Designing humanistic critical care environments.

The critical care environment can be designed to become more humanistic. Consideration of the environmental challenges of noise, lights, color, views, temperature, and comfort is essential. This article identifies the issues and concerns in the design of more humanistic healing in critical care units. Strategies to improve the environment include improving the physical and emotional tone of the unit through creative design, family and pet visitation, sleep promotion, and aromatherapy among others. In a life-threatening illness, attention paid to these concerns may significantly improve quality of life for patients and family.

The importance of social histories for assessing sexually transmitted disease risk.

BACKGROUND: Although identifying risk groups for sexually transmitted diseases based on age or race may be useful for targeting screening efforts, clinicians should recognize that even members of most "low-risk" groups include some individuals at higher risk of infection. GOAL OF THIS STUDY: This case series of generally older people with sexually transmitted diseases illustrates how assumptions regarding age and risk group can lead to missed opportunities for sexually transmitted disease prevention. STUDY DESIGN: Records were compiled from two clusters of patients with sexually transmitted diseases seen at a Springfield, Mass., health center between March and September 1992. RESULTS: Nine patients with a sexually transmitted disease (one with syphilis/human immunodeficiency virus co-infection, one with herpes/human immunodeficiency virus co-infection, two with human immunodeficiency virus infections, and five with syphilis) are described. Eight of the patients are linked epidemiologically. CONCLUSIONS: A social history is essential during a medical encounter for sexually transmitted disease prevention purposes. Relying on assumptions regarding risk groups, as well as sexual activity, age, or other medical conditions, may lead to a patient's level of risk of infection going unrecognized. Discomfort associated with asking the sensitive questions involved in a social history also is a barrier to recognizing risks or infections. Non-judgmental sexual histories are appropriate when evaluating all patients.

Pharmacokinetics of propofol in female patients. Studies using single bolus injections.

The pharmacokinetics of propofol in a dose of 2.5 mg kg-1 given via a vein in the antecubital fossa were studied in 18 patients. Anaesthesia was maintained with nitrous oxide in oxygen in all patients. The effects of pretreatment with fentanyl (n = 6) and maintenance with halothane (n = 6) on the pharmacokinetics of propofol were also investigated. Pretreatment with fentanyl resulted in prolonged apnoea in four patients. No serious side effects occurred. The pharmacokinetics of propofol in unpretreated patients who were maintained with nitrous oxide in oxygen only can be described by a three-compartment open mammalian model with very rapid distribution (T1/2 alpha about 3 min), rapid elimination (T1/2 beta 45 min) and a slower final phase (T1/2 gamma about 300 min). The total body clearance of propofol was rapid (1.91 litre min-1). Propofol was initially distributed into a relatively large central compartment (41.3 litre) and was extensively redistributed (Vss 305 litre; V gamma 722 litre). Throughout the sampling period the mean blood concentrations of propofol for the patients pretreated with fentanyl were about 50% higher than the mean concentrations for patients maintained with nitrous oxide only. Mean propofol concentrations for the patients maintained with halothane were intermediate between those of the other two groups.

The effects of premedication on anaesthesia with propofol ('Diprivan').

The effects of premedication on anaesthesia with propofol (2,6-diisopropylphenol) in a dose of 2.5 mg/kg were assessed. One hundred and twenty female patients were randomized into one of three groups of 40 who received either no premedication, diazepam 10 mg orally, or pethidine 50-75 mg intramuscularly (i.m.) and atropine 0.6 mg i.m. Propofol 2.5 mg/kg was found to be a reliable induction dose. Premedication did not affect the induction time nor the incidence of side effects which occurred in 19% of patients. Apnoea occurred in 44% of patients but was not related to premedication, nor was arterial hypotension. Pain on injection was rare in the antecubital fossa but was a frequent occurrence (30%) in the dorsum of the hand. Recovery was rapid and characterized by lack of emetic sequelae; only one patient had nausea and there was no vomiting. The site of injection was examined postoperatively and venous sequelae were rare.

