Normothermic cardiopulmonary bypass and cardioplegia reduce inotropic requirements and creatine kinase-MB after coronary artery bypass graft surgery

Purpose To determine whether normothermic cardiopulmonary bypass (CPB) and cardioplegia preserve myocardial function, reduce inotropic requirements, and reduce markers of myocardial ischemia following coronary artery bypass graft surgery (CABG). Methods We retrospectively reviewed the charts of 171 consecutive patients undergoing elective CABG by a single surgeon from April 1994 to December 1995. Hypothermic CPB with intermittent cold cardioplegia was used in 83 patients and normothermic CPB with intermittent warm cardioplegia in 88 patients. Demographic, surgical, hemodynamic, and inotropic requirements and laboratory data were reviewed. Results The duration of CPB was significantly shorter in the normothermic group (113±27vs 90±21 min;P<0.0001). After CPB the cardiac index was similar between groups, but significantly larger doses of both dopamine and dobutamine were required (8vs 5μg·kg⁻¹·min⁻¹,P<0.0001), and significantly more patients required norepinephrine administration in the hypothermic group (18%vs 6%;P=0.01). Postoperative peak values of creatine kinase MB fraction (CK-MB) were significantly lower in the normothermic group (80±60vs 55±54 IU·I⁻¹;P<0.0001). Conclusion Normothermic CPB and cardioplegia reduce inotropic requirements and CK-MB following CABG.     

Cystatin C: influence of perfusion and myocardial injury on early (<24 h) renal function after pediatric cardiac surgery

Background: Cardiopulmonary bypass (CPB)‐associated renal dysfunction following cardiac surgery is well recognized. In patients with renal disease, cystatin C has emerged as a new biomarker which in contrast to creatinine (Cr) is sensitive to minor changes in glomerular filtration rate (GFR). Aim: We utilized cystatin C to investigate the association of CPB perfusion parameters with acute renal injury after pediatric cardiac surgery. Methods: Twenty children, aged 4–58 months (AVSD, n = 7; VSD, n = 9; and ASD, n = 4), were prospectively studied. Glomerular filtration rate was quantified postoperatively by creatinine clearance (first and second 12‐h periods; CrCl_0–12 and CrCl_12–24). Serum cystatin C and Cr were measured preoperatively and on days 0–3. Recorded CPB parameters included bypass duration (BP), perfusion pressure (PP), lowest pump flow (Q_min), lowest hematocrit, and corresponding lowest oxygen delivery (DO_{2 min}). Myocardial injury was determined by troponin‐I. Results: Postoperatively, GFR remained unchanged (CrCl_0–12 63.6 ± 37.0 vs CrCl_12–24 65.1 ± 27.5; P = 0.51) and only correlated with cystatin C (CrCl_0–12 vs cystatin C_Day0 [r = 0.58, P = 0.018] and Cr_Day0 [r = 0.09, P = 0.735]). Cr and cystatin C increased postoperatively to peak on days 2 and 3, respectively (Cr_PreOp 31 ± 6.9 vs Cr_Day2 36.9 ± 12.2, P = 0.03; cystatin C_Day0 0.83 ± 0.27 vs cystatin C_Day3 1.45 ± 0.53, P = 0.02). Increased cystatin C was significantly associated with BP (P = 0.001), mean PP (P = 0.029), Q_min (P = 0.005), troponin‐I (P < 0.001), and DO_2min <300 ml·min^?1·m^?2 (P = 0.007). Receiver–operator cutoff >1.044 mg·l^?1 for cystatin C exhibited 100% sensitivity and 67% specificity for detecting renal dysfunction, defined as GFR <55 ml·min^?1·1.73 m^?2. Conclusions: Cystatin C is a sensitive marker of early renal dysfunction following pediatric heart surgery. Variations in bypass parameters, myocardial injury, and ultimately critical oxygen delivery are significantly associated with the degree of renal impairment.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Pulmonary gas exchange effects by nitroglycerin,dopamine and dobutamine during one-lung ventilation in man

The effects of nitroglycerin, dopamine and dobutamine on pulmonary gas exchange were determined in 21 adult patients during two-lung and one-lung ventilation. Nitroglycerin, in I μg·kg^?1·min^?1, decreased cardiac index (CI) andPaO₂ during both two-and one-lung ventilation, and increased in Qs/Qt during one-lung ventilation. There were no significant changes in the measured variables during infusion of dopamine, 5 μg·kg^?1·min^?1. Dobutamine, 5μg·kg^?1·min^?1, increased Cl and PaO₂ did not change during two-lung ventilation. During one-lung ventilation, PaO₂ increased from (mean value ±SD) 168 ± 46 to 201 ± 52 mmHg (P < 0.01) with dobutamine infusion. Qs/Qt decreased from 29.2 ± 7.0 to 26.0 ± 6.2 per cent (P < 0.05) without any change in pulmonary vascular resistance index during one-lung ventilation. We conclude that dobutamine has advantages over dopamine and nitroglycerin during one-lung ventilation.     

