The Effects of Different Pressure Pneumoperitoneum on the Pulmonary Mechanics and Surgical Satisfaction in the Laparoscopic Cholecystectomy

Objectives. Inspiratory, hemodynamic and metabolic changes occur in laparoscopic surgery depending on pneumoperitoneum and patient position. This study aims to evaluate the effects of intra-abdominal pressure increase based on CO2 pneumoperitoneum in laparoscopic operations on hemodynamic parameters and respiratory dynamics and satisfaction of surgeon and operative view.Materials and Methods. A total of 116 consecutive, prospective, ASA class I–III cases aged 18–70 years undergoing laparoscopic cholecystectomy were enrolled in this study. Data of 104 patients were analysed. Patients were divided into two groups as the group Low Pressure (<12 mmHg) (Group LP) (n=53) and the group Standard Pressure (>13 mmHg) (Group SP) (n=51). In this study administration of general anesthesia used total intravenous anaesthesia in both groups. All groups had standard and TOF monitorization applied. The anaesthesia methods used in both groups were recorded. Before, during and after peritoneal insufflation, the peroperative ventilation parameters and hemodynamic parameters were recorded. The adequacy of pneumoperitoneum, gastric and the operative view were evaluated by the operating surgeon and recorded.Results. The peripheral oxygen saturation showed no significant difference between the low and standard pressure pneumoperitoneum in view of tidal volume, respiratory rate, end tidal CO2, mean and peak inspiratory pressure, and minute ventilation values. In terms of hemodynamics, when values just after intubation and before extubation were compared, it was observed that in the LP group systolic, diastolic and mean blood pressure values were higher. In terms of heart rate, no significant difference was observed in determined periods between groups. There was no significant difference between the groups in terms of surgical satisfaction and vision.Conclusion. Low pressure pneumoperitoneum provides effective respiratory mechanics and stable hemodynamics for laparoscopic cholecystectomy. It also provides the surgeon with sufficient space for hand manipulations. Anaesthetic method, TIVA and neuromuscular blockage provided good surgery vision with low pressure pneumoperitoneum.

Aerosol Delivery of Surfactant Liposomes for Management of Pulmonary Fibrosis: An Approach Supporting Pulmonary Mechanics

Excessive architectural re-modeling of tissues in pulmonary fibrosis due to proliferation of myofibroblasts and deposition of extracellular matrix adversely affects the elasticity of the alveoli and lung function. Progressively destructive chronic inflammatory disease, therefore, necessitates safe and effective non-invasive airway delivery that can reach deep alveoli, restore the surfactant function and reduce oxidative stress. We designed an endogenous surfactant-based liposomal delivery system of naringin to be delivered as an aerosol that supports pulmonary mechanics for the management of pulmonary fibrosis. Phosphatidylcholine-based liposomes showed 91.5 ± 2.4% encapsulation of naringin, with a mean size of 171.4 ± 5.8 nm and zeta potential of −15.5 ± 1.3 mV. Liposomes with the unilamellar structure were found to be spherical and homogeneous in shape using electron microscope imaging. The formulation showed surface tension of 32.6 ± 0.96 mN/m and was able to maintain airway patency of 97 ± 2.5% for a 120 s test period ensuring the effective opening of lung capillaries and deep lung delivery. In vitro lung deposition utilizing Twin Stage Impinger showed 79 ± 1.5% deposition in lower airways, and Anderson Cascade Impactor deposition revealed a mass median aerodynamic diameter of 2.35 ± 1.02 μm for the aerosolized formulation. In vivo efficacy of the developed formulation was analyzed in bleomycin-induced lung fibrosis model in rats after administration by the inhalation route. Lactate dehydrogenase activity, total protein content, and inflammatory cell infiltration in broncho-alveolar lavage fluid were substantially reduced by liposomal naringin. Oxidative stress was minimized as observed from levels of antioxidant enzymes. Masson’s Trichrome staining of lung tissue revealed significant amelioration of histological changes and lesser deposition of collagen. Overall results indicated the therapeutic potential of the developed non-invasive aerosol formulation for the effective management of pulmonary fibrosis.

