Morbidity and mortality of UNOS status 1B cardiac transplant candidates at home.

BACKGROUND: On January 20, 1999, UNOS listing regulations changed, allowing stable patients on inotropic support (Status IB) to be discharged home until cardiac transplant. The outcome, morbidity and cost savings of this new strategy has not been evaluated. METHODS: From 1/20/99 through 1/1/01, 155 patients were classified as UNOS Status 1B at our institution; 64 patients were never discharged and 91 were discharged home. Criteria for discharge were hemodynamic stability on low-dose, single-agent parenteral inotropic infusion, defined as dobutamine at a dose <7.5 microg/kg/min or milrinone <0.5 microg/kg/min. Data on re-admissions were collected prospectively. The frequency of complex ventricular arrhythmias was evaluated in a sub-group discharged with external or internal cardiodefibrillators (n = 38). RESULTS: Total Status I time to transplant for the 91 discharged patients was 139 +/- 91 days, with 87 +/- 67 days spent at home. Inpatient time to transplant was still high, with a mean of 51 +/- 45 days. The in-hospital time was comparable to that of the 64 patients who were never discharged (51 +/- 41 days). Fifty-nine percent of discharged patients were re-admitted, with 37% of patients requiring more than 1 admission. Sixty-six percent of admissions were for worsening heart failure (CHF), and 34% for infection or occlusion of the indwelling intravenous line. No significant arrhythmic events were recorded in the 38 patients who had internal or external cardiodefibrillators. Two patients died suddenly at home. One patient had declined to wear the external cardiodefibrillator. The other patient was not wearing the defibrillator at the time of the event, and in 634 hours of previous monitoring he had had no events. CONCLUSIONS: In UNOS Status 1B patients awaiting cardiac transplant on home inotropic therapy, mortality remains low but the re-admission rate was high. There appeared to be a low incidence of complex ventricular arrhythmias.     

The use of the novel calcium sensitizer levosimendan in critically ill patients

Levosimendan, a novel calcium sensitizer, enhances cardiac contractility by increasing myocyte sensitivity to calcium, and induces vasodilation. In this prospective observational study the haemodynamic effects of levosimendan in postoperative critically ill patients are reported. Twelve patients with the need for inotropic support were studied. One dose of levosimendan (12.5 mg) was administered at a rate of 0.1-0.2 microg kg(-1).min(-1), either alone or in addition to pre-existing inotropic therapy. Haemodynamic measurements were obtained at baseline, and at 3 h, 6 h, 12 h, and 24 h after the start of the levosimendan infusion. Levosimendan significantly increased cardiac output from (mean+/-SD) 4.3+/-0.91.min(-1) to 5.2+/-1.51 min(-1) after 24h (P=0.013), by increases in stroke volume (baseline 47+/-15 ml, after 24h 57+/-25 ml, P=0.05), as heart rate remained unchanged. Systemic vascular resistance decreased from 1239+/-430 dyn.sec.cm(-5) at baseline to 963+/-322 dyn.sec. cm(-5) at 24h (P<0.001). Pre-existing inotropic therapy present in ten patients remained unchanged or was reduced. In postoperative critically ill patients, infusion of levosimendan exerted favourable haemodynamic responses. Levosimendan increased cardiac output by increasing stroke volume, which might be attributed primarily to its inotropic properties. Due to its cyclic adenosine monophosphate independent positive inotropic effects, levosimendan may be of value as adjunctive therapy to other inotropic drugs in critically ill patients.     

Once weekly intraperitoneal therapy for gram-positive peritonitis

The pharmacokinetics and clinical outcome following a 30 mg/kg/2 L intraperitoneal (IP) dose of vancomycin, which was administered once a week for 3 weeks, was studied in ten continuous ambulatory peritoneal dialysis patients with peritonitis. Vancomycin was 91% absorbed following the first dose and rapidly achieved therapeutic serum concentrations, 19 +/- 8 mcg/mL at 1 hour and a peak of 37 +/- 8 mcg/mL at 6 hours. Vancomycin was eliminated slowly with a mean total clearance of 7 +/- 3 mL/min/70 kg and a distribution volume of 1.2 +/- 0.3 L/kg. The resultant mean serum t1/2 over the first week was 184 hours and the mean serum concentration at 168 hours was 10 +/- 4 mcg/mL. Based on the positive clinical outcome (100% cure) among patients with uncomplicated gram-positive peritonitis, the potential use of this alternative vancomycin dosing regimen is proposed.     

