Bedside interpretation of simplified continuous EEG after cardiac arrest.

BACKGROUND: Continuous EEG-monitoring (cEEG) in the ICU is recommended to assess prognosis and detect seizures after cardiac arrest but implementation is often limited by the lack of EEG-technicians and experts. The aim of the study was to assess ICU physicians ability to perform preliminary interpretations of a simplified cEEG in the post cardiac arrest setting. METHODS: Five ICU physicians received training in interpretation of simplified cEEG - total training duration 1 day. The ICU physicians then interpreted 71 simplified cEEG recordings from 37 comatose survivors of cardiac arrest. The cEEG included amplitude-integrated EEG trends and two channels with original EEG-signals. Basic EEG background patterns and presence of epileptiform discharges or seizure activity were assessed on 5-grade rank-ordered scales based on standardized EEG terminology. An EEG-expert was used as reference. RESULTS: There was substantial agreement (κ 0.69) for EEG background patterns and moderate agreement (κ 0.43) for epileptiform discharges between ICU physicians and the EEG-expert. Sensitivity for detecting seizure activity by ICU physicians was limited (50%), but with high specificity (87%). CONCLUSIONS: After cardiac arrest, preliminary bedside interpretations of simplified cEEGs by trained ICU physicians may allow earlier detection of clinically relevant cEEG changes, prompting changes in patient management as well as additional evaluation by an EEG-expert. This strategy requires awareness of limitations of both the simplified electrode montage and the cEEG interpretations performed by ICU physicians. cEEG evaluation by an expert should not be delayed.

Glucose as a marker of fluid absorption in bipolar transurethral surgery.

BACKGROUND: Historically, a reduced serum sodium concentration has been used to diagnose absorption of electrolyte-free irrigating fluid during transurethral resection of the prostate (TURP). In bipolar TURP, the irrigating solution contains electrolytes, thus invalidating the serum sodium method. In this study, we investigated whether glucose can be used to diagnose the absorption of irrigating fluid during TURP procedures. METHODS: The serum glucose and sodium concentrations were measured in 250 patients undergoing monopolar TURP using either 1.5% glycine or 5% glucose for urinary bladder irrigation. The glucose kinetics was analyzed in 10 volunteers receiving a 30-min infusion of 20 mL/kg of acetated Ringer's solution with 1% glucose. These data were then used in computer simulations of different absorption patterns that were summarized in a nomogram for the relationship between the glucose level and administered fluid volume. RESULTS: There was a statistically significant inverse linear relationship between the decrease in serum sodium and the increase in glucose levels after absorption of 5% glucose during TURP (r(2) = 0.80). The glucose concentration increased, from 4.6 (sd 0.4) to 8.3 (0.9) mmol/L, during the experimental infusions. Regardless of the absorption pattern, all simulations indicated that the uptake of 1 L of fluid containing 1% glucose corresponded to an increase in the glucose level of 3.7 (sd 1.6) mmol/L at the end of surgery, whereas 2 L yielded an increase of 6.9 (1.7) mmol/L. CONCLUSIONS: In bipolar TURP, the addition of glucose to a concentration of 1% in the electrolyte-containing irrigation fluid can be used as a tracer of absorption that is comparable with measuring serum sodium after monopolar TURP.

Tranexamic acid does not prevent rebleeding in an uncontrolled hemorrhage porcine model.

BACKGROUND: Fluid resuscitation after uncontrolled hemorrhage might promote rebleeding and irreversible shock. Tranexamic acid is a procoagulant drug that limits blood loss after surgery of the hip, knee, and heart. We hypothesized that pretreatment with tranexamic acid reduces the rebleeding in uncontrolled hemorrhage and thereby allows safe administration of crystalloid fluid resuscitation. METHODS: A 120-minute intravenous infusion of 100 mL/kg of Ringer's solution was given to 24 pigs (mean weight, 20 kg) 10 minutes after lacerating the infrarenal aorta. The animals were randomized to receive an intravenous injection of 15 mg/kg of tranexamic acid or placebo just before starting the resuscitation. Rebleeding events were monitored by two ultrasonic probes positioned proximal and distal to the laceration. RESULTS: Tranexamic acid had no effect on the number of rebleeding events, bled volume, or mortality. The initial bleeding stopped within 4 minutes after the injury. The five animals that died suffered from 4.4 rebleeding events on average, which tripled the total blood loss, whereas the survivors had only 1.3 such events during fluid resuscitation (p < 0.02). At autopsy, death was associated with a larger total hemorrhage; the blood recovered from the abdomen weighed 1.4 kg (median) in nonsurvivors and 0.6 kg in survivors (p < 0.001), with the difference being attributable to rebleeding. CONCLUSION: Rebleeding events increased the amount of blood lost and the mortality in uncontrolled aortic hemorrhage. Tranexamic acid offered no benefit.