The Direct Myocardial Depressant Effect of Methylmethacrylate Monomer in vitro: Mechanical and Electrophysiological Actions / 대한마취과학회지

BACKGROUND: Methylmethacrylate monomer (MMA) bone cement has been associated with sudden systemic hypotension. The present study was aimed to explore the mechanism of direct myocardial depressant actions of MMA. METHODS: The isometric contraction of isolated guinea pig's right ventricular papillary muscle was measured. Normal and slow action potentials were evaluated by a conventional micro-electrode technique. The effects of MMA on sarcoplasmic reticulum (SR) function were evaluated by its effect on: rapid cooling contractures, rested state contraction of rat papillary muscle in normal Tyrode's solution and of guinea pig's papillary muscle in low Na+ Tyrode's solution. To measure the inward calcium currents (ICa), whole cell patch clamp techniques were applied. RESULTS: MMA caused a dose-dependent depression of the peak force (PF) and maximal rate of peak force (dF/dt-max). About a 30% depression of PF was shown at rested state (RS) contraction in rat myocardium and under low Na+ Tyrode's solution in guinea pig myocardium, respectively. In the 26 mM K+ Tyrode's solution, MMA caused dose-dependent depression of late force development without alteration in early force development. MMA depressed rapid cooling contracture accompanied by prolongation of time to peak contracture. MMA did not alter the amplitude or maximum depolarization rate of normal and slow action potentials. Action potential durations were significantly reduced. In patch clamp studies, MMA reduced ICa in a dose-dependent manner. CONCLUSIONS: MMA depressed cardiac contractility in a dose-dependent manner and may be partly related to the depression of Ca2+ influx through the cardiac membrane. SR Ca2+ release seems to be mildly inhibited by MMA. Based on common clinical concentrations, the direct myocardial depressant effect of MMA may not be a main cause of hypotension during an operation.

Cardiovascular and Respiratory Instability Induced by Excessive Packing during Lower Abdominal Surgery: A case report / 대한마취과학회지

Retractor and packing usually aid to expose the surgical field and fascilitate surgical procedures. but excessive packing can impede venous return and reduce cardiac output. We experienced severe hypotension and ventilatory difficulty associated with excessive packing and traction in a patient undergoing radical hysterectomy. After removing the packing and extracting the intestine exterior to abdominal cavity, patient's ventilatory condition improved immediately and cardiovascular stability was achieved.

Changes of Hemodynamics and Nitric Oxide during Liver Ischemia/Reperfusion of Pig / 대한마취과학회지

BACKGROUND: Surgical hepatic inflow obstructions such as the Pringle Maneuver (PM) or hepatic vascular exclusion (HVE) can reduce bleeding during hepatic resection, but ischemia/reperfusion injury of the liver and systemic hemodynamic changes are also inevitable during and after PM or HVE. Nitric oxide plays a pivotal role in ischemia/reperfusion injury. We evaluated hemodynamic changes and changes of nitric oxide during liver ischemia/reperfusion injury excluding the effects of intestinal ischemia. METHODS: Liver ischemia was induced by clamping of the portal triad, infrahepatic and suprahepatic inferior vena cava for 90 minutes. To exclude the effects of intestinal ischemia during liver ischemia, portal and iliac venous blood was bypassed to the jugular vein using a pump. Hemodynamic parameters and nitric oxide were measured serially; before and during ischemia, and after reperfusion. RESULTS: Mean arterial blood pressure (MAP) was well-maintained during ischemia, but after reperfusion, MAP, cardiac output (CO) and stroke volume (SV) significantly decreased (35 - 40, 30 - 40 and 30%, respectively) postischemia. Compared to preischemia, systemic vascular resistance and heart rate did not change after reperfusion. Pulmonary vascular resistance and mean pulmonary arterial blood pressure significantly increased (220 - 250% and 60 - 70%) after reperfusion. Nitric oxide (NO) did not change until 20 minutes after reperfusion, but after 40 minutes reperfusion, NO significantly decreased (20%) compared to preischemia. CONCLUSIONS: After 90 minutes warm liver ischemia/reperfusion causes hypotension induced by decreased CO and SV. Increased PVR seems to be the cause of decreased CO and SV. NO-SVR interaction does not seem to be the cause of postreperfusion hypotension.

The Effects of Ephedrine and Prehydration on the Cardiovascular Response during Spinal Anesthesia / 대한마취과학회지

BACKGROUND: This study was designed to compare the efficacy of an ephedrine intramuscular injection with crystalloid or colloid administration for the prevention of cardiovascular change during spinal anesthesia undergoing Transurethral Resection of Prostate (TURP). METHODS: Eighty ASA I-II patients scheduled for TURP under spinal anesthesia were randomly allocated to receive non of the vasopressors or fluids (control group), 40 mg of i.m. ephedrine (ephedrine group), 15 ml/kg of i.v. lactated Ringer'solution (crystalloid group), and 8 ml/kg of i.v. pentastarch(colloid group). 12 mg of 0.5% hyperbaric tetracaine was injected through a 24 gauge Quinke needle at the L4-5 interspace in all patients. All patients were placed in the supine position and blood pressure (BP) and heart rate were recorded at 1-min intervals for 10 min, 2-min intervals for the next 10 min and subsequently at 5-min intervals. The sensory level was determined by pin prick test using 27 gauge needle. RESULTS: In the ephedrine group, systolic blood pressure was significantly greater than the other groups between 1 and 40 min after spinal anesthesia. (p<0.05) The changes in diastolic BP, mean BP and heart rate in the all groups were similar. CONCLUSION: The result of intramuscular injection of ephedrine may be more effective than crystalloid or colloid adminstration for the prophylaxis of hypotension during spinal anesthesia undergoing TURP.