A prospective study of continuous intravenous milrinone therapy for status IB patients awaiting heart transplant at home.

BACKGROUND: We performed a prospective study to determine the feasibility and safety of continuous intravenous milrinone therapy administered at home in patients listed as Status IB for heart transplant. METHODS: Patients who were Status IB could participate if they met specific criteria including an optimal dose of milrinone < or =0.5 microg/kg/min, presence of an implantable cardioverter-defibrillator (ICD), and no other serious comorbidity. The primary end-point of the study was survival to transplant. Hospitalizations, quality of life and cost comparisons were assessed. RESULTS: From May 1999 through October 2002, a total of 60 patients (51 men, 9 women), aged 55.5 +/- 8.4 years, entered the study. Before milrinone therapy, cardiac index was 1.98 +/- 0.66 liters/min/m2 and peak oxygen consumption was 11.4 +/- 2.6 ml/kg/min. Mean time in the study was 160.1 +/- 151.8 days. Fifty-three patients (88.3%) underwent heart transplant. There were only 2 deaths during the study. There were 89 hospital admissions in 46 patients over the 43-month follow-up period; 58 of these admissions were for heart failure. There were 6 episodes of ICD firing for ventricular tachycardia. Quality-of-life measures in a sub-group of patients significantly improved 1 month after discharge. Substantial estimated cost savings occurred. CONCLUSIONS: Continuous intravenous milrinone therapy can be safely administered at home in selected patients with advanced heart failure who are listed for transplant. This strategy may be an acceptable alternative to prolonged hospitalization for patients dependent on continuous inotropic support. Re-hospitalization is to be expected. An implantable cardioverter-defibrillator should be present due to the incidence of ventricular tachycardia.     

Dobutamine increases heart rate more than epinephrine in patients recovering from aortocoronary bypass surgery.

To determine whether epinephrine might prove to be a cost-effective substitute for dobutamine, two 8-minute infusions of either epinephrine (10 and 30 ng/kg/min, n = 28) or dobutamine (2.5 and 5 micrograms/kg/min, n = 24) were administered to 52 patients recovering in the intensive care unit (ICU) after aortocoronary bypass (CABG) surgery. At the higher dose, both drugs significantly (P < .05) increased cardiac index (CI), epinephrine from 2.8 +/- 0.1 at baseline to 3.3 +/- 0.1 L/min/m2, and dobutamine from 3.2 +/- 0.1 at baseline to 4.1 +/- 0.2 L/min/m2. Epinephrine increased CI significantly less than dobutamine. Both drugs significantly increased stroke volume index (SVI), epinephrine from 32 +/- 1 at baseline to 36 +/- 1 mL/beat/m2, and dobutamine from 36 +/- 1 at baseline to 40 +/- 2 mL/beat/m2. At the higher dose, the effects of the two drugs on SVI were indistinguishable. On the other hand, while the higher dose of both drugs significantly increased heart rate (HR), epinephrine from 88 +/- 2 at baseline to 90 +/- 2 beats/min and dobutamine from 89 +/- 2 at baseline to 105 +/- 3 beats/min, the increase following the higher dose of dobutamine was significantly greater than that seen after epinephrine. Effects of the two drugs on mean arterial pressure, central venous pressure, pulmonary artery occlusion pressure, systemic vascular resistance, pulmonary vascular resistance, and left-ventricular stroke work did not significantly differ. Similar results were obtained in the subset of patients with baseline CI less than 3 L/min/m2 who more closely resembled patients who might acutely require inotropic drug administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical effects of use polymyxin B fixed on fibers in liver transplant patients with severe sepsis or septic shock

