Roland Henaine

The Ability of Stroke Volume Variations Obtained with Vigileo/FloTrac System to Monitor Fluid Responsiveness in Mechanically Ventilated Patients

BACKGROUND: Respiratory variations in arterial pulse pressure (&Dgr;PP) are accurate predictors of fluid responsiveness in mechanically ventilated patients. The aim of our study was to assess the ability of a novel algorithm for automatic estimation of stroke volume variation (SVV) to predict fluid responsiveness in mechanically ventilated patients. METHODS: We studied 25 patients referred for coronary artery bypass grafting. SVV was continuously displayed by the Vigileo/FloTrac system. All patients were under general anesthesia, mechanical ventilation and were also monitored with a pulmonary artery catheter. SVV and &Dgr;PP were recorded simultaneously before and after an intravascular volume expansion (VE) (500 mL hetastarch). Responders to VE were defined as patients whose cardiac index obtained using thermodilution increased by more than 15% after VE. RESULTS: Agreement between &Dgr;PP and SVV over the 50 pairs of collected data was −1.3% ± 2.8% (mean bias ± sd). Seventeen patients were responders to VE. A threshold &Dgr;PP value of 10% allowed discrimination of responders to VE with a sensitivity of 88% and a specificity of 87%. A threshold SVV value of 10% allowed discrimination of responders to VE with a sensitivity of 82% and a specificity of 88%. CONCLUSION: SVV predicts fluid responsiveness with an acceptable sensitivity and specificity and is also a potential surrogate for continuous monitoring of &Dgr;PP.

The ability of a novel algorithm for automatic estimation of the respiratory variations in arterial pulse pressure to monitor fluid responsiveness in the operating room.

BACKGROUND: Respiratory variations in arterial pulse pressure (&Dgr;PPman) are accurate predictors of fluid responsiveness in mechanically ventilated patients. However, they cannot be continuously monitored. In our study, we assessed the clinical utility of a novel algorithm for automatic estimation of &Dgr;PP (&Dgr;PPauto). METHODS: We studied 25 patients referred for coronary artery bypass grafting. &Dgr;PPauto was continuously displayed using a method based on automatic detection algorithms, kernel smoothing, and rank-order filters. All patients were under general anesthesia, mechanical ventilation, and were also monitored with a pulmonary artery catheter. &Dgr;PPman and &Dgr;PPauto were recorded simultaneously at eight steps during surgery including before and after intravascular volume expansion (500 mL hetastarch). Responders to volume expansion were defined as patients whose cardiac index increased by more than 15% after volume expansion. RESULTS: Agreement between &Dgr;PPman and &Dgr;PPauto over the 200 pairs of collected data was 0.7% ± 3.4% (mean bias ± sd). Seventeen patients were responders to volume expansion. A threshold &Dgr;PPman value of 12% allowed discrimination of responders to volume expansion with a sensitivity of 88% and a specificity of 100%. A threshold &Dgr;PPauto value of 10% allowed discrimination of responders to volume expansion with a sensitivity of 82% and a specificity of 88%. CONCLUSION: &Dgr;PPauto is strongly correlated to &Dgr;PPman is an accurate predictor of fluid responsiveness, and allows continuous monitoring of &Dgr;PP. This novel algorithm has potential clinical applications.

Effects of lack of pulsatility on pulmonary endothelial function in the Fontan circulation

