Anthony J. DelRossi

Lorazepam and midazolam in the intensive care unit: a randomized, prospective, multicenter study of hemodynamics, oxygen transport, efficacy, and cost.

OBJECTIVES To evaluate and compare the clinical efficacy, impact on hemodynamic and oxygen transport variables, safety profiles, and cost efficiency of sedation and anxiolysis with lorazepam vs. continuous infusion of midazolam in critically ill, intensive care unit patients. DESIGN Multicenter, prospective, randomized, open-label study. SETTING Teaching hospitals. PATIENTS Ninety-five critically ill, mechanically ventilated patients with fiberoptic pulmonary artery catheters in place were randomly assigned to receive short-term (8 hrs) sedation with either intermittent intravenous injection lorazepam (group A, n = 50) or continuous intravenous infusion midazolam (group B, n = 45) titrated to clinical response. MEASUREMENTS AND MAIN RESULTS The severity of illness, demographic characteristics, levels of anxiety and agitation, hemodynamic parameters, oxygen transport variables, quality of sedation, nursing acceptance, and laboratory chemistries reflecting drug safety were recorded. There were no significant differences with regard to demographic data, hemodynamic and oxygen transport variables, or levels of anxiety/agitation between the two groups at baseline, 5 mins, 30 mins, and 4 and 8 hrs after administration of sedation. There were no significant differences in the quality of sedation or anxiolysis. Midazolam-treated patients used significantly larger amounts of drug for similar levels of sedation and anxiolysis (14.4 +/- 1.2 mg/8 hrs vs. 1.6 +/- 0.1 mg/8 hrs, p = .001). Both drugs were safely administered and patient and nurse satisfaction was similar. CONCLUSIONS Sedation and anxiolysis with lorazepam and midazolam in critically ill patients is safe and clinically effective. Hemodynamic and oxygen transport variables are similarly affected by both drugs. The dose of midazolam required for sedation is much larger than the dose of lorazepam required for sedation, and midazolam is therefore less cost-efficient.

Transfusion guidelines for cardiovascular surgery: Lessons learned from operations in Jehovah's Witnesses

Patients undergoing cardiovascular surgery are among the top users of homologous blood transfusion (HBT). Awareness of the risks of disease transmission and immune system modulation from HBT has prompted us to find alternatives such as autologous predonation (APD) and intraoperative autotransfusion (IAT). However, these latter options are not appropriate for all patients. We reviewed our experience with 59 Jehovahs Witness patients who underwent 63 elective cardiovascular procedures without either HBT or APD to determine the safety of operation without these modalities and to develop revised maximum surgical blood-ordering schedule guidelines for cardiovascular surgery. Estimated blood loss averaged 870 ml, but one third to one half of losses were replaced by IAT. IAT was not needed in lower extremity bypass operations in which the estimated blood loss was less than 150 ml. Three of 59 patients died (5.1%), but only one died of operative bleeding complications. We conclude that (1) elective cardiovascular operations can be done safely without the use of either HBT or APD, (2) HBT is not necessary in leg bypass procedures, and (3) maximum surgical blood-ordering schedule guidelines for HBT in major cardiovascular operations can be reduced to near zero by the use of intraoperative autotransfusion and acceptance of a postoperative hemoglobin nadir of 7.0 gm/dl.

Transfusion and surgery

In this survey of transfusion in surgery, we have attempted to provide the surgeon with an understanding of the problems associated with homologous transfusion and a practical knowledge of treatment strategies and alternatives designed to reduce homologous blood exposure. Such a review cannot be encyclopedic. Our hope is that it will serve the reader as a stimulus to examine his or her transfusion practices and as a guide for future self-learning.

Heparinless extracorporeal bypass for treatment of hypothermia.

