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PubMed1992

Alternatives to randomization in surgical studies.

The purpose of randomization is to provide unbiased estimates of treatment effects and valid probability statements for hypothesis tests in comparative studies. Difficulties with randomized allocation of patients in surgical studies include: patient selection--due to protocol limitations, possible changes in referral patterns, the need for patient consent, and physician co-operation; disruption of the patient-physician relationship; static protocol not responsive to changes as surgical skill evolves and experience regarding patient selection is acquired; the larger number of patients required causes a longer study and more patients receiving what may be a worse therapy. Moreover, for evaluating a new heart valve, the primary purpose should be estimation rather than comparison with a current device. This can be accomplished faster, in a more generalizable way and with more concern for patient care by using non-randomized comparison groups.

Ethics, Medical↗

PubMed1992

Relationship between the onset of oestrus, the preovulatory surge in luteinizing hormone and ovulation following oestrous synchronization and superovulation of farmed red deer (Cervus elaphus).

The timing of ovulation relative to the onset of oestrus and the preovulatory surge in luteinizing hormone (LH) was studied in red deer following treatments to synchronize oestrus and induce either a monovulatory or superovulatory response. Mature hinds (n = 36) were allocated randomly to two mating groups (n = 16 + 20), with respective treatments staggered by 4 weeks during the 1990 rut (March-April). Each hind was treated with an intravaginal controlled internal drug releasing (CIDR)-type S device for 14 days. Treatments to induce a monovulatory response included CIDR device alone (treatment A; n = 4 + 8) and additional injection of 200 iu pregnant mares' serum gonadotrophin (PMSG) at device removal (treatment B; n = 4 + 4). Treatments to induce a superovulatory response included injections of 200 iu PMSG and 0.5 units ovine follicle-stimulating hormone (FSH) at about time of removal of CIDR devices (treatment C; n = 4 + 4) and further treatment with gonadotrophin-releasing hormone (GnRH) analogue 18 h after removal of CIDR devices (treatment D; n = 4 + 4). The hinds were run with crayon-harnessed stags from insertion of CIDR devices (12 March or 9 April) and blood samples were taken every second day to determine plasma progesterone. Further blood samples were collected for determination of plasma LH and progesterone via indwelling jugular cannulae every 2 h for 72 h from removal of CIDR devices. Hinds were allocated randomly to an initial ovarian examination by laparoscopy at either 16 or 20 h (A and B), or 12 or 16 h (C and D) after the onset of oestrus, with laparoscopy repeated at intervals of 8 h until either ovulation was recorded (A and B), or for four successive occasions (C and D). All hinds received cloprostenol injections 15 days after device removal. A total of 28 hinds (78%) exhibited oestrus and a preovulatory LH surge, with mean (+/- SEM) times to onset of oestrus of 44.6 +/- 1.0 h (A; n = 7), 37.4 +/- 2.0 h (B; n = 7), 16.3 +/- 1.7 h (C; n = 6) or 14.0 +/- 1.7 h (D; n = 8). Failure to exhibit oestrus or LH surge was most prevalent among hinds in treatment A early in the rut.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1990

Double blind comparative study of omeprazole and ranitidine in patients with duodenal or gastric ulcer: a multicentre trial. Cooperative study group.

