Determining competence in performing obstetric combined spinal-epidural procedures in junior anesthesiology residents: results from a cumulative sum analysis.

BACKGROUND: The epidural anesthesia technique is a challenging skill to master. The Accreditation Council for Graduate Medical Education (ACGME) stipulates that anesthesiology residents must complete 40 epidural procedures by the end of junior residency. The rationale is unknown. The aim of this prospective study was to determine the minimum case experience required to demonstrate competence in performing obstetric combined spinal-epidural procedures among junior residents, using an objective statistical tool, the cumulative sum (CUSUM) analysis. METHODS: Twenty-four residents, with no prior experience performing epidurals, sequentially recorded all obstetric combined spinal-epidural procedures as a 'success' or 'failure', based on study criteria. Individual CUSUM graphs were plotted, with acceptable and unacceptable failure rates set at 20% and 35%, respectively. The number of procedural attempts necessary to demonstrate competence was determined. RESULTS: Twenty-four residents (mean (SD) age 29 (2) years) participated in the study. Median (IQR) number of procedures was 78 (66-85), with a median (IQR) success rate of 86% (82-89%). Nineteen of 24 residents required a median (IQR) of 40 (33-50) attempts to demonstrate competence. Five did not achieve procedural competence in the training period. The CUSUM graphs highlighted performance trends that required intervention. CONCLUSION: Competence was achieved by 19/24 residents after the ACGME-required case experience of 40 combined spinal-epidural procedures, based on a predefined acceptable failure rate of 20%. In our experience, CUSUM analysis is useful in monitoring technical performance over time and should be included as an adjunct assessment method for determining procedural competence.

Considerations and strategies in the organisation of obstetric anaesthesia care during the 2019 COVID-19 outbreak in Singapore.

The provision of safe obstetric anaesthesia services is essential during the COVID-19 global outbreak. The identification of the 'high-infection risk' parturient can be challenging especially with the rapidly changing risk criteria for COVID-19 'cases'. A multidisciplinary taskforce is required to review the infection control protocols and workflows for managing the parturient for labour analgesia and for caesarean section in order to minimize infection risk to healthcare staff and other parturients. A constant review of such processes is needed to enhance efficiency and to optimise use of finite resources. Good communication between health officials, institutional leadership and ground staff is essential for the dissemination of information.

Exploring the challenges of task-centred training in obstetric anaesthesia in the operating theatre environment.

BACKGROUND: Task-centred learning forms the basis of procedural training in obstetric anaesthesia. We observed that our residents were not building their competence from experiential practice in the operating theatre. We used a broad-based framework to explore the challenges encountered by the residents and clinical supervisors in the learning and teaching of obstetric anaesthesia. METHODS: The study was conducted at the KK Women's and Children's Hospital, Singapore, from 1 December 2016 to 30 June 2017. A semi-structured interview format was used in the focus group and individual interviews. Information collection continued until data saturation was reached. The interviews were analysed and the challenges were identified. Fourteen residents and five clinical supervisors participated in the focus group and individual interviews respectively. FINDINGS: The operating theatre constituted a stressful learning and teaching environment for the participants. Five categories of challenges were identified: (1) clinical conditions, (2) concerns about maternal risk and outcomes, (3) reluctance of the residents to vocalise their learning needs, (4) poor feedback, and (5) lack of opportunities for inter-professional practice. These collective challenges reduced the quality of task-centred learning and the effectiveness of supervisor teaching. We described some strategies to overcome these challenges (dedicated trainee lists, obstetric anaesthesia reflective diary, active mentoring system and in-situ simulation). CONCLUSIONS: Our study described the challenges of obstetric anaesthesia training in the operating theatre environment in an Asian healthcare setting. Research is needed on the influence of supervisors' concern about maternal risks and their teaching behaviours.

Blood loss in spinal tumour surgery and surgery for metastatic spinal disease: a meta-analysis.

