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Biomedical subjects

L A Jacobs

Publications and source records attributed to L A Jacobs.

At least 37 records · Page 2Linked to original sources
PubMed1997

A novel protamine variant reversal of heparin anticoagulation in human blood in vitro.

PURPOSE: Protamine reversal of heparin anticoagulation during cardiovascular surgery may cause severe hypotension and pulmonary hypertension. A novel protamine variant, [+18RGD], has been developed that effectively reverses heparin anticoagulation without toxicity in canine experiments. Heretofore, human studies have not been undertaken. This investigation hypothesized that [+18RGD] would effectively reverse heparin anticoagulation of human blood in vitro. METHODS: Fifty patients who underwent anticoagulation therapy during vascular surgery had blood sampled at baseline and 30 minutes after receiving heparin (150 IU/kg). Activated clotting times were used to define specific quantities of [+18RGD] or protamine necessary to completely reverse heparin anticoagulation in the blood sample of each patient. These defined amounts of [+18RGD] or protamine were then administered to the heparinized blood samples, and percent reversals of activated partial thromboplastin time, thrombin clotting time, and antifactor Xa/IIa levels were determined. In addition, platelet aggregation assays, as well as platelet and white blood cell counts were performed. RESULTS: [+18RGD] and protamine were equivalent in reversing heparin as assessed by thrombin clotting time, antifactor Xa, antifactor IIa levels, and white blood cell changes. [+18RGD], when compared with protamine, was superior in this regard, as assessed by activated partial thromboplastin time (94.5 +/- 1.0 vs 86.5 +/- 1.3% delta, respectively; p < 0.001) and platelet declines (-3.9 +/- 2.9 vs -12.8 +/- 3.4 per mm3, respectively; p = 0.048). Platelet aggregation was also decreased for [+18RGD] compared with protamine (23.6 +/- 1.5 vs 28.5 +/- 1.9%, respectively; p = 0.048). CONCLUSIONS: [+18RGD] was as effective as protamine for in vitro reversal of heparin anticoagulation by most coagulation assays, was statistically more effective at reversal than protamine by aPTT assay, and was associated with lesser platelet reductions than protamine. [+18RGD], if less toxic than protamine in human beings, would allow for effective clinical reversal of heparin anticoagulation.

Aged↗
PubMed1997

Differential clinical workloads among faculty at a major academic health center.

OBJECTIVE: The authors analyzed patient care (1981-1995) and financial data (1991-1996) to determine if differential workloads existed at a major academic health center. SUMMARY BACKGROUND DATA: Academic health centers differ markedly from community-based medical centers, but they are required to compete with others who have a more circumscribed mission and a responsibility for providing less complex care. Changes in health care systems may lessen incentives to generate clinical revenue and may adversely affect educational and research programs. METHODS: Patient care data at the University of Michigan Health System were analyzed by discipline for level of activity from 1981 to 1995 and were compared to professional and institutional financial data from 1991 to 1995. RESULTS: Surgeons represented 11% of the total full-time physicians throughout the period of the study (94 of the 836 Medical Center physicians, 1995). They accounted for 33% of hospital admissions (11,616 of 35,101) and 16% of outpatient visits (92,364 of 568,738). Since 1981, surgeons experienced a 249% increase in total operative workload (6799-16,909 procedures), representing a 30% increase in operations/surgeon (138-180 operations). Surgical efforts in 1995 accounted for 29% of the total professional fee revenue and $240 million of the $512-million University of Michigan Hospital revenue. CONCLUSIONS: Surgeons had a greater collective and individual responsibility than did nonsurgeons for clinical activity and the financial viability of the academic health centers studied. Many proposals for financing health care delivery systems have the potential to exacerbate this differential. Restructuring of academic health centers must address this fact, lest their academic mission and scholarly activity be compromised.

Academic Medical Centers↗
PubMed1997

The oncology clinical nurse specialist in a post-master's nurse practitioner program: a personal and professional journey.

PURPOSE/OBJECTIVES: To examine the evolution of the advanced practice role in oncology nursing and the authors' educational experiences and role transitions as they progressed through a post-master's nurse practitioner (NP) certificate program. DATA SOURCES: Professional literature and personal experiences of two experienced oncology clinical nurse specialists (CNSs). DATA SYNTHESIS: Despite historical differences between CNS and NP roles, the authors did not subtract or detract from their CNS roles but added new skills to their established roles. CONCLUSIONS: Skills that define both the NP and CNS roles must be maintained to effectively meet the current healthcare needs of patients with cancer. IMPLICATIONS FOR NURSING PRACTICE: Many CNSs are returning to school to obtain their NP credentials. Although assimilating new skills and knowledge into an already established professional identity was a challenging undertaking, the authors viewed the experience as essential in preparing them to meet the demands of the changing healthcare environment.