Single-lung ventilation with carbon dioxide hemipneumothorax: hemodynamic and respiratory effects in piglets

Objectives: Video‐assisted thoracoscopic surgery (VATS) has become a standard procedure in pediatric surgery. To facilitate surgical access, the dependent lung has to collapse using intrathoracic carbon dioxide insufflation and/or single‐lung ventilation. These procedures can induce hemodynamic deteriorations in adults. The potential impacts of single‐lung ventilation in combination with capnothorax on hemodynamics in infants have never been studied before. Aim: We conducted a randomized experimental study focusing on hemodynamic and respiratory changes during single‐lung ventilation with or without capnothorax in a pediatric animal model. Methods: Twelve piglets were randomly assigned to receive single‐lung ventilation with (SLV‐CO₂) or without (SLV) capnothorax with an insufflation pressure of 5 mmHg for a period of two hours. Before, during, and after single‐lung ventilation, hemodynamic and respiratory parameters were measured. Results: Although mean arterial pressure remained stable during the course of the study and no critical incidents were monitored, cardiac index (CI) decreased significantly with SLV‐CO₂ (baseline 3.6 ± 1.6 l·min^?1·m^?2 vs 2.9 ± 1.1 l·min^?1·m^?2 at 120 min, P < 0.05). Furthermore, global end‐diastolic volume and intrathoracic blood volume (ITBV) decreased as well significantly with SLV‐CO₂, causing a significant between‐group difference in ITBV (P < 0.05). Conclusions: Despite a decrease in CI and preload parameters, the combination of single‐lung ventilation and low‐pressure capnothorax was well tolerated in piglets and could justify further clinical studies to be performed in infants and children focusing on hemodynamic and respiratory changes during VATS.     

Haemodynamic changes in children with portal hypertension during the postoperative period

The cardiovascular changes following portosystemic shunt surgery (PSSS) in 33 children with extrahepatic portal hypertension (EPH) were studied to determine if portosystemic shunt surgery had any influence on the cardiovascular state. Haemodynamic data were obtained using two-dimensional and M-mode echocardiography, pulsed-wave Doppler and direct invasive techniques. Postoperatively all patients developed a hyperdynamic state, associated with an increase in cardiac index (CI), heart rate (HR) and a decrease in systemic vascular resistance index (SVRI). In 16 patients (group I), who preoperatively exhibited a hyperdynamic state accompanied by pulmonary hypertension, postoperative studies found an increase in acceleration time to ejection time ratio (AT/ET) in the pulmonary artery from 0.32 ± 0.05 (mean ± SEM) to 0.43±0.01; P < 0.01. Nine patients (group II) who were normodynamic preoperatively developed pulmonary hypertension and right ventricular (RV) dysfunction postoperatively: decrease in AT/ET from 0.42 ± 0.02 (mean ± SEM) to 0.32 ± 0.01; P < 0.01 and an increase in maximal peak pulmonary artery velocity to acceleration time ratio (Vmax/AT) from 702.56 ± 69.10 (mean ± SEM) to 1127 ± 105.30 cm·sec^-2; P < 0.01. In eight patients (group III) who were normodynamic preoperatively and were treated with dobutamine infusions at a rate of 5 μg·kg^-1·min^-1 postoperatively, the CI was found to increase from 5.28 ± 1.1 (mean ± SEM) to 7.97 ± 1.64 L·min^-1·m^-2; P < 0.01, left ventricular ejection fraction (LVEF) from 69.0 ± 4.1 (mean ± SEM) to 81.0 ± 2.9%; P < 0.01 and AT/ET from 0.37 ± 0.04 (mean ± SEM) to 0.44 ± 0.03; P < 0.01. Hence, dobutamine infusion at a dose of 5 μg·kg^-1·min^-1 can markedly increase cardiac performance and prevent pulmonary hypertension and RV dysfunction in children with EPH during the postoperative period.     

