Hyperglycaemia emerging during general anaesthesia induces rat acute kidney injury via impaired microcirculation, augmented apoptosis and inhibited cell proliferation.

AIM: Major surgery under general anaesthesia frequently triggers acute kidney injury by yet unknown mechanisms. We investigated the role of anaesthesia-triggered systemic hyperglycaemia in impairment of renal functioning, renal tissue injury, intra-renal Angiotensin-II synthesis and endogenous insulin production in anaesthetized rats. METHODS: Eighty-eight Sprague-Dawley rats underwent general anaesthesia for 1 h by different anaesthetic compounds. Some of the animals were either injected with high glucose, or received insulin prior to anaesthesia. Blood pressure, renal functioning estimated by cystatin-C and urea, renal perfusion evaluated by laser Doppler technique, blood glucose and insulin were surveyed. Subsequently, rat kidneys were excised, to be used for immunohistochemical examinations or preparation of renal extracts for intra-renal Angiotensin-II measurements. RESULTS: Elevated blood sugar was observed 5 min following induction of anaesthesia, concurrently with deterioration of renal functioning, drop of systemic blood pressure and decreased renal blood flow. Blood insulin concentrations positively correlated with glucose levels. Intra-renal Angiotensin-II was significantly augmented. Immunohistochemical examinations demonstrated enhanced staining for pro-apoptotic proteins and negligible cell proliferation in tubular tissues. Renal damage resultant from anaesthesia-induced hyperglycaemia could be attenuated by insulin injections. Rats challenged with glucose prior to anaesthesia demonstrated cumulative hyperglycaemia, further increase in insulin secretion, drop of renal blood flow and increased apoptosis. The effects were specific, since they could not be mimicked by replacing glucose with mannose. CONCLUSION: Anaesthesia-induced hyperglycaemia affects intra-renal auto-regulation via decreased renal perfusion, thus triggering renal function deterioration and tubular injury. Increased intra-renal Angiotensin-II aggravates the damage. Tight hypoglycaemic control might prevent or, at least, attenuate anaesthesia-induced renal injury.

Hyperglycaemia, inflammation, RAS activation: three culprits to blame for acute kidney injury emerging in healthy rats during general anaesthesia.

AIM: Major surgery under general anaesthesia might evoke acute kidney injury (AKI), sometimes culminating in end stage renal disease. We investigated the roles of hyperglycaemia, inflammation and renin-angiotensin system (RAS) activation in induction of AKI following anaesthesia by different anaesthetic drugs and/or regimens. METHODS: Ninety-four Sprague-Dawley rats underwent 1 h-anaesthesia by various protocols, including repeated blood glucose and insulin measurements. Blood samples and kidneys were allocated at sacrifice, for evaluation of renal function, inflammatory status and Angiotensin-II availability. RESULTS: Hyperglycaemia emerged in unconscious rats irrespective of anaesthetic drug choice or anaesthesia regimen. Insulin increase correlated with hyperglycaemia levels. Levels of Cystatin-C, as well as serum and urine neutrophil gelatinase-associated lipocain (NGAL), were significantly augmented. Serum transforming growth factor beta (TGF-ß) and interleukins (IL)-1ß, -4, -6, and -10 were significantly increased. Intra-renal Angiotensin-II, TGF-ß, IL-6 and-10 were significantly increased. IL-1 was decreased. IL-4 remained unaltered. CONCLUSIONS: Acute hyperglycaemia, systemic and intra-renal inflammation and RAS activation were independently triggered by induction of anaesthesia. Each confounder aggravated the impacts of the others, bringing about concomitant deterioration of renal function. Increased insulin secretion attenuated but did not abolish hyperglycaemia. Systemic inflammation was counterforced by anti-inflammatory cytokines, whereas intra-renal inflammation persisted, so that AKI progressed unopposed.

Accidental venous and dural puncture during epidural analgesia in obese parturients (BMI > 40 kg/m2): three different body positions during insertion.

