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Biomedical subjects

I Farquhar

Publications and source records attributed to I Farquhar.

9 recordsLinked to original sources
PubMed1996

Decreased capillary density in vivo in bowel mucosa of rats with normotensive sepsis.

Translocation of bacteria and endotoxin leading to sepsis occurs in animals subjected to burns or intestinal ischemia. This may be mediated in part by bowel mucosal microcirculatory dysfunction. However, the direct effect of sepsis on the mucosal microcirculation is unknown. The objective of this study was to develop a technique for intravital microscopy of the mucosa of the small bowel in an animal model of normotensive sepsis. We tested the hypothesis that normotensive sepsis induced by cecal ligation and perforation leads to a decrease in perfused capillaries in the small bowel mucosa at 24 hr. Twelve male Sprague-Dawley rats were hemodynamically monitored and randomly assigned to cecal ligation and perforation (CLP) or control laparotomy (sham). Twenty-four hours after initial surgery each animal was reanesthetized and the mucosal surface of the distal small bowel prepared for intravital microscopy. Laser doppler measurements of bowel wall blood flow were made immediately and repeated after a 30-min stabilization period. Intravital microscopy of the mucosal microcirculation of six villi per animal was performed and the images recorded on videotape (2 min/villus). The areas surrounded by perfused capillaries (intercapillary area) were then measured using video analysis software. Laser doppler flowmetry revealed a decrease in bowel wall blood flow during the stabilization period in the shams that did not occur in the CLP rats. The intercapillary areas were significantly greater in the CLP rats compared to sham rats (1329 +/- 316 microns2 vs 979 +/- 217 microns2, P = 0.044). The intercapillary areas were also more highly variable in the CLP group (median coefficient of variation 102 vs 83% in the sham group, P = 0.025). Intravital microscopy may be used to examine microcirculatory function of the small bowel mucosa. Sepsis induced by CLP leads to a decrease in the number of perfused capillaries in the small bowel mucosa.

Animals↗
PubMed1991

Cardiovascular reflex responses in Bangladeshi and European subjects.

1. Cardiovascular responses to three different interventions, namely the Valsalva manoeuvre, deep breathing and a cold stimulus on the face, were studied in two ethnic groups (European and Bangladeshi) that have been shown to differ in the prevalence of hypertensive-vascular disease. The data obtained consisted of systolic blood pressure, diastolic blood pressure, mean blood pressure, heart rate measured by using a beat-by-beat non-invasive blood pressure monitor (the Finapres), forearm blood flow determined by venous occlusion plethysmography, and calculated forearm vascular resistance. 2. The resting haemodynamic status was similar in European and Bangladeshi subjects. However, Bangladeshi subjects showed a greater increase in heart rate, but only after 20 s into the Valsalva manoeuvre, and greater overshoots in mean blood pressure after the manoeuvre than the European subjects. Furthermore, after cold face stimulation the fall in forearm vascular resistance to baseline levels was delayed in Bangladeshi subjects relative to that in the European subjects. 3. There were no inter-group differences in the reflex bradycardia relative to mean blood pressure or in the cardiac baroreflex sensitivity estimated from systolic blood pressure and pulse interval after the Valsalva manoeuvre. In addition, values for the mean difference between maximum and minimum pulse intervals during deep breathing did not differ in Bangladeshi and European subjects. 4. These findings together suggest that, although cardiac vagal reflex responses appear similar in the two groups, sympatho-adrenal influences on the heart and vasculature may be greater in Bangladeshi subjects than in European subjects.

Adult↗
PubMed1990

Sciatic block in lower limb surgery.

A series of cases is described in which sciatic nerve block (by the lateral approach of Guiardini et al., 1985), with or without femoral nerve blockade, proved useful in the manipulation of tibial and ankle fractures without recourse to general anaesthesia. A case is presented in which this approach was the method of choice.

Adolescent↗
PubMed1990

A simple flowmeter for unusual gases.

A flowmeter is described which may be used to measure gas flow in experimental situations. It may be adapted for use with any gas or gas mixture and be used to provide flows as small as 50 ml min-1. A mercury-in-glass manometer (sphygmomanometer) is used to measure the gas pressure proximal to a flow restrictor (consisting of a hypodermic needle hub) and it is this pressure head which, for a given gas, dictates the flow produced. This device may be produced at minimal cost in any hospital, is easy to calibrate and accurate.

Anesthetics↗
PubMed1988

Dantrolene in severe tetanus.

In its most severe form tetanus is treated with prolonged use of neuromuscular blockade, and artificial ventilation. We report a case in which the use of dantrolene sodium shortened the period of artificial ventilation.

Aged↗
PubMedDate not supplied

A Seldinger technique for the insertion of tunneled fixed-hub total parenteral nutrition catheters.

Total parenteral nutrition lines are commonly tunneled subcutaneously to decrease rates of sepsis. The history of line tunneling is discussed briefly, noting that to date a surgical approach, a detachable hub catheter or more recently a tunneling rod and 'peel away' introducer have been necessary for this form of central venous access. These systems have problems associated with cost, catheter type and insertion technique. A simple technique for insertion of tunneled total parenteral nutrition catheters is described. The device used consists of a polyurethane catheter with a fixed-hub. The applications of this approach are discussed.

Catheterization, Central Venous↗