Effects of an open lung ventilatory strategy on lung gas exchange during laparoscopic surgery

In general anaesthesia, early collapse of poorly ventilated lung segments with low alveolar ventilation–perfusion ratios occurs and may lead to postoperative pulmonary complications after abdominal surgery. An ‘open lung’ ventilation strategy involves lung recruitment followed by ‘individualised’ positive end-expiratory pressure titrated to maintain recruitment of low alveolar ventilation–perfusion ratio lung segments. There are limited data in laparoscopic surgery on the effects of this on pulmonary gas exchange. Forty laparoscopic bowel surgery patients were randomly assigned to standard ventilation or an ‘open lung’ ventilation intervention, with end-tidal target sevoflurane of 1% supplemented by propofol infusion. After peritoneal insufflation, stepped lung recruitment was performed in the intervention group followed by maintenance positive end-expiratory pressure of 12–15 cmH2O adjusted to maintain dynamic lung compliance at post-recruitment levels. Baseline gas and blood samples were taken and repeated after a minimum of 30 minutes for oxygen and carbon dioxide and for sevoflurane partial pressures using headspace equilibration. The sevoflurane arterial/alveolar partial pressure ratio and alveolar deadspace fraction were unchanged from baseline and remained similar between groups (mean (standard deviation) control group = 0.754 (0.086) versus intervention group = 0.785 (0.099), P = 0.319), while the arterial oxygen partial pressure/fractional inspired oxygen concentration ratio was significantly higher in the intervention group at the second timepoint (control group median (interquartile range) 288 (234–372) versus 376 (297–470) mmHg in the intervention group, P = 0.011). There was no difference between groups in the sevoflurane consumption rate. The efficiency of sevoflurane uptake is not improved by open lung ventilation in laparoscopy, despite improved arterial oxygenation associated with effective and sustained recruitment of low alveolar ventilation–perfusion ratio lung segments.

Lung ultrasound guided pulmonary recruitment during mechanical ventilation in neonates: A case series

BACKGROUND: Recently, the first report of lung ultrasound (LUS) guided recruitment during open lung ventilation in neonates has been published. LUS guided recruitment can change the approach to open lung ventilation, which is currently performed without any measure of lung function/lung expansion in the neonatal population. METHODS: We included all the newborn infants that underwent a LUS-guided recruitment maneuver during mechanical ventilation as a rescue attempt for an extremely severe respiratory condition with oxygen saturation/fraction of inspired oxygen (SpO2/FIO2) ratio below 130 or the inability to wean off mechanical ventilation. RESULTS: We report a case series describing 4 LUS guided recruitment maneuvers, underlying crucial aspects of this technique that can improve the effectiveness of the procedure. In particular, we describe a novel pattern (the S-pattern) that allows us to distinguish the recruitable from the unrecruitable lung and guide the pressure titration phase. Additionally, we describe the optimal LUS-guided patient positioning. CONCLUSIONS: We believe that the inclusion of specifications regarding patient positioning and the S-pattern in the LUS-guided protocol may be beneficial for the success of the procedure.

Acute respiratory distress syndrome phenotypes with distinct clinical outcomes in PHARLA trial cohort

Background: The Permissive Hypercapnia, Alveolar Recruitment and Low Airway Pressure (PHARLAP) randomised controlled trial compared an open lung ventilation strategy with control ventilation, and found that open lung ventilation did not reduce the number of ventilator-free days (VFDs) or mortality in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Parsimonious models can identify distinct phenotypes of ARDS (hypo-inflammatory and hyperinflammatory) which are associated with different outcomes and treatment responses. Objective: To test the hypothesis that a parsimonious model would identify patients with distinctly different clinical outcomes in the PHARLAP study. Design, setting and participants: Blood and lung lavage samples were collected in a subset of PHARLAP patients who were recruited in Australian and New Zealand centres. A previously validated parsimonious model (interleukin-8, soluble tumour necrosis factor receptor-1 and bicarbonate) was used to classify patients with blood samples into hypo-inflammatory and hyperinflammatory groups. Generalised linear modelling was used to examine the interaction between inflammatory phenotype and treatment group (intervention or control). Main outcome measure: The primary outcome was number of VFDs at Day 28. Results: Data for the parsimonious model were available for 56 of 115 patients (49%). Within this subset, 38 patients (68%) and 18 patients (32%) were classified as having hypo-inflammatory and hyperinflammatory phenotypes, respectively. Patients with the hypo-inflammatory phenotype had more VFDs at Day 28 when compared with those with the hyperinflammatory phenotype (median [IQR], 19.5 [11–24] versus 8 [0–21]; P = 0.03). Patients with the hyperinflammatory phenotype had numerically fewer VFDs when managed with an open lung strategy than when managed with control “protective” ventilation (median [IQR], 0 [0–19] versus 16 [8–22]). Conclusion: In the PHARLAP trial, ARDS patients classified as having a hyperinflammatory phenotype, with a parsimonious three-variable model, had fewer VFDs at Day 28 compared with patients classified as having a hypo-inflammatory phenotype. Future clinical studies of ventilatory strategies should consider incorporating distinct ARDS phenotypes into their trial design.

