilators, is paramount. For nurses with limited experience in ICU settings, navigating the complexities of invasive positive pressure ventilation (IPPV), a principal method of mechanical ventilation for critically ill patients can be daunting. This article aims to serve as a comprehensive guide for nurses less familiar with the intricacies of managing patients on IPPV, offering insights and strategies to enhance their competence and confidence in this critical aspect of patient care.

[Consensus on the procedure of balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension].

Chronic thromboembolic pulmonary hypertension (CTEPH) is classified as group IV pulmonary hypertension, characterized by thrombotic occlusion of the pulmonary arteries leading to vascular stenosis or obstruction, progressive increase in pulmonary vascular resistance and pulmonary arterial pressure, and eventual right heart failure. Unlike other types of pulmonary hypertension, the prognosis of CTEPH can be significantly improved by surgery, vascular intervention, and/or targeted drug therapy. Pulmonary endarterectomy (PEA) is the preferred treatment of choice for CTEPH. However, PEA is an invasive procedure with high operative risks, and is currently only performed in a few centers in China. Balloon pulmonary angioplasty (BPA) is an emerging interventional technique for CTEPH, serving as an alternative for patients who are ineligible for PEA or with residual pulmonary hypertension after PEA. BPA is gaining traction in China, but its widespread adoption is limited due to its complexity, operator skills, and equipment requirements, a lack of standard operating procedures and technical guidance, which limit the further improvement and development of BPA in China. To address this, a multidisciplinary panel of experts was convened to develop the Consensus on the Procedure of Balloon Pulmonary Angioplasty for the Chronic Thromboembolic Pulmonary Hypertension, which fomulates guidelines on BPA procedural qualification, perioperative management, procedural planning, technical approach, and complication prevention, with the aim of providing recommendations and clinical guidance for BPA treatment in CTEPH and standardizing its clinical application in this setting. Summary of recommendations: Recommendation 1: It is recommended that physicians who specialize in pulmonary vascular diseases take the lead in formulating the diagnostic and treatment plans for CTEPH, using a multidisciplinary approach.Recommendation 2: Training in BPA technique is critical; novice operators should undergo standardized operative training with at least 50 procedures under the guidance of experienced physicians before embarking on independent BPA procedures.Recommendation 3: BPA requires catheterization labs, angiography systems, standard vascular interventional devices and consumables, drugs, and emergency equipment.Recommendation 4: Patient selection for BPA should consider cardiac and pulmonary function, coagulation status, and comorbid conditions to determine indications and contraindications, thereby optimizing the timing of the procedure and improving safety.Recommendation 5: In experienced centers, patients deemed likely to benefit from early BPA, based on clinical and imaging features of CTEPH and without elevated D-dimer levels, could bypass standard 3-month anticoagulation therapy.Recommendation 6: BPA is a complex interventional treatment that requires thorough pre-operative assessment and preparation.Recommendation 7: The use of perioperative anticoagulants in BPA requires a comprehensive risk assessment of intraoperative bleeding by the operator for individualized decision making.Recommendation 8: A variety of venous access routes are available for BPA; unless contraindicated, the right femoral vein is usually preferred because of its procedural convenience and reduced radiation exposure.Recommendation 9: For the different types of vascular lesion in CTEPH, treatment of ring-like stenoses, web-like lesions, and subtotal occlusions should be prioritized before addressing complete occlusions and tortuous lesions, in order to reduce complications and improve procedural safety.Recommendation 10: A targeted, incremental balloon dilatation strategy based on vascular lesions is recommended for BPA.Recommendation 11: Intravascular pulmonary artery imaging technologies, such as OCT and IVUS can assist in accurate vessel sizing and confirmation of wire placement in the true vascular lumen. Pressure wires can be used to objectively assess the efficacy of dilatation during BPA.Recommendation 12: Endpoints for BPA treatment should be individually assessed, taking into account improvements in clinical symptoms, hemodynamics, exercise tolerance, and quality of life.Recommendation 13: Post-BPA routine monitoring of vital signs is essential; anticoagulation therapy should be initiated promptly post-procedure in the absence of complications. In cases of intraoperative hemoptysis, postoperative anticoagulation regimen adjustments should be adjusted according to the bleeding severity.Recommendation 14: If reperfusion pulmonary edema occurs during or after BPA, ensure adequate oxygenation, diuresis, and consider non-invasive positive-pressure ventilation if necessary, while severe cases may require early mechanical ventilation assistance or ECMO.Recommendation 15: In cases of intraoperative hemoptysis, temporary balloon occlusion to stop bleeding is recommended, along with protamine to neutralize heparin. Persistent bleeding may warrant the use of gelatin sponges, coil embolization, or covered stent implantation.Recommendation 16: For contrast imaging during BPA, non-ionic, low or iso-osmolar contrast agents are recommended, with hydration status determined by the patient's clinical condition, cardiac and renal function, and intraoperative contrast volume used.

