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Biomedical subjects

V A Ferraris

Publications and source records attributed to V A Ferraris.

At least 19 recordsLinked to original sources
PubMed1995

Limiting excessive postoperative blood transfusion after cardiac procedures. A review.

Analysis of blood product use after cardiac operations reveals that a few patients (< or = 20%) consume the majority of blood products (> 80%). The risk factors that predispose a minority of patients to excessive blood use include patient-related factors, transfusion practices, drug-related causes, and procedure-related factors. Multivariate studies suggest that patient age and red blood cell volume are independent patient-related variables that predict excessive blood product transfusion after cardiac procedures. Other factors include preoperative aspirin ingestion, type of operation, over- or underutilization of heparin during cardiopulmonary bypass, failure to correct hypothermia after cardiopulmonary bypass, and physician overtransfusion. A survey of the currently available blood conservation techniques reveals 5 that stand out as reliable methods: 1) high-dose aprotinin therapy, 2) preoperative erythropoietin therapy when time permits adequate dosage before operation, 3) hemodilution by harvest of whole blood immediately before cardiopulmonary bypass, 4) autologous predonation of blood, and 5) salvage of oxygenator blood after cardiopulmonary bypass. Other methods, such as the use of epsilon-aminocaproic acid or desmopressin, cell saving devices, reinfusion of shed mediastinal blood, and hemofiltration have been reported to be less reliable and may even be harmful in some high-risk patients. Consideration of the available data allows formulation of a 4-pronged plan for limiting excessive blood transfusion after surgery: 1) recognize the causes of excessive transfusion, including the importance of red blood cell volume, type of procedure being performed, preoperative aspirin ingestion, etc.; 2) establish a quality management program, including a survey of transfusion practices that emphasizes physician education and availability of real-time laboratory testing to guide transfusion therapy; 3) adopt a multimodal approach using institution-proven techniques; and 4) continually reassess blood product use and analyze the cost-benefits of blood conservation interventions.

Aspirin↗
PubMed1994

Resection of aortic arch aneurysms using an external shunt.

Surgical treatment of aneurysms of the thoracic aorta had its beginnings in the early 1950s. At that time, thoracic aneurysms were usually due to syphilitic infection and were usually fatal. Before the development of the heart-lung machine, it was realized that external shunts could facilitate the repair of these aneurysms. In 1954, Dr Ralph Alley and his colleagues at Albany Medical Center reported 2 patients who had surgical correction of thoracic aortic aneurysms using external vascular shunts. Both bovine aortic heterograft and human aortic homograft were used as aortic substitutes. These patients were presented at the Thirty-fourth Annual Meeting of the American Association for Thoracic Surgery in Montreal, Quebec, in May 1954, and case reports were subsequently published in the Journal of Thoracic Surgery in 1955. These presentations served as the stimulus for subsequent clinical studies and laboratory research, eventually leading to a better understanding of the physiologic principles involved in clamping the thoracic aorta. Doctor Alley's article is a classic in the field of cardiothoracic surgery and is now reviewed 39 years after its publication.

Aorta↗
PubMed1994

Home heparin therapy used in a pregnant patient with a mechanical heart valve prosthesis.

The optimal anticoagulation therapy for pregnant patients with a mechanical valve prosthesis is uncertain, but teratogenic effects and the high incidence of fetal loss associated with dicumarol derivatives limit the use of these agents as anticoagulants in this setting. A patient with a mechanical valve prosthesis, in the first trimester of pregnancy, stopped taking her warfarin because of personal fears about teratogenicity. Prosthetic valve thrombosis developed, and she required redo mitral valve replacement. Another mechanical prosthesis was inserted without maternal or fetal injury. The patient was maintained on continuous home, intravenous, high-dose heparin therapy for the remainder of her pregnancy. This therapy resulted in a successful pregnancy and delivery without valve thrombosis, hemorrhagic events, or maternal or fetal compromise.

Adult↗
PubMed1994

Traumatic thoracobiliary fistula.

Thoracobiliary fistulas are a commonly reported complication of subphrenic or liver abscesses and biliary tract obstruction. However, they are a rare and unusual complication of traumatic thoracoabdominal wounds. Due to their rarity, the experience of any one surgeon is minimal, and there is a paucity of information available in the literature regarding their treatment. We describe a case of a traumatic thoracobiliary fistula, review the existing literature, and discuss the proper management of this potentially lethal sequela of trauma.

Adolescent↗
PubMed1994

Assessment of flosequinan's direct effect on human arterial, venous, and cardiac muscle: comparison with other classes of agents used to treat heart failure.