Polymyxin B (PMX-B) is a polycationic antibiotic, known to bind the lipid A portion of endotoxin, a cell wall component exclusively found in gram-negative bacteria (GNB). An extracorporeal hemoperfusion device (TORAYMYXIN) has been developed: PMX is covalently bound to the surface of an insoluble carrier material to inactivate endotoxin in blood without exerting toxicity on the brain or the kidney. The aim of this study was to evaluate the efficacy, safety, and clinical effects of direct hemoperfusion with an immobilized polymyxin B fiber column (DHP-PMX) among liver transplant patients with severe sepsis or septic shock. METHODS: From June 2004 to May 2005, 10 patients (6 men and 4 women) of overall mean age of 55 years (46-65 range) underwent orthotopic liver transplantation (OLT) and developed severe sepsis or septic shock according to The Consensus Conference of American College Physicians/Society of Critical Care Medicine (ACCP/SCCM) criteria. GNB were detected in all treated patients who received conventional antibiotic therapy, vasopressor or inotropic agents, and ventilatory support. The DHP-PMX treatment was performed three times in each patient. Hemodynamic and respiratory parameters and dosages of vasopressor or inotropic drugs were assessed at baseline and after each treatment. RESULTS: No adverse events occurred. From baseline to the third treatment the mean arterial pressure increased from 64 +/- 5 mm Hg to 89 +/- 4 mm Hg); while the dosages of dobutamine and norepinephrine were reduced: 6.4 to 1 mcg/kg/min and 1.3 to 0.001 mcg/kg per min, respectively. The PaO(2)/FiO(2) ratio increased: 214 to 291 mm Hg. CONCLUSION: The use of DHP-PMX may be an important aid in patients with sepsis in association with conventional therapy.     

Experiences of levosimendan as an inotropic agent in conjunction with passive containment surgery

OBJECTIVES: Levosimendan is a calcium sensitizer with a positive inotropic effect without increasing oxygen consumption. We have evaluated the immediate effects of levosimendan on cardiac index when given peri-operatively to patients with dilated cardiomyopathy in conjunction with passive containment surgery. DESIGN: Ten patients with dilated cardiomyopathy undergoing passive containment surgery with the ACORN Cardiac Support Device, either as the sole procedure or in combination with other open heart surgery, were after anaesthesia induction given levosimendan as a bolus dose of 12 microg/kg followed by an infusion of 0.1microg/kg/min for 24 hours. Cardiac index were measured before extra corporal circulation, immediately after extra corporal circulation, at arrival to the intensive care unit and on post operative day 1. The need for inotropic support was recorded. RESULTS: Nine of ten patients were preoperatively in a low cardiac output situation. At postoperative day 1 there was a significant increase in cardiac index from 2.1+/-0.1 to 2.8+/-0.2. CONCLUSIONS: This study confirms the theoretical benefits of levosimendan judged by an immediate significant positive effect on cardiac index.     

Amrinone in catecholamine refractory heart failure in septic shock

The effect of the new positive inotropic and vasodilatator bipyridine-derivate Amrinon on catecholamine-refractive heart insufficiency in septic shock is described. A bolus dose of 1 mg/kg b.w., followed by continuous infusion of Amrinon 10 micrograms/kg b.w./min improved the haemodynamic parameters of all seven patients. The severe tachycardia before therapy was diminished more than 30%, the blood-pressure increased about 25-30%. RAP, PAP and PCWP showed a diminution of 35-45%. The cardiac output increased nearly 100% under therapy. All patients had IPPV with high inspiratory oxygen concentration, with inversed-ratio-ventilation and high positive end-expiratory pressure. Under Amrinon-therapy the initial pulmonary insufficiency diminished. The oliguria/anuria existing before Amrinon-therapy was improved also. Amrinon was given over 24-36 hours, the total dose was between 800 and 1440 mg. Six of the seven patients survived their severe illness; one patient died of pulmonary embolism, confirmed by autopsy, four weeks after Amrinon-therapy.     