In an attempt to assess the changes occurring to the coagulation profile during internal active core rewarming with partial cardiopulmonary bypass (CPB) without heparin anticoagulation, five pigs were anesthetized, and a model for severe to moderate hypothermia was created. Femoral-femoral bypass with Bio-Pump, heat exchanger, and a membrane oxygenator were used during the rewarming for 64.8 +/- 8.5 minutes. There were no statistically significant changes in platelet count, platelet index, activated clotting time (ACT), partial thromboplastin time (PTT), prothrombin time (PT), fibrinogen, fibrinogen index and fibrin split products (p greater than 0.05). There were no thromboembolic sequelae seen at autopsy. The components of the CPB circuit showed no signs of formation of aggregates or thrombi. The results of this study are attributed to the nonthrombogenic, atraumatic design of the Bio-Pump and the enhanced physiological fibrinolysis seen in the first hour of CPB. We concluded that heparinless CPB may serve as a safe alternative for active core rewarming for severe to moderate hypothermia.

Latissimus dorsi and serratus anterior dynamic descending aortomyoplasty for ischemic cardiac failure

Dynamic descending aortomyoplasty for cardiac assistance is a form of extraaortic, skeletal muscle-driven counterpulsation. Controversy exists regarding its clinical applicability and the most suitable muscle autograft for the procedure. Specifically, the ligation of intercostal vessels required for descending aortomyoplasty may not be tolerated clinically. This study compared the hemodynamic profiles and long-term function of latissimus dorsi (LD) aortomyoplasty to a split serratus anterior (SA) descending aortomyoplasty in which all intercostal vessels were preserved. Descending aortomyoplasty was performed in 11 goats. In 5, the SA was harvested and its distal end divided, facilitating a wrap of the aorta without ligation of intercostal arteries. In 6, the LD was used as a circumferential aortic wrap. At 90 days, an occluder placed on the left anterior descending artery created an ischemic event. Hemodynamic studies with and without assistance were performed in the ischemic and nonischemic states. Latissimus dorsi aortomyoplasty improved cardiac output 24% and 5.6%, stroke volume 29% and 66%, left ventricular stroke work index 30% and 166%, and coronary flow 4% and 3% in the normal and ischemic heart, respectively. Serratus anterior aortomyoplasty improved cardiac output 36% and 10%, stroke volume 42.8% and 13.5%, left ventricular stroke work index 64% and 21%, and coronary flow 8% and 4.3%, in the normal and ischemic heart, respectively. Two of the SA autografts were fibrotic and nonfunctional at 3 months. Aortomyoplasty with either SA or LD muscle improves cardiac function in the normal and ischemic heart. However, divided SA is associated with a higher rate of fibrosis and may be less suitable for the procedure.

Hemangioma of the right ventricular outflow tract

Obstruction of the right ventricular outflow tract by a primary cardiac tumor is rare. Six cases of right ventricular outflow tract obstruction by a primary cardiac hemangioma have been reported; all but one were detected before the age of 25 years. In this report, we review the literature and describe what we believe to be only the second reported case of right ventricular outflow tract obstruction produced by a cardiac hemangioma that presented in late adulthood.

Avoiding a catastrophe: Use of transesophageal echocardiography in diagnosing salmonella aortitis

Salmonella is now believed to be the most common organism causing infection in aortic aneurysmsl, ’ Salmonella organisms tend to colonize an arterial wall that has underlying disease, causing a local suppurative process and subsequently the formation of a pseudoaneurysm. The diagnosis can be difficult. We report a case of salmonella mycotic aneurysm of the thoracic aorta that was not accurately identified by multiple imaging techniques, including MRI, CT scan, and angiography, but was easily elucidated by transesophageal echocardiography (TEE) and confirmed by pathologic analysis after surgery. A 56-year-old white woman with a history of diabetes,

Long-Term Results of Simultaneous Carotid Endarterectomy and Coronary Artery Revascularization in Patients with Unstable Angina and Cerebrovascular Insufficiency