We wished to provide comparative information regarding the direct effects of flosequinan, a novel quinolone under development for treating heart failure, on isolated human arterial, venous, and cardiac muscle. A similar assessment was made for four other agents--milrinone, ouabain, captopril and diltiazem--that have been used to treat heart failure patients, as well as for flosequinoxan, which is the primary metabolite of flosequinan. Flosequinan produced a potent and balanced relaxant effect on norepinephrine (NE)-contracted human arterial and venous smooth muscle, with IC25 values of 0.32 and 0.50 microM, respectively. At higher concentrations, flosequinan also produced a positive inotropic effect on human cardiac muscle (EC25 = 32 microM). A similar pattern of responses was observed with flosequinoxan. The pharmacologic profile obtained for the other agents examined differed from that observed with flosequinan and flosequinoxan in the following ways: Milrinone produced both vascular relaxant and positive inotropic effects, but at comparable concentrations; ouabain produced both vasoconstrictor and positive inotropic effects; diltiazem exerted a vascular relaxant effect at low concentrations and a negative inotropic effect at higher concentrations; and captopril had slight arterial relaxant and negative inotropic effects. These results demonstrate that the pharmacologic profile of flosequinan and flosequinoxan is unique as compared with that of other agents that have been used to treat patients with heart failure.

Captopril↗
PubMed1993

Relationship between inotropic activity and phosphodiesterase inhibition for flosequinan and milrinone.

The goal of this study was to assess the relationship between the positive inotropic response to high concentrations of the vasodilators flosequinan and BTS 53 554 (the sulfone metabolite of flosequinan) and the effect of both compounds on different forms of cyclic nucleotide phosphodiesterase. In addition, the relationship between inotropic activity and phosphodiesterase inhibition for the cardiotonic milrinone was also evaluated. All three agents exerted a positive inotropic effect on human cardiac muscle fibers. The concentration of milrinone required to increase cardiac contractility was comparable to the concentration required to inhibit the milrinone-sensitive subclass of cyclic AMP-specific phosphodiesterase (type III phosphodiesterase). However, no such relationship was observed for flosequinan and BTS 53 554. These results suggest that the cardiac response to high concentrations of flosequinan and BTS 53 554 is not mediated by inhibition of type III phosphodiesterase.

Humans↗
PubMed1993

Comparison of blood reinfusion techniques used during coronary artery bypass grafting.

A comparison of intraoperative autologous blood conservation techniques was carried out in 100 patients undergoing coronary artery bypass grafting. To facilitate comparisons of similar groups, patients were stratified into high-risk and low-risk groups based on the ratio of preoperative bleeding time to preoperative red blood cell volume. Our previous work suggested that patients with an elevated ratio have increased risk of excessive post-operative blood transfusion. We used this ratio to stratify the 100 patients to either the high-risk (39 patients) or low-risk (61 patients) strata. Within each stratum, patients were randomized to one of three groups: no intraoperative autologous blood conservation (control group), infusion of autologous platelet-rich plasma obtained from intraoperative plasmapheresis (PRP group), and infusion of autologous whole blood harvested immediately before cardiopulmonary bypass (whole blood group). Variables of postoperative blood loss and transfusion requirements were measured in each patient. Analysis of variance showed significant differences in blood product transfusions between groups. Patients in the high-risk stratum required significantly more blood product transfusions than those in the low-risk stratum (5.4 +/- 0.7 versus 2.0 +/- 0.6 units per patient; p < 0.001). In the high-risk stratum, PRP patients required significantly less postoperative blood transfusion compared with patients in the high-risk control group (2.9 +/- 2.1 versus 8.1 +/- 2.2 units per patient; p = 0.05). In the low-risk stratum, no intraoperative blood infusion method resulted in significant improvement in postoperative blood use.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Loss, Surgical↗
PubMed1993

Alternative conduits for coronary revascularization: a novel approach for harvest of the lesser saphenous vein.

Previous use of the greater saphenous vein limits the subsequent availability of conduit for coronary artery bypass grafting (CABG). One readily available alternative conduit is the lesser saphenous vein (LSV). During a 4-year period, 34 LSVs were explored in 23 patients using a novel surgical approach. The incision used for LSV harvest was carried through and deep into the muscular fascia, posterior to the tibia, along the length of the leg, developing a fascial-cutaneous flap. The LSV in all patients was imaged before operation by venous duplex scanning. Important anatomic details were mapped on the patient's leg before surgery using indelible ink. Findings at operation correlated well with the duplex imaging results. Of the 34 LSVs explored 31 were judged usable by the operating surgeon. In eight patients bilateral LSVs were used and in two this vein was the only conduit available. Among patients undergoing LSV harvest there was no operative mortality and minimal operative morbidity related to harvesting. Only one wound infection developed at the incision site. There were no documented cases of deep vein thrombosis. A case-control study was performed in which a control group of 25 patients undergoing CABG without use of the LSV were compared with the 23 who had LSVs harvested; patients in both groups underwent preoperative venous duplex studies. There were no significant differences in operative mortality or morbidity rate between groups (statistical power > 0.8 for these negative observations), suggesting that harvest of the LSV is usually successful when used in conjunction with preoperative venous duplex scanning.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Outcome in critical care patients: a multivariate study.