Circulatory changes in the sitting position during neurosurgical anaesthesia (NLA) (author's transl)

In 23 neurosurgical patients with haemodynamic effects of neuroleptanaesthesia in the supine (13 patients) and upright position (10 patients) were studied. The patients in the upright position demonstrated an increase of the mean arterial pressure of 19% and the total peripheral resistance of 45%, and simultaneously a decreased stroke index of 20% and the cardiac index of 16%. The stability of the circulation was preserved due to the increase of heart rate (to 90 +/- 17 beats/min) and total peripheral resistance. In spite of the almost identical average total dose of fentanyl in both groups (4.72 +/- 2.2 mcg/kg/h), supine position) and 4.97 +/- 2.23 mcg/kg/h, (sitting position), only the patient group in the supine position demonstrated a decrease of pulse rate of 36% to 65 +/- 20 beats/min with a decline of the cardiac index of 33% and unchanged stroke index. Our clinical observations and the animal studies of other authors allow the conclusion that during neuroleptanaesthesia in the upright position the baroreceptor-activity and the catecholamine secretion is not markedly reduced and consequently circulatory stability obtained. We regard neuroleptanaesthesia as the method of choice for neurosurgical operations in the upright position.     

Total intravenous anesthesia with remifentanil and propofol for implantation of cardioverter-defibrillators in patients with severely reduced left ventricular function

OBJECTIVE: To determine the cardiocirculatory effects of total intravenous anesthesia (TIVA) using remifentanil and propofol in high-risk cardiac surgical patients. DESIGN: Prospective study of 20 patients undergoing first-time implantation of a cardioverter-defibrillator (ICD). SETTING: Major, community, university-affiliated hospital. PARTICIPANTS AND INTERVENTIONS: In 20 patients with severely reduced left ventricular function (left ventricular ejection fraction <30%) undergoing first-time implantation of an ICD, TIVA using remifentanil and propofol was performed. MEASUREMENTS AND MAIN RESULTS: Extensive hemodynamic monitoring using a pulmonary artery catheter was performed: (T1) before induction of anesthesia, (T2) after intubation, (T3) after skin incision, (T4) after first defibrillation, and (T5) 10 minutes after extubation. Propofol, 3.0 +/- 0.6 mg/kg/h (range, 1.9 to 4.4 mg/kg/h), and remifentanil, 0.30 +/- 0.05 microg/kg/min (range, 0.21 to 0.40 microg/kg/min), were used. Total costs added up to US $44.60 per patient. Patients could be extubated within 12.5 +/- 4.2 minutes after stopping anesthesia. There were significant decreases in heart rate (HR; from 77 +/- 12 to 57 +/- 10 beats/min [T3]), mean arterial blood pressure (MAP; from 98 +/- 14 to 70 +/- 12 mmHg [T2]), and systemic vascular resistance (from 1,551 +/- 309 to 1,233 +/- 274 dyne x s x cm(-5) [T2]). Cardiac index (CI) slightly decreased only at T3 (from 2.46 +/- 0.42 to 1.92 +/- 0.29 L/min/m2; p = 0.04). The decrease in MAP could easily be treated by volume infusion in most patients (17 patients). Sixty-five percent of the patients needed dobutamine to increase CI to greater than 2.0 L/min/m2 (mean dose, 2.2 +/- 1.8 microg/kg/min). Dobutamine could be stopped before extubation in all patients. No patient needed sustained inotropic or ventilatory support and intensive care therapy could be avoided. CONCLUSION: TIVA using remifentanil and propofol in patients with severely reduced left ventricular function is safe, well-controllable, and allows early extubation after implantation of an ICD. Because patients without complications did not need a postoperative intensive care stay, costs may be considerably reduced.     

