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ABSTRACT: To compare measurements obtained by transesophageal echocardiography (TEE) and epicardial echocardiography (EE) for evaluation of the tricuspid valve (TV) and pulmonary valve (PV).
Prospective observational.
University hospital.
Patients undergoing elective coronary artery bypass grafting with or without aortic valve replacement.
After routine intraoperative TEE, EE was performed to compare measurements obtained by the 2 methods.
After institutional review board approval, 25 patients >18 years old were recruited. Biases with EE versus TEE for E and A waves were 11.9 cm/second (95% confidence interval [CI], 48.2 to -24.4) and 6.8 cm/second (95% CI, 28 to -15), respectively, and for E/A ratio was 0.08 (95% CI, 1.2 to -1). Pulmonary velocity bias was 57.94 cm/second (95% CI, 192.9 to -76.98), with higher values using EE. Bias for pulmonary trunk diameter was -0.31 cm (95% CI, 1.5 to -2.1). For quality of images, means were 2.4 (standard deviation [SD], 1.0) for EE and 2.3 (SD, 0.57) with TEE for TV and 2.4 (SD, 1.0) with EE and 2.5 (SD, 1.0) with TEE for PV. For the number of leaflets visualized, means were 2.2 (SD, 1.0) with EE and 2.5 (SD, 0.5) with TEE for TV and 2.5 (SD, 0.5) for EE and 1.3 (SD, 1.1) with TEE for PV.
There was good agreement for Doppler measurements across TVs; however, measurements across PVs were significantly higher with EE versus TEE. TV Doppler measurements were difficult to acquire even for surgeons experienced in epiaortic scanning.
Journal of cardiothoracic and vascular anesthesia 09/2011; 26(1):32-8. · 1.06 Impact Factor
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ABSTRACT: The acute respiratory distress syndrome (ARDS) arises from direct and indirect injury to the lungs and results in a life-threatening form of respiratory failure in a heterogeneous, critically ill patient population. Critical care technologies used to support patients with ARDS, including strategies for mechanical ventilation, have resulted in improved outcomes in the last decade. However, there is still a need for effective pharmacotherapies to treat ARDS, as mortality rates remain high. To date, no single pharmacotherapy has proven effective in decreasing mortality in adult patients with ARDS, although exogenous surfactant replacement has been shown to reduce mortality in the paediatric population with ARDS from direct causes. Several promising therapies are currently being investigated in preclinical and clinical trials for treatment of ARDS in its acute and subacute, exudative phases. These include exogenous surfactant therapy, beta(2)-adrenergic receptor agonists, antioxidants, immunomodulating agents and HMG-CoA reductase inhibitors (statins). Recent research has also focused on prevention of acute lung injury and acute respiratory distress in patients at risk. Drugs such as captopril, rosiglitazone and incyclinide (COL-3), a tetracycline derivative, have shown promising results in animal models, but have not yet been tested clinically. Further research is needed to discover therapies to treat ARDS in its late, fibroproliferative phase. Given the vast number of negative clinical trials to date, it is unlikely that a single pharmacotherapy will effectively treat all patients with ARDS from differing causes. Future randomized controlled trials should target specific, more homogeneous subgroups of patients for single or combination therapy.
Drugs 07/2010; 70(10):1255-82. · 4.23 Impact Factor
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ABSTRACT: The purpose of this study was to compare transvalvular flow velocities obtained by transesophageal echocardiography and epicardial echocardiography (EE) during aortic valve replacement (AVR).
Prospective observational study.
University hospital.
Patients undergoing AVR for aortic stenosis.
After institutional review board approval, 17 patients undergoing AVR consented. Deep transgastric (deep TG LAX) and transgastric long-axis (TG LAX) views and epicardial aortic valve long-axis views (S8 probe) were obtained on a SONOS 5500 (Phillips Medical Systems, Bothell, WA) before and after AVR. Transvalvular flow velocity and velocity time integral (VTI) were recorded via each technique. Measurements were made offline by 2 independent reviewers. Agreement between measurements made by different views was evaluated by using Bland-Altman analysis.
