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Clinical Pulmonary Medicine
Pulmonary embolism in pregnancy: A diagnostic conundrum
Pulmonary embolism (PE) is the 6th leading cause of maternal mortality in the United States. The clinical signs and symptoms of PE are usually nonspecific and often overlap with the normal physiologic changes of pregnancy. Due to low specificity and sensitivity of D-dimer test, pregnant patients with suspected PE often undergo CT pulmonary angiography (CTPA) and ventilation-perfusion scanning, both of which can cause radiation exposure to mother and fetus.
To answer whether pregnancy-adapted YEARS algorithm (Van der Hulle T et al. Lancet. 2017;390[10091]:289) can be safely used to avoid diagnostic imaging, Artemis Study Investigators prospectively studied three criteria from YEARS algorithm in combination with a D-dimer level (Van der Pol et al. N Engl J Med. 2019;380[12]:1139. The three criteria included clinical signs of deep-vein thrombosis (DVT), hemoptysis, and PE as the most likely diagnosis. PE was considered ruled out when none of the three criteria were present and D-dimer was less than 1000 ng/mL or if one or more of the criteria were met and D-dimer was less than 500 ng/mL. Patients in whom D-dimer was greater than 1000 ng/mL or in those with D-dimer greater than 500 ng/mL and had 1 or more of the YEARS algorithm criteria present, PE could not be ruled out and underwent CTPA. A modification of the criteria was done only for patients who had clinical signs of DVT at baseline. These patients underwent compression ultrasonography and if a clot was found, CTPA was not performed and patients were started on anticoagulation therapy. Those with negative DVT studies were subclassified based on D-dimer levels as the study population above. Patients in whom pulmonary embolism was not ruled out underwent CTPA. Of these 299 patients, 16 (5.4%) were confirmed to have PE at baseline.
In the remaining 195 patients in whom PE was ruled out on the basis of study protocol, a 3-month follow-up diagnosed one patient (0.51%) with VTE. Using pregnancy-adapted YEARS algorithm, CTPA was avoided in 39% of the patients of which 65% were in their first trimester when the radiation exposure can be most harmful to the fetus.
Muhammad Adrish, MD, FCCP
Steering Committee Member
Munish Luthra, MD, FCCP
Steering Committee Member
Cardiovascular Medicine and Surgery
Physical examination of low cardiac output in the ICU
Rapid evaluation of shock requires identifying signs of tissue hypoperfusion and differentiating between cardiogenic, obstructive, hypovolemic, and vasodilatory etiologies. Cardiac abnormalities may also contribute to mixed shock states in a broad array of critically ill patients. Left ventricular dysfunction in inpatients correlates with physical exam, with a 2.0 positive likelihood ratio and 0.41 negative likelihood ratio (Simel DL, Rennie D, eds. The Rational Clinical Examination: Evidence-Based Clinical Diagnosis. 2009). Accurate clinical assessment of cardiac output, however, is a fraught endeavor. In a recently published large series of patients with unplanned ICU admission, atrial fibrillation, systolic blood pressure (BP) < 90, altered consciousness, capillary refill time >4.5 seconds at the sternum, or skin mottling over the knee predicted low cardiac output with specificity >90%. Of 280 patients with a cardiac index of < 2.2 L/min/m2, less than half had any one of these findings (Hiemstra, et al. Intensive Care Med. 2019;45[2]:190).
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
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
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
Clinical Pulmonary Medicine
Pulmonary embolism in pregnancy: A diagnostic conundrum
Pulmonary embolism (PE) is the 6th leading cause of maternal mortality in the United States. The clinical signs and symptoms of PE are usually nonspecific and often overlap with the normal physiologic changes of pregnancy. Due to low specificity and sensitivity of D-dimer test, pregnant patients with suspected PE often undergo CT pulmonary angiography (CTPA) and ventilation-perfusion scanning, both of which can cause radiation exposure to mother and fetus.
To answer whether pregnancy-adapted YEARS algorithm (Van der Hulle T et al. Lancet. 2017;390[10091]:289) can be safely used to avoid diagnostic imaging, Artemis Study Investigators prospectively studied three criteria from YEARS algorithm in combination with a D-dimer level (Van der Pol et al. N Engl J Med. 2019;380[12]:1139. The three criteria included clinical signs of deep-vein thrombosis (DVT), hemoptysis, and PE as the most likely diagnosis. PE was considered ruled out when none of the three criteria were present and D-dimer was less than 1000 ng/mL or if one or more of the criteria were met and D-dimer was less than 500 ng/mL. Patients in whom D-dimer was greater than 1000 ng/mL or in those with D-dimer greater than 500 ng/mL and had 1 or more of the YEARS algorithm criteria present, PE could not be ruled out and underwent CTPA. A modification of the criteria was done only for patients who had clinical signs of DVT at baseline. These patients underwent compression ultrasonography and if a clot was found, CTPA was not performed and patients were started on anticoagulation therapy. Those with negative DVT studies were subclassified based on D-dimer levels as the study population above. Patients in whom pulmonary embolism was not ruled out underwent CTPA. Of these 299 patients, 16 (5.4%) were confirmed to have PE at baseline.
