Horizontal segregation of mono-layer granules coordinated by vertical motion.

We experimentally investigate the segregation of a binary mixture of spherical beads confined between two horizontal vertically vibrating plates. The two kinds of beads are of equal diameter and mass but have different restitution coefficients. Segregation occurs in particular ranges of vibration amplitude and frequency. We find that the collisions between beads at an angle to the horizontal plane induce an effective horizontal repulsive force. When one or both bead types bounce up and down in synchronization, the effective repulsive force between the two types of beads is likely to be larger than that found within a single bead type, resulting in the mixture segregating. Non-horizontal collisions also play a role in stabilizing the segregation state by transferring the horizontal kinetic energy back into vertical motion.

[The lived experience of secondipara in childbirth].

The purpose of this qualitative study was to explore-the lived experience of secondipara and to understand the coping behavior dealing with these situations during the childbirth period. The researcher selected ten subjects by purposive sampling. During the course of labor, delivery and postpartum, the researcher served as a care-giver and nurse-participant observer. Data were collected by conducting one-hour in-depth interview, 8-24 hours after delivery. The verbal and non-verbal behavior expressed by the secondipara during interview were then recorded in a narrative process-recording. By means of content analysis, the verbal behavior of subjects was systematically analyzed and categorized. The results show that the lived experience of the secondipara can be categorized as follows: (1) sense of uncertainty about childbirth conditions; (2) threat to the sense of body boundary intactness; (3) trapped within bodily gird due to labor pain; (4) on the brink of losing control of body functions; (5) sense of mis-match about childbirth process; (6) achieving life satisfaction; (7) sense of becoming a new self. The coping behaviors expressed by these women can be categorized as follows: (1) trying to confirm and manage their own childbirth conditions; (2) striving to improve the process of labor and delivery; (3) engaging in equipping and maintaining self; (4) sticking it out by self-empowerment; (5) endeavoring to keep a sense of control; (6) establishing knowledge about the health condition of the newborn; (7) reviewing and integrating childbirth experience into self as a secondipara mother. The result of this study can be used as new knowledge and references for nurses in their actual care of women who are becoming mothers a second time.

Omission of nitrous oxide from a propofol-based anesthetic does not affect the recovery of women undergoing outpatient gynecologic surgery.

BACKGROUND: Although nitrous oxide (N2O) is used commonly during anesthesia, clinically relevant advantages-disadvantages of using this agent are not well established in the ambulatory setting. This study in women undergoing ambulatory gynecologic surgery compares outcomes in patients administered total intravenous anesthesia with propofol versus the propofol plus N2O. The primary outcome was the time to home readiness. Secondary outcomes included the incidence of postanesthetic adverse events. METHODS: Women presenting for elective ambulatory termination of pregnancy or gynecologic laparoscopy were induced with an intravenous sleep dose of propofol and fentanyl. After induction, subjects were randomly allocated to maintenance anesthesia with propofol alone or propofol plus 65% N2O. Patients were assessed by a blinded observer in the postanesthetic care unit at 20-min intervals to determine home readiness. Postoperative pain and nausea were measured with visual analog scales. Postoperative analgesics and antiemetics were recorded. The incidence of adverse events occurring after hospital discharge was assessed by a telephone interview 24 h postoperatively. RESULTS: A total of 740 patients received propofol alone, and 750 patients received propofol plus N2O. Mean home readiness times were not significantly different between treatment groups. There were no significant differences between groups in pain scores, nausea scores, analgesia administration, or antiemetic administration before discharge. There were no significant differences in the frequency of adverse events for 24 h after discharge from hospital. CONCLUSIONS: Omission of N2O from a propofol-based anesthetic for ambulatory gynecologic surgery does not affect time to home readiness or the incidence of postoperative adverse events up to 24 h after discharge from hospital. (Key words: Awareness; outpatient surgery; total intravenous anesthesia.)

Evaluation of zolpidem, triazolam, and placebo as hypnotic drugs the night before surgery.

STUDY OBJECTIVE: To compare the hypnotic effects of a bedtime dose of zolpidem, triazolam, and placebo. DESIGN: "Double-blind, randomized, placebo- and active-controlled, parallel-group" trial. SETTING: Six Canadian hospitals. PATIENTS: 357 patients (aged 19 to 71 years) hospitalized the night before a surgical procedure. INTERVENTIONS: At bedtime, each patient received either zolpidem 10 mg, triazolam 0.25 mg, or placebo, and was allowed to sleep for a maximum of 8 hours. MEASUREMENTS: Outcome measures were subjective in nature and included a morning questionnaire, visual analog scales, and observation forms by study personnel. All continuous variables were analyzed by analysis of variance. All categorical data were compared using the Cochran-Mantel-Haenszel (CMH) test, and the percentage of patients asleep was compared using a CMH chi-square analysis. When significant overall treatment effects were observed, pairwise comparisons were undertaken. Compared with the placebo group, the following parameters were significantly (p < 0.001) different in the zolpidem and triazolam groups: sleep latency was shorter, total sleep time was longer, patients fell asleep more easily, and the number of patients awake 2 hours after drug administration was lower. There were no differences between any groups in next-morning somnolence or ability to concentrate. Both drugs were well tolerated, with adverse event incidence rates nearly identical to placebo. CONCLUSIONS: In patients suffering from transient insomnia, a single dose of zolpidem 10 mg was as effective as triazolam 0.25 mg, and both were more effective than placebo and were well tolerated.