The epicardial probe was well tolerated. Quality images were obtained in all patients with TEE and 30 of 34 studies via epicardial scanning. The mean bias for peak velocities derived through EE and deep TG LAX was 96.3 cm/s (95% confidence interval [CI], 51.1-141.4) before AVR and 58 cm/s (95% CI, 32.4-83.7) after AVR. The mean bias for peak velocities between EE and TG LAX was 70 cm/s (95% CI, 31.1-108.9) before and 84.7 cm/s (95% CI, 55.6-113.7) after AVR. Similar results were obtained for VTI.
Peak transaortic valve velocities and VTI measured with epicardial echocardiography are higher in comparison to measurements via TEE in patients undergoing AVR. The precise role of epicardial echocardiography in the comprehensive echocardiographic examination of patients undergoing aortic valve replacement needs further evaluation.
Journal of cardiothoracic and vascular anesthesia 07/2009; 23(3):292-7. · 1.06 Impact Factor
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Ravi Taneja,
Gulshan Marwaha,
Prabhat Sinha,
Mackenzie Quantz,
Larry Stitt,
Rouchu Gao,
Seetha Subramanian,
Maureen Schaus,
Mike Keeney,
Ian Chin-Yee,
John Murkin
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ABSTRACT: Exposure to cardiopulmonary bypass (CPB) is associated with postoperative coagulopathy and hemorrhage. Recent literature indicates that heparin rebound occurs almost universally following cardiac surgery. We conducted this pilot study to evaluate if the presence of residual circulating heparin following cardiac surgery can be diagnosed by elevation of activated partial thromboplastin time (APTT).
After obtaining Research Ethics Board approval, blood samples from 30 patients receiving heparin for CPB were evaluated at the time of intensive care unit admission and 2, 4, and 6 hr thereafter. Activated clotting time, whole blood heparin concentration (Hepcon HMS Plus, Medtronic), anti-Xa levels, and APTT were measured at each time point. Samples with prolonged APTT were subjected to mechanistic studies with heparin adsorption and 1:1 mixing.
Anti-Xa was elevated in 52 of the 120 blood samples (0.08 +/- 0.08 U . mL(-1), mean +/- SD). APTT was elevated in 49 (40.8%) samples with an average of 51.4 +/- 31.9 sec. At all time points, the APTT correlated poorly with anti-Xa levels with correlation coefficients ranging from -0.26 to -0.05. Mean APTT was modestly, but not significantly, associated with total dose of protamine with r = 0.34 (CI: -0.03, 0.62). After 1:1 mixing studies, APTT returned to normal in most (82%) samples tested.
Circulating residual heparin is commonly presented following cardiac surgery and does not correlate with APTT. Considering that mixing studies normalize APTT in most samples, elevated APTT following CPB may reflect deficiency of coagulation factors or presence of a coagulation inhibitor such as protamine. Further studies are required to confirm this observation.
Canadian Anaesthetists? Society Journal 06/2009; 56(7):489-96. · 2.31 Impact Factor
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ABSTRACT: To determine which strategies are currently used for (anti)coagulation management and blood conservation during cardiac surgery in Canada.
Institutional survey.
University hospital.
All sites performing cardiac surgery in Canada.
None.
The response rate was 85%. Anticoagulation with heparin is monitored routinely through the activated coagulation time (ACT). Less than 10% of centers use heparin concentrations (Hepcon HMS, Medtronic), thromboelastography, or other point-of-care tests perioperatively. Eighty percent of centers routinely use tranexamic acid as the primary antifibrinolytic agent; however aprotinin until recently, was used more commonly for patients at increased risk for bleeding. Retrograde autologous prime is commonly used (62%); however, cell savers are uncommon for routine patients undergoing cardiac surgery (29%). Although most hospitals use a hematocrit of 20% to 21% for transfusing red blood cells, more than 50% of intensive care units do not have written guidelines for the administration of protamine, fresh frozen plasma, platelets, or factor VIIa. At least one third of centers do not audit their transfusion practices regularly.
The majority of Canadian institutions do not use point-of-care tests other than ACT. Most institutions do not have algorithms for management of bleeding following cardiac surgery and at least 30% do not monitor their transfusion practice perioperatively. Cardiac surgery patients in Canada may benefit from a standardized approach to blood conservation in the perioperative period.