OBJECTIVES Continuous flow in the Fontan circulation results in impairment of pulmonary artery endothelial function, increased pulmonary arterial resistance, and, potentially, late failure of Fontan circulation. We investigated the mechanisms of vascular remodeling and altered vascular reactivity associated with chronic privation of pulsatility on pulmonary vasculature. METHODS A total of 30 pigs were evenly distributed in 3 groups: 10 underwent a sham procedure (group I) and 20 underwent a cavopulmonary shunt between the superior vena cava and right pulmonary artery--10 with complete ligation of the proximal right pulmonary artery (group II, nonpulsatile) and 10 with partial ligation (group III, micropulsatile). At 3 months postoperatively, the in vivo hemodynamics, in vitro vasomotricity (concentration response curves on pulmonary artery isolated rings), and endothelial nitric oxide synthase protein level were assessed. A comparison between group and between the right and left lung in each group was performed. RESULTS Group II developed right pulmonary hypertension and increased right pulmonary resistance. Endothelial function was altered in group II, as reflected by a decrease in the vasodilation response to acetylcholine and ionophoric calcium but preservation of the nonendothelial-dependent response to sodium nitroprusside. Group III micropulsatility attenuated pulmonary hypertension but did not prevent impairment of the endothelial-dependant relaxation response. Right lung Western blotting revealed decreased endothelial nitric oxide synthase in group II (0.941 ± 0.149 vs sham 1.536 ± 0.222, P = .045) that was preserved in group III (1.275 ± 0.236, P = .39). CONCLUSIONS In a chronic model of unilateral cavopulmonary shunt, pulsatility loss resulted in an altered endothelial-dependant vasorelaxation response of the pulmonary arteries. Micropulsatility limited the effects of pulsatility loss. These results are of importance for potential therapies against pulmonary hypertension in the nonpulsatile Fontan circulation, by retaining accessory pulmonary flow or pharmaceutical modulation of nonendothelial-dependant pulmonary vasorelaxation.

Ability of the third-generation FloTrac/Vigileo software to track changes in cardiac output in cardiac surgery patients: a polar plot approach.

OBJECTIVE To evaluate the ability of the third-generation (3.01) of FloTrac/Vigileo monitor (Edwards Lifesciences, Irvine, CA) to follow variations in cardiac output (∆CO) using the new polar plot approach. DESIGN Prospective interventional study. SETTING Single hospital university study. PARTICIPANTS Twenty-five patients referred for cardiac surgery. INTERVENTIONS CO was measured simultaneously by 3 to 5 bolus thermodilution (COtd measurements), using a pulmonary artery catheter and by arterial pulse contour analysis, using the FloTrac/Vigileo (COvi). Data were collected at eight time points: before incision, after sternotomy, before and after protamine sulfate infusion, at the start of sternal closure, at the end of surgery, on arrival to intensive care unit, and after a standardized volume expansion with 500 mL of hetastarch 6%. MEASUREMENTS AND MAIN RESULTS One-hundred thirty-five pairs of CO data were collected; the mean bias of all CO measurements corrected for repeated measures was 0.2 L/min with limits of agreements of -3.3 L/min and +2.9 L/min. The percentage error was 66.5%. The polar plot analysis included 71 significant ∆CO and showed a mean polar angle of -3.4 degrees with 95% polar percentage error equivalent limits of -61 to 55; 69% of analysed data points fell within the 30-degree limits and provided a correct polar concordance rate. CONCLUSIONS Third-generation FloTrac/Vigileo software still lacks the accuracy to reliably detect changes in cardiac output (∆CO) in cardiac surgery. Improvements to FloTrac/Vigileo CO algorithm and software still are needed in this particular setting.

A new self-expanding aortic stent valve with annular fixation: in vitro haemodynamic assessment

OBJECTIVE Balloon-expandable stent valves require flow reduction during implantation (rapid pacing). The present study was designed to compare a self-expanding stent valve with annular fixation versus a balloon-expandable stent valve. METHODS Implantation of a new self-expanding stent valve with annular fixation (Symetis, Lausanne, Switzerland) was assessed versus balloon-expandable stent valve, in a modified Dynatek Dalta pulse duplicator (sealed port access to the ventricle for transapical route simulation), interfaced with a computer for digital readout, carrying a 25 mm porcine aortic valve. The cardiovascular simulator was programmed to mimic an elderly woman with aortic stenosis: 120/85 mmHg aortic pressure, 60 strokes/min (66.5 ml), 35% systole (2.8 l/min). RESULTS A total of 450 cardiac cycles was analysed. Stepwise expansion of the self-expanding stent valve with annular fixation (balloon-expandable stent valve) resulted in systolic ventricular increase from 120 to 121 mmHg (126 to 830+/-76 mmHg)*, and left ventricular outflow obstruction with mean transvalvular gradient of 11+/-1.5 mmHg (366+/-202 mmHg)*, systolic aortic pressure dropped distal to the valve from 121 to 64.5+/-2 mmHg (123 to 55+/-30 mmHg) N.S., and output collapsed to 1.9+/-0.06 l/min (0.71+/-0.37 l/min* (before complete obstruction)). No valve migration occurred in either group. (*=p<0.05). CONCLUSIONS Implantation of this new self-expanding stent valve with annular fixation has little impact on haemodynamics and has the potential for working heart implantation in vivo. Flow reduction (rapid pacing) is not necessary.