Postpartum gangrene of three limbs complicating inotrope therapy: A case report

BackgroundSymmetrical peripheral gangrene (SPG) is an uncommon but devastating complication in critically ill patients with a high mortality. It is seldom seen in pregnancy and postpartum period.Case presentationWe hereby report a 27-year-old woman diagnosed of having postpartum hemorrhagic shock. The patient developed symmetrical peripheral gangrene triggered possibly by sepsis and inotropes. The patient presented with consciousness disturbance and hemodynamically unstable condition. Owing to the unstable hemodynamic status, inotropic agents with maximum dose of dopamine at 17 mcg/kg/min and norepinephrine of 8 mcg/kg/min were used. On the 4th day of admission, the patient developed gangrene and compartmental syndrome in the limbs. However, even with the dose of inotropic agents tapered, the gangrene did not resolve. So, multiple amputations and fasciotomy were done. Patient also developed acute kidney injury with anuria, thus necessitating hemodialysis treatment.ConclusionAlthough postpartum hemorrhagic shock is of high risk for sepsis and use of inotropes is common, occurrence of peripheral gangrene is rare. A high index of suspicion for the diagnosis and timely intervention will prevent irreparable damage and loss of limb.     

Carvedilol improves functional class in patients with severe left ventricular dysfunction referred for heart transplantation

PURPOSE: Limited options are available to improve the functional class of patients awaiting cardiac transplantation. We assessed the effect of carvedilol on New York Heart Association (NYHA) class, heart rate (HR), blood pressure (BP), jugular venous pressure (JVP), electrolytes and renal function in patients with markedly decreased left ventricular (LV) function referred for cardiac transplantation assessment. METHODS: Sixty-one patients (age = 52 +/- 12 yr, EF = 23 +/- 7%, VO2 max = 16 +/- 5 mL/kg/min) referred to the cardiac transplant clinic were reviewed before and after the addition of carvedilol (starting dose 3.125 mg twice daily to target dose of 25 mg twice daily) to usual heart-failure therapy. Over a 1-yr period, at each visit prior to initiation, at baseline initiation visit and at each follow-up visit, NYHA class, BP, HR, JVP, electrolytes, and renal function were obtained. Statistical analysis was performed using random effects regression approach. A multiple logistic regression analysis was performed on 52/61 patients to determine possible associations between NYHA improvement and the following patient characteristics: sex, etiology of cardiomyopathy, initial NYHA class, and dose of carvedilol. RESULTS: Three patients died (2 after stopping carvedilol) and 3 were transplanted. Median follow-up was 100 d. Sixteen patients reached the target dose after a mean of 137 d (2.75 visits). Estimated time-to-target dose is 8 months (5.6 visits). BP tended to increase (p = 0.07 for change in trend) with no change in JVP, electrolytes or renal function. HR decreased 6 +/- 3 b.p.m. (p = 0.03). Of 14 patients NYHA class I/II at baseline, none were class III/IV at last follow-up visit. Of 47 patients NYHA class III/IV at baseline, 25 were class I/II, and 22 were class III/IV at last follow-up (p < 0.001). Multiple logistic regression analysis did not demonstrate any factor predictive of subsequent NYHA class improvement. CONCLUSIONS: Despite less than target doses in most patients, a favorable effect of carvedilol on functional class in patients with severe congestive heart failure (CHF) referred for transplant was observed. Those with good functional status remained stable and those with poor functional status improved or remained stable. No baseline patient characteristic predicted improvement. The shortage of donor organ requires optimal use of medical regimens which may improve functional class while awaiting transplantation and which may delay the necessity for heart transplantation. Therefore, addition of carvedilol to usual medical therapy may be beneficial even in patients with severe LV dysfunction and poor NYHA classification.     

The effects of nicardipine and verapamil on the recovery time of vecuronium-induced neuromuscular blockade]

The present study investigated the effects of intravenous therapeutic dose of either nicardipine or verapamil on the recovery from transient neuromuscular blockade produced by vecuronium in 21 adult patients scheduled for elective surgery. Neuromuscular function was evaluated by single twitch height (T1), an amplitude of activity of the ulnar nerve being evoked by an electrical stimulation (0.2 msec, 0.1 Hz) under N2O/O2 and halothane anesthesia. The patients given vecuronium were randomly assigned to one of 3 groups: a control group who received no Ca entry blocker, nicardipine group and verapamil group. Nicardipine (30 mcg.kg-1) or verapamil (50 mcg.kg-1) was injected when T1 reached to 10% of the control twitch height. The recovery time of vecuronium (the time between 25% and 75% recovery) was not different significantly among the control (9.4 +/- 3.7 min), nicardipine (8.5 +/- 3.1 min) and verapamil (9.8 +/- 4.3 min) groups. We conclude that a therapeutic dose of either nicardipine or verapamil could be safely given intravenously to the patients under vecuronium-induced neuromuscular blockade.     

