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G Lyons

Publications and source records attributed to G Lyons.

At least 37 records · Page 2Linked to original sources
PubMed2004

In vitro evidence of gender-related heparin resistance.

Coagulability varies among men, women, and pregnant women, along a spectrum where the blood of men is the least and that of pregnant women the most coagulable. The effects of differences in coagulation status on the action of heparin cannot be measured by specific laboratory tests such as aPTT or anti-Factor Xa assay. Thromboelastography which measures whole blood coagulation can assess the effect of heparin against differing backgrounds of coagulation. The aim of this in vitro study was to explore differences in heparin effect between men, women and pregnant women. Fifteen male and female staff volunteers, and 15 pregnant women approaching term, donated venous blood, which was added to four cups in two TEG 5000 analysers. In the cups of the analysers was 0.03 mL of saline control, or heparin 0.4, 0.6 or 1 unit/mL. TEG variables r and k, angle and MA were compared across the groups using two way ANOVA. All subject groups demonstrated a significant heparin effect, which was least in the control group and greatest with 1 unit/mL (P < 0.0001). Across the subject groups, from men to pregnant women, increasing coagulability was seen, with shortening of r and k (P < 0.04), and increasing angle and MA (P < 0.0001). A relationship between gender and heparin was significant for r and k (P < 0.02) but not for angle and MA. This result assists the case against a one-size-fits-all approach to policies on heparinisation.

Adolescent↗
PubMed2004

Supraventricular tachycardia in pregnancy.

We present four cases of supraventricular tachycardia in pregnancy of varied aetiology. Risk factors for the development of supraventricular tachycardia and options for obstetric anaesthetic management, during pregnancy, labour, and at Caesarean section are discussed. We recommend the use of adenosine as first line therapy.

Adult↗
PubMed2003

Preeclampsia complicated by placental abruption, HELLP, coagulopathy and renal failure - further lessons.

We present a case of preeclampsia complicated by HELLP (haemolysis, elevated liver enzymes and low platelets) syndrome and marked coagulopathy. The severity of the coagulopathy and haemolysis made renal failure and pulmonary oedema inevitable. We identified a number of discussion points in this case. These were the delay to appreciate the haemolysis, the severity of the haemolysis and its interaction with the treatment of coagulopathy and the conservative management of pulmonary oedema. At these points there were shortcomings in our management of this complex case that merit further discussion.

Journal Article↗
PubMed2002

Postpartum neurological symptoms following regional blockade: a prospective study with case controls.

We undertook a 12-month prospective study to establish the incidence, nature and significance of postpartum neurological symptoms. To explore the effects of regional blockade, obstetric intervention and neurological examination, women with symptoms after regional blockade were matched with two asymptomatic case controls, one with similar regional blockade and obstetric intervention and another without either regional blockade or obstetric intervention. Twenty-two of 2615 women who had received regional blockade and one of 1376 who had not, presented with postpartum neurological symptoms (incidence 5.8:1000). Presentation with symptoms was associated with regional blockade (P = 0.003) but may reflect reporting bias. Sixty-three women were recruited and examined in a standardised manner. Neurological deficits were identified in all groups. Twelve women were readily diagnosed with obstetric palsies, all of which were associated with vaginal rather than caesarean delivery (P = 0.003). Four of these women had not volunteered symptoms before examination. Six women reported lower sacral dermatome numbness of unknown aetiology but associated with caesarean delivery (P = 0.002). Non-anatomical sensory loss in four of 21 women with symptoms was also noted in 10% of the controls and is likely to be of little clinical significance. Sixteen women who had presented with symptoms completed a 6-month follow-up interview. Thirteen had no symptoms and three had residual sensory symptoms but no functional impairment. These results confirm that postpartum neurological dysfunction is more frequent if specifically sought, and support the clinical impression that significant neurological deficits occur irrespective of the use of regional anaesthesia.

