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Biomedical subjects

A Michalopoulos

Publications and source records attributed to A Michalopoulos.

At least 19 recordsLinked to original sources
PubMed1999

Myoelectric assessment of large bowel viability: an experiment in dogs.

OBJECTIVE: To design a device for myoelectric assessment of intestinal ischaemia and compare it with every day surgical experience and Doppler signals recorded on the bowel wall. DESIGN: Experimental study. SETTING: Thessaloniki university hospital, Greece. MATERIAL: 12 adult mongrel dogs. INTERVENTIONS: On the first day the large intestine was devascularised for a length of 20 cm, 5 cm away from the ileocaecal valve, and the threshold of the electric stimulus (mA) required to produce a contraction of the normal large bowel was recorded. On the second day, measurements were made on the ischaemic segment of the large bowel at 0.5 cm intervals. Bowel resection and anastomoses were done at the stimulus level of 40 mA. RESULTS: The mean (SD) stimulus threshold of the normal large intestine was 12.2 mA. The necrotic intestine demanded current stimulus of 100 mA or failed to contract. On the eighth postoperative day the animals were killed to assess anastomotic healing. Of the 12 anastomoses made at the 40 mA stimulus point, only one ruptured. The 40 mA limit of the stimulus level seems to be of value in assessments of bowel viability in vivo. CONCLUSION: The use of a personal computer as a read out device makes myoelectric analysis easier and more reliable in the assessment of intestinal viability. This method may have a clinical application.

Anastomosis, Surgical↗
PubMed1999

Determinants of hospital mortality after coronary artery bypass grafting.

OBJECTIVES: To examine causes of death and to find predictors of hospital mortality after elective coronary artery bypass graft (CABG) surgery. DESIGN: Case-control study. SETTING: Tertiary teaching hospital. METHODS: We prospectively collected various preoperative, operative, and immediate postoperative variables in a cohort of patients undergoing elective CABG surgery. RESULTS: Of the 2,014 consecutive patients (mean [+/- SD] age of 61.3+/-6.7 years old) undergoing elective CABG over a 2-year period, 27 patients (1.3%) died during their hospitalization. The main causes of death (either isolated or in combination) were cardiogenic shock (n = 13), brain death or stroke (n = 7), septic shock (n = 4), ARDS (n = 2), and pulmonary embolism (n = 1). A univariate statistical analysis revealed factors that significantly correlate with outcome: patient age, preoperative left ventricular ejection fraction, bypass time, aortic cross-clamp time, number of blood units transfused, number of inotropic agents administered in the operating room during the first postoperative day (POD), history of arterial hypertension, intra-aortic balloon pump usage, and perioperative development of shock. A logistic regression analysis showed that the combination of the number of inotropes and the number of blood units administered in the operating room during POD 1 was the most important determinant of outcome, with an overall positive predictive value of 91.7%. CONCLUSIONS: We conclude that the analysis of simple variables enhances our ability to accurately predict hospital mortality in patients undergoing elective CABG surgery. The number of inotropic agents and blood transfusions administered during the immediate postoperative period is the most important independent predictor of hospital mortality.

Adult↗
PubMed1998

Change in anaesthesia practice and postoperative sedation shortens ICU and hospital length of stay following coronary artery bypass surgery.

We randomized prospectively 144 patients, undergoing elective coronary artery bypass surgery, to either early or to routine extubation [mechanical ventilatory support for 4-7 h (Group A), or 8-14 h (Group B)]. Anaesthesia was modified for both groups. The groups were well matched in terms of sex, age, NYHA class, preoperative left ventricular ejection fraction, bypass time and aortic cross-clamp time, number of grafts used, and blood units transfused. All patients had normal preoperative respiratory, renal, hepatic and cerebral functions. Mechanical ventilatory support (mean +/- SD) was 6.3 +/- 0.7 h for Group A and 11.6 +/- 1.3 h for Group B. Mean ICU stay was 17 +/- 1.3 h for Group A and 22 +/- 1.2 h for Group B, while the mean hospital stay was 7.3 +/- 0.8 days and 8.4 +/- 0.9, respectively. There were no statistically significant differences in the frequency of all postoperative complications among the two groups. There were no reintubation, readmission to the ICU or death in either group. We concluded that change in anaesthesia practice and early postoperative sedation in patients undergoing elective coronary artery bypass graft (CABG) surgery resulted in earlier tracheal extubation, shorter ICU and hospital length of stay without organ dysfunction or postoperative complications. Early extubation was only possible due to the modification of anaesthesia and ICU sedation regime.