The enhancement of hemodynamic performance in Fontan circulation using pain free spontaneous ventilation.

OBJECTIVE: Positive pressure ventilation is known to have a deleterious effect on pulmonary blood flow in patients with Fontan physiology. We evaluated the hemodynamic effects of pain free, spontaneous, non-positive pressure ventilation in patients undergoing Fontan staging procedures or completion. Fontan procedures, with creation of low pressure passive pulmonary circulation. METHODS: Between May 1997 and May 1999 50 consecutive patients undergoing either bi-directional Glenn (BDG, n=23) or completion Fontan (n=27), were managed with early extubation. Anaesthetic management included continuous narcotics, caudal block, epidural block, or hyperbaric spinal. Post-operative management included low dose dopamine (3 mcg/kg per min), nitro-glycerine (0.3 mcg/kg per min) and nitroprusside (0.3 mcg/kg per min). Post-operative management was identical for all patients. Twelve patients were randomly selected to undergo continuous cardiac output and cardiac index (CI) determinations utilizing extra vascular Doppler probes placed on the ascending aorta, allowing for continuous aortic diameter and Doppler wave form velocity recordings. All patients were extubated either in the operating room or within one hour post-operatively. There were no deaths and no complications in the series. Mean length of stay (LOS) for BDG was 4.3+/-0.5 days. Mean LOS for Fontan patients was 11+/-4 days. RESULTS: Mean pulmonary artery pressure (MPAP) fell from 19+/-3.464 pre-extubation to 14+/-3.271 immediately post-extubation, 13.2+/-2.261 6 h post-extubation, and 11.7+/-2.146 12 h post-extubation. All decreases in MPAP post-extubation were significant (P=<0.05). CI pre-extubation was 3.25+/-1.09, immediately post-extubation 5.05+/-1.297, 12 h post-extubation 6.225+/-1.19. All increases in CI post-extubation were significant (P=<0.05). CONCLUSION: Resumption of pain free, spontaneous, non-positive pressure ventilation enhances hemodynamic performance in patients with Fontan circulation and clearly improves outcome.     

Selected patients listed for cardiac transplantation may benefit from defibrillator implantation regardless of an established indication.

BACKGROUND: End-stage heart failure (HF) patients are at high risk of sudden cardiac death. This study evaluates the role of implantable cardiac defibrillators (ICDs) in HF patients awaiting cardiac transplantation. METHODS: We identified 194 consecutive patients (age 51 +/- 12 years) with New York Heart Association Class 3 or 4 HF (ejection fraction 22 +/- 9%) listed for cardiac transplantation, 35 of whom underwent ICD implantation. Of the implanted patients, 16 (Group A) had an established indication for ICD implantation (cardiac arrest, n = 10; sustained ventricular tachycardia [VT], n = 3; and positive electrophysiology study, n = 3). Nineteen patients (Group B) underwent ICD implantation for non-established indications (syncope with non-ischemic cardiomyopathy, n = 4; non-sustained VT, n = 15). There were no procedural complications from ICD implantation. RESULTS: During follow-up of 9.2 +/- 10.1 months, there were 3 deaths in the ICD groups (A and B), and 40 in the control group (8.6% vs 25.2%, p = 0.032). Five patients in Group A and 6 in Group B (31%) received appropriate ICD therapy. The number of therapies per patient and the time to the first shock were similar between Groups A and B. Four of 6 Group B patients on outpatient inotropic therapy (67%) received appropriate ICD therapy. CONCLUSIONS: Selected end-stage heart failure patients awaiting heart transplantation, including those without established ICD indications, are at high risk for malignant arrhythmias and may benefit from ICD implantation. Patients with ICD seem to have improved survival compared to those without ICD. Randomized prospective studies are needed to confirm these findings.     

