Browsing by Author "Moran, S"
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- ItemArterial pressure-flow relationship in patients undergoing cardiopulmonary bypass(WILLIAMS & WILKINS, 1997) Urzua, J; Meneses, G; Fajardo, C; Lema, G; Canessa, R; Sacco, CM; Medel, J; Vergara, ME; Irarrazaval, M; Moran, SWe determined the arterial pressure-flow relationship experimentally by means of step changes of blood flow in 30 adult patients undergoing cardiopulmonary bypass (CPB). Anesthesia technique was uniform. CPB was nonpulsatile; hypothermia to 25-28 degrees C, and hemodilution to 18%-25% hematocrit were used. During stable bypass, mean arterial pressure was recorded first with blood flow 2.2 L.min(-1).min(-2). Flow was then increased to 2.9 L.min(-1).m(-2) for 10 s and reverted to baseline for 1 min. Then it was decreased to 1.45 L.min(-1).m(-2) for 10 s, and reverted to baseline for 1 min. Subsequently, it was decreased to 0.73 L.min(-1).m(-2) for 10 s and then reverted to baseline. line. Similar sets of measurements were repeated after 0.25 mg of phenylephrine and once the patient was rewarmed. The pressure-flow function was individually determined by regression, and the critical pressure estimated by extrapolation to zero flow. All patients had zero-flow critical pressure during hypothermia, with a mean value of 21.8 +/- 6.4 mm Hg (range 8.8-38.9). It increased after 0.25 mg phenylephrine to 25.4 +/- 7.2 mm Hg (range 12.2-43.9, P < 0.001). During normothermia, critical pressure was 21.2 +/- 5 mm Hg (range 13.4-30.9), not significantly different from hypothermia. During hypothermia, the slope of the pressure-flow function (i.e., resistance) was 14.9 +/- 3.5 mm Hg.L-1.min(-1).m(-2) (range 7.6-22.1). It increased significantly (P < 0.001) after phenylephrine, to 19.7 +/- 6.2 mm Hg.L-1.min(-1).m(-2) (range 11.4-40.5), and returned to 15.4 +/- 3.4 mm Hg.L-1.min(-1).m(-2) (range 10.1-24.2) during normothermic bypass. Systemic vascular resistance appeared to vary reciprocally with blood flow, although this finding may represent a mathematical artifact, which can be avoided by using zero-flow critical pressure in the vascular resistance equation.
- ItemComparison of isoflurane, halothane and fentanyl in patients with decreased ejection fraction undergoing coronary surgery(AUSTRALIAN SOC ANAESTHETISTS, 1996) Urzua, J; Serra, M; Lema, G; Canessa, R; Gonzalez, R; Meneses, G; Irarrazaval, M; Moran, SThe aim of the study was to compare three anaesthetic agents in patients with ejection fraction below 0.40 subjected to coronary revascularization surgery. Twenty-five elective coronary surgical patients with ejection fraction below 0.40 were prospectively studied. Premedication was pethidine 1 mg/kg and induction was fentanyl 0.03 mg/kg and pancuronium 0.1 mg/kg. The patients were randomized to one of three maintenance techniques (fentanyl, isoflurane or halothane).
- ItemLong-term results of repair versus replacement for degenerative mitral valve regurgitation(SOC MEDICA SANTIAGO, 2005) Zalaquett, R; Scheu, M; Campla, C; Moran, S; Irarrazaval, MJ; Becker, P; Arretz, C; Cordova, S; Braun, S; Chamorro, G; Godoy, IBackground- Mitral valve repair is considered better than mitral valve replacement for degenerative mitral regurgitation. Aim To evaluate late clinical results of;mitral valve repair as compared to mitral valve replacement in patients with degenerative mitral regurgitation. Patients and methods: All patients subjected to open heart surgery for degenerative mitral regurgitation between 1990 and 2002 were assessed for surgical mortality late cardiac and overall mortality, reoperation, readmission to hospital, functional capacity and anticoagulant therapy. Eighty eight patients (48 males) bad mitral valve repair and 28 (79 males) bad mitral valve replacement (23 with a mechanical prosthesis). Mean age was 59.9 +/- 14.8 (SD) and 61.3 +/- 14.6 years, respectively. Sixty three percent of patients with repair and 50% of those with, valve replacement were in functional class III or IV before surgery. Results: Operative mortality was 2.3% for mitral valve repair and 3.6% for mitral valve replacement (NS). Also, there was no statistical difference in the need of reoperation during the follow-up period between both procedures (2.3% and 0%, respectively). Ninety four percent of the replacement patients but only 269,6 of the repair patients were in anticoagulant tberapy at the end of the follow-up period (p < 0.001). Ten years survival rates were 82 +/- 6% for mitral valve repair and 54 +/- 1.1% for replacement. The corresponding cardiac related survival rates were 89 +/- 6% and 79 +/- 10%. At the end of follow-up, all surviving patients were in functional class I or II. Ten years freedom from cardiac event rates (death, cardiac related rehospitalization and reoperation) were 90 +/- 3% for mitral valve repair and 84 +/- 6% for replacement. Conclusion: Repair of the mitral valve offers a better overall survival and a better chance of freedom from cardiac events as well as need for anticoagulation 10 years after surgery (Rev Med Chile 2005; 133: 1139-46).
