Recruitment maneuver does not provide any mortality benefit over lung protective strategy ventilation in adult patients with acute respiratory distress syndrome: a meta-analysis and systematic review of the randomized controlled trials

Ventilation strategy during urological and gynaecological robotic-assisted surgery: a narrative review

Robotic-assisted surgery has improved the precision and accuracy of surgical movements with subsequent improved outcomes. However, it requires steep Trendelenburg positioning combined with pneumoperitoneum that negatively affects respiratory mechanics and increases the risk of postoperative respiratory complications. This narrative review summarises the state of the art in ventilatory management of these patients in terms of levels of positive end-expiratory pressure (PEEP), tidal volume, recruitment manoeuvres, and ventilation modes during both urological and gynaecological robotic-assisted surgery. A review of the literature was conducted using PubMed/MEDLINE; after completing abstract and full-text review, 31 articles were included. Although different levels of PEEP were often evaluated within a protective ventilation strategy, including higher levels of PEEP, lower tidal volume, and recruitment manoeuvres vs a conventional ventilation strategy, we conclude that the best PEEP in terms of lung mechanics, gas exchange, and ventilation distribution has not been defined, but moderate PEEP levels (4-8 cm H2O) could be associated with better outcomes than lower or highest levels. Recruitment manoeuvres improved intraoperative arterial oxygenation, end-expiratory lung volume and the distribution of ventilation to dependent (dorsal) lung regions. Pressure-controlled compared with volume-controlled ventilation showed lower peak airway pressures with both higher compliance and higher carbon dioxide clearance. We propose directions to optimise ventilatory management during robotic surgery in light of the current evidence.

Exploring pulmonary distribution of intratracheally instilled liquid foams in excised porcine lungs

The applicability of inhalation therapy to some severe pulmonary conditions is often compromised by limited delivery rates (i.e. total dose) and low deposition efficiencies in the respiratory tract, most notably in the deep pulmonary acinar airways. To circumvent such limitations, alternative therapeutic techniques have relied for instance on intratracheal liquid instillations for the delivery of high-dose therapies. Yet, a longstanding mechanistic challenge with such latter methods lies in delivering solutions homogeneously across the whole lungs, despite an inherent tendency of non-uniform spreading driven mainly by gravitational effects. Here, we hypothesize that the pulmonary distribution of instilled liquid solutions can be meaningfully improved by foaming the solution prior to its instillation, owing to the increased volume and the reduced gravitational bias of foams. As a proof-of-concept, we show in excised adult porcine lungs that liquid foams can lead to significant improvement in homogenous pulmonary distributions compared with traditional liquid instillations. Our ex-vivo results suggest that liquid foams can potentially offer an attractive novel pulmonary delivery modality with applications for high-dose regimens of respiratory therapeutics.

Management of refractory hypoxemia using recruitment maneuvers and rescue therapies: A comprehensive review

Refractory hypoxemia in patients with acute respiratory distress syndrome treated with mechanical ventilation is one of the most challenging conditions in human and veterinary intensive care units. When a conventional lung protective approach fails to restore adequate oxygenation to the patient, the use of recruitment maneuvers and positive end-expiratory pressure to maximize alveolar recruitment, improve gas exchange and respiratory mechanics, while reducing the risk of ventilator-induced lung injury has been suggested in people as the open lung approach. Although the proposed physiological rationale of opening and keeping open previously collapsed or obstructed airways is sound, the technique for doing so, as well as the potential benefits regarding patient outcome are highly controversial in light of recent randomized controlled trials. Moreover, a variety of alternative therapies that provide even less robust evidence have been investigated, including prone positioning, neuromuscular blockade, inhaled pulmonary vasodilators, extracorporeal membrane oxygenation, and unconventional ventilatory modes such as airway pressure release ventilation. With the exception of prone positioning, these modalities are limited by their own balance of risks and benefits, which can be significantly influenced by the practitioner's experience. This review explores the rationale, evidence, advantages and disadvantages of each of these therapies as well as available methods to identify suitable candidates for recruitment maneuvers, with a summary on their application in veterinary medicine. Undoubtedly, the heterogeneous and evolving nature of acute respiratory distress syndrome and individual lung phenotypes call for a personalized approach using new non-invasive bedside assessment tools, such as electrical impedance tomography, lung ultrasound, and the recruitment-to-inflation ratio to assess lung recruitability. Data available in human medicine provide valuable insights that could, and should, be used to improve the management of veterinary patients with severe respiratory failure with respect to their intrinsic anatomy and physiology.

