The risk of placenta accreta following primary elective caesarean delivery: a case-control study.

OBJECTIVE: To evaluate the risk of placenta praevia accreta following primary (first) elective or primary emergency caesarean section in a pregnancy complicated by placenta praevia. DESIGN: Retrospective matched case-control study, employing variable matching. SETTING: Tertiary referral centre between 1993 and 2008. POPULATION: Sixty-five cases and 102 controls were used for the analysis from a total of 82 667 births during the study period. METHODS: Relevant data were abstracted from clinical records. Matching of cases with controls was based on co-existing placenta praevia, number of previous caesarean sections, and age, with one or two controls per case. Results are presented as odds ratios (ORs) with 95% confidence intervals (95% CIs). MAIN OUTCOME MEASURES: Placenta accreta in a pregnancy complicated by placenta praevia following a primary elective or emergency caesarean section, and morbidity associated with pregnancies complicated by placenta accreta. RESULTS: Significantly more cases than controls had an elective caesarean section for their primary caesarean delivery (46.2 versus 18.6%; P < 0.001). There were no differences between groups for previous pregnancy loss, uterine surgery, and vaginal delivery, before or after the primary caesarean section. Compared with primary emergency caesarean section, primary elective caesarean section significantly increased the risk of placenta accreta in a subsequent pregnancy in the presence of placenta praevia (OR 3.00; 95% CI 1.47-6.12; P = 0.025). CONCLUSIONS: Our results suggest that women with a primary elective caesarean section without labour are more likely, compared with those undergoing primary emergency caesarean section with labour, to develop an accreta in a subsequent pregnancy with placenta praevia.

Equipment and strategies for emergency tracheal access in the adult patient.

The inability to maintain oxygenation by non-invasive means is one of the most pressing emergencies in anaesthesia and emergency care. To prevent hypoxic brain damage and death in a 'cannot intubate, cannot oxygenate' situation, emergency percutaneous airway access must be performed immediately. Even though this emergency is rare, every anaesthetist should be capable of performing an emergency percutaneous airway as the situation may arise unexpectedly. Clear knowledge of the anatomy and the insertion technique, and repeated skill training are essential to ensure completion of this procedure rapidly and successfully. Various techniques have been described for emergency oxygenation and several commercial emergency cricothyroidotomy sets are available. There is, however, no consensus on the best technique or device. As each has its limitations, it is recommended that all anaesthetists are skilled in more than one technique of emergency percutaneous airway. Avoiding delay in initiating rescue techniques is at least as important as choice of device in determining outcome.

Trends in joint arthroplasty litigation over five years: the British experience.

INTRODUCTION: Increasing numbers of joint arthroplasty are performed in Britain. While associated complications are well documented, it is not known which of those initiate malpractice claims. METHOD: A five-year period was assessed for trends to highlight areas for further improvement in patient information and surgical management. RESULTS: The National Health Service paid out almost £14 million for 598 claims. Forty per cent of this was for legal costs. The number of claims increased over time while the rate of successful claims decreased. CONCLUSIONS: A failure to consent adequately and to adhere to policies and standard practice can result in a successful malpractice claim. Protecting patients intraoperatively and maintaining high technical expertise while implementing policies and obtaining informed consent decreases the litigation burden.

Induction of labour in nulliparous women with an unfavourable cervix: a randomised controlled trial comparing double and single balloon catheters and PGE2 gel.