Arrhythmogenic potential of dopexamine hydrochloride during halothane anaesthesia in dogs

Dopexamine hydrochloride (Dopacard®) is the novel synthetic catecholamine designed for use in the acute management of a low cardiac output status. In addition to dopaminergic receptor stimulation, dopexamine hydrochloride is a potent β₂ adrenoreceptor agonist with negligible direct β₁ and no alpha adrenergic effect. The objective of this study was to compare the arrhythmogenic effects of dopexamine hydrochloride and dopamine in dogs anaesthetized with halothane (1.2 MAC). The starting dose for dopexamine hydrochloride was 3.5 μg · kg^?1 min^?1 and for dopamine was 5 μg · kg^?1 min^?1. Concentrations of the drugs were increased until four or more premature ventricular contractions within 15 seconds were produced. All dogs developed ventricular tachycardia when dopamine was administered in concentrations ranging between 18–20 μg · kg^?1 · min^?1. Unlike dopamine, dopexamine hydrochloride even at concentrations as high as 50 μg · kg^?1· min^?1 did not induce any atrial or ventricular ectopic beats. Lack of β_-1 and alpha adrenergic agonist effects is a likely explanation for low arrhythmogenicity of dopexamine hydrochloride. Both drugs increase cardiac output; dopexamine hydrochloride primarily by a dose-related increase in heart rate and increased aflerload. At the maximal concentration dopexamine hydrochloride increased heart rate from 114 to 150 beat · min^?1, mean arterial pressure decreased from 81 mmHg to 45 mmHg and SVR decreased from 2418 to 962 dyne · sec^?1cm^?5. Myocardial contractility increased only moderately, as evaluated by dP/dt, which increased from 1290 to 1696 mmHg · sec^?1. Dopamine had a more marked inotropic effect: the dP/dt increased, at the maximal concentration, from 1480 to 2570 mmHg · sec^?1. Dopamine also produced vasoconstriction: SVR increased from 2325 to 2683 dyne · sec · cm^?5 and mean arterial pressure from 86 mmHg to 110 mmHg. In conclusion, dopexamine hydrochloride is less arrhythmogenic than dopamine, has less of an inotropic effect, and a greater effect on aflerload.     

Auswirkungen von Dopexamin Transpulmonales Shuntvolumen bei thorax- chirurgischen Eingriffen mit Ein-Lungen-Beatmung

Objective: To study the influence of dopexamine on pulmonary shunt and hypoxic pulmonary vasoconstriction during major thoracic surgery with one-lung ventilation (OLV). Design: Prospective, randomised, placebo-controlled study. Setting: University hospital. Patients: Twenty adult patients undergoing elective pulmonary resection. Anaesthesia: General anaesthesia was performed using propofol, fentanyl, N₂O and vecuronium.Volume-controlled ventilation was performed to maintain normocapnia over the whole investigation period. During OLV, the tidal volume was reduced and the respiratory rate was increased to avoid a peak airway pressure exceeding 40 cm H₂O. Furthermore the FiO₂ was increased to 1,0 and the external PEEP was removed during OLV. Interventions: The patients received either dopexamine at 2 µg/kg/min (group A, n=10) or 0,9% saline as control (group B, n=10) after assessing the baseline values. Measurement and results: The following cardiorespiratory variables were recorded: Heart rate, mean arterial pressure and mean pulmonary arterial pressure. Cardiac output was measured by thermodilution using a continuous cardiac output thermodilution catheter. Arterial and mixed venous blood gas analysis were measured from simultaneously drawn samples. Cardiac index (CI), systemic vascular resistance index, pulmonary vascular resistance index, oxygen delivery index (DO₂I), oxygen consumption index and the venous admixture were calculated using standard formula. Furthermore, pressure-flow-curves were constructed to analyse flow independent changes in the pulmonary vascular resistance. Data were recorded at the following times: After induction of anaesthesia in stable haemodynamics during two-lung ventilation (baseline values, T0), intraoperatively during one-lung ventilation (T1) and postoperatively after re-establishing two-lung ventilation (T2). Patients characteristics, data from the preoperative lung function testing and surgical procedures did not differ significantly between the groups. CI increased in the dopexamine group from 2,5±1,2 l·min^?1·m^?2 (T0) to 3,6±0,9 l·min^?1·m^?2 (T1) and 4,0±1,3 l·min^?1· m^?2 (T2). The course of the intrapulmonary right-to-left shunting did not differ between the groups. In the dopexamine-treated group the DO₂I increased from 430±143 ml·min·m^?2 (T0) to 652±255 ml·min·m^?2 (T1) and 653±207 ml·min·m^?2 (T2). Regarding the pressure-flow-curves there was no difference during OLV between the two groups indicating no major blocking effect of dopexamine on hypoxic pulmonary vasoconstriction. Conclusion: It is concluded that dopexamine can be used to improve haemodynamics and oxygen delivery during thoracic surgery without increasing venous admixture during one-lung ventilation.     