A novel lung recruitment technique in pediatric patients with congenital heart diseases: A case series

Background

Lung recruitment techniques are employed to help in improvement of pulmonary mechanics, facilitate early weaning, and shorten the duration of mechanical ventilation. We are reporting a novel lung recruitment technique employed in four children with left lung atelectasis, who underwent corrective surgery for congenital heart disease.

Materials and Methods

From January 2020 to March 2021, four pediatric cardiac patients having left lung atelectasis, undergoing corrective surgery were subjected to lung recruitment technique and had elective endobronchial intubation and suctioning with chest physiotherapy in the form of vibration and percussion. This was done along with intermittent ventilation with 100% oxygen.

Results

Successful recruitment of lung segments and clearance of atelectasis were confirmed by auscultation and chest X-ray in all four patients. All the cases were successfully weaned off the ventilator within 24-48 h. One patient had an opposite lung collapse after extubation, which was managed conservatively with chest physiotherapy. Another patient had bradycardia and desaturation during the procedure, which was improved after withdrawing the tube and instituting two lung ventilation with 100% oxygen.

Conclusions

This novel lung recruitment technique helps in recruitment of collapsed lung segments and thus helps in early weaning and shortens the duration of mechanical ventilation.

Incidence and outcomes of acute respiratory distress syndrome in intensive care units of mainland China: a multicentre prospective longitudinal study

OBJECTIVES

To evaluate the incidence and mortality of acute respiratory distress syndrome (ARDS) in medical/respiratory intensive care units (MICUs/RICUs) to assess ventilation management and the use of adjunct therapy in routine clinical practice for patients fulfilling the Berlin definition of ARDS in mainland China.

METHODS

This was a multicentre prospective longitudinal study. Patients who met the Berlin definition of ARDS were included. Baseline data and data on ventilator management and the use of adjunct therapy were collected.

RESULTS

Of the 18,793 patients admitted to participating ICUs during the study timeframe, 672 patients fulfilled the Berlin ARDS criteria and 527 patients were included in the analysis. The most common predisposing factor for ARDS in 402 (77.0) patients was pneumonia. The prevalence rates were 9.7% (51/527) for mild ARDS, 47.4% (250/527) for moderate ARDS, and 42.9% (226/527) for severe ARDS. In total, 400 (75.9%) patients were managed with invasive mechanical ventilation during their ICU stays. All ARDS patients received a tidal volume of 6.8 (5.8-7.9) mL/kg of their predicted body weight and a positive end-expository pressure (PEEP) of 8 (6-12) cmH₂O. Recruitment manoeuvres (RMs) and prone positioning were used in 61 (15.3%) and 85 (16.1%) ventilated patients, respectively. Life-sustaining care was withdrawn from 92 (17.5%) patients. When these patients were included in the mortality analysis, 244 (46.3%) ARDS patients (16 (31.4%) with mild ARDS, 101 (40.4%) with moderate ARDS, and 127 (56.2%) with severe ARDS) died in the hospital.

CONCLUSIONS

Among the 18 ICUs in mainland China, the incidence of ARDS was low. The rates of mortality and withdrawal of life-sustaining care were high. The recommended lung protective strategy was followed with a high degree of compliance, but the implementation of adjunct treatment was lacking. These findings indicate the potential for improvement in the management of patients with ARDS in China.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02975908 . Registered on 29 November 2016-retrospectively registered.

