Charles W. Hoopes

Safety of Nurse-Led Ambulation for Patients on Venovenous Extracorporeal Membrane Oxygenation

Purpose: Venovenous extracorporeal membrane oxygenation (VV ECMO) is an effective therapy in patients with acute lung injury and end-stage lung disease. Although immobility increases the risk of complications, ambulation of patients on VV ECMO is not the standard of care in many institutions. Staff concerns for patient safety remain a barrier to ambulation. In this case series, we present our experience utilizing a nurse-driven ambulatory VV ECMO process to safely rehabilitate patients. Methods: We retrospectively reviewed all VV ECMO cases at our institution between January 1, 2011, and November 1, 2013. Inclusion criteria for this study required patients to be cannulated in the right internal jugular vein and ambulated while on VV ECMO. Results: During the period from January 1, 2011, to November 1, 2013, 18 patients (mean age 49 ± 15 years, 12 male) were ambulated while on ECMO. Eight received a transplant and survived to discharge. Of the remaining patients, 4 were successfully weaned from VV ECMO and 6 died following decisions by the family to withdraw care. The mean duration of VV ECMO support was 18 ± 16 days with the maximum duration being 61 days. All patients received physical therapy, range of motion at the bedside, and ambulated in the hospital. There were no patient falls, decannulations, or any other complications related to ambulation. Conclusion: The adoption of a nurse-driven program to ambulate patients on VV ECMO is safe and may reduce other complications associated with immobility.

Distal airway microbiome is associated with immunoregulatory myeloid cell responses in lung transplant recipients

BACKGROUNDnLong-term survival of lung transplant recipients (LTRs) is limited by the occurrence of bronchiolitis obliterans syndrome (BOS). Recent evidence suggests a role for microbiome alterations in the occurrence of BOS, although the precise mechanisms are unclear. In this study we evaluated the relationship between the airway microbiome and distinct subsets of immunoregulatory myeloid-derived suppressor cells (MDSCs) in LTRs.nnnMETHODSnBronchoalveolar lavage (BAL) and simultaneous oral wash and nasal swab samples were collected from adult LTRs. Microbial genomic DNA was isolated, 16S rRNA genes amplified using V4 primers, and polymerase chain reaction (PCR) products sequenced and analyzed. BAL MDSC subsets were enumerated using flow cytometry.nnnRESULTSnThe oral microbiome signature differs from that of the nasal, proximal and distal airway microbiomes, whereas the nasal microbiome is closer to the airway microbiome. Proximal and distal airway microbiome signatures of individual subjects are distinct. We identified phenotypic subsets of MDSCs in BAL, with a higher proportion of immunosuppressive MDSCs in the proximal airways, in contrast to a preponderance of pro-inflammatory MDSCs in distal airways. Relative abundance of distinct bacterial phyla in proximal and distal airways correlated with particular airway MDSCs. Expression of CCAAT/enhancer binding protein (C/EBP)-homologous protein (CHOP), an endoplasmic (ER) stress sensor, was increased in immunosuppressive MDSCs when compared with pro-inflammatory MDSCs.nnnCONCLUSIONSnThe nasal microbiome closely resembles the microbiome of the proximal and distal airways in LTRs. The association of distinct microbial communities with airway MDSCs suggests a functional relationship between the local microbiome and MDSC phenotype, which may contribute to the pathogenesis of BOS.

Flexible Bronchoscopy Is Safe and Effective in Adult Subjects Supported With Extracorporeal Membrane Oxygenation

BACKGROUND: Previous studies have demonstrated the safety of flexible bronchoscopy (FB) in mechanically ventilated subjects. However, the safety of FB in adult subjects receiving extracorporeal membrane oxygenation (ECMO) has not been described previously. METHODS: A retrospective review was conducted of all adult subjects who underwent FB while receiving ECMO support at the University of Alabama at Birmingham Hospital from January 1, 2013, to December 31, 2014. Physiologic variables, pre- and post-FB ECMO, and ventilator settings were recorded. RESULTS: 79 adult subjects underwent FB receiving ECMO with a total of 223 bronchoscopies. The most common indications for bronchoscopy included diagnostic evaluation of infection in subjects with pneumonia (29%) and clearance of excessive secretions (22%). In 70% of subjects, moderate or greater amounts of secretions were noted. FB yielded positive culture data in 37 subjects (47%), which resulted in a change to the antibiotic regimen in 14 subjects (38%) with positive culture data. No significant differences in mean PaO2/FIO2, mean ECMO flow, mean sweep gas, ventilator settings, or hemodynamic parameters (heart rate, oxygen saturation, and mean blood pressure) were noted before and after FB. Complications were mild and transient: blood-tinged secretions after FB in 21% cases, which resolved spontaneously, intraprocedural hypoxemia in 2.2% of cases, and dysrhythmia in <1% of cases. There were no episodes of ECMO cannula dislodgement or inadvertent extubation. CONCLUSIONS: FB can be used safely in adult subjects supported with ECMO and is not associated with significant hemodynamics changes, bleeding, or mechanical complications during ECMO support.