Effects of dopamine, dopexamine and dobutamine on renal excretory function during experimental sepsis in conscious rats

Background: Acute renal failure is a frequent complication in human sepsis. Various inotropic drugs are often used to improve central haemodynamics and renal function. The differential preservative role of the most commonly used inotropic drugs on renal function, in this condition, has previously not been extensively studied. The aim of this experimental animal study was therefore to compare the preserving effects of dopamine, dopexamine, dobutamine and saline on renal excretory function, after induction of sepsis in conscious rats. Method: The effects of dopamine (DA) (2.5 μg · kg^-1 · min^-1; n= 11), dopexamine (DX) (1 μg·kg^-1· min^-1; n=10), dobutamine (DB) (5 μg·kg^-1· min^-1; n=10) and saline (n=13) on the glom-erular filtration rate (GFR), urine flow (UF), sodium excretion (SE) and fractional urinary excretion of sodium (FUE_Na) were studied and compared in conscious rats subjected to a 1-h infusion of live E. coli bacteria (10⁹/h). Results: In the saline-treated control group, bacteria infusion decreased GFR, UF, SE and FUE_Na by 31%, 53%, 51% and 36% respectively, associated with a 16% decrease in mean arterial pressure (MAP), and a 10% increase in heart rate (HR). In the post-E. coli treatment period, the fall in MAP was less pronounced with DX compared to both DB and control, while there was no difference between DX and DA. The increase in HR was most pronounced with DB. GFR decreased to a lesser extent with DX compared to DA, DB and control. UF and SE were better maintained with DX compared to DB and control, while there was no difference in FUE_Na between the groups. Conclusion: We conclude that dopexamine, to a greater extent than dopamine and dobutamine, improves renal excretory function in experimental septic shock.     

Interleukin-10 and Interleukin-1 receptor antagonists increase during cardiac surgery

Background

It has been reported that inflammatory cytokines such as interleukin-8 and 6 (IL-8, IL-6) increase during cardiac surgery and cause postoperative cardiac dysfunction. Therefore, it is important to investigate changes of suppressive cytokines such as IL-10, interleukin-4 (IL-4) and interleukin-1 receptor antagonist (IL-1 ra) dunng cardiac surgery.

Method

Serum levels of cytokines and IL-1 ra were measured in 10 patients during cardiac surgery with cardiopulmonary bypass. Six blood samples were drawn after inducing anaesthesia. In each sample, serum IL-10, IL-4, IL-8, IL-6 and IL-1 ra were measured by enzyme linked immunosorbent assay.

Results

Serum IL-6 and IL-8 concentration (19.1 ±8.8 pg · ml^?1, and 13.4±5.2 pg · ml^?1, preoperatively) increased to 227.5± 191 pg · ml^?1 and 81.0±56 pg · ml^?1 at 60 min after declamping the aorta (P< 0.01, respectively). Serum IL-10 concentration increased at 60 min after dedamping the aorta compared with the preoperative value (from 1.0±0 pg · ml^?1 to 552.0± 158 pg · ml^?1 P< 0.001]). Similarly, serum IL-1 ra concentration increased from the preoperative value of 1331±896 pg · ml^?1 to 43353±12812 pg · ml^?1 at 60 min after dedamping the aorta (P< 0.00l). Positive correlations were obtained between IL-10 and IL-8. and between IL-10 and IL-6 (γ=0.7, γ=0.8, P< 0.001, respectively).

Conclusion

These findings demonstrate that pro-and anti-inflammatory cytokines increase to maintain their balance during cardiac surgery.     

Methylprednisolone inhibits increase of interleukin 8 and 6 during open heart surgery

It has been reported that interleukin 8 (IL-8) and interleukin 6 (IL-6) are two of the chemical mediators causing myocardial injury. It is not clear whether treatment with corticosteroids in vitro in these patients can prevent the production of interleukin 8 and 6. This prospective study was conducted to investigate whether methylprednisolone (MP) pretreatment (30 mg · kg^?1 before CPB and before declamping of aorta) influenced the production of IL-8 and 6 in the peripheral circulation in 27 patients undergoing elective coronary artery bypass surgery. The IL-8 and IL-6 concentrations were measured by ELISA kit. We also studied the effect of MP pretreatment on postoperative cardiac Junction. Serum concentration of IL-8 in non-MP-treated patients (37 ± 44 pg · ml^?1 preoperatively) increased to 169 ± 86 pg · ml^?1 60 min after declamping of the aorta (P < 0.001). The increase was greater than the increase from 22 ± 8.9 pg · ml^?1 to 52 ± 35 pg · ml^?1 in the MP-treated patients (P < 0.01). Serum IL-6 concentration in non-MP-treated patients increased from the preoperative value of 59 ± 30 pg · ml^?1 to 436 ± 143 pg · ml^?1 60 min after declamping of the aorta (P < 0.001). The increase was greater than the increase from 36 ± 15 pg · ml^?1 to 135 ± 55 pg · ml^?1 in the MP-treated patients (P < 0.01). Furthermore, postoperative cardiac index in MP-treated patients (3.6 ± 1.1 L · min^?1· m^?2) was higher than 2.3 ± 0.8 L · min^?1 · m^?2 of non MP-treated patients (P < 0.05). The levels of IL-8 max during surgery correlated negatively with postoperative cardiac index (γ = ?0.67). These results suggest that methylprednisolone suppresses production of IL-8 and 6.     