Problems of operation of positive pressure ventilators on the basis of surveys of Polish officers of the State Fire Service

Positive pressure ventilators (PPV) used by 97.7% of officers of the National Fire Service in Poland, are characterized by work that is not in line with the expectations of the firefighters. In order to improve the technical and operational features of these devices, a survey was conducted among 25,000 eligible firefighters, identifying the application of these devices, problems in use and expected development directions. A total of 682 officers voluntarily completed the survey. Based on their findings, it was determined that ventilators are most often used to smoke out buildings after or during a fire. Mentioned problems when using these devices were mainly noise (78.2%), exhaust emissions (68.5%), and impediments to mobility through the device’s relatively heavy weight (40.2%). Other inconveniences were mentioned by less than 20% of firefighters. Polish firefighters expect the development of these devices mainly in terms of the above-mentioned features (noise reduction (81.7%) and reduction of the weight and size of the ventilators (about 50%)). Other expectations relate to the improvement of smoke removal in buildings: increasing the efficiency of smoke removal (46.4%) and efficiency regarding the rate of smoke removal in a building by increasing the size of the incoming airflow from the building’s surroundings (33.2%). About 15% of firefighters expect changes in the operation of the ventilator itself, that is, an increase in the effective operating time (electric ventilators) and an increase in the device’s uptime. The aim of the article is to identify the issues encountered during the operation and to indicate the expected direction of development for PPV by users. This information can be used by engineers to initiate new development work on these devices.

Retrospective evaluation of traumatic pneumomediastinum in dogs and cats (2005-2022): 52 cases.

To describe the incidence, etiology, clinical signs, diagnostics, treatments, and outcome of noniatrogenic traumatic pneumomediastinum (TPM) in dogs and cats. Retrospective study of cases (2005-2022). University veterinary teaching hospital. Fifty-two patients (29 dogs, 23 cats). Data collected from the medical records included signalment, physical examination findings, animal trauma triage (ATT) score, clinicopathological data, imaging data, surgical intervention, length of hospitalization, supportive care, complications, and outcome. Most dogs presented with tachycardia and tachypnea, while cats presented with hypothermia and tachypnea. Subcutaneous emphysema, pneumothorax, and dyspnea were the most common clinical signs for both species. The median calculated ATT score was 3.5 in dogs and 4 in cats. The most common radiographic abnormalities other than pneumomediastinum were pneumothorax and lung contusions. The overall mortality rate was 18%, with a significantly higher survival rate in dogs (26/28 dogs [93%], 15/22 cats (68%); P=0.03). Outcome was unknown in 1 dog and 1 cat. The only significant difference in treatment between survivors and nonsurvivors was the requirement in dogs for positive pressure ventilation. The median hospitalization period was 2days for both species, with a shorter hospitalization in the nonsurvivors (0.6 vs 2days, respectively; P=0.006). TPM is an infrequent pathology in veterinary medicine and may be seen without an externally obvious injury. The most common causes for TPM in dogs were vehicular trauma and bite wounds, while high-rise syndrome was the most common cause in cats. Most of the cases have concurrent pneumothorax and require thoracocentesis; however, direct intervention to treat TPM is not usually required. The vast majority of cases did not undergo surgery to treat TPM. The prognosis for dogs with TPM was good but was guarded for cats.

Clinical characteristics, complications and in-hospital mortality in patients in the coronary care unit requiring invasive mechanical ventilation

Abstract Funding Acknowledgements None. Introduction Mechanical ventilation (MV) is one of the most widely used life support techniques in critically ill patients and, due to the increasing number of coronary care units (CCU), adequate management of this technique is essential. Purpose The aim of our study was to describe the profile of patients requiring invasive MV (IMV) in our CCU, as well as the mode of ventilation, complications and in-hospital mortality. Methods Single-center retrospective observational study of a cohort of patients admitted to a CCU between January 2018 and March 2023 who required IMV. Baseline characteristics, reason for admission and intubation, as well as evolution and complications during admission were analyzed. Results A total of 157 patients were included, 113 (72%) men. The mean age was 66.9 years (SD 12.2). Table 1 summarizes the history and baseline characteristics of the patients. Image 1 summarizes the reasons for admission. Regarding the causes of oro-tracheal intubation, the most frequent was cardiopulmonary arrest (CPA) (49.7%), followed by respiratory failure (32.5%) and cardiogenic shock (CS) (16.6%). Regarding left ventricular ejection fraction (LVEF) on admission, 69.4% had LVEF<52%, with 32.5% of all patients having LVEF below 30%. The most used ventilation mode as initial mode was volume-controlled mode (VC/AC), used in 71.3% of patients. The mean stay in CCU was 11 (min 1-max 78, SD 12) and of orotracheal intubation was 5 days (min 1-max 64, SD 7). Mean days to weaning from VMI was 2 (min 0-max 8, SD 2). Failure on extubation occurred in 38 patients (19.1%), the most frequent reasons being need for reintubation (12.7%), need for noninvasive MV (8.9%) and self-extubation (2.5%). Only 7 patients (4.5%) required tracheostomy. Regarding complications, 49% developed sepsis, 61.1% had CS, and 7% required renal replacement therapy. In-hospital mortality was 38.2% (60 patients). Conclusions IMV is a technique that is increasingly used in our environment. Patients who require it are usually complex, with multiple comorbidities, with a high percentage of CPA and CS. These patients usually have prolonged stays in the CCU, with an average of more than 10 days, frequent complications and a high in-hospital mortality of almost 40%. It is essential to gather series as large as possible of these patients to improve our knowledge of their management and characteristics.