Journal Article↗
PubMed2001

Minimum local analgesic dose of intrathecal bupivacaine in labor and the effect of intrathecal fentanyl.

BACKGROUND: Combining bupivacaine with fentanyl for intrathecal analgesia in labor is well recognized, but dosages commonly used are arbitrarily chosen and may be excessive. This study aimed to determine the median effective dose (ED50) of intrathecal bupivacaine, defined as the minimum local analgesic dose (MLAD), and then use this to assess the effect of different doses of fentanyl. METHODS: In this double-blind, randomized, prospective study, 124 parturients receiving combined spinal epidural analgesia at 2-6-cm cervical dilatation were allocated to one of four groups to receive bupivacaine alone or with 5, 15, or 25 microg fentanyl, using the technique of up-down sequential allocation. Analgesic effectiveness was assessed using 100-mm visual analog pain scores, with less than or equal to 10 mm within 15 min defined as effective. MLAD was calculated using the formula of Dixon and Massey. Pruritus and duration of spinal analgesia were also recorded. RESULTS: Minimum local analgesic dose of intrathecal bupivacaine was 1.99 mg (95% confidence interval, 1.71, 2.27). There were similar significant reductions in MLAD (P < 0.001) for all bupivacaine-fentanyl groups compared with bupivacaine control. There was a dose-dependent increase in both pruritus and duration of spinal analgesia with increasing fentanyl (P < 0.0001). CONCLUSION: Under the conditions of this study, the addition of intrathecal fentanyl 5 microg offers a similar significant bupivacaine dose-sparing effect as 15 and 25 microg. Analgesia in the first stage of labor can be achieved using lower doses of fentanyl, resulting in less pruritus but with a shortening of duration of action.

Adult↗
PubMed2001

Minimum analgesic dose of epidural sufentanil for first-stage labor analgesia: a comparison between spontaneous and prostaglandin-induced labors in nulliparous women.

BACKGROUND: The aim of this prospective, double-blind, sequential allocation study was to compare the effects of spontaneous and prostaglandin-induced labor on the minimum analgesic dose of epidural sufentanil in the first stage of labor. METHODS: Seventy healthy, nulliparous women, at more than 37 weeks' gestation with cervical dilatation from 2 to 4 cm, requesting epidural pain relief in labor were enrolled. The subjects were assigned to two different groups according to whether labor was spontaneous or induced with dinoprostone 0.5 mg. Parturients received 10 ml of the study solution through a lumbar epidural catheter. The initial dose was sufentanil 25 microg, and subsequent doses were determined by the response of the previous patient in the same group using up-down sequential allocation. The analgesic effectiveness was assessed using 100-mm visual analog pain scores. The up-down sequences were analyzed using the method of independent paired reversals and probit regression. RESULTS: The minimum analgesic dose of sufentanil in spontaneous labor was 22.2 microg (95% CI: 19.6, 22.8) and 27.3 microg (95% CI: 23.8, 30.9) in induced labor. The minimum analgesic dose of sufentanil in induced labor was significantly greater (P = 0.0014) than that in spontaneous labor (95% CI difference: 2.9, 9.3) by a factor of 1.3 (95% CI: 1.1, 1.5). CONCLUSION: Prostaglandin induction of labor produces a significantly greater analgesic requirement than does spontaneous labor.

Adult↗
PubMed2001

Advancing health promotion in Australian general practice.

Health promotion activities, while having the potential to prevent disease and decrease the burden of ill health, often play a minor role in the health care offered by general practitioners. There are several identified barriers to the involvement of Australian general practitioners in health promotion. These include structural barriers and barriers within the practice setting, individual practitioner and patient factors, and difficulties in evaluating the outcomes of health promotion activities. This article explores the barriers to the engagement of Australian general practice with health promotion and reviews several recent initiatives that have the potential to increase the health promotion activities of general practitioners. These initiatives act at the level of the individual practitioner, the practice, and in the community. Despite the lack of a coordinated national approach, these strategies form an important development in general practice.