Comparison Between D901 Lilliput 1 and Kids D100 Neonatal Oxygenators: Toward Bypass Circuit Miniaturization

Progress in biomaterial technology and improvements in surgical and perfusion strategy ameliorated morbidity and mortality in pediatric cardiac surgery. In this study, we describe our clinical experience comparing performance of two neonatal oxygenators. From January 2002 to March 2011, 159 infants with less than 5 kg body weight underwent heart surgery. Ninety‐four patients received a D901 Lilliput 1 oxygenator with standard bypass circuit (group A), while 65 received a D100 Kids with miniaturized bypass circuit (group B). Miniaturization consisted in shortened arterial, venous, cardioplegia, and pump‐master lines. Priming composition consisted in Ringer's acetate solution with addition of albumin and blood, with target hematocrit of 24% or greater. In group B cardiopulmonary bypass (CPB) was vacuum‐assisted and started with an empty venous line. Modified ultrafiltration and Cell‐Saver blood infusion was routinely applied in both groups. Average ± standard deviation (SD) age at repair was 37 ± 38 days in group A and 59 ± 60 days in group B (P = 0.005). Average ± SD weight, height, and body surface area were 3.5 ± 0.7 kg, 52 ± 4 cm, and 0.22 ± 0.03 m², respectively, in group A, and 3.7 ± 1 kg, 53 ± 5 cm, and 0.23 ± 0.02 m², respectively, in group B (P = not significant [NS]). Male sex was predominant (55 vs. 58%, P = NS). Priming volume was 524 ± 67 mL (group A) and 337 ± 53 mL (group B) (P = 0.001). There were no statistical differences in hemoglobin at the start, during, and at the end of CPB, but group A required higher blood volume added to the prime (111 ± 33 vs. 93 ± 31 mL, P = 0.001). In group B, two surgical procedures were completed in total hemodilution. In group B, CPB time and aortic cross‐clamp time were shorter than in group A (106 ± 52 vs. 142 ± 78 min and 44 ± 31 vs. 64 ± 31 min, respectively, P = 0.001). There were 16 hospital deaths in group A and 4 in group B (P = 0.04). Durations of mechanical ventilation and intensive care unit stay were 5.3 ± 3.2 vs. 4.1 ± 3.2 days (P = 0.02) and 6.5 ± 4.9 vs. 5.1 ± 3 days (P = 0.03), respectively. There were significant differences in inotropic score (1083 ± 1175 vs. 682 ± 938, P = 0.04) and blood postoperative transfusion (153 ± 226 vs. 90 ± 61 mL, P = 0.04). Twenty‐seven patients in group A and 10 in group B presented with major adverse postoperative complications (P = 0.04). Use of neonatal oxygenators with low priming volume, associated with a miniaturized bypass circuit, seems to be a favorable strategy to decrease postoperative morbidity after cardiac surgery in neonates and infants.     

Postoperative junctional ectopic tachycardia

Purpose

To report the management of junctional ectopic tachycardia after cardiac surgery in an infant. Postoperatively, the patient suffered profound cardiac decompensation secondary to the accelerated rhythm and required extracorporeal membrane oxygenation (ECMO) for haemodynamic support.