STUDY OBJECTIVE: To assess the frequency of blood vessel punctures in morbidly obese parturients [body mass index (BMI) > 40 kg/m(2)] during epidural catheterization, in three different body positions. DESIGN: Prospective, randomized study. SETTING: Delivery room of a university-affiliated hospital. PATIENTS: 347 obese parturients (BMI > 40 kg/m(2)) undergoing continuous epidural analgesia during labor. INTERVENTIONS: Patients were randomized to undergo epidural catheterization in the sitting, lateral recumbent horizontal, or lateral recumbent head-down positions. MEASUREMENTS AND MAIN RESULTS: A lower frequency of epidural venous cannulation was noted when this procedure was performed in the lateral recumbent head-down position (4.8%) than in the lateral recumbent horizontal (11.6%) or sitting position (18.3%) (P = 0.001). Frequency of accidental subarachnoid puncture did not differ significantly (2.5%, 2.6%, and 3.7%), respectively. CONCLUSION: Adoption of the lateral recumbent head-down position for the performance of lumbar epidural blockade in labor at term reduces the frequency of lumbar epidural venous puncture in obese parturients (BMI > 40 kg/m(2)).

Total cell associated electrolyte homeostasis in rat spinal cord cells following apparently irreversible injury.

BACKGROUND: We investigated total electrolyte homeostasis in spinal cord cells of rats subjected to irreversible spinal cord trauma. MATERIAL/METHODS: Forty-two rats underwent total transection of spinal cord (Group 1); chemical neurolysis by 10% lidocaine overdose (Group 2); sham "injury" (Group 3). Spinal cords were isolated 24 h, 72 h or 7 days following injury. Total cellular Ca, Mg, Na and K were measured in the spinal cord thoracic or lumbar parts using an atomic absorption spectrometer. RESULTS: Group 1: A significant Ca, Mg, Na, and K efflux was observed in thoracic and lumbar parts 24 h following transection. By 72 h, a significant re-entrance of Ca was evident. By 168 h, an influx of all electrolytes was demonstrable, sometimes reaching concentrations above the pre-trauma levels. Group 2: Following 24 h, Na, K, Ca, and Mg concentrations dropped significantly both in thoracic and lumbar parts. By 72 h, the electrolyte re-entrance was evident in the thoracic, but not the lumbar part. By 168 h, Na, K, Ca, and Mg influx was observed both in thoracic and lumbar parts, the concentration approaching pre-trauma levels. Group 3: No changes in electrolyte content were observed in spinal cords of sham-operated animals. CONCLUSIONS: Following massive, apparently irreversible injury of the spinal cord, some restorative processes do take place at the cellular level. Subsequent supernormal accumulation of intracellular electrolytes, especially Ca, might eventually contribute to a secondary injury. Should this be the case, pharmacotherapeutic intervention might prove beneficial.

The lateral recumbent head-down position decreases the incidence of epidural venous puncture during catheter insertion in obese parturients.

PURPOSE: The unintentional and unrecognized cannulation of an extradural vein is a potentially serious complication of an epidural anesthetic. The present study was undertaken to assess the incidence of blood vessel puncture related to epidural catheterization in three different body positions, in a cohort of morbidly obese parturients, following the completion of a similar study published in 2001 from which such parturients were excluded. METHODS: The study was conducted in 450 (three groups of 150) morbidly obese, obstetric patients undergoing continuous epidural analgesia during labour. Epidural catheterization was performed on patients randomized to the sitting, lateral recumbent horizontal, or lateral recumbent head-down position. RESULTS: There was a lower incidence of vessel cannulation when this procedure was performed in the lateral recumbent head-down position [1.3%; body mass index (BMI): 37.0] than in the lateral recumbent horizontal [12.9%; BMI: 38.0] and in the sitting position [12.0%; BMI: 38.0]. The incidence of accidental subarachnoid puncture was 2%, 1.3% and 2% respectively, in these same positions. CONCLUSION: Adoption of the lateral recumbent head-down position for the performance of lumbar epidural blockade, in labour at term, reduces the incidence of lumbar epidural venous puncture in these obese parturients.