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Biomedical subjects

A Holdcroft

Publications and source records attributed to A Holdcroft.

At least 37 records · Page 2Linked to original sources
PubMed1999

Arterial to inspired partial pressure ratio of halothane, isoflurane, sevoflurane and desflurane in rats.

The inspired partial pressure of an anaesthetic is often used as an index of arterial partial pressure in small animal experiments. We have investigated the influence of anaesthetic solubility on the ratio of arterial to inspired partial pressure in 24 rats, allocated randomly to receive halothane, isoflurane or desflurane at four different inspired concentrations. The arterial partial pressure of the volatile agent was measured by two-stage headspace analysis using a gas chromatograph calibrated with the same gas used to calibrate the Datex Capnomac that measured the inspired concentration. Mean values of arterial to inspired ratio at the lowest concentrations were 0.60 (95% confidence intervals 0.50, 0.71) for 0.8% halothane, 0.54 (0.38, 0.69) for 0.8% isoflurane, 0.72 (0.59, 0.86) for 1.5% sevoflurane and 0.71 (0.54, 0.87) for 4% desflurane. Analysis of variance showed a significant effect of anaesthetic agent (P = 0.008) on the arterial to inspired ratio. Thus volatile anaesthetic agents do not demonstrate a fixed arterial to inspired ratio in rats.

Anesthetics, Inhalation↗
PubMed1998

The long-term effects of analgesia in labour.

Women frequently use a mixture of analgesics to gain relief from the distress of childbirth and antenatally require information on their effectiveness and side-effects. One such example would be the reported long-term neonatal behavioural changes following systemic opioids such as pethidine. The most frequently reported maternal effects of epidural or spinal analgesia are prolonged symptoms of headache, backache and neurological sequelae. Large retrospective studies of postpartum symptomatology have focused on correlations with regional nerve blockade rather than on other more commonly used analgesics. Post-dural puncture headache is a recognized long-term complication of epidural nerve blockade. However, prospective studies have not confirmed any causal relationship between epidural analgesia and backache and neurological complications are five times more common after childbirth itself than after regional nerve blockade. Postpartum symptomatology describes significant morbidity in the community but its relationship to analgesia in labour is still to be proved.

Analgesia, Obstetrical↗
PubMed1997

Heat retention using passive systems during anaesthesia: comparison of two plastic wraps, one with reflective properties.

Hypothermia during prolonged surgery may be prevented by active and passive warming methods. We have compared randomly two types of occlusive body wraps in groups of 20 patients. One wrap had additional reflective properties which, by reducing radiative in addition to convective and evaporative heat loss, was expected to improve heat conservation. Patients were studied during hepatopancreatobiliary surgery and both groups were similar in characteristics. Skin and core body temperatures increased and core temperature exceeded 37 degrees C in 40% of patients in both groups. This continuous increase in temperature was unexpected and the observed heat gain may have been stimulated endogenously by the type of surgery rather than that supplied externally. Overall, mean hourly heat gain was similar in both groups: 71 (SD 28) kJ h-1 in the reflective group and 67 (33) kJ h-1 in the other group.

Adult↗
PubMed1997

Pain relief with oral cannabinoids in familial Mediterranean fever.

Cannabinoids have analgesic and, possibly, anti-inflammatory properties but their clinical use has been restricted by legislation. This is the first United Kingdom report of the controlled use of a standardised pharmaceutical preparation of cannabinoids in capsular form. The therapy was assessed in a patient with familial Mediterranean fever, who presented with chronic relapsing pain and inflammation of gastrointestinal origin. After determining a suitable analgesic dosage, a double-blind placebo-controlled cross-over trial was conducted using 50 mg tetrahydrocannabinol daily in five doses in the active weeks and measuring effects on parameters of inflammation and pain. Although no anti-inflammatory effects of tetrahydrocannabinol were detected during the trial, a highly significant reduction (p < 0.001) in additional analgesic requirements was achieved. Future study designs can now incorporate prescribable forms of cannabinoids but the choice of previous cannabis users only as patients has clinical limitations. Cannabis naive patients would tolerate controlled investigations but may generate medicolegal problems.

Administration, Oral↗
PubMed1996

Estrous cycle phase variations in visceromotor and cardiovascular responses to colonic distension in the anesthetized rat.

Visceromotor and cardiovascular responses to colonic distension were measured in female rats, anesthetized with halothane in oxygen, in the proestrus, estrus, metestrus and diestrus phases of the estrous cycle. Ten rats were studied in each group and responses were measured at 5-min intervals for 60 min. A mixed model analysis of variance showed that there was no real change in either the visceral or cardiovascular response with time. There was a highly significant difference in visceromotor responses between the phases of the estrous cycle (P < 0.001). During the phase of proestrus the balloon pressure at which a response was triggered was much lower, with a mean value (95% confidence interval) of 18.7 (16.1, 21.8) mmHg, than the other phases with mean values (95% confidence interval) of 31.9 (27.4, 37.2) mmHg for estrus, 28.1 (24.2, 32.8) mmHg for metestrus, and 31.1 (26.7, 36.3) mmHg for diestrus. The mean arterial blood pressure increased in all groups (range 3.2, 5.4%) as a response to the stimulus, but there was no associated heart rate variability and no significant differences in cardiovascular changes between the groups (P = 0.6). The visceromotor responses measured during the phase of proestrus occurred at a significantly lower threshold than in the other phases of estrous.