The physiology of singing and implications for ‘Singing for Lung Health’ as a therapy for individuals with chronic obstructive pulmonary disease

Singing is an increasingly popular activity for people with chronic obstructive pulmonary disease (COPD). Research to date suggests that ‘Singing for Lung Health’ may improve various health measures, including health-related quality-of-life. Singing and breathing are closely linked processes affecting one another. In this narrative review, we explore the physiological rationale for ‘Singing for Lung Health’ as an intervention, focusing on the abnormalities of pulmonary mechanics seen in COPD and how these might be impacted by singing. The potential beneficial physiological mechanisms outlined here require further in-depth evaluation.

Evaluation of the influence of individualized protective ventilation on the lung mechanical properties

The work is devoted to the study of the influence of individualized protective ventilation support on pulmonary mecha-nics. The study included 47 patients who underwent open abdominal surgery under general anesthesia. All patients had a moderate to high risk of developing postoperative pulmonary complications by the ARISCAT scale. Intraoperatively, the impact of individualized protective ventilation on respiratory mechanics, namely Ppeak, Pplat, Pdrive, dynamic pulmonary compliance was assessed. Individualized protective respiratory support was ventilation with a tidal volume of 7 ml/kg of ideal body weight, with the selection of the optimal level of positive pressure at the end of exhalation (PEEP), focusing on dynamic pulmonary compliance and performing recruiting maneuver, and then in the case of a decrease in dynamic pulmonary compliance by more than 20 %, followed by re-selection of PEEP. The studied parameters were recorded before and after the recruiting maneuver, as well as on the 30th, 60th, 90th, 120th, 150th, 180th minutes after the recruiting maneuver, depending on the duration of the operation. The use of alveolar straightening techniques led to an improvement in pulmonary mechanics, namely, an increase in dynamic pulmonary compliance by 16 % and a decrease in Pdrive by 17 %. The intraoperative level of PEEP averaged 4 [4; 5] cm of water. No cases of hypoxemia or recurrence of recruiting maneuver were reported. The obtained results indicate that chosen technique of recruiting maneuver is effective and safe, and its use allows reducing the negative impact of mechanical ventilation. The study did not find a statistically significant correlation between the level of PEEP and the value of dynamic pulmonary compliance. Such data prove the need for individual selection of ventilation parameters according to the characteristics of the mechanical properties of each patient.

Validation of the Modified Integrative Weaning Index as a Predictor of Weaning from Mechanical Ventilation in Comparison to Conventional Weaning Indices in Adult Critically Ill Patients

Introduction Timely recognition of the return to spontaneous ventilation is essential for reducing costs, morbidity, and mortality. Delays in both removing invasive ventilatory support and excessively early removal are correlated with complications that vary according to the severity of the underlying disease. Several weaning indices and predictors were studied in an attempt to evaluate the outcome of removing ventilatory support. However, none of them have yet presented good results in discriminating the outcome of extubation, even those most used in clinical practices. Aim The aim of this study is to validate the modified integrative weaning index (mIWI) as a reliable weaning index in comparison to the conventional weaning indices in the weaning of critically ill patients from invasive mechanical ventilation. Patients Four hundred patients, above the age of 18 years, on mechanical ventilation for more than 48 hours through an endotracheal tube for any cause were randomly assigned to this study. Methods patients ready to be weaned were assessed using mIWI and conventional indices and monitored for 48 hours. The performance of the indices were assessed in both successful and unsuccessful groups. Results The performance of the mIWI was not significantly superior to the conventional weaning indices in predicting weaning success or failure than the traditional weaning indices. The cut-off value for the predicting successful weaning from mechanical ventilation for the mIWI was higher than suggested by the original study and yet in agreement with some other studies. The cut-off value for the mIWI is higher in patients above the age of 60 years. Conclusion The results of the study revealed that the mIWI is a good predictor of weaning from mechanical ventilation and assessment of pulmonary mechanics and is not significantly superior to the traditional weaning indices, yet is not a good predictor for extubation success.