A Physiologically Informed Strategy to Effectively Open, Stabilize, and Protect the Acutely Injured Lung

Acute respiratory distress syndrome (ARDS) causes a heterogeneous lung injury and remains a serious medical problem, with one of the only treatments being supportive care in the form of mechanical ventilation. It is very difficult, however, to mechanically ventilate the heterogeneously damaged lung without causing secondary ventilator-induced lung injury (VILI). The acutely injured lung becomes time and pressure dependent, meaning that it takes more time and pressure to open the lung, and it recollapses more quickly and at higher pressure. Current protective ventilation strategies, ARDSnet low tidal volume (LVt) and the open lung approach (OLA), have been unsuccessful at further reducing ARDS mortality. We postulate that this is because the LVt strategy is constrained to ventilating a lung with a heterogeneous mix of normal and focalized injured tissue, and the OLA, although designed to fully open and stabilize the lung, is often unsuccessful at doing so. In this review we analyzed the pathophysiology of ARDS that renders the lung susceptible to VILI. We also analyzed the alterations in alveolar and alveolar duct mechanics that occur in the acutely injured lung and discussed how these alterations are a key mechanism driving VILI. Our analysis suggests that the time component of each mechanical breath, at both inspiration and expiration, is critical to normalize alveolar mechanics and protect the lung from VILI. Animal studies and a meta-analysis have suggested that the time-controlled adaptive ventilation (TCAV) method, using the airway pressure release ventilation mode, eliminates the constraints of ventilating a lung with heterogeneous injury, since it is highly effective at opening and stabilizing the time- and pressure-dependent lung. In animal studies it has been shown that by “casting open” the acutely injured lung with TCAV we can (1) reestablish normal expiratory lung volume as assessed by direct observation of subpleural alveoli; (2) return normal parenchymal microanatomical structural support, known as alveolar interdependence and parenchymal tethering, as assessed by morphometric analysis of lung histology; (3) facilitate regeneration of normal surfactant function measured as increases in surfactant proteins A and B; and (4) significantly increase lung compliance, which reduces the pathologic impact of driving pressure and mechanical power at any given tidal volume.

Effect of lung recruitment maneuver on oxygenation, physiological parameters and mortality in acute respiratory distress syndrome patients: a systematic review and meta-analysis

PURPOSE

Among acute respiratory distress syndrome (ARDS) patients in intensive care units, the efficacy of lung recruitment maneuver (LRM) use is uncertain taking into account the most recent randomized controlled trials (RCTs). We aimed to estimate the effect of LRMs on mortality from ARDS.

METHODS

In this systematic review and meta-analysis, we searched for RCTs comparing mechanical ventilation with and without LRMs in adults with ARDS. We generated pooled relative risks (RR), mean difference, performed trial-sequential-analysis and cumulative meta-analysis. The primary outcome was 28-day mortality. The secondary outcomes were oxygenation evaluated by PaO₂/FiO₂ ratio, rate of rescue therapy and rate of hemodynamic compromise.

RESULTS

In 14 RCTs including 3185 patients, LRMs were not associated with reduced 28-day mortality (RR = 0.92, 95% confidence interval (95% CI) 0.82-1.04, P = 0.21), compared to no-LRM. Trial-sequential-analysis showed that the required information size has been accrued. PaO₂/FiO₂ ratio was significantly higher in the LRMs group in comparison to the no-LRM group (mean difference = 47.6 mmHg, 95% CI 33.4-61.8, P < 0.001). LRMs were associated with a decreased rate of rescue therapy (RR = 0.69 95% CI 0.56-0.84, P < 0.001), and an increased rate of hemodynamic compromise (RR = 1.19, 95% CI 1.06-1.33, P = 0.002), compared to no-LRM group. Using cumulative meta-analysis, a significant change for effect on mortality was observed after 2017.

CONCLUSIONS

The results suggest that in ARDS patients, systematic use of LRMs does not significantly improve 28-day mortality. However, LRM use was associated with positive effects such as an oxygenation improvement and a less frequent use of rescue therapy. Nevertheless, LRM use was associated with negative effects such as hemodynamic impairment.