Study of gas exchange under different modes of ventilation in yoga breathing exercises

Yoga breathing exercises that develop the ability to voluntarily regulate the minute volume of respiration (MV) and maintain the state of hypoventilation, hypoxia and hypercapnia, can be considered as a way of hypoxic-hypercapnic training, potentially capable of influencing cerebral circulation and neuroprotective factors. However, at the moment, individual anthropometric features that affect the ability to develop a hypoventilation mode of breathing have not been studied, and methodological criteria for training have not been developed.Methods: The study involved 44 people (32 men and 12 women) who regularly practice yoga breathing techniques with a voluntary decrease in respiratory rate using maximum tidal volume (TV). Free breathing was recorded for 2 minutes, then each subject performed the respiratory hypoventilation pattern available to him or her (minimum RR values with maximum TV, inhalation and exhalation were of equal duration). The following parameters of external respiration were determined: respiratory rate (RR), minute ventilation (MV), tidal volume (TV), partial pressure of CO2 in the exhaled air at the end of exhalation (PetCO2 ), percentage of O2 in the exhaled air (FeO2) and hemoglobin saturation (SpO2 ).Results: Compared to breathing at rest (MV = M±SD 8.51 ± 2.57 (95% CI 7.72–9.29) l/min; PetCO2 = M±SD 36.98 ± 3.71 (95% CI 35.85–38.11) mm Hg), the mode with RR = 3 times/min (inspiration and expiration for 10 s), n = 44, leads to an increase in MV up to M±SD 12.02 ± 3.42 (95% CI 10.98–13.06) l/min (p < 0.001) and a decrease of CO2 : PetCO2 = M±SD 33.99 ± 3.59 (95% CI 32.90–35.08) mm Hg (p < 0.001) — that is, to development of alveolar hypocapnia. The mode with RR = 1.5 times/min (inhalation and exhalation for 20 s), n = 44, demonstrates a decrease in MV to M±SD 5.95 ± 1.59 (95% CI 5.46–6.43) l/min (p < 0.001) and growth of PetCO2 up to M±SD 41.19 ± 3.71 (95% CI 40.06–42.32) mm Hg (p < 0.001). The mode with RR = 1 time/min (inspiration and exhalation for 30 s), n = 24: with a decrease in RR to 1 time/min, a decrease in MV was observed to M±SD 4.22 ± 0.92 (95% CI 3.83–4.61) l / min (p < 0.001) and an increase in PetCO2 up to M±SD 44.05 ± 3.05 (95% CI 42.76–45.33) mm Hg (p < 0.001). The breathing pattern with RR = 1 r/min is accompanied by a statistically significant decrease in MV compared to rest, as well as an increase in PetCO2 and a decrease in FeO2 , that is, it is hypoventilation. We have proposed a ventilation coefficient (Qvent), which is the ratio MV/VC, which allows us to judge at what values of MV an individual reaches a state of hypoventilation. It was previously shown in this sample that the breathing exercise becomes hypoventilation when Qvent values are equal to or less than 1. With Qvent in the range from 1 to 2, the ventilation mode is within normal values, and when Qvent is more than 2, hyperventilation occurs.Conclusion: when performing yoga breathing exercises, variations in MV are observed both in the direction of hyperventilation and in the direction of hypoventilation with corresponding shifts in gas exchange (hypocapnia with hyperventilation, hypercapnia with hypoventilation). The MV values at which an individual reaches hypoventilation vary from person to person and can be predicted using the ventilation coefficient (Qvent).

PEEP trial and effect on hemodynamic in cardiogenic shock

Abstract Funding Acknowledgements None. Introduction Congestion is a paramount pathophysiological driver in patients with cardiogenic shock. Almost half of patients admitted due to cardiogenic shock undertake mechanical ventilation although ventilatory parameter, and their potential hemodynamic effect on the hemodynamic and congestion profile are often neglected. Purpose We sought to evaluate the hemodynamic effect of positive end-expiratory pressure (PEEP) titration on patients admitted to intensive care unit for CS. Methods We perform PEEP titration trial on patients undertaking mechanical ventilation for respiratory failure related to CS. The trial consisted in 3 steps of PEEP increase from 5 to 15 cmH2O. For each step arterial saturation, right atrial -RAP- and systemic blood pressure along with heart rate and respiratory mechanics (tidal volume-TV-, dynamic lung compliance- CLdyn, driving- Δ- and plateau pressure- Ppl) were measured. All the measures were taken at end-expiration; RAP trace was analyzed and systolic, mean and diastolic component collected. The final PEEP was decided based on the best matching between saturation, CLdyn and TV. Descriptive and repeated measures with Bonferroni correction were applied as statistical analysis (IBM SPSS 29). Results Twelve patients were included (10 male, 66 ± 7 years old; 8 acute myocardial infarction and 4 acute heart failure). At baseline the mean RAP was 8.44 (± 2.32) ; SBP 106 (IQR 92-112), HR 94 (IQR 88 - 102) Δ and Ppl pressures respectively 7.42 (± 0.79) and 12.08 (± 0.79, ),VT 427(± 65.42) and CLdyn 58.3 (± 7.1). The right atrial pressure (RAP) differed between AMI and AHDF (8.25 ± 2.25 vs 20.25 ± 1.5; p < 0.001), so HR did (113 ± 3.4 versus 96 ± 3.2 betas per minutes; p 0.015). RAP varied consistently during the PEEP trial (either sRAP, dRAP and mRAP- Table and Figure 1). The TV changed signficnatly between the 1st and 3rd step (p 0.004) and the CLdyn varied consistently throughout the 3 steps of the PEEP trial (p <0.001). A significant difference were observed according to aetiology in RAP (AMI Vs ADHF, eman difference 2.4 versus 4.3 mmHg) and in CLdyn (AMI Vs ADHF mean difference 12.31 vs 8 .65, p < 0.01) but not in the other parameters evaluated (p > 0.05). Conclusion This is the first, small, study evaluating the effect of positive pressure ventilation in CS patients according to etiologies. As previously demonstrated PEEP influences the right side hemodynamic by increasing the RAP, although resulting in better CLdyn. The extent of the effect of PEEP increased may be dependent on the underlying aetiology of CS. Considering that the sample size is extremely limited, these results advocate a wider validation. However, the positive pressures induced by the ventilation in patient with CS should be taken in consideration when the comprehensive evaluation of hemodynamic to define congestion profile and phenotype are performed.Table 1.Hemodynamic parametersGraph PEEP vs RAP

