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Biomedical subjects

L W Schultheis

Publications and source records attributed to L W Schultheis.

6 recordsLinked to original sources
PubMed1997

High dose neostigmine treatment of malignant sinus tachycardia.

Sinus tachycardia caused by circulating catecholamines in the setting of congestive heart failure may impair systemic perfusion because of decreased diastolic filling time. We report the case of a patient with Wolff-Parkinson-White syndrome with angina and cardiogenic shock who improved dramatically following administration of neostigmine. Cardiac output, blood pressure, and stroke volume increased as heart rate was reduced. A previous attempt at heart rate control, in the same patient, using a low dose beta-antagonist, precipitated hemodynamic collapse. The remarkable recovery of our patient suggests that acetylcholinesterase inhibitors may warrant further investigation in patients with severe sinus tachycardia.

Adult↗
PubMed1995

Efficacy of autologous fresh whole blood or platelet-rich plasma in adult cardiac surgery.

BACKGROUND: Transfusing fresh autologous blood during cardiac surgery may improve hemostasis and decrease the need for transfusion. STUDY DESIGN AND METHODS: A prospective randomized study was performed with fresh whole blood (WB) obtained by intraoperative hemodilution (IH) and with platelet-rich plasma (PRP) obtained by perioperative apheresis from adult cardiac surgery patients. RESULTS: Seventy patients were randomly assigned to three arms: 24 to the PRP arm, 18 to the IH arm, and 28 to serve as controls. A mean of 924 +/- 130 mL of WB was collected from the IH group, and a mean of 650 +/- 124 mL of PRP was collected from the PRP group (mean, 1.42 +/- 0.74 x 10(11) platelets); these components were transfused after bypass. Preoperative measures were similar among groups. Intraoperatively, the groups did not differ in bypass time, estimated blood loss, number of transfusions, or proportion receiving transfusion(s). Postoperatively, control patients had more mediastinal drainage (736 mL vs. 476 mL [IH] and 463 mL [PRP]; p = 0.014), but there was no difference in the proportion of patients requiring red cell transfusion (p = 0.87), the hemoglobin at discharge (p = 0.20), or the length of hospitalization (p = 0.57). CONCLUSION: Although a hemostatic benefit manifested as reduced postoperative bleeding was observed, this study does not support the use of fresh blood components obtained by IH or PRP collection during low-risk cardiac surgery. Additional studies are needed to assess whether more aggressive component collection or the use of these techniques in high-risk cases may have a greater impact on clinical outcome variables, including transfusion.

Adult↗
PubMed1993

Protamine and left ventricular function: a transesophageal echocardiography study.

The effect of protamine sulfate on left ventricular function was evaluated in 23 patients undergoing heart surgery requiring cardiopulmonary bypass (CPB). Ventricular function was assessed by measuring cardiac index with a thermodilution pulmonary artery catheter and fractional shortening with transesophageal echocardiography (TEE). After CPB, a heparin-neutralizing dose of protamine was infused continuously for 5 min. Hemodynamic variables were obtained and fractional shortening was measured before protamine administration (time 0), during protamine infusion (2.5 and 5 min), and after the infusion (10 and 15 min after the start of protamine). Patients with a preoperative ejection fraction > or = 50% had no statistically significant changes in either cardiac index or fractional shortening with protamine administration, when compared to time 0. However, patients with a preoperative ejection fraction < 50% had a significant decrease in fractional shortening which occurred during and immediately after protamine administration when compared to time 0 (P < 0.01), with no associated change in hemodynamics. Our results suggest that protamine may have a negative inotropic effect that is apparent in patients with impaired ventricular function.

Adult↗
PubMedDate not supplied

Voluntary, non-visual control of the human vestibulo-ocular reflex.

Voluntary control of the human vestibulo-ocular reflex with and without visual targets was investigated. Subjects were rotated sinusoidally from 0.1 to 1.0 Hz using d.c. electro-oculography to record eye position. The ratio of eye to head movement, or gain, of the vestibulo-ocular reflex was measured. When subjects were rotated in the dark at 0.3 Hz whilst performing mental arithmetic the gain was 0.65. When subjects were asked to fixate imaginary targets in the dark that were stationary in space, the gain rose to 0.95. When they imagined targets rotating with them on the chair, the gain dropped to 0.35. Our results indicate that the ability to modulate the gain of the vestibulo-ocular reflex does not depend entirely on the smooth pursuit system. Higher centers must modulate eye velocity so that it is appropriate to the subject's choice of a frame of reference, whether or not vision is available.

Adolescent↗