Aged↗
PubMed1998

Effects of positive end-expiratory pressure (PEEP) in cardiac surgery patients.

The role of positive end-expiratory pressure (PEEP) in the postoperative course of cardiac surgery patients remains questionable. In this prospective study, we examined the effect of different levels of PEEP on arterial oxygenation, SvO2 and PvO2 values, and on haemodynamic indices, during the early postoperative period in cardiac surgery patients. Upon transfer to the ICU, 67 adult patients with normal preoperative respiratory status were randomly assigned to receive zero PEEP (Group A), 5 cmH2O (Group B), or 10 cmH2O PEEP (Group C) during mechanical ventilatory support. PaO2/FIO2 ratio, mixed venous PvO2 and SvO2, and cardiac index, were measured 30 min, 4 h and 8 h after application of mechanical ventilation in the ICU, just prior to extubation, half an hour after extubation, and 4 h post-extubation. We found no statistically significant differences (P = n.s.) in arterial oxygenation expressed by PaO2/FIO2 ratio, SvO2 and PvO2 values, and in cardiac index among the three groups at any study interval. We conclude that low levels of PEEP have no advantage over zero PEEP in improving gas exchange in the early postoperative course of patients following open heart surgery.

Analysis of Variance↗
PubMed1998

Severe sepsis in cardiac surgical patients.

OBJECTIVE: To elucidate the incidence, determinants, and consequences of severe sepsis after cardiac surgery. DESIGN: Prospective study. SETTING: Cardiac surgical unit, Greece. SUBJECTS: 2615 adult patients having cardiac operations. MAIN OUTCOME MEASURES: Microbiological evidence of sepsis, mortality, and duration of stay in the intensive care unit (ICU) and hospital. RESULTS: Severe sepsis developed in 41/2615 patients (2%), all during their stay in the ICU: there were 30 men and 11 women, mean (SD) age 65 (10) years. It was most common after combined coronary artery bypass grafting and valve-related operations (7/95, 7%), followed by miscellaneous cardiac operations (7/147, 5%), valve replacement (8/359, 2%), and coronary artery bypass grafting (19/2014, 1%). When the 41 patients who developed severe sepsis were compared with those who did not (n = 2574) by univariate analysis, there were significant differences in age (p = 0.004); type of operation (p < 0.0001); duration of operation (p < 0.001); bleeding that necessitating either reoperation or significantly more blood transfused (p < 0.0001); and the incidence of low cardiac output syndrome (p = 0.0001). Of the 41 patients with severe sepsis, 19 (46%) had serious operative complications, 40 (98%) had severe complications in the ICU, and 16 (39%) required reintubation for hypoxaemia. Among the 41 there were 54 bacteraemic episodes of which 37 (69%) were caused by gram positive cocci, 6 (11%) by gram negative bacteria, and 11 (20%) by Candida albicans. Staphylococcus epidermidis was the most common pathogen isolated (n = 26, 48%). Sepsis associated with bacterial infection usually developed during the first two weeks, and that caused by fungal infection was most common after the twentieth postoperative day. Patients with severe sepsis required longer mechanical ventilation (31 (21) days compared with 0.9 (0.1) days); longer stay in the ICU (40 (25) days) compared with 2 (1) days); longer stay in hospital (48 (27) days compared with 10 (2) days); and significantly more of them died (13 (32%) compared with 41 (2%), p < 0.0001 in each case). CONCLUSIONS: We concluded that severe sepsis mainly developed in cardiac surgery patients with serious operative and postoperative complications and was associated with a longer stay in both ICU and hospital, and a higher mortality.

Adult↗
PubMed1997

Systemic candidiasis in cardiac surgery patients.