We studied omeprazole and ranitidine in promoting duodenal ulcer healing in a multicentre trial by comparing the proportion of healed ulcers after two, four, and eight weeks of treatment. Altogether, 194 patients (143 men) were randomly allocated according to a prearranged treatment schedule to either drug and were treated double blind. Each received 40 mg omeprazole in the morning and a ranitidine placebo morning and evening or 150 mg ranitidine morning and evening with an omeprazole placebo in the morning. A total of 188 patients (94 taking omeprazole, 94 taking ranitidine) completed the trial. Sixty four (68%) omeprazole treated and 45 (48%) ranitidine treated patients had healed ulcers at two weeks, 91 (99%) omeprazole treated and 79 (88%) ranitidine treated had healed ulcers by four weeks, and 91 (100%) omeprazole treated and 86 (97%) ranitidine treated patients had healed ulcers by eight weeks. The overall difference in healing rates was significant (p = 0.0008, Mantel-Haenszel test). The differences were significant also at two weeks (20%, 95% confidence interval 5.6 to 34.4, p less than 0.01) and at four weeks (11%, 95% CI 3.7 to 17.3, p less than 0.01), but not at eight weeks (3%, 95% CI -0.5 to + 7.3, p = 0.25), using the chi 2 statistic, the study having a power to detect a 20% difference on 90% of occasions. After two weeks of treatment complete symptom relief was observed in 70 (74%) patients receiving omeprazole and in 58 (62%) receiving ranitidine. Diary cards showed a significantly lower percentage of days with pain in the omeprazole treated group (7.4% v 21.4%, p < 0.02) when assessed over either the first two weeks or over weeks three and four treatment. A total of 144 patients with healed duodenal ulcer were followed up, with no treatment, for six months. At the end of this period 19 (26%) of 74 patients healed with omeprazole and 17 (24%) of 70 patients healed with ranitidine were still in remission. A similar protocol was used for 46 patients (25 men) with gastric ulcer who were randomly allocated to treatment with omeprazole or ranitidine as described above. Forty patients (16 omeprazole, 24 ranitidine) completed trial. Thirteen (81%) omeprazole treated and 14 (58%) ranitidine treated patients had healed ulcers at four weeks; at eight weeks 14 (93%) omeprazole treated and 20 (87%) ranitidine treated patients had healed ulcers. These differences were not significant at four weeks (p = 0.25) or eight weeks (p = 0.96). Twenty seven gastric ulcer patients were followed up for six months and seven (58%) of the 12 omeprazole healed and five (33%) of the 15 ranitidine healed patients were in remission at six months. Unwanted adverse events were trivial except for one fatality in a 67 year old women, who died from bronchopneumonia and myocardial ischaemia while receiving treatment with omeprazole, which was judged to be unrelated to her death.

Aged↗

PubMed1991

Practice randomization and clinical research. The Indiana experience.

Thoughtful preparation of a research laboratory is an early step in designing a program for scientific investigation. The Division of General Internal Medicine at Indiana University has maintained a "laboratory" for outpatient clinical investigation for more than 15 years. In this report, we describe the structure and function of the General Medicine Practice in the Regenstrief Health Center on the campus of the Indiana University School of Medicine in Indianapolis. Specifically, we discuss the ongoing random allocation of subjects, the local resources for data management and tracking of patients' use of clinical services, and how combining this information system into a randomized primary care system has fostered successful ventures in clinical investigation.

Health Services Research↗

PubMed1992

Efficacy of milbemycin oxime against experimentally induced Ancylostoma caninum and Uncinaria stenocephala infections in dogs.

Twenty-eight helminth-naive Beagles, 16 to 26 weeks old, were inoculated with 200 third-stage larvae each of Ancylostoma caninum and Uncinaria stenocephala 5 times at weekly intervals. Dogs were randomly allocated to 4 groups of 7 on the basis of fecal egg counts, and treatments were randomly assigned. Groups 1 and 3 were given milbemycin oxime at a dosage of 500 micrograms/kg of body weight, PO, on day 0 and on days 0 and 30, respectively; groups 2 and 4 were nontreated controls. Fecal egg counts were evaluated before and after treatments. Feces were collected daily for 7 days after the final treatment for recovery of worms passed, and all dogs were euthanatized 7 days after the final treatment for recovery of worms retained. A 65.7% reduction from the pretreatment value for geometric mean hookworm egg count was found 7 days after the first treatment, and a 97.1% reduction 7 days after the second treatment. Although milbemycin oxime had 96.5% and 99.5% controlled efficacy against A caninum after 1 or 2 treatments, respectively, it lacked efficacy against U stenocephala. The geometric mean number of U stenocephala and the total number of hookworms retained after 1 or 2 treatments were not significantly different from the numbers retained by the corresponding control groups.

Ancylostoma↗

PubMed1978

[Therapeutic progress. Critical analysis of controled and non-controled clinical studies].

Methods used in the evaluation of therapeutic results in clinical oncology are criticized on the basis of recent examples of studies including the most-used antitumor agents. The need for random allocation of patients in comparative studies is underlined and the practical, statistical, and ethical limitations on randomization procedures are reviewed.

Ethics, Medical↗

PubMed1977

Hypertension during pregnancy, with and without specific hypotensive treatment. I. Perinatal factors and neonatal morbidity.

