BACKGOUND: When ischemia reduces blood supply, hypothermia remains the sine qua non for reducing demand. An alternative to whole body deep hypothermia is an isolated cerebral hypothermia via perfusion of cooled blood through one internal carotid artery. The goal of this study was to evaluate the effect of isolated cold hemisphere perfusion during the cerebral ischemia on the formation of brain edema. METHODS: The studies were designed to perfuse a saline solution into both carotid arteries with a different temperature (left 15degreesC, right 38degreesC) in the same animal. Cerebral ischemia was produced by a combination of the both carotid artery saline perfusion and systemic hypotension to a mean arterial blood pressure of 40 mmHg for 10 minutes. Ninety minutes after reperfusion, brain water contents were measured using the kerosene/bromobenzene density gradient and compared with warm saline perfusion and normal control group. RESULTS: Brain water content of cold saline perfusion hemisphere measured at 90 minutes after ischemia showed decreased water content compared to warm saline perfusion hemisphere (p<0.05). CONCLUSIONS: Cerebral cold saline perfusion during the ischemia decreased the formation of brain edema. These results showed hypothemia is one of the most effective ways to protect brain from the ischemia.
Animals ; Arterial Pressure ; Brain Edema* ; Brain Ischemia ; Brain* ; Carotid Arteries ; Carotid Artery, Internal ; Edema ; Hypotension ; Hypothermia* ; Ischemia* ; Perfusion ; Reperfusion ; Sodium Chloride

BACKGROUND: Tourniquet hypertension (TH) may develop from an autonomic reflex consequent to the sensitization of the central nervous system (CNS) due to ischemia of the affected limb and noxious surgical stimulation. TH could be preventable when anesthetic depth is sufficient enough to block plastic changes of the CNS during an operation. This study was aimed to evaluate the efficacy of the bispectral index (BIS) to predict development of TH by assessing correlations between BIS changes and hemodynamic changes during the skin incision. METHODS: Sixty patients who had undergone a total knee arthroplasty with a pneumatic tourniquet during isoflurane anesthesia were selected, and the samples were randomly divided into two groups: BIS 30 (30 - 39) and BIS 40 (40 - 49). Several variables such as BIS, mean arterial pressure (MAP), heart rate (HR) and end tidal concentraion of isoflurane were monitored during the operation. TH was defined as more than a 30% increase in MAP compared with the baseline values during the skin incision. The correlation between BIS changes and MAP and HR changes, and the incidence of TH between BIS groups were compared. RESULTS: The MAP and HR were meaningfully increased in both the BIS 30 and the BIS 40 groups (P < 0.05), but no significant correlations were found between the BIS changes and the MAP and HR changes during the skin incision. The incidence of intraoperative hypertension was not different between the BIS groups. The BIS of the patients who had TH was not different from those who did not have TH. CONCLUSIONS: BIS may not reflect the changes of the CNS and autonomic nervous system induced by noxious surgical stimulation during an operation, and BIS changes during a skin incision cannot be a predictor of TH.
Anesthesia ; Arterial Pressure ; Arthroplasty* ; Autonomic Nervous System ; Central Nervous System ; Extremities ; Heart Rate ; Hemodynamics ; Humans ; Hypertension* ; Incidence ; Ischemia ; Isoflurane ; Knee* ; Plastics ; Reflex ; Skin ; Tourniquets*

BACKGROUND: Following musculoskeletal injuries, axons are exposed to tumor necrosis factor-alpha (TNF-alpha) and other inflammatory mediators. Exposure of axons to TNF-alpha and complete Freund's adjuvant (CFA) can cause hyperalgesia or allodynia in the distribution of the affected axons. The hypothesis that TNF-alpha, inflammatory mediators, and inflammation secondary to CFA activate nociceptor axons was tested using teased fiber techniques in the rat. METHODS: Electrophysiologic recordings were made from single nociceptors innervating both deep and cutaneous receptive fields (RF) supplied by the sciatic nerve. The axons proximal to the RF were exposed to either TNF-alpha, a mixture of inflammatory mediators (histamine, serotonin, bradykinin, and prostaglandin), or CFA. RESULTS: In a minority of nociceptors (15%), TNF-alpha rapidly evoked a response that was dose- dependent and transient. There was no difference between deep and cutaneous nociceptors in the incidence of TNF-alpha responses. The majority of neurons responded to TNF-alpha injected into their RFs. No neurons responded to axonal application of either the mixed inflammatory mediators or CFA. CONCLUSIONS: Our data supports that TNF-alpha can induce ectopic electrogenesis in nociceptor axons that innervate both deep and cutaneous tissues. This activity may correlate to the human perception of radicular pain that is often associated with neuritis.
Animals ; Axons* ; Bradykinin ; Freund's Adjuvant ; Humans ; Hyperalgesia ; Incidence ; Inflammation ; Neuritis ; Neurons ; Nociceptors ; Rats ; Sciatic Nerve ; Serotonin ; Tumor Necrosis Factor-alpha*

BACKGROUND: Caudal block has proved to be a satisfactory method of providing perioperative analgesia for pediatric surgery in inguinal and perineal areas. This study was designed to evaluate the effects of ketamine or clonidine as an adjunctive of caudal block produced by bupivacaine. METHODS: One hundred ninety five children aged 1~10 years, undergoing surgery in inguinal and perineal areas as ambulatory cases, were randomly allocated to one of four groups after the induction of general anesthesia; 0.25 % bupivacaine 1 ml/kg(group B), 0.25 % bupivacaine 1 ml/kg with ketamine 0.5 mg/kg(group K), 0.25 % bupivacaine 1 ml/kg with clonidine 1 microgram/kg(group C), and local infiltration group(group L). Postoperative pain was assessed using an objective pain scale and the incidence of side effects, such as urinary retention and nausea/vomiting was observed after surgery. RESULTS: In the group B and L, OPS score was higher and analgesics were more frequently administered than group K and C at the recovery room and at home after discharge(p<0.05). There was no difference between the groups in the incidence of nausea and vomiting but urinary retention at the recovery room was more frequent in group C than other groups(p<0.05). CONCLUSIONS: Caudal block provided more effective postoperative analgesia than local infiltration. In caudal block, the addition of ketamine or clonidine prolongs the duration of postoperative analgesia without significant increase in side effects.
Ambulatory Surgical Procedures* ; Analgesia* ; Analgesics ; Anesthesia, General ; Bupivacaine* ; Child ; Clonidine* ; Humans ; Incidence ; Ketamine* ; Nausea ; Pain, Postoperative ; Recovery Room ; Urinary Retention ; Vomiting