OBJECTIVE: To examine the frequency, predisposing factors and consequences of systemic candidiasis in cardiac surgery patients. We also examined fluconazole efficacy in the treatment of disseminated fungal disease. METHODS: A total of 2615 adult patients of mean +/- S.D. age 60.8 +/- 8.7 years who underwent open heart surgery between July 1993 and April 1995, were enrolled in the initial protocol. Patients were divided in two groups according to length of stay in the intensive care unit (ICU). The cut-off was a length of stay of 9 days. RESULTS: In the group of patients with prolonged stay (n = 54), 11 patients (20.3%) developed systemic candidiasis, usually after the twentieth postoperative day. Predisposing factors were patient age, history of diabetes mellitus, presence of central venous catheters, prolonged mechanical ventilatory support, prolonged ICU stay, and administration of antibiotics and of total parenteral nutrition for a prolonged period. The patients who developed systemic candidiasis had a median ICU and hospital stay of 58 and 60 days respectively. The mortality rate was 27.2%. Patients receiving fluconazole, improved and eventually negative cultures were obtained. CONCLUSIONS: We concluded that a significant percentage of patients who remained in the cardiothoracic ICU for more than 9 days developed systemic candidiasis. Systemic candidiasis resulted in a significant prolongation of ICU and hospital length of stay, thus increasing extensively total hospitalization costs. Fluconazole seems to be an effective and well-tolerated agent in the treatment of severe life-threatening systemic candidiasis, and a very good alternative to amphotericin B, in cardiac surgery patients.

Adolescent↗
PubMed1997

Antibiotic prophylaxis in cardiac surgery.

BACKGROUND: A prospective, randomised study was conducted among 1009 cardiac surgery patients in order to compare the prophylactic efficacy of a second generation cephalosporin (cefuroxime) given as single shot, versus a broad spectrum double regimen (amoxycillin-netilmicin). METHODS: Cefuroxime received 501 patients (Group A), while a 4-day combination of amoxycillin-netilimicin 508 patients (Group B). RESULTS: There were found no statistically significant differences either in infection rate or the kind of infection between the two groups. Single shot cefuroxime prophylaxis was just as effective, as a 4-day combination of amoxycillin and netilmicin. Total infection rate was 5.6% (n=28) in Group A and 5.7% (n=29) in Group B. Respiratory tract infection was the most frequently registered in both groups; 2.6% in Group A and 2.9% in Group B. Sternal wound and catheter-related infection rates were 0.6% and 1% in both groups, respectively. There were no side effects due to the given antibiotics. CONCLUSIONS: A single shot of cefuroxime prophylaxis is equally effective and safe as a 4-day regimen with amoxycillin and netilmicin.

Aged↗
PubMed1996

Comparison of gastric air tonometry with standard saline tonometry.

OBJECTIVE: To compare partial pressure of carbon dioxide (PCO2) measurements obtained by sampling gastric intraluminal air with those obtained by standard saline tonometry. DESIGN: Prospective, unblinded study. SETTING: Intensive care unit in a tertiary cardiac surgical center. PATIENTS: 20 patients undergoing cardiac surgery. INTERVENTIONS: Gastric tonometric catheters were inserted, gastric fluid was aspirated, and 100 cc of air was injected into the stomach. MEASUREMENTS: After an equilibration period of 30 min, samples of gastric air and saline were anaerobically aspirated and analyzed on a standard blood gas machine. The reproducibility of PCO2 measurements in a given patient was assessed by analyzing consecutive samples of gastric air and calculating the coefficient of variation (CV). RESULTS: PCO2 values measured in samples of gastric air (PCO2 air) were highly correlated with those derived by saline tonometry (PCO2ss)(r2 = 0.95, p = 0.0001); PCO2 air was significantly greater than PCO2ss (50 +/- 17 vs 48 +/- 17 mmHg, p = 0.0001). Intramucosal pH (pHi) calculated from PCO2 air was significantly lower than that calculated from PCO2ss (7.26 +/- 0.23 vs 7.28 +/- 0.24, p = 0.0001). Analysis of intermethod differences showed significant bias for both PCO2 (2.4 +/- 7.6 mmHg, mean +/- 2SD, bias +/- precision) and pHi ( -0.023 +/- 0.074, mean +/- 2SD, bias +/- precision). The within-subject variability of replicate PCO2 measurements in gastric air was low (CV = 2.6 +/- 0.8). CONCLUSION: We conclude that intraluminal PCO2 can be accurately determined in postoperative cardiac surgery patients by instilling air into the stomach and analyzing samples of gastric air on a standard blood gas machine, In comparison with saline tonometry, air tonometry consistently yields lower pHi values.