In a prospective study, women who were hypertensive before the 28th wk of gestation were randomly allocated into two groups: those who received specific hypotensive therapy (Ht) and those who did not (Hu). The outcome was compared with a random sample of the hospital population (S) ascertained after delivery. In both hypertensive groups there was a higher incidence of clinical signs of possible fetal distress and instrumental delivery. Although there was no difference between the groups in the distribution of birthweight above and below the mean for gestational age, the treated hypertensive group had an excess of infants with relatively smaller head circumferences for their gestational age compared with both the untreated hypertensive group and the hospital sample. Tube-feeding was also more frequent in the treated hypertensive group. In the untreated hypertensive group there were more infants whose neurological status was categorized as questionable or abnormal in the neonatal period, compared with the sample. The different problems encountered by infants in the two hypertensive groups emphasized the need for further study of these babies. Their development during the first year of life will be examined in a subsequent paper.

Female↗

PubMed1990

Serotonin antagonism reduces the adverse symptoms of beta blockade.

Beta-adrenoceptor antagonists (beta blockers) are a well-established first-line treatment for hypertension, but they have been associated with unwanted symptoms including cold extremities, lethargy, and nightmares. Ketanserin is a serotonin S2-receptor antagonist that has previously been shown to reduce blood pressure in hypertensive patients by reducing systemic vascular resistance. Hypertensive patients whose sitting diastolic blood pressure was greater than or equal to 95 mmHg, despite at least 4 weeks therapy with an optimal dose of beta blocker, were selected for the study. The beta-blocker dose remained constant throughout the study, but patients were randomly allocated to receive ketanserin 20 mg twice daily, ketanserin 40 mg twice daily, or bendrofluazide 5 mg each morning plus placebo at night in addition to the beta-blocker therapy. One hundred and forty two patients completed the symptom questionnaire at randomization and after 12 weeks treatment. The treatment groups were well matched for age, sex, weight, and blood pressure. Blood pressure was reduced significantly by all treatments, and there were no between-group differences. Bendrofluazide adversely affected alertness (p less than 0.05) and concentration (p less than 0.01) whereas ketanserin had no significant effect and the ketanserin 20 mg twice daily group had better concentration than the bendrofluazide group (p less than 0.05). Ketanserin treatment reduced the incidence of nightmares (p less than 0.05 for 20 mg twice daily and 40 mg twice daily) and was an improvement over bendrofluazide treatment in this respect (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗

PubMed1979

Randomized clinical trials in the evaluation of surgical innovation.

Randomized clinical trials are widely accepted as the standard for evaluation of therapeutic innovation in many fields of medicine. The three basic components of such trials (concurrent comparison, random allocation, and objective observation) are designed to control four forms of bias (chronology bias, susceptibility bias, compliance bias, and observation bias) that may interfere with the interpretation of the results of a study. Only 2% of the articles evaluating therapeutic maneuvers published in the Journal of Neurosurgery have attempted to use concurrent controls. Only one of 863 such articles met the criteria for a randomized clinical trial. Reasons for underutilization of such trials in neurosurgery are discussed and suggestions for their wider use are offered.

Clinical Trials as Topic↗

PubMed1979

Anticoagulants in the treatment of small cell carcinoma of the bronchus.

The object of this study was to see if the addition of anticoagulants to a regimen of cytotoxic drugs would improve the prognosis in patients with small cell carcinoma of the bronchus. Twenty-four patients were randomly allocated to receive chemotherapy or chemotherapy plus anticoagulants. The median survival in the group receiving the anticoagulants was not improved.

Antineoplastic Agents↗

PubMed1992

High frequency jet ventilation: use of the Bain system for entrainment.

