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Biomedical subjects

H Owen

Publications and source records attributed to H Owen.

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

Lack of efficacy of propofol in the treatment of early postoperative nausea and vomiting.

The anti-nauseant efficacy of low-dose propofol was investigated in a blinded, randomized trial. Patients who complained of nausea and/or vomiting following laparoscopic gynaecological surgery and who requested antiemetic were randomly assigned to receive placebo, propofol 3 mg, propofol 9 mg or propofol 27 mg by intravenous injection. Nausea, vomiting and sedation were recorded by a blinded observer for 90 minutes following administration of the test drug, prior to discharge, and 24 hours following surgery. Rescue antiemetic (droperidol 1.0 mg i.v.) was available from 10 minutes after administration of test drug. Propofol failed to reduce nausea scores and did not reduce the incidence of vomiting. Numbers of patients receiving rescue antiemetic were similar in the four treatment groups. In the first 10 minutes following test drug administration, sedation scores were increased by propofol in a dose-related manner. We conclude that, in the dose range studied, propofol is ineffective for the treatment of nausea and vomiting occurring soon after laparoscopic gynaecological surgery.

Adult↗
PubMed1998

Dioxin perturbs, in a dose- and time-dependent fashion, steroid secretion, and induces apoptosis of human luteinized granulosa cells.

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) is the most toxic congener of a large class of environmental pollutants. Several studies have shown that TCDD exposure reduced fecundity and ovulatory rate in rats and increased the incidence of endometriosis in monkeys. Recent work suggests that TCDD's endocrine-disrupting effects are, at least in part, caused by a direct action at the ovary. Although the factors involved in TCDD-induced toxicity are still under investigation, several studies have shown that TCDD induces programmed cell death, or apoptosis, in various tissues and may act in a similar fashion in the ovary. In the present study, we set out to evaluate the in vitro effects of TCDD on steroid secretion, specifically estradiol-17beta (E2) and progesterone, by human luteinized granulosa cells (LGC), and to further determine whether TCDD is capable of inducing apoptosis in this cell type. Human LGC were obtained from women participating in an in vitro fertilization program. Medium, with or without three different concentrations of TCDD and substrates [androstenedione (A4) or pregnenolone], was added to each culture. The media were collected at 4, 8, 12, 24, 36, and 48 h and were assayed by RIA. At 24 and 48 h, the LGC were fixed for assessment of DNA fragmentation via an in situ immunofluorescence technique. Transmission electron microscopy was also performed on LGC after 24 and 48 h with TCDD. TCDD, at all concentrations tested (3.1 pM, 3.1 nM, and 3.1 microM), significantly reduced E2 accumulation in the media at 8, 12, and 24 h, compared with controls. At 36 and 48 h, TCDD treatment (at 3.1 microM) caused a significant increase in E2, compared with controls. The effect of TCDD on E2 was abolished with the addition of A4. TCDD treatment did not alter progesterone accumulation. Apoptosis increased at 24 h with 3.1 microM TCDD, with no apparent effect at 3.1 nM. By 48 h, however, TCDD increased apoptosis in a dose-dependent manner. Transmission electron microscopy showed ultrastructural differences in LGC with 3.1 microM TCDD at 24 and 48 h. Collectively, the results of the present study suggest that TCDD perturbs E2 secretion by depletion of A4 precursor and increases apoptotic cell death of human LGC in a dose- and time-dependent fashion.

Apoptosis↗
PubMed1997

Identification of movement artefact by the Nellcor N-200 and N-3000 pulse oximeters.

OBJECTIVES: The Nellcor N-3000 pulse oximeter is designed to be able to identify signal artefact related to movement of the body part to which the probe is attached. It may therefore provide a reliable means of monitoring arterial oxyhemoglobin saturation (SpO2) in awake, moving patients. This study compared the Nellcor N-3000 and N-200 pulse oximeters in terms of their ability to identify readings associated with movement, in a group of volunteers making standardized movements. METHODS: Thirty-six volunteers were studied. Volunteers breathed room air throughout the study. SpO2 of each volunteer was monitored by both a Nellcor N-200 and a Nellcor N-3000 simultaneously on both hands. Volunteers made a series of five standardized movements, each lasting one minute, with each hand during the monitoring session, while SpO2 and oximeter status were recorded from all four oximeters. The mean SpO2 reading was calculated during each movement. SpO2 readings which the oximeter identified as being associated with movement, pulse search not locked, sensor not attached, or break in communications were excluded from analysis. RESULTS: The N-3000 rejected from 17 to 78% of readings taken during movement, compared to 0 to 2% with the N-200. Although the remaining readings of both types of oximeters were subject to some movement artefact, which led to spuriously low SpO2, this was significantly less with the N-3000. CONCLUSIONS: The Nellcor N-3000 pulse oximeter is able, to some extent, to identify movement artefact. It should offer an advantage over the N-200 when monitoring moving patients.