Aged↗
PubMed1996

Determinants of duration of ICU stay after coronary artery bypass graft surgery.

Prediction of duration of a patient's stay in the ICU after cardiac surgery is difficult. In 652 consecutive adult patients undergoing elective coronary artery bypass graft (CABG) surgery, we analysed prospectively preoperative and immediate postoperative variables thought to influence duration of stay in the ICU. With univariate analysis, we found that age, preoperative left ventricular ejection fraction, bypass time, aortic cross-clamp time, blood transfusions and the number of inotropic agents administered in the immediate postoperative period (for at least 6 h) were significant correlates of duration of stay in the ICU. However, logistic regression analysis showed that the number of inotropes was the most important determinant of stay in the ICU, with an overall prediction accuracy of 94.8%. The main cause of prolonged stay in the ICU (more than 2 days) was low cardiac output syndrome. We conclude that analysis of perioperative variables enhanced our ability to accurately predict duration of stay in the ICU in cardiac surgery patients. The number of inotropic agents administered during the first 6 h after operation was the most important determinant of duration of stay in the ICU.

Adult↗
PubMed1996

Subtotal cholecystectomy.

Subtotal cholecystectomy has been carried out in 34 patients from 1972 to 1992. In the same period 1620 total cholecystectomies were performed. The indications were severe inflammation and/or severe fibrosis in 31 patients, and Mirizzi syndrome type 1 in 3 patients. The morbidity was insignificant, but one patient died, due to severe sepsis. In follow up studies ranging from 6 months to 9 years, there was one patient with retained stones in the common bile duct. No other post cholecystectomy sequelae were noticed in the remaining 32 patients. Subtotal cholecystectomy is a safe, feasible and definitive operation in patients for whom the standard operation could be dangerous. This operation is less burdensome to the patient, and is accompanied by fewer complications than ordinary cholecystostomy.

Adult↗
PubMed1986

[Association of a rare form of testicular ectopia, a persistent Müllerian duct syndrome and a supernumerary ectopic epididymis].

We report the first case of persistence of the Müllerian duct associated with transverse testicular ectopia and a supernumerary ectopic epididymis in the same hemiscrotum. The patient is a thirty-year-old man with azoospermia. Uterine and Fallopian tube structures were clearly recognizable within the Müllerian remnants. The ectopic supernumerary epididymis was detected at the lower pole of one of the two testicles and had to be removed surgically.

Adult↗
PubMed1979

The fate of patients with intraventricular conduction disturbances complicating acute myocardial infarction.

The partial incidence and the early and late mortality were studied in 104 patients with acute myocardial infarction complicated by intraventricular conduction defects. Right bundle branch block and left anterior hemiblock had a greater incidence than the other conduction anomalies, while the hospital mortality was greater for the complete right bundle branch block combined with left anterior or posterior hemiblock, followed in order by complete left bundle branch block. Late morality was higher in cases with complete right bundle branch block combined with left posterior hemiblock and also in cases with focal block or left bundle branch block indicating a poor prognosis for these patients. For the rest sub-groups of patients late mortality was relatively low indicating the possibility of long survival after passing the acute phase. However, longer periods of observation are desirable for further estimation of their ultimate prognosis.

Aged↗
PubMed1978

Transient abnormal Q waves during acute myocardial infarction.

