Incidence of sinusitis in patients with nasotracheal intubation.

Sinusitis is a complication known to accompany nasotracheal intubation, but its frequency has not been well documented. Twelve patients suffering from cerebral haemorrhage or from cranial trauma and treated with mechanical ventilation were examined for radiological and bacteriological signs of sinusitis with CT-scanning, and cultures of nasal pus discharge. All patients showed radiological signs of sinusitis within 3 days after intubation. They all developed fever, six with a known focus outside the sinuses. There was an even distribution of Gram-negative and Gram-positive bacteria. It is concluded that sinusitis should be considered where fever occurs without known focus in patients with nasotracheal intubation.

CO2 production after suxamethonium and diazepam.

The CO2-production and degree of relaxation after increasing doses of suxamethonium were measured in seven patients undergoing alloplastic surgery of the hip. The study indicates that the CO2-production rises following the injection of increasing doses of suxamethonium. Another group of patients received diazepam 0.1 mg kg-1 before the injection of suxamethonium 1 mg kg-1. CO2-production was significantly reduced compared to CO2 production when suxamethonium was not preceded by diazepam. It is suggested that diazepam in doses larger than 0.1 mg kg-1 might be effective in preventing fasciculations and postoperative muscle pains before the injection of suxamethonium in a dose of 0.5 mg kg-1.

Distribution of expiratory gas and rebreathing in a T-piece modification combined with a PEEP valve.

T-piece modifications with PEEP valves are often used in weaning from mechanical ventilation or for intubated patients not requiring ventilatory support. Distribution of expiratory gas and the extent of rebreathing in a T-piece modified with an inspiratory reservoir (ICR) and with a PEEP valve were studied in a model with various fresh gas flows (FGF), tidal volumes and frequencies at three valve settings: 0 cmH2O (ZEEP) and PEEP of 5 and 10 cmH2O (0.490-0.981 kPa). Two types of distribution of expiratory gas were delineated: type one with expiratory gas in the inspiratory limb (IL) and a high ratio of the maximum CO2 content and corresponding end-expiratory CO2 concentration in the expiratory limb (EL) (FmaxCO2/FECO2) and a type 2 with no detectable alveolar gas in the IL and a low ratio of FmaxCO2/FECO2. The use of PEEP did not increase the amount of alveolar gas in the system, and no increase occurred in the end-expiratory CO2 concentration. The investigated system is in fact a Mapleson A system. The ratio of FGF to minute ventilation just preventing rebreathing during spontaneous ventilation is approximately 1, in contrast to 3 in other modifications. These advantages minimize the risk of rebreathing, even when the minute ventilation rises to that of the fresh gas flow. The T-system with a compliant inspiratory reservoir and a PEEP valve can, in most clinical weaning situations, satisfy the inspiratory peak flow of different respiratory patterns with a standard FGF of 15 l X min-1.

Distribution of expiratory gas and rebreathing in T-piece modifications used in weaning.

The simple T-piece is frequently used as a weaning system during respirator treatment. It is modified with an expiratory non-compliant reservoir (EnCR), an inspiratory compliant reservoir (ICR) and/or an expiratory one-way valve. The distribution of expiratory gases and rebreathing were studied in a model set-up in the corresponding systems at different fresh gas flows (FGF) and tidal volumes (VT). An EnCR produces no change, whereas an ICR causes the expiratory gas to flow into the inspiratory limb, an effect which is intensified by the presence of an expiratory valve. With a falling FGF and a rising VT, increasing amounts of expiratory gas are found in the inspiratory limb in the modifications with an ICR. However, this gives rise to rebreathing in the valve modification with a low FGF and high VT. The modification of the T-piece with an ICR but without a one-way valve is advantageous, as this system combines only slight dilution via the expiratory limb and a minimal risk of rebreathing.

Acute valproate intoxication: biochemical investigations and hemodialysis treatment.

A 20-year-old female was comatose for several days after intoxication with 75 g sodium valproate (VPA). She was successfully treated with hemodialysis, hemoperfusion, i.v. infusion of glucose, and given intensive care. Although a peak serum VPA of 2120 micrograms/ml (14720 microM) was registered 8 1/2 h after drug intake, no definite drug-related hepatotoxic or thrombocytopenic effects were seen. The only signs of organotoxicity were slight increases in serum amylase and a transient proteinuria. Further acute biochemical alterations were a decrease in serum calcium, an increase in plasma ammonia as well as in serum propionate, and elevated urinary excretions of adipic and suberic acid. Analysis of amino acids in serum revealed a stable increased level of glycine.

Admixture of atmospheric air in the T-piece used as a weaning system.

Ayre's T-piece may be used for intubated, non-anaesthetized patients requiring an oxygen supplement or humidified gas mixtures. The system has the disadvantage that atmospheric air (VAD) enters through the expiratory leg when the inspiratory flow and therapeutic gas flow (TGF) are not equal. This admixture can be reduced in the simple T-piece by the addition of either a compliant inspiratory reservoir, or a compliant inspiratory reservoir and an expiratory unidirectional valve. These three systems have been studied in a model investigation using different tidal volumes (VT), respiratory frequencies, and therapeutic gas flow. VAD was measured using a pneumotachograph and the inspiratory tidal volume was measured with a Wright Respiratory Monitor. The ratio VAD/VT was employed as an expression of the admixture of atmospheric air during inspiration. The introduction of a compliant inspiratory reservoir to the simple T-piece results under all conditions in a considerable reduction in VAD/VT. A further reduction was obtained by introducing an expiratory unidirectional valve into the system - however, with the result that the previously open system is turned into a closed system. When selecting a weaning system, the risk to the patient of the discontinuation of the gas flow should therefore be weighed against the advantages obtained by a reduction of the admixture.