Christopher S. Davis

The acute pulmonary inflammatory response to the graded severity of smoke inhalation injury.

Objectives:To determine whether the graded severity of smoke inhalation is reflected by the acute pulmonary inflammatory response to injury. Design:In a prospective observational study, we assessed the bronchoalveolar lavage fluid for both leukocyte differential and concentration of 28 cytokines, chemokines, and growth factors. Results were then compared to the graded severity of inhalation injury as determined by Abbreviated Injury Score criteria (0, none; 1, mild; 2, moderate; 3, severe; 4, massive). Setting:All patients were enrolled at a single tertiary burn center. Patients:The bronchoalveolar lavage fluid was obtained from 60 patients within 14 hrs of burn injury who underwent bronchoscopy for suspected smoke inhalation. Interventions:None. Measurements and Main Results:Those who presented with worse grades of inhalation injury had higher plasma levels of carboxyhemoglobin and enhanced airway neutrophilia. Patients with the most severe inhalation injuries also had a greater requirement for tracheostomy, longer time on the ventilator, and a prolonged stay in the intensive care unit. Of the 28 inflammatory mediators assessed in the bronchoalveolar lavage fluid, 21 were at their highest in those with the worst inhalation injury scores (grades 3 and 4), the greatest of which was interleukin-8 (92,940 pg/mL, grade 4). When compared in terms of low inhalation injury (grades 1–2) vs. high inhalation injury (grades 3–4), we found significant differences between groups for interleukin-4, interleukin-6, interleukin-9, interleukin-15, interferon-&ggr;, granulocyte-macrophage colony-stimulating factor, and monocyte chemotactic protein-1 (p < .05 for all). Conclusions:These data reveal that the degree of inhalation injury has basic and profound effects on burn patient morbidity, evokes complex changes of multiple alveolar inflammatory proteins, and is a determinant of the pulmonary inflammatory response to smoke inhalation. Accordingly, future investigations should consider inhalation injury to be a graded phenomenon. (Crit Care Med 2012; 40:–1121)

The protective role of laparoscopic antireflux surgery against aspiration of pepsin after lung transplantation.

BACKGROUND The goal of this study was to determine, in lung transplant patients, if laparoscopic antireflux surgery (LARS) is an effective means to prevent aspiration as defined by the presence of pepsin in the bronchoalveolar lavage fluid (BALF). METHODS Between September 2009 and November 2010, we collected BALF from 64 lung transplant patients at multiple routine surveillance assessments for acute cellular rejection, or when clinically indicated for diagnostic purposes. The BALF was tested for pepsin by enzyme-linked immunosorbent assay (ELISA). We then compared pepsin concentrations in the BALF of healthy controls (n = 11) and lung transplant patients with and without gastroesophageal reflux disease (GERD) on pH-monitoring (n = 8 and n = 12, respectively), and after treatment of GERD by LARS (n = 19). Time to the development of bronchiolitis obliterans syndrome was contrasted between groups based on GERD status or the presence of pepsin in the BALF. RESULTS We found that lung transplant patients with GERD had more pepsin in their BALF than lung transplant patients who underwent LARS (P = .029), and that pepsin was undetectable in the BALF of controls. Moreover, those with more pepsin had quicker progression to BOS and more acute rejection episodes. CONCLUSION This study compared pepsin in the BALF from lung transplant patients with and without LARS. Our data show that: (1) the detection of pepsin in the BALF proves aspiration because it is not present in healthy volunteers, and (2) LARS appears effective as a measure to prevent the aspiration of gastroesophageal refluxate in the lung transplant population. We believe that these findings provide a mechanism for those studies suggesting that LARS may prevent nonallogenic injury to the transplanted lungs from aspiration of gastroesophageal contents.

The evolution and long-term results of laparoscopic antireflux surgery for the treatment of gastroesophageal reflux disease.

When carefully performed, laparoscopic antireflux surgery is an effective, durable procedure for the control of gastroesophageal reflux disease.

Medium and long-term outcomes after pneumatic dilation or laparoscopic Heller myotomy for achalasia: a meta-analysis.

Recent randomized studies comparing outcomes after pneumatic dilation (PD) and laparoscopic Heller myotomy (LHM) for the treatment of achalasia are conflicting and limited to short-term follow-up. Our meta-analysis compared the long-term durability of these approaches, with the hypothesis that LHM offers superior long-term remission compared with PD. We identified 36 studies published between 2001 and 2011 with at least 5 years of follow-up. Those studies describing PD included 3211 patients (mean age, 49.8 y). For PD, the mean 5-year remission rate was 61.9% and the mean 10-year remission rate was 47.9%. Overall, 1526 patients (mean age, 46.3 y) were treated with LHM; 83% received a fundoplication. In contrast, the mean 5- and 10-year remission rates after LHM were 76.1% and 79.6%, respectively. Finally, the perforation rate for LHM was twice that of PD (4.8% vs. 2.4%; P<0.05). We conclude that despite a higher frequency of perforation, LHM affords greater long-term durability.

