Hemang Yadav

The right ventricular annular velocity reduction caused by coronary artery bypass graft surgery occurs at the moment of pericardial incision

Background Right ventricular (RV) long-axis function is known to be depressed after cardiac surgery, but the mechanism is not known. We hypothesized that intraoperative transesophageal echocardiography could pinpoint the time at which this happens to help narrow the range of plausible mechanisms. Method Transthoracic echocardiography was conducted in 33 patients before and after elective coronary artery bypass graft. In an intensively monitored cohort of 9 patients, we also monitored RV function intraoperatively using serial pulsed wave tissue Doppler (PW TD) transesophageal echocardiography. Results There was no significant difference in myocardial velocities from the onset of the operation up to the beginning of pericardial incision, change in RV PW TD S′ velocities 3% ± 2% (P = not significant). Within the first 3 minutes of opening the pericardium, RV PW TD S′ velocities had reduced by 43% ± 17% (P < .001). At 5 minutes postpericardial incision, 2 minutes later, the velocities had more than halved, by 54% ± 11% (P < .0001). Velocities thereafter remained depressed throughout the operation, with final intraoperative S′ reduction being 61% ± 11% (P < .0001). One month after surgery, in the full 33-patient cohort, transthoracic echocardiogram data showed a 55% ± 12% (P < .0001) reduction in RV S′ velocities compared with preoperative values. Conclusions Minute-by-minute monitoring during cardiac surgery reveals that, virtually, all the losses in RV systolic velocity occurs within the first 3 minutes after pericardial incision. Right ventricular long-axis reduction during coronary bypass surgery results not from cardiopulmonary bypass but rather from pericardial incision.

Characterizing the Epidemiology of Perioperative Transfusion-associated Circulatory Overload

Background:Transfusion-associated circulatory overload (TACO) is a leading cause of transfusion-related fatalities, but its incidence and associated patient and transfusion characteristics are poorly understood. To inform surgical transfusion practice and to begin mitigating perioperative TACO, the authors aimed to define its epidemiology. Methods:In this retrospective cohort study, the medical records of adult patients undergoing noncardiac surgery with general anesthesia during 2004 or 2011 and receiving intraoperative transfusions were screened using an electronic algorithm for identification of TACO. Those patients who were screened as high probability for TACO underwent rigorous manual review. Univariate and multivariate analyses evaluated associations between patient and transfusion characteristics with TACO rates in a before-and-after study design. Results:A total of 2,162 and 1,908 patients met study criteria for 2004 and 2011, respectively. The incidence of TACO was 5.5% (119 of 2,162) in 2004 versus 3.0% (57 of 1,908) in 2011 (P < 0.001), with comparable rates for men (4.8% [98 of 2,023]) and women (3.8% [78 of 2,047]) (P = 0.09). Overall, vascular (12.1% [60 of 497]), transplant (8.8% [17 of 193]), and thoracic surgeries (7.2% [10 of 138]) carried the highest TACO rates. Obstetric and gynecologic patients had the lowest rate (1.4% [4 of 295]). The incidence of TACO increased with volume transfused, advancing age, and total intraoperative fluid balance (all P < 0.001). Conclusions:The incidence of perioperative TACO is similar to previous estimates in nonsurgical populations. There was a reduction in TACO rate between 2004 and 2011, with incidence patterns remaining comparable in subgroup analyses. Future efforts exploring risk factors for TACO may guide preventive or therapeutic interventions, helping to further mitigate this transfusion complication.

Characterizing the epidemiology of postoperative transfusion-related acute lung injury.

Background:Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related death in the United States; however, it remains poorly characterized in surgical populations. To better inform perioperative transfusion practice, and to help mitigate perioperative TRALI, the authors aimed to better define its epidemiology before and after TRALI mitigation strategies were introduced. Methods:This retrospective cohort study examined outcomes of adult patients undergoing noncardiac surgery with general anesthesia who received intraoperative transfusions during 2004 (n = 1,817) and 2011 (n = 1,562). The demographics and clinical characteristics of transfusion recipients, blood transfusion descriptors, and combined TRALI/possible TRALI incidence rates were evaluated. Univariate analyses were used to compare associations between patient characteristics, transfusion details, and TRALI mitigation strategies with TRALI/possible TRALI incidence rates in a before-and-after study design. Results:The incidence of TRALI/possible TRALI was 1.3% (23 of 1,613) in 2004 versus 1.4% (22 of 1,562) in 2011 (P = 0.72), with comparable overall rates in males versus females (1.4% [23 of 1,613] vs. 1.2% [22 of 1,766]) (P = 0.65). Overall, thoracic (3.0% [4 of 133]), vascular (2.7% [10 of 375]), and transplant surgeries (2.2% [4 of 178]) carried the highest rates of TRALI/possible TRALI. Obstetric and gynecologic surgical patients had no TRALI episodes. TRALI/possible TRALI incidence increased with larger volumes of blood product transfused (P < 0.001). Conclusions:Perioperative TRALI/possible TRALI is more common than previously reported and its risk increases with greater volumes of blood component therapies. No significant reduction in the combined incidence of TRALI/possible TRALI occurred between 2004 and 2011, despite the introduction of TRALI mitigation strategies. Future efforts to identify specific risk factors for TRALI/possible TRALI in surgical populations may reduce the burden of this life-threatening complication.

