Summary
The effect of intra‐operative mechanical ventilation modes on pulmonary outcomes after thoracic surgery with one‐lung ventilation has not been well established. We evaluated the impact of ...three common ventilation modes on postoperative pulmonary complications in patients undergoing lung resection surgery. In this two‐centre randomised controlled trial, 1224 adults scheduled for lung resection surgery with one‐lung ventilation were randomised to one of three groups: volume‐controlled ventilation; pressure‐controlled ventilation; and pressure‐control with volume guaranteed ventilation. Enhanced recovery after surgery pathways and lung‐protective ventilation protocols were implemented in all groups. The primary outcome was a composite of postoperative pulmonary complications within the first seven postoperative days. The outcome occurred in 270 (22%), with 87 (21%) in the volume control group, 89 (22%) in the pressure control group and 94 (23%) in the pressure‐control with volume guaranteed group (p = 0.831). The secondary outcomes also did not differ across study groups. In patients undergoing lung resection surgery with one‐lung ventilation, the choice of ventilation mode did not influence the risk of developing postoperative pulmonary complications. This is the first randomised controlled trial examining the effect of three ventilation modes on pulmonary outcomes in patients undergoing lung resection surgery.
Objective: Lung injury can develop in the perioperative period due to ventilation management techniques. Thus, the attitude of anaesthetists on protective ventilation (PV) practice comes into ...question. In our study, we aimed to evaluate the perioperative ventilation practice of anaesthetists and trainees on anaesthesiology by a survey study. Methods: Survey form was sent to all doctors registered to TARD via electronic mail. The participants were asked questions involving PV parameters such as low tidal volume (TV) according to ideal body weight (BW), positive end-expiratory pressure (PEEP), FiO2 use and recruitment manoeuvre (RM) application. In total, 411 doctors who answered the survey were included to the study. Application rates of PV parameters and causes were compared within the answers obtained. P<0.05 was accepted statistically significant. Results: PV was practised by 19.4% of the participants. Those who preferred low TV used ideal BW more frequently (p<0.001). PEEP of 4-6 cm H2O was commonly used (p<0.001). The participants mostly preferred FiO2 of 1.0 (60.4%), and application rate of RM was found to be 17.2%. The use of all PV parameters was detected to be higher among instructors than among other groups. Conclusion: In our study, application ratio of PV with all its parameters was found to be lower. Among the parameters, while low TV according to ideal BW and PEEP were applied at higher ratios, the use of RM and low oxygen percentage were applied less frequently. While PV was found to be useful in terms of perioperative ventilation strategies, low practice rates may result from habits besides lack of knowledge and experience; comprehensive and quality education studies are needed to overcome this.
Objective
We aimed to explore whether noninvasive high‐frequency oscillatory ventilation (NHFOV) could reduce the incidence of reintubation compared with nasal intermittent positive pressure ...ventilation (NIPPV) in the postextubation phase of preterm infants.
Methods
Randomized controlled trials of NHFOV versus NIPPV were searched in PubMed, EMBASE, Cochrane Central, and MEDLINE. Meta‐analysis was performed using Review Manager 5.3.
Results
Four randomized controlled trials including 1138 preterm infants were included in this study. Compared with NIPPV, NHFOV reduced the incidence of reintubation in the post‐extubation phase of preterm infants (p = 0.01, RR = 0.72, 95% confidence interval (CI): 0.56∼0.94), and no heterogeneity was found in the four studies (p = 0.55, I2 = 0%). In the sensitivity analysis, the result showed that there was no significant difference in the incidence of reintubation between NHFOV and NIPPV after excluding one study (p = 0. 05, RR = 0.76 95% CI: 0.58∼1.00), and no heterogeneity was found in the other three studies (p = 0.95, I2 = 0%). There was no statistical difference between NHFOV and NIPPV in BPD, air leak, IVH (≥Grade III) and mortality.
Conclusion
Among mechanically ventilated preterm infants, compared with NIPPV, NHFOV was potentially beneficial to reduce the incidence of reintubation after extubation and did not increase the risk of complications.
Damage caused by lung overdistension (volutrauma) has been implicated in the development of bronchopulmonary dysplasia (BPD). Modern neonatal ventilation modes can target a set tidal volume as an ...alternative to traditional pressure-limited ventilation (PLV) using a fixed inflation pressure. Volume-targeted ventilation (VTV) aims to produce a more stable tidal volume in order to reduce lung damage and stabilise the partial pressure of carbon dioxide (pCO
).
To determine whether VTV compared with PLV leads to reduced rates of death and death or BPD in newborn infants and to determine whether use of VTV affected outcomes including air leak, cranial ultrasound findings and neurodevelopment.