Infusion rates for anaesthesia with propofol.

The infusion rate of propofol which would produce anaesthesia, when combined with nitrous oxide in oxygen, was studied in 75 fit unpremedicated patients undergoing body surface operations. The infusion rates were based on multiples of the median dose required to produce anaesthesia by intermittent injection in an additional 20 patients. The scatter of doses showed a right skew, for both intermittent and continuous use. This was corrected by loge transformation and derived data presented graphically.

Pharmacokinetic evaluation of ICI 35 868 in man. Single induction doses with different rates of injection.

Blood concentrations of ICI 35 868 have been measured in patients following a single bolus dose of 2 mg kg-1. Three different rates of injection of the anaesthetic agent (3-5s, 20s and 40 or 50s) were examined. Pharmacokinetic indices, derived from blood concentrations of ICI 35 868, were independent of the speed of injection. The blood profiles could be described by a two-compartment open model with a mean alpha-phase half-life of 2.5 min and a mean beta-phase half-life of 54.5 min. The mean total body clearance was 3454 ml min-1. Similar data were obtained from a 4-mg kg-1 dose. The mean recovery time (4.4 min) and concentration of ICI 35 868 at awakening (1.05 micrograms ml-1) were also independent of the rate of injection. Using the derived pharmacokinetic model, predictions of drug concentrations have been made for repeated bolus doses, or infusions, of ICI 35 868.

Recovery from intravenous anaesthesia. Comparison of disoprofol with thiopentone and methohexitone.

Using the endpoints of spontaneous opening of eyes, giving date of birth, sitting up unaided and normal pegboard time, recovery from 2 and 3 mg/kg disoprofol was compared with that from 4 and 6 mg/kg thiopentone and 1.5 mg/kg methohexitone in groups each of 10 unpremedicated patients. The study method differentiated between recovery from the two doses of disoprofol and thiopentone at the first two endpoints only. A between-drug comparison showed early recovery was slightly faster with thiopentone than with equivalent doses of the new drug while no differences were detected between the recovery from equivalent doses of methohexitone and thiopentone. The differences found in this study are felt to be of no clinical significance and recovery from anaesthesia with disoprofol would not be expected to be any slower than that from equivalent doses of thiopentone.

Effect of preanaesthetic medication on anaesthesia with ICI 35, 868.

The effect of three commonly used premedicants and a control on anaesthesia with ICI 35, 868 is described. Two randomized studies were performed--one a group study of induction characteristics at 2 mg kg-1 and the other a detailed study in patients undergoing minor gynaecological surgery with an induction dose of 1.5 mg kg-1 and maintenance with incremental doses plus 66% nitrous oxide in oxygen. Premedication had little effect on the already good induction characteristics. Only heavy opiate premedication produced reliable induction at 1.5 mg kg-1, but with an increase in side-effects. Diazepam appears to be the premedicant of choice, although the overall frequency of pain on injection has not been affected by premedication.

Comparison of the effect of diisopropyl phenol (ICI 35, 868) and thiopentone on response to somatic pain.

The response to somatic pain with sub-hypnotic doses of ICI 35, 868 (diisopropyl phenol in cremophor) and thiopentone was compared using tibial pressure algesimetry. Studies were also carried out following recovery from larger doses of both drugs. The patients underwent gynaecological procedures using only one of the two i.v. agents and nitrous oxide in oxygen. The studies confirmed the known antanalgesic action of thiopentone and demonstrated that diisopropyl phenol has an analgesic action which is an attractive feature in an i.v. anaesthetic agent.

Effects of neostigmine and pyridostigmine on serum cholinesterase activity.

Serum cholinesterase activities were measured from 270 minutes in patients following administration of neostigmine or pyridostigmine for the reversal of pancuronium block in groups of seven patients each. The enzyme activities were significantly depressed by neostigmine for four hours and by pyridostigmine throughout the whole period of study. Whereas the immediate effects of neostigmine were more intense, the effects of pyridostigmine beyond the first 30 minutes were more profound. The clinical relevance of these findings is discussed.

