Adjusted transfusion triggers improve transfusion practice in orthopaedic surgery.

Although blood transfusion has never been safer, there remains concern about adverse effects. We designed guidelines, the 6-8-10-Flexinorm, based on the conditions which are relevant to the decision to transfuse. To evaluate these new guidelines, we performed a case-control study in patients undergoing elective primary total hip replacement. The study consisted of two parts. In the first part, physicians were strongly encouraged to use the new guidelines; in the second part, only registration took place. During the first and second part of the study, the use of packed red cells (PRC) in Hospital A (study hospital) decreased from 1.1 +/- 1.5 to 0.6 +/- 1.2 and 0.3 +/- 0.9 units, whereas in Hospital B (control), the use of PRC remained unchanged (1 +/- 1.5, 1 +/- 1.7 and 1 +/- 2 units). In the prestudy groups, 43% of the patients in Hospital A were transfused compared to 45% in Hospital B. In the first and second part of the study, 27%, respectively, 14% of the patients in Hospital A were transfused compared to 40% in both periods in Hospital B. The new guidelines lead to a reduction in the use of allogeneic blood and a decrease in the number of patients transfused.

Epidural anaesthesia in a child with possible spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a rare lower motor neurone disease in which anaesthetic management is often difficult as a result of muscle weakness and hypersensitivity to neuromuscular blocking agents. Neuraxial anaesthesia is controversial in these patients; however, some cases have been reported in which neuraxial anaesthesia has been used without neurological sequelae. We describe a 7-year-old patient with possible SMA scheduled for a Grice-arthrodesis. Because of previous prolonged postoperative drowsiness and poor oral intake, we decided to use an epidural technique with sevoflurane sedation and spontaneous ventilation to avoid the use of muscle relaxants and systemic opioids and consequently admission to the intensive care unit. After 3 days, the epidural analgesia was stopped and the patient regained her preoperative motor function within 5 h. Despite the controversy surrounding the use of neuraxial techniques in neuromuscular disease, we found no well-founded basis for this in patients with SMA in the literature.

Farewell to a fallen warrior.

In the Summer of 1999, Kemp Burleson had what he thought was going to be a rather routine annual physical exam. By his own estimate, at 37-years-old he was in perfect health. There was no warning of what was to come. At his wife's insistence, he asked for a blood test to determine if his cholesterol was elevated, as there was a family history of heart disease. Within days, the results were in. They were not good. It was not a cholesterol problem. He had leukemia and would need a bone marrow transplant to increase his odds for survival. In spite of the attempts to extend his life, he lived only several months following that initial diagnosis. The following is the eulogy that was inspired by our time together in the hospital.

The nursing triage process: a video review and a proposed audit tool.

OBJECTIVE: To review the activity of the nurse triage process. SETTING: The triage room for adults attending the accident and emergency department of the Cardiff Royal Infirmary. METHODS: 226 triage processes were videotaped over 31 h during July 1994. Activities were subsequently analysed using a specially designed chart. RESULTS: Areas for improvement in staff communication skills and patient privacy were identified. CONCLUSIONS: The use of video in the triage room allows assessment of the triage process and is a valuable aid to training. Additionally, a potential visual audit tool has been identified.

Dose-response relation, neuromuscular blocking action, intubation conditions, and cardiovascular effects of Org 9273, a new neuromuscular blocking agent.

The ED50 and the ED90, the time-course of the neuromuscular block, the intubation conditions, and the cardiovascular effects of Org 9273, a new steroidal nondepolarizing neuromuscular blocking agent, have been evaluated in 41 anesthetized patients. From cumulative dose-response curves the ED50 and ED90 were calculated to be 175 and 300 micrograms/kg, respectively. The time-course of neuromuscular blockade after 300- and 500-micrograms/kg doses of Org 9273 appeared to be similar to that of equipotent doses of vecuronium. The neuromuscular block was characterized by a fast initial rate of block development. High-dose Org 9273 (1 mg/kg = 3-4 times the ED90) had a clinical duration comparable to an intubating dose of pancuronium, but a considerably more rapid onset and recovery index. Three hundred micrograms per kilogram and 500 micrograms/kg Org 9273 produced good to excellent intubation conditions 1 min after administration. Org 9273 in a dose of 0.5-2 times the ED90 produced no cardiovascular changes; however, 3-4 times the ED90 increased heart rate 20%-25% (P less than 0.001), probably due to a vagolytic effect.