We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 12), MEDLINE via PubMed (1966 to 13 January 2017), Embase (1980 to 13 January 2017) and CINAHL (1982 to 13 January 2017). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We contacted the principal investigators of studies to obtain supplementary information.
Randomised and quasi-randomised trials comparing VTV versus PLV in infants of less than 44 weeks' postmenstrual age and reporting clinically relevant outcomes.
We assessed risk of bias for each trial using Cochrane methodology. We evaluated quality of evidence for each outcome using GRADE criteria. We tabulated mortality, rates of BPD, short-term clinical outcomes and long-term developmental outcomes.
for categorical outcomes, we calculated typical estimates for risk ratios (RR), risk differences (RD) and number needed to treat for an additional beneficial outcome (NNTB). For continuous variables, we calculated typical estimates for mean differences (MD). We used 95% confidence intervals (CI) and assumed a fixed-effect model for meta-analysis.
Twenty randomised trials met our inclusion criteria; 16 parallel trials (977 infants) and four cross-over trials (88 infants). No studies were blinded and the quality of evidence for outcomes assessed varied from moderate to low.We found no difference in the primary outcome, death before hospital discharge, between VTV modes versus PLV modes (typical RR 0.75, 95% CI 0.53 to 1.07; low quality evidence). However, there was moderate quality evidence that the use of VTV modes resulted in a reduction in the primary outcome, death or BPD at 36 weeks' gestation (typical RR 0.73, 95% CI 0.59 to 0.89; typical NNTB 8, 95% CI 5 to 20) and the following secondary outcomes: rates of pneumothorax (typical RR 0.52, 95% CI 0.31 to 0.87; typical NNTB 20, 95% CI 11 to 100), mean days of mechanical ventilation (MD -1.35 days, 95% CI -1.83 to -0.86), rates of hypocarbia (typical RR 0.49, 95% CI 0.33 to 0.72; typical NNTB 3, 95% CI 2 to 5), rates of grade 3 or 4 intraventricular haemorrhage (typical RR 0.53, 95% CI 0.37 to 0.77; typical NNTB 11, 95% CI 7 to 25) and the combined outcome of periventricular leukomalacia with or without grade 3 or 4 intraventricular haemorrhage (typical RR 0.47, 95% CI 0.27 to 0.80; typical NNTB 11, 95% CI 7 to 33). VTV modes were not associated with any increased adverse outcomes.
Infants ventilated using VTV modes had reduced rates of death or BPD, pneumothoraces, hypocarbia, severe cranial ultrasound pathologies and duration of ventilation compared with infants ventilated using PLV modes. Further studies are needed to identify whether VTV modes improve neurodevelopmental outcomes and to compare and refine VTV strategies.
Thoroughly revised, this book provides the reader with an understanding of the principles and practices of testing and balancing (TAB) heating, ventilating, and air conditioning (HVAC) air and water ...systems. For the novice and the experienced testing and balancing technician, it is a field reference book of procedures, equations, and information tables.
Divided into five parts, Part I has general and specific balancing procedures for constant air volume systems, variable air volume systems, return air systems, and fans and fan performance. Part II covers testing and balancing fume hood systems and cleanrooms, commissioning HVAC systems, centrifugal pumps and pump performance, analog and digital controls and water balancing procedures using flow meters, system components, and temperatures. Part III covers fans, pumps, air distribution, water distribution, motors, electrical, fluid flow, psychrometrics, refrigeration, and instrument usage and care. Part IV includes equations and tables. New to this edition, Part V has information and additional test and balance procedures and graphics for chapters 1-7 and 13-14. TAB Data and Test forms are in the new addendum as well.
