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Biomedical subjects

M C Bellamy

Publications and source records attributed to M C Bellamy.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effect of graft reperfusion on intracellular calcium levels in mononuclear leucocytes during human orthotopic liver transplantation.

BACKGROUND: Orthotopic liver transplantation (OLT) is accompanied by local and systemic manifestations of the ischaemia-reperfusion syndrome. Local effects are mediated in part through changes in intracellular calcium levels in Kupffer cells. Arachidonic acid metabolites mediate increases in intracellular calcium concentration and thus potentiate the effect of free radicals. This study was carried out to characterize white blood cell (WBC) calcium changes as a mediator for white cell activation in human OLT. METHODS: Twenty consecutive patients had OLT using standard surgery and anaesthesia techniques. Blood samples were drawn for estimation of WBC cytosolic calcium content at induction of anaesthesia, 5 min before graft reperfusion and 15 min after reperfusion. The rate of rise in intracellular calcium concentration after the addition of a calcium chloride 1 mmol L(-1) solution to the extracellular milieu was used as an estimate of membrane calcium permeability. RESULTS: Both extracellular (P = 0.0002) and intracellular (P = 0.0008) calcium concentrations rose with time. However, at no time was there a correlation between extracellular and intracellular calcium levels or rate of calcium influx (r2 = 0.002, P = 0.78). There was a significant increase in intracellular calcium concentration (P = 0.0008) and in the rate of rise of intracellular calcium levels (P = 0.0009) after reperfusion. CONCLUSION: There was a significant increase in circulating monocyte membrane permeability for calcium and cytosolic calcium concentration following reperfusion in human OLT. This was independent of extracellular calcium concentration. These results are consistent with WBC activation by reperfusion and could be implicated in the systemic reperfusion syndrome seen in OLT in humans.

Adult↗
PubMed1998

Serum CRP and IL-6 levels after trauma. Not predictive of septic complications in 31 patients.

We studied 31 blunt trauma victims, Injury Severity Score (ISS) mean 14 (9-57), for the pattern of release of C-reactive protein (CRP) and cytokine interleukin-6 (IL-6). Blood samples were taken on admission (within 6 hours of injury), as well as at 24 hours, and 3, 5 and 7 days. Serum CRP and IL-6 were measured by ELISA. Subsequent surgical events and sepsis were noted. Serum IL-6 levels on admission were considerably higher (median 135 pg mL-1) than our laboratory reference range (< 5 pg mL-1), slowly returning towards reference values during the study. Serum CRP levels were similar to laboratory normal values on admission (median 8.5 mg L-1 vs 7.5 mg L-1), reaching peak values (median 110 mg L-1) after 3 days. There was a correlation between IL-6 release and ISS but not between CRP and ISS. Patients undergoing surgery showed further increases in IL-6 and CRP levels postoperatively. Of 24 surgical patients, 9 developed postoperative sepsis. In blunt trauma patients, early assessment of the markers CRP or IL-6 were not useful for the diagnosis of sepsis. Levels of CRP following accidental or surgical trauma should be assessed with caution.

Adult↗
PubMed1997

Living related small bowel transplantation: anaesthesia and peri-operative care.

The peri-operative management of the only surviving case, to date, of living-related small bowel transplantation is described. The anaesthetic technique was chosen to optimize hepato-splanchnic blood flow. Peri-operative splanchnic blood flow was measured and alterations in flow with changes in inotropic agents and volume loading monitored. There appears to be a role for the use of dopexamine and aggressive volume loading.

Adult↗
PubMed1997

Effects of desflurane and isoflurane on splanchnic microcirculation during major surgery.

Isoflurane has been considered the agent of choice where preservation of splanchnic blood flow is required. Liver blood flow and the hepatic artery buffer response are maintained better in the presence of isoflurane than with other volatile anaesthetic agents. The effects of desflurane have not been assessed in humans. Therefore, we have compared the effects of isoflurane and desflurane anaesthesia on small bowel and hepatic microcirculatory flow during major surgery using laser Doppler flowmetry in a prospective, randomized, single-blind, crossover study. Patients were allocated randomly to receive desflurane or isoflurane (1 MAC) in oxygen-enriched air. Steady-state jejunal and liver blood flow in segment III were assessed by laser Doppler flowmetry. Volatile anaesthetics were then interchanged, and measurements repeated at steady state. Desflurane anaesthesia at 1 MAC was associated with significantly greater gut blood flow than 1 MAC of isoflurane. These differences could not be explained by systemic haemodynamic differences. The similarity in total hepatic flow between groups implies an intact hepatic artery buffer response with desflurane and isoflurane.

Abdomen↗
PubMed1997

Changes in inflammatory mediators during orthotopic liver transplantation.