Diaphragm Abnormalities in Patients with End-Stage Heart Failure: NADPH Oxidase Upregulation and Protein Oxidation

Patients with heart failure (HF) have diaphragm abnormalities that contribute to disease morbidity and mortality. Studies in animals suggest that reactive oxygen species (ROS) cause diaphragm abnormalities in HF. However, the effects of HF on ROS sources, antioxidant enzymes, and protein oxidation in the diaphragm of humans is unknown. NAD(P)H oxidase, especially the Nox2 isoform, is an important source of ROS in the diaphragm. Our main hypothesis was that diaphragm from patients with HF have heightened Nox2 expression and p47phox phosphorylation (marker of enzyme activation) that is associated with elevated protein oxidation. We collected diaphragm biopsies from patients with HF and brain-dead organ donors (controls). Diaphragm mRNA levels of Nox2 subunits were increased 2.5–4.6-fold over controls (p < 0.05). Patients also had increased protein levels of Nox2 subunits (p47phox, p22phox, and p67phox) and total p47phox phosphorylation, while phospho-to-total p47phox levels were unchanged. The antioxidant enzyme catalase was increased in patients, whereas glutathione peroxidase and superoxide dismutases were unchanged. Among markers of protein oxidation, carbonyls were increased by ~40% (p < 0.05) and 4-hydroxynonenal and 3-nitrotyrosines were unchanged in patients with HF. Overall, our findings suggest that Nox2 is an important source of ROS in the diaphragm of patients with HF and increases in levels of antioxidant enzymes are not sufficient to maintain normal redox homeostasis. The net outcome is elevated diaphragm protein oxidation that has been shown to cause weakness in animals.

Use of a novel pulmonary artery cannula to provide extracorporeal membrane oxygenation as a bridge to lung transplantation

We describe our surgical technique, the choice of the device, and discuss the procedure considerations unique to the apex anatomy. The Jarvik 2000 LVAD sewing cuff presents particular characteristics: it has an outer diameter of 42 mm and a silicon flange of 9.5 mm. Owing to these dimensions, it guarantees an efficient overlay of the larger ventriculotomy consequent to the previous Dor procedure or the removal of the calcification. In addition, it provides secure fixing of the cuff to the myocardium due to the larger and pliable surface of the silicon flange that allows the positioning of a higher number of mattress sutures and also makes possible the wrapping of the aneurism tissue with an overcasting suture (Figure 1C). Consequently, it provides better hemostasis and fixing of the inflow cannula, which is of great significance considering the fragile myocardium that is characteristic of these patients.

Delayed sternal closure does not reduce complications associated with coagulopathy and right ventricular failure after left ventricular assist device implantation

Delayed sternal closure (DSC) is occasionally adopted after implantation of left ventricular assist device (LVAD). Recent studies suggest that DSC be used for high risk group of patients with coagulopathy, hemodynamic instability or right ventricular failure. However, whether DSC is efficacious for bleeding complication or right ventricular failure is not known. This study is single center analysis of 52 patients, who underwent LVAD implantation. Of those 52 patients, 40 consecutive patients underwent DSC routinely. The sternum was left open with vacuum assist device after implantation of LVAD. Perioperative outcome of the patients who underwent routine DSC were compared with 12 patients who had immediate sternal closure (IC). Mean Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) level of IC group and DSC group were 2.7 and 2.6, respectively. Postoperative bleeding (643 vs. 1469xa0ml, pu2009<u20090.001), duration of inotropic support (109 vs. 172xa0h, pu2009=u20090.034), and time to extubation (26 vs. 52xa0h, pu2009=u20090.005) were significantly increased in DSC group. Length of ICU stay (14 vs. 15xa0days, pu2009=u20090.234) and hospital stay (28 vs. 20xa0days, pu2009=u20090.145) were similar. Incidence of right ventricular failure and tamponade were similar in the two groups. Routine DSC after implantation of an LVAD did not prove to be beneficial in reducing complications associated with coagulopathy and hemodynamic instability including cardiac tamponade or right ventricular failure. We suggest that DSC be selectively applied for patients undergoing LVAD implant.