Efficacy of intravenous administration of atrial natriuretic peptide after cardiac surgery in neonates and infants]

Intravenous infusion of alpha-human atrial natriuretic polypeptide (hANP) and furosemide was performed in 12 patients (4: TGA, 3: univentricular heart, 3: HLHS, 2: VSD) after cardiopulmonary bypass. Their mean age at the operation was 68 days (6 patients in neonate), the mean body weight was 3.3 kg. All patients were treated with nitroglycerin in dose of 2 micrograms/kg/min and chlorpromazine in dose of 2.8 micrograms/kg/min and catecholamine in mean dose of 6.5 micrograms/kg/min. The criteria of indication for hANP was poor effect of furosemide alone. The hANP was given for 6-144 hours in dose of 0.1-0.2 microgram/kg/min. With the hANP and furosemide infusion, urine volume increased from 85.0 +/- 14.2 ml/kg/day to 107.9 +/- 25.3 ml/kg/day (p < 0.05), whereas the systemic arterial pressure, the central venous pressure and the renal function were unchanged. We conclude that the combination of the hANP and the furosemide is very effective in neonates and infants.     

Comparison of dopamine and dobutamine therapy during intraaortic balloon pumping for the treatment of postcardiotomy low-output syndrome

Treatment of postcardiotomy low-output syndrome includes intraaortic balloon pumping (IABP), volume loading, pharmacological afterload reduction, and stimulation with an inotropic agent. This study compares the effectiveness of combined nitroprusside and dopamine therapy and nitroprusside and dobutamine therapy in 12 patients requiring IABP postoperatively. Serial hemodynamic measurements were made before and during infusion of nitroprusside and after administration of the combined therapy (N = 6 in each group). Prior to pharmacological therapy, cardiac index was 1.47 +/- 0.31 L/min/m2 and systemic vascular resistance (SVR) was 3,114 +/- 1,350 dynes sec cm-5 in patients subsequently given dopamine, and 1.59 +/- 0.38 L/min/m2 and 2,661 +/- 405 dynes sec cm-5, respectively, in those given dobutamine. With infusion of nitroprusside, both groups showed significant reduction in SVR. Nitroprusside plus either inotropic agent resulted in augmentation of cardiac index and an additional reduction in SVR, both changes being greater in the group given dopamine. Larger doses of dobutamine than dopamine were needed to achieve similar hemodynamic improvement. We conclude that the addition of an inotropic agent to vasodilator therapy during IABP results in a greater increase in cardiac index and a greater decrease in afterload than a vasodilator alone. In addition to its beneficial effect on renal perfusion at the dose required to effect these improvements, dopamine appears a better inotropic agent than dobutamine for postcardiotomy low-output syndrome.     

Continuous Positive Airway Pressure During Mechanical and Spontaneous Ventilation Effects on Central Haemodynamics and Oxygen Transport

The effect of continuous positive airway pressure during continuous mechanical (CMV + PEEP) and spontaneous (CPAP) ventilation on central haemodynamics and systemic oxygen transport was studied in 10 male patients who had undergone aortocoronary bypass graft operation 18 h earlier. With the change from CMV + PEEP 5 cmH2O to CPAP 5 cmH2O, cardiac index was found to increase from 2.58 +/- 0.44 (s.e. mean) to 2.88 +/- 0.19 l/min/m2 (P less than 0.005), and systemic oxygen transport improved from 8.5 +/- 0.6 to 9.5 +/- 1.0 ml/min/kg (P less than 0.05). Arterial oxygen tension and content did not change, but mixed venous blood oxygen tension increased from 3.5 +/- 0.2 to 4.2 +/- 0.2 kPa (P less than 0.005), reflecting the increase in cardiac output. Arteriovenous oxygen content difference decreased from 4.6 +/- 0.5 (CMV + PEEP) to 3.6 +/- 0.2 (CPAP) ml/100 ml (P less than 0.05), while total oxygen consumption remained unchanged. Mean systemic arterial pressure was found to increase from 10.8 +/- 0.4 to 11.6 +/- 0.4 kPa (P less than 0.05) and mean pulmonary arterial pressure changed from 2.2 +/- 0.1 to 2.4 +/- 0.1 kPa (P less than 0.05). Right atrial and pulmonary capillary wedge pressures did not change. Our observations suggest that, in terms of central haemodynamics and tissue oxygen supply, CPAP offers a noteworthy alternative weaning method and an alternative to CMV + PEEP in cases where therapy is prolonged and the patient is able to breathe spontaneously.     

