Effects of transients in LIGO suspensions on searches for gravitational waves.

This paper presents an analysis of the transient behavior of the Advanced LIGO (Laser Interferometer Gravitational-wave Observatory) suspensions used to seismically isolate the optics. We have characterized the transients in the longitudinal motion of the quadruple suspensions during Advanced LIGO's first observing run. Propagation of transients between stages is consistent with modeled transfer functions, such that transient motion originating at the top of the suspension chain is significantly reduced in amplitude at the test mass. We find that there are transients seen by the longitudinal motion monitors of quadruple suspensions, but they are not significantly correlated with transient motion above the noise floor in the gravitational wave strain data, and therefore do not present a dominant source of background noise in the searches for transient gravitational wave signals. Using the suspension transfer functions, we compared the transients in a week of gravitational wave strain data with transients from a quadruple suspension. Of the strain transients between 10 and 60 Hz, 84% are loud enough that they would have appeared above the sensor noise in the top stage quadruple suspension monitors if they had originated at that stage at the same frequencies. We find no significant temporal correlation with the suspension transients in that stage, so we can rule out suspension motion originating at the top stage as the cause of those transients. However, only 3.2% of the gravitational wave strain transients are loud enough that they would have been seen by the second stage suspension sensors, and none of them are above the sensor noise levels of the penultimate stage. Therefore, we cannot eliminate the possibility of transient noise in the detectors originating in the intermediate stages of the suspension below the sensing noise.

Survey of the practice of epidural analgesia in a regional sample of obstetric units.

An investigation into practices of the epidural services in a regional sample of obstetric units was undertaken following recent reported disasters associated with epidural analgesia for labour pain. A questionnaire was completed by all 22 obstetric units in the region, which included six teaching, 14 district and two independent centres. In three units the epidural service was shared with the obstetricians. A continuous anaesthetic presence was provided in 16 of 22 units. There was considerable variation in the attendance upon epidural patients by the anaesthetists. Instructions to midwives for top-ups and subsequent care of patients followed no uniform pattern. Midwife in-service training in the initial management of serious epidural complications and in cardiopulmonary resuscitation was inconsistent. In some units, the avoidance of aortocaval compression was not emphasised in the management of serious complications such as severe maternal hypotension, total spinal blockade or cardiac arrest of the parturient. The results obtained in this survey suggest that there is a need to review the requirements in the provision of obstetric epidural services and consideration should be given to the establishment of a generally accepted standard of practice.

A randomised controlled trial of the effect of regional nerve blocks on immediate post-tonsillectomy pain in adult patients.

Post-operative pain is the main cause of morbidity following tonsillectomy. The efficacy of glossopharyngeal and lesser palatine nerve blocks in controlling postoperative pain in adult patients was investigated prospectively. Patients 16 years and older admitted for elective tonsillectomy were randomised to one of three groups to receive a pre-incisional oropharyngeal injection of 0.5% bupivicaine, a 'dummy' injection of saline or no injection. Dissection tonsillectomy and general anaesthetic techniques were standardized. Postoperative pain was monitored for 24 h. ANOVA, chi2 and Fisher's exact test were used for intergroup comparisons. Ninety-two patients (72 women and 20 men), mean age 22 years were studied. Twenty-nine patients received 0.5% bupivicaine, 30 saline and 33 no pre-incisional injection. The overall mean pain scores of 2.1, 1.9 and 1.9 in the bupivicaine, saline and no injection groups were similar. Glossopharyngeal and lesser palatine 0.5% bupivicaine nerve blocks are not effective in reducing early post-tonsillectomy pain.

Continuous infusion epidural analgesia in obstetrics. A comparison of 0.08% and 0.25% bupivacaine.

The effects of 0.08% (Group A) and 0.25% (Group B) solutions of bupivacaine were compared in a random manner, to assess continuous pump infusion epidural analgesia in labour. Both solutions were infused at a dose rate of 20 mg bupivacaine/hour. The results in all the mothers who had received infusions lasting more than 4 hours were studied. There were 25 in Group A and 28 in Group B. Any treatment during the infusion epidural for inadequate analgesia, hypotension, etc., was recorded as an intervention. The mean of the intervention-free intervals was significantly greater in Group A than in Group B, and significantly fewer top-up injections were required in Group A. The results show that the administration of a 0.08% solution of bupivacaine into the epidural space by continuous pump infusion is more labour saving than the infusion of a 0.25% solution. The concept that a greater volume infusion rate maintains a more extended liquid sleeve of local anaesthetic in the epidural space is supported.

The loading dose for continuous infusion epidural analgesia. A technique to reduce the incidence of hypotension.

The effects of 0.08% and 0.5% bupivacaine, given in equal volumes as the loading dose prior to continuous infusion epidural analgesia, were compared. The incidence of hypotension, as well as the height of sensory blockade, was markedly lowered by reducing the loading dose of bupivacaine. However, the efficacy of the epidural analgesia was maintained by using the same volume for the loading dose. The mean onset of analgesia was delayed from 9.1 to 13.6 minutes. There were fewer calls for intervention consequent upon the reduction in adverse effects. The use of 8 ml 0.08% bupivacaine for the loading dose or for subsequent top-ups is recommended. The concept of a liquid sleeve of local anaesthetic in the epidural space is further supported.

Glycopyrronium requirements for antagonism of the muscarinic side effects of edrophonium.

We have compared, in 60 adult patients, the cardiovascular effects of glycopyrronium 5 micrograms kg-1 and 10 micrograms kg-1 given either simultaneously or 1 min before edrophonium 1 mg kg-1. Significant differences between the four groups were detected (P less than 0.001). Both groups receiving 10 micrograms kg-1 showed increases in heart rate of up to 30 beat min-1 (95% confidence limits 28-32 beat min-1). Use of glycopyrronium 5 micrograms kg-1 provided greater cardiovascular stability and, given 1 min before the edrophonium, was sufficient to minimize early, edrophonium-induced bradycardias. This low dose of glycopyrronium provided good control of oropharyngeal secretions.