Education, Nursing, Graduate↗
PubMed1995

Hepatic metabolic response to injury and sepsis.

BACKGROUND: Experimental reports have indicated that hepatic oxidative and synthetic metabolism may become depressed in sepsis. Because the mechanism of infection-related liver dysfunction has not been established, further study of these functional alterations could contribute to the therapeutic management of septic organ failure syndromes. However, recently controversy has arisen over the existence of these derangements that must be reconciled before further progress in this field can be made. METHODS: Splanchnic balance studies for the measurement of glucose output and oxygen consumption were used to assess hepatic function in fasted normal volunteers (n = 18), injured patients (n = 10), and patients with sepsis (n = 18). The liver's contribution to splanchnic metabolism was estimated from a comparison of splanchnic oxygen utilization in response to increases in the liver-specific process of glucogenesis. In addition, in vivo liver albumin production was determined by using the [14C] carbonate technique. RESULTS: Glucose output after injury and sepsis was increased by 12.8% and 76.6%, respectively, compared with controls. On the basis of substrate balance studies, gluconeogenesis was estimated to account for 46%, 87%, and 93%, respectively, of splanchnic glucose output in each of the three groups. In patients with sepsis glucose output was also noted to be linearly related to regional oxygen consumption, indicating that these processes were coupled and increases in the respiratory activity of the splanchnic cellular mass could be accounted for by increases in new glucose output and gluconeogenic substrate clearance. The mean albumin synthetic rate increased during injury and sepsis by 22% and 29%, respectively, compared with normal volunteers. CONCLUSIONS: These studies cast doubt on the commonly held notion that tissue respiratory dysfunction may occur during sepsis. On the contrary, hepatic function is accelerated during hyperdynamic sepsis, and evidence indicating oxidative or synthetic functional depression is lacking.

Adult↗
PubMed1993

Incorporating midmanagement skills in an oncology CNS program.

Today's health care system requires that CNSs be prepared to manage care within complex organizations as well as deliver expert care to individuals and their families. The integration of midmanagement preparation with clinical knowledge and skills is critical. In this paper, we (1) review the literature pertaining to the role of oncology CNS and management preparation, (2) describe the program at the University of Pennsylvania School of Nursing, and (3) identify the management content that was added to strengthen the theoretical and clinical components of the program and to prepare our graduates in assuming leadership positions.

Curriculum↗
PubMed1993

Effects of lumbar sympathectomy on canine transcutaneous oxygen tension.

Augmentation of cutaneous blood flow by postganglionic lumbar sympathectomy may not reflect an increase in nutritive vascular supply to the dermal tissues. Transcutaneous oxygen tension (TcPO2) was compared with radionuclide microsphere determination of dermal microcirculation in a hind limb sympathectomy model in 20 dogs. After 90 minutes the TcPO2 was greater in the sympathectomized limbs than in the contralateral limbs (125 mm Hg versus 114 mm Hg, p < or = 0.05). In contrast, microsphere-determined paw dermal capillary flow declined in sympathectomized limbs (4.9 ml/min/100 gm versus 11.8 ml/min/100 gm, p < or = 0.05). Decreases in the TcPO2/venous PO2 ratio correlated with sympathectomy-induced increases in total limb blood flow (r = 0.60; p < or = 0.001), reflecting less efficient oxygen extraction. These observations confirm the lack of enhancement of tissue oxygen delivery by sympathectomy because of the associated dilation of cutaneous arteriovenous shunts.

Animals↗
PubMed1991

Clinical characteristics and surgical management of vascular complications in patients undergoing cardiac catheterization: interventional versus diagnostic procedures.

The purpose of this report is to define the clinical characteristics and outcome of surgical management of vascular complications after interventional cardiac catheterization and to contrast them to those after diagnostic cardiac catheterization. From October 1985 to December 1989, 101 patients were treated for 106 vascular complications after 1866 interventional and 5046 diagnostic cardiac catheterizations at the University of Michigan Medical Center. Interventional catheterizations resulted in 69 vascular complications in 64 patients (frequency 3.4%). The most common interventions included coronary angioplasty (34), of which 10 required percutaneous partial cardiopulmonary bypass, intraaortic balloon pump placement (14), and aortic valvuloplasty (11). Interventional catheter-related complications included hemorrhage (33), arterial thrombosis (18), pseudoaneurysm formation (12), catheter embolization (2), thromboembolism (2), as well as arteriovenous fistula, pseudoaneurysm, and arterial dissection (1 each). Fifteen of these 69 patients (24%) had suffered acute myocardial infarction just before their catheterization. Surgical repair was performed under local anesthesia in 70% of patients. Major vascular reconstructions were required in 9% of patients. Three percent of the involved lower extremities had to be amputated because of complications occurring after arterial puncture. Eight percent of the patients incurring vascular complications after interventional procedures died after operation. Diagnostic catheterizations resulted in 37 vascular complications in 37 patients (frequency 0.7%). In contrast to diagnostic cardiac catheterization, vascular complications after interventional cardiac catheterization occurred more frequently, were most often due to hemorrhage at the vascular access site, and occurred in high-risk, critically ill patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Hepatic parenchymal oxygen tension following injury and sepsis.