Pharmacodynamics of high-dose vecuronium in children during balanced anesthesia.

To compare the speed of onset, intubating conditions, duration of action, and recovery from neuromuscular blockade with vecuronium to those with succinylcholine, 40 ASA physical status 1 or 2 children (ages 2-9 yr) were studied during N2O-O2-opioid anesthesia. Each child was randomly assigned to receive a bolus dose of one of the following muscle relaxants: succinylcholine 2.0 mg/kg (n = 10), vecuronium 0.1 mg/kg (n = 10), vecuronium 0.2 mg/kg (n = 10), or vecuronium 0.4 mg/kg (n = 10). The evoked electromyogram of the abductor digiti minimi to train-of-four stimulation was monitored. We found that with succinylcholine, the time to 95% twitch depression (speed of onset, mean +/- SD), 24 +/- 7 s, was significantly less than that with each dose of vecuronium: 0.1 mg/kg, 83 +/- 21 s; 0.2 mg/kg, 58 +/- 17 s; and 0.4 mg/kg, 39 +/- 11 s, respectively (P less than 0.05). The time to laryngoscopy and intubation did not differ significantly between succinylcholine (48 +/- 10 s) and vecuronium 0.4 mg/kg (57 +/- 13 s); however, both were significantly less than than with vecuronium 0.1 and 0.2 mg/kg (P less than 0.005). The intubating conditions were excellent in 100% of patients. The duration of action was least with succinylcholine (5.7 +/- 1.5 min) and increased with increasing doses of vecuronium: 0.1 mg/kg, 23.9 +/- 5.1 min; 0.2 mg/kg, 55.2 +/- 11.6 min; and 0.4 mg/kg, 74.6 +/- 9.9 min, respectively (P less than 0.001). The recovery index was most rapid with succinylcholine (1.6 +/- 0.4 min) and was slowest with vecuronium 0.4 mg/kg (22.6 +/- 2.1 min) (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of the degree of muscle blockade: a comparative study using electromyography of the muscular relaxation induced by pancuronium, atracurium and vecuronium

To compare the muscle relaxing effect of pancuronium, atracurium and vecuronium, 99 patients operated on under neuroleptanesthesia were divided in three groups depending on whether they had received, during induction, pancuronium 0.1 mg/kg, atracurium 0.5 mg/kg, or vecuronium 0.1 mg/kg. One-fourth of the initial dose was repeated if necessary. The electromyographic study of the muscle relaxing effect was carried out with stimulation of the cubital nerve with courses of supramaximal square wave electric stimuli in 'trains of four'. The time to maximal blockade (TMB), the time of clinical effectiveness (TCE), the total duration time (TDT), the time of duration of the maintenance dose (DM 25) and the recovery index (RI) were measured. TMB was 4.3 +/- 1 min for pancuronium, 3.5 +/- 0.8 min for atracurium, and 3.3 +/- 0.98 min for vecuronium. The differences between pancuronium and the other drugs were statistically significant, but they were not so between the latter two. TCE was 67.9 +/- 13.5 min for pancuronium, significantly longer than with vecuronium and atracurium (28.2 +/- 5.7 and 31.5 +/- 4.7, respectively). TDT was 126.2 +/- 19.9 min for pancuronium, 61.2 +/- 11.5 min for atracurium and 55.5 +/- 16.7 for vecuronium. The mean duration of the repeated dose was 52.7 +/- 8.4 min for pancuronium, 19.9 +/- 5 min for vecuronium and 10.9 +/- 5 min for atracurium. RI, which was similar for atracurium and vecuronium (12.7 +/- 1.7 min and 12.8 +/- 3.3 min), was longer for pancuronium (27.7 +/- 4.3 min).