Maintenance of surgical muscle relaxation by repeat doses of vecuronium and atracurium at three different dose levels.

The time-course of the neuromuscular effects of vecuronium (n = 25) and atracurium (n = 25) has been compared at three different levels of maintenance dose in anaesthetized patients. Following intubation with vecuronium 0.1 mg kg-1 or atracurium 0.5 mg kg-1, surgical muscle relaxation was maintained by using increments of equipotent maintenance doses equivalent to 0.5, 1.0 and 1.5 x ED95 for each drug. Repeat doses were administered each time the twitch height, depressed by the previous dose, returned to 25% of its control value. The apparent increase in the duration of action, i.e. the difference between the duration of the last and the first maintenance dose, did not reach statistical significance and approximated 3 +/- 2, 6 +/- 4, 11 +/- 5 and 3 +/- 2, 8 +/- 13, 5 +/- 7 min following the low, medium and high maintenance doses of vecuronium and atracurium, respectively.

Dose-response relation and time course of action of pipecuronium bromide in humans anesthetized with nitrous oxide and isoflurane, halothane, or droperidol and fentanyl.

The dose-response of pipecuronium bromide, the time course of its neuromuscular blocking effects, and the reversibility of the residual block by neostigmine and edrophonium have been investigated in patients undergoing various types of anesthesia. The estimated doses of pipecuronium required for 95% depression of the twitch height were 44.6, 46.9, and 48.7 micrograms.kg-1 during anesthesia with nitrous oxide (65%) and isoflurane (group 1), halothane (group 2), or droperidol/fentanyl (group 3), respectively. The potentiating effects of the volatile anesthetics were reflected by the significant prolongation of the duration of both initial (50.0 +/- 4.3, 36.0 +/- 3.3, and 29.0 +/- 2.0 minutes) and maintenance doses (56.0 +/- 2.5, 49.5 +/- 3.3, and 41.2 +/- 1.6 minutes) of pipecuronium during anesthesia with nitrous oxide and isoflurane, halothane, or droperidol/fentanyl, respectively. Both edrophonium chloride (0.5 mg.kg-1) and neostigmine methylsulphate (40 micrograms.kg-1) promptly reversed the residual block induced by pipecuronium. No side effects attributable to pipecuronium were seen in this study.

Histamine metabolism after adverse reactions due to d-tubocurarine administration.

We investigated histamine release in five female patients, submitted for gynaecological surgery, after intravenous administration of the neuromuscular blocking agent d-tubocurarine. In these patients, we measured the plasma levels of histamine and its metabolites, N tau-methylhistamine and N tau-methylimidazoleacetic acid, making use of mass fragmentographic methods. The newly developed determination of plasma N tau-methylimidazoleacetic acid had a within-day coefficient of variation of 2.7% (n = 10). Normal values of N tau-methylimidazoleacetic acid in plasma ranged from 41.3-75.6 nmol/l (n = 13). All five patients developed anaphylactoid reactions: two patients showed severe systemic reactions, one patient a minor systemic reaction and two had skin reactions only. Plasma histamine and N tau-methylhistamine levels appeared to be the most reliable biochemical parameters for confirming both the occurrence and severity of an anaphylactoid reaction. In comparison with plasma histamine, the determination of plasma N tau-methylhistamine is less hampered by artefacts caused by blood collection and plasma preparation. Together with the fact that the increase in plasma N tau-methylhistamine levels after anaphylactoid reactions lasts much longer than the increase in plasma histamine levels, this leads to the conclusion that the determination of plasma N tau-methylhistamine is a useful retrospective parameter for histamine release in this type of pathological state. The plasma N tau-methylimidazoleacetic acid levels fluctuated considerably, showing only a significant increase after administration of d-tubocurarine in the two patients who had severe anaphylactoid reactions. This parameter is, therefore, less useful in such studies.

Measurement of N tau-methylhistamine concentrations in plasma and urine as a parameter for histamine release during anaphylactoid reactions.