The use of a Bain system to convey anaesthetic gases for entrainment during high frequency jet ventilation (HFJV) was evaluated by examining the effect of varying the fresh gas flow (Vf) on the end-tidal carbon dioxide (PECO2) in 46 ASA physical status I and II patients undergoing extracorporeal shock-wave lithotripsy (ESWL). Anaesthesia was induced with methohexitone (1-2 mg.kg-1), fentanyl (1-1.5 micrograms.kg-1) and vecuronium (0.1 mg.kg-1). After endotracheal intubation with a Mallinckrodt Hi-Lo Jet cuffed endotracheal tube, the patient was immersed in a water bath and HFJV at 150 breaths per minute was instituted with an Acutronic AMS 1000 jet ventilator attached to the side channel of the Hi-Lo tube. A Bain system was attached to the proximal end of the endotracheal tube to provide gases for entrainment. Anaesthesia was maintained with an intravenous infusion of methohexitone (5 mg.kg-1.h-1) and 50% nitrous oxide in oxygen for both the jetted and entrained gases. PECO2 was determined at 5-min intervals by a single-breath technique using a calibrated Engstrom Eliza capnograph. Thirty patients were randomly allocated to receive Vf's of 50 (Group 1), 75 (Group 2) and 100 (Group 3) ml.kg-1.min-1, respectively. A further eight patients (Group 4) received a Vf of 100 ml.kg-1.min-1 for 15 min, 75 ml.kg-1.min-1 for the next 15 min and 50 ml.kg-1.min-1 thereafter. In a further group of eight patients (Group 5), Vf was initially 25 ml.kg-1.min-1 for 10 min and was then switched off for the remainder of the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1979

Psychological rehabilitation after myocardial infarction.

The value of psychological counselling in rehabilitating patients after myocardial infarction was assessed. A total of 143 men who had recently had a myocardial infarction were randomly allocated to either a group receiving intensive rehabilitation or a control group, their outcome being examined after six months. Patients with neurotic, introverted personalities had a poor outcome in the control group but a satisfactory outcome when rehabilitated. Neurotic personalities responded to help, and rehabilitative measures did not increase neurosis. In addition all patients with a negative attitude towards their illness and future had a poor outcome but those with a positive attitude did well. Selection by simple methods of patients who would benefit from psychological rehabilitation seems desirable.

Adult↗

PubMed1979

A comparative trial of two oral cholecystographic contrast media--iocetamic acid (Cholebrin) and iopanoic acid (Telepaque).

A comparative trial was made between two oral cholecystographic agents, iocetamic acid (Cholebrin) and iopanoic acid (Telepaque), Fifty patients were given Cholebrin and another 50 were given Telepaque by random allocation. The cholecystographic qualities of the two contrast media showed no significant difference. It was noted that contrast medium within the bowel at the time of the investigation tended to be homogeneous rather than granular with Cholebrin, and the significance of this is discussed. Gastrointestinal side-effects were common with both contrast media, but there was a significantly lower incidence of diarrhoea with Cholebrin than with Telepaque. Various biochemical parameters of hepatic and renal function were measrued in 40 random patients and showed no clinically significant alteration following ingestion of the contrast media.

Administration, Oral↗

PubMed1992

Intravenous sedation for ocular surgery under local anaesthesia.

Anterior segment ophthalmic surgery is commonly performed under local anaesthesia. In order to improve patient comfort, a variety of sedation techniques has been employed in the past. The object of this study was, firstly, to determine whether continuous intravenous sedation during surgery offered any advantages in patients premedicated with temazepam and metoclopramide, and, secondly, to compare midazolam to propofol for this purpose. Forty nine patients were randomly allocated to receive no intravenous sedation (n = 15), continuous propofol infusion (n = 17), or continuous intravenous midazolam infusion (n = 17) after peribulbar anaesthesia. Each technique provided cardiovascular and respiratory stability and allowed early recovery with minimal postoperative sequelae. Unexpected ocular field movement occurred more commonly in the patients receiving intravenous sedation, although statistical significance was not shown (p = 0.06). Significantly more patients in the intravenous sedation groups reported amnesia (p = 0.03). Patient acceptability was good irrespective of the technique used. This study suggests that continuous sedation using propofol or midazolam is not beneficial and should be avoided in ophthalmic patients who have received a simple premedication.

Aged↗

PubMed1991

Performance evaluation of heat-stressed commercial broilers provided water-cooled floor perches.