In the remaining 195 patients in whom PE was ruled out on the basis of study protocol, a 3-month follow-up diagnosed one patient (0.51%) with VTE. Using pregnancy-adapted YEARS algorithm, CTPA was avoided in 39% of the patients of which 65% were in their first trimester when the radiation exposure can be most harmful to the fetus.
Muhammad Adrish, MD, FCCP
Steering Committee Member
Munish Luthra, MD, FCCP
Steering Committee Member
Cardiovascular Medicine and Surgery
Physical examination of low cardiac output in the ICU
Rapid evaluation of shock requires identifying signs of tissue hypoperfusion and differentiating between cardiogenic, obstructive, hypovolemic, and vasodilatory etiologies. Cardiac abnormalities may also contribute to mixed shock states in a broad array of critically ill patients. Left ventricular dysfunction in inpatients correlates with physical exam, with a 2.0 positive likelihood ratio and 0.41 negative likelihood ratio (Simel DL, Rennie D, eds. The Rational Clinical Examination: Evidence-Based Clinical Diagnosis. 2009). Accurate clinical assessment of cardiac output, however, is a fraught endeavor. In a recently published large series of patients with unplanned ICU admission, atrial fibrillation, systolic blood pressure (BP) < 90, altered consciousness, capillary refill time >4.5 seconds at the sternum, or skin mottling over the knee predicted low cardiac output with specificity >90%. Of 280 patients with a cardiac index of < 2.2 L/min/m2, less than half had any one of these findings (Hiemstra, et al. Intensive Care Med. 2019;45[2]:190).
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
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
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
Clinical Pulmonary Medicine
Pulmonary embolism in pregnancy: A diagnostic conundrum
Pulmonary embolism (PE) is the 6th leading cause of maternal mortality in the United States. The clinical signs and symptoms of PE are usually nonspecific and often overlap with the normal physiologic changes of pregnancy. Due to low specificity and sensitivity of D-dimer test, pregnant patients with suspected PE often undergo CT pulmonary angiography (CTPA) and ventilation-perfusion scanning, both of which can cause radiation exposure to mother and fetus.
To answer whether pregnancy-adapted YEARS algorithm (Van der Hulle T et al. Lancet. 2017;390[10091]:289) can be safely used to avoid diagnostic imaging, Artemis Study Investigators prospectively studied three criteria from YEARS algorithm in combination with a D-dimer level (Van der Pol et al. N Engl J Med. 2019;380[12]:1139. The three criteria included clinical signs of deep-vein thrombosis (DVT), hemoptysis, and PE as the most likely diagnosis. PE was considered ruled out when none of the three criteria were present and D-dimer was less than 1000 ng/mL or if one or more of the criteria were met and D-dimer was less than 500 ng/mL. Patients in whom D-dimer was greater than 1000 ng/mL or in those with D-dimer greater than 500 ng/mL and had 1 or more of the YEARS algorithm criteria present, PE could not be ruled out and underwent CTPA. A modification of the criteria was done only for patients who had clinical signs of DVT at baseline. These patients underwent compression ultrasonography and if a clot was found, CTPA was not performed and patients were started on anticoagulation therapy. Those with negative DVT studies were subclassified based on D-dimer levels as the study population above. Patients in whom pulmonary embolism was not ruled out underwent CTPA. Of these 299 patients, 16 (5.4%) were confirmed to have PE at baseline.
In the remaining 195 patients in whom PE was ruled out on the basis of study protocol, a 3-month follow-up diagnosed one patient (0.51%) with VTE. Using pregnancy-adapted YEARS algorithm, CTPA was avoided in 39% of the patients of which 65% were in their first trimester when the radiation exposure can be most harmful to the fetus.
Muhammad Adrish, MD, FCCP
Steering Committee Member
Munish Luthra, MD, FCCP
Steering Committee Member
Cardiovascular Medicine and Surgery
Physical examination of low cardiac output in the ICU
Rapid evaluation of shock requires identifying signs of tissue hypoperfusion and differentiating between cardiogenic, obstructive, hypovolemic, and vasodilatory etiologies. Cardiac abnormalities may also contribute to mixed shock states in a broad array of critically ill patients. Left ventricular dysfunction in inpatients correlates with physical exam, with a 2.0 positive likelihood ratio and 0.41 negative likelihood ratio (Simel DL, Rennie D, eds. The Rational Clinical Examination: Evidence-Based Clinical Diagnosis. 2009). Accurate clinical assessment of cardiac output, however, is a fraught endeavor. In a recently published large series of patients with unplanned ICU admission, atrial fibrillation, systolic blood pressure (BP) < 90, altered consciousness, capillary refill time >4.5 seconds at the sternum, or skin mottling over the knee predicted low cardiac output with specificity >90%. Of 280 patients with a cardiac index of < 2.2 L/min/m2, less than half had any one of these findings (Hiemstra, et al. Intensive Care Med. 2019;45[2]:190).
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
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
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