Hepatic blood flow and splanchnic oxygen consumption were measured in 16 injured (n = 6) or septic (n = 10) patients and compared with values in 16 normal volunteers. Sepsis and injury appeared to stimulate an increase in blood flow and oxygen utilization, with the highest levels observed in the septic group. Patients with sepsis exhibited a 72% and 60% increase in hepatic blood flow and splanchnic oxygen consumption, respectively, compared with normal volunteers. Application of these data to the Krogh-Erlang tissue model indicates that despite an increase in oxygen delivery to the splanchnic bed during sepsis, it becomes more sensitive to hypoxic/ischemic events compared with other patient groups. This is indicated by a reduced centrilobular and increased critical oxygen tension. The major factor responsible for this is the regional hypermetabolism present in sepsis. This analysis emphasizes the critical importance of maintaining oxygen transport in critically ill patients with sepsis.

Humans↗
PubMed1990

Hepatic blood flow and splanchnic oxygen consumption measurements in clinical sepsis.

In an effort to characterize the hemodynamic response of the liver to sepsis, hepatic blood flow (HBF) was measured in 10 normal volunteers and compared with that of 9 patients with sepsis. Flow was determined according to two different indicators and three methods of analysis including indocyanine green dye clearance (HBFICG), galactose clearance (GC), and galactose clearance with splanchnic galactose gradient measurement (HBFGG). For normal subjects, these three analytic methods provided essentially identical results (HBFICG = 0.74 +/- 0.18, GC = 0.72 +/- 0.14, and HBFGG = 0.76 +/- 0.16 L/min-m2). With hepatic venous sampling, HBF in patients with sepsis was significantly higher than normal levels (HBFICG = 1.28 +/- 0.50 and HBFGG = 1.17 +/- 0.52 L/min-m2) (p less than 0.025), but HBF by the GC technique (0.89 +/- 0.41 L/min-m2), which uses peripheral venous sampling, was not significantly increased because of reduced splanchnic galactose extraction, which appears to be characteristic of sepsis. Thus HBF estimates based on peripheral venous sampling must be interpreted with caution in view of the reduced extraction fraction in sepsis. HBF in clinical sepsis tends to increase in response to this inflammatory stress.

Galactose↗
PubMed1989

Management of multiple enterocutaneous fistulas.

Enterocutaneous fistulas present a difficult management problem in the intensive care unit. Although some patients require surgical intervention for fistula control, key elements to good clinical management include mechanical control and vigorous nutritional support. This approach includes eradication of malnutrition, support of the hypercatabolic state, and maintenance or replacement of protein loss from fistula drainage. Good mechanical control involves integument protection and a mechanism of drainage collection. The patient we describe taxed the ingenuity and creativity of all those concerned with his care. Modification of a previously described technique to protect surrounding skin and collect fistula output served as a simple and inexpensive approach to eliminate infection potential, improve the patient's comfort, and decrease the nursing time that would have been required for frequent, complex dressing changes.

Aged↗
PubMed1989

Hemodynamic benefits of verapamil after aortic reconstruction.

Because of the high incidence of coronary artery disease (CAD) in patients undergoing aortic surgery, and because myocardial oxygen consumption is proportional to blood pressure x heart rate (HR) (pressure-rate product), it is important to prevent increases in these parameters postoperatively. The effect of verapamil, a calcium channel antagonist, on these parameters was evaluated in 30 patients undergoing abdominal aortic reconstruction. Postoperatively HR increased 27% in 19 patients without CAD and 47% in 11 patients with CAD. Pressure-rate product (blood pressure x HR) increased 17% and 31% in these two groups, respectively. Verapamil was able to reduce postoperative HR by 3% in patients without CAD and by 13% in patients with CAD. Verapamil reduced pressure-rate product 8% and 18%, respectively, in the two groups. These reductions were statistically significant in patients with CAD and occurred without reductions in cardiac output or left ventricular ejection fraction. Thus the postoperative increases in myocardial oxygen demand appeared to be primarily related to increased HR after aortic surgery, and these were reduced by verapamil without impairing blood flow or cardiac function.