Comparison of atropine and glycopyrrolate in a mixture with pyridostigmine for the antagonism of neuromuscular block.

Neuromuscular block was antagonized using pyridostigmine 250 micrograms kg-1 in two groups of 50 patients; one group received atropine 20 micrograms kg-1 and the other glycopyrrolate 10 micrograms kg-1 with the anticholinesterase drug. Atropine was associated with a greater initial tachycardia than was glycopyrrolate. The subsequent bradycardia was also greater in this group, although the decreases in heart rate were smaller than those generally observed following mixtures of atropine and neostigmine. Arrhythmias were transient and required no treatment in either group. Better control of secretions was achieved with glycopyrrolate.

Use of di-isopropyl phenol as main agent for short procedures.

The use of di-isopropyl phenol (Diprivan) for induction of anaesthesia was assessed in doses ranging from 1 to 3 mg kg-1. With less than 1.75mg kg-1 not all patients were anaesthetized; 2.0 mg kg-1 appeared to be a satisfactory induction dose. Involuntary muscle movement, cough and hiccup at induction were rare with any dose studied. However, the frequency of hypotension and respiratory depression were related to the dose given. Pain on injection was uncommon when the drug was given into an antecubital vein, but occurred in 39% of patients when injected to the back of the hand or wrist. Recovery was rapid, and characterized by lack of emetic sequelae. Di-isopropyl phenol 1.5 - 2.0 mg kg-1 given rapidly during reactive hyperaemia can produce anaesthesia in one arm-brain circulation time. A reaction involving flush, hypotension, cough, laryngospasm and bronchospasm occurred in one patient receiving 2.5 mg kg-1 given over 20 s.

Evaluation of midazolam as an intravenous induction agent.

Midazolam, a new water-soluble benzodiazepine, was investigated as an intravenous anaesthetic agent in 260 adult patients in doses ranging from 0.15 to 0.5 mg/kg using a variety of premedications. Its onset of action was generally slow, taking up to 3 minutes to exert its maximum effect. A wide variability in response was found in that some unpremedicated patients were satisfactorily anaesthetised with 0.15 mg/kg while other were only moderately sedated following doses of 0.5 mg/kg. Less variability was found in the elderly who also required smaller doses. Narcotic premedication potentiated the sedative effect of midazolam. Few respiratory or cardiovascular effects were noted apart from hiccough following the larger doses. The incidence of venous sequelae was much lower than that found following diazepam.

Minaxolone: an evaluation with and without premedication.

Minaxolone, a water-soluble steroid intravenous anaesthetic, has been used in clinical trials for induction and maintenance in patients presenting for minor operations. A standard induction dose of 0.5 mg/kg was given. There was a low incidence of pain on injection and venous sequelae. Excitatory effects occurred commonly at induction but these were reduced by opiate premedication. The frequency of uneventful induction was significantly greater when the 5 mg/ml solution of minaxolone was given at a rate of 6 ml/minute than at a rate of 24 ml/minute. Minaxolone has been withdrawn from clinical trials following equivocal toxicological findings in rats which require further investigation.

The influence of dosage and premedication on induction of anesthesia with minaxolone.

Minaxolone, a new steroid induction agent, was administered to unpremedicated patients at three dose levels and at 0.5 mg . kg-1 to patients receiving three different premedicant regimes. The main side effects observed at induction were involuntary muscle movements but hypertonus and tremor were also seen. Respiratory complications consisted mainly of hiccough. Over the range of doses studied only the latter complication appeared to be dose-related. Premedication with diazepam and especially opiate combinations reduced the frequency and severity of excitatory effects and respiratory upset and increased the proportion of acceptable anesthesia. Marked respiratory depression and hypotension of greater than 20 mm Hg were rare even after opiate premedication.