N tau-methylhistamine concentrations in plasma and urine were determined using a newly developed simultaneous determination for histamine and N tau-methylhistamine, based on isotope dilution mass fragmentography. Three groups of patients were investigated: patients receiving intravenously-administered iodamide for excretory urography, patients receiving a wasp-sting challenge, and patients treated with an intravenously-administered muscle relaxant. In all patients showing a distinct systemic anaphylactic or anaphylactoid reaction histamine and N tau-methylhistamine concentrations were found to be elevated. From the results of this study it can be concluded that N tau-methylhistamine in plasma and urine is a good parameter for histamine release, and that the determination of this histamine metabolite are less hampered by possible artefacts (due to basophil disrupture, a very short half-life time or bacterial production) than determinations of histamine itself.

Etomidate-analgesic combinations for the induction of anaesthesia in cardiac patients. Part I: Studies in patients with coronary artery disease.

UNLABELLED: In a total of 150 patients undergoing coronary revascularization procedures etomidate was given for the induction of anaesthesia using 12 different dosages and combinations with piritramide, morphine, fentanyl and nitrous oxide. The aim of this study was to establish a method which would result in the smallest possible changes in arterial blood pressure and heart rate during the whole of the induction period, including the stressful phase of endotracheal intubation. In 68 patients cardiac output and pulmonary artery pressure were also measured. RESULTS: 1. In general, more favourable results were obtained when anaesthetic drugs were administered extremely slowly (e.g. by infusion) and according to a standardized dosetime regime. Conversely, the commonly used method - slow incremental injections according to the estimated requirements of the individual patient - led to much greater variations of arterial pressure, especially when fentanyl was combined with etomidate. 2. Combinations of etomidate and morphine led to unsatisfactory results. Dependent on the dose given, hypertension or hypotension were commonly seen. When piritramide was substituted for morphine much more stable haemodynamic conditions were obtained. 3. Surveying our investigations to find the most suitable dose relationship between the hypnotic, etomidate, and the opioid analgesic, piritramide, only small and negligible differences were found: comparing two procedures for the induction of anaesthesia using either high dose piritramide (3 mg . kg-1 given over 10 min), supplemented by low dose etomidate (0.1 mg . kg-1 given over the first 2 min) or an etomidate infusion (50 gamma . kg-1 . min-1) supplemented by a low dose piritramide (0.3 mg . kg-1 given over 1 min) excellent results were found in both groups. 4. In contrast, studies aimed at achieving equally favourable results using the combination of etomidate-fentanyl suggested that the safe dose-range of fentanyl is very narrow: etomidate-infusion (50 gamma . kg-1 . min-1) together with fentanyl 3 gamma . kg-1 led to unacceptable rises in blood pressure and heart rate after intubation, and the larger dose of 6 gamma . kg-1 fentanyl frequently led to hypotension.

Comparison of flunitrazepam and diazepam for oral premedication in older children.

A double-blind trial was conducted of two benzodiazepines, flunitrazepam and diazepam, given orally to 142 children (30 kg in weight or heavier) undergoing routine surgery. Flunitrazepam was associated with greater sedation before operation and less vomiting after operation than diazepam. Flunitrazepam caused a greater frequency of amnesia for the periods of induction and immediately after operation. Plasma concentrations were measured in 65 children and were found to be significantly greater in those children having amnesia for the induction period in both flunitrazepam and diazepam groups. In the diazepam group, plasma concentrations were significantly smaller in those who vomited than in those who did not vomit.

Performance and application of the Quantiflex air/oxygen mixer.

The Quantiflex air/oxygen mixer is designed to dispense mixtures of air and oxygen with separate controls for total gas flow rate and oxygen concentration of the mixture within the range 21-100%. A monitoring flowmeter is provided for the mixture and also, as a safety measure, for the oxygen component. This serves as an indicator that oxygen is flowing and also permits independent calculation of the oxygen concentration of the mixture. Delivered oxygen concentrations were found to be within +/- 2% of the indicated value at flow rates between 4 and 12 litre/min with the input pressures of either or both gases at 208-415 kPa (30-60 lbf/in2.) gauge, and with or without an output pressure of 20 kPa. At total flow rates of 1.5-2 litre/min there was a maximum discrepancy of 4% below and 8% above the indicated concentration in some delivered concentrations. Acceptability, ease, accuracy and quickness of use by nurses were compared with current methods using separate flowmeters for air and oxygen and calculating the required flow rates by means of arithmetic, graph and special-purpose slide-rule (Blease). The Quantiflex prototype was the most acceptable, the easiest, the most accurate and the fastest of the techniques investigated.