There is currently no consensus about the mean volume of blood lost during spinal tumour surgery and surgery for metastatic spinal disease. We conducted a systematic review of papers published in the English language between 31 January 1992 and 31 January 2012. Only papers that clearly presented blood loss data in spinal surgery for metastatic disease were included. The random effects model was used to obtain the pooled estimate of mean blood loss. We selected 18 papers, including six case series, ten retrospective reviews and two prospective studies. Altogether, there were 760 patients who had undergone spinal tumour surgery and surgery for metastatic spinal disease. The pooled estimate of peri-operative blood loss was 2180 ml (95% confidence interval 1805 to 2554) with catastrophic blood loss as high as 5000 ml, which is rare. Aside from two studies that reported large amounts of mean blood loss (> 5500 ml), the resulting funnel plot suggested an absence of publication bias. This was confirmed by Egger's test, which did not show any small-study effects (p = 0.119). However, there was strong evidence of heterogeneity between studies (I(2) = 90%; p < 0.001). Spinal surgery for metastatic disease is associated with significant blood loss and the possibility of catastrophic blood loss. There is a need to establish standardised methods of calculating and reporting this blood loss. Analysis should include assessment by area of the spine, primary pathology and nature of surgery so that the amount of blood loss can be predicted. Consideration should be given to autotransfusion in these patients.

The impact of manual in-line stabilisation on ventilation and visualisation of the glottis with the LMA CTrach: a randomised crossover trial.

The LMA CTrach (CTrach) enables ventilation, glottis visualisation and tracheal intubation via a laryngeal mask conduit. The CTrach has been successfully used in patients with cervical spine pathology, but it is unclear if cervical spine immobilisation affects its ease of use. In this randomised crossover trial, the CTrach was used once with and once without manual in-line stabilisation of the cervical spine in every patient. With manual in-line stabilisation, the median [IQR] time to achieve ventilation was 22 [16-32] s, compared with 19 [13-30] s without stabilisation (p = 0.065). With manual in-line stabilisation, the time to achieving a glottic views was 42 [30-63] s compared with 39 [25-53] s without stabilisation (p = 0.019). There was no difference in the success rates of achieving ventilation and glottic views. These results suggest that manual in-line stabilisation does not affect use of the CTrach.

Tracheal intubation with videolaryngoscopes in patients with cervical spine immobilization: a randomized trial of the Airway Scope and the GlideScope.

BACKGROUND: The GlideScope (Verathon Inc., Bothell, WA, USA) and Airway Scope (Hoya Corp., Tokyo, Japan) have both been used for difficult airway management, including in patients with cervical spine pathology. The Airway Scope's disposable blade has a tube channel to guide tracheal tube insertion through the glottis. Our hypothesis is that this tube guidance system improves the ease of tracheal intubation compared with the GlideScope, which does not have a tube guiding system. We tested this hypothesis in a randomized comparison of the two videolaryngoscopes in patients whose cervical spines were immobilized. METHODS: Seventy consenting patients were randomized to have tracheal intubation with the GlideScope (n=35) or the Airway Scope (n=35). In all patients, we applied manual in-line stabilization of the cervical spine throughout airway management. All the airway procedures were carried out by two anaesthetists experienced in the use of both videolaryngoscopes. RESULTS: The tracheal intubation time was 34.2 (sd 25.1) s with the Airway Scope compared with 71.9 (47.9) s with the GlideScope (P<0.001). Tracheal intubation was successful with the Airway Scope in 35 (100%) patients compared with 31 (88.6%) patients with the GlideScope (P=0.114). Tracheal intubation was successful within 60 s in 33 (94.3%) patients with the Airway Scope and 22 (62.9%) patients with the GlideScope (P=0.003). CONCLUSIONS: These results suggest that the Airway Scope's tube guide system enables more rapid tracheal intubation compared with the GlideScope in patients with cervical spine immobilization.

Ease of intubation with the GlideScope or Airway Scope by novice operators in simulated easy and difficult airways--a manikin study.

The GlideScope and Airway Scope are video laryngoscopes that have been found to be useful in difficult airway situations. With the GlideScope, there are frequently problems associated with insertion of the tracheal tube despite the ability to view the glottis. The Airway Scope's imaging system and disposable PBlade aid alignment of the PBlade with the glottis and guide insertion of the tracheal tube. We performed a randomised crossover study of 20 medical students using both videolaryngoscopes in a manikin, with simulated normal and difficult airway scenarios. We found that the students required less time for tracheal intubation with the Airway Scope and reported greater ease of intubation with the Airway Scope in both scenarios. A greater number of students chose the Airway Scope as their device of choice. Our results suggest that the Airway Scope's features may improve the ease of tracheal intubation compared with the GlideScope.