Clinical features

A 14-day-old, 3.5 kg boy exhibited junctional ectopic tachycardia after cardiopulmonary bypass. Left atrial pressure was 25–28 mmHg. No impact on the tachycardia was seen after rapid overdrive atrial pacing or after 20 μg fentanyliv, 45 μg digitalis, 100 mg magnesium or procainamide (loading dose 15 mg, then 30 mg·kg^?1·min^?1). Active cooling decreased the nasopharyngeal temperature to 35.2°C, when the heart rate decreased below 180 bpm with a left atrial pressure of 8–10 mmHg. Dopamine (2 μg·kg^?1·min^?1) and dobutamine (5 μg·kg^?1·min^?1) were added to improve the cardiac output. Sodium nitroprusside (0.25 to I μg·kg^?1·min) maintained the systolic pressure <100 mmHg. On arrival in ICU, heart rate increased to 200 bpm. The patient received cardiac massage for severe hypotension 75 min after surgery. Emergency ECMO was instituted for circulatory support. Procainamide, digoxin, dopamine, dobutamine, sodium nitroprusside and hypothermia were continued. Sinus rhythm resumed on the first postoperative day, but procainamide and induced hypothermia at 34°C were maintained for 36 hr after normalization of the rhythm to prevent recurrence of the tachycardia. Total duration of ECMO was three and a half days. Recovery was uneventful.

Conclusion

The use of ECMO, as a first line of defence, is suitable for the emergency support of patients with JET because of the ease of support of circulation and precise control of hypothermia.     

Sodium nitroprusside after cardiac surgery: systemic and splanchnic blood flow and oxygen transport

Background: Vasoactive drugs may interfere with splanchnic blood flow and tissue oxygenation. Sodium nitroprusside (SNP) is widely used in the treatment of postoperative hypertension after cardiac surgery, but the effects of SNP and other vasodilators on splanchnic blood flow have not been well documented. Methods: The effects of SNP on systemic blood flow, oxygen transport and gastric intramucosal pH (pH_i) were studied in 12 patients with arterial hypertension after coronary artery bypass grafting. In 9 of these patients, the effect on regional (splanchnic and leg) blood flow and oxygen transport was also measured. Hemodynamic and regional blood flow responses were measured before and during SNP infusion (mean 2.8±1.7 μg/kg/min, range 0.6-6.3 μg/kg/min), when the goal of the vasodilator treatment, mean arterial pressure 70–80 mmHg, had been reached. Results: SNP increased splanchnic (0.65±0.22 vs. 0.87±0.37 L·min^-1·m^-2, P<0.01) and femoral blood flow (0.15±0.04 vs. 0.21±0.06 L·min^-1·m^-2, P<0.05) in parallel with cardiac index (2.6±0.6 vs. 3.3±0.7 L·min^-1·m^-2, P<0.01). Fractional regional blood flows did not change. Mean gastric intramucosal pH decreased slightly (7.40±0.07 vs. 7.37±0.06, P<0.05). Both systemic (420±85 vs. 495±90 mL·min^-1·m^-2, P<0.05) and femoral oxygen delivery (25±5 vs. 32±10 mL·min^-1·m^-2, P<0.05) increased, but neither systemic nor regional oxygen consumption changed. Conclusions: These results suggest that vasoregulation is well preserved during treatment of early postoperative hypertension with SNP, and that SNP has no adverse effects on splanchnic tissue oxygenation.     

Hemostatic consequences of a non-fresh or reconstituted whole blood small volume cardiopulmonary bypass prime in neonates and infants

Objectives: Despite aggressive measures to miniaturize the cardiopulmonary bypass (CPB) circuit in neonates and infants, the CPB prime volume is often at least as large as the patients’ blood volume. We conducted an observational study to characterize the hemostatic consequences of a CPB prime consisting of either non‐fresh or reconstituted whole blood. Methods: Hematocrit, fibrinogen, platelet count, plasminogen, anti‐thrombin III (AT‐III), and factors (F) II, V, VII, IX, and X of 30 neonates and infants undergoing cardiac surgery with CPB utilizing either a non‐fresh or reconstituted whole blood prime were prospectively evaluated at eight time points. Following protamine administration, microvascular bleeding was treated by protocol. Results: The hemostatic composition of the CPB prime was the same following the use of either non‐fresh or reconstituted whole blood. The CPB prime platelet count (mean ± sd ) was 5.87 ± 2.84 × 10³ μl^?1 when compared to a preoperative platelet count of 298 ± 142 × 10³ μl^?1 (P < 0.0001). Twenty patients received 17.3 ± 9.2 ml·kg^?1 (0.86 ± 0.46 units·kg^?1) of platelets with significant improvement in platelet count. Nine patients received 16.7 ± 13.4 ml·kg^?1 (0.84 ± 0.67 units·kg^?1) of cryoprecipitate with significant improvements in FVIII and fibrinogen. Conclusions: Non‐fresh or reconstituted whole blood as a component of a small volume CPB prime in neonates and infants induces clinically significant dilutional thrombocytopenia in conjunction with less significant reductions in fibrinogen, FII, FV, FVII, FVIII, FIX, FX, plasminogen, and AT‐III.     

