Ajit Moghekar

Right Ventricular Echocardiographic Parameters Are Associated with Mortality after Acute Pulmonary Embolism

BACKGROUND There is limited information on the utility of certain echocardiographic measurements, such as right ventricular (RV) strain analysis, in predicting mortality in patients with acute pulmonary embolism (PE). METHODS A total of 211 patients with acute PE admitted to a medical intensive care unit (ICU) were retrospectively identified. Echocardiographic variables were prospectively measured in this cohort. The focus was on ICU, hospital, and long-term mortality. RESULTS The mean age was 61 ± 15 years. Median Acute Physiology and Chronic Health Evaluation IV and simplified Pulmonary Embolism Severity Index scores were 60 (interquartile range, 40-71) and 2 (interquartile range, 1-2), respectively. Thirty-eight patients (18%) died during the sentinel hospitalization (13% died in the ICU). A total of 61 patients (28.9%) died during a median follow-up period of 15 months (interquartile range, 5-26 months). The echocardiographic variables associated with long-term mortality (from PE diagnosis) were ratio of RV to left ventricular end-diastolic diameter (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.2-4.8), tricuspid annular plane systolic excursion (HR, 0.53; 95% CI, 0.31-0.92), and RV-right atrial gradient (HR, 1.02; 95% CI, 1.01-1.4). ICU mortality was associated with ratio of RV to LV end-diastolic diameter (HR, 4.4; 95% CI, 1.3-15), RV systolic pressure (HR, 1.03; 95% CI, 1.01-1.05), tricuspid annular plane systolic excursion (HR, 0.4; 95% CI, 0.18-0.9), and inferior vena cava collapsibility < 50% (HR, 4.3; 95% CI, 1.7-11). These variables remain significantly associated with mortality after adjusting by Acute Physiology and Chronic Health Evaluation IV score, Pulmonary Embolism Severity Index score, or the use of thrombolytic agents. RV strain parameters were not correlated with hospital or long-term mortality. CONCLUSIONS Four simple parameters that measure different aspects of the right ventricle (ratio of RV to left ventricular end-diastolic diameter, RV systolic pressure, tricuspid annular plane systolic excursion, and inferior vena cava collapsibility) were independently associated with mortality in patients presenting with acute PE who were admitted to the ICU.

Revisiting Ultrasound-Guided Subclavian/Axillary Vein Cannulations: Importance of Pleural Avoidance With Rib Trajectory:

The Centers for Disease Control and Prevention guidelines for the prevention of catheter-related bloodstream infections suggest using “a subclavian site, rather than an internal jugular or a femoral site, in adult patients.” This recommendation is based on evidence of lower rates of thrombosis and catheter-related bloodstream infections in patients with subclavian central venous catheters (CVCs) compared to femoral or internal jugular sites. However, preference toward a subclavian approach to CVC insertion is hindered by increased risk of mechanical complications, especially pneumothorax, when compared to other sites. This is largely related to the proximity of the subclavian vein to the pleural space and the traditional “blind” or anatomic landmark approach used in subclavian vein cannulation. We revisit a method that may provide increased safety and avoidance of pneumothorax during ultrasound-guided subclavian/axillary vein cannulation. This is achieved by directing the needle toward the subclavian vein at a point where it traverses over the second rib, providing a protective rib shield between the vessel and pleura as a safety net for operators. The technique also allows for increased compressibility of the subclavian/axillary vein in the event of bleeding complication.

Utilization of Thoracic Ultrasound for Confirmation of Central Venous Catheter Placement and Exclusion of Pneumothorax: A Novel Technique in Real-Time Application

Aim: To evaluate the safety and utility of ultrasonography as a tool to confirm central venous catheter (CVC) position and to exclude insertion-related pneumothorax in place of chest radiography (CXR) in a tertiary medical intensive care unit (ICU). Methods: We randomized 60 consecutive medical ICU patients to conventional or ultrasound groups for CVC placement. Both groups had CVCs inserted under ultrasound guidance. The intervention group underwent real-time transthoracic echocardiography to assist in catheter positioning and chest ultrasonography for exclusion of pneumothorax. Our primary end point was reduction in CXR use. The secondary end point was time elapsed from the end of procedure to the availability of CVC for use. χ2 test was used to compare the 2 groups for the primary end point. T test was used to compare the 2 groups for the secondary end point. Results: Thirty patients were randomized to the conventional group and 30 were randomized to the ultrasound group. One patient was excluded in the control group since the procedure needed to be aborted. Patient characteristics were well matched for age, body mass index, and acute physiologic assessment and chronic health evaluation (APACHE III) scores. There was a 56.7% (P < .0001) reduction in CXR use in the ultrasound arm. Mean time to use was 53.6 minutes in the control group and 25 minutes in the ultrasound arm (P = .0015). Mean time required to complete the procedure was 27.7 minutes in the control group and 24.1 minutes in the ultrasound group (P = .2053). No pneumothorax was detected in either arm. Conclusion: Ultrasound-guided CVC placement and positioning with a minor modification in technique reduced the use of bedside CXR and reduced the time to use of the CVC.

