Biomedical subjects

Serdar Gunaydin

Publications and source records attributed to Serdar Gunaydin.

9 recordsLinked to original sources

PubMed2006

Influence of hematocrit and pump prime on cerebral oxygen saturation in on-pump coronary revascularization.

BACKGROUND: The couplings between cerebral oxygenation (rSO2), on-pump hematocrit and circuit prime are explored in this study. METHODS: Thirty-eight consecutive patients undergoing coronary revascularization with cardiopulmonary bypass (CPB) were matched on preoperative hematocrit < 40% and > 40% (n = 16). Similarly, six blood prime patients were matched with six crystalloid prime patients. Hematocrit and rSO2 levels were then compared on CPB. RESULTS: The preoperative hematocrit > 40% group retained higher levels on pump run (p < 0.01) and significantly higher rSO2 prior to CPB (64.8 +/- 9.6 versus 73.2 +/- 7.3), and on and off CPB (61.1 +/- 8.8 versus 67.4 +/- 6.4). Blood priming increased absolute rSO2 (2.3 +/- 6.3 versus -10.9 +/- 5.9) and % rSO2 (4.7 +/- 11.8 versus -14.2 +/- 7.4%) in the low hematocrit group. CONCLUSION: Blood primes are instrumental in high-risk and low preoperative hematocrit patients in preventing cerebral oxygen desaturation during initiation and maintenance of CPB.

Aged↗

PubMed2005

Clinical performance and biocompatibility of novel hyaluronan-based heparin-bonded extracorporeal circuits.

We tested documented in vitro and ex vivo advantages of novel hyaluronan based heparin bonded extracorporeal circuits in a prospective randomized study. During the period from June until September 2005, 40 patients undergoing reoperation for coronary artery bypass grafting were allocated into two equal groups (n = 20): Group 1 was treated with hyaluronan-based heparin-bonded circuits and group 2 was treated with uncoated control circuits. Complete blood count, fibrinogen, albumin, C3a, interleukin-2 levels, and thromboelastographic data were documented after induction of anesthesia (T1) and heparin administration before cardiopulmonary bypass (CPB) (T2), 15 minutes after initiation of CPB (T3), before cessation of CPB (T4), 15 minutes after reversal with protamine (T5), and the first postoperative day at 8:00 a.m. (T6). Hollow fibers were collected for consecutive biomaterial analysis by optical and scanning electron microscopy (SEM). Desorbed protein deposition on fibers was compared by spectrophotometry. Leukocyte counts were lower in T4-T6 in group 1 (p < .05). Platelet counts demonstrated significant differences at T4 and T5 in coated group (p < .05). Albumin and fibrinogen levels were better preserved in Group 1 at T4, T5 and T4, T6, consecutively (p < .05). C3a and IL-2 levels were lower at T3-T5 and T4-T5 in intervention group (p < .05). Postoperative hemorrhage was 412 +/- 50 mL in group 1 and 684 +/- 50 ml in group 2 (p < .05). Respiratory support time was shorter in group 1 versus control (p < .05). Platelet adhesion was significantly lower in intervention group. Amount of desorbed protein was 1.44 +/- 0.01 mg/dL in group 1 and 1.94 +/- 0.01 mg/dL in control (p < .05). SEM and spectrophotometry demonstrated better surface preservation in the hyaluronan coated group. Novel hyaluronan-based heparin-bonded circuits reduce platelet adhesion-aggregation and protein adsorption and provide better perioperative clinical parameters through platelet, albumin, and fibrinogen-sparing effects.

Anticoagulants↗

PubMed2004

Clinical significance of coated extracorporeal circuits: a review of novel technologies.

Coating of extracorporeal circuits may be a solution to prevent adverse effects induced by the contact of blood elements and proteins with foreign surfaces. This paper reviews the recent novel coating technologies and compares their documented in vitro and ex vivo advantages under the clinical setting. Data presented have also been supported by postclinical biomaterial research to verify biocompatibility and hemocompatibility.

Cardiopulmonary Bypass↗

PubMed2004

Emerging technologies in biocompatible surface modifying additives: quest for physiologic cardiopulmonary bypass.