Diffuse alveolar haemorrhage in the setting of eosinophilic pneumonia

A 65-year-old woman who presented with a constellation of symptoms, including cough with haemoptysis, fever, chills and hypoxia along with weight loss, was found to have diffuse alveolar haemorrhage. After a myriad of investigations returned normal, an open lung biopsy was performed, which revealed the diagnosis to be subacute eosinophilic pneumonia. This is one of its kind of rare presentations where eosinophilic pneumonia presents as diffuse alveolar haemorrhage and has been reported only five times prior to this.

The spectrum of congenital malformations of the lung at a rural

ABSTRACT Background: Congenital malformations of lung, such as congenital lobar emphysema, cystic adenomatoid malformation, bronchial cyst, pulmonary sequestration are of rare occurrence. However, our hospital being in a rural area attracts a large number of patients with complex malformations. Method: This retrospective analysis is done to evaluate diagnostic accuracy, safety and efficacy and outcomes of open lung resections at a rural hospital. Results: 16 children with congenital lung malformation underwent open resection in a rural hospital, with no mortality and minimal morbidity, no complications and more than 24 months follow-up. Conclusion: Open lung resections are found to be safe, effective in a rural setting also.

What Open-Lung Biopsy Teaches Us about ARDS in COVID-19 Patients: Mechanisms, Pathology, and Therapeutic Implications

Difficulties have risen while managing Acute Respiratory Distress Syndrome (ARDS) caused by COVID-19, although it meets the Berlin definition. Severe hypoxemia with near-normal compliance was noted along with coagulopathy. Understanding the precise pathophysiology of this atypical ARDS will assist researchers and physicians in improving their therapeutic approach. Previous work is limited to postmortem studies, while our report addresses patients under protective lung mechanical ventilation. An open-lung minithoracotomy was performed in 3 patients who developed ARDS related to COVID-19 and were admitted to the intensive care unit to carry out a pathological and microbiological analysis on lung tissue biopsy. Diffused alveolar damage with hyaline membranes was found, as well as plurifocal fibrin microthrombi and vascular congestion in all patients’ specimens. Microbiological cultures were negative, whereas qualitative Reversed Transcriptase Polymerase Chain Reaction (RT-PCR) detected SARS-CoV-2 in the pulmonary parenchyma and pleural fluid in two patients. COVID-19 causes progressive ARDS with onset of severe hypoxemia, underlying a dual mechanism: shunt effect through diffused alveolar damage and dead space effect through thrombotic injuries in microvascular beds. It seems reasonable to manage this ventilation-perfusion ratio mismatch using a high dose of anticoagulant combined with glucocorticoids.

High Frequency Oscillating Ventilation (HFOV) in Severe Acute Respiratory Distress Syndrome (ARDS): A Case Report

High frequency oscillating ventilation (HFOV) provides a rescue therapy for patients with refractory hypoxaemia in severe acute respiratory distress syndrome (ARDS). HFOV utilizes high mean airway pressures to maintain an open lung and low tidal volumes at a high frequency that allows for adequate ventilation while at the same time preventing alveolar overdistension. This seems to be an ideal lung protective ventilation strategies to prevent ventilator-induced lung injury (VILI)2. We reported a case of severe extrapulmonary ARDS secondary to acute lymphoblastic leukaemia responding to the use of HFOV.