Coagulation Dysfunction in Acute Respiratory Distress Syndrome and Its Potential Impact in Inflammatory Subphenotypes

The Acute Respiratory Distress Syndrome (ARDS) has caused innumerable deaths worldwide since its initial description over five decades ago. Population-based estimates of ARDS vary from 1 to 86 cases per 100,000, with the highest rates reported in Australia and the United States. This syndrome is characterised by a breakdown of the pulmonary alveolo-epithelial barrier with subsequent severe hypoxaemia and disturbances in pulmonary mechanics. The underlying pathophysiology of this syndrome is a severe inflammatory reaction and associated local and systemic coagulation dysfunction that leads to pulmonary and systemic damage, ultimately causing death in up to 40% of patients. Since inflammation and coagulation are inextricably linked throughout evolution, it is biological folly to assess the two systems in isolation when investigating the underlying molecular mechanisms of coagulation dysfunction in ARDS. Although the body possesses potent endogenous systems to regulate coagulation, these become dysregulated and no longer optimally functional during the acute phase of ARDS, further perpetuating coagulation, inflammation and cell damage. The inflammatory ARDS subphenotypes address inflammatory differences but neglect the equally important coagulation pathway. A holistic understanding of this syndrome and its subphenotypes will improve our understanding of underlying mechanisms that then drive translation into diagnostic testing, treatments, and improve patient outcomes.

Trajectories of Hypoxemia & Pulmonary Mechanics of COVID-19 ARDS in the NorthCARDS Dataset

Background: Understanding heterogeneity seen in patients with COVIDARDS and comparing to non-COVIDARDS may inform tailored treatments. Methods: A multidisciplinary team of frontline clinicians and data scientists worked to create the Northwell COVIDARDS dataset (NorthCARDS) leveraging over 11,542 COVID-19 hospital admissions. The data was then summarized to examine descriptive differences based on clinically meaningful categories of lung compliance, and to examine trends in oxygenation. Findings: Of the 1595 COVIDARDS patients in the NorthCARDS dataset, there were 538 (34·6%) who had very low lung compliance (<20ml/cmH2O), 982 (63·2%) with low-normal compliance (20-50ml/cmH2O), and 34 (2·2%) with high lung compliance (>50ml/cmH2O). The very low compliance group had double the median time to intubation compared to the low-normal group (107 hours (IQR 26·3, 238·3) vs. 37·9 hours (IQR 4·8, 90·7)). Overall, 67·5% (n=1049) of the patients died during the hospitalization. In comparison to non-COVIDARDS reports, there were less patients in the high compliance category (2.2%vs.12%, compliance ≥50mL/cmH20), and more patients with P/F ≤ 150 (57·8% vs. 45.6%). No correlation was apparent between lung compliance and P/F ratio. The Oxygenation Index was similar, (11·12(SD 5·67) vs.12·8(SD 10·8)).1

Dysanapsis in men and women with obesity

Obesity alters chest wall mechanics, reduces lung volumes, and increases airway resistance. In addition, the luminal area of the larger conducting airways is smaller in women than in men when matched for lung size. We examined whether differences in pulmonary mechanics with obesity and sex were associated with the dysanapsis ratio (DR), an estimate of airway size when expiratory flow is maximal, in men and women with and without obesity. Additionally, we examined the ability to estimate DR using predicted versus measured static recoil pressure at 50%FVC (Pst50FVC). Participants completed pulmonary function testing and measurements of pulmonary mechanics. Flow, volume, and transpulmonary pressure were recorded while completing forced vital capacity (FVC) maneuvers in a body plethysmograph. Static compliance curves were collected using the occlusion technique. DR was calculated using measured values of forced mid-expiratory flow and Pst50FVC. DR was also calculated using Pst predicted from previously reported data. There was no significant group (lean vs. obese) by sex interaction or main effect of group on DR. However, women displayed significantly larger DR compared with men. Predicted Pst50FVC was significantly greater than measured Pst50FVC. DR calculated from measured Pst was significantly greater than when using predicted Pst. In conclusion, while obesity does not appear to alter airway size, women may have larger airways compared with men when mid-expiratory flow is maximal. Additionally, DR estimated using predicted Pst should be used with caution.