Methemoglobinemia and hemolysis in a patient with G6PD deficiency treated with rasburicase.

A 52-year-old African American male was admitted to the hospital for high-dose chemotherapy for refractory aggressive multiple myeloma (MM). He had previously progressed through bortezomib/dexamethasone and lenalidomide therapy. The most recent bone marrow biopsy showed approximately 90% kappa light chain-restricted plasma cells with a high proliferative rate (3.3% cells in S-phase). Admission labs prior to starting any therapy (Table I) were significant for uric acid 16.1 mg/ dL (reference range, 3.7–8.0), creatinine 2.1 mg/dL (reference range, 0.8–1.3 and his baseline was 1.1), lactate dehydrogenase (LDH) 438 U/L (reference range, 122– 222), phosphorus 6.2 mg/dL (reference range, 2.5–4.5), hemoglobin 7.1 g/dL (reference range, 13.5–17.5), and IgG kappa monoclonal protein of 4.1 g/dL. On admission, baseline pulse oximetry at the bedside was normal at 95% O2 saturation (SpO2). Due to baseline renal insufficiency and anticipated tumor lysis, intravenous (IV) fluids were started immediately followed by 6 mg of rasburicase on Day 1. High-dose IV cyclophosphamide (1,500 mg/m) and 1,000 mg of methylprednisolone were administered in the early morning on Day 2. This patient presents with hyperuricemia and hyperphosphatemia with laboratory levels that meet Cairo–Bishop criteria of tumor lysis syndrome (TLS) even before chemotherapy was initiated [1,2]. In addition, he also has an acute kidney injury (AKI) secondary to TLS occurring in the setting of refractory MM as manifested by high tumor burden, high plasma cell proliferative rate, increased serum LDH, and a very high uric acid with AKI. Given the clinical features and baseline hyperuricemia and AKI, rasburicase should be administered to prevent worsening renal failure. A glucose-6-phosphatase dehydrogenase (G6PD) level is usually obtained in patients receiving rasburicase because rasburicase can induce hemolysis and cause methemoglobinemia in enzyme-deficient individuals. In our patient, the options were to give rasburicase or to provide prophylactic kidney dialysis without rasburicase. We proceeded with rasburicase given the need for immediate chemotherapy. On hospital Day 2, bedside pulse oximetry showed significant hypoxemia (SpO2 75%), triggering an emergency consultation with the critical care team. The patient was evaluated and found to be quite comfortable on room air with a respiratory rate of 16 per minute without the use of accessory muscles of respiration; lung, cardiac, and mucous membrane examinations were normal. An arterial blood gas (ABG) was performed and the arterial blood was noted to be brown in color. ABG showed pH 7.39, pO2 104 mmHg, pCO2 39 mmHg, HCO3 24 mmol/L and methemoglobin 12.9% (normal range, 0–1.5%). At this point, the care team discussed the use of IV methylene blue. Methemoglobinemia is one of the known side effects of rasburicase administration. In the setting of recent rasburicase administration, the low SpO2 with a normal physical examination in an asymptomatic patient makes the diagnosis of methemoglobinemia highly likely. There was no detectable blue skin color due to his African American ethnicity. ABG findings with the normal pO2 and increased methemoglobin confirmed the diagnosis. Rasburicase can induce hemolysis in G6PD-deficient patients. Moreover, G6PD deficient patients who develop methemoglobinemia should not be given methylene blue as it can also induce hemolysis. Immediate treatment with methylene blue was considered in our patient, but avoided given his relatively moderate degree of methemoglobinemia, asymptomatic condition, and his unknown G6PD status at that time on Day 2. Ascorbic acid administration is the alternative method of treatment. The patient was treated conservatively with ascorbic acid therapy 1,000 mg oral daily. The G6PD level returned deficient at 3.3 U/g Hb (normal, 8.8–13.4) and thus the patient did not receive methylene blue. Over the next 4 days, his methemoglobinemia resolved and his O2 saturation normalized (Fig. 1). Unfortunately, during this same time period, he developed progressive anemia requiring red blood cell support. Serum haptoglobin was normal at 69 mg/dL (reference range, 30–200) on Day 3 but became undetectable (<14) by Day 5. Bilirubin increased from 0.6 mg/dL on Day 2 to 3.6 mg/dL (reference range, 0.1–1.0 mg/dL) on Day 5; LDH increased from 438 U/L on Day 1 to 1,555 U/L on Day 5. The patient reported tea-colored urine. He was supported with a total of eight units of packed red blood cells over the next 4 days (Table I). The patient’s low G6PD level explains the moderate hemolysis that he developed after rasburicase administration. It is important to note that there was an hemolysis-free interval between the rasburicase administration and the first clinical and laboratory signs of hemolysis. This is typical and must be remembered or else hemolysis may be missed during a short hospital admission.