Sutureless pericardial repair of total anomalous pulmonary venous connection in patients with right atrial isomerism.

Surgical repair of total anomalous pulmonary venous connection (TAPVC) in patients with right atrial isomerism is associated with a significant risk of recurrent pulmonary venous obstruction (PVO). We evaluate the effect of sutureless repair to reduce the risk of recurrent PVO. Since November 2007, five patients, including three neonates, with right atrial isomerism underwent sutureless repair of TAPVC. The sutureless repair was used in three neonates as an initial procedure and in two infants as a procedure for postrepair PVO. Under deep hypothermic circulatory arrest or low flow cardiopulmonary bypass, pulmonary vein (PV) was incised as long as possible. The atrial wall was partially resected and anastomosed to the pericardial wall around the incised PV. There were no early deaths. No patients showed recurrence of PVO. There was one late death. Two patients underwent a bidirectional Glenn shunt after the sutureless repair. The pulmonary venous confluence was confirmed to be left open at the time of the Glenn surgery. The sutureless technique may be useful not only for postrepair PVO but also for non-operated TAPVC in neonates with right atrial isomerism.

Intraoperative Transesophageal Echocardiography Using a Miniaturized Transducer in a Neonate Undergoing Norwood Procedure for Hypoplastic Left Heart Syndrome

A 7-day–old neonate (weight, 2.7 kg; height, 48 cm) with hypoplastic left heart syndrome was referred to our institution for a Norwood stage I palliation procedure. In the small neonate, conventional transesophageal echocardiographic probe insertion and manipulation can induce hemodynamic instability or respiratory compromise. Therefore, the usual weight range for neonates and infants who can be safely imaged in the operating department with the use of currently available echocardiographic probes is >3 kg. Recently, a …

Resection of Secreting Cardiac Pheochromocytoma With and Without Cardiopulmonary Bypass

We report two cases of cardiac pheochromocytoma, the first with superior vena cava obstruction and the second involving the left atrium and extending to the posterior wall of the aorta. Both tumors were resected with disease-free margins, with and without the use of cardiopulmonary bypass, respectively. The patients remain asymptomatic at 8-year and 1-year follow-ups, respectively.

Subtle bacterial endocarditis due to Kingella kingae in an infant: a case report.

A 9-month-old infant presented with fever, dyspnoea, and a murmur. Echocardiography showed a mitral vegetation with significant regurgitation. Mitral valve plasty was performed on day 6, and was polymerase chain reaction positive for Kingella kingae. The cardiac outcome was favourable. This case illustrates a subtle presentation of K. kingae mitral valve infective endocarditis in a normal-cardaic infant, treated with early surgery, and the agent belonged to the HACEK (Haemophilus spp Actinobacillus actinomycetemcomitans, Capnocytophaga spp, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) group.

International normalized ratio self-testing and self-management: improving patient outcomes

Long term oral anti-coagulation with vitamin K antagonists is a risk factor of hemorrhagic or thromebomlic complications. Periodic laboratory testing of international normalized ratio (INR) and a subsequent dose adjustment are therefore mandatory. The use of home testing devices to measure INR has been suggested as a potential way to improve the comfort and compliance of the patients and their families, the frequency of monitoring and, finally, the management and safety of long-term oral anticoagulation. In pediatric patients, increased doses to obtain and maintain the therapeutic target INR, more frequent adjustments and INR testing, multiple medication, inconstant nutritional intake, difficult venepunctures, and the need to go to the laboratory for testing (interruption of school and parents’ work attendance) highlight those difficulties. After reviewing the most relevant published studies of self-testing and self-management of INR for adult patients and children on oral anticoagulation, it seems that these are valuable and effective strategies of INR control. Despite an unclear relationship between INR control and clinical effects, these self-strategies provide a better control of the anticoagulant effect, improve patients and their family quality of life, and are an appealing solution in term of cost-effectiveness. Structured education and knowledge evaluation by trained health care professionals is required for children, to be able to adjust their dose treatment safely and accurately. However, further data are necessary in order to best define those patients who might better benefit from this multidisciplinary approach.