Effect of Intraoperative Ventilation Strategies on Postoperative Pulmonary Complications: A Meta-Analysis

Introduction: The role of intraoperative ventilation strategies in subjects undergoing surgery is still contested. This meta-analysis study was performed to assess the relationship between the low tidal volumes strategy and conventional mechanical ventilation in subjects undergoing surgery.Methods: A systematic literature search up to December 2020 was performed in OVID, Embase, Cochrane Library, PubMed, and Google scholar, and 28 studies including 11,846 subjects undergoing surgery at baseline and reporting a total of 2,638 receiving the low tidal volumes strategy and 3,632 receiving conventional mechanical ventilation, were found recording relationships between low tidal volumes strategy and conventional mechanical ventilation in subjects undergoing surgery. Odds ratio (OR) or mean difference (MD) with 95% confidence intervals (CIs) were calculated between the low tidal volumes strategy vs. conventional mechanical ventilation using dichotomous and continuous methods with a random or fixed-effect model.Results: The low tidal volumes strategy during surgery was significantly related to a lower rate of postoperative pulmonary complications (OR, 0.60; 95% CI, 0.44–0.83, p < 0.001), aspiration pneumonitis (OR, 0.63; 95% CI, 0.46–0.86, p < 0.001), and pleural effusion (OR, 0.72; 95% CI, 0.56–0.92, p < 0.001) compared to conventional mechanical ventilation. However, the low tidal volumes strategy during surgery was not significantly correlated with length of hospital stay (MD, −0.48; 95% CI, −0.99–0.02, p = 0.06), short-term mortality (OR, 0.88; 95% CI, 0.70–1.10, p = 0.25), atelectasis (OR, 0.76; 95% CI, 0.57–1.01, p = 0.06), acute respiratory distress (OR, 1.06; 95% CI, 0.67–1.66, p = 0.81), pneumothorax (OR, 1.37; 95% CI, 0.88–2.15, p = 0.17), pulmonary edema (OR, 0.70; 95% CI, 0.38–1.26, p = 0.23), and pulmonary embolism (OR, 0.65; 95% CI, 0.26–1.60, p = 0.35) compared to conventional mechanical ventilation.Conclusions: The low tidal volumes strategy during surgery may have an independent relationship with lower postoperative pulmonary complications, aspiration pneumonitis, and pleural effusion compared to conventional mechanical ventilation. This relationship encouraged us to recommend the low tidal volumes strategy during surgery to avoid any possible complications.

Case Series: The Coexistence of Thrombocytopenia and Thromboembolism in COVID-19 Patients on ECMO: A Case Series and Literature Review

Thrombocytopenia and thromboembolism are common complications in coronavirus disease 2019 (COVID-19) patients. The fact that COVID-19 patients develop both thrombocytopenia and thromboembolism has been observed, and multiple studies have investigated the underlying pathophysiology. Extracorporeal membrane oxygenation (ECMO) is reserved for COVID-19 patients who develop respiratory failure and not respond to conventional mechanical ventilation. ECMO induces thromboembolism and raises the incidence of developing thromboembolic events in COVID-19 patients. Here, we report the hospital courses and outcomes of three COVID-19 patients who were treated with ECMO, then developed both thrombocytopenia and thromboembolism. The coexistence of thrombocytopenia and thromboembolism challenges the clinical treatment strategy, including the decision of initiating anticoagulation. Based on current data, anticoagulation is recommended to all hospitalized COVID-19 patients unless there is active bleeding, previous bleeding history within 3 days, or platelet count is lower than 30,000 cells/μl. Further investigation into the mechanisms and implications of thrombocytopenia and thromboembolism in patients with COVID-19 pneumonia will lead to significantly improved outcomes and prognosis for the patients.

Closed-Loop Versus Conventional Mechanical Ventilation in COVID-19 ARDS

Background: Lung-protective ventilation is key in bridging patients suffering from COVID-19 acute respiratory distress syndrome (ARDS) to recovery. However, resource and personnel limitations during pandemics complicate the implementation of lung-protective protocols. Automated ventilation modes may prove decisive in these settings enabling higher degrees of lung-protective ventilation than conventional modes. Method: Prospective study at a Swiss university hospital. Critically ill, mechanically ventilated COVID-19 ARDS patients were allocated, by study-blinded coordinating staff, to either closed-loop or conventional mechanical ventilation, based on mechanical ventilator availability. Primary outcome was the overall achieved percentage of lung-protective ventilation in closed-loop versus conventional mechanical ventilation, assessed minute-by-minute, during the initial 7 days and overall mechanical ventilation time. Lung-protective ventilation was defined as the combined target of tidal volume <8 ml per kg of ideal body weight, dynamic driving pressure <15 cmH2O, peak pressure <30 cmH2O, peripheral oxygen saturation ≥88% and dynamic mechanical power <17 J/min. Results: Forty COVID-19 ARDS patients, accounting for 1,048,630 minutes (728 days) of cumulative mechanical ventilation, allocated to either closed-loop (n = 23) or conventional ventilation (n = 17), presenting with a median paO2/ FiO2 ratio of 92 [72-147] mmHg and a static compliance of 18 [11-25] ml/cmH2O, were mechanically ventilated for 11 [4-25] days and had a 28-day mortality rate of 20%. During the initial 7 days of mechanical ventilation, patients in the closed-loop group were ventilated lung-protectively for 65% of the time versus 38% in the conventional group (Odds Ratio, 1.79; 95% CI, 1.76-1.82; P < 0.001) and for 45% versus 33% of overall mechanical ventilation time (Odds Ratio, 1.22; 95% CI, 1.21-1.23; P < 0.001). Conclusion: Among critically ill, mechanically ventilated COVID-19 ARDS patients during an early highpoint of the pandemic, mechanical ventilation using a closed-loop mode was associated with a higher degree of lung-protective ventilation than was conventional mechanical ventilation.

