Do on- and off-pump coronary bypass surgery differently affect perioperative peripheral tissue metabolism?

BACKGROUND

Microdialysis allows the in-vivo assessment of interstitial fluids. We studied the metabolic status of peripheral tissues (skeletal muscle) in patients undergoing coronary artery bypass surgery on- (CABG) or off-pump (OPCAB).

METHODS

Twenty patients candidates to elective coronary bypass surgery were randomly assigned to undergo CABG or OPCAB. A microdialysis catheter was inserted in the left deltoid muscle before surgery and left in place for 24 hours, and metabolic markers of peripheral tissue perfusion (glucose, lactate, pyruvate, glycerol and lactate/pyruvate (L/P) ratio) were assessed before, at the end, and 24 hours after surgery.

RESULTS

Preoperative clinical features were similar in both groups. Interstitial levels of glucose and lactate increased over time, being in both groups significantly higher than baseline 24 hours after surgery, whereas glycerol levels did not change over time and between groups. In addition, there was an increase over time of pyruvate levels which were significantly higher in CABG after surgery, whereas L/P ratio was significantly higher in OPCAB 24 hours after surgery.

CONCLUSION

Metabolic changes after coronary bypass surgery occur with some differences related to CPB use. Overall, these changes suggest that, after coronary surgery, a certain degree of hypermetabolic state ensues, lasting up to 24 hours after surgery; the postoperative increase in pyruvate levels in CABG patients, together with the changes in L/P ratio occurring only in OPCAB patients implies an higher risk of tissue hypoperfusion/ischemia for patients submitted to OPCAB, although this does not lead to permanent cellular damage, as the markers of this complication (e.g., glycerol) do not change over time.

Fenoldopam to prevent renal replacement therapy after cardiac surgery. Design of the FENO-HSR study

INTRODUCTION

Acute kidney injury requiring renal replacement therapy is a serious complication following cardiac surgery associated with poor clinical outcomes. Until now no drug showed nephroprotective effects. Fenoldopam is a dopamine-1 receptor agonist which seems to be effective in improving postoperative renal function. The aim of this paper is to describe the design of the FENO-HSR study, planned to assess the effect of a continuous infusion of fenoldopam in reducing the need for renal replacement therapy in patients with acute kidney injury after cardiac surgery.

METHODS

We're performing a double blind, placebo-controlled multicentre randomized trial in over 20 Italian hospitals. Patients who develop acute renal failure defined as R of RIFLE score following cardiac surgery are randomized to receive a 96-hours continuous infusion of either fenoldopam (0.025-0.3 µg/kg/min) or placebo.

RESULTS

The primary endpoint will be the rate of renal replacement therapy. Secondary endpoints will be: mortality, time on mechanical ventilation, length of intensive care unit and hospital stay, peak serum creatinine and the rate of acute renal failure (following the RIFLE score).

CONCLUSIONS

This trial is planned to assess if fenoldopam could improve relevant outcomes in patients undergoing cardiac surgery who develop acute renal dysfunction. Results of this double-blind randomized trial could provide important insights to improve the management strategy of patients at high risk for postoperative acute kidney injury.

Cytological and histological diagnosis of lung cancer in Sardinia and Italy in the 1990s

BACKGROUND

Up to 30-50% of all lung cancer cases remain without cyto-histological characterisation. The aim of our study was to evaluate retrospectively the proportion of histological and/or cytological diagnosis in patients with lung cancer in Sardinia.

METHODS

Data was gathered by consulting the hospital registers and case notes of individual patients released from hospital with a diagnosis of Lung Cancer at all medical centres throughout Sardinia. In gathering patients' data, we focused our attention on cytological and histological procedures through which allowed the lung cancer was diagnosed. Cancer Registries data was utilised to compare our data with national and Sassari province data.

RESULTS

From 1991 to 1996 there was a total of 3146 lung cancer patients registered in Sardinia. 1902 patients (60.5%) had a histological diagnosis, 142 patients (4.5%) a cytological diagnosis while in 1102 patients (35%) the diagnosis was performed without any pathological validation.

CONCLUSIONS

Our study has shown that lung cancer diagnosis is supported by pathological verification in 65% of cases while in remaining 35% of patients the diagnosis is based only on clinical and radiological reports. In Italy data from Cancer Registries report the percentage of cytohistological diagnosis to be 70% with the percentage of cytological diagnosis being higher than in Sardinia.

Sudden death in epilepsy: An experimental animal model

INTRODUCTION

The physiopathogenetic mechanisms possibly involved in sudden unexplained epileptic death (SUDEP), were investigated in the hemispherectomized rat.