Propofol infusion for induction and maintenance of anesthesia in elderly patients: recovery and hemodynamic profiles.

STUDY OBJECTIVE: To evaluate the effect of propofol infusion for both induction and maintenance of anesthesia on hemodynamics and recovery in elderly patients compared with conventional thiopental-isoflurane anesthesia. DESIGN: Randomized, prospective, study. SETTING: Teaching hospital. PATIENTS: 60 nonpremedicated ASA physical status I, II, and III adult elderly patients scheduled to undergo total hip replacement surgery. INTERVENTIONS: Patients received either intravenous propofol infusion at 0.75 mg/kg/min or thiopental bolus 2 to 4 mg/kg for induction, followed by variable-rate propofol infusion up to 0.15 mg/kg/min or isoflurane 0.5% to 1.5% for maintenance of anesthesia. Nitrous oxide and fentanyl supplements were given in all patients. MEASUREMENTS AND MAIN RESULTS: Perioperative hemodynamic changes, patient recovery profile, and myocardial ischemia incidents were assessed in both anesthetic groups. Induction of anesthesia by propofol infusion (1.6 mg/kg) did not produce significant hypotension (-8.3% +/- 5.5%) or bradycardia; these changes were similar to induction by thiopental bolus injection (3.3 mg/kg). Furthermore, increases in blood pressure and heart rate (HR) during endotracheal intubation were limited to 6% following propofol induction compared with 22% for thiopental induction. During maintenance of anesthesia, the decrease in MAP and HR was comparable in both anesthetic groups. Postanesthetic recovery times for patient to achieve wakefulness, mental orientation, and a maximum Aldrete score (10) were significantly faster in the propofol group, by 4 minutes, 6 minutes, and 20 minutes, respectively; however, the time to discharge from the postanesthesia care unit was not different. Holter-monitored perioperative myocardial ischemic events detected in 23% of the patients occurred independent of hemodynamic changes or the type of anesthetic administered. CONCLUSION: Induction of anesthesia by propofol infusion in elderly patients produces greater attenuation of cardiovascular sympathetic response than thiopental bolus induction. Induction and maintenance of anesthesia by propofol infusion results in more rapid recovery in our elderly patients than thiopental isoflurane anesthesia.

Respiratory depression: an adverse outcome during patient controlled analgesia therapy.

Patient-controlled analgesia (PCA) is one of the more popular means of controlling postoperative pain. However, there is very little in the literature concerning the adverse outcome of respiratory depression in PCA. This report is a prospective study of 4,000 patients on PCA postoperatively. Nine of these patients experienced respiratory problems while on PCA. The respiratory depressions were associated with drug interactions, continuous narcotic infusion, nurse- or physician-controlled analgesia and inappropriate use of PCA by patients. This report identified the common precipitating factors in PCA-associated respiratory depression and its prevention.

Comparison of perioperative mental function after general anaesthesia and spinal anaesthesia with intravenous sedation.

This study compared the postoperative mental function in 44 elderly patients following general anaesthesia (GA) or spinal anaesthesia (SA) with sedation for transurethral resection of prostate. The Mini-Mental State (MMS) was done preoperatively and postoperatively at six hours, one day, three days, five days and one month. The geriatric mental status examination was performed preoperatively and one month after the anaesthetic. There was no significant intergroup difference in the MMS score in the preoperative, six hours, one day, three days, five days and 30 days postoperative scores between the GA and SA with sedation groups. A significant intragroup difference between preoperative and postoperative MMS score was detected in the GA group (P less than 0.02) and in the SA group with sedation (P less than 0.03). In the GA group, the significant decrease in MMS score occurred at 6 h postoperatively (P less than 0.002) whereas in the SA group with sedation, MMS score also decreased significantly at 6 h (P less than 0.005). In conclusion, there was no significant difference in perioperative mental function between the general and spinal anaesthetic groups when supplemental IV sedation was given. In both groups, perioperative mental function decreased significantly at 6 h postoperatively.

Hyperinsulinism associated with primary renal cell carcinoma.

A case is reported of a patient with symptomatic hyperinsulinism associated initially with a renal cell carcinoma and then later, with secondary deposits from the same tumor. Evidence points to a strong possibility of renal tumor involvement in the production of insulin hypersecretion.

Squamous cell carcinoma of the pinna.

A number of cases of squamous carcinoma of the pinna were examined. The rate and pattern of metastases were established and a review of the histology carried out. No histological parameters could be identified at the initial resection that were useful in predicting the likelihood of metastases. The importance of adequate initial surgery is emphasised.