Modification of polymer surfaces to achieve a surface with enhanced compatibility is an important means of obtaining improved biomaterials. The molecular design of the novel technologies is carried out with attention to create a biomembrane-mimicking surface on medical devices. This review focuses on the comparison of the chemical composition of recent novel surface modifying additives and coating technologies, their biomaterial evaluation and clinical efficacy under the scope of our previous studies and current literature.

Biomimetic Materials↗

PubMed2002

Clinical performance and biocompatibility of poly(2-methoxyethylacrylate)-coated extracorporeal circuits.

BACKGROUND: Poly(2-methoxyethylacrylate) is an amphiphilic organic polymer consisting of a hydrophobic backbone with pendant hydrophilic groups that has been reported to reduce protein and platelet adsorption in in vitro and ex vivo studies. METHODS: Sixty patients undergoing three-vessel coronary artery bypass grafting were divided into two equal groups. Group 1 had operation with Capiox poly(2-methoxyethylacrylate) coated SX18R oxygenators with noncoated circuits, and group 2 had operation with all noncoated circuits. Hemodynamic variables, blood and urine test results, hematologic variables, complement fractions, C3a and C4d, and interleukin-6 levels were documented preoperatively (T1), on cardiopulmonary bypass (T2), before cessation of cardiopulmonary bypass (T3), after protamine sulfate reversal (T4), and on the first postoperative day (T5). Protein electrophoresis was performed at T1 and T5. Blood cell adhesion and aggregation on fibers were analyzed with optical microscopy, and desorbed protein was evaluated quantitatively by a spectrophotometer using samples obtained when the oxygenators were dismantled after cardiopulmonary bypass. RESULTS: Platelet counts in group 1 demonstrated significant differences at T3, T4, and T5 (p < 0.05) versus group 2 and white blood cell counts in group 1 versus group 2, at counts T4 and T5. Albumin levels were significantly better preserved in group 1 at T4, and T5 and fibrinogen levels, at T3 and T5 (p < 0.05). On electrophoresis, the postoperative albumin level was 57.9% +/- 3% in group 1 versus 50.2% +/- 3% in group 2 (p < 0.05). Postoperative hemorrhage was 452 +/- 35 mL in group 1 and 612 +/- 35 mL in group 2 (p < 0.05). Duration of intubation was significantly lower (p < 0.05) in group 1, as was need of blood transfusion (p < 0.01). More platelet adhesion and aggregation were demonstrated on noncoated oxygenator fibers. The amount of desorbed protein was 0.13 +/- 0.01 mg/dL versus 0.012 +/- 0.001 mg/dL (p < 0.001) on noncoated versus coated fibers, respectively. CONCLUSIONS: Poly(2-methoxyethylacrylate)-coated oxygenators reduce platelet adhesion, platelet aggregation and protein adsorption. This surface provides a better perioperative clinical status through platelet-, albumin-, and fibrinogen-sparing effects.

Acrylates↗

PubMed2002

The effects of vasoactive intestinal peptide on monocrotaline induced pulmonary hypertensive rabbits following cardiopulmonary bypass: a comparative study with isoproteronol and nitroglycerine.

BACKGROUND: Vasoactive intestinal peptide (VIP) has regulatory effects on myocardial and vasomotor functions usually demonstrated by in vitro or isolated heart studies. We studied in vivo effects in monocrotaline induced pulmonary hypertensive rabbits immediately after cardiopulmonary bypass (CPB) and tested them versus calcium channel and beta-blockers. METHODS: The study consisted of six groups (N=30; five rabbits/group): (1) Control with no pretreatment, monocrotaline injected groups: (solutions were perfused following termination of CPB for 60 min); (2) Control for pulmonary hypertension (PHT); (3) isoproteronol; (4) VIP 10(-6) M; (5) VIP 10(-5) M; (6) nitroglycerine. Normothermic CPB was instituted in thirty rabbits at a flowrate of 100 ml/kg/min for 120 min. Heart rate, mean arterial pressure (MAP), central venous, left atrium (LAP), pulmonary artery (PAP) pressures, pulmonary resistance (Rp), blood gases and ions were measured before and 15, 30, 45 and 60 min after CPB. The VIP 10(-5) M group was subjected to an additional 1.7 x 10(-6) M propranol and 2 mM verapamil infusions for a further 15 min. RESULTS: LAP, PAP, Qp, and Rp were significantly higher in the PHT control group (P<0.001). VIP 10(-5) M increased MAP and decreased PAP significantly with respect to isoproteronol and VIP 10(-6) M (P<0.05). VIP 10(-5) M also decreased Rp significantly in the early post CPB 15th minute (P<0.05), but did not show any superiority to other agents in the following minutes. Verapamil inhibited VIP 10(-5) M effects but propranol did not. CONCLUSION: VIP has dose responsive, positive inotropic and pulmonary vasodilatory effects in whole body CPB model acting via calcium channels.