METHODS

For this purpose, paroxysmal activity, vagal nerve firing, systemic blood pressure (BP), pulmonary artery pressure, and ECG were simultaneously recorded in an experimental animal model of epilepsy. Recordings were performed in basal conditions and during paroxysmal activity induced by topical application of penicillin-G at hypothalamic and mesencephalic level. During the experiment were also performed hemogas analysis and at end, samples of lung tissue were processed for histology.

RESULTS

Activation of hypothalamic (HEF) and mesencephalic (MEF) epileptic foci induced a significant increase of spontaneous vagal nerve firing that was strictly correlated to ECG impairments and hypotension. When paroxysmal activity extinguished, vagal nerve activity and cardiovascular parameters returned to basal conditions. However, in 25% of the animals, co-activation of HEF and MEF always triggered a vagal hypertone which was temporally correlated to cardiac arrhythmias, but also to hyperkalemia, acidosis, pulmonary hypertension and to animal death. Histological control in lungs of deceased animals showed an alveolar and perivessel oedema with an oedematous infiltration in the alveolar and bronchial spaces and mucous secretion. During ictal activity, comparison between survived and deceased animals showed significant differences in the incidence of ECG impairment of pulmonary artery pressures, pO2, and pCO2 pressures, and [K+], [HCO3-], and [pH], concentrations.

DISCUSSION

A possible explanation of the above observations is discussed in relationship to SUDEP physiopathogenesis.

Epidemiology of lung cancer in Sardinia, Italy, from 1980 to 1996

SETTING

Bronchial carcinoma is the most common cause of death among all malignant tumours. Despite a progressive increase, many Italian regions--ours included--do not have a Regional Cancer Registry.

OBJECTIVE

To assess lung cancer incidence and mortality rates in Sardinia during the period 1980-1996.

METHODS

Data were gathered by consulting hospital registers and the case notes of individual patients released from hospital with a diagnosis of bronchial carcinoma at all Sardinian medical centres between 1980 and 1996.

RESULTS

A total of 7734 patients with lung cancer were registered in Sardinia between 1980 and 1996. Data showed a steady increase in lung cancer incidence rates over the years (from 22.3/100000 in 1980 to 34.5 in 1996). The same increase was evident in mortality rates (from 25.7/100000 in 1980 to 42.9 in 1996). The increase in mortality rates was higher in women (+146%) than in men (+59.5%).

CONCLUSIONS

Results show a slow but steady increase in lung cancer incidence and mortality rates in Sardinia. The high number of smokers among lung cancer patients seems to indicate that anti-smoking campaigns need to be more effective in Sardinia.

Original insight into continuous cardiac output monitoring: "TruCCOMS". Correlation with other methods

AIM

Of all technical devices used for continuous or intermittent monitoring of cardiac output, in our clinical practice during the last year, we tested a new system, the true continuoas cardiac output monitoring system (TruCCOMS), for the continuous real time measurement of cardiac output. The purpose of this study was to compare the accuracy, reliability and promptness of TruCCOMS with other systems and methods of cardiac output (CO) measurement such as pulsion continuous cardiac output (PiCCO) and end diastolic Area (EDA) determination by trans-esophageal-echocar-diography (TEE), keeping as gold standard for CO measurement the thermodilution method by Swan-Ganz.

METHODS

Sixteen male patients, aged 50 to 60 years, with ejection fraction (FE) >50%, EUROSCORE=1, who underwent CABG surgery with circulation extra corporeal (CEC), were analysed with all methods mentioned above. The measurements were obtained at different phases: pre-CEC; post-CEC; and Intensive Care Unit (ICU). In the ICU setting, 5 patients classified as under-filled with a pulmonary capillary wedge pressure (PCWP) =/<8 mmHg were filled until a PCWP gs;13 mmHg in order to evaluate the promptness of the various systems to detect the new condition.

RESULTS

The statistical analysis of data obtained in our survey, clearly demonstrates that TruCCOMS is at least equivalent to average thermo-dilution cardiac output (AvTDCO), with the advantage of being continuous, real time and, furthermore, with no need for physician intervention/interference.

CONCLUSION

In our experience the TruCCOMS seems to be an ideal method for continuous cardiac output (CCO) monitoring compared with the other bedside systems challenged.