Journal of cardiothoracic and vascular anesthesia 11/2008; 22(5):662-9. · 1.06 Impact Factor
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ABSTRACT: Patients with sepsis commonly develop leukocytosis, which is presumed to reflect a host response to infection. Effective phagocytosis by neutrophils is crucial in the clearance of invading microbes. However, efficacy of phagocytosis in sepsis is controversial. We hypothesized that host phagocytic capacity in sepsis can be affected by immature neutrophils that are released into the circulation. Circulating neutrophils were evaluated in 16 patients with severe sepsis and 5 healthy donors. Immature neutrophils were identified by the cell morphology. Phagocytosis was evaluated by micromanipulation technique and simultaneous cytosolic-free Ca2+ imaging. Leukocytosis was present in 12 of 16 patients. Nine of the 12 patients with leukocytosis and 3 of 4 patients with normal white blood cell counts had increased circulating immature neutrophils (mean, 39.3% +/- 20.7%; normal <or=5%). Quantification of the phagocytic activity revealed a significantly reduced phagocytic index of immature neutrophils as compared with mature neutrophils from both sepsis patients and healthy donors (25% +/- 5% vs. 69% +/- 8% and 42% +/- 6%; P < 0.05). As compared with mature neutrophils, the number of internalized zymosan particles within immature neutrophils was also significantly lower. Mature neutrophils from patients and healthy donors displayed a single rapid transient Ca signal during phagocytosis in contrast with weak signals from immature neutrophils. Our preliminary results show that phagocytic capacity of immature neutrophils is lower as compared with mature neutrophils. An increase in immature neutrophils in severe sepsis may undermine the overall phagocytic efficacy of a host despite observed leukocytosis.
Shock (Augusta, Ga.) 05/2008; 30(6):618-22. · 2.87 Impact Factor
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ABSTRACT: The resolution of neutrophil (PMN)-mediated inflammation occurs through the apoptosis, or programmed cell death, of the neutrophil. PMN apoptosis is inhibited by a variety of inflammatory stimuli; moreover, PMN from critically ill septic patients show profoundly delayed rates of apoptosis in vitro. Since apoptosis is effected through the activity of intracellular cysteine proteases (caspases), we evaluated caspase expression and activity in neutrophils from septic patients and compared them with caspase expression and activity of resting or lipopolysaccharide-activated neutrophils from healthy volunteers.
Prospective observational cohort study.
Tertiary level intensive care unit and associated research laboratory.
Thirty-six intensive care unit patients with sepsis; ten healthy laboratory controls.
Collection of up to 10 mL of whole blood for in vitro study of rates of apoptosis, expression and activity of caspases-1, -3, and -9, activation of nuclear factor-kappaB, and change in mitochondrial transmembrane potential.
Following 24 hrs of in vitro culture, 52 +/- 7.8% of control neutrophils, but only 29 +/- 5.4% of lipopolysaccharide-stimulated (1 microg/mL) PMN, showed nuclear changes of apoptosis. Only 6.2 +/- 1.1% of neutrophils from septic patients were apoptotic after 24 hrs. Significant nuclear translocation of nuclear factor-kappaB was evident in septic PMN, and inhibition of apoptosis was partially abrogated by prevention of nuclear factor-kappaB dissociation with pyrrolidine dithiocarbamate. Caspase-3 transcription and catalytic activity were significantly reduced in both patients' and lipopolysaccharide-treated PMN; caspase-1 transcription and activity were increased by lipopolysaccharide but reduced in septic patients. In contrast, caspase-9 transcription and activity were reduced in septic patients but not in lipopolysaccharide-treated PMN. Decreased caspase-9 activity was associated with sustained maintenance of mitochondrial transmembrane potential and reduced translocation of cytochrome c from the mitochondria to the cytosol.
Apoptosis of circulating neutrophils from patients with clinical sepsis is profoundly suppressed, through a mechanism that involves activation of nuclear factor-kappaB that is associated with reduced activity of caspases-9 and -3 and maintenance of mitochondrial transmembrane potential and that differs in important respects from the inhibitory effects seen following the exposure of healthy neutrophils to inflammatory stimuli.
Critical Care Medicine 08/2004; 32(7):1460-9. · 6.33 Impact Factor