Anesthesia↗
PubMed1996

Critically ill parturient women and admission to intensive care: a 5-year review.

Thirty-nine parturient women were admitted to a general intensive care unit (ICU) from April 1989 to March 1994 and of these four were readmitted (total 43 admissions). Twelve women were admitted to the obstetric unit from peripheral hospitals in different regions, but no requirement for intensive care was perceived on referral. Six women were transfered directly into the intensive care unit from different hospitals in the region. The incidence of obstetric patients requiring ICU admission, excluding direct transfers, was 0.64%. The majority (85%) were postpartum, and 64% were primiparous. Morbidity was caused primarily by hypertensive disorders (33%) and haemorrhage (33%). The remainder included medical disorders (21%)[ sepsis (13%) and surgical problems (5%). Associated major complications were acute renal failure, coagulopathies and adult respiratory distress syndrome. A multidisciplinary approach to management is practised and specialist interventions included haemofiltration and haemodialysis (18%) and radiological arterial embolisation (10%). Ventilatory and inotropic support were given in 38% and 41% of patients respectively. Only one patient died on the intensive care unit, this was from multiorgan failure secondary to sepsis.

Journal Article↗
PubMed1995

Post partum magnetic resonance imaging: lumbar tissue changes are unrelated to epidural analgesia or mode of delivery.

Thirty five women consented post partum to daily lumbar back pain assessments and magnetic resonance imaging (MRI) (0.15 Tesla) within 48 hours of delivery using a T(1) weighted spin echo and a fat suppression sequence (STIR) to identify tissue water. Nine women (26%) had lumbar disc abnormalities on MRI scan. Variable degrees of soft tissue changes in the lumbar region were observed using the STIR sequence in all patients after delivery. Eight women (23%) had mild, 15 (43%) moderate, and 12 (34%) severe changes with an average of 5 segments involved. These changes were reversible and related neither to the mode of delivery, nor to the trauma of epidural cannulation.

Journal Article↗
PubMed1995

Neurological complications associated with pregnancy.

Prospective multidisciplinary audit from both hospital and community has identified neurological complications persisting for more than 6 weeks in association with pregnancy and delivery. They occurred at a frequency of 1 in 2530 deliveries in the North West Thames Region. Extradural analgesia was considered contributory to a neurological disorder in one of 13,007 patients. The woman had prolonged paraesthesiae along a nerve root. The types of sensory, motor and sympathetic neurological problems presented ranged from transient problems to more serious disorders resulting in death in one case. Seven of 19 patients had a continuing neurological disability for more than 1 yr. Although obstetrics may be associated with lumbar and sacral neurological disorders, problems occurred with the same frequency in the upper as in the lower half of the body. Significant morbidity is not being recognized in hospitals where women are being delivered and it is within the community that these disorders are recognized. This has implications for training, audit and risk assessment.

Adult↗
PubMed1995

Hereditary angioneurotic oedema: current management in pregnancy.

A 20-year-old primiparous woman, with a history of type 1 hereditary angioneurotic oedema, presented for induction of labour. She was hirsute, obese and presented technical difficulties for both general and epidural/spinal anaesthesia. Her management included prophylactic C1 esterase inhibitors and epidural analgesia for pain relief. A spontaneous vaginal delivery was achieved and no adverse complications occurred. Five days after delivery she had abdominal pain which was investigated and resolved spontaneously. The management of this condition is discussed.

Adult↗
PubMed1995

Factors associated with mothers selecting general anesthesia for lower segment caesarean section.

The objective of the study was to investigate the sociodemographic and psychological factors which are associated with choice or refusal of regional anesthesia for lower segment Caesarean section. A semi-structured questionnaire was administered preoperatively to consecutive women presenting for elective operation at two hospital sites in the same health authority. The questionnaires were administered to 39 pregnant women by two anesthetists, one at each site. Sociodemographic and past and present obstetric and anesthetic details were obtained. The Hospital Anxiety and Depression scale and the FEAR questionnaire were used with an additional visual analog scale to assess fearfulness associated with the proposed operation. A 'panic checklist' of ten items was also constructed to identify procedures associated with feelings of panic. Ten women requested general anesthesia. These women had a similar level of anxiety to the others, but were significantly more depressed, had had more pregnancies overall and more without live babies. There were also more aspects of the procedure at which they thought they might panic. Women who have suffered the loss of a conception with its associated grief and often obstetric intervention are more reluctant to be conscious during an operative delivery for a subsequent baby. Preventive measures should be considered at the time of fetal loss to avoid this. However, preoperatively a simple visual analog scale for fearfulness would identify these women so that any unresolved fears could receive full psychological assessment.

Adaptation, Psychological↗