Three cases of cardiac hydatidosis: diagnosis, surgical treatment, and complications

Three cases of cardiac hydatid disease from among the many cases of hydatidosis (>300) in various organs observed by the authors are reported. The sites of the cysts and the complications that arose are described. The first case developed hydatid pulmonary embolism caused by rupture into the right ventricular cavity, the second suffered peripheral hydatid embolism caused by rupture into the left ventricular cavity, and the third, whose diagnosis was fortuitous, had no complications. The first patient died shortly after admission. The other two underwent radical pericystectomy and partial pericystectomy with cardiopulmonary bypass. The best result was obtained in the third case where rupture had not occurred. The second patient recovered but developed hemiparesis. The various diagnostic tools available are discussed, as well as some technical aspects of pericystectomy, which has a high mortality rate. The importance of early diagnosis and treatment of this rare localization of Echinococcus granulosus is emphasized, and echocardiography is recommended even for nonspecific cardiac symptoms in areas where the parasite is endemic.

[The propofol-fentanyl-pancuronium combination in aorto-coronary bypass. Experience and personal caseload]

The authors report the use of a total intravenous anaesthesia in CABG. An association of propofol-fentanyl-pancuronium with a bolus at induction, then with continuous perfusion was used. Hemodynamic and oxymetric data obtained from the right heart and radial artery samples show good hemodynamic stability during surgery. It is underlined that, in order to reduce possible hemodynamic changes it is very important to use, during the surgical procedure, the lowest drug concentration.

[Temperature monitoring and sites of measurement of body temperature]

The authors report an investigation of 331 consecutive patients submitted to major surgery to evaluate the reliability of temperature monitoring in different body sites in relation to central temperature. After having considered the minimal temperature changes and the difficulties due to the different techniques used, it is concluded that the measurement at the middle 3rd of the oesophagus is the most reasonable measurements site.

[Circulation effects of noradrenaline in hyperdynamic septic shock]

The authors report on a group of 8 patients in septic shock, treated with NA in association with dopamine and/or dobutamine, according to a personal therapeutic protocol. The use of NA in septic shock with low SVR showed an improvement in hemodynamic condition and a higher survival rate in the treated patients. During the study many clinical, laboratory and microbiologic data were also recorded.

[Reducing bleeding during extracorporeal circulation interventions by high doses of aprotinin]

The great risk of severe infectious diseases transmission through blood transfusion, has increased during the last years the effort to reduce the bank blood and its derivates use. Many techniques have proposed to achieve this purpose during and post cardiopulmonary bypass: normovolemic hemodilution, perioperative blood autotransfusion, postoperative return of extra corporeal circuit and chest drains blood and the particular use of some drugs. In the last few years several reports have been presented in the literature concerning the reduction of intra and postoperative bleeding in cardiac surgery by high dose Aprotinin administration. A randomized study with the use of this pharmacologic agent is presented: a group of patients was treated with Aprotinin (shared in two subgroups receiving respectively a different dose of the drug) and a control group. The results were highly encouraging both because of the reduction of peri and postoperative bleeding and because of the bank blood use important reduction.

[Peroperative blood autotransfusion in heart surgery]

A drastic reduction in homologous blood or plasma transfusion becomes necessary to prevent the risks of severe infections disease transmission. The authors studied the possibility of homologous blood save in cardiac surgery by peroperative autotransfusion. This procedure, although it diminished the average blood bank requirements, above all for an unexplained decrease in postoperative bleeding, did not obtain the good results that other authors had with the technique of 2 or 3 preoperative withdrawal, storage and postoperative reinfusion. In future our trend is to associate preoperative and intraoperative withdrawals to take advantage of both techniques.

A case of hyperglycemic hyperosmolar non-ketotic coma during anesthesia: a possible cause of failed re-awakening

The case of a non diabetic 6-year-old boy affected by Down's syndrome, who developed hyperosmolar hyperglycemic non-ketotic coma following the infusion of hypertonic dextrose solution during general anesthesia for a surgical procedure for cryptorchidism is reported. Following surgery, the patient remained deeply comatose and generalized seizures occurred. Hyperosmolarity due to hyperglycemia and acidosis were reduced by administration of insulin at low rate, hypotonic saline and sodium-bicarbonate solutions. The patient's clinical conditions promptly improved following normalization of blood glucose levels. An oral glucose tolerance test performed three months later was normal. The authors emphasize the potential risk of hyperosmolar hyperglycemic non-ketotic coma also in non diabetic patients treated with hypertonic dextrose solutions, during surgery events.

