Minerva anestesiologica
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Minerva anestesiologica · Jun 1997
Arterial to end-tidal carbon dioxide gradient and physiological dead space monitoring during general anaesthesia: effects of patients' position.
One hundred and five ASA I-II patients, scheduled for elective surgical procedures were studied in order to evaluate the effect of different surgical postures on physiological pulmonary dead space (VDphys/ VT) and arterial to end-tidal carbon dioxide gradient [P(a-Et)CO2]. Patients were divided into four groups according to their position on the operating table: supine position (acting as control group, n = 33), 20 degree Trendelenburg position (n = 24), lateral position (n = 24) and prone position with convex saddle frame (n = 24). Physiologic dead space was measured using Enghoff modification of Bohr equation. Arterial CO2 partial pressure was measured by blood gas analysis and end tidal CO2 was measured by means of an infrared CO2 analyser. All measurements were performed 20 minutes after general anaesthesia induction, with patients mechanically ventilated by a constant inspiratory flow (TV = 8 ml kg-1, RR = 10-14, EIP = 10%) in order to reach a steady state end tidal CO2 ranging between 32 and 36 mmHg; afterwards surgery started. ⋯ In conclusion, the clinical practice of predicting PaCO2 from EtCO2 must be tempered by recognition of the potential magnitude of P(a-Et)CO2 gradient, which is higher than normal during general anaesthesia and further increased when positioning the patient other than supine.
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Minerva anestesiologica · Jun 1997
Review[Perioperative thermal homeostasis. A duty of the anesthesiologist].
Anaesthesia, surgical procedures and operating room temperature can deeply alter the human thermoregulatory system. Unexpected and sometimes serious perioperative complications can occur. Many studies have been carried out in order to describe and evaluate the detrimental effects produced by different anaesthesia procedures (whether by general, regional or integrated anaesthesia) on thermic homeostasis. ⋯ Italian anaesthetists have still a poor consideration about intraoperative body temperature monitoring and patients' warming as basic important skills for a better anaesthesiologic patients management. According with the literature, we do believe that this is not a right opinion. The purpose of the present paper would be to point out the most important knowledges concerning thermic homeostasis management, in order to increase anaesthesiologist's awareness in this essential field of patients perioperative care.