Platelets in the pathogenesis of acute respiratory distress syndrome

Platelets have an emerging and incompletely understood role in a myriad of host immune responses, extending their role well beyond regulating thrombosis. Acute respiratory distress syndrome is a complex disease process characterized by a range of pathophysiologic processes including oxidative stress, lung deformation, inflammation, and intravascular coagulation. The objective of this review is to summarize existing knowledge on platelets and their putative role in the development and resolution of lung injury.

Contrasting effect of different cardiothoracic operations on echocardiographic right ventricular long axis velocities, and implications for interpretation of post-operative values

Background Patients undergoing coronary artery bypass grafting (CABG) experience a reduction in right ventricular long axis velocities post surgery. Objectives We tested whether the phenomenon of right ventricular (RV) long axis velocity decline depends on the chest being opened fully by mid-line sternotomy, pericardial incision, or on the type of operation performed. Method By intraoperative transoesophageal echocardiography (TEE) we recorded serial right ventricular (RV) systolic pulse-wave tissue Doppler velocities during 6 types of elective procedure: 53 CABG surgery, 15 robotic-assisted minimally-invasive CABG (RCABG), 28 aortic valve replacement (AVR), 8 minimally-invasive aortic valve replacement (mini-AVR), 5 mediastinal mass excision, and 1 left atrial myxoma excision. Pre and post operative transthoracic echocardiography (TTE) were also conducted. Results Surgery without substantial opening of the pericardium did not significantly reduce RV systolic velocities (RCABG 13 ± 1.8 versus 12.4 ± 2.7 cm/s post; mini-AVR 11.9 ± 2.3 versus 11.1 ± 2.3 cm/s; mediastinal mass excision 13.9 ± 3.1 versus 13.8 ± 4 cm/s). In contrast, within 5 min of pericardial incision those whose surgery involved full opening of the pericardium had large reductions in RV velocities: 54 ± 11% decline with CABG (11.3 ± 1.9 to 5.1 ± 1.6 cm/s, p < 0.0001), 54 ± 5% with AVR (12.6 ± 1.4 to 5.7 ± 0.6 cm/s, p < 0.001) and 49% with left atrial myxoma excision (11.3 to 15.8 cm/s). This persisted immediately after pericardial opening to the end of surgery (61 ± 11%, p < 0.0001; 58 ± 7%, p < 0.0001; 59% respectively). Conclusions It is full opening of the pericardium, and not cardiac surgery in general, which causes RV long axis decline following cardiac surgery. The impact is immediate (within 5 min) and persistent.

Fifty Years of Research in ARDS.Is Acute Respiratory Distress Syndrome a Preventable Disease

Abstract Despite significant advances in our understanding and management of patients with acute respiratory distress syndrome (ARDS), the morbidity and mortality from ARDS remains high. Given the limited number of effective treatments for established ARDS, the strategic focus of ARDS research has shifted toward identifying patients with or at high risk of ARDS early in the course of the underlying illness, when strategies to reduce the development and progression of ARDS and associated organ failures can be systematically evaluated. In this review, we summarize the rationale, current evidence, and future directions in ARDS prevention.

