G. Barrier

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).

Surveillance continue de la SV˙o2 au cours de l'anesthésie pour chirurgie pulmonaire

The multiplicity of potential causes of variations in mixed venous oxygen saturation (Sv2) during one lung ventilation (OLV), including a constant ventilation/perfusion mismatch, explains that it has been suggested as a routine monitoring procedure. To assess its usefulness, 12 adults undergoing OLV were monitored during surgery with an Oximetrix® pulmonary catheter, placed on the side opposite to the surgical field under fluoroscopic control. Seventy two complete sets of haemodynamic measurements were obtained at 6 different times during surgery. We studied the ability of changes in Sv2 to predict changes in arterial oxygen saturation (Sao2), cardiac output (CO), and venous admixture (VA) by calculating sensitivities (Se), specificities (Sp) and predictive values with regard to these variables. There were no complications due to the protocol. However left-sided catheter placement failed in four cases. Correlation between optical and measured Sv2 was very strong (r=0.94; p<0.001). Sv2, oxygen consumption (V˙o2) and the rate of oxygen extraction remained constant throughout the procedure, even when CO, mean arterial pressure, VA, Sao2 and Pao2 varied. Clamping the pulmonary artery returned VA, Sao2 and Pao2 values to those found before OLV, but produced a significant decrease in CO. Sv2 had low Se and Sp for changes in other variables (CO: 76±7, 48±9; Pao2: 79±6, 59±9; VA: 54±7, 48±7 respectively). In this type of surgery, alterations in variables related to oxygen are probably balanced by haemodynamic changes. In fact, according to Ficks formula, Sv2 is almost completely determined by Sao2 and CO, when V˙o2 and haemoglobin remain stable. However, a decrease in Sv2 should alert the clinician to a potential change in haemodynamic indices or to a problem in some component in the oxygen delivery system. Sv2 values do not add to or correlate well with other data, but facilitate their continuous monitoring.

Ventilation par sonde métallique pour la chirurgie laryngée au laser CO2

One of the risks of laryngeal laser surgery is the ignition of the disposable plastic endotracheal tubes used for ventilation. In 1985, Hunton and Oswal (Anaesthesia, 40 : 1210, 1985) developed a metallic tube which is now available in France. In this study, the tube has been tested on 30 patients undergoing this type of surgery. The tube was sterilized in glutaraldchyde before re-using it. There never was any problem with placing the tube and surgical conditions were satisfactory. There was neither incident due to the laser, nor any difficulties with the use of high-frequency jet-ventilation. The blood gas values were satisfactory (mean Pao2 : 19.4 ± 4.2 kPa ; mean Paco2 5.0 ± 0.46 kPa). After a use in 30 consecutive patients, the tube was not damaged. The advantages and disadvantages of this tube are discussed, considering the other types of special laser surgery endotracheal tubes. This metallic tube is not flammable, can be used several times, occupies only a small space and does not hurt tissues. Moreover, it is cheaper than disposable tubes when the price is calculated per patient. It would therefore seem that Hunton and Oswals metallic tube, used with high-frequency jet-ventilation is a good alternative for tubes used today.

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.