OBJECTIVE: To identify patient variables that were significantly associated with outcome in the ICU. DESIGN: Retrospective chart study of ICU patients. SETTING: Letterman Army Medical Center, Presidio of San Francisco. PATIENTS: A total of 110 consecutive patients who remained in the ICU for greater than 72 hrs. METHODS: Univariate analysis of 26 input variables, representing physiologic status and chronic health assessment at the time of ICU admission of the patients, and adverse events that occurred during their ICU stay. The dependent variable assessed was the outcome of patients after ICU intervention. A bad outcome included patient mortality or discharge from the ICU in worse condition or in a chronic vegetative condition. Five selected input variables were used in a multivariate logistic regression analysis to identify independent predictors of a successful outcome. RESULTS: Univariate statistical techniques comparing the values of 26 input variables of patients who improved during their ICU stay (46 patients) with those values of patients who did not improve (52 deaths and 12 unimproved patients) indicated that the following nine variables were significantly different in these two groups: a) age (p = .04), b) acute physiologic score (p = .047), c) Acute Physiology and Chronic Health Evaluation (APACHE II) score (p = .040), d) the number of repeat ICU admissions during a given hospitalization (p = .019), e) development of respiratory complications while in the ICU (p = .033), f) sepsis developing while in the ICU (p = .0001), g) renal failure developing while in the ICU (p less than .0001), h) disseminated intravascular coagulation while in the ICU (p = .0028), and i) the occurrence of any iatrogenic complication while in the ICU (p less than .0001). Five of these nine variables were used in a stepwise logistic regression analysis to develop a model to predict ICU outcome. This model showed the following three variables to be significantly associated with unfavorable ICU outcome: a) occurrence of any iatrogenic event while in the ICU (p less than .001), b) development of renal failure in the ICU (p = .001), and c) occurrence of sepsis while in the ICU (p = .042). A common iatrogenic complication associated with unfavorable ICU outcome was related to drug therapy (frequently aminoglycoside toxicity). Twenty-one iatrogenic drug complications occurred in 64 patients who did not improve in the ICU, whereas only three iatrogenic drug complications occurred in 46 patients who improved (p less than .001). CONCLUSIONS: For patients who remain in the ICU for greater than 72 hrs, events occurring after ICU admission are negatively associated with ICU outcome, more so than ICU admission status as reflected by such indices as APACHE II scores. Iatrogenic complications, often due to inappropriate drug therapy, have a significant association with adverse outcome by multivariate analysis. We suggest that iatrogenic complications influence ICU outcome, and that they are potentially preventable. By lessening their frequency, ICU outcome may be improved.

Age Factors↗
PubMed1989

Predictors of excessive blood use after coronary artery bypass grafting. A multivariate analysis.

One hundred fifty-nine consecutive patients who underwent coronary artery bypass grafting were studied to determine clinical and laboratory predictors of excessive postoperative packed red blood cell transfusion. Consideration of the distribution of packed red blood cells administered revealed that the patients could be divided into two groups: those patients who received 5 units of red blood cells or less (group I, n = 139) and those patients who received more than 5 units of packed red blood cells (group II, n = 20). The Mann-Whitney test or Fisher's exact test was used whenever appropriate to test differences between these two groups with respect to twelve patient variables. Patients in group II were found to have a significantly longer preoperative template bleeding time and decreased preoperative packed red blood cell volume (p less than 0.0008 for both variables). In addition, group II patients were significantly older (p = 0.026), were more likely to have had preoperative heparin therapy (p = 0.049), and contained a greater proportion of women (p = 0.0048). Of interest, variables that did not achieve statistical significance between groups were partial thromboplastin time, prothrombin time, platelet count, preoperative hematocrit level, urgency of operation, recent ingestion of aspirin, and recent heparin administration. All of the measured variables were used in a stepwise logistic regression analysis to identify the best predictors of the need for more than 5 units of packed red blood cells after operation. Of the variables examined, bleeding time (p less than 0.001; chi 2 improvement = 15.1) and red blood cell volume (p = 0.009; chi 2 improvement = 6.8) were the best predictors of excessive postoperative packed red blood cell use. On the basis of a 50% logistic probability level, the specificity and sensitivity of these two variables in predicting greater than a 5-unit transfusion requirement were 85% and 99%, respectively. A clinically useful nomogram based on this logistic model is presented. This nomogram suggests that a ratio of bleeding time to red blood cell volume of 0.0071 or greater is associated with a greater than 70% chance of requiring more than 5 units of packed red blood cells. We conclude that preoperative bleeding time and red blood cell volume are useful predictors of excessive postoperative blood transfusion. These results suggest that factors other than aspirin therapy may be associated with bleeding time prolongation leading to excessive postoperative transfusion.