Adrenergic beta-Agonists↗

PubMed2002

Surgical management of left ventricular aneurysms by endoventricular pericardial patch plasty.

BACKGROUND: Early and late surgical outcomes of endocardial resection and aneursymectomy repaired with an autologous pericardial patch were studied. METHODS: We studied 125 patients who underwent endoaneurysmorrhaphy with pericardial patch during the period from June 1993 until June 2000. Preoperative, early and late postoperative results, annual postoperative echocardiography of all patients and hemodynamic controls of 35 patients within a mean follow-up of 64+/-8 months were analyzed. RESULTS: Mean NYHA improved to postoperative 2.1+/-0.5 from preoperative 2.8+/-0.4. Mean number of bypass grafts was 2.6+/-1.1. Left ventricular ejection fraction rate improved to 36.2+/-8% in one month, 39.3+/-9% in 6 months, 42.3+/-8% in one year versus preoperative 29.2+/-9% (P< or =0.05).Perioperative mortality was 6.4% (eight patients) and 11 deaths were observed in the late follow-up (9.4%). CONCLUSION: Endoaneurysmorrhaphy with pericardial patch may be an alternative option in the management of left ventricular aneurysms within acceptable surgical results.

Aged↗

PubMed2002

Amiodarone versus digoxin and metoprolol combination for the prevention of postcoronary bypass atrial fibrillation.

OBJECTIVE: This prospective randomized study aims at evaluation and comparison of the prophylactic effects of amiodarone versus digoxin and metoprolol combination in postcoronary bypass atrial fibrillation. METHODS: A total of 241 consecutive patients undergoing elective coronary artery bypass grafting were randomly allocated into three groups. Patients in Group1 (n=77) received metoprolol 100 mg/24 h per oral (P.O.), preoperatively, 2x0.5 mg digoxin intravenously on the operating day and digoxin 0.25 mg P.O.+metoprolol 100 mg P.O. on the first postoperative day until discharge. Patients in Group 2 (n=72) received totally 1200 mg intravenous/24 h amiodarone which the 300 mg - bolus dose/1 h was given as soon as the operation had been finished. On the next day patients were administered 450 mg/24 h amiodarone i.v. and 600 mg/day in three doses P.O. were given until discharge. Group 3 (n=92) was the control group with no antiarrhythmic prophylaxis. RESULTS: Preoperative patient characteristics and operative parameters were similar in three groups. Atrial fibrillation occurred in 13 patients (16.8%) in Group 1, six patients (8.3%) in Group 2 and 31 patients (33.6%) in Group 3. CONCLUSION: Both study groups were effective in the prevention of postcoronary bypass atrial fibrillation with respect to control (P<0.01 in Group 1 and P<0.001 in Group 2).

Amiodarone↗

PubMed1994

Effect of Calcium Entry Blocking Agents (Nifedipine and Verapamil) on Myocardial Recovery during Reperfusion.

A comparative study on isolated guinea pig hearts was carried out to determine the effect of calcium entry blocking agents: nifedipine- and verapamil-added reperfusion solutions on myocardial recovery after global ischemia. After 20 min of normothermic ischemia, three groups of solutions were used for reperfusion (10 animals each): (1) Nifedipine-added (10--8 mmol L(minus sign1)) Krebs--Henseleit solution; (2) verapamil-added (10--8 mmol L(minus sign)) Krebs-Henseleit solution; (3) Krebs--Henseleit solution. Postischemic myocardial functions (ventricular contractile force and heart work) and enzyme activities were compared with their preischemic values. The addition of calcium entry blocking agents does not have any significant advantage over control solutions in myocardial recovery.

Journal Article↗