Gastroesophageal reflux disease after lung transplantation: pathophysiology and implications for treatment.

BACKGROUND Gastroesophageal reflux disease (GERD) is thought to be a risk factor for the development or progression of chronic rejection after lung transplantation. However, the prevalence of GERD and its risk factors, including esophageal dysmotility, hiatal hernia and delayed gastric emptying after lung transplantation, are still unknown. In addition, the prevalence of Barretts esophagus, a known complication of GERD, has not been determined in these patients. The purpose of this study was to determine the prevalence and extent of GERD, as well as the frequency of these risk factors and complications of GERD in lung transplant patients. METHODS Thirty-five consecutive patients underwent a combination of esophageal function testing, upper endoscopy, barium swallow, and gastric emptying scan after lung transplantation. RESULTS In this patient population, the prevalence of GERD was 51% and 22% in those who had been retransplanted. Of patients with GERD,36% had ineffective esophageal motility (IEM), compared with 6% of patients without GERD (P = .037). No patient demonstrated hiatal hernia on barium swallow. The prevalence of delayed gastric emptying was 36%. The prevalence of biopsy-confirmed Barretts esophagus was 12%. CONCLUSION Our study shows that, after lung transplantation, more than half of patients had GERD, and that GERD was more common after retransplantation. IEM and delayed gastric emptying are frequent in patients with GERD. Hiatal hernia is rare. The prevalence of Barretts esophagus is not negligible. We conclude that GERD is highly prevalent after lung transplantation, and that delayed gastric emptying and Barretts esophagus should always be suspected after lung transplantation because they are common risks factors and complications of GERD.

Early Pulmonary Immune Hyporesponsiveness Is Associated With Mortality After Burn and Smoke Inhalation Injury

This prospective study aims to address mortality in the context of the early pulmonary immune response to burn and inhalation injury. The authors collected bronchoalveolar lavage fluid from 60 burn patients within 14 hours of their injury when smoke inhalation was suspected. Clinical and laboratory parameters and immune mediator profiles were compared with patient outcomes. Patients who succumbed to their injuries were older (P = .005), had a larger % TBSA burn (P < .001), and required greater 24-hour resuscitative fluids (P = .002). Nonsurvivors had lower bronchoalveolar lavage fluid concentrations of numerous immunomodulators, including C5a, interleukin (IL)-1&bgr;, IL-1RA, IL-8, IL-10, and IL-13 (P < .05 for all). Comparing only those with the highest Baux scores to account for the effects of age and % TBSA burn on mortality, nonsurvivors also had reduced levels of IL-2, IL-4, granulocyte colony-stimulating factor, interferon-&ggr;, macrophage inflammatory protein-1&bgr;, and tumor necrosis factor-&agr; (P < .05 for all). The apparent pulmonary immune hyporesponsiveness in those who died was confirmed by in vitro culture, which revealed that pulmonary leukocytes from nonsurvivors had a blunted production of numerous immune mediators. This study demonstrates that the early pulmonary immune response to burn and smoke inhalation may be attenuated in patients who succumb to their injuries.

Inhalation injury severity and systemic immune perturbations in burned adults.

Objective:We aimed to determine whether the severity of inhalation injury evokes an immune response measurable at the systemic level and to further characterize the balance of systemic pro- and anti-inflammation early after burn and inhalation injury. Background:Previously, we reported that the pulmonary inflammatory response is enhanced with worse grades of inhalation injury and that those who die of injuries have a blunted pulmonary immune profile compared with survivors. Methods:From August 2007 to June 2011, bronchoscopy was performed on 80 patients admitted to the burn intensive care unit when smoke inhalation was suspected. Of these, inhalation injury was graded into 1 of 5 categories (0, 1, 2, 3, and 4), with grade 0 being the absence of visible injury and grade 4 corresponding to massive injury. Plasma was collected at the time of bronchoscopy and analyzed for 28 immunomodulating proteins via multiplex bead array or enzyme-linked immunosorbent assay. Results:The concentrations of several plasma immune mediators were increased with worse inhalation injury severity, even after adjusting for age and % total body surface area (TBSA) burn. These included interleukin (IL)-1RA (P = 0.002), IL-6 (P = 0.002), IL-8 (P = 0.026), granulocyte colony-stimulating factor (P = 0.002), and monocyte chemotactic protein 1 (P = 0.007). Differences in plasma immune mediator concentrations in surviving and deceased patients were also identified. Briefly, plasma concentrations of IL-1RA, IL-6, IL-8, IL-15, eotaxin, and monocyte chemotactic protein 1 were higher in deceased patients than in survivors (P < 0.05 for all), whereas IL-4 and IL-7 were lower (P < 0.05). After adjusting for the effects of age, % TBSA burn, and inhalation injury grade, plasma IL-1RA remained significantly associated with mortality (odds ratio, 3.12; 95% confidence interval, 1.03–9.44). Plasma IL-1RA also correlated with % TBSA burn, inhalation injury grade, fluid resuscitation, Baux score, revised Baux score, Denver score, and the Sequential Organ Failure Assessment score. Conclusions:The severity of smoke inhalation injury has systemically reaching effects, which argue in favor of treating inhalation injury in a graded manner. In addition, several plasma immune mediators measured early after injury were associated with mortality. Of these, IL-1RA seemed to have the strongest correlation with injury severity and outcomes measures, which may explain the blunted pulmonary immune response we previously found in nonsurvivors.