OBJECTIVE: To compare the efficacy and patient satisfaction of three methods of labour induction (double balloon catheters, single balloon catheters and prostaglandin gel) in term nulliparous women with unfavourable cervices. DESIGN: Randomised controlled trial. POPULATION: A total of 330 nulliparous women with unfavourable cervices induced at term. METHODS: Three cervical ripening study arms were used: double balloon catheter (107 women); 16F Foley catheter (110 women) and PGE(2) gel (2 mg) (113 women). MAIN OUTCOME MEASURES: Caesarean section, induction to delivery interval, adverse reactions and patient satisfaction. RESULTS: There was no difference in caesarean delivery rates between groups (double balloon 43%, single balloon 36%, PGE(2) 37%, P = 0.567). The induction to delivery interval was longer in the double balloon group (median 24.5; 95% CI 23.7, 30.6 hours) than the single balloon (23.2; 20.8, 25.8 hours) or PGE(2) (23.8; 21.7, 26.8 hours) (P = 0.043). Uterine hyperstimulation occurred in 14% of the PGE(2) group with none occurring with mechanical cervical ripening. Cord blood gases were worse in the PGE(2) group: median arterial pH double balloon 7.26 (range 7.03-7.40); single balloon 7.26 (7.05-7.44); PGE(2) 7.25 (6.91-7.41) (P = 0.050). Cervical ripening with the single balloon catheter was associated with significantly less pain (pain score > or =4: double balloon 55%, single balloon 36%, PGE(2) 63%, P < 0.001). CONCLUSIONS: Labour induction in nullipara with unfavourable cervices results in high caesarean delivery rates. Although all methods in this study had similar efficacy, the single balloon catheter offers the best combination of safety and patient comfort.

Manifestation of spin selection rules on the quantum tunneling of magnetization in a single-molecule magnet.

We present low temperature magnetometry measurements on a new Mn3 single-molecule magnet in which the quantum tunneling of magnetization (QTM) displays clear evidence for quantum mechanical selection rules. A QTM resonance appearing only at high temperatures demonstrates tunneling between excited states with spin projections differing by a multiple of three. This is dictated by the C3 molecular symmetry, which forbids pure tunneling from the lowest metastable state. Transverse field resonances are understood by correctly orienting the Jahn-Teller axes of the individual manganese ions and including transverse dipolar fields. These factors are likely to be important for QTM in all single-molecule magnets.

On-chip integration of high-frequency electron paramagnetic resonance spectroscopy and Hall-effect magnetometry.

A sensor that integrates high-sensitivity micro-Hall effect magnetometry and high-frequency electron paramagnetic resonance spectroscopy capabilities on a single semiconductor chip is presented. The Hall-effect magnetometer (HEM) was fabricated from a two-dimensional electron gas GaAsAlGaAs heterostructure in the form of a cross, with a 50 x 50 microm2 sensing area. A high-frequency microstrip resonator is coupled with two small gaps to a transmission line with a 50 Omega impedance. Different resonator lengths are used to obtain quasi-TEM fundamental resonant modes in the frequency range 10-30 GHz. The resonator is positioned on top of the active area of the HEM, where the magnetic field of the fundamental mode is largest, thus optimizing the conversion of microwave power into magnetic field at the sample position. The two gaps coupling the resonator and transmission lines are engineered differently--the gap to the microwave source is designed to optimize the loaded quality factor of the resonator (Q

High-frequency microstrip cross resonators for circular polarization electron paramagnetic resonance spectroscopy.

In this article we discuss the design and implementation of a novel microstrip resonator which allows absolute control of the microwaves polarization degree for frequencies up to 30 GHz. The sensor is composed of two half-wavelength microstrip line resonators, designed to match the 50 Omega impedance of the lines on a high dielectric constant GaAs substrate. The line resonators cross each other perpendicularly through their centers, forming a cross. Microstrip feed lines are coupled through small gaps to three arms of the cross to connect the resonator to the excitation ports. The control of the relative magnitude and phase between the two microwave stimuli at the input ports of each line allows for tuning the degree and type of polarization of the microwave excitation at the center of the cross resonator. The third (output) port is used to measure the transmitted signal, which is crucial to work at low temperatures, where reflections along lengthy coaxial lines mask the signal reflected by the resonator. Electron paramagnetic resonance spectra recorded at low temperature in an S=5/2 molecular magnet system show that 82% fidelity circular polarization of the microwaves is achieved over the central area of the resonator.

The Pentax-AWS((R)) rigid indirect video laryngoscope: clinical assessment of performance in 320 cases.

