[Effect of locally applied lidocaine on expression of the oculocardiac reflex]

INTRODUCTION

The oculocardiac reflex causes severe bradycardic arrhythmias and is a frequent complication during surgical manipulation at the medial rectus muscle. The purpose of this study was to evaluate the influence of lidocaine administered topically on the muscle on the incidence of the oculocardiac reflex.

PATIENTS AND METHODS

After obtaining informed consent, 140 patients with strabism or retinal surgery were included in this study. All patients received standard premedication and anesthesia and were randomly assigned to two groups. Patients (n = 70) randomly assigned to the first group received 1 mg/kg lidocaine applied topically to the muscle after opening the conjunctiva. Individuals in the placebo group received the same volume of saline (0.9%). Surgical stimulation occurred 5 min after administration of the drug. The study parameters (blood pressure/heart rate) were recorded before and after stimulation of the oculocardiac reflex caused by routine surgical preparation.

RESULTS

Topical administration of lidocaine reduced the incidence of the oculocardiac reflex (86.1% vs 37.1%), and the frequency of severe bradycardiac arrhythmias was also significantly reduced (40 vs. 2.9%). Cardiac arrest for longer than 10 s did not occur in the lidocaine group. In the control group this phenomenon was observed in 14.8%.

[Mechanical myocardial support systems 1997: an overview of inta-aortic balloon counterpulsation to implantable left ventricular support systems]

The development of cardiopulmonary bypass (CPB) to support the systemic circulation during cardiac surgical procedures became a clinical reality in 1953. Although the use of CPB for the treatment of post-infarction cardiogenic shock met with little success, intra-aortic balloon counterpulsation was used successfully in 1968 to reduce ischaemic injury in a patient with cardiogenic shock. Today, a broad spectrum of circulatory assist devices for short- and long-term application is available. Three major indication groups for the use of support devices are established. In low-cardiac-output syndrome after cardiac surgical procedures, short-term devices are utilised to enable myocardial recovery. In transplantation candidates suffering from drug-resistant pump failure, the implantation of long-term devices as a bridge to heart transplantation is indicated, and in NYHA class IV patients with contraindications to heart transplantation, the implantation of long-term devices as an alternative to transplantation is under discussion. In the literature, post-cardiotomy support survival is less than 30% on average. About 70% of mechanically bridged patients have survived to undergo heart transplantation and were transplanted with over 90% survival. Major problems during mechanical support are infection, bleeding, and thromboembolism. In view of patients' natural course without support, these clinical results are favourable.

Effects of dopexamine on creatinine clearance, systemic inflammation, and splanchnic oxygenation in patients undergoing coronary artery bypass grafting

Impairment of splanchnic and peripheral tissue perfusion during cardiopulmonary bypass (CPB) may be responsible for endotoxin-mediated systemic inflammation and acute phase responses. We examined the effects of dopexamine on hemodynamic parameters, creatinine clearance, systemic and splanchnic oxygenation, gastric mucosal pH (pHi), and mixed and hepatic venous plasma levels of endotoxin, interleukin-6 (IL-6), serum amyloid A (SAA), and C-reactive protein (CRP) in 44 patients scheduled for coronary artery bypass grafting. Patients were randomized to receive continuous infusions of 0.5, 1.0, or 2 micrograms.kg-1.min-1 dopexamine (n = 10 per group) or placebo (n = 14) prior to surgery, intraoperatively, and postoperatively. Dopexamine infusion increased systemic oxygen delivery (P < or = 0.01). Hepatic venous oxygen saturation did not change, and pHi decreased during and after CPB in all patients (P < or = 0.01). Postoperative increases in IL-6 were smallest in patients who received 2.0 micrograms.kg-1.min-1 dopexamine (P < or = 0.02). SAA and CRP increases during the postoperative period were less pronounced with dopexamine throughout the study. Creatinine clearance was elevated in all dopexamine groups (P < or = 0.025). This elevation was higher with lower dopexamine doses (P < or = 0.025). We conclude that dopexamine improves creatinine clearance and reduces systemic inflammation without affecting splanchnic oxygenation.