Mobilization readiness to respiratory disasters: how to increase financial and economic availability of mechanical ventilation equipment

The COVID-19 pandemic demonstrated the critical vulnerability of modern society to the risk of respiratory disasters &ndash; situations of mass destruction of people by biological, chemical or radioactive agents with the development of respiratory failure that requires mechanical ventilation. This is substantiated by extremely high cost of conventional mechanical ventilation technology, which currently has no alternative, and implies &ldquo;anti-physiological&rdquo; (dangerous to health) pressure-targeted ventilation. Due to high cost of such equipment, no country is currently able to provide substantial mobilization reserves of ventilators, which in case of respiratory disasters, entails high mortality rate among population. The solution of this problem, the authors see the &ldquo;catching-up&rdquo; development of inexpensive, easy to use, and relatively safe method of mechanical ventilation with negative pressure ( the so-called tank ventilator or &ldquo;iron lungs&rdquo;), which encloses most of a person's body, and varies the air pressure in the enclosed space, to stimulate breathing. Due to the lower price, safety and ease of use of this method, the authors consider it essential in the instance of mass victims with respiratory failure caused by infectious, chemical or radiation agents. The conclusion is made on the importance of advancement of the mechanical ventilation technology based on the method of negative pressure for ensuring mobilization readiness of the Russian Federation to respiratory disaster, as well as the current need of the healthcare system.

Rest ventilator management in children on veno-venous extracorporeal membrane oxygenation

Background: We aimed to use the Extracorporeal Life Support Organization registry to describe the current practice of rest mechanical ventilation setting in children receiving veno-venous extracorporeal membrane oxygenation (V-V ECMO) and to determine if relationships exist between ventilator settings and mortality. Methods: Data for patients 14 days to 18 years old who received V-V ECMO from 2012-2016 were reviewed. Mechanical ventilation data available includes mode and settings at 24 h after ECMO cannulation. Multivariable logistic regression analysis was performed to determine if rest settings were associated with mortality. Results: We reviewed 1161 subjects, of which 1022 (88%) received conventional mechanical ventilation on ECMO. Rest settings, expressed as medians (25th%, 75th%), are as follows: rate 12 breaths/minute (10, 17); peak inspiratory pressure (PIP) 22 cmH2O (20,27); positive end expiratory pressure (PEEP) 10 cmH2O (8, 10); and fraction of inspired oxygen (FiO2) 0.4 (0.37, 0.60). Survival to discharge was 68%. Higher ventilator FiO2 (odds ratio:1.13 per 0.1 increase, 95% confidence interval:1.04, 1.23), independent of arterial oxygen saturation, was associated with mortality. Conclusions: Current rest ventilator management for children receiving V-V ECMO primarily relies on conventional mechanical ventilation with moderate amounts of PIP, PEEP, and FiO2. Further study on the relationship between FiO2 and mortality should be pursued.

HIGH-FREQUENCY ARTIFICIAL LUNG VENTILATION IN PREMATURE INFANTS WITH RESPIRATORY DISTRESS SYNDROME IN THE DELIVERY ROOM

Objective of the research: comparison of two methods of initial respiratory support: high-frequency positive pressure ventilation (HFPPV) and conventional mechanical ventilation (CMV) in extremely low birth weight (ELBW) infants. Materials and methods: prospective, randomized, pilot study, carried out in one level III perinatal center. Thirty-two ELBW babies was randomly separated in two groups: group A – HFPPV (n=17), group B – CMV (n=15). Results: the recovery time for heart rate more than 100 beats per minute in group A was faster than in group B (33,9 seconds vs. 79,2 seconds, p=0,002). Maximum FiO2 for the period of staying in hospital was significantly higher in group B (0,37 vs. 0,73, p<0,001). Mortality in CMV group was significantly higher (0% versus 27%, p=0,038). Conclusion: HFPPV in the delivery room in ELBW babies effectively restores heart rate, reduces the risk of lungs injury and the risk of death before discharge from the hospital.

Evaluation of Inhaled Nitric Oxide Use in Patients with Pediatric Acute Respiratory Distress Syndrome

Objective: Nitric oxide therapy is not routinely used in the treatment of pediatric acute respiratory distress syndrome (PARDS), but it is recommended to be used as an adjunctive therapy in some selected cases. In our study, we aimed to discuss patients with PARDS who were treated with inhaled nitric oxide (iNO) therapy. Methods: The data of patients who were hospitalized in the pediatric intensive care unit with a diagnosis of PARDS and received iNO treatment between January 2016 and January 2018 were retrospectively analyzed. Age, gender, length of stay, mortality, number of days on mechanical ventilation, use of vasoactive drugs, mortality scores, lactate levels, OI (oxygenation index), PaO2/FiO2, methemoglobin levels, iNO administration time, echocardiographic findings and underlying primary diseases were recorded. Results: It was determined that 9 patients who were followed up with the diagnosis of PARDS were given iNO treatment. Except for one patient, they were diagnosed with pneumonia developing on the basis of chronic disease and PARDS secondary to septic shock. Five patients died while receiving iNO therapy. Seven patients were ventilated with iNO in addition to conventional mechanical ventilation methods. Two patients who died were ventilated with HFOV (high frequency oscillatory ventilation). In 3 of 9 patients, inhaled nitric oxide treatment was successful. Conclusion: Although inhaled nitric oxide treatment is a known treatment used in different diseases, the level of its effect in PARDS patients continues to be investigated. We think that this treatment can be beneficial when applied in selected patients and experienced centers.