Transplantation is associated with an inflammatory rejection response. Graft reperfusion causes typical haemodynamic and biochemical responses. In this study we have investigated the relationship between these haemodynamic responses and changes in circulating inflammatory mediators after graft reperfusion in 10 consecutive patients undergoing orthotopic liver transplantation. After reperfusion, systemic vascular resistance index decreased (P = 0.011) and cardiac index increased (P = 0.038). These characteristic haemodynamic changes of the reperfusion syndrome were accompanied by global increases in cytokine concentrations. Plasma concentrations of leukotrienes decreased, while thromboxane B2 and platelet activating factor remained increased throughout. Reperfusion-mediated changes in inflammatory mediators may account for the haemodynamic disturbance.

Adult↗
PubMed1996

The effect of intrathecal midazolam on post-operative pain.

Intrathecal midazolam for use as a post-operative analgesic when given alone and in conjunction with intrathecal diamorphine was assessed. Fifty-two patients scheduled for elective Caesarean section under spinal anaesthesia were randomly allocated to receive either bupivacaine (B), bupivacaine with diamorphine (BD), bupivacaine with midazolam (BM) or all three (BMD) by intrathecal injection. Post-operatively, no differences in visual analogue score (VAS), sedation or post-operative nausea and vomiting (PONV) could be demonstrated between groups. Patient-controlled analgesia system (PCAS) usage was significantly greater in group B when compared with the other groups. Pruritus was commoner in patients receiving diamorphine (BMD & BD). No side effects attributable to midazolam were identified. Intrathecal midazolam at this dose appears safe and has clinically detectable analgesic properties. The duration of useful analgesia appears to be short-lived.

Analgesia, Patient-Controlled↗
PubMed1996

Mediators of fibrinolysis in orthotopic liver transplantation.

Activation of fibrinolysis remains a clinical problem in orthotopic liver transplantation. We have measured tissue plasminogen activator (t-PA), plasmin and alpha-2-anti-plasmin (alpha 2AP) activities in plasma from 10 patients undergoing elective transplantation. t-PA activity increased during the anhepatic phase and immediately after graft reperfusion (p > 0.001). This increase could not be attributed to t-PA released by the donor liver. Overall transfusion requirements did not relate with either t-PA or alpha 2AP activities individually, but were strongly correlated with the ratio t-PA/ alpha 2AP (p > 0.02). These results suggest that routine prophylactic use of antifibrinolytic agents may be beneficial.

Adult↗
PubMed1995

Cardiac function during orthotopic liver transplantation with venovenous bypass.

We have studied the effect of varying the flow of a venovenous bypass system during orthotopic liver transplantation. During these manipulations, central venous (n = 9) or pulmonary artery occlusion (n = 9) pressures were kept constant. There was no change in right ventricular systolic or diastolic function in either group, suggesting that any conformational change of the ventricle during bypass is not of functional significance. The extrapolated volume loading required to compensate for the absence of bypass is of the order of 3000 ml.

Adult↗
PubMed1994

Haemodynamics of liver reperfusion: comparison of two anaesthetic techniques.

Reperfusion during liver transplantation is associated with cardiovascular instability. We have compared the effects of two anaesthetic techniques on these changes. Twenty-six consecutive patients undergoing elective orthotopic liver transplantation were anaesthetized using either isoflurane or propofol. Haemodynamic profiles were studied before and at specific times after liver graft reperfusion. Systemic vascular resistance decreased at reperfusion in both groups (P < 0.0001), which was accompanied by increased cardiac output which attenuated changes in mean arterial pressure. In the isoflurane group, cardiac output was maintained primarily by improvement in stroke volume, whereas in the propofol group the increase in stroke volume was less marked and cardiac output was maintained by a greater heart rate. The cardiovascular changes were tolerated less well in those patients receiving propofol.

Adult↗
PubMed1994

Reflux during positive pressure ventilation through the laryngeal mask.

Patients undergoing anaesthesia for cataract surgery were anaesthetized and their lungs ventilated by intermittent positive pressure ventilation. In one group, ventilation was facilitated by tracheal intubation and in the other group by laryngeal mask airway (LMA). Reflux of stomach contents into the oesophagus was monitored continuously using an indwelling oesophageal pH electrode. The number of discrete episodes of reflux was higher in the LMA group (P = 0.0178), as was the incidence of reflux at antagonism of neuromuscular block (P = 0.0349).

Anesthesia, General↗
PubMed1992

A study into the incidence of methaemoglobinaemia after 'three-in-one' block with prilocaine.

A 34-year-old female patient developed methaemoglobinaemia following a femoral nerve block using prilocaine. The concentrations of methaemoglobin in the blood of the next eight patients receiving this block were assayed, and found to be significantly increased above baseline concentrations, but very significantly less than the concentration in the patient with symptomatic methaemoglobinaemia. Pulse oximetry was of value in making the diagnosis.

Adult↗