Effects of remifentanil-based general anaesthesia with propofol or sevoflurane on muscle microcirculation as assessed by near-infrared spectroscopy.
BACKGROUND
Although anaesthetics are known to alter microcirculation no study has, to our knowledge, documented changes in human skeletal microcirculatory function during general anaesthesia.


METHODS
Forty-four patients undergoing maxillofacial surgery at a university hospital were prospectively randomized to receive general anaesthesia with remifentanil combined with propofol or sevoflurane. Muscle microcirculation was investigated with near-infrared spectroscopy (NIRS) before general anaesthesia was induced and 30 min later. An NIRS device (NIMO, Nirox) was used to quantify calf deoxyhaemoglobin [HHb], oxyhaemoglobin [HbO2], and total haemoglobin [HbT] concentrations, coupled to a series of venous and arterial occlusions to measure calf blood flow, muscle oxygen consumption, calf vascular resistance, microvascular compliance, and haemoglobin resaturation rate (RR).


RESULTS
In both the groups, general anaesthesia induced marked changes in muscle microcirculation: the tissue blood volume increased (+33% in remifentanil-sevoflurane and +45% with remifentanil-propofol groups), microvascular resistance decreased (-31% and -38%, respectively), and the post-ischaemic haemoglobin RR decreased (-48% and -36%, respectively). In the remifentanil-propofol group, the muscle blood flow increased (P<0.001), whereas in the remifentanil-sevoflurane group microvascular compliance and muscle oxygen consumption decreased (P<0.01).


CONCLUSIONS
Remifentanil-based general anaesthesia with propofol or sevoflurane altered the muscle microcirculation in different ways. Quantitative NIRS, a technique that takes into account the optical tissue properties of the individual subject, can effectively measure these changes non-invasively.
Department of Anaesthesiology and Intensive Care, University of Rome 'La Sapienza', Second Faculty of Medicine, Sant'Andrea Hospital, Rome, Italy. radbl@libero.it
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De Blasi
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Palmisani
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Boezi
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Arcioni
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Collini
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Troisi
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Pinto
D000293:Adolescent; D000328:Adult; D000368:Aged; D019162:Anesthetics, Combined / Q000494:pharmacology; D018681:Anesthetics, General / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology; D008833:Microcirculation / Q000187:drug effects; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D018482:Muscle, Skeletal / Q000098:blood supply*; D019647:Oral Surgical Procedures; D010101:Oxygen Consumption / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D015742:Propofol / Q000494:pharmacology; D011446:Prospective Studies; D000077208:Remifentanil; D000077149:Sevoflurane; D019265:Spectroscopy, Near-Infrared
D019162:Anesthetics, Combined; D018681:Anesthetics, General; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D010880:Piperidines; D000077149:Sevoflurane; D000077208:Remifentanil; D015742:Propofol