The Effects of Ephedrine and Prehydration on the Cardiovascular Response during Spinal Anesthesia / 대한마취과학회지

BACKGROUND: This study was designed to compare the efficacy of an ephedrine intramuscular injection with crystalloid or colloid administration for the prevention of cardiovascular change during spinal anesthesia undergoing Transurethral Resection of Prostate (TURP). METHODS: Eighty ASA I-II patients scheduled for TURP under spinal anesthesia were randomly allocated to receive non of the vasopressors or fluids (control group), 40 mg of i.m. ephedrine (ephedrine group), 15 ml/kg of i.v. lactated Ringer'solution (crystalloid group), and 8 ml/kg of i.v. pentastarch(colloid group). 12 mg of 0.5% hyperbaric tetracaine was injected through a 24 gauge Quinke needle at the L4-5 interspace in all patients. All patients were placed in the supine position and blood pressure (BP) and heart rate were recorded at 1-min intervals for 10 min, 2-min intervals for the next 10 min and subsequently at 5-min intervals. The sensory level was determined by pin prick test using 27 gauge needle. RESULTS: In the ephedrine group, systolic blood pressure was significantly greater than the other groups between 1 and 40 min after spinal anesthesia. (p<0.05) The changes in diastolic BP, mean BP and heart rate in the all groups were similar. CONCLUSION: The result of intramuscular injection of ephedrine may be more effective than crystalloid or colloid adminstration for the prophylaxis of hypotension during spinal anesthesia undergoing TURP.

The Effect of Acute Normovolemic Hemodilution on Cardiopulmonary Bypass in Coronary Artery Bypass Grafting Surgery / 대한마취과학회지

BACKGROUND: Systemic arterial hypotension is relatively common following initiation of cardiopulmonary bypass (CPB). Decreased blood viscosity is induced by acute normovolemic hemodilution (ANH) and by the use of crystalloid oxygenator prime. The purpose of this paper is to study the effect of ANH on mean arterial pressure, perfusion flow index and PaO2/FiO2 upon initiation of CPB, and on homologous blood usage during CPB in coronary artery bypass grafting (CABG) surgery. METHODS: We reviewed 30 patients constituting an ANH group, and 30 patients in a control group who had undergone CABG surgery within the past 2 years. In the ANH group, 1 or 2 units of fresh autologous whole blood were sequestrated following induction of anesthesia. We compared mean arterial pressure, perfusion flow index, PaO2/FiO2, and hematocrit on the initiation of CPB, and homologous blood usage during and post CPB periods between the groups. RESULTS: Upon initiation of CPB, hematocrit in the ANH group was significantly less than in the control group, but there was no significant difference in mean arterial pressure, perfusion flow index or PaO2/FiO2 between the groups. The use of homologous blood during CPB in the ANH group was not significantly higher than in the control group. CONCLUSIONS: Acute intraoperative normovolemic hemodilution in CABG surgery was safely performed without significant hypotension and increased homologous blood usage during CPB.

Hypotension Controlled by Infusion of Norepinephrine during Pheochromocytoma Excision: Case report / 대한마취과학회지

We report a case in which a 63-year-old male patient with pheochromocytoma developed persistent hypotension during surgery despite rapid volume replacement and administration of vasopressors. The patient was prepared for surgery with phenoxybenzamine for 13 days. Anesthesia was induced with thiopental sodium and maintained with N2O, O2, and enflurane. Sodium nitroprusside (SNP) was initiated and titrated based upon intraarterial blood pressure. Hypertensive episode during tumor manipulation was effectively managed by increased infusion of SNP. After surgical removal of tumor, this patient developed profound hypotension, which was aggressively managed by intravenous administration of crystalloid and blood as well as dopamine and epinephrine. However, this hypotension was persistent and aggravated. Accordingly, Infusion of norepinephrine (Levophed(R))was started and then the patient recoverd from his hemodynamic aberrations. We conclude that the cause of the persistent hypotension was cumulative and residual effect of preoperative phenoxybenzamine. Therefore, norepinephrine should be readily available for the treatment of hypotension resistant to other pharmacologic interventions.

Effect of 10% Pentastarch Preloading on Hemodynamic Changes during Transurethral Resection of Prostate (TURP) under Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Isotonic crystalloid solutions have been intravascularly administered before spinal anesthesia for prevention of spinal anesthesia induced hypotension in TURP, however many investigators have suggested that synthetic colloids administered before spinal anesthesia is more effective than equal volume of crystalloid solutions. In this study, effect of 10% pentastarch comparing with eqaul volume of crystalloid solution before spinal anesthesia on cardiovascular response were examined. METHODS: 30 patients undergoing elective TURP were randomly allocated to receive either 7 ml/kg of isotonic saline (saline group) or 7 ml/kg of 10% pentastarch (pentastarch group) for 15 minutes before spinal anesthesia. Blood pressure, heart rate and central venous pressure (CVP) were measured before and after operation. RESULTS: In pentarstarch group, systolic blood pressure and CVP were significantly higher than saline group untill 55minutes and 15 minutes after spinal anesthesia respectively. CONCLUSIONS: 10% pentarstarch administered before spinal anesthesia is more effective than equal volume of isotonic saline in TURP with respect to preserving blood pressure and CVP.