A study was conducted to determine whether water-cooled floor perches would be utilized by commercial broilers exposed to a constant hot ambient environment; and subsequently, whether utilization of these perches would improve performance beyond those provided uncooled floor perches. A total of 330 day-old commercial broiler chicks were randomly allocated to six pens (2.44 m2) in an environmentally controlled facility and maintained in a thermoneutral brooding environment for 16 days. Following this period, 240 birds were selected on a body weight basis and randomly assigned to the six pens. A perch constructed from steel pipe (2.44 m length, 5.0 cm diameter) was then placed diagonally on the litter covered floor of each pen. The birds were first exposed to a thermoneutral period (27.7 C), during which time cooling of the perches in three replicate pens was initiated by circulating tap water. The other three experimental pens received ambient perches. Ambient temperature was then raised to 32.6 C for the following 4 wk. The results of the present study showed that utilization of water-cooled perches by broilers was greater (P less than or equal to .01) than ambient perch utilization throughout the 32.6 C period. Average daily gain was greatest (P less than or equal to .01) for broilers exposed to cool perches. Additionally, they consume more feed (P less than or equal to .05), on a daily basis, than those given ambient perches during the heat-stress period. Broilers exposed to water-cooled perches also had a more efficient gain to feed ratio (P less than or equal to .01). At the completion of the study, final body weight and total body weight gain were greater (P less than or equal to .05) for broilers given water-cooled perches compared with those exposed to ambient perches. Total amount of feed consumed and total feed efficiency were only moderately affected (P less than or equal to .10) by perch treatments. These results indicated that water-cooled perches were beneficial in improving broiler performance during periods of high environmental temperatures.

Animals↗

PubMed1990

Postoperative hypoxemia after nonabdominal surgery: a frequent event not caused by nitrous oxide.

We tested whether anesthesia that includes nitrous oxide (N2O) results in the development of intraoperative and postoperative pulmonary complications, including hypoxemia. We also tested whether aging contributes to the development of such complications, particularly when anesthesia includes N2O. We randomly allocated patients having total hip replacements, carotid endarterectomies, or transsphenoidal hypophysectomies (total n = 270) to an anesthetic regimen with and without N2O (stratified within surgical group). A heat-and-moisture exchanger was included in the anesthetic circuit of all patients. Patients were monitored perioperatively and for 1 wk after surgery using intermittent and continuous pulse oximetry to determine oxyhemoglobin saturation. Intraoperatively, mean oxygen (O2) saturations were lower in patients given N2O, particularly older patients. Hypoxemia (O2 saturation less than 86%) developed in five patients receiving N2O and in one receiving O2. This difference was not significant. Administration of N2O did not decrease postoperative O2 saturation, nor did it alter the incidence of postoperative hypoxemia, cough, or sputum production.

Adult↗

PubMed1991

Cognitive function after spinal or general anesthesia for transurethral prostatectomy in elderly men.

Cognitive functions in 53 elderly men who underwent a transurethral prostatectomy were assessed pre-operatively and 4 days and 3 months post-operatively. Thirteen patients had a preference for one particular type of anesthesia, and the remaining 40 were randomly allocated to receive either spinal or general anesthesia. Cognitive function was not different between the groups receiving different types of anesthesia at either time point and did not decrease post-operatively. No pre- or perioperative variable could distinguish the subgroup of patients who had a post-operative decrease of 2 points or more on the Mini-Mental State Examination. No difference in post-operative performance was found in the patient groups with pre-operative Mini-Mental State Examination scores above or under their age-specific norm. It is concluded that neither hospitalization nor the two forms of anesthesia investigated cause a decrease in cognitive function in elderly men.

Aged↗

PubMed1991

Adenosine provokes myocardial ischaemia in patients with ischaemic heart disease without increasing cardiac work.

Intravenous infusion of adenosine in patients with ischaemic heart disease (IHD) has been shown to induce chest pain and ST-depression. The aim of this study was to determine whether such myocardial ischaemia could be due to an increase in myocardial work. Thus patients with stable angina pectoris (n = 8) were randomly allocated to exercise or adenosine infusion, with a 1-h rest period before the second test. The maximal tolerable work load was 120 +/- 13 W, where all patients but one experienced typical angina pectoris. ECG revealed ST-depressions in all patients. The maximal tolerable dose of adenosine was 108 +/- 6 micrograms kg-1 min-1. All patients experienced chest pain typical of habitual angina pectoris, and all but one developed ST-depressions. During exercise there was a gradual and marked increase in the rate pressure product (RPP), in parallel with the development of ST-depression. By contrast, during infusion of adenosine there was only a minor increase in RPP (P = 0.0001). In conclusion, infusion of adenosine provokes signs and symptoms of myocardial ischaemia in patients with IHD with only a minor increase in cardiac work compared to exercise. These results are consistent with the hypothesis of a myocardial steal.

Adenosine↗