Laparoscopic Antireflux Surgery for Gastroesophageal Reflux Disease After Lung Transplantation

BACKGROUND Although gastroesophageal reflux disease (GERD) is highly prevalent in lung transplantation, the pathophysiology of GERD in these patients is unknown. We hypothesize that the pathophysiology of GERD after lung transplantation differs from that of a control population, and that the 30-d morbidity and mortality of laparoscopic antireflux surgery (LARS) are equivalent in both populations. METHODS We retrospectively compared the pathophysiology of GERD and the 30-d morbidity and mortality of 29 consecutive lung transplant patients with 23 consecutive patients without lung transplantation (control group), all of whom had LARS for GERD between November 2008 and May 2010. RESULTS Both groups had a similar prevalence of endoscopic esophagitis and Barretts esophagus , comparable manometric profiles, and similar prevalence of abnormal peristalsis. However, hiatal hernia was more common in controls than in lung transplant patients (57% versus 24%; P = 0.04). Lung transplant patients had a higher prevalence and severity of proximal GERD (65% versus 33%; P = 0.04). The 30-d morbidity and mortality following LARS were similar in both groups regardless of the higher surgical risk of lung transplants (median ASA class: 3 versus 2 for controls, P < 0.001). CONCLUSIONS These results show that despite similar manometric profiles, lung transplant patients are more prone to proximal reflux than the general population with GERD; the prevalence of endoscopic esophagitis and Barretts esophagus is the same in both groups of patients; a hiatal hernia is uncommon after lung transplantation; and the morbidity and mortality of LARS are the same for lung transplant patients as the general population with GERD.

Gastroesophageal reflux disease in lung transplant patients with cystic fibrosis

BACKGROUND Gastroesophageal reflux disease (GERD) in lung transplant patients is being increasingly investigated because of its reported association with chronic rejection. However, information concerning the characteristics of GERD in cystic fibrosis (CF) patients is scarce. METHODS We compared esophageal pH monitoring, manometry, gastric emptying studies, and barium swallow of 10 lung transplant patients with CF with those of 78 lung transplant patients with other end-stage pulmonary diseases. RESULTS In lung transplant patients with CF, the prevalence of GERD was 90% (vs 54% controls, P = .04), of whom 70% had proximal reflux (vs 29% controls, P = .02). CONCLUSIONS Lung transplant patients with CF have a significantly higher prevalence and proximal extent of GERD than do other lung transplant recipients. These data suggest that CF patients in particular should be routinely screened for GERD after transplantation to identify those who may benefit from antireflux surgery, especially given the risks of GERD-related aspiration and chronic allograft injury.

Pepsin concentrations are elevated in the bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis after lung transplantation

BACKGROUND Aspiration of gastroesophageal refluxate has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF) and the progression of bronchiolitis obliterans syndrome after lung transplantation. The goals of the present study were to identify lung transplant patients at the greatest risk of aspiration and to investigate the causative factors. MATERIALS AND METHODS From September 2009 to November 2011, 252 bronchoalveolar lavage fluid (BALF) samples were collected from 100 lung transplant patients. The BALF pepsin concentrations and the results of transbronchial biopsy, esophageal function testing, barium swallow, and gastric emptying scan were compared among those with the most common end-stage lung diseases requiring lung transplantation: IPF, chronic obstructive pulmonary disease, cystic fibrosis, and α1-antitrypsin deficiency. RESULTS Patients with IPF had higher BALF pepsin concentrations and a greater frequency of acute rejection than those with α1-antitrypsin deficiency, cystic fibrosis, or chronic obstructive pulmonary disease (P = 0.037). Moreover, the BALF pepsin concentrations correlated negatively with a lower esophageal sphincter pressure and distal esophageal amplitude; negatively with distal esophageal amplitude and positively with total esophageal acid time, longest reflux episode, and DeMeester score in those with chronic obstructive pulmonary disease; and negatively with the upright acid clearance time in those with IPF. CONCLUSIONS Our results suggest that patients with IPF after lung transplantation are at increased risk of aspiration and a greater frequency of acute rejection episodes, and that the risk factors for aspiration might be different among those with the most common end-stage lung diseases who have undergone lung transplantation. These results support the role of evaluating the BALF for markers of aspiration in assessing lung transplant patients as candidates for antireflux surgery.