[Botallo's duct with pulmonary hypertension in the adult]

A patent ductus arteriosus in adults is a rare eventuality. After correct diagnosis, an accurate evaluation of pulmonary vascular resistances is necessary with, in case of normality, a straightforward indication to surgery, because the evolution of the disease cannot be predicted. In case of pulmonary hypertension irreversible pulmonary vascular damage must be excluded. Haemodynamic data such as pressures, flows and resistance ratios are not reliable. According to the majority of Authors the value of pulmonary resistances seems to be more accurate, and when more then 8 u/m2 an histological specimen must be obtained. In our experience a comparative study between the Health and Edwards method and the Yamaki et al., one shows, confirmed by postoperative follow-up, a greater reliability of the second one.

Analysis of central cardioarrhythmogenic triggers in experimental epilepsy

The cardioarrhythmogenic potential of epileptic foci induced at mesencephalic and rhombencephalic levels was analyzed in hemispherectomized rats. Topical application of penicillin-G onto the mesencephalic quadrigeminal lamina or onto the fourth ventricle induced paroxysmal activity at the mesencephalic or bulbar neurone level. At the mesencephalic levels, the paroxysmal activity was characterized by a significant increase in the spontaneous frequency of the neurones, with the appearance of multiunit activity and rhythmical outbursts. The simultaneous recording of myocardial electrical activity and blood pressure showed that the paroxysmal activity triggered short-latency sinus bradyarrhythmias with wandering of the sinus pacemaker, the appearance of biphasic or negative P waves, some premature ventricular contractions and non-significant reduction of systolic and diastolic pressures. When the paroxysmal activity stopped, the cardiac rhythm and blood pressure returned to basal values. At the bulbar level, the paroxysmal activity appeared with longer latency and usually the rhythmical outbursts were not observed. Following bulbar paroxysmal activity only short-lasting episodes of sinus bradyarrhythmias appeared. Midcollicular transection eliminated paroxysmal activity at the bulbar level, and blood pressure and cardiac rhythm resumed basal values. After transection, an additional application of convulsant drug (penicillin-G or pentylenetetrazole) onto the fourth ventricle did not induce the reappearance of paroxysmal activity and the consequent cardiovascular alterations. The results showed the existence of a cardioarrhythmogenic trigger localized at the mesencephalic level which spreads paroxysmal activity upwards. A hypothesis to explain the appearance of fetal haemodynamic modifications and life-threatening arrhythmias has been proposed.

Neurogenic myocardial arrhythmias in experimental focal epilepsy

The potential for cardiac arrhythmia was studied in an experimental focal epilepsy induced in hemispherectomized rats by topical application of buffered penicillin G onto the thalamus. The epileptic burst triggered cardiac and hemodynamic responses, as simultaneously monitored by arterial pressure, and hypothalamic and heart activity. During interictal epileptic activity, the single burst triggered a short-latency cardiac arrhythmia, characterized by sinus bradyarrhythmia and junctional rhythm, and lengthening of intervals between sphygmic waves with significant reduction of diastolic pressure. When the epileptic burst stopped, the cardiac activity resumed normal rhythm, and diastolic pressure returned to basal value. During ictal epileptic activity, the sinus and junctional bradyarrhythmic episodes lasted longer, and supraventricular extrasystoles, sinus arrest, and bigeminal ventricular extrasystoles were observed. Both systolic and diastolic pressures decreased from 120/85 to 100/65 mm Hg. The end of the ictal episode always marked resumption of normal cardiac rhythm and systemic pressure. Considering the absence of metabolic complications (blood-gas analytic parameters and acid-base balance being controlled) and the short latency of the cardiac and hemodynamic responses, it is suggested that during paroxysmal hypothalamic activity the observed cardiac arrhythmias and the hemodynamic modifications were neurogenic in origin. A role for cardiovascular alterations in sudden unexplained epileptic death is postulated.

Omental transposition or transplantation to the brain and superficial temporal artery--middle cerebral artery anastomosis in preventing experimental cerebral ischaemia

Transposition of lengthened omentum to the brain surface, transplantation of an omental graft, or superficial temporal artery--middle cerebral artery anastomosis were performed in dogs prior to transcranial occlusion of the ipsilateral middle cerebral artery at its origin, including the bifurcation of the internal carotid artery. Both omentum and by-pass were able to reduce the changes in cerebral blood flow, somatosensory evoked responses, cerebral water and electrolyte content, consequent to the ischaemic insult. In the experimental conditions adopted in this study, the effect of omental transposition in maintaining high levels of flow throughout the entire occluded hemisphere was more marked compared to that resulting from the other methods, while the onset of ischaemic cerebral oedema was affected approximately at the same degree by all procedures. The results point to the role of the transposed omentum in providing an effective collateral circulation to the ischaemic brain.