Surgical management of omega deformity in a patient with neurofibromatosis type 1: a case report.

To describe the surgical treatment in a patient with a partial omega deformity in the thoracic spine with neurofibromatosis type 1. The patient was a 55-year-old man with an omega deformity, which is defined as a curvature in which the end vertebra is positioned at the level of, above, or below the apical vertebra (i.e., a horizontal line bisecting it). We performed halo gravity traction (HGT) for 7weeks, followed by posterior spinal instrumented nearly equal in situ fusion from T2-L5 with three femoral head allografts and a local bone autograft. We avoided reconstruction of the thoracic anterior spine because of his severe pulmonary dysfunction. HGT improved the % vital capacity from 32.5 to 43.5%, and improved the Cobb angle of the kyphosis from > 180° before traction to 144° after traction. The Cobb angle of kyphosis and scoliosis changed from > 180° preoperatively to 155° and 146°, respectively, postoperatively, and 167° and 156°, respectively, at final follow-up. His postoperative respiratory function deteriorated transiently due to bilateral pleural effusions and compressive atelectasis, which was successfully treated with a frequent change of position and nasal high flow for 1week. At final follow-up, his pulmonary function improved from 0.86 to 1.04L in VC, and from 32.5 to 37.9% in %VC. However, there was no overall improvement in preoperative distress following surgery, although his modified Borg scale improved from 3 preoperatively to 0.5 postoperatively. One month after discharge, he felt worsening respiratory distress (SpO2:75%) and was readmitted for pulmonary hypertension for 2months. He was improved by non-invasive positive pressure ventilation (biphasic positive airway pressure) for 1week, medication and daily lung physiotherapy. Thereafter, he has been receiving permanent daytime (0.5L/min) and nighttime (2L/min) oxygen therapy at home. A solid arthrodesis through the fusion area was confirmed on computed tomography. However, the kyphosis correction loss was 12° (i.e., 155°-167°), while the scoliosis correction loss was 10° (i.e., 146°-156°) at 2years of recovery. We suggest that nearly equal in situ fusion is a valid option for preventing further deformity deterioration and avoiding fatal complications.

Low volume ventilation of pre-injured lungs degrades lung function via stress concentration and progressive alveolar collapse.

Mechanical ventilation can cause ventilation-induced lung injury (VILI). The concept of stress concentrations suggests that surfactant dysfunction-induced microatelectases might impose injurious stresses on adjacent, open alveoli and function as germinal centers for injury propagation. The aim of the present study was to quantify the histopathological pattern of VILI progression and to test the hypothesis that injury progresses at the interface between microatelectases and ventilated lung parenchyma during low positive end-expiratory pressure (PEEP) ventilation. Bleomycin was used to induce lung injury with microatelectases in rats. Lungs were then mechanically ventilated for up to 6 hours at PEEP=1cmH2O and compared to bleomycin treated group ventilated protectively with PEEP=5cmH2O to minimize microatelectases. Lung mechanics were measured during ventilation. Afterwards lungs were fixed at end-inspiration or end-expiration for design-based stereology. Prior to VILI, bleomycin challenge reduced the number of open alveoli (N(alvair,par)) by 29%. No differences between end-inspiration and end-expiration were observed. Collapsed alveoli clustered in areas with a radius up to 56 µm. After PEEP=5cmH2O ventilation for 6 hours, N(alvair,par) remained stable while PEEP=1cmH2O ventilation led to an additional loss of aerated alveoli by 26%, mainly due to collapse, with a small fraction partly edema filled. Alveolar loss strongly correlated to worsening of tissue elastance, quasi-static compliance and inspiratory capacity. The radius of areas of collapsed alveoli increased to 94 µm, suggesting growth of the microatelectases. These data provide evidence that alveoli become unstable in neighborhood of microatelectases which most likely occurs due to by stress concentration-induced local vascular leak and surfactant dysfunction.