Aged↗
PubMed1988

Preoperative aspirin ingestion increases operative blood loss after coronary artery bypass grafting.

Thirty-four patients were entered into a non-blinded, randomized study to test the effect of preoperative aspirin ingestion on postoperative blood loss and transfusion requirements after coronary artery bypass grafting. Sixteen patients in the aspirin-treated group had significantly increased chest-tube blood loss 12 hours after operation (1,513 +/- 978 versus 916 +/- 482 ml; p = 0.038). In addition, aspirin users had significantly increased requirements for postoperative packed red blood cells (4.4 +/- 3.5 versus 1.8 +/- 1.3 units; p = 0.014), platelets (1.3 +/- 1.3 versus 0.2 +/- 0.4 six-donor units, p = 0.0049), and fresh-frozen plasma (3.6 +/- 5.0 versus 0.78 +/- 1.6 units; p = 0.042) transfusions. The only patients requiring reoperation for bleeding were in the aspirin-treated group (2 patients). Six patients were not entered into the randomized part of the study because of excessively prolonged post-aspirin bleeding times (greater than 10 minutes). This finding suggests that a subset of patients are particularly sensitive to aspirin and have significantly prolonged bleeding times after aspirin ingestion. We conclude that aspirin ingestion increases postoperative blood loss and transfusion requirements, and we recommend discontinuation of aspirin therapy before cardiac procedures.

Aged↗
PubMed1988

Pericardial substitutes: a survey.

Many thoracic surgeons have used pericardial substitutes to reduce the risk of reoperation, but there have been few reports of these procedures. Therefore, we used a questionnaire to gather information on experience with use of pericardial substitutes and to document the findings at reoperation. A six-question survey was sent to 2,344 members of The Society of Thoracic Surgeons, requesting surgeons to list their experience with pericardial substitutes and at reoperation in patients with these substitutes in place. Of the 634 surgeons who responded to the survey, 120 reported the insertion of 3,828 pericardial substitutes. Two hundred thirty-six reoperations were reported by 89 surgeons. None of the pericardial substitutes was reported to be completely successful in facilitating reoperation. The experience with polytetrafluoroethylene (PTFE) pericardial substitutes was reported to be significantly more satisfactory than that with all other substitutes (p = 0.0004 by chi-square analysis), but 14% of surgeons who used PTFE said they were dissatisfied at reoperation. Based on the results of this survey, we suggest caution, careful documentation, and long-term follow-up studies before widespread use of pericardial substitutes can be recommended.

Biocompatible Materials↗
PubMed1987

Verapamil prophylaxis for postoperative atrial dysrhythmias: a prospective, randomized, double-blind study using drug level monitoring.

Orally administered verapamil hydrochloride (80 mg every 8 hours) or a placebo was given to 109 patients after coronary artery bypass grafting in a randomized, double-blind manner to test the efficacy of verapamil in preventing postoperative atrial dysrhythmias. The test drug was given through a nasogastric tube beginning 4 to 6 hours after operation until oral ingestion was possible. Serum levels of verapamil were measured at selected times after operation and when postoperative atrial dysrhythmias occurred. Postoperative atrial dysrhythmias occurred in 10 of the 53 verapamil-treated patients and in 20 of the 56 placebo-treated patients. Patients with verapamil drug levels higher than 150 ng/ml had fewer postoperative atrial dysrhythmias than those with lesser verapamil levels (p = .034) or than placebo-treated patients (p = .012). Only 2 of 31 patients with drug levels higher than 150 ng/ml experienced postoperative atrial dysrhythmias. Approximately 40% of verapamil-treated patients had drug levels lower than 150 ng/ml at 48 hours after operation. It is concluded that oral administration of verapamil prevents postoperative atrial dysrhythmias in a dose-dependent fashion.

Administration, Oral↗