Aged↗
PubMed1988

Insulinlike growth factor 1 production is inhibited in human sepsis.

We studied the response of 14 normal volunteers and five septic patients to a 48-hour course of exogenous biosynthetic human growth hormone (hGH) or placebo. Six normal controls (group 1) received saline, eight normal controls received hGH (group 2), and five septic patients also received biosynthetic hGH (group 3). Urinary urea excretion declined, and splanchnic amino acid uptake was maintained only in group 2 subjects. Septic patients exhibited changes in amino acid and urea dynamics comparable to those of subjects receiving placebo. Insulinlike growth factor 1 (IGF-1) production and plasma concentrations increased in group 2 in a fashion corresponding to the changes in nitrogen exchange, whereas septic patients exhibited no change in IGF-1 level. Therefore, in this septic patient group, exogenous hGH was ineffective in attenuating nitrogen losses and stimulating IGF-1 production. This supports the hypothesis that IGF-1 is a mediator of the anabolic effect of hGH.

Adult↗
PubMed1988

Central mixed and splanchnic venous oxygen saturation monitoring.

Central mixed venous oxygen saturation (SvO2) monitoring in critically ill patients to estimate adequacy of peripheral perfusion is gaining increasing popularity. However, a number of unexpected responses, one of which is marked depression of regional (splanchnic) venous oxygen saturation which may coexist with normal or high SvO2, makes interpretation of this parameter difficult. The SvO2 and hepatic venous oxygen saturation levels in seven injured (postoperative) and 15 septic patients were measured. No substantial differences between central and hepatic venous oxygen saturation was noted in nonseptic patients, however, septic subjects exhibited a normal SvO2 of 70.5% +/- 8.7% at a time when the hepatic venous saturation was 55.6% +/- 14.4% which is a significant (p less than 0.05) reduction. This reduced oxygen saturation was noted to arise from an increased regional metabolic rate rather than reduced perfusion. Nevertheless, we conclude that a flow limited regional oxygen consumption may potentially exist despite the presence of a normal SvO2 in certain patient subgroups such as septic subjects. Therefore, a normal SvO2 should not be considered as sole criteria to insure optimal oxygen delivery in critically ill patients.

Aged↗
PubMed1988

Primary microsurgery for postinflammatory tubal infertility.

Pelvic inflammatory disease is a common cause of tubal infertility. The pregnancy outcomes in 161 patients who underwent primary microsurgical tuboplasty for postinflammatory tubal disease at the Mayo Clinic from 1977 through 1981 were evaluated. The outcome (3-year rate) was evaluated for each category of microsurgical procedures. The proximal anastomosis group had a conception rate of 71% (50% live births, 30% spontaneous abortions, 6% ectopic pregnancies). The terminal salpingoneostomy group, which accounted for the largest number of procedures, had a conception rate of 47% (32% live births, 12% spontaneous abortions, 11% ectopic pregnancies). Even after microsurgical tubal reconstruction, most women do not achieve a live birth. Pregnancy outcome is probably related to several factors reflecting the severity of pre-existing intrinsic damage. Prognostic factors that may better predict pregnancy outcome are discussed.

Adolescent↗
PubMed1988

Initial clinical survey of the infertile couple.

This article is a basic overview of the initial evaluation of the infertile couple for the family practitioner. The physiology of conception and etiology factors are discussed. The comprehensive history, physical examination, and diagnostic evaluation of the infertile couple are discussed.

Female↗
PubMed1988

Altered T-lymphocyte subsets in severe sepsis.

To investigate the immune response of surgical patients to injury and sepsis, we measured total lymphocyte counts and T-cell subsets in five nonseptic and 17 septic subjects. Total lymphocyte and T-cell levels declined to similar degrees following injury or sepsis and did not appear to be of value as prognostic indicators. However, analysis of T-cell subsets in septic patients indicated that survivors exhibited normal T-cell subpopulations as well as helper to suppressor cell ratios. Nonsurvivors generally exhibited a selective depression of helper (OKT4) T-cells and the resultant degree of helper to suppressor ratio decline was directly related to mortality. A helper to suppressor ratio (OKT4/T8) below 0.6 was uniformly associated with a fatal outcome. Finally, a small subgroup of septic nonsurviving patients exhibited a selective depression of suppressor (OKT8) lymphocytes which also appeared to carry an unfavorable prognosis. These data indicate that T-lymphocyte subpopulation analysis is a useful predictor of hospital course.

Adult↗