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Biomedical subjects

S Crofts

Publications and source records attributed to S Crofts.

8 recordsLinked to original sources
PubMed2001

Dimeric W3SO3 cluster complexes: synthesis, characterization, and potential applications as X-ray contrast agents.

Our continued research on the use of heavy metal cluster complexes as a new class of X-ray contrast agents in medical diagnostic imaging is described. A series of 2:3 cluster-ligand complexes, [(W(IV)3SO3)2L3]4- (L = linear polyaminopolycarboxylate ligands), were isolated from the reaction of aqua ion [W(IV)3SO3(H2O)9]4- (prepared in large quantities through an improved literature process) with respective ligands in refluxing DMF. The salts of [(W(IV)3SO3)2L3]4- complex anions were fully characterized using routine techniques such as elemental analysis, MS, HPLC, UV-vis, IR, and NMR. The solid structures of two complex anions, [(W(IV)3SO3)2(PDTA)3]4- and [(W(IV)3SO3)2(HO-PDTA)3]4-, were determined by X-ray crystallography. They are the first examples wherein two W(IV)3SO3 clusters are complexed and linked by three ligands that contain two terminal iminodiacetate (bis-IDA) groups. Complexation of the unstable aqua ion [W(IV)3SO3(H2O)9]4- with ligands has imparted desired biological compatibility to the tungsten metal cluster. These complexes are stable and highly soluble in H2O. The potential utility of such tungsten cluster complexes as X-ray contrast agents was evaluated in both in vitro and in vivo animal studies. In addition, the syntheses of several new linear polyaminopolycarboxylate ligands used in this study are reported.

Animals↗
PubMed2001

Central and peripheral adverse hemodynamic changes during laparoscopic surgery and their reversal with a novel intermittent sequential pneumatic compression device.

OBJECTIVE: To study the influence of a novel intermittent sequential pneumatic compression device (Lympha-press) on the adverse cardiac and peripheral hemodynamic changes induced by positive-pressure pneumoperitoneum (PPPn) in laparoscopic surgery. SUMMARY BACKGROUND DATA: Creation of PPPn is known to cause adverse central and peripheral hemodynamic changes. An intrasubject observational study was undertaken to quantitate these adverse changes and to assess the influence of an intermittent sequential pneumatic compression system on these adverse hemodynamic changes during laparoscopic surgery with PPPn. METHODS: The study involved 16 consecutive patients undergoing laparoscopic surgery with PPPn of 12 mmHg and 30 degrees head-up tilt position. The following peripheral hemodynamic recordings were made using Doppler ultrasound: peak systolic velocity (PSV), end diastolic velocity (EDV), and cross-sectional area of the femoral vein. Central monitoring included cardiac output and stroke volume by transesophageal Doppler, blood pressure, and pulse. The hemodynamic state based on these parameters was assessed before induction of PPPn with the anesthetized patient in the supine position, after induction of PPPn and head-up tilt position with Lympha-press off, and during PPPn and head-up tilt position with Lympha-press on, and after desufflation with the patient in the supine position under general anesthesia. RESULTS: Positive-pressure pneumoperitoneum and the head-up tilt position resulted in a 33% reduction in PSV, a 21% reduction in EDV, and a 29% increase in cross-sectional area of the femoral vein. This was associated with a 20% reduction in cardiac output and an 18% reduction in stroke volume. Activation of Lympha-press during PPPn and the head-up tilt position resulted in a 129% increase in PSV and a 55% increase in EDV by 55%. It also increased the cardiac output by 27% and stroke volume by 16%, with no effect on cross-sectional area. Compared with the pre-PPPn stage, there was no difference in cardiac output or stroke volume, but the PSV was higher by 78% and the EDV by 32%. After abdominal desufflation in the supine position, the cardiac output and stroke volume were restored to the pre-PPPn level, but persistent and significant elevations were observed during the period of study in PSV, EDV, and cross-sectional area. CONCLUSIONS: Significant and individually variable central and peripheral hemodynamic changes are encountered during laparoscopic surgery with PPPn and the head-up tilt position. These are reversed by intermittent sequential pneumatic compression using Lympha-press.

Adult↗
PubMed1996

Computed tomographic analysis of airway dimensions after carotid endarterectomy.

Airway obstruction is a rare but serious postoperative complication of carotid endarterectomy. We prospectively studied airway dimensions between the hyoid bone and cricoid cartilage in patients undergoing carotid endarterectomy using preoperative and postoperative computed tomographic (CT) scans of the neck. CT scans showed soft tissue swelling in all 19 patients. Five patients with clinical evidence of airway obstruction and a hematoma present on CT scan were intubated postoperatively. The three-dimensional reconstruction of the neck from the CT scans showed a reduction in the volume of the airway in all patients. This reduction was greater in the intubated (62% +/- 9%) compared to the nonintubated (32% +/- 7%) patients (P < 0.01). The anterior-posterior and transverse diameters of the airway were reduced, while retropharyngeal edema was increased after carotid endarterectomy. This change was greater for the upper airway at the level of the hyoid compared to the arytenoids and cricoid, and was significantly greater in the intubated than the nonintubated patients. Tracheal deviation was greater in the intubated than in the nonintubated patients. These results demonstrate significant soft tissue edema of the neck after carotid endarterectomy that reduces airway volume and can result in airway obstruction.

Aged↗
PubMed1992

The minimum effective dose of lignocaine to prevent injection pain due to propofol in children.

In a single-blind study of 100 children aged 1 to 10 years, the minimum effective dose of lignocaine required to prevent injection pain due to propofol was 0.2 mg.kg-1 when veins on the dorsum of the hand were used. This is more than twice the adult value. We concluded that injection pain should not limit the use of propofol in children if an adequate amount of lignocaine is mixed immediately prior to injection.

Anesthesia, Intravenous↗
PubMedDate not supplied

Developing a quality management strategy.

A collaborative strategy between a college of nursing and a specialist nursing service was devised using outcomes driven by the ENB Higher Award. The successful implementation of this strategy has shown that the expectations of increased clinical-based innovation, resulting from this new approach to practitioner development, are achievable.

Humans↗