Clinical characteristics and the prognostic impact of acute kidney injury in critically ill patients with invasive pulmonary Aspergillosis in the intensive care unit: A retrospective, single-center study

Introduction: The incidence and impact of acute kidney injury (AKI) in patients with invasive pulmonary aspergillosis (IPA) admitted to the intensive care unit (ICU) are unknown. Methods: This retrospective study included 140 patients who were diagnosed IPA and admitted to the medical ICU of China–Japan Friendship Hospital in Beijing, China. AKI was defined according to the kidney disease improving global outcomes guidelines. Data on demographic characteristics, comorbidities, laboratory tests, treatments, and prognosis at ICU admission were collected. Results: The rate of AKI was 71.4% (n = 100), and approximately 30% of the patients had preadmission acute kidney dysfunction. Of the 100 patients with AKI, 19, 8, and 73 patients had stage I, II, and III AKI, respectively, and 64 (87.6%) patients required continuous renal replacement therapy. Overall ICU mortality rate was 52.1%. Irreversible AKI was a strong independent risk factor for ICU mortality (odds ratio 13.36, 95% confidence interval 4.52–39.48, p < 0.001), followed by chronic lung disease, use of intermittent positive-pressure ventilation, and long-term corticosteroid treatment within 1 year prior to ICU admission. Higher cardiac troponin I levels at admission and worse volume control during the first 7 days of ICU stay were potential predictive factors of irreversible kidney dysfunction. Patients with irreversible AKI and those who died during the ICU stay had greater volume overload during the first 14 days of ICU stay. Patients who survived received earlier renal replacement therapy support after ICU admission compared to those who died (median, 2 vs. 5 days; p = 0.026). Conclusion: Compared to the patients with IPA in the absence of AKI, those with AKI presented with more volume overload, worse disease burden, and required stronger respiratory support, while experiencing worse prognosis. Irreversible AKI was a strong predictor of mortality in patients with critical IPA. Better volume control and earlier CRRT initiation should be considered key points in AKI management and prognostic improvement.

Sonographic assessment of the diaphragm in COVID 19 and non-COVID ICU patients

BackgroundSonographic evaluation of the diaphragm has gained popularity in the ICU due to the necessity of assessing diaphragmatic function in a variety of clinical situations. The sonographic examination of diaphragmatic dynamics in ICU patients by measuring diaphragmatic thickness and excursion in connection to various modalities of mechanical ventilation (MV) and patient outcomes was the objective of this study.MethodsThis prospective observational study was carried out on 50 patients in respiratory ICU in Kafr Elsheikh and Benha University Hospitals. Patients were classified into 2 equal groups: COVID-19 group and non-COVID group. All patients underwent ultrasound assessment included the diaphragm thickness fraction and excursion in ICU patients on admission and on weaning.ResultsSuccessful weaning (SW) was higher in group I compared to group II. In group I (COVID), diaphragm excursion, thickness at end inspiration and at end expiration in NIV at weaning were significantly higher in patients with SW but thickness at end expiration on admission was significantly lower. In group II (non-COVID) MV patients, excursion at weaning was significantly higher in patients with SW, also were thickness at end inspiration and end expiration on admission, thickness at end inspiration and end expiration at weaning in NIV patients but thickness at end inspiration in MV on admission was significantly lower.ConclusionWeaning success and mortality were significantly predicted by excursion in NIV at weaning, thickness at end inspiration in MV at weaning, thickness at end inspiration in NIV at weaning, and thickness at end expiration in MV at weaning.

The effect of NHFOV on hemodynamics in mild and moderately preterm neonates: a randomized clinical trial.

The aim of this study is to study cardio-respiratory effects of nasal high-frequency oscillatory ventilation (NHFOV) vs. NCPAP as an initial mode of ventilation in moderate-late-preterm infants. A randomized controlled trial was conducted in NICU of Alexandria University Maternity Hospital (AUMH). One-hundred late-moderate-preterm infants were randomly assigned to either NHFOV-group (n = 50) or NCPAP-group (n = 50). For both groups, functional echocardiography was performed in the first 24h to detect hemodynamic changes and respiratory outcome was monitored throughout the hospital stay. The main outcomes were hemodynamic measurements and myocardial function using functional echocardiography of those infants along with the respiratory outcome and complications. Kaplan-Meier survival plot was used representing time course of NCPAP and NHFOV failure. Left ventricular output values were not significantly different in both groups with median 202ml/kg /min and IQR (176-275) in NCPAP-group and 226ml/kg/min with IQR (181-286) in NHFOV group. Nevertheless, ejection fraction and fractional shortening were significantly higher in NHFOV-group with P 0.001. The time to weaning, the time to reach 30%-FIO2, the need for invasive ventilation, oxygen support duration, and maximal-FIO2 were significantly more in NCAPAP group. Conclusion: NHFOV is an effective and promising tool of non-invasive-ventilation which can be used as a primary modality of respiratory support in preterm infants with variable forms of respiratory distress syndrome without causing detrimental effect on hemodynamics or significant respiratory complications. Trial registration: NCT05706428 (registered on January 21, 2023). What is Known: • NHFOV might be beneficial as a secondary mode of ventilation and might have an impact on hemodynamics. What is New: • NHFOV can be used as an initial mode of ventilation with CDP beyond the reported pressure limits of CPAP without causing neither CO2 retention nor adverse hemodynamic consequences.

Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) reduces extubation failures in preterm neonates-A systematic review and meta-analysis.

To analyse the evidence of non-invasive neurally adjusted ventilatory assist (NIV-NAVA) in preterm neonates compared to nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure ventilation (NIPPV). We performed a systematic review and meta-analysis of randomised controlled trials and included studies where NIV-NAVA was analysed in preterm (<37 gestational weeks) born neonates. Our main outcomes were the need for endotracheal intubation, the need for surfactant therapy, and reintubation rates. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated. A total of five studies were included. The endotracheal intubation rate was 25% in the NIV-NAVA group and 26% in the nCPAP group (RR 0.91, CI: 0.56-1.48). The respective rates for surfactant therapy were 30% and 35% (RR 0.85, CI: 0.56-1.29). The reintubation rate in neonates previously invasively ventilated was 8% in the NIV-NAVA group and 29% in the nCPAP/NIPPV group (RR 0.29, 95%CI: 0.10-0.81). Evidence certainty was rated as low for all outcomes. NIV-NAVA as the primary respiratory support did not reduce the need for endotracheal intubation or surfactant therapy. NIV-NAVA seemed to reduce the reintubation rate after extubation in pre-term neonates.

Inconsistent Methods Used to Set Airway Pressure Release Ventilation in Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Regression Analysis.

Airway pressure release ventilation (APRV) is a protective mechanical ventilation mode for patients with acute respiratory distress syndrome (ARDS) that theoretically may reduce ventilator-induced lung injury (VILI) and ARDS-related mortality. However, there is no standard method to set and adjust the APRV mode shown to be optimal. Therefore, we performed a meta-regression analysis to evaluate how the four individual APRV settings impacted the outcome in these patients. Methods: Studies investigating the use of the APRV mode for ARDS patients were searched from electronic databases. We tested individual settings, including (1) high airway pressure (PHigh); (2) low airway pressure (PLow); (3) time at high airway pressure (THigh); and (4) time at low pressure (TLow) for association with PaO2/FiO2 ratio and ICU length of stay. Results: There was no significant difference in PaO2/FiO2 ratio between the groups in any of the four settings (PHigh difference -12.0 [95% CI -100.4, 86.4]; PLow difference 54.3 [95% CI -52.6, 161.1]; TLow difference -27.19 [95% CI -127.0, 72.6]; THigh difference -51.4 [95% CI -170.3, 67.5]). There was high heterogeneity across all parameters (PhHgh I2 = 99.46%, PLow I2 = 99.16%, TLow I2 = 99.31%, THigh I2 = 99.29%). Conclusions: None of the four individual APRV settings independently were associated with differences in outcome. A holistic approach, analyzing all settings in combination, may improve APRV efficacy since it is known that small differences in ventilator settings can significantly alter mortality. Future clinical trials should set and adjust APRV based on the best current scientific evidence available.

Non-invasive high-frequency ventilation in newborn infants with respiratory distress.

