Adrenergic Receptor Genotype but Not Perioperative Bisoprolol Therapy May Determine Cardiovascular Outcome in At-risk Patients Undergoing Surgery with Spinal Block: The Swiss Beta Blocker in Spinal Anesthesia (BBSA) Study: A Double-blinded, Placebo-controlled, Multicenter Trial with 1-Year Follow-up

Background: Neuraxial blockade is used as primary anesthetic technique in one third of surgical procedures. The authors tested whether bisoprolol would protect patients at risk for cardiovascular complications undergoing surgery with spinal block.

Methods: The authors performed a double-blinded, placebo-controlled, multicenter trial to compare the effect of bisoprolol with that of placebo on 1-yr composite outcome including cardiovascular mortality, nonfatal myocardial infarction, unstable angina, congestive heart failure, and cerebrovascular insult. Bisoprolol was given orally before and after surgery for a maximum of 10 days. Adrenergic receptor polymorphisms and safety outcome measures of bisoprolol therapy were also determined.

Results: A total of 224 patients were enrolled. Spinal block could not be established in 5 patients. One hundred ten patients were assigned to the bisoprolol group, and 109 patients were assigned to the placebo group. The mean duration of treatment was 4.9 days in the bisoprolol group and 5.1 days in the placebo group. Bisoprolol therapy reduced mean heart rate by 10 beats/min. The primary outcome was identical between treatment groups and occurred in 25 patients (22.7%) in the bisoprolol group and 24 patients (22.0%) in the placebo group during the 1-yr follow-up (hazard ratio, 0.97; 95% confidence interval, 0.55-1.69; P = 0.90). However, carriers of at least one Gly allele of the [beta]1-adrenergic receptor polymorphism Arg389Gly showed a higher number of adverse events than Arg homozygous (32.4% vs. 18.7%; hazard ratio, 1.87; 95% confidence interval, 1.04-3.35; P = 0.04).     

The 6-min walking distance: long-term follow up in patients with COPD.

The 6-min walking distance (6MWD) test is used in clinical practice and research into patients with chronic obstructive pulmonary disease (COPD). However, little is known about natural long-term change in this parameter. The 6MWD was measured at baseline and then annually for 5 yrs in 294 patients with COPD and its annual rate of decline was determined. Forced expiratory volume in one second (FEV1) was also measured and the relationship between changes in both markers was explored. At baseline, the median 6MWD was 380 m (range 160-600 m). It declined by 19% (16 m.yr(-1)) over the 5 yrs compared with baseline in patients with American Thoracic Society/European Respiratory Society stage III COPD (FEV1 30-50% predicted) and by 26% (15 m.yr(-1)) in patients with stage IV COPD (FEV1 <30% pred). Over the 5-yr follow-up, the proportion of patients with a minimal clinically significant decline of 54 m increased with the severity of the disease. It was 24% in stage II, 45% in stage III, and 63% in stage IV disease. In contrast, the rate of decline of FEV1 was greater in patients with milder airflow obstruction and lesser in patients with lower absolute FEV1 values. In conclusion, the 6-min walking distance test provides increasingly useful information as the severity of chronic obstructive pulmonary disease increases.     

No major effect of orciprenaline and propranolol upon ACTH-induced cortisol secretion.

Preclinical research suggests adrenal beta-adrenergic receptors to be involved in the regulation of steroid synthesis. In a group of healthy male volunteers, we compared ACTH-induced cortisol and dehydroepiandrosterone (DHEA) secretion after pre-treatment with orciprenaline, propranolol or placebo. Neither baseline nor ACTH-induced steroid secretion differed between these conditions. Our data do not support the hypothesis that the adrenal beta-receptor plays a major role in steroid secretion in humans.     

The rise in caesarean birth rate in Sagamu, Nigeria: reflection of changes in obstetric practice.

A retrospective and comparative study of women delivered by caesarean section over two different 3-year periods was conducted at Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria. The caesarean section rate (CSR) increased from 10.3% in 1989-1991 to 23.1% in 2000-2003. The most frequent indication in both periods was different: prolonged/obstructed labour (20.0%) in 1989-1991 and antepartum haemorrhage (14.9%) in 2000-2003. Malpresentation, antepartum haemorrhage and pre-eclampsia/eclampsia were responsible for 51.7% of the difference in the CSR recorded between both periods. The CSR rose from 13.3% to 25.0% while the instrumental vaginal delivery (IVD) rate decreased significantly by 11.4% among the nulliparous women between the periods. Increase in CSR can be attributed mainly to reduction in IVD rate and alteration in the management of labour complications and induction policy. Strategies to reduce the CSR should cut across all indications and focus on encouraging instrumental vaginal deliveries, especially among nulliparous women.     

Neuronal regeneration after application of radiofrequency energy to collagenous tissue is affected by limb immobilization: an in vivo animal study.

Despite widespread use of radiofrequency (RF)-shrinkage, there have been no studies on the influence of RF-energy on neural elements of collagenous tissue. The purpose of this study was to examine the effect of RF-shrinkage on neural structures of capsuloligamentous tissue and the recovery of neural elements under different postoperative treatment protocols. One patellar tendon of 46 New-Zealand-White rabbits was shrunk. Six rabbits were sacrificed immediately postoperative. Twenty rabbits were not immobilized, 10 were immobilized for 3 and 10 were immobilized for 6 weeks. A monoclonal antibody, specific against a neurofilament protein, was used to detect nerves and neural structures. Staining pattern of nerve fibres was significantly altered immediately postoperative. After 3 weeks the number of nerve fibres and bundles decreased significantly in immobilized and non-immobilized limbs. The loss of nerve fibres was significantly less in immobilized limbs. At 6 weeks the number of neural elements in immobilized limbs increased to the level of untreated control tissue. In non-immobilized limbs we found no recovery of neural elements 9 weeks postoperatively. At this time the number of nerve fibres and bundles was still significantly less compared to the untreated control limbs. RF-shrinkage causes significant alteration of neural elements. Under immobilization nerve fibres and bundles reach the level of normal untreated tissue. Careful rehabilitation is important after RF-shrinkage. Not only for biomechanical reasons, but also to allow the neural elements to recover, thermally modified tissue should be protected from normal physiologic loads.