This study assessed the outcome of 11 consecutive high-risk patients (8 men, 3 women) with symptomatic, high-grade (greater than 70%) bilateral carotid stenosis and left main or triple-vessel disease with unstable angina undergoing emergency simultaneous carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) revascularization. Seven patients presented with crescendo unstable angina and 4 had type III postinfarc tion unstable angina. All were symptomatic for cerebrovascular insufficiency. Six patients had left main and 5 patients had triple-vessel disease aside from bilateral carotid lesions. There were 8 men and 3 women, (mean age 69.1 ± 3.9 years). The mean preoperative end-diastolic pressure and ejection fraction were 17.2 ±2.4 mm Hg and 35.3 ±6.9%, respectively. Sequential reconstruction of the carotid artery was followed by CABG with an average number of 3.1 ± 0.3 grafts per patient. One patient had additional aortic valve replace ment and 1 had an automatic implantable cardioverter defibrillator implanted. There was no operative mortality. The overall neurologic complication rate was 27.3% (3 of 11). One patient developed perioperative myocardial infarction and 1 other had respira tory failure. Mean postoperative hospital stay was 24.4 ±4.8 days. Within one year postoperation, 1 patient died. Two patients had contralateral CEA owing to recurrent transient ischemic attack. The five-year probability of survival was 89%. Our data show that simultaneous CEA/CABG in patients with high-risk coronary and cerebrovascular insufficiency may result in low mortality; however, a relatively increased incidence of short- and long-term morbidity is expected.

Improvement in Circulatory and Oxygenation Status by Perflubron Emulsion (Oxygent™ HT) in a Canine Model of Surgical Hemodilution

To examine the effect of a low dose of Oxygent HT on hemodynamics and oxygen transport variables in a canine model of profound surgical hemodilution, two groups of adult anesthetized splenectomized beagles were hemodiluted with Ringers solution to Hb 7 g/dL. The treated group received 1 mL/kg Oxygent HT (90% w/v perflubron emulsion [perfluorooctyl bromide], Alliance Pharmaceutical Corp.) and both groups (7 controls and 10 treated) were further hemodiluted using 6% hydroxyethyl starch until cardiorespiratory decompensation occurred. Pulmonary artery catheterization data and oxygen transport variables were recorded at Hb decrements of 1 g/dL breathing room air. There was no difference among groups during initial hemodilution. However, in the Oxygent HT group there was a statistically significant improvement in mean arterial pressure, CVP, cardiac output, PvO2, SvO2, DO2, and pulmonary venous admixture shunt during profound hemodilution to Hb levels of 6, 5, and 4 g/dL. A low dose of Oxygent HT offered benefit in improving hemodynamics and oxygen transport parameters even under air breathing conditions in a model of surgical hemodilution. This effect was most apparent at lower levels of Hb.

Improvement of spinal cord electrical activity with lazaroid (U74006F) during operations on the thoracic aorta: evaluation of a novel lipid peroxidation inhibitor

Reperfusion injury may contribute to spinal cord damage after cross-clamping of the thoracic aorta (AXC). Tirilazad (U74006F), a potent free radical scavenger and lipid peroxidation inhibitor, has proven to be beneficial in ischemia/reperfusion models. The authors investigated the efficacy of U74006F in preventing paraplegia following forty-five minutes of normothermic AXC distal to the origin of the left subclavian artery. Thirty-two mongrel dogs were assigned to receiving either vehicle as pretreatment (control, n = 7) or 1.5 mg/kg U74006F (group II, n=7) or 3 mg/kg U74006F (group III, n = 10) infused into the descending aorta distal to the clamp for twenty minutes during reperfusion, or 3 mg/kg U74006F IV as pretreatment twenty-five minutes before the onset of ischemia (group IV, n = 8). Mean proximal (BPpr) and distal (BPdx) aortic pressures and somatosensory evoked potentials (SEP) were measured at baseline and at minutes 2, 5, 7, 10, 15, 30, and 45 after AXC. SEP and neurologic outcome (Tarlov criteria) were assessed twenty-four hours postprocedure. There was no difference between BPpx or BP dx and their counterparts in the U74006F-treated animals and the control. SEP returned faster in all treatment groups when compared with controls. However, the neurologic outcome did not differ among groups. The authors conclude that although U74006F did not improve the neurologic outcome, it had a positive effect on the recovery of electrical activity of the spinal cord following transient ischemia. This suggests that the injury to the spinal cord induced by AXC is caused, in part, during reperfusion.