A pilot study of hyperoxemia on neurological injury, inflammation and oxidative stress

BACKGROUND

Normobaric hyperoxia is used to alleviate secondary brain ischaemia in patients with traumatic brain injury (TBI), but clinical evidence is limited and hyperoxia may cause adverse events.

METHODS

An open label, randomised controlled pilot study comparing blood concentrations of reactive oxygen species (ROS), interleukin 6 (IL-6) and neuron-specific enolase (NSE) between two different fractions of inspired oxygen in severe TBI patients on mechanical ventilation.

RESULTS

We enrolled 27 patients in the Fi O₂ 0.40 group and 38 in the Fi O₂ 0.70 group; 19 and 23 patients, respectively, completed biochemical analyses. In baseline, there were no differences between Fi O₂ 0.40 and Fi O₂ 0.70 groups, respectively, in ROS (64.8 nM [22.6-102.1] vs. 64.9 nM [26.8-96.3], P = 0.80), IL-6 (group 92.4 pg/ml [52.9-171.6] vs. 94.3 pg/ml [54.8-133.1], P = 0.52) or NSE (21.04 ug/l [14.0-30.7] vs. 17.8 ug/l [14.1-23.9], P = 0.35). ROS levels did not differ at Day 1 (24.2 nM [20.6-33.5] vs. 29.2 nM [22.7-69.2], P = 0.10) or at Day 2 (25.4 nM [21.7-37.4] vs. 47.3 nM [34.4-126.1], P = 0.95). IL-6 concentrations did not differ at Day 1 (112.7 pg/ml [65.9-168.9) vs. 83.9 pg/ml [51.8-144.3], P = 0.41) or at Day 3 (55.0 pg/ml [34.2-115.6] vs. 49.3 pg/ml [34.4-126.1], P = 0.95). NSE levels did not differ at Day 1 (15.9 ug/l [9.0-24.3] vs. 15.3 ug/l [12.2-26.3], P = 0.62). There were no differences between groups in the incidence of pulmonary complications.

CONCLUSION

Higher fraction of inspired oxygen did not increase blood concentrations of markers of oxidative stress, inflammation or neurological injury or the incidence of pulmonary complications in severe TBI patients on mechanical ventilation.

Does obesity complicate regional anesthesia and result in longer decision to delivery time for emergency cesarean section?

BACKGROUND

Maternal obesity can cause problems with anesthesia and surgery which may be reflected in emergency cesarean sections (CS) as an increased decision-to-delivery interval (DDI).

AIM

To study the association of elevated maternal BMI with DDI and the failure of regional anesthesia.

METHODS

Eight hundred and forty-two consecutive emergency CSs during a period of 1 year in a tertiary hospital were studied retrospectively. DDIs were analyzed in Crash and < 30-min urgency categories (n = 528), while the time required to establish regional anesthesia and its success were analyzed for all emergency CS cases.

RESULTS

The urgency distribution of the CSs was 11%, 52%, and 37% in Crash, < 30-min, and > 30-min urgency categories respectively. Increased BMI was associated with longer DDI time in the < 30-min urgency category (33(13-176) vs. 38(18-118) min; P < 0.05 for BMI < 30 and > 35 group respectively). Regional anesthesia failures (new regional anesthesia, conversion to general anesthesia, or complaint of pain during surgery) took place in 3.7%, 6.8%, and 8.5% in the BMI < 30, 30-35, and > 35 groups respectively (P = 0.021). Epidural top-up resulted in shorter DDI and time delay between arrival at the operating room and skin incision across all urgency and BMI groups than combined spinal epidural (CSE) anesthesia.

CONCLUSION

Higher BMI was associated with longer DDI and more regional anesthesia failures. Epidural top-up was faster than CSE for establishing CS anesthesia.

Outcome and resource utilization in gastroenterological surgery

BACKGROUND

A small minority of patients undergoing gastroenterological surgery are at high risk for postoperative complications, which may lead to prolonged hospital stay, disproportionate use of resources and increased mortality. The nature and frequency of, and predictive factors for, postoperative complications were studied and the impact of complications on resource utilization was assessed.

METHODS

A prospective observational study was undertaken of 503 patients undergoing gastroenterological surgery in a tertiary care centre. The incidence of cardiorespiratory, infective and surgical complications was assessed. The need for reoperation, intensive care and length of hospital stay, readmission, death at 6 months and costs were evaluated.

RESULTS

Some 235 patients (47 per cent) had at least one complication, most commonly delayed oral intake (n = 70). Complications were associated with cardiovascular disease, prolonged operation, high Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity, and increased number of Shoemaker's criteria. The length of hospital stay of patients with complications was longer than that of those without complications (11 versus 6 days). Morbidity resulted in a twofold increase in median costs.

CONCLUSION

High-risk patients could be identified by simple clinical criteria, although the commonly used risk criteria were not very sensitive. A reduction in postoperative complication rates would result in marked cost savings.

The duration of action of bupivacaine, levobupivacaine, ropivacaine and pethidine in peripheral nerve block in the rat

BACKGROUND

There is a current interest in local anaesthetic drugs/formulations exhibiting long durations of sensory block and minor motor-blocking effects.

OBJECTIVES

To compare the duration of sensory and motor blockade in peripheral nerve blocks induced by the new agents ropivacaine and levobupivacaine, with that of racemic bupivacaine and pethidine.

METHODS

Groups of 8 male Sprague-Dawley rats were subjected to infraorbital (IONB) or sciatic nerve block (SNB) employing 0.2 ml of differently concentrated solutions of bupivacaine, levobupivacaine, ropivacaine or pethidine. The sensory blocking effect in IONB is expressed as (i) the time to elicitation of an abdominal jerk by electrical stimulation at arbitrarily chosen (threshold) intensities (IONB degree 3, 5, 8 and 10), and as (ii) the area under the curve (AUC, threshold intensities vs time). The duration of motor block in SNB is given as the time from injection to regained ability to walk and grip normally with the toes. Comparisons of the dose-effect relationships for the investigated agents were made by analysis of covariance.

RESULTS

In IONB the log (dose)-log (effect) lines for bupivacaine, levobupivacaine and ropivacaine did not deviate from parallelism. The duration of sensory block induced by equimolar doses of these agents was similar, although bupivacaine exerted more pronounced effects than levobupivacaine (AUC by 25%, P=0.001; IONB degree 3 by 14%, P=0.03). In SNB only the log (dose)-log (duration) lines for bupivacaine vs levobupivacaine were found not to deviate from parallelism, both agents exerting similar durations of action. The motor-blocking effects of ropivacaine showed an inverse dose-duration relationship (P=0.019).

CONCLUSIONS

Equimolar doses of the investigated local anaesthetics exerted similar durations of sensory blockade in a peripheral nerve block model in the rat.