Accreditation↗
PubMed2000

Survivors of childhood cancers: implications for obstetric anaesthesia.

Treatment of many childhood malignancies involves surgery, radiotherapy and chemotherapy. If the child survives, normal physical development can be impaired and abnormalities with anaesthetic implications may be present. We discuss two women with a range of problems who presented for obstetric anaesthesia, having survived childhood malignancies. Common features included anthracycline cardiotoxicity and short stature. Both patients received incremental spinal anaesthesia in order to titrate the dose of local anaesthetic required to produce an adequate block height and to minimize cardiovascular instability.

Adult↗
PubMed2000

Preparation for regional anaesthesia induces changes in thrombelastography.

The effects of crystalloid and colloid infusions on coagulation measured by thrombelastography (TEG) present a confused picture. The influence of environmental factors may explain the disparity between previous studies. We studied two groups of 20 women presenting at term for elective Caesarean section. In the first group, TEG analysis was performed before and after infusion of Gelofusine 500 ml over 15 min. The second group was treated in the same way except that subjects did not receive fluid. We found significant changes in r and k values in both groups, suggesting enhanced coagulation. As hypercoagulable changes were also seen in the group that did not receive fluid preload, the hypothesis that moderate haemodilution causes hypercoagulability must be questioned. The influence of environmental factors can explain differences reported between in vivo and in vitro studies.

Adult↗
PubMed1999

Relative potencies of bupivacaine and ropivacaine for analgesia in labour.

We have used the technique of randomized, double-blind sequential allocation to compare the minimum local analgesic concentrations (MLAC) of epidural bupivacaine and ropivacaine for women in the first stage of labour. The test bolus was 20 ml of local anaesthetic solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of local anaesthetic, according to up-down sequential allocation. Efficacy was assessed using a 100-mm visual analogue pain score (VAPS). The test solution had to achieve a VAPS of 10 mm or less to be judged effective. For bupivacaine, MLAC was 0.093 (95% CI 0.076-0.110)% w/v, and for ropivacaine, 0.156 (95% CI 0.136-0.176)%w/v (P < 0.0001, 95% CI difference 0.036-0.090). The analgesic potency of ropivacaine was 0.60 (0.47-0.75) relative to bupivacaine. Claims for reduced toxicity and motor block must be considered with differences in analgesic potency in mind.

Adult↗
PubMed1999

Morbidity and mortality from obstetric anaesthesia in the 1990s.

As anaesthetic-related maternal mortality reduces in the developed world, alternative indicators of obstetric anaesthetic quality are required. Serious morbidity is difficult to define and quantify, but can be reduced by the provision of effective critical care. Regional anaesthesia, although safer than general anaesthesia, is not without risks. Evidence-based strategies exist to reduce the risks.

Journal Article↗
PubMed1998

Minimum local analgesic concentration of extradural bupivacaine increases with progression of labour.

We have used the technique of double-blind sequential allocation to quantify the minimum local analgesic concentration (MLAC) of extradural bupivacaine for women in early (median cervical dilatation 2 cm) and late (median cervical dilatation 5 cm) labour. The first bolus was 20 ml of the bupivacaine test solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of bupivacaine according to up and down sequential allocation. Efficacy was assessed using a 100-mm visual analogue pain score (VAPS). The test solution had to achieve a VAPS of 10 mm or less to be judged effective. In early labour, the MLAC of bupivacaine was 0.048% w/v (95% confidence intervals (CI) 0.037-0.058% w/v), and 0.140% w/v (95% CI 0.132-0.150% w/v) in the late group. The MLAC of bupivacaine in late labour was greater by a factor of 2.9 (95% CI 2.7-3.2) compared with the MLAC in early labour (P < 0.0001, 95% CI difference 0.08-0.11). We conclude that advancing labour requires an increased concentration of extradural bupivacaine for pain relief.

Adult↗