Sergey Preisman

Assessing fluid-responsiveness by a standardized ventilatory maneuver : The respiratory systolic variation test

Respiratory-induced changes in arterial blood pressure predict fluid responsiveness. However, the accuracy of these variables is affected by the preset tidal volume and by the early inspiratory increase in arterial blood pressure. We have therefore calculated the slope produced by the minimal systolic blood pressures (plotted against the respective airway pressures) during a ventilatory maneuver consisting of four incremental, successive, pressure-controlled breaths, termed the Respiratory Systolic Variation Test (RSVT). In 14 ventilated patients, after major vascular surgery, the slope of the RSVT decreased significantly after intravascular fluid administration and correlated with the end-diastolic area and with changes in cardiac output better than filling pressures. This preliminary study suggests that a standardized ventilatory maneuver may be useful in guiding fluid therapy in ventilated patients.

Modified thromboelastography evaluation of platelet dysfunction in patients undergoing coronary artery surgery.

OBJECTIVE Anti-platelet therapy is associated with increased perioperative bleeding. Although current guidelines call for its caessation 5-10 days prior to cardiac surgery, this could constitute an increased risk of preoperative myocardial infarction. The optimal safe period from discontinuation of anti-platelet therapy to surgery is as yet unknown for the individual patient. We investigated whether preoperative thromboelastography (TEG) with platelet mapping could predict bleeding tendency in patients (on recent anti-platelet therapy) undergoing coronary artery bypass grafting (CABG). METHODS We prospectively evaluated 59 patients on aspirin and clopidogrel therapy who underwent CABG. Of them, 25 patients received aspirin alone. TEG with platelet mapping was performed immediately prior to surgery in all 59 patients. RESULTS During the first 24h post-surgery, 9/59 patients bled excessively (1216 + or - 310 ml in excessive bleeding vs 576 + or - 155 ml in non-bleeding patients). Of the patients bled excessively, eight received clopidogrel treatment prior to surgery. However, 26 of the remaining 34 patients receiving clopidogrel did not bleed significantly. Clopidogrel-induced platelet dysfunction diagnosed by platelet mapping discerned between patients who demonstrated excessive bleeding and those who did not (78% - sensitivity, 84% - specificity, p=0.004). Aspirin-induced platelet dysfunction did not reflect a bleeding tendency. Of all patients, 85% did not respond to a standard dose of clopidogrel, whereas 44% did not respond to aspirin. CONCLUSIONS TEG with platelet mapping is able to predict excessive postoperative blood loss among patients who underwent CABG and recent anti-platelet therapy. The prevalence of non-responsiveness to anti-platelet therapy, including clopidogrel, is higher in patients undergoing coronary artery bypass grafting than in the general population. In this study, aspirin-induced platelet dysfunction did not influence postoperative blood loss.

Minimally Invasive Congenital Cardiac Surgery Through Right Anterior Minithoracotomy Approach

BACKGROUND Median sternotomy has been the conventional approach for correction of congenital cardiac defects despite poor cosmetic results at times. Right anterior minithoracotomy was, therefore, assessed as an alternative procedure with a better cosmetic outcome. METHODS From October 2002 through February 2007, 75 patients underwent correction of congenital cardiac malformations with the use of cardiopulmonary bypass through right anterior minithoracotomy involving a short incision through the fifth intercostal space and the minimally invasive cannulation. Of them, 18 patients were infants, 42 were children, and 15 were adult. The average age was 9.26 +/- 14.1 years (range, 1.2 to 56). The average weight was 19.59 +/- 24.3 kg (range, 8.5 to 118 kg). The corrected defects included atrial septal defect type II, sinus venosus atrial septal defect with partial anomalous pulmonary venous drainage, atrial component of atrioventricular septal defect, perimembranous ventricular septal defects with patent foramen ovale, mitral valve repair (complex), repair of cleft mitral valve, cor triatum atrial septal defect, repair of double-chambered right ventricle and extraction of atrial septal defect closure device. Skin incisions were as long as 5 cm. RESULTS There was no operative or late mortality or major morbidity. The mean cardiopulmonary bypass time was 58.67 +/- 35.11 minutes (range, 32 to 263). Sixty-five patients were extubated in the operating room; the remaining 10 patients were extubated within 4 hours. Cosmetic result was very satisfactory in all patients. Two adult patients complained of some right chest musculoskeletal discomfort. CONCLUSIONS The right anterior minithoracotomy incision is a safe and effective alternative to a median sternotomy for correction of congenital heart defects. Cosmetic results are highly satisfactory.