The effects of thoracic epidural anesthesia on functional recovery from myocardial stunning in propofol-anesthetized dogs

The purpose of this investigation was to examine the effects of thoracic epidural anesthesia (TEA) on myocardial stunning during propofol anesthesia. Six dogs were chronically instrumented for measurement of left atrial, aortic, and left ventricular pressure, maximal rate of increase of left ventricular pressure, and myocardial wall-thickening fraction (WTF). Myocardial blood flow was determined with colored microspheres. Experiments were performed on separate days with 1) 10 min of left anterior descending artery (LAD) ischemia during propofol anesthesia without TEA, and 2) 10 min of LAD ischemia during propofol anesthesia with TEA. WTF was measured as baseline (BL) prior to propofol anesthesia and at predetermined time points until complete recovery from stunning. Propofol anesthesia caused a significant decrease of WTF in the LAD-perfused myocardium (LAD-WTF) compared to BL in awake animals. LAD ischemia led to a further significant decrease of LAD-WTF. There were no significant differences in LAD-WTF between the two experimental conditions at any of the time points measured. TEA did not change subendocardial blood flow in nonischemic myocardium. During ischemia neither the subendocardial/subepicardial nor the occluded/normal zone blood flow ratio were affected by TEA. After myocardial ischemia during propofol anesthesia TEA does not affect functional recovery of stunned myocardium in dogs.

Influence of enoximone on systemic and splanchnic oxygen utilization and endotoxin release following cardiopulmonary bypass

OBJECTIVE

We investigated whether the administration of enoximone during and after cardiopulmonary bypass (CPB) improves splanchnic oxygen utilization and thereby gut mucosal integrity in humans by its vasodilating and inotropic properties.

SETTING

Surgical intensive care unit (ICU) in a university hospital.

DESIGN/PATIENTS

21 patients (ASA III classification) scheduled for elective coronary artery bypass grafting were enrolled in the study. After induction of general anesthesia, patients were randomly assigned to received a bolus of 0.2 mg/kg enoximone, followed by 5 microg/kg per min (enoximone group), or followed by an equal volume of saline (NaCl group) during and 24 h after the surgical procedure. The following parameters were evaluated at different time intervals: systemic and pulmonary hemodynamics, blood gas analysis of arterial, mixed venous, and liver venous blood, venous and liver venous lactate level, venous and liver venous endotoxin level and intramucosal partial pressure of carbon dioxide for calculation of intramucosal pH (pHi).

RESULTS

Enoximone raised cardiac output and oxygen delivery to higher levels than those observed in the NaCl group. In both groups, gastric pHi fell continuously during the study period. The values were significantly decreased 12 h following admission to the ICU. Endotoxin was not detectable at baseline. Both groups showed increased endotoxin levels, with the highest values during the first 6 h postoperatively. The hepatic venous endotoxin level was almost doubled in the NaCl group in comparison to the enoximone group. Endotoxin levels differed in the two groups 6 and 12 h after admission to the ICU.

CONCLUSIONS

Improvement of oxygen delivery by enoximone did not prevent gastric mucosal acidosis following CPB. However, since the increase in endotoxin levels in liver venous blood was diminished by using enoximone, the drug seems to have a beneficial effect on tissue damage and barrier function of the gut.

Biological bridging after repair of an anomalous origin of a left coronary artery

We report on an unusual case of surgical repair for anomalous origin of the coronary artery from the pulmonary artery, in a young patient who underwent tunnel repair with concomitant heterotopic heart transplantation to support severely impaired left ventricular function. Four years later, the graft was removed after confirmation of ventricular arrest and excellent recovery of the patient's own heart.

Thoracic epidural anesthesia improves functional recovery from myocardial stunning in conscious dogs