The Pentax-AWS airway scope system is a rigid indirect video laryngoscope with integrated tube guidance. Laryngoscopy and intubation are visualised using a built in LCD monitor which displays the view obtained by a CCD camera mounted in the tip of the laryngoscope. We describe its clinical performance in 320 patients. The Pentax-AWS significantly improved the laryngeal view compared to the Macintosh laryngoscope. Forty-six patients (14%) who were classified as Cormack Lehane glottic view grade 3 or 4 using the Macintosh laryngoscope were classified as grade 1 (45 cases) or 2a (1 case) using the Pentax-AWS airway scope. Laryngeal views measured by percentage of glottic opening score were improved significantly using the Pentax-AWS. Intubation using the Pentax-AWS was successful in all cases, 96% at the first and 4% at the second attempt. The mean (SD) time required to place the tracheal tube was 20 (10) s. The Cormack Lehane grade obtained with the Macintosh blade did not affect the total time to correctly position the tube using the Pentax-AWS. Intubation difficulty scale (score = 0 in 305 patients, score = 1 in 14 and score = 2 in one patient) indicates that tracheal intubation was performed easily in most cases. The Pentax-AWS not only improves the laryngeal view, but its tube guide also facilitates rapid, easy and reliable tracheal intubation under vision. It can be useful in routine anesthesia care and may be advantageous in the situation of unanticipated difficult intubation.

The Parker Flex-Tip tracheal tube makes endotracheal intubation with the Bullard laryngoscope easier and faster.

BACKGROUND: The Bullard laryngoscope can be useful in management of difficult airway. When the endotracheal tube is advanced over the original Bullard laryngoscope stylet, the endotracheal tube sometimes makes contact with structures around the vocal cords, especially the right arytenoids. A similar problem also occurs with flexible fibreoptic intubation and it has been shown that use of the Parker Flex-Tip tube usually resolves the problem. In this study we tested our hypothesis that use of the Parker Flex-Tip tube might improve endotracheal tube passage with the Bullard laryngoscope. METHODS: Forty patients scheduled for elective anaesthesia were randomly assigned into group ST (standard tube) or Group PT (Parker Flex-Tip tube). The time taken to achieve successful endotracheal tube placement after obtaining the best laryngeal view, the number of attempts at intubation and the incidences of successful intubation at first attempt and of re-direction of the Bullard laryngoscope during intubation were recorded. Unpaired t-test and chi2-test were employed and P < 0.05 was considered significant. RESULTS: Use of the Parker Flex-Tip tube reduced the time required for successful endotracheal tube placement after the best laryngeal view was obtained from 14 +/- 6 to 6 +/- 2 s (P < 0.01). It also reduced the incidence of requirement for re-direction of the Bullard laryngoscope during intubation from 10/19 to 1/19 (P < 0.01). The incidence of successful intubation at the first attempt (18/19 vs. 15/19) was higher in the PT group but the difference was not statistically significant. CONCLUSIONS: During intubation with the Bullard laryngoscope, use of the Parker Flex-Tip tube is associated with more rapid success and a lower incidence of re-direction of the Bullard laryngoscope during endotracheal intubation when compared to a standard endotracheal tube.

Perceptions of orthopaedic surgeons regarding hepatitis C viral transmission: a questionnaire survey.

INTRODUCTION: Occupationally acquired hepatitis C viral infection is an important issue in surgery since there are no known vaccines or effective prophylaxis. MATERIALS AND METHODS: An anonymous questionnaire survey was performed to determine the attitudes and perception of risks of occupational acquired hepatitis C viral transmission in orthopaedic surgeons. RESULTS: A total of 763 questionnaires were posted to orthopaedic surgeons with various subspecialty interests and 261 surgeons responded (34.2%). Of respondents, 117 (47%) had sustained sharps injuries in the previous 12 months. Only 82 surgeons (33%) always reported such injuries, although 208 (84%) expressed concerns of occupationally acquired hepatitis C viral transmission. Orthopaedic surgeons were mostly unaware of the true prevalence of hepatitis C in high-risk groups, such as intravenous drug abusers. CONCLUSIONS: Greater awareness of all aspects of hepatitis C infection and its risks to the practice of surgery is required. Further debate is necessary on the role of routine testing of surgeons and patients.

Difficult Airway Society guidelines for management of the unanticipated difficult intubation.

UNLABELLED: Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS. DISCLAIMER: It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.