A randomized trial of outcomes of anesthetic management directed to very early extubation after cardiac surgery in children.

OBJECTIVES Intraoperative management directed to early extubation of children undergoing cardiac surgery has been suggested as a viable alternative to prolonged postoperative mechanical ventilation. The authors evaluated the safety and efficacy of this approach in a randomized prospective trial. DESIGN A prospective randomized observational study. SETTING A single university-affiliated hospital. PARTICIPANTS One hundred consecutive pediatric patients (age 1 month-15 years, weight 3.0-51 kg) requiring cardiac surgery. Patients younger than 1 month of age and those requiring mechanical ventilation before the operation were considered ineligible for the study. INTERVENTIONS Patients were randomly allocated to a group with anesthetic management and extubation in the operating room (early group [EG]) and a group with elective prolonged mechanical ventilation (control group [CG]). MEASUREMENTS AND MAIN RESULTS A difference in outcome as reflected by the pediatric intensive care unit (PICU) and hospital lengths of stay and postoperative morbidity and mortality was analyzed. A separate analysis was performed in children younger than 3 years old. The extubation time in the CG was 25.0 +/- 26.9 hours. No differences in mortality, the need for re-exploration for bleeding, the need for reintubation, the incidence of abnormal chest radiographic findings, or cardiac and septic complications between groups were found. PICU and postoperative hospital lengths of stay were significantly shorter in patients in the EG (3.3 +/- 1.9 days in the EG v 5.8 +/- 4.1 in the CG, p < 0.001, and 7.4 +/- 2.9 days in the EG v 11.2 +/- 6.8 days in the CG, p = 0.009). CONCLUSIONS In children undergoing cardiac surgery, anesthetic management with early cessation of mechanical ventilation appears to be safe and decreases hospital and PICU length of stay. However, because the size of the study did not allow for the detection of possible differences in perioperative mortality, only a large multicenter study may provide a definite answer to this question. The present study may be treated as a pilot for such a trial.

Quality of mitral valve repair: Median sternotomy versus port-access approach

OBJECTIVES We sought to compare early and late clinical and echocardiographic outcomes of patients undergoing minimally invasive mitral valve repair by means of the port-access and median sternotomy approaches. METHODS Between 2000 and 2009, 503 patients had mitral valve repair, of whom 143 underwent surgical intervention for isolated posterior leaflet pathology: 61 through port access and 82 through median sternotomy. The port-access group had better preoperative New York Heart Association functional class (P = .007) and a higher rate of elective cases (97% vs 87%, P = .037). Other preoperative characteristics were similar between the groups, including mitral valve pathology and repair techniques. RESULTS Operative, bypass, and clamp times were significantly longer in the port-access group. Mean hospital stay was 5.3 +/- 2.5 days in the port-access group versus 5.7 +/- 2.5 days in the median sternotomy group (P = .4). Early postoperative echocardiographic analysis showed that most patients in both groups had none or trivial mitral regurgitation and none of the patients had greater than grade 2 mitral regurgitation. Follow-up extended for up to 100 months (mean, 34 +/- 24 months). New York Heart Association class improved in both groups (P = .394). Freedom from reoperation was 97% and 95% in the port-access and median sternotomy groups, respectively. Late echocardiographic analysis revealed that 82% (49/60) in the port-access group and 91% (73/80) in the median sternotomy group were free from moderate or severe mitral regurgitation (P = .11). CONCLUSIONS In isolated posterior mitral valve pathology, quality of mitral valve repair with the port-access approach can compare with that with the conventional median sternotomy approach.