The effects of thoracic epidural anesthesia (TEA) on the contractile performance of ischemic and postischemic myocardium have not been well investigated. The purpose of this investigation was to examine the effects of TEA on severity and duration of myocardial stunning in an experimental model for sublethal acute myocardial ischemia. Seven dogs were chronically instrumented for measurement of heart rate (HR), left atrial (LAP), aortic and left ventricular pressure (LVP), LV dP/dtmax' and myocardial wall-thickening fraction (WTF). An occluder around the left anterior descending artery (LAD) allowed induction of reversible LAD ischemia. TEA was performed with lidocaine 4 mg/kg through a chronically implanted epidural catheter at the second thoracic level. Regional myocardial blood flow was determined with colored microspheres. Two experiments were performed in a cross-over design on separate days: Experiment 1, induction of 10 min of LAD ischemia without TEA; and Experiment 2, induction of 10 min of LAD ischemia with TEA. WTF was measured at baseline (BL) and predetermined time points until complete recovery from ischemic dysfunction occurred. LAD ischemia caused a significant decrease of LAD-WTF with (-28% +/- 5.1% versus BL) and without TEA (-15.5% +/- 5.3% versus BL). After 3 h of reperfusion, WTF as percent of BL values was significantly higher with TEA (P < 0.001). BL values of WTF were reached after 24 h with TEA and after more than 48 h without TEA (P < 0.05). There were no significant differences for mean arterial pressure (MAP), heart rate (HR), LVP, LAP, and LVdP/dtmax between the groups during ischemia and reperfusion. In nonischemic myocardium TEA caused an increase of subendocardial blood flow. During ischemia neither the subendocardial/subepicardial nor the occluded/ normal zone blood flow was affected by TEA. TEA attenuates myocardial stunning in conscious dogs. This finding is consistent with data regarding a reduction of infarct size due to TEA.

Low-flow and minimal-flow anaesthesia using the laryngeal mask airway

This study was designed to investigate whether the advantages of low- and minimal-flow anaesthesia can be combined with the laryngeal mask airway (LMA). Seventy female patients undergoing routine gynaecological surgery were investigated. After induction of anaesthesia and after positioning a laryngeal mask airway nos 3 and 4, patients were ventilated for 20 min with a fresh gas flow of 6 L min-1. Thereafter, the flow was reduced to 1 L min-1 in 50 patients and to 0.5 L min-1 in 20 patients. Once in the proper position, the LMA allowed flow reduction in all patients, indicating that no gas leakage occurred. It is concluded, that the application of low-flow and even minimal-flow anaesthesia is an alternative to high-flow anaesthesia. It can result in high annual savings and minimization of pollution. However, its use should be restricted to those anaesthesiologists who are experienced with the laryngeal mask airway and minimal-flow anaesthesia.

A new method for continuous intramucosal PCO2 measurement in the gastrointestinal tract

Gastric tonometry has been introduced for the early detection of impaired splanchnic perfusion by determination of the intramucosal PCO2. However, due to methodological problems, i.e., instability of CO2 in water, to assess the exact intramucosal PCO2 with the nasogastric tonometer is unreliable. The present in vitro and in vivo study examines a new fiberoptic PCO2 sensor for the continuous determination of the intramucosal PCO2 and compares these data with that of conventional tonometry. In an in vitro experiment the fiberoptic PCO2 sensor was used to determine the PCO2 of water and humidified air with predefined CO2 values. In both media, predefined CO2 values (35, 42, 49 mm Hg) could be assessed exactly after 9 min of equilibration with a maximum deviation less than 3.5%. In contrast, the values obtained by conventional tonometry showed larger differences. In in vivo experiments on six pigs PCO2 differences were induced by ventilatory changes to validate the fiberoptic PCO2 sensor. Under anesthesia a laparotomy was performed, the ileum punctured, and the fiberoptic PCO2 sensor introduced into the ileal lumen. Arterial PCO2 (PaCO2), mesenteric venous PCO2 (PmvCO2), and intramucosal PCO2, (PiCO2) were determined during normoventilation, hypoventilation, and hyperventilation. During hypoventilation the PiCO2 increased from 53.8 +/- 2.0 mm Hg (PaCO2 = 39.8 +/- 1.4 mm Hg, PmvCO2 = 48.7 +/- 2.7 mm Hg) to 66.5 +/- 4.9 mm Hg (PaCO2 = 52.7 +/- 3.1 mm Hg, PmvCO2 = 62.4 +/- 5.7 mm Hg). With hyperventilation the PiCO2 decreased to 46.8 +/- 2.5 mm Hg (PaCO2 = 29.8 +/- 1.8 mm Hg, PmvCO2 = 41.8 +/- 2.7 mm Hg). The coefficient of correlation (r2) between PiCO2 and PaCO2 was 0.82, and between PiCO2 and PmvCO2 0.94. The fiberoptic PCO2 sensor can determine PiCO2 in a precise and reliable manner, and can continuously record fast intraluminar changes of CO2 in the ileum that were caused by ventilatory changes. The fiberoptic PCO2 sensor is the only method that reliably monitors PiCO2 in the gastrointestinal tract. By the direct measurement of PCO2 the methodological problems associated with the conventional nasogastric tonometry are abolished.

