NetWorks

Clinical pulmonary medicine. Cardiovascular medicine and surgery. Chest infections. Interprofessional team.


 

Regarding determination of shock etiology, in a small series of patients with systolic blood pressure < 90 mm Hg, physical exam findings of relatively warm skin temperature and rapid capillary refill had 89% sensitivity for vasodilatory shock, and jugular venous pressure ≥8 had 82% sensitivity for cardiogenic etiologies (Vazquez, et al. J Hosp Med. 2010;5[8]:471). Thus, while physical exam findings may inform bedside shock assessment, their accuracy is limited. Critical care physicians should consider additional assessment techniques, such as echocardiography or invasive hemodynamic monitoring, if diagnostic uncertainty persists (Vincent, et al. N Engl J Med. 2013;369[18]:1726).

Benjamin Kenigsberg, MD
Steering Committee Member

Dr. David Bowton and Dr. Steven Hollenberg contributed to the article.

Chest Infections

Lung infections in the transplant recipients

Dr. Raed Alalawi

The increase in lung transplantation over the years led to lung transplant recipients presenting to pulmonologists outside of specialized centers. One of the most common presentations is for infections. Infections account for more than 25% of all posttransplant deaths (Yusen, et al. J Heart Lung Transplant. 2014;33[10]:1009.

Multiple factors contribute to this increased infection risk, including donor lung colonization, disruption of local host defenses, constant contact with environmental pathogens, and heavy immunosuppression (Redmund KF, et al. Proc Am Thorac Soc. 2009;6[1]:94).

The onset of infectious manifestations, from the time of transplantation, is variable, depending on the organism. Based on the time of onset, infections can be categorized into within the first month posttransplant, 1 to 6 months, and beyond 6 months, posttransplant. During the first month, because of allograft colonization, preexisting infections in the recipient, and surgical- and hospital-acquired nosocomial infections are more common. The first 6 months are where the patients are at the highest risk for opportunistic infections. As the immunosuppression is lowered after 6 months, the causative organisms tend to be more common pathogens (Green M. Am J Transplant. 2013;13 [suppl 4]:3-8).

An early, aggressive, empiric antimicrobial therapy initiation and proactive, invasive diagnostic approach with needed testing to identify the potential pathogen, is imperative in these patients. Early bronchoscopy with bronchoalveolar lavage remains the most sensitive test to identify pathogens. Therapy can then be tailored toward the identified pathogen.

As part of the Chest Infections NetWork, we would like to raise awareness of lung infections in unique subgroups, such as lung transplant recipients. Treating infections in such patients requires a high index of suspicion in the setting of an atypical presentation.

Raed Alalawi, MD, FCCP
Steering Committee Member

Interprofessional Team

Extracorporeal Membrane Oxygenation (ECMO) in Near Fatal Asthma

Dr. Robert Baeten

Near fatal asthma (NFA) is defined as acute severe asthma characterized by acute respiratory failure with hypercapnia and/or respiratory acidosis requiring ventilator support. NFA refractory to conventional medical management and ventilator therapy can lead to fatal outcomes. Near fatal asthma also carries substantial mortality if invasive ventilation is needed (Marquette CH, et al. Am Rev Respir Dis. 1992;146[1]:76). Use of sedatives can exacerbate bronchospasm, and positive pressure ventilation can exacerbate dynamic hyperinflation, impairing hemodynamics, and gas exchange, and leading to barotrauma. This approach seems contrary to the goals of management. Outside of conventional therapies, such as IV steroids and inhaled beta-agonists, the data supporting other therapies such as IV beta-agonists, MgSO4, methylxanthines, mucolytics, heliox, and volatile anesthetics are scant. In contrast, venovenous ECMO can provide adequate gas exchange and prevent lung injury induced by mechanical ventilation and may be an effective bridging strategy to avoid aggressive ventilation in refractory NFA (Hye Ju Yeo, et al. Critical Care. 2017;21[1]:297).

Use of early ECMO to permit spontaneous breathing while the circuit accomplishes required ventilation and oxygenation seems more ideal. Avoidance of mechanical ventilation not only prevents complications like barotrauma but also may reduce delirium, malnutrition, and neuromuscular dysfunction. Performing “awake” ECMO has successfully been described for obstructive airway disease (Langer T, et al. Critical Care. 2016;20[1]:150). Factors limiting this approach are the invasive nature of ECMO and the inherent risks of large cannula dislodgement; however, the safety of this has been demonstrated with ambulation of ECMO patients to receive physical therapy (Abrams D, et al. Ann Cardiothorac Surg. 2019;8[1]:44). Alternatively, extracorporeal carbon dioxide removal (ECCO2R) systems utilize smaller catheters to satisfactorily remove CO2 while oxygen supplementation could be achieved via nasal cannula (Pisani L, et al. Respiratory Care. 2018;63[9]:1174). Incorporation of ECMO in select cases of NFA, especially ECCO2R, should be considered as an early rather than rescue therapy for acute severe asthma refractory to conventional medical therapy.

Robert Baeten, DMSc, PA-C, FCCP
Steering Committee Member

Munish Luthra MD, FCCP
Steering Committee Member

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