Lung Size Mismatch in Bilateral Lung Transplantation Is Associated With Allograft Function and Bronchiolitis Obliterans Syndrome

BACKGROUND:
Size mismatch between donor lungs and a recipient thorax could affect the major determinants of maximal expiratory airflow: airway resistance, propensity of airways to collapse, and lung elastic recoil. METHODS:
A retrospective review of 159 adults who received bilateral lung transplants was performed. The predicted total lung capacity (pTLC) for donors and recipients was calculated based on sex and height. Size matching was represented using the following formula: pTLC ratio = donor pTLC / recipient pTLC. Patients were grouped according to those with a pTLC ratio > 1.0 (oversized) or those with a pTLC ratio ≤ 1.0 (undersized). Allograft function was analyzed in relation to the pTLC ratio and to recipient and donor predicted function. RESULTS:
The 96 patients in the oversized cohort had a mean pTLC ratio of 1.16 ± 0.13 vs 0.89 ± 0.09 in the 63 patients of the undersized group. At 1 to 6 months posttransplant, the patients in the oversized cohort had higher FEV(1)/FVC ratios (0.895 ± 0.13 vs 0.821 ± 0.13, P < .01) and lower time constant estimates of lung emptying (0.38 ± 0.2 vs 0.64 ± 0.4, P < .01) than patients in the undersized cohort. Although the FVCs expressed as % predicted for the recipient were not different between cohorts, the FVCs expressed as % predicted for the donor organ were lower in the oversized cohort compared with the undersized cohort (at 1-6 months, 52.4% ± 17.1% vs 65.3% ± 18.3%, P < .001). Kaplan-Meier estimates for the occurrence of bronchiolitis obliterans syndrome...

Pulmonary Complications of Lung Transplantation

Lung transplantation is an effective treatment option for select patients with a variety of end-stage lung diseases. Although transplant can significantly improve the quality of life and prolong survival, a myriad of pulmonary complications may result in significant morbidity and limit long-term survival. The recognition and early treatment of these complications is important for optimizing outcomes. This article provides an overview and update of the pulmonary complications that may be commonly encountered by pulmonologists caring for these patients. …

Parenchymal trafficking of pleural mesothelial cells in idiopathic pulmonary fibrosis.

Abstract
Idiopathic pulmonary fibrosis (IPF) is characterised by myofibroblast proliferation leading to architectural destruction. Neither the origin nor the continued proliferation of myofibroblasts is well understood. Explanted human IPF lungs were stained by immunohistochemistry for calretinin, a marker of pleural mesothelial cells (PMCs). Chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF) lungs acted as controls. The number of PMCs per 100 nucleated cells and per photomicrograph was estimated along with the Ashcroft score of fibrosis. Mouse PMCs expressing green fluorescent protein (GFP) or labelled with nanoparticles were injected into the pleural space of mice given intranasal transforming growth factor (TGF)-β1. Mouse lungs were lavaged and examined for the presence of GFP, smooth muscle α-actin (α-SMA) and calretinin. Calretinin-positive PMCs were found throughout IPF lungs, but not in COPD or CF lungs. The number of PMCs correlated with the Ashcroft score. In mice, nanoparticle-laden PMCs were recoverable by bronchoalveolar lavage, depending on the TGF-β1 dose. Fluorescent staining showed α-SMA expression in GFP-expressing PMCs, with co-localisation of GFP and α-SMA. PMCs can traffic through the lung and show myofibroblast phenotypic markers. PMCs are present in IPF lungs, and their number correlates with IPF severity. Since IPF presumably begins subpleurally, PMCs could play a pathogenetic role via mesothelial-mesenchymal transition …

Pulmonary Hypertension secondary to Interstitial Lung Disease

Interstitial lung diseases (ILDs) may be complicated by the development of pulmonary hypertension (PH), which is associated with worse functional impairment and a poorer prognosis. This article reviews the current state of knowledge on the prevalence, pathogenesis, diagnosis and prognosis of ILD-related PH. Whether the treatment of ILD-related PH changes clinical outcomes is currently unknown, but the current studies are summarized and the authors’ perspective is offered. …

Tracheostomy in Ventilator-associated Pneumonia: Is it Preventive?

Tracheostomy is considered as a strategy that may improve respiratory mechanics and patient comfort and help in the management of secretions and weaning. Tracheostomy has also been suggested as a measure to decrease the risk of development of ventilator-associated pneumonia (VAP), compared with translaryngeal intubation. However, it has not been established whether tracheostomy is an effective strategy for VAP prevention. Data from observational and randomized trials found conflicting results on the relationship between tracheostomy and VAP. A recent large randomized, multicenter, well-designed and conducted study failed to demonstrate a significant reduction in VAP rate in patients who received early compared with late tracheostomy. Physicians’ attitudes regarding tracheostomy may be heterogeneous across different intensive care units and the decision to perform tracheostomy is still challenging. In the present article, we therefore aimed to determine the relationship between VAP and tracheostomy, and whether available data suggest that tracheostomy can prevent the occurrence of VAP. …