Adolescent↗
PubMed1997

Morphine patient-controlled analgesia is superior to meperidine patient-controlled analgesia for postoperative pain.

The choice between morphine and meperidine for postoperative pain is usually based on the preference of the prescriber, as few objective comparative data are available. This blind, randomized study compared the efficacy and side effects of morphine and meperidine administered by patient-controlled analgesia (PCA) for postoperative pain. One hundred two consenting patients scheduled for major abdominal surgery were randomly assigned to receive PCA with morphine (0.75, 1.0, or 1.5 mg bolus dose size) or meperidine (9, 12, or 18 mg) for pain control. Postoperative assessments included pain at rest and on sitting, nausea, unusual dreams, the Multiple Affect Adjective Check List (a measure of mood), and the trailmaking tests A and B (measures of ability to concentrate). Pain on sitting (P = 0.037) but not pain at rest (P = 0.8) was significantly less in patients receiving morphine. Meperidine use was associated with poorer performance in the trailmaking tests and a greater incidence of dryness of the mouth. Severity of nausea, mood, and incidence of unusual dreams did not differ significantly between drugs. We conclude that meperidine should be reserved for those patients in whom morphine is judged inappropriate.

Abdomen↗
PubMed1996

Sustained-release ibuprofen as an adjunct to morphine patient-controlled analgesia.

Previous studies have demonstrated reduced postoperative morphine requirements and/or improved pain relief when nonsteroidal antiinflammatory drugs are administered in conjunction with patient-controlled analgesia (PCA). This double-blind study aimed to determine whether these effects could be obtained with a sustained-release ibuprofen formulation (Brufen Retard) given preoperatively, obviating the need for oral administration during the early postoperative period. We aimed also to determine whether the anticipated reduction in morphine requirements was associated with reduced opioid side effects. One hundred fifteen patients scheduled for lower abdominal gynecological surgery were randomly assigned to receive either sustained-release ibuprofen, 2 x 800 mg (n = 57), or placebo (n = 58) preoperatively and again 24 h after the first dose. Arterial oxyhemoglobin saturation (Spo2) was monitored preoperatively and for 24 h postoperatively. Patients were assessed every 4 h up to 24 h postoperatively. Those receiving ibuprofen reported significantly less pain at rest (P = 0.023) and less pain on movement, although the latter was not statistically significant (P = 0.051). Patients' opinions of the efficacy of their pain-relieving medication (P < 0.001) and quality of sleep (P = 0.036) favored ibuprofen. Morphine consumption was slightly but not significantly lower in the ibuprofen group (32 vs 38 mg/24 h, P = 0.096). Spo2 (P = 0.54), level of consciousness (P = 0.65), and number of antiemetic administrations (P = 0.15) did not differ significantly between groups. These results demonstrate improved efficacy with no increase in side effects when sustained-release ibuprofen is used as an adjunct to morphine PCA.

Adolescent↗
PubMed1996

A comparison of variable-dose patient-controlled analgesia with fixed-dose patient-controlled analgesia.

We examined the effect on the quality of analgesia and side effects of increasing the patient control component of morphine patient-controlled analgesia (PCA) by offering the patient a choice of bolus dose sizes. Using a three-button hand piece, patients could choose between 0.5-, 1.0-, and 1.5-mg boluses of morphine (variable-dose PCA, VDPCA). Successful demands were delivered by a modified Graseby 3400 Anaesthesia Pump controlled by a Toshiba T1900 computer. This system was compared with conventional fixed-dose PCA (FDPCA) (1.0 mg of morphine) delivered by a Graseby 3300 PCA Pump. Both treatment groups had a 5-min lockout interval. Sixty patients were randomly assigned to receive either VDPCA or FDPCA after major abdominal gynecological surgery or hip or knee arthroplasty. Treatment groups did not differ in their duration of PCA therapy, total morphine consumption, or time spent with mild or severe oxyhemoglobin desaturation. There were no differences in their ease of controlling pain, satisfaction with pain control, experience of pain on movement, quality of sleep, severity of nausea, or incidence of vomiting. Although the more complex VDPCA technique provides adequate postoperative analgesia, it does not offer any advantage over conventional FDPCA.

Adult↗
PubMed1995

Development of tolerance to antinociceptive effects of an intrathecal morphine/clonidine combination in rats.