- ItemRenal protection in patients undergoing cardiopulmonary bypass with preoperative abnormal renal function(LIPPINCOTT WILLIAMS & WILKINS, 1998) Lema, G; Urzua, J; Jalil, R; Canessa, R; Moran, S; Sacco, C; Medel, J; Irarrazaval, M; Zalaquett, R; Fajardo, C; Meneses, GWe prospectively studied the effects of renal protection intervention in 17 patients with preoperative abnormal renal function (plasma creatinine >1.5 mg/dL) scheduled for elective coronary surgery. Patients were randomized to either dopamine 2.0 ,mu g.kg(-1).min(-1) (Group 1, n = 10) or perfusion pressure >70 mm Hg during cardiopulmonary bypass (CPB) (Group 2, n = 7). Glomerular filtration rate and effective renal plasma flow were measured with inulin and I-125-hippuran clearances before the induction of anesthesia, after sternotomy and before CFB, during hypo-and normothermic CPB, after sternal closure, and 1 h postoperatively. Plasma and urine electrolytes were measured, and free water, osmolar, and creatinine clearances, as well as fractional excretion of sodium and potassium, were calculated ed before and after surgery. Significant differences between groups were found before CPB for glomerular filtration rate (higher in Group 1), urine output (2.0 vs 0.29 mL/min in Group 1 versus Group 2), urinary creatinine (66 vs 175 mg/dL), urinary osmolarity (370 vs 627 mOsm/L), osmolar clearance (2.1 vs 0.7 mL/min), and urinary potassium (33 vs 71 mEq/L). There were no differences between groups during hypo-and normothermic CPB. After CPB, the only difference was a slightly higher urinary creatinine in Group 2. Renal plasma flow was lower than normal in all patients before the induction of anesthesia. A nonsignificant trend toward increased flow was seen during hypothermic CPB. Filtration fraction was high before CPB, which suggests efferent arteriolar vasoconstriction, descending toward normal during and after CPB. The same pattern of changes was present in both groups. In conclusion, there were no clinically relevant differences between the two treatment modalities during and after CPB. However, significant differences were observed before CPB, when dopamine seemed to partially revert renal vasoconstriction. Implications: Two protective interventions were compared in patients undergoing heart surgery to prevent deterioration of renal function; these were dopamine infusion throughout the operation and phenylephrine infusion during cardiopulmonary bypass. We found clinically relevant differences only during surgery before cardiopulmonary bypass.
- ItemValve repair surgery for incompetent bicuspid aortic valves(SOC MEDICA SANTIAGO, 2005) Zalaquett, R; Campla, C; Scheu, M; Cordova, S; Becker, P; Moran, S; Irarrazaval, MJ; Baeza, C; Arretz, C; Braun, S; Chamorro, G; Godoy, I; Yanez, FBackground Surgical valve repair is a good alternative for correction of incompetent bicuspid aortic valve. Aim: to report the early and late surgical, clinical and ecochardiographic results of surgical repair of incompetent bicuspid aortic valves. Patients and methods: Retrospective review of medical records of 18 patients aged 19 to 61 years, with incompetent bicuspid aortic valve in whom a valve repair was performed. Four patients had infections endocarditis and 17 were in functional class I or II. Follow up ranged from 3 10 113 months after surgery. Results: A triangular resection of the prolapsing larger cusp, which included the middle raphe, was performed in 17 cases, in 73 of these, a complementary subcommisural annuloplasty was performed. In the remaining case, with a perforation of the non-coronary cusp, a pericardial patch was implanted; this procedure was also performed in 2 other cases. In 3 cases large vegetations were removed. Postoperative transesophageal echocardiography showed no regurgitation in 11 patients (62%) and mild regurgitation in 7 (38%). There was no operative morbidity or mortality. There were no deaths during the follow-up period. In,3 patients (17%) the aortic valve was replaced with a mechanical prosthesis, 8 to 108 months after the first operation. Reoperation wets not needed in 93% 6,4% at 1 year and 85% 9,5% at 5 years, these patients were all in functional class 1 (it the end of the follow-lip period. 60% bad no aortic regurgitation, 20% had mild and 20% moderate aortic regurgitation on echocardiographic examination. A significant reduction of the diastolic diameter of the left ventricle was observed but there were no significant changes in systolic diameter or shortening fraction. Conclusions Surgical repair of incompetent bicuspid aortic valves has low operative morbidity and mortality and has a low risk of reoperation.