Mitochondrial function and tissue vitality: bench-to-bedside real-time optical monitoring system

BACKGROUND The involvement of mitochondria in pathological states, such as neurodegenerative diseases, sepsis, stroke, and cancer, are well documented. Monitoring of nicotinamide adenine dinucleotide (NADH) fluorescence in vivo as an intracellular oxygen indicator was established in 1950 to 1970 by Britton Chance and collaborators. We use a multiparametric monitoring system enabling assessment of tissue vitality. In order to use this technology in clinical practice, the commercial developed device, the CritiView (CRV), is tested in animal models as well as in patients. METHODS AND RESULTS The new CRV enables the optical monitoring of four different parameters, representing the energy balance of various tissues in vivo. Mitochondrial NADH is measured by surface fluorometry/reflectometry. In addition, tissue microcirculatory blood flow, tissue reflectance and oxygenation are measured as well. The device is tested both in vitro and in vivo in a small animal model and in preliminary clinical trials in patients undergoing vascular or open heart surgery. In patients, the monitoring is started immediately after the insertion of a three-way Foley catheter (urine collection) to the patient and is stopped when the patient is discharged from the operating room. The results show that monitoring the urethral wall vitality provides information in correlation to the surgical procedure performed.

Adult Respiratory Distress Syndrome Following Cardiac Surgery

Severe lung injury with the development of acute respiratory distress syndrome (ARDS) is a serious complication of cardiac surgery. The aim of this study was to determine the incidence, risk factors, and mortality of ARDS following cardiac surgery.

Compression of the pulmonary artery during transesophageal echocardiography in a pediatric cardiac patient

IMPLICATIONS Hemodynamic compromise caused by the insertion of the probe for transesophageal echocardiography in a patient with severe stenosis of the main pulmonary artery is reported for the first time. The first symptom of the impending problem was a rapid decrease of end-tidal CO(2).

Evaluation of the impact of a quality improvement program and intensivist-directed ICU team on mortality after cardiac surgery.

OBJECTIVE Quality improvement is an important pursuit for critical care teams. DESIGN The authors performed an observational cohort study with historic control. SETTING Eight-bed cardiac surgery ICU in a tertiary university hospital. PARTICIPANTS A total of 4,866 patients undergoing cardiac surgery over a 6-year period between January 2005 and December 2010. INTERVENTIONS In this study, the influence of the introduction of a quality improvement program under the supervision of a newly appointed intensivist on patient outcomes after cardiac surgery was evaluated. Patients were further divided into three 2-year periods: Period I, 2005-2006, before appointment of an intensivist; Period II, 2007-2008, after appointment of an intensivist and initial introduction of a quality improvement program; and Period III, 2009-2010, after implementation of the program and introduction of Critical Care Information Systems. MEASUREMENTS AND MAIN RESULTS There were 1,633, 1,690, and 1,543 patients in each period, respectively. There was no significant difference in the severity of patient illness between the groups. Unadjusted in-hospital mortality decreased from 6.37% (104 patients) in Period I to 4.32% (73 patients) and 3.3% (51 patients) in Periods II and III, respectively (p< 0.01). CONCLUSIONS Appointment of an intensivist-directed team model and introduction of quality improvement interventions were associated with decreased mortality after cardiac surgery.

Evaluation of the CritiView in pig model of abdominal aortic occlusion and graded hemorrhage

We hypothesize that in the presence of reduced oxygen delivery and extraction, blood flow will be redistributed in order to protect the most vital organs (e.g., brain and heart) by increasing their regional blood flow, while O2 delivery to the less vital organs (e.g., GI tract or urethral wall) will diminish. Evaluation of mitochondrial function in vivo could be done by monitoring the oxidation reduction state of the respiratory chain. Thus, the NADH redox state of less vital organs could serve as an indicator of overall O2 imbalance as well as an endpoint of resuscitation. We have therefore tested, in a pig model, a new medical device providing real time data on NADH redox state and tissue blood flow- TBF This device contains a modified three way Foley catheter with a fiber optic probe which connects the measurement unit to the tested tissue. Female pigs underwent graded hemorrhage (GH) or Aortic clamping (AC). The main effects of GH started when blood volume decreased by 30%. At 40% blood loss, minimal levels of TBF were correlated to the maximal NADH levels. The values of the 2 parameters returned to baseline after retransfusion of the shed blood. Aortic clamping led to significant decrease in TBF while NADH levels increased. After aortic declamping the parameters recovered to normal values. Due to the short length of the urethra in female pigs and the instable contact between the probe and the tissue, inconsistency of the responses was observed. Our preliminary results show that the CritiView may be a useful tool for the detection of body O2 imbalance.