Impact of left ventricular dysfunction on cytokines, hemodynamics, and outcome in bypass grafting

BACKGROUND

Although patients with reduced left ventricular ejection fraction undergoing cardiac operation experience a higher rate of perioperative complications, the contribution of proinflammatory cytokines released during extracorporeal circulation is not well defined.

METHODS

We compared arterial and mixed venous levels of interleukin-6, tumor necrosis factor-alpha, soluble interleukin-2 receptor, and interleukin-2 at 10 points in time (24 hours before until 48 hours after extracorporeal circulation) in 21 patients with an ejection fraction of less than 0.45 (study group) to 15 patients with an ejection fraction of more than 0.55 (control group) undergoing elective coronary artery bypass grafting. The study and control group differed with regard to left ventricular ejection fraction (0.37 +/- 0.05 versus 0.66 +/- 0.11, p < 0.05) and reperfusion time (35 +/- 42 minutes versus 18 +/- 4 minutes, p = 0.07), but not age, sex, vessel involvement, number of grafts performed, cross-clamp time, extracorporeal circulation time, core temperature, and duration of ventilation.

RESULTS

Six patients in the study group required mechanical support and 1 died. There were no complications in the control group. In the study group, there were higher preoperative interleukin-2 and tumor necrosis factor-alpha levels and a higher maximum cytokine response to extracorporeal circulation for interleukin-2, soluble interleukin-2 receptor, interleukin-6, and tumor necrosis factor-alpha (all p < 0.05). Interleukin-6 correlated with duration of extracorporeal circulation, dose of norepinephrine and epinephrine support, pulmonary capillary wedge pressure, mean pulmonary arterial pressure, right atrial pressure, heart rate, cardiac index, and inversely with systemic vascular resistance. Interleukin-6 was highest in patients with complications. Arterial and venous cytokine levels correlated closely.

CONCLUSIONS

Preoperative left ventricular dysfunction is associated with a higher degree of proinflammatory cytokine release during elective coronary artery bypass grafting. This response is associated with impaired hemodynamics and a higher incidence of perioperative complications.

The effect of laryngeal mask cuff pressure on postoperative sore throat incidence

STUDY OBJECTIVE

To study the effect of laryngeal mask airway (LMA) cuff pressure on the incidence of postoperative sore throat.

DESIGN

Prospective, randomized, observational study.

SETTING

Operating room of a university hospital.

PATIENTS

200 consecutive adult patients requiring anesthesia for gynecologic procedures.

INTERVENTIONS

Anesthesia was induced with thiopental 3-5 mg/kg, fentanyl 2 micrograms/kg, vecuronium bromide 0.05mg/kg, and enflurane 0.8% to 2% and maintained with nitrous oxide and oxygen (65%/35%) and enflurane.

MEASUREMENTS AND MAIN RESULTS

In Group 1, cuff pressure measurement was continuously performed until the end of the operation. In Group 2, 5 minutes after induction of anesthesia and 2 minutes after insertion of the LMA, cuff pressure was also continuously observed and reduced to the minimal pressure required for airtightness. In the recovery room, after the operation, patients were questioned for postoperative sore throat 4, 8, and 24 hours after the operation following a scoring protocol (score 0 = no complaints, score 1 = minimal sore throat, score 2 = moderate sore throat, score 3 = severe sore throat: "never a LMA again". Continuous monitoring of cuff pressure revealed a steady increase of pressure (during the first 60 minutes increases of 43 cm H2O) in Group 1. In Group 2, after release of air, cuff pressures were significantly lower through the entire operation when compared with Group 1. In Group 1, 8 patients claimed to have a sore throat (Score 1, n = 4; Score 2, n = 3; Score 3, n = 1). In Group 2, no patient complained of sore throat.

CONCLUSIONS

A significant increase in cuff pressure is seen during the first 60 minutes. Three minutes after insertion of the laryngeal mask, cuff pressure can significantly be reduced without any major gas leakage. Postoperative sore throat can be reduced when cuff pressure is continuously monitored and kept on low-pressure values.