Respiratory distress occurs in up to 7% of newborns, with respiratory support (RS) provided invasively via an endotracheal (ET) tube or non-invasively via a nasal interface. Invasive ventilation increases the risk of lung injury and chronic lung disease (CLD). Using non-invasive strategies, with or without minimally invasive surfactant, may reduce the need for mechanical ventilation and the risk of lung damage in newborn infants with respiratory distress. To evaluate the benefits and harms of nasal high-frequency ventilation (nHFV) compared to invasive ventilation via an ET tube or other non-invasive ventilation methods on morbidity and mortality in preterm and term infants with or at risk of respiratory distress. We searched CENTRAL, MEDLINE, Embase, CINAHL and three trial registries in April 2023. Randomised controlled trials (RCTs), cluster- or quasi-RCTs of nHFV in newborn infants with respiratory distress compared to invasive or non-invasive ventilation. Two authors independently selected the trials for inclusion, extracted data, assessed the risk of bias, and undertook GRADE assessment. We identified 33 studies, mostly in low- to middle-income settings, that investigated this therapy in 5068 preterm and 46 term infants. nHFV compared to invasive respiratory therapy for initial RS We are very uncertain whether nHFV reduces mortality before hospital discharge (RR 0.67, 95% CI 0.20 to 2.18; 1 study, 80 infants) or the incidence of CLD (RR 0.38, 95% CI 0.09 to 1.59; 2 studies, 180 infants), both very low-certainty. ET intubation, death or CLD, severe intraventricular haemorrhage (IVH) and neurodevelopmental disability (ND) were not reported. nHFV vs nasal continuous positive airway pressure (nCPAP) used for initial RS We are very uncertain whether nHFV reduces mortality before hospital discharge (RR 1.00, 95% CI 0.41 to 2.41; 4 studies, 531 infants; very low-certainty). nHFV may reduce ET intubation (RR 0.52, 95% CI 0.33 to 0.82; 5 studies, 571 infants), but there may be little or no difference in CLD (RR 1.35, 95% CI 0.80 to 2.27; 4 studies, 481 infants); death or CLD (RR 2.50, 95% CI 0.52 to 12.01; 1 study, 68 participants); or severe IVH (RR 1.17, 95% CI 0.36 to 3.78; 4 studies, 531 infants), all low-certainty evidence. ND was not reported. nHFV vs nasal intermittent positive-pressure ventilation (nIPPV) used for initial RS nHFV may result in little to no difference in mortality before hospital discharge (RR 1.86, 95% CI 0.90 to 3.83; 2 studies, 84 infants; low-certainty). nHFV may have little or no effect in reducing ET intubation (RR 1.33, 95% CI 0.76 to 2.34; 5 studies, 228 infants; low-certainty). There may be a reduction in CLD (RR 0.63, 95% CI 0.42 to 0.95; 5 studies, 307 infants; low-certainty). A single study (36 infants) reported no events for severe IVH. Death or CLD and ND were not reported. nHFV vs high-flow nasal cannula (HFNC) used for initial RS We are very uncertain whether nHFV reduces ET intubation (RR 2.94, 95% CI 0.65 to 13.27; 1 study, 37 infants) or reduces CLD (RR 1.18, 95% CI 0.46 to 2.98; 1 study, 37 participants), both very low-certainty. There were no mortality events before hospital discharge or severe IVH. Other deaths, CLD and ND, were not reported. nHFV vs nCPAP used for RS following planned extubation nHFV probably results in little or no difference in mortality before hospital discharge (RR 0.92, 95% CI 0.52 to 1.64; 6 studies, 1472 infants; moderate-certainty). nHFV may result in a reduction in ET reintubation (RR 0.42, 95% CI 0.35 to 0.51; 11 studies, 1897 infants) and CLD (RR 0.78, 95% CI 0.67 to 0.91; 10 studies, 1829 infants), both low-certainty. nHFV probably has little or no effect on death or CLD (RR 0.90, 95% CI 0.77 to 1.06; 2 studies, 966 infants) and severe IVH (RR 0.80, 95% CI 0.57 to 1.13; 3 studies, 1117 infants), both moderate-certainty. We are very uncertain whether nHFV reduces ND (RR 0.92, 95% CI 0.37 to 2.29; 1 study, 74 infants; very low-certainty). nHFV versus nIPPV used for RS following planned extubation nHFV may have little or no effect on mortality before hospital discharge (RR 1.83, 95% CI 0.70 to 4.79; 2 studies, 984 infants; low-certainty). There is probably a reduction in ET reintubation (RR 0.69, 95% CI 0.54 to 0.89; 6 studies, 1364 infants), but little or no effect on CLD (RR 0.88, 95% CI 0.75 to 1.04; 4 studies, 1236 infants); death or CLD (RR 0.92, 95% CI 0.79 to 1.08; 3 studies, 1070 infants); or severe IVH (RR 0.78, 95% CI 0.55 to 1.10; 4 studies, 1162 infants), all moderate-certainty. One study reported there might be no difference in ND (RR 0.88, 95% CI 0.35 to 2.16; 1 study, 72 infants; low-certainty). nHFV versus nIPPV following initial non-invasive RS failure nHFV may have little or no effect on mortality before hospital discharge (RR 1.44, 95% CI 0.10 to 21.33); or ET intubation (RR 1.23, 95% CI 0.51 to 2.98); or CLD (RR 1.01, 95% CI 0.70 to 1.47); or severe IVH (RR 0.47, 95% CI 0.02 to 10.87); 1 study, 39 participants, all low- or very low-certainty. Other deaths or CLD and ND were not reported. For initial RS, we are very uncertain if using nHFV compared to invasive respiratory therapy affects clinical outcomes. However, nHFV may reduce intubation when compared to nCPAP. For planned extubation, nHFV may reduce the risk of reintubation compared to nCPAP and nIPPV. nHFV may reduce the risk of CLD when compared to nCPAP. Following initial non-invasive respiratory support failure, nHFV when compared to nIPPV may result in little to no difference in intubation. Large trials, particularly in high-income settings, are needed to determine the role of nHFV in initial RS and following the failure of other non-invasive respiratory support. Also, the optimal settings of nHVF require further investigation.

Mechanical ventilation: Beyond the basics.

Mechanical ventilation is rarely a simple matter. Skill and knowledge are required to operate the ventilator modes, choose the optimal settings, and understand many monitored variables. Supporting the patient safely and effectively is the top priority in providing mechanical ventilation. This article discusses mechanical ventilation in adults.