Previous animal studies have shown the antinociceptive effects of intrathecal clonidine and intrathecal morphine to be synergistic. This study investigated the intrathecal administration of multiple doses of this drug combination to examine the rate of development of tolerance and to determine whether there was any toxic effect on the spinal cord. Rats with indwelling intrathecal catheters were given saline, morphine (2.5-7.5 micrograms), clonidine (17.5 micrograms), or clonidine (17.5 micrograms) plus morphine (1 microgram) intrathecally twice daily for 4 1/2 days (total of 9 doses). Hot plate and tail flick tests were conducted after the first, fifth and ninth doses. After the ninth dose animals were killed and their spinal cords were removed for histological examination. Tolerance developed to the antinociceptive effects of the drug combination, but at a slower rate than to morphine alone. No evidence of toxicity or injury to the spinal cord was observed other than changes which could be ascribed to the presence of the catheter.

Animals↗
PubMed1995

Variable-dose patient-controlled analgesia. A preliminary report.

One size of patient-controlled analgesia demand dose does not suit all patients after surgery. We have constructed a new patient-controlled analgesia (variable-dose patient-controlled analgesia) in which patients have a choice of demand dose sizes. In an initial trial, patients could choose between 0.5, 1.0 or 1.5 mg morphine. Patients readily understood the system and were all 'satisfied' (n = 1) or 'very satisfied' (n = 9) with the system. Only two patients sought 'complete relief' from pain, most reported seeking 'moderate relief'. All patients obtained a 'lot of relief' or 'complete relief' with this patient-controlled analgesia system. This preliminary experience suggests that variable dose patient-controlled analgesia warrants further investigation and comparison with conventional patient-controlled analgesia.

Analgesia, Patient-Controlled↗
PubMed1995

Evaluation of the influence of movement on saturation readings from pulse oximeters.

This study aimed to develop a protocol for assessing the influence of movement on oxyhaemoglobin saturation readings from pulse oximeters. Thirty-six volunteers took part in the study. In each volunteer, each hand was monitored by both a Nellcor N200 oximeter using a disposable probe and by a Datex Satlite DS103 oximeter using a clip-on finger probe. Volunteers made five standardised movements during which output was recorded from all four oximeters. All movements were associated with apparent decreases in oxyhaemoglobin saturation which were statistically significant for two movements with the Nellcor equipment and for four movements with the Datex equipment. Movement was associated with increases in the magnitude of pulse amplitude, but this was not quantitatively associated with magnitude of artefactual changes in saturation. Use of this standardised movement protocol allows quantification of movement artefact from pulse oximeters and should facilitate the development of equipment less affected by movement.

Adolescent↗
PubMed1995

The introduction of patient-controlled analgesia into an isolated rural hospital.

This study investigated the feasibility of using patient-controlled analgesia (PCA) effectively in a small 70 bed isolated rural hospital. The first 50 patients to use a Bard PCA 1, in the Port Lincoln Hospital, South Australia, were studied. The patients consumed morphine at a mean rate of 1.24 mg/h and used PCA for a mean of 48 h. Thirty-eight per cent of patients required treatment for nausea and other complications which is similar to the rate of those in other published series. Visual analogue pain scores showed excellent pain control, generally without evidence of oversedation; however, there was one episode of respiratory depression. Seventy-eight per cent of patients reported that their pain was relieved most or all of the time. The study demonstrated that a PCA service provided by nursing staff, the GP anaesthetist and rural surgeons is feasible in an isolated rural hospital.

Adult↗
PubMed1995

A double-blind randomized controlled trial of ginger for the prevention of postoperative nausea and vomiting.

The efficacy of ginger for the prevention of postoperative nausea and vomiting was studied in a double-blind, randomized, controlled trial in 108 ASA 1 or 2 patients undergoing gynaecological laparoscopic surgery under general anaesthesia. Patients received oral placebo, ginger BP 0.5g or ginger BP 1.0g, all with oral diazepam premedication, one hour prior to surgery. Patients were assessed at three hours postoperatively. The incidence of nausea and vomiting increased slightly but nonsignificantly with increasing dose of ginger. The incidence of moderate or severe nausea was 22, 33 and 36%, while the incidence of vomiting was 17, 14 and 31% in groups receiving 0, 0.5 and 1.0g ginger, respectively (odds ratio per 0.5g ginger 1.39 for nausea and 1.55 for vomiting). These results were essentially unchanged when adjustment was made for concomitant risk factors. We conclude that ginger BP in doses of 0.5 or 1.0 gram is ineffective in reducing the incidence of postoperative nausea and vomiting.

Adjuvants, Anesthesia↗
PubMed1995

The effect of oral cisapride premedication on fasting gastric volumes.

The aim of this study was to determine whether fasting gastric volumes could be reduced by preoperative administration of cisapride. One hundred and twenty-one patients undergoing elective general anaesthesia were randomly allocated to receive either cisapride 20 mg plus diazepam 10 mg or placebo tablets plus diazepam 10 mg, two hours prior to induction. Immediately following induction blind gastric aspiration was performed using a 16Fr multiorificed orogastric tube. Gastric volume, pH, and cisapride blood concentration were measured at this time. Gastric volumes were significantly smaller in the cisapride group, 20.5 (SD 22.2) ml compared to placebo 28.2 (SD 26.0) ml but there was no significant difference with respect to pH. Some patients in both groups had large gastric volumes despite fasting. No significant adverse effects were noted with cisapride.

