Mk Akama

Hyperbaric oxygen therapy accelerates neurologic recovery after 15-minute complete global cerebral ischemia in dogs

Background and MethodsAlthough hyperbaric oxygen therapy is clinically used for the treatment of several types of ischemic brain injury, few basic animal studies are available that provide a rationale for this therapy for complete global brain ischemia. Therefore, we investigated the effect of hyperbaric oxygen therapy on neurologic recovery after 15-min complete global cerebral ischemia in a canine model. Complete global ischemia was induced in 19 dogs by occlusion of the ascending aorta and the caval veins. Nine dogs were randomized to treatment with hyperbaric oxygenation (3 atmospheres absolute, 100% oxygen for 1 hr) at 3, 24, and 29 hrs after ischemia under spontaneous respiration, while the other ten dogs served as the control group without hyperbaric oxygen therapy (group C). Neurologic recovery was evaluated based on the electroencephalogram (EEC) activity score (1 = normal; 5 = isoelectric) and the neurologic recovery score (100 = normal; 0 = brain death) over a 14-day postischemic period. ResultsThe survival rates were 3/10 (30%) in the control group vs. 7/9 (78%) in the group treated with hyperbaric oxygen (p < .05). Over the 14-day postischemic period, the best (lowest) EEG scores of each dog were significantly (1.7 ± 0.2 vs. 2.9 ± 0.3; mean ± SE, p < .01) lower in the hyperbaric oxygen-treated group. The best neurologic recovery scores of each dog were significantly (69 ± 6 vs. 48 ± 5; mean ± SE, p < .05) higher in the treated animals. The number of dogs that recovered to a neurologic recovery score of >65 (assessed as a slight disability) were 1/10 in the control group and 6/9 in the group treated with hyperbaric oxygen (p < .02). ConclusionsHyperbaric oxygen therapy performed in the early postischemic period accelerated neurologic recovery and improved the survival rate in dogs after 15-mins of complete global cerebral ischemia.

Elevated plasma levels of interleukin-6, interleukin-8, and granulocyte colony-stimulating factor during and after major abdominal surgery

STUDY OBJECTIVE To evaluate the influence of major abdominal surgery on the plasma levels of inflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8) and granulocyte colony-stimulating factor (G-CSF). DESIGN Prospective study. SETTING University hospital. PATIENTS 10 ASA physical status I and II patients undergoing upper abdominal surgery. INTERVENTIONS All patients received combined general-epidural anesthesia with isoflurane and nitrous oxide, after insertion of an epidural catheter at T7-T9 dosed with 1.5% lidocaine. MEASUREMENTS AND MAIN RESULTS Plasma cytokine (IL-6, IL-8, G-CSF) levels were determined with an enzyme-linked immunosorbent assay (ELISA) at pre-anesthesia, 0, 2, and 4 hours during surgery, and at the end of surgery, followed by sampling on the morning of postoperative days 1 (POD1) and 3 (POD3). Plasma cortisol levels were also determined. The plasma levels of IL-6 increased gradually after skin incision and reached the maximal value at the end of surgery (p < 0.001). IL-8 levels also increased from the baseline value to their maximum at the end of surgery (p < 0.05). G-CSF levels were elevated from the pre-anesthesia value to their maximum by the end of operation (p < 0.005). Plasma cortisol levels were increased after skin incision (p < 0.001). Postoperative cytokine levels correlated significantly with each other (r = 0.68, p < 0.05 for IL-6 vs. IL-8; r = 0.81, p < 0.005 for IL-6 vs. G-CSF; and r = 0.84, p < 0.005 for IL-8 vs. G-CSF). Postoperative IL-6 levels and intraoperative blood loss correlated significantly (r = 0.64, p < 0.05). CONCLUSIONS These results suggest that major upper abdominal surgery stimulates the release of inflammatory cytokines presumably from the operation site. Further study is warranted to evaluate the modulation of inflammatory responses in the perioperative period.

Administration of MgSO4 failed to improve the neurological recovery after complete global brain ischemia in dogs

The cerebral protective effects of MgSO4 after complete global brain ischemia were evaluated with EEG, evoked potentials (EP) and the neurological recovery score (NRS) in the dog. Complete global brain ischemia for 15 min was achieved by occluding the ascending aorta and the caval veins. The MgSO4 group (N=7) were injected with a 10% MgSO4 solution and the control group (N=7) were administered a normal saline intravenously from the beginning of the resuscitation to 48 h after ischemia. The EEG grades (1=normal, 5=flat) in the control group and the MgSO4 group were 3.9±0.1 (mean ±SEM) and 3.7±0.3, and the EEG-EP scores (6=normal, 0=serious deterioration) were 2.6±0.4 and 2.7±0.4 4h after ischemia, respectively. The 7-day survival rates for ischemia were equal in both groups (5/7:71%). The NRSs (0=death, 100=normal) in the control group and the MgSO4 group were 50±3 (n=7) and 43±9 (n=7) on the 3rd day after ischemia, and were 56±5 (n=5) and 42±12 (n=5) on the 7th day. The differences between the two groups were not significant. We conclude that MgSO4 administered after ischemia has no beneficial effects on the recovery of EEG, EP and the NRS after 15 min of complete global brain ischemia in the dog.