Beating heart implantation of a wearable NOVACOR left-ventricular assist device

Implantable left-ventricular assist devices (LVAD) are successfully used as a bridge to transplant if the patient's condition is worsening and no donor organ is available. They allow recovery of compromised organ function. However, postoperative bleeding, thrombemboelism, and right-heart failure may jeopardize the important improvement of organ function and may even lead to death. We introduce our strategy for implantation of the Novacor LVAD system, which aims at minimal bleeding and maintained right-heart function. The Novacor LVAD was implanted with the heart beating during extracorporeal circulation in 8 patients, 3 of whom had previous cardiac surgery. Postoperatively, no patient developed right heart failure or had to undergo redo thoracotomy.

Cardiopulmonary bypass in patients with heparin-induced thrombocytopenia using Org 10172

BACKGROUND

In patients with heparin-induced thrombocytopenia undergoing cardiac operations, anticoagulation with heparin should be avoided. The low-molecular-weight glycosaminoglycan Orgaran has been used as an alternative, but the overall experience is limited.

METHODS

Two patients with heparin-induced thrombocytopenia underwent cardiopulmonary bypass using Orgaran for anticoagulation. A 30-year-old woman suffered from emboli to her brain through a secondary atrial septal defect, a 14-year-old boy from ischemia of his left leg due to recurrent embolism originating from the mitral valve. In both cases, cardiopulmonary bypass was performed in a routine manner, except for using low-dose Orgaran instead of heparin. Anticoagulation was monitored during cardiopulmonary bypass by measuring Orgaran plasma levels and activated clotting time.

RESULTS

No thromboembolic or bleeding complications occurred during and after atrial septal defect repair and mitral valve replacement, respectively. In the former case, thrombotic material from the inferior vena cava was removed during hypothermic circulatory arrest within the same procedure. Activated clotting time did not correlate with plasma levels of Orgaran.

CONCLUSIONS

Orgaran might be a useful alternative for anticoagulation during extracorporeal circulation. Adequate dosages and measurement of plasma levels are recommended for its use in cardiopulmonary bypass.

Cardiac output is not affected during intraoperative testing of the automatic implantable cardioverter defibrillator

INTRODUCTION

Perioperative mortality of patients undergoing implantation of automatic implantable cardioverter defibrillators (ICDs) has been reduced dramatically following the availability of transvenous-subcutaneous defibrillation leads. However, patients with severely reduced left ventricular function show a substantial rate of nonsudden cardiac mortality within the first year. Whether repeated intraoperative inductions of ventricular tachycardia/fibrillation (VT/VF) during implantation lead to hemodynamic deterioration and thus might contribute to development of end-stage heart failure in these patients is unknown. The purpose of the present study was to determine cardiac output and hemodynamic performance during transvenous-subcutaneous ICD implantation in patients with severe left ventricular dysfunction.

METHODS AND RESULTS

In 11 patients with a left ventricular ejection fraction (EF) < or = 0.35, cardiac output was measured automatically with a combined continuous cardiac output/mixed venous oxygen saturation pulmonary artery catheter system. ICD implantation was performed during standardized general anesthesia. In the 11 patients (EF = 27 +/- 2% [mean +/- SEM]) a total of 95 episodes of VT/VF followed by defibrillation were induced (episodes per patient = 9 +/- 1; range 6 to 11). Cardiac index was 2.2 +/- 0.2 L.min-1.m-2 after induction of anesthesia (before start of surgery), and 1.9 +/- 0.1 L.min-1.m-2 immediately before first induction of VT/VF. After the last episode of VT/VF, cardiac index was 2.1 +/- 0.2 L.min-1.m-2. Cardiac index measured 1, 2, and 3 minutes after induction of VT/VF was not significantly different when compared to the preinduction value during any episode of VT/VF induction. Similarly, stroke volume index was 39 +/- 5 mL.m-2 immediately before first induction of VT/VF and 36 +/- 3 mL.m-2 after the last episode of VT/VF (NS). At the end of surgery, hemodynamic parameters did not exhibit any significant difference when compared to the data obtained before start of ICD implantation and testing.

CONCLUSION

Extensive defibrillation tests during transvenous-subcutaneous ICD implantation in patients with severe left ventricular dysfunction are not associated with acute deterioration of cardiac performance.