Adjuvants, Anesthesia↗
PubMed1994

A system for standardized evaluation of patient-controlled analgesia devices: design, construction, and engineering aspects.

OBJECTIVE: Our objective was to design, construct, and assess an automated system to perform standardized evaluation of patient-controlled analgesia (PCA) devices. METHODS: We developed a computer-controlled test station. The computer activates the PCA device under test through a purpose-built serial interface device. The dose delivered is weighed on an electronic balance; then, at a predetermined interval, the computer interrogates the balance via the serial interface device to determine the weight gain. A robotic digit simulates patient button presses for four commonly used demand mechanisms. Software programs were written to test three types of patient-demand profile. RESULTS: The automated system is sufficiently accurate for evaluating PCA devices and has been successfully used to perform and evaluate several thousand demands on six different models of PCA device. CONCLUSIONS: The test station has proved to be simple to use and extremely reliable, and has enabled the successful evaluation of several types of PCA device.

Analgesia, Patient-Controlled↗
PubMed1994

Changes in oxygen saturation in the 72 hours after hip surgery: the effect of oxygen therapy.

The aim of this study was to investigate changes in oxygen saturation (SpO2) occurring during the three days following hip surgery in patients in this hospital and to determine to what extent SpO2 might be improved by oxygen therapy for 24 or 72 hours. Eighty-three patients (aged 43-96 years) scheduled for elective total hip replacement or emergency surgery for hip fractures were studied. Forty-four patients had 24 hour postoperative oxygen prescribed by their anaesthetist or surgeon; we randomized these to either continue oxygen for a total of three days (Group 1) or to discontinue oxygen after Day 1 (Group 2). Patients not prescribed oxygen by the surgeon or anaesthetist (n = 39) were randomly assigned either to receive oxygen for three days (Group 3) or not to receive oxygen (Group 4). Oxygen was administered through nasal cannulae at a flow of 2 l.min-1. SpO2 was measured every 10 seconds for three days and stored on computer disc. Percentage of time spent with SpO2 below 90% was used as an index of desaturation. Patients receiving oxygen had significantly improved SpO2. In patients not receiving oxygen, desaturation was most severe on Days 1 and 2, improving somewhat on Day 3. On Day 2 desaturation was similar in Groups 2 and 4. When oxygen was not being administered males were significantly more desaturated than females. Our investigations indicate that following hip surgery poor saturation continues for at least two days and can be improved by oxygen therapy.

Adult↗
PubMed1993

Career guidance during nurse training: findings from an exploratory study.

This research into the career guidance experiences of nurses during their training was undertaken as an exploratory study upon which a series of larger studies will subsequently be based. Additionally, it contributed to a national cohort study of the careers of newly qualified registered general nurses. One hundred and twelve nurses were involved in the development and testing of questions for a postal questionnaire to be used in the cohort study of careers. Some problems encountered when investigating career guidance by questionnaire are described, in the light of which a revised research design is proposed and the career guidance experiences of 31 nurses presented. Twenty-one aspects of guidance were investigated, covering information and advice about applying for first post, post-basic courses and longer-term plans.

Career Choice↗
PubMed1993

The effect of fentanyl administered epidurally by patient-controlled analgesia, continuous infusion, or a combined technique of oxyhaemoglobin saturation after abdominal surgery.

The aims of this study were to determine the effect of three different modes of epidural administration of fentanyl on oxyhaemoglobin saturation and pain control. Forty-three patients undergoing elective abdominal surgery were randomly allocated to the following groups: (1) continuous infusion of fentanyl at a rate of 50 micrograms.h-1 with additional epidural boluses (25 micrograms) as required; (2) patient-controlled analgesia using a 25 microgram epidural bolus of fentanyl with a 15 min lock-out period; (3) a combination of patient-controlled analgesia and continuous infusion. Oxyhaemoglobin saturation was measured by continuous computerised pulse oximetry for 48 h after operation together with pain and sedation scores. In the first 24 h after surgery patients in the continuous infusion group spent a significantly greater proportion of time below oxygen saturations of 94% and 85% than those in the other two groups. On day 2 all oxygen saturation measurements were worse than during day 1, but differences between groups were not significant. Those patients receiving patient-controlled analgesia required significantly less fentanyl than patients in either of the other groups (p < 0.05). However, the mean pain and sedation scores did not differ significantly between the three treatment groups. There was no association between total fentanyl dose and oxygen saturation values. Overall, self-administered fentanyl appeared to cause less oxyhaemoglobin desaturation than nurse-administered analgesia without any loss of analgesic effect.

Adolescent↗