Phenol Spray Induced Methemoglobinemia

Background Topical anesthetics are commonly used in surgical patients during a variety of inpatient and outpatient procedures. On the surgical floor, they are also commonly used to relieve discomfort from the nasogastric tube in patients with bowel obstruction or ileus. We describe a case of severe methemoglobinemia due to the overuse of phenol (Chloraseptic) spray. Methods Sixty six-year-old man was being treated for ileus after an uneventful open abdominal aortic aneurysm repair. A nasogastric tube was inserted and phenol spray was given for discomfort. The patient developed respiratory distress and showed signs and symptoms of methemoglobinemia such as cyanosis, chocolate colored blood, and persistently low O2 saturation with normal arterial oxygenation. Results Methemoglobin level was elevated and methemoglobinemia was diagnosed. Methylene blue was administered intravenously and the patient recovered immediately with return to normal methemoglobin level. Conclusions Although phenol spray is used in patients with little or no side effect, a rare life-threatening complication can occur from its overuse: methemoglobinemia. Early recognition and prompt treatment of this condition are critical. …

The Effects of Neuromuscular-Blocking Agents on Gas Exchange in Patients With Acute Respiratory Distress Syndrome

Abstract: The use of neuromuscular-blocking agents (NMBA) in ventilated patients with acute respiratory distress syndrome (ARDS) is controversial and largely empiric. Few trials looked at their effectiveness on gas exchange or in improving lung mechanics in patients with ARDS. Only one randomized, controlled trial compared the effects of NMBA on gas exchange in patients with ARDS receiving NMBA as compared with patients receiving placebo throughout a period of 48 hours. In this trial, the early use of NMBA in patients with ARDS was associated with a sustained improvement in oxygenation. The muscular paralysis induced by NMBA could reduce the consumption of oxygen linked to the work of breathing. Muscular paralysis could facilitate mechanical ventilation by preventing spontaneous breaths responsible for the dys-synchrony and worsening of gas exchange. Muscular paralysis could increase compliance of the thoracic wall and improve mechanical ventilation during ARDS. However, these hypotheses are controversial. Finally, preliminary data show that the muscular paralysis could provide better adaptation to mechanical ventilation and better satisfaction with the protective criteria for reduction of ventilator-associated lung injuries by homogenizing the distribution of tidal volume and positive end expiratory pressure. The role of new NMBA (benzylisoquinolines) in the occurrence of critical illness neuromyopathy is largely questioned in the recent literature. It is important to design new studies to explain the mechanisms of the improvement in oxygenation associated with NMBA and to evaluate whether the use of NMBA modifies the outcome of patients with ARDS. …

Pulmonary Manifestations of Primary Autoimmune Hepatobiliary Disease

Abstract: The autoimmune hepatobiliary diseases are associated with a variety of pulmonary manifestations. There is increasing evidence of autoimmune pathophysiology occurring within the hepatopulmonary axis that may lead to clinically evident disease. Primary biliary cirrhosis (PBC) figures prominently among the primary autoimmune hepatobiliary processes with pulmonary involvement. PBC has been associated with subclinical alveolitis, sarcoidosis, bronchiolitis obliterans with organizing pneumonia, and lymphoid interstitial pneumonia, among others. Clinical associations have also been made between primary sclerosing cholangitis (PSC) and sarcoidosis, pulmonary fibrosis, or alveolar hemorrhage. Last, an evaluation of the current diagnostic criteria of autoimmune hepatitis has led to a reconsideration of its association with pulmonary fibrosis. Through a heightened clinical suspicion for these potential relationships, an improvement can be made in our comprehension of these autoimmune hepatobiliary processes and their impact on pulmonary physiology. …

Nutritional Support in Severe Sepsis

Nutritional support in severe sepsis remains a controversial issue. Although it has not been proven yet that nutritional support improves clinical outcome, it is considered a necessary strategy in the global treatment of sepsis. Recent developments in the knowledge of new substrates, such as olive oil–based emulsions or gamma-linolenic acid, open new perspectives as substrates that may modulate the inflammatory response in severe sepsis when adult respiratory syndrome or gastrointestinal failure may develop. However, the different effects that lipids have in immunomodulation, such as actions on cellular membranes, receptors, and intracellular signaling, make it difficult to point to fats as merely energy substrates. Regarding protein support, branched-chain amino acids, arginine, and glutamine seem to offer the most convenient alternative to standard formulations. Micronutrients play an important role, especially vitamins and some trace elements that perform an important function as antioxidant scavengers. Although vitamin needs have not been established for septic patients, the varied published recommendations seem to be far below the needs of these critically ill patients. Enteral nutrition remains to be preferable to intravenous, but the changes found in intestinal absorption and transport in severe sepsis may limit the use of enteral feeding. In some cases, it may not be possible or wise to provide adequate nutritional requirements via this route. …