Pathways through psychiatric care: the experience of psychiatric patients

The aim of this project was to identify the pathway through psychiatric care beyond the point of first admission. This was carried out from the point of view of users, considering the pathway as a set of subjective experiences. Fifty interviews were conducted with people undergoing psychiatric care in a range of service settings, using a semi-structured interview schedule. Although the research was initially conceptualised in terms of pathways, the routes followed by patients proved to be too diffuse to be charted. Some patient careers were both prolonged and erratic. Patients do not follow a definite pathway; rather, they move through a set of complex stages which are often unclear. If respondents lack a subjective sense of a pathway, they feel, at least in part, that it is because they do not know what is happening.     

Reduction of Isoflurane Minimal Alveolar Concentration by Remifentanil

Background: Remifentanil is a new micro-specific opioid receptor agonist currently under investigation. The interaction between opioids and volatile anesthetics is complex. Defining this interaction provides a basis for more rational dosing schemes when such combinations are used for anesthesia and allows the anesthetic potency of remifentanil relative to other opioids to be determined.

Methods: Two centers enrolled a total of 220 patients. Patients were randomized to receive a target concentration of remifentanil via a computer-assisted continuous infusion device of either 0.0, 0.5, 1.0, 1.5, 2.0, 4.0, 8.0, 16.0, and 32.0 ng/ml initiated before the administration of isoflurane. Patients were also stratified by age groups 18-30, 31-55, and 56-65 yr. After induction of anesthesia with isoflurane the initial patient in each dose group was assigned an age-adjusted isoflurane concentration. The isoflurane concentration for each subsequent patient was adjusted according to the up/down technique until a minimum of 12 patients were enrolled in each group. Arterial blood samples for remifentanil whole blood concentrations were obtained. The patient was observed for purposeful movement for up to 1 min after skin incision. The minimum alveolar concentration (MAC) of isoflurane (0 ng/ml remifentanil group) and MAC reduction of isoflurane by remifentanil were determined.

Results: The MAC of isoflurane alone was 1.3%. Remifentanil caused an exponential reduction in the MAC of isoflurane with 1.37 ng/ml remifentanil resulting in a 50% MAC reduction, 4 ng/ml remifentanil a 77% reduction and 32 ng/ml a 91% reduction of isoflurane MAC.     

The peripheral pulse wave: Information overlooked

Although the waveform derived from a peripheral pulse monitor or pulse oximeter may resemble an arterialpressure waveform, it is in fact a visualization of blood volume change in transilluminated tissue caused by passage of blood: an indication of perfusion or bloodflow. Most currently available pulse oximeters indicate this flow, but few display it in usable form. Since adequate tissue blood flow is a prerequisite for normal metabolic activity, it is a parameter that should merit a place in standard anesthesia or intensive care monitors. That the peripheral tissue blood flow is not routinely displayed may be in part due to the difficulty in quantifying data obtained: flow is not accurately measured as simply as pressure, even by invasive means. It is in the pattern of the waveform that beat-to-beat changes in stroke volume can be better seen than measured, or in the interaction of ventilation and circulation that tests general circulatory performance. The origin and interpretation of these changes are discussed and illustrated with examples. We indicate how new physiological tests of autonomic function and cardiac preload can be developed using pulse plethysmography. The importance and application of the Valsalva effect on the waveform is emphasized. This effect is particularly applicable for monitoring adequate fluid loading and the action of vasodilator drugs, which are both important in anesthesia. Differences between the arterial pulse pressure wave and tissue flow wave are discussed, as well as the cause of certain artifacts, including the wandering dicrotic notch.     

The evolution of ketamine applications in children

Ketamine has found many applications in pediatric anesthetic practice. Insights into the mechanism of action and the pharmacokinetics and pharmacodynamics of its isomers have led to a re‐evaluation of this drug, expanding the range of applications in children. Ketamine is a remarkably versatile drug that can be administered through almost any route. It can also be used for different purposes. The aim of this review is to look at the possible applications of this drug in children.     

Does intrathecal morphine alter the stress response following coronary artery bypass grafting surgery?

PURPOSE: Intrathecal morphine administered prior to coronary artery revascularization (CABG) surgery was studied to determine its effects on the stress response. METHODS: In a single centre, open, randomized clinical trial, first time elective CABG surgery patients, < 75 yr, were studied. Control subjects (n=12) received a standardized anesthetic consisting of fentanyl (maximum cumulative dose of 35 microg x kg(-1)), propofol, and pancuronium. In addition, spinal subjects (n=13) received 1.0 mg (age > 60 yr) or 1.5 mg (age < or = 59 yr) intrathecal morphine prior to induction of anesthesia. Control subjects received continuous i.v. morphine at 2 mg x hr(-1) on arrival in the ICU with i.v. bolus morphine supplementation as required while spinal subjects received bolus i.v. morphine as required. Changes in plasma cortisol and catecholamine concentrations were measured preoperatively, poststernotomy, on admission to ICU, following tracheal extubation, at 0800 hr on the first postoperative day, and 24 and 48 hr after ICU admission. RESULTS: No differences between groups were detected for demographic variables. The percent change in cortisol concentration relative to preoperative values (control vs spinal; (38 (87) vs -41 (46)%: P < 0.05)) was lower in the spinal group on admission to ICU. The percent change in plasma epinephrine levels (control vs spinal) on admission to ICU (285 (337) vs -10 (37)%) and 0800 hr after surgery (314 (341) vs -4 (37)%) was also significantly different. CONCLUSION: Intrathecal morphine only partially attenuated the postsurgical stress response in CABG surgical patients.