Attenuation of the oculocardiac reflex after topically applied lignocaine during surgery for strabismus in children

The effect of topical lignocaine applied to the eye muscles, on the incidence of the oculocardiac reflex during squint surgery of the medial rectus was investigated in 56 healthy children aged between 3-14 years. Three groups were studied. One (n = 16): stimulation of the reflex without lignocaine; 2 (n = 10): stimulation of the reflex after topical administration of 1 mg kg-1 lignocaine 2% to the medial part of the eye after induction of anaesthesia; 3 (n = 30): stimulation of the oculocardiac reflex without, and after a 5 min interval under the influence of lignocaine. Topical administered lignocaine significantly attenuated the OCR (105 vs. 68 bpm group II vs. group 1:82 vs. 63 bpm in group III). Severe bradycardiac rhythm disturbances, in particular cardiac stand-still, were not observed after lignocaine had been applied. Systemic side effects of lignocaine were not seen.

Recurrent bilateral carotid body tumors. A case report on a 'typical' course of a rare disease

A 34-year-old female patient suffered from bilateral swelling of the neck for more than 10 years until carotid body tumors were diagnosed. In a local hospital, the right-sided tumor was dissected from the carotid arteries, the contralateral tumor was considered unresectable. in our institution, the left cervical mass was completely removed, and 4 years later, recurrency on the right side was similarly operated upon. Due to tumorous infiltration both recurrent nerves, both internal jugular veins, and both the left internal and external carotid artery had to be sacrificed. Carotid boyd tumors are often inadequately treated, despite the simplicity of establishing diagnosis with angiographic and scintigraphic techniques, because they are not included in different diagnosis during assessment.

[Nausea and vomiting after gynecologic laparoscopies]

OBJECTIVE

To investigate the occurrence of postoperative nausea and vomiting (PONV) in relation to the menstrual cycle in patients anaesthetised with isoflurane and propofol.

METHODS

150 patients were randomly allocated to two groups (n = 75). All patients received antiemetic treatment with 20 micrograms/kg droperidol i.v. before induction of anaesthesia. In the isoflurane group, patients were anaesthetised with thiopental, fentanyl, vecuronium, and isoflurane; in the propofol group, with propofol, fentanyl, and vecuronium. Patients were ventilated with nitrous oxide/oxygen in both groups.

RESULTS

Under isoflurane-based anaesthesia PONV occurred in 22 (29%) patients, under propofol-based anaesthesia in 4 (5%) patients (p < 0.05). 41 study participants underwent laparoscopy during the first 8 days of the menstrual cycle. 12 (29%) of these patients developed PONV (p < 0.05 vs second and third phase of the menstrual cycle). 10 of these 12 study participants were in the isoflurane group. Postoperative shivering occurred in 38 (51%) patients anaesthetised with isoflurane and in 12 (16%) patients of the propofol group (p < 0.05).

CONCLUSIONS

The incidence of PONV is significantly higher when patients undergo laparoscopy during the first 8 days of the menstrual cycle. When compared to isoflurane, propofol results in a significantly lower incidence of PONV and postoperative shivering and a lower occurrence of postoperative pain.

Arterial and venous cytokine response to cardiopulmonary bypass for low risk CABG and relation to hemodynamics

During and after cardiopulmonary bypass (CPB), cytokines may affect cardiac performance and the immune response and are therefore of diagnostic and therapeutic interest. We have used EIA/EASIA kits to measure arterial and venous levels of interleukin-1-beta (IL-1-beta), IL-2, IL-2 receptor (IL-2-R), IL-6, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma in 12 men and 3 women (mean age 59.4 +/- 8.5 years, mean left ventricular ejection fraction 66 +/- 11%, average of 2.5 +/- 0.64 vessels affected by disease) undergoing elective coronary artery bypass grafting (CABG). On average each patient received 3 +/- 0.85 bypass grafts and required a postoperative maximum dopamine-dose of 3.8 micrograms/kg per min. Mean CPB and operation times were 60 +/- 21 min, and 132 +/- 16 min, respectively. During CPB, the venous levels of IL-2 temporarily decreased from 234 to 0 (p < 0.05) pg/ml and arterial and venous levels of IL-2-R temporarily decreased from 28 to 16, and 36 to 18 pM (p < 0.05), respectively. After termination of CPB, there was an increase in the arterial and venous levels of IL-6 from below 3 to 253 and 277 pg/ml (p < 0.05) and TNF-alpha from 1.1 to 5.7 and 0.7 to 4.0 pg/ml, respectively (p < 0.05). Tumor necrosis factor-alpha-increases peaked 30 min, and IL-6 increases peaked 4 h after termination of CPB. Twenty-four hours after the end of CPB, IL-6 showed a tendency to return to baseline, but still remained significantly elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of superoxide dismutase on reperfusion injury in donor hearts preserved with Bretschneider-HTK cardioplegic solution

