J.B. Cazalaà

Mastocytoses et anesthésie

Mastocytosis are characterized by an accumulation of abnormal mast cells in various tissues. Their incidence is estimated at 1/150,000 patients. Pure cutaneous mastocytosis which are mainly observed during childhood may resolve spontaneously during adolescence, whereas systemic mastocytosis involving one or more organs or tissues are more observed in adults. The initial event leading to mastocytosis is believed to be related to activating mutations in c-kit receptor, thus resulting in increased proliferation of mast cells precursors, migration in various tissues and degranulation leading to clinical signs. This nosologic entity does not belong to allergic diseases. Their perioperative management involves a multidisciplinary approach. The degranulation of mast cells with subsequent clinical symptoms can be triggered by psychological, chemical, traumatic, physical (rubbing, extreme temperatures...) agents. Avoiding these triggers should be realized whenever possible according to each patient. The premedication has not proven its efficiency. Tryptase measurement is part of the preoperative biological assessment. The clinical signs severity is related to the cardiovascular homeostasis disturbances (arterial hypotension, cardiovascular collapse, cardiac arrest). The cardiovascular symptoms do not correlate to the cutaneous versus systemic description of the disease. The drug of choice for the treatment of the severe cardiovascular signs is epinephrine associated to vascular loading. The aim of this literature review is to suggest the different modalities of perioperative care of patients with mastocytosis.

Appareils électriques de perfusion : critères de choix et analyse comparative de 45 modèles disponibles en France

This study compared 45 electric infusion devices, either constant flow pumps or syringe pumps, available in France. These devices were tested for start-up delay, time to alarm following occlusion, bolus following occlusion, accuracy of flow rate and pressure output. Ergonomic, environmental and various technical criteria such as safety in continuous perfusion, correct positioning of infusion sets, air in line and end of perfusion detection were also considered. Users can compare these devices in easy to read tables. The newest devices include systems improving the quality of flow.

Les appareils électriques de perfusion

Electrical infusion devices are specifically aimed to maintain an accurate and constant flow rate. The infused agents can be allocated into three categories of risk, according to their therapeutical index and their infusion rate. Each category requires infusion devices with the corresponding performances. Moreover the choice of a device depends also on ergonomical and environmental criteria as the area of use (e.g. ambulatory patient, transport, neonates, intravenous anaesthesia).Electrical infusion devices are specifically aimed to maintain an accurate and constant flow rate. The infused agents can be allocated into three categories of risk, according to their therapeutical index and their infusion rate. Each category requires infusion devices with the corresponding performances. Moreover the choice of a device depends also on ergonomical and environmental criteria as the area of use (e.g. ambulatory patient, transport, neonates, intravenous anaesthesia).

Mélangeurs de gaz défectueux, cause de rétropollution du circuit de distribution des gaz médicaux

A defective Air/O2 mixer of a ventilator located downstream of the gas outlets of two pipelines is a potential cause of retropollution. Retropollution of O2 with Air or vice versa carries a risk of either a) a hypoxic gas mixture delivery during anaesthesia, including O2-N2O administration, when the O2 pipeline supplies Air instead of O2, or b) a hyperoxic gas mixture delivery in the intensive therapy unit for neonates during administration of a O2-Air mixture, when the Air pipeline supplies O2 instead of Air. A defective O2/N2O flowmeter-mixer of an anaesthesia machine, with N2O flow control by O2 through a differential pressure manometer, can cause retropollution of O2 supply pipeline with N2O or vice versa. The prerequisite for retropollution is the association of three events: build-up of a pressure difference between the two gas lines; defective or absent back-flow check value in the circuit of the gas at a lower pressure; one of the following defects: a) the pressure equilibrating valves of the mixer cannot amend the pressure difference and allow a gas reflow at the gas mixture outlet; b) leak in the diaphragm of a pressure equilibrating valve; c) defective bypass supply valve. The optimal means for the recognition of a pipeline contamination by another gas is the O2 analyzer, especially in anaesthetic areas where the presence of N2O and Air carries the risk of a hypoxic gas mixture delivery. The mixer or flowmeter-mixer responsible for retropollution can be recognized in plunging successively the various quick couplers underwater into a glass, while the others remain connected to their outlets and the mixer set at a O2 concentration of 50 vol% or the flowmeters set at a similar flow. In case of retropollution, the gas reflow produces bubbles. It is recommended: a) in anaesthetic areas to set the O2 pressure at about 0.2 bar above that of Air and the latter at a pressure of about 0.2 bar above that of N2O; b) in intensive therapy units for neonates, to set the Air pressure at about 0.2 bar above that of O2; c) in all areas to disconnect from the gas outlets the devices equipped with a mixer or a flowmeter-mixer when not in use.

Pour ou contre les circuits anesthésiques accessoires: I. Arguments pour leur utilisation

In addition to the circle breathing system, which represents the main circuit of the anaesthetic machine, the use of an accessory breathing system (ABS), either a partial rebreathing system according to Maplesons classification, or a system including a non-rebreathing valve, is appropriate for the anaesthetic management of many patients, depending on their physical status, age, indication and duration of surgery. The same safety rules, namely full checking procedure before use of the system and monitoring of inhaled gases and end-tidal CO2 must be applied as for the main circle system. Potential complications resulting from non compliance with these rules cannot be considered valuable reasons for denying the use of breathing systems that have safely been used for decades in millions of patients.

Circuits anesthésiques accessoires: vérification avant utilisation

Accessory or ancillary anaesthesia breathing systems can be defined as all those connected to the fresh gas outlet of the anaesthetic apparatus and used instead of the circle system associated with the ventilator, which is the main circuit. They include: the Mapleson systems, the systems with a nonrebreathing valve and the disposable systems with a carbon dioxide absorber. They can be a cause of major accidents when not checked before and monitored during use. This technical note describes techniques of preanaesthetic checking and monitoring during anaesthesia.

Leucoagglutination pulmonaire mortelle après administration de plasma frais congelé

A case is reported of a 73 year old female patient who died during surgery for enlarged nephrectomy as a result of a massive non-cardiogenic pulmonary oedema. She had been given 2 red cell concentrates (450 g) and 3 fresh frozen plasma units (900 g). A postmortem examination did not reveal any pulmonary embolus, acute myocardial infarct, haemorrhage or cardiac tamponade. Further tests on the sera of the 5 plasma donors revealed a neutrophil-specific anti-NA2 antibody. Alveolar leukostasis was confirmed on the postmortem lung slices. This type of transfusion accident occurs for about 1 in 5,000 units transfused, fortunately not all as serious. This case confirms once more that fresh frozen plasma is not the ideal treatment for acute hypovolaemia, 4% human albumin being safer.

Control de los dispositivos médicos

Resumen Los organismos sanitarios europeos, 20 anos despues de los estadounidenses, han establecido un dispositivo de control poscomercializacion de los equipos. En cada establecimiento, un responsable local reune y controla las notificaciones de incidentes antes de transmitirlas a la administracion publica. Esta puede decidir que se modifique el material en cuestion o incluso que se retire del mercado. A veces, la anestesia y los cuidados intensivos estan implicados en una tercera parte de los incidentes comunicados. Cada notificacion debe proporcionar informacion tan detallada como sea posible sobre el caso que se plantea. Sobre todo, es sumamente importante precisar las caracteristicas del paciente, las condiciones de utilizacion del aparato y el entorno con el fin de identificar la procedencia del incidente. Una utilizacion defectuosa representa una causa remediable y su reconocimiento exige un gran esfuerzo de informacion y formacion.