A 65 years old woman with an acute myocardial infarction, as it was judged by serial enzyme changes, developed transitory Q waves in V2-V4 and II, III and AVF during the attack of chest pain. These Q waves were not present 12 hours later. It is suggested that these changes represent a focal block in the septal fibers of the left bundle system. This defect could explain the transient right precordial Q waves seen in myocardial infarction or ischemia, as well as the fixed Q waves of many patients without septal infarction at autopsy.

Acute Disease↗
PubMedDate not supplied

Antibiotic prophylaxis in gastroduodenal surgery.

BACKGROUND/AIMS: In a retrospective process quality control trial, proper use of antimicrobial prophylaxis in gastroduodenal operations according to the standard guidelines was studied. PATIENTS AND METHODS: A total of 132 consecutive adult patients (pts), who underwent gastroduodenal surgery in a University Hospital, were enrolled to this study protocol. There were 88 males and 44 females of with mean (+/-SD) age of 58.7 (+/-9.1) years old. The patients were divided into 4 groups based on surgical antibiotic prophylaxis policy. Group A consisted of surgical pts receiving appropriate antibiotic prophylaxis (a 2nd generation cephalosporin) when there was indication. Group B consisted of pts without indication who did not receive prophylaxis, Group C pts who, although antibiotic prophylaxis was indicated, were not given prophylaxis, and Group D pts without indication who received prophylaxis. RESULTS: Of 132 pts examined, appropriate antibiotic prophylaxis was received by 28 pts (21%) (Group A). In 62 pts (47%), antibiotic prophylaxis was not indicated and not administered (Group B). On the contrary, in 42 pts (32%), although antibiotic prophylaxis was indicated, it was not given (Group C). No patient received prophylaxis without indication. The following infections were found: wound infection (n = 10), pneumonia (n = 6), severe sepsis (n = 2), urinary tract infection (n = 2), and fever of unknown origin (n = 2). Where correct antibiotic prophylaxis policy was followed (Groups A and B), 6 post-operative infections occurred (6.7%), with a mean (+/-SD) hospital length of stay 14.4 (+/-3.2) days. In contrast, in the group with incorrect antibiotic prophylaxis policy (group D), 16 infectious complications occurred (38%) (p = 0.001), with a mean (+/-SD) hospital length of stay 22.5 (+/-4.4) days (p = 0.001). Total hospitalization costs were much higher in this group compared with Groups A and B (p = 0.01). Mortality rate was 9.5% in Group D, while no deaths occurred in the other groups (p = 0.01). CONCLUSION: Antimicrobial prophylaxis policy is an important issue, targeting lower morbidity or avoidable costs.

Aged↗
PubMedDate not supplied

Hepatic dysfunction following cardiac surgery: determinants and consequences.

BACKGROUND/AIMS: We prospectively studied the determinants, characteristics, and consequences of hepatic dysfunction in the early postoperative period following cardiac surgery. METHODOLOGY: We examined 3041 adult patients, mean age 60.6 (+/- 8.9), with normal pre-operative liver function who consecutively underwent open heart surgery in a newly established Cardiac Surgery Center. Patients were divided into two groups; Group A included all patients who developed hepatic dysfunction, defined as the presence of jaundice associated with an elevated serum bilirubin above 3 mg/dl, in the early postoperative period. The control group included cardiac surgical patients who did not develop such dysfunction. RESULTS: Hepatic dysfunction developed in 96 patients (3.2%). The affected patients consisted of 63 males and 33 females, mean age 60.8 (+/- 9.4). Determinants of hepatic dysfunction based on univariate analysis were sex, NYHA class, type of surgery, operative times, low cardiac output syndrome necessitating administration of inotropic agents and/or IABP usage, cardiac arrest, presence of hematomas, and number of blood transfusions. Patients with hepatic dysfunction required prolonged mechanical ventilation, stayed longer in the ICU (and in the hospital) and experienced a much higher mortality rate (11.4%) compared to the control group (p = 0.001). CONCLUSION: Although the pathogenesis of hepatic dysfunction seems to be multifactorial, liver cell damage due to decreased perioperative hepatic flow and increased bilirubin load seem to be of critical importance. Early postoperative hepatic dysfunction resulted in increased morbidity and mortality.

Adolescent↗