The ability of superoxide dismutase to prevent reperfusion injury after long-term cold storage of donor hearts was evaluated in canine hearts. Whole blood reperfusion was performed using a 'support animal'. Twelve dog hearts were arrested by a single dose of Bretschneider cardioplegic solution and stored cold (0.5 degrees C) for 24 h. Thereafter they were reperfused for 60 min without (n = 6) or with (n = 6) superoxide dismutase treatment. Myocardial tissue biopsies were taken for determination of high-energy phosphates before explantation, after the preservation period and during reperfusion. Early reperfusion in both groups resulted in an initial recovery of high-energy phosphates and was followed by a decrease during the subsequent reperfusion phase. The latter was associated with the appearance of left ventricular contracture, and cessation of heart beat. Electron microscopic examination of the myocardial tissues after reperfusion revealed a severe reperfusion injury in both groups. It is concluded, that in donor hearts preserved with Bretschneider solution, reperfusion injury cannot be prevented by administration via the perfusate of superoxide dismutase.

Left ventricular assistance using a catheter-mounted coaxial flow pump (Hemopump) in a canine model of regional myocardial ischaemia

The global and regional effects of left ventricular circulatory assistance were examined in dogs during acute myocardial infarction using a new coaxial flow device (Hemopump). In 12 dogs the left anterior descending coronary artery was occluded for 4 h and subsequently reperfused for 12 h. In six dogs, left ventricular assistance was started 90 min after coronary artery occlusion and maintained for several hours; six control animals received no circulatory support. Survival rate in the animals receiving mechanical support was 100% vs 0% in the control group. The Hemopump reduced left ventricular stroke work up to 80% and maintained blood flows to the brain, kidneys, liver and intestine throughout the experiment. Infarct size, expressed as a percentage of the left ventricle, however, was not modified (12% in supported animals vs 13% in control dogs). Side effects of the coaxial flow pump were thrombocytopaenia, occurring in all six dogs, and haemolysis, which was demonstrated in one animal. It was concluded that the Hemopump provides effective global and regional circulatory support in a canine model of severe cardiogenic shock. However, the value of left ventricular support to modify infarct size could not be demonstrated in this experimental model.

Effect of nucleoside transport inhibition on adenosine and hypoxanthine accumulation in the ischemic human myocardium

The effect of nucleoside transport inhibition on the adenylate catabolism was studied in the human myocardium under normothermic ischemic conditions. Ten hearts from cardiac transplant recipients and two hearts from cardiac homograft donors were used in this study. The hearts were excised under hypothermic conditions (25 degrees C body temperature), the coronary arteries flushed with 500 ml ice-cold Ringer solution (n = 6; group I) or with ice-cold Ringer solution containing 1 mg/l of the nucleoside transport inhibitor R75231 (n = 6; group II). After transportation at 0 degree C from the operation room, the hearts were quickly rewarmed to 37 degrees C. Serial transmural biopsy specimens were taken during normothermic ischemia for determination of purine catabolites. The level of ATP before normothermic ischemia was 17.5 +/- 1.0 mumol/g dry weight in the control group (group I) and 19.3 +/- 0.4 mumol/g dry weight in the drug group. ATP, expressed as percentage of total purine content, was similar in both groups before rewarming (79.5 +/- 4.3% in group I and 79.5 +/- 2.9% in group II). There was no significant difference in the rate of ATP breakdown in both groups throughout the experiment (ATP was 3.0 +/- 1.4% of total purines in group I and 1.4 +/- 0.2% in group II at 120 min of normothermic ischemia). Adenine nucleotide content changed also similarly in both groups. Adenosine accumulation was, however, significantly higher in group II than in group I (peak values: 4.6 +/- 1.0% of total purines in group I vs 14.0 +/- 1.7% in group II; p < 0.01). The ratio between adenosine and inosine was significantly higher in group II throughout normothermic ischemia (p < 0.01). In spite of a larger accumulation of adenosine in group II, the increase in inosine was similar in both groups. We conclude that nucleoside transport inhibition significantly delays the breakdown of adenosine and the formation of hypoxanthine in the ischemic human myocardium.