Thoracic ultrasound: Picture worth a thousand sounds

poses a risk of transportation of a critically ill patient, and its inappropriate use increases healthcare costs. Despite these limitations, radiographs and CT scans are invaluable for evaluating lung pathology. However, there remains a need for an imaging technology that not only provide useful and accurate information but is also cost effective and free of risk to the patient. With significant improvements in image quality and ease of use, ultrasound has the ability to address some of the limitations of chest radiographs and CT scans. Thoracic ultrasound provides a dynamic evaluation of the pleural space and the lung, without radiation and therefore is considered safe. This is especially useful for repeat evaluations after therapeutic interventions. Additionally, compact and easily portable machines have now enabled physicians to themselves perform the exam and interpret the images in real time to make instant clinical decisions at the bedside. Thus the ‘point of care’ ultrasonography is now a powerful tool for the intensivist and the pulmonologist, which has the potential to improve clinical decisions and consequent patient outcomes. While the use of ultrasound to evaluate pleural effusion and guide thoracentesis was first described in 1967,

A Patient With Lung Cancer Presenting With Respiratory Failure and Shock

A 62-year-old woman with a recent diagnosis of nonsmall cell lung cancer was admitted to the oncology service from her outpatient clinic for progressive dyspnea on exertion. Three weeks prior to admission she was found to have metastatic adenocarcinoma with endobronchial invasion of the trachea and right mainstem bronchus requiring placement of a silicone Y stent (Dumon Y stents have been manufactured by Novatech since 1994) to maintain airway patency. Laboratory evaluation on admission revealed leukocytosis (WBC count, 23,000 cells/uL; 77% neutrophils), anemia (hemoglobin level, 8.5 g/dL, down from 9.5 g/dL on her last hospital discharge), and acute kidney injury (serum creatinine level, 2.7 mg/dL). Further workup of her dyspnea revealed a right lower lung fi eld opacity on chest radiograph, which was believed to be an alveolar consolidation or lung collapse ( Fig 1A ) and a ventilation/perfusion scan with a low probability of pulmonary embolism. Treatment with ceftriaxone and azithromycin was initiated for presumed community-acquired pneumonia. The following morning she was hypotensive and tachycardic, requiring transfer to the medical ICU (MICU) for further management of presumed severe sepsis. On admission to the MICU she had worsening leukocytosis (WBC count, 26,000 cells / m L) and anemia (hemoglobin level, 7.8 g/dL). IV fl uids and broadspectrum antibiotics were initiated. Chest radiograph was performed, and results are shown in Figure 1B . Hours after transfer to the MICU she developed worsening hypoxic respiratory failure and required endotracheal intubation. Bedside bronchoscopy was emergently performed to ensure that there was no stent migration or obstruction and revealed tumor invasion in the trachea above the Y stent without occlusion of the airway or active hemorrhage. Based on the radiographs, we performed a chest ultrasound to evaluate for an infi ltrate and/or an effusion amenable to drainage (Video 1). A Patient With Lung Cancer Presenting With Respiratory Failure and Shock

Radiation Exposure in the Medical ICU: Predictors and Characteristics

Background Patients admitted to the medical ICU (MICU) are often subjected to multiple radiologic studies. We hypothesized that some endure radiation dose exposure (cumulative effective dose [CED]) in excess of annual US federal occupational health standard limits (CED ≥ 50 mSv) and 5‐year cumulative limit (CED ≥ 100 mSv). We also evaluated the correlation of CED with Acute Physiology and Chronic Health Evaluation (APACHE) III score and other clinical variables. Methods Retrospective observational study conducted in an academic medical center involving all adult admissions (N = 4,155) to the MICU between January 2013 and December 2013. Radiation doses from ionizing radiologic studies were calculated from reference values to determine the CED. Results Three percent of admissions (n = 131) accrued CED ≥ 50 mSv (1% [n = 47] accrued CED ≥ 100 mSv). The median CED was 0.72 mSv (interquartile range, 0.02‐5.23 mSv), with a range of 0.00 to 323 mSv. Higher APACHE III scores (P = .003), longer length of MICU stay (P < .0001), sepsis (P = .03), and gastrointestinal disorders and bleeding (P < .0001) predicted higher CED in a multivariable linear regression model. Patients with gastrointestinal bleeding and disorders had an odds ratio of 21.05 (95% CI, 13.54‐32.72; P < .0001) and 6.94 (95% CI, 3.88‐12.38; P < .0001), respectively, of accruing CED ≥ 50 mSv in a multivariable logistic regression model. CT scan and interventional radiology accounted for 49% and 38% of the total CED, respectively. Conclusions Patients in the MICU are exposed to radiation doses that can be substantial, exceeding federal annual occupational limits, and in a select subset, are > 100 mSv. Efforts to justify, restrict, and optimize the use of radiologic resources when feasible are warranted.