Epidemiology of Acute Respiratory Distress Syndrome Following Hematopoietic Stem Cell Transplantation

Objectives:Pulmonary complications are common following hematopoietic stem cell transplantation. Numerous idiopathic post-transplantation pulmonary syndromes have been described. Patients at the severe end of this spectrum may present with hypoxemic respiratory failure and pulmonary infiltrates, meeting criteria for acute respiratory distress syndrome. The incidence and outcomes of acute respiratory distress syndrome in this setting are poorly characterized. Design:Retrospective cohort study. Setting:Mayo Clinic, Rochester, MN. Patients:Patients undergoing autologous and allogeneic hematopoietic stem cell transplantation between January 1, 2005, and December 31, 2012. Interventions:None. Measurements and Main Results:Patients were screened for acute respiratory distress syndrome development within 1 year of hematopoietic stem cell transplantation. Acute respiratory distress syndrome adjudication was performed in accordance with the 2012 Berlin criteria. In total, 133 cases of acute respiratory distress syndrome developed in 2,635 patients undergoing hematopoietic stem cell transplantation (5.0%). Acute respiratory distress syndrome developed in 75 patients (15.6%) undergoing allogeneic hematopoietic stem cell transplantation and 58 patients (2.7%) undergoing autologous hematopoietic stem cell transplantation. Median time to acute respiratory distress syndrome development was 55.4 days (interquartile range, 15.1–139 d) in allogeneic hematopoietic stem cell transplantation and 14.2 days (interquartile range, 10.5–124 d) in autologous hematopoietic stem cell transplantation. Twenty-eight-day mortality was 46.6%. At 12 months following hematopoietic stem cell transplantation, 89 patients (66.9%) who developed acute respiratory distress syndrome had died. Only 7 of 133 acute respiratory distress syndrome cases met criteria for engraftment syndrome and 15 for diffuse alveolar hemorrhage. Conclusions:Acute respiratory distress syndrome is a frequent complication following hematopoietic stem cell transplantation, dramatically influencing patient-important outcomes. Most cases of acute respiratory distress syndrome following hematopoietic stem cell transplantation do not meet criteria for a more specific post-transplantation pulmonary syndrome. These findings highlight the need to better understand the risk factors underlying acute respiratory distress syndrome in this population, thereby facilitating the development of effective prevention strategies.

Complication rates among peripherally inserted central venous catheters and centrally inserted central catheters in the medical intensive care unit

PURPOSE There are limited contemporary data describing the rates of catheter-related deep vein thrombosis (CRDVT) and central line-associated bloodstream infection for peripherally inserted central venous catheters (PICCs) and centrally inserted central venous catheters (CICCs) in the medical intensive care unit (ICU). METHODS We performed a retrospective cohort study of 200 PICCs (dual/triple lumen) and 200 CICCs (triple/quadruple lumen) placed in medical ICU adults at Mayo Rochester between 2012 and 2013. Central lines were followed from insertion time until hospital dismissal (primary analysis) or ICU discharge (secondary analysis). Symptomatic CRDVT was determined by Doppler ultrasound. Central line-associated bloodstream infection was defined according to federal reporting criteria. RESULTS During 1730 PICC days and 637 CICC days, the incidence of CRDVT when followed until hospital dismissal was 4% and 1% (4.6 and 3.1 per 1000 catheter-days), respectively, P = .055. When censored at the time of ICU dismissal, the rates were 2% and 1% (5.3 and 3.7 per 1000 catheter-days), P = .685. Only 1 central line-associated bloodstream infection occurred in a PICC following ICU dismissal, P > .999. CONCLUSIONS Thrombotic and infectious complications were uncommon following PICC and CICC insertion, with no significant difference in complication rates observed. Half of PICC DVTs occurred on the general floor, and like all central catheters placed in the ICU, PICCs should be aggressively discontinued when no longer absolutely needed.

Validation of Computerized Automatic Calculation of the Sequential Organ Failure Assessment Score

Purpose. To validate the use of a computer program for the automatic calculation of the sequential organ failure assessment (SOFA) score, as compared to the gold standard of manual chart review. Materials and Methods. Adult admissions (age > 18 years) to the medical ICU with a length of stay greater than 24 hours were studied in the setting of an academic tertiary referral center. A retrospective cross-sectional analysis was performed using a derivation cohort to compare automatic calculation of the SOFA score to the gold standard of manual chart review. After critical appraisal of sources of disagreement, another analysis was performed using an independent validation cohort. Then, a prospective observational analysis was performed using an implementation of this computer program in AWARE Dashboard, which is an existing real-time patient EMR system for use in the ICU. Results. Good agreement between the manual and automatic SOFA calculations was observed for both the derivation (N=94) and validation (N=268) cohorts: 0.02 ± 2.33 and 0.29 ± 1.75 points, respectively. These results were validated in AWARE (N=60). Conclusion. This EMR-based automatic tool accurately calculates SOFA scores and can facilitate ICU decisions without the need for manual data collection. This tool can also be employed in a real-time electronic environment.