Provides the readers with revised information about the principles and practices of testing and balancing (TAB) heating
Represents a field reference guide for both the novice and experienced testing and balancing technician
Includes a new section with information and additional test and balance procedures and graphics
The role of non-invasive respiratory support (high-flow nasal oxygen and noninvasive ventilation) in the management of acute hypoxemic respiratory failure and acute respiratory distress syndrome is ...debated. The oxygenation improvement coupled with lung and diaphragm protection produced by non-invasive support may help to avoid endotracheal intubation, which prevents the complications of sedation and invasive mechanical ventilation. However, spontaneous breathing in patients with lung injury carries the risk that vigorous inspiratory effort, combined or not with mechanical increases in inspiratory airway pressure, produces high transpulmonary pressure swings and local lung overstretch. This ultimately results in additional lung damage (patient self-inflicted lung injury), so that patients intubated after a trial of noninvasive support are burdened by increased mortality. Reducing inspiratory effort by high-flow nasal oxygen or delivery of sustained positive end-expiratory pressure through the helmet interface may reduce these risks. In this physiology-to-bedside review, we provide an updated overview about the role of noninvasive respiratory support strategies as early treatment of hypoxemic respiratory failure in the intensive care unit. Noninvasive strategies appear safe and effective in mild-to-moderate hypoxemia (PaO
2
/FiO
2
> 150 mmHg), while they can yield delayed intubation with increased mortality in a significant proportion of moderate-to-severe (PaO
2
/FiO
2
≤ 150 mmHg) cases. High-flow nasal oxygen and helmet noninvasive ventilation represent the most promising techniques for first-line treatment of severe patients. However, no conclusive evidence allows to recommend a single approach over the others in case of moderate-to-severe hypoxemia. During any treatment, strict physiological monitoring remains of paramount importance to promptly detect the need for endotracheal intubation and not delay protective ventilation.
Lung-Kidney Cross-Talk in the Critically Ill Patient Husain-Syed, Faeq; Slutsky, Arthur S; Ronco, Claudio
American journal of respiratory and critical care medicine,
08/2016, Volume:
194, Issue:
4
Journal Article
Peer reviewed
Discoveries have emerged highlighting the complex nature of the interorgan cross-talk between the kidney and the lung. Vascular rigidity, neurohormonal activation, tissue hypoxia, and abnormal immune ...cell signaling have been identified as common pathways leading to the development and progression of chronic kidney disease. However, our understanding of the causal relationships between lung injury and kidney injury is not precise. This review discusses a number of features and mechanisms of renal dysfunction in pulmonary disorders in relation to respiratory acidosis, impaired gas exchange, systemic congestion, respiratory support/replacement therapies, and other issues relevant to the clinical care of these patients. Biotrauma due to injurious ventilatory strategies can lead to the release of mediators into the lung, which may then translocate into the systemic circulation and cause end-organ dysfunction, including renal dysfunction. Right ventricular dysfunction and congestive states may contribute to alterations of renal perfusion and oxygenation, leading to diuretic resistance and recurrent hospitalization. In patients with concomitant respiratory failure, noninvasive ventilation represents a promising treatment option for the correction of impaired renal microcirculation and endothelial dysfunction. In patients requiring extracorporeal membrane oxygenation, short- and long-term monitoring of kidney function is warranted, as they are at highest risk of developing acute kidney injury and fluid overload.
Noninvasive ventilation (NIV) has a number of physiologic effects similar to invasive ventilation. The major effects are to augment minute ventilation and reduce muscle loading. These effects, in ...turn, can have profound effects on the patient's ventilator control system, both acutely and chronically. Because NIV can be supplied with PEEP, the maintenance of alveolar recruitment is also made possible and the triggering load imposed by auto-PEEP can be reduced. NIV (or simply mask CPAP) can maintain upper-airway patency during sleep in patients with obstructive sleep apnea. NIV can have multiple effects on cardiac function. By reducing venous return, it can help in patients with heart failure or fluid overload, but it can compromise cardiac output in others. NIV can also increase right ventricular afterload or function to reduce left ventricular afterload. Potential detrimental physiologic effects of NIV are ventilator-induced lung injury, auto-PEEP development, and discomfort/muscle overload from poor patient-ventilator interactions.
Background
The population of children with chronic respiratory failure requiring long‐term mechanical ventilation in the home has grown worldwide. The optimal choice from an increasing number of home ...ventilators commercialized for children is often challenging for the attending physicians. The aim of the present study was to compare the trigger performance of five pediatric bilevel home ventilators and one intensive care unit ventilator depending on circuit type and system leak.
Methods
The trigger performances of the ventilators were compared in combination with all compatible circuits using a physical model of the lung with increasing system leak. The flow generator simulated the patient's breathing effort with flow rates of 2.7–6.4 L/min at a frequency of 30 breaths/min. All ventilators were set to deliver 16 cmH2O inspiratory pressure support and 4 cmH2O positive end‐expiratory pressure.
Results
Trigger thresholds varied from 1.5 to 8 L/min, the pressure rise time to 90% of the maximum from 140 to 385 ms and the trigger work from 0.5 to 6.6 mbar · s. All devices had very short trigger delays below 40 ms. The leak compensation depended on the circuit type. The internal diameter of the circuit had no relevant impact on the trigger performance or the leak compensation.
Conclusion
We observed considerable differences in the triggering performance of the evaluated home ventilators depending on leak size and type of circuit. Therefore, an optimal combination of device and circuit should consider the patient's age and condition and the probability of system leak.
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