Numerical investigation of evaporative cooling strategies on the aero-thermal performance of courtyard buildings in hot-dry climates

In hot and dry urban environments, courtyards help mitigate extreme heat and influence the urban microclimate. These structures not only provide light and private outdoor spaces but also aid in mitigating the urban heat island (UHI) effect through improved airflow and evapotranspiration. Courtyards, being central open-air areas enclosed by buildings, are crucial in creating opportunities for natural ventilation driven by wind and buoyancy-induced forces, thus serving as a microclimatic regulator. This study investigates the role of courtyards in modulating their microclimate and adjacent indoor areas by integrating evaporative cooling strategies to enhance cooling in these spaces. While numerous studies have been conducted on the role of water bodies in evaporative cooling, the aero-thermal impact on adjacent indoor spaces remains less understood. Addressing this gap, the present research explores the effect of an evaporative cooling system on the wind and thermal conditions within a courtyard and examines different natural ventilation modes, namely, single-sided and crossflow ventilation, in indoor spaces. A computational fluid dynamics (CFD) model, validated against wind tunnel experimental data, was employed to simulate various evaporative cooling water spray configurations. The results reveal complex courtyard microclimates with diverse cooling effects influenced by room orientation and floor level. Specifically, in single-sided ventilated courtyards, water sprays significantly improved the indoor thermal environment, with the average temperature across all rooms decreased by 2.06 °C, and humidity increased by 4.29 %. However, in cross-ventilated courtyards, water sprays' cooling and humidifying effects were relatively less effective. This research underscores the potential of evaporative cooling technology in improving the microclimate of courtyards, with practical applications extending to urban design and architecture. By tailoring cooling strategies to specific courtyard configurations, urban planners and architects significantly improve indoor comfort levels and energy efficiency.

Utilizing periodic boundary conditions to save computational resources for assessing building natural ventilation in urban areas

For the first time in literature, we innovatively conducted CFD simulations with periodic boundary conditions to predict coupled indoor-outdoor airflows for a full-scale 3D six-floor residential building unit in urban areas with uniformly building clusters. A few influencing parameters on building ventilation performance are comprehensively analyzed, including the impacts of the surrounding buildings, wind incident angle (θ), external opening designs, cross or single-sided ventilation modes, and indoor facilities. Ventilation evaluation is contingent on factors including air change rate per hour (ACH), the corresponding ACH of purging flow rate (ACHPFR), and age of air (τ).Results show that the efficiency of natural ventilation on each floor differs from previous research conclusions after considering the impacts of surrounding buildings. Single-sided ventilation is significantly less effective than cross-ventilation in all scenarios. Most cross-ventilation cases have one-order greater ACH and ACHPFR values compared to those with single-sided ventilation. The window-to-wall ratio on the windward and leeward sides can affect the natural ventilation rate of the corresponding rooms. A large leeward opening helps to increase the ventilation rate, especially for the rooms on the upper floor, but it decreases the ventilation for the rooms near the ground. Indoor furniture has an insignificant impact on outdoor airflow and natural ventilation efficiency.

Effectiveness of Nursing Strategies on Risk for Pneumonia Among Patients Connected to Mechanical Ventilator in Intensive Care Unit

It has been reported that the incidence of nosocomial infections in the ICU is about 2–5 times higher than in the general in-patient hospital population. The study's objective was to evaluate the effectiveness of Nursing Strategies on Risk for Pneumonia among Patients connected to Mechanical Ventilator in Intensive Care Unit. The study adopted randomized controlled trial. Forty patients were enrolled in the study after screening using CPIS scale. If the score &lt;6 the patients were included in the study and eligibility criteria were age between 25 to 60 years, duration of ventilator 48 hours and medical patients with respiratory, renal, MODS, and sepsis diagnosis. Patients subjected to surgery and connected with non-invasive ventilation were excluded from the study. Standardized questionnaire such as demographic variables, clinical variables, and Clinical Pulmonary Infection Scoring (CPIS). The data was analyzed using descriptive statistics, independent ‘t’ test, paired t test and ANOVA were used to analyze the data. Seven (35%) of them were in the age group of 51-60 years in the study group, whereas six (30%) of the patients were in the age group of 61-70 years in the control group. 12(60%) of the patients were male and eight (40%) of them were female in the study group and 10(50%) of patients were male and female respectively in the control group. Regarding mode of ventilation, 12(50%) and six (30%) of patients ventilator setting were CMV and ASV respectively, in the study group, whereas seven (35%) and six (30%) of patients ventilator settings were ASV and CMV respectively in the control group. The pretest CPIS mean score was 4.40 with a standard deviation of 0.59 and the posttest III mean value was 2.60 with a standard deviation of 0.58 and the mean difference was 1.80 between the pretest and the posttest III, which was statistically significant at p&lt;0.001 in the study group. Nursing strategies such as demand suctioning, second hourly position change, changing ventilator flow sensor every 72 hours, and oral care every fourth hour with chlorhexidine help reduce ventilator-associated pneumonia.

A New Approach to the Economic Evaluation of Thermomodernization: Annual Assessment Based on the Example of Production Space

Energy and economic assessments are of great relevance in the context of decision processes for the most optimal solutions for building renovations. Following the method recommended by UNIDO, economic analyses of thermal modernization options are carried out based on the Simple Payback Time (SPBT), Net Present Value Ratio (NPVR) and Internal Rate of Return (IRR) indices. Incorporating these indicators and a new approach that involves aggregating thermomodernization activities not only in the cold and warm seasons separately, but throughout the whole year, an economic evaluation of the thermomodernization of a production space was carried out. In this case study, the renovation options included wall insulation, window replacement, the installation of infrared heater, a two-flow air diffuser (TFAD) and variable air volume. The economic effect indicated by the highest NPVR over a normative period of 15 years was obtained for the installation of an infrared heater and a TFAD with a variable mode ventilation system. The SPBT for this case was also the lowest.