Systemic lithium reabsorption from lithium-chloride-coated heat and moisture exchangers.

OBJECTIVE: To evaluate possible reabsorption and systemic effects of lithium released by lithium-chloride-coated heat and moisture exchangers (HMEs) during prolonged mechanical ventilation. DESIGN: Prospective study, including all patients mechanically ventilated for 5-30 days. SETTING: A 7 bed general-traumatological ICU in a University Hospital. PATIENTS: 27 consecutive ICU patients, admitted following trauma, neurosurgery and respiratory insufficiency, mechanically ventilated for at least 5 days, with a lithium coated hygroscopic HME in the circuit. MEASUREMENTS AND RESULTS: Serum lithium levels were measured daily, with a standard laboratory spectrophotometric method, from admission to discharge from the ICU, and showed a reabsorption of lithium in all the patients; in the adults, levels were 5 to 15 times lower than therapeutic range, while in a child therapeutic and even toxic levels were reached. CONCLUSIONS: LiCl coat enhances HMEs' performance greatly, but reabsorption and systemic action must be considered. In adults, serum lithium levels were lower than the therapeutic range, but lithium is effective at low concentrations and it has a narrow therapeutic range; moreover, toxicity can be observed within this range too. In children, the risk of toxicity is much greater. When lithium coated HMEs are used, the risk/benefit ratio between good performance and systemic reabsorption must be evaluated carefully.

Fatal anaphylactic shock during a fluorescein angiography.

The Authors describe an extremely rare fatal case (sixth case in the literature) of anaphylactic shock following a fluorescein angiography. This is the first report in which the diagnosis of anaphylactic reaction to the dye was made through laboratory analyses. The diagnosis of fatal shock due to sodium fluorescein was made based on clinical, laboratory and immunohistochemical data. Mast-cell tryptase was dosed in serum and a pulmonary immunohistochemical evaluation was performed. Tryptase, a neutral protease of human mast-cells is a potentially important indicator of mast-cell involvement in anaphylactic events.

[Continuous blood gas monitoring in intensive care units]. / Mesure en continu des gaz du sang en unité de soins intensifs.

The measurement of O2 and CO2 transport in the arterial and venous mixed blood constitutes the intersection between haemodynamic data and expiratory-inspiratory gases. The arterial-venous difference in O2 (a-v-DO2) and the venous arterial difference in CO2 (v-a-DCO2) calculated from the data of PA, PO2, PCO2 (read by an ABL4 Radiometer) revealed a close correlation with a a-v-DO2 measured directly by means of the LEXO2 (r = 0.99) or with VCO2 measured in expired gases by a capnograph (r = 0.99). In heart surgery the "on-line" monitoring of VCO2, a-v-DO2 and related parameters (REE = Resting Energy Expenditure) in the operating room and in ICU by means of a PDMS (Patients Data Management System) provides very useful information which, when integrated with haemodynamic parameters, allows a better understanding and better care of critical patients.

[CT 1341 as a hypnotic in continuous peridural anesthesia of the high-risk urologic patient]. / Il CT 1341 come ipnotico nella peridurale continua nel paziente urologico ad alto rischio.

Experience with althesin as the covering anaesthetic in the continuous peridural management of high-risk urological patients is reported. It was found that althesin fully lived up to expectations, since patients went to sleep without difficulty and awoke peacefully, as though from natural sleep. The drug did not interfere with the peridural procedure in any way. Use of the technique, it is felt, should be encouraged, since it is advantageous both to the patient and the anaesthetist, to whom a liquid anaesthetic offers the only chance of getting away from the damage caused by volatile types.

Hypermetabolic response after hypothermic cardiopulmonary bypass.

Sixteen patients undergoing hypothermic cardiopulmonary bypass for open heart surgery were studied prospectively. Oxygen consumption and CO2 production showed a marked increase during the first 6 h postoperatively. Consequently, the measured resting energy expenditure was markedly elevated compared to the predicted energy expenditure. This hypermetabolic response occurred simultaneously with maximum spontaneous rewarming after the end of surgical procedures. Ventricular function was low throughout the postoperative period, and no cardiac response to increased energy requirements was recorded. On the contrary, marked increases in arteriovenous oxygen and CO2 difference were observed during the period of highest resting energy expenditure. We conclude that the first hours after hypothermic cardiopulmonary bypass represent the period of highest risk for decompensation. The continuous monitoring of CO2 production is suggested as a useful clinical method to detect postoperative changes in metabolic rate.