Effect of a Miniaturized Cardiopulmonary Bypass System on the Inflammatory Response and Cardiac Function in Neonatal Piglets

The cognitive impairment and hemodynamic instability after neonatal cardiac surgery with cardiopulmonary bypass (CPB) might be exacerbated by hemodilution. Therefore, this study investigated the impact of different bloodless prime volumes on the hemodynamics and the inflammatory response by a miniaturized CPB system in neonatal piglets. The bypass circuit consisted of a Capiox RX05 (Capiox Baby RX, Terumo Corp., Tokyo, Japan) oxygenator and 3/16 internal diameter arterial and venous polyvinyl chloride tubing lines, with a minimum 75 mL prime volume. Twelve 1‐week‐old piglets were placed on a mild hypothermic CPB (32°C) at 120 mL/kg/min for 2 h. The animals were divided into two groups, based on the volume of the prime solution. The priming volume was 75 mL in Group I and 175 mL in Group II. No blood transfusions were performed, and no inotropic or vasoactive drugs were used. The interleukin‐6 (IL‐6) and thrombin‐antithrombin (TAT) complex levels, as well as right ventricular and pulmonary functions, were measured before and after CPB. Group I had low levels of IL‐6 and TAT immediately after CPB (4370 ± 2346 vs. 9058 ± 2307 pg/mL, P < 0.01 and 9.9 ± 7.7 vs. 25.1 ± 8.8 ng/mL, P < 0.01, respectively). Group I had significantly improved cardiopulmonary function, cardiac index (0.22 ± 0.03 vs. 0.11 ± 0.05 L/kg/min, P < 0.001), and pulmonary vascular resistance index (7366 ± 2860 vs. 28 620 ± 15 552 dynes/cm⁵/kg, P < 0.01) compared with Group II. The miniaturized bloodless prime circuit for neonatal CPB demonstrated that the influence of hemodilution can reduce the subsequent inflammatory response. In addition, a low prime volume could therefore be particularly effective for attenuating pulmonary vascular resistance and right ventricular dysfunction in neonates.     

A comparison of the Nexfin® and transcardiopulmonary thermodilution to estimate cardiac output during coronary artery surgery

The newly introduced Nexfin^® device allows analysis of the blood pressure trace produced by a non‐invasive finger cuff. We compared the cardiac output derived from the Nexfin and PiCCO, using transcardiopulmonary thermodilution, during cardiac surgery. Forty patients with preserved left ventricular function undergoing elective coronary artery bypass graft surgery were studied after induction of general anaesthesia and until discharge to the intensive care unit. There was a significant correlation between Nexfin and PiCCO before (r² = 0.81, p < 0.001) and after (r² = 0.56, p < 0.001) cardiopulmonary bypass. Bland–Altman analysis demonstrated the mean bias of Nexfin to be ?0.1 (95% limits of agreement ?0.6 to +0.5, percentage error 23%) and ?0.1 (?0.8 to +0.6, 26%) l.min^?1.m^?2, before and after cardiopulmonary bypass, respectively. After a passive leg‐raise was performed, there was also good correlation between the two methods, both before (r² = 0.72, p < 0.001) and after (r² = 0.76, p < 0.001) cardiopulmonary bypass. We conclude that the Nexfin is a reliable method of measuring cardiac output during and after cardiac surgery.     

Reduced-dose rocuronium for day-case tonsillectomy in children where volatile anaesthetics are not used: operating room time saving

Objectives: Mivacurium, rocuronium, and vecuronium are neuromuscular blocking agents (NMB) commonly used in pediatric day‐case anesthesia. Mivacurium is the most appropriate NMB for short surgical procedures where NMB drugs were required but is not available in all countries. Aim: We evaluated the operating room time minimization after reduced‐dose rocuronium (0.45 mg·kg^?1) during elective day‐case tonsillectomy in children. Methods/Materials: One hundred and five children (6–9 years, ASA I/II status) scheduled for day‐case tonsillectomy were included in prospective, double blind clinical study. Children were randomly divided in three equal groups. All children were premedicated (midazolam 0.25 mg·kg^?1 orally, EMLA). Anesthesia was induced (2.5 mg·kg^?1) and maintained (0.1 mg·kg^?1·min^?2) by propofol and alfentanil (0.0015 mg·kg^?1·min^?1) and supplemented by inhalation mixture of 50% of O2/Air. Neuromuscular block was achieved by vecuronium (0.1 mg·kg^?1) (V) or rocuronium in standard (0.6 mg·kg^?1) (R) or reduced dose (0.45 mg·kg^?1) (LD). Neuromuscular transmission was monitored by acceleromyography. Time analysis of NMB drugs action was performed. Results: Time difference from the end of tonsillectomy to T90 neuromuscular block recovery was significantly shorter in LD Group (7.3 ± 0.41 min), (V = 15.9 ± 1.06, R = 16.0 ± 1.7 min) (P = 0.0011). The onset time of neuromuscular block was prolonged in LD Group (LD=3.1 ± 0.4, R = 1.3 ± 0.4, V = 2.2 ± 0.2 min) (P = 0.0039) without changing the intubating conditions. The maximum operation room time saving per each tonsillectomy was 37% in LD Group (Group V 21%, Group R 17%) (P = 0.0001). Low incidence of postoperative nausea and vomiting (PONV) 3–6% (0.4577) and good visual analog scale (VAS) score (≤2) (0.5969) were found in all study groups 12 h after surgery. Conclusions: Reduced‐dose rocuronium in addition with propofol and alfentanil in children where volatile anesthetics are not used effectively saves the operating room time during short elective surgical procedures, avoids delays in patient recovery, allows high level of acceptable intubating conditions, and improves the optimal surgical work. Low incidences of PONV as VAS score may achieved successfully.     

Cardiac output increases the rate of carbon monoxide elimination in hyperpneic but not normally ventilated dogs

Purpose The very high solubility of carbon monoxide (CO) in blood suggests that its elimination depends predominantly on ventilation and not perfusion. Nevertheless, hyperventilation is not used for CO elimination because of the adverse effects of hypocapnia. With isocapnic hyperpnea (IH), ventilation can be increased considerably without hypocapnia. This raises the issue of whether CO elimination is limited by perfusion during IH. We studied the effect of increasing cardiac output on t_1/2, the half-time of decline of blood carboxyhemoglobin concentration ([COHb]), during normal ventilation (NV) and during IH. Methods After ethics approval was received, 13 pentobarbital-anesthetized ventilated dogs were exposed to CO to increase their [COHb]. They were then ventilated with NV or IH. At each level of ventilation, dogs were randomly assigned to treatment with dobutamine (to increase cardiac output) or to no dobutamine treatment. After the return of [COHb] to control levels, each dog was re-exposed to CO and treated with the same ventilatory mode, but the alternative inotropic treatment. Results Gas exchange, [COHb], and hemodynamic measures were recorded during the study. Cardiac index values in the IH group were 4.1 ± 0.5 and 8.2 ± 1.2 l·min⁻¹·m⁻² without and with dobutamine infusion, respectively. Dobutamine infusion was associated with a reduction in t_1/2 from 20.3 ± 3.6 to 16.9 ± 2.4 min (P = 0.005) in the IH group, but no change in the NV group. Conclusion These findings suggest that CO elimination during IH treatment is limited at least partly by pulmonary blood flow and may therefore be further augmented by increasing cardiac output. None of the authors have any source of support of the form of grants, gifts, equipment, or drugs.     

Amrinone,in combination with norepinephrine,is an effective first-line drug for difficult separation from cardiopulmonary bypass

A crucial element for weaning patients from cardiopulmonary bypass (CPB) rests on the selection of an appropriate therapeutic regimen. Amrinone, a phosphodiesterase III inhibitor, combines inotropic support with pulmonary and systemic vasodilatation, without increasing heart rate (HR) or myocardial oxygen consumption. These characteristics should be useful in the failing heart during weaning from CPB. Nineteen patients were included in this prospective, open-labelled, phase IV study when systolic blood pressure (SBP) <80 mmHg, and diastolic pulmonary artery pressure (DPAP) > 15 mmHg or central venous pressure (CVP) > 75 mmHg, during progressive separation from CPB. At that moment, CPB flow was increased to alleviate heart failure and amrinone administered as a bolus (0.75 mg · kg^?1) followed by an infusion (10 μg · kg^?1 · min^?1). Weaning from CPB was then resumed and haemodynamic variables (SBP, DPAP, CVP and HR) were compared with those measured at CPB flow when failure had first occurred. Failure to wean from CPB occurred at 57 ± 25% of full pump flow. After the amrinone bolus, DPAP and CVP decreased by 20% and 21% respectively. Subsequently, 16 patients required the infusion of norepinephrine (4-8 fig-min^?1) to maintain a SBP > 80 mmHg. Heart rate remained unchanged after the bolus of amrinone, after separation from CPB, and no arrhythmias were noted. Successful weaning from CPB was possible 12 ± 8 min after the amrinone bolus. Weaning resulted in a cardiac index similar to that measured pre-bypass. Amrinone is rapidly effective during weaning from CPB and, in combination with norepinephrine, provides the necessary inotropic support during this unstable period.