Cricoid pressure prevents placement of the laryngeal tube and laryngeal tube-suction II.

BACKGROUND: The laryngeal tube has a potential role in patients with a difficult airway, but cricoid pressure is required if the patient is at risk of aspiration. The effect of cricoid pressure on insertion of these devices is unknown. METHODS: In a randomized cross-over study, the laryngeal tube (25 patients) or the laryngeal tube-suction II (15 patients) was inserted with cricoid pressure applied on one occasion and with sham pressure on the other occasion. Adequacy of ventilation, time to achieve adequate ventilation, and the leak pressure were assessed. RESULTS: Ventilation was adequate in all patients when sham pressure was applied. Cricoid pressure significantly reduced the rate of adequate ventilation to 6 of 25 patients for the laryngeal tube [P < 0.001; 95% confidence interval (CI) for difference: 59-93%] and to 5 of 15 patients for the laryngeal tube-suction II (P < 0.05; 95% CI for difference: 43-91%). The median time taken to achieve adequate ventilation for the laryngeal tube was 10 s [inter-quartile range (IQR): 8-15] (range 5-26) for sham pressure and 25 s (15-32) (15-33) for cricoid pressure; the median leak pressure was 30 (IQR: 30-30) (range 20-30) cm H2O for sham pressure and 15.5 (14.3-20.5) (12-22) cm H2O for cricoid pressure. CONCLUSIONS: Continuous cricoid pressure prevents correct placement of the laryngeal tube and the laryngeal tube-suction II such that placement and ventilation via these devices are ineffective. The effect of cricoid pressure on ventilation via these devices, after correct placement, remains unknown.

An evaluation of poor LMA CTrach views with a fibreoptic laryngoscope and the effectiveness of corrective measures.

BACKGROUND: The LMA CTrach++ system has integrated fibreoptics to enable viewing of the glottis to aid tracheal intubation via a laryngeal mask conduit. Earlier evaluations of this system had shown high success rates of insertion, ventilation and tracheal intubation, but frequent difficulty or failure to view the glottis. METHOD: We evaluated CTrach views in 100 patients. In 69 patients with partial or no views of the glottis, we evaluated the causes with the aid of an Olympus LF-DP fibreoptic laryngoscope passed through the CTrach. In those with poor views, we tested the effectiveness of simple corrective measures to improve the views and optimize CTrach placement. These included pushing the CTrach deeper in, partial withdrawal by 6 cm and reinsertion to correct epiglottic downfolding, withdrawal by 1 cm and applying forward lift to correct obstruction by the arytenoids, and complete removal to clean the fibreoptic ports followed by reinsertion when secretions were the problem. RESULTS: Downfolding of the epiglottis caused poor views in 57 patients, which was correctable in 51. Obstruction of the view by the arytenoids occurred in seven patients and by secretions in five, all of which were correctable. With the Ctrach, we were able to ventilate the lungs in all patients, view the glottis in 94 and intubate the trachea in 97 patients. CONCLUSION: Despite the ability to ventilate the lungs in all patients with the CTrach, poor initial views were very frequent, indicating suboptimal placement, although most poor views can be improved, leading to a high intubation success rate.

The LMA CTrach, a new laryngeal mask airway for endotracheal intubation under vision: evaluation in 100 patients.

BACKGROUND: The LMA CTrach is a new laryngeal mask system consisting of an LMA CTrach Airway with integrated fibreoptic channels, and a detachable LMA CTrach Viewer. This system enables viewing of the larynx and aids endotracheal intubation through a laryngeal mask airway. Method. We used and evaluated this system in 100 adult patients undergoing general anaesthesia for elective surgery. Our primary outcomes were the success rates of LMA CTrach Airway insertion and endotracheal intubation with this system. RESULTS: We were able to insert the LMA CTrach Airway in and to ventilate all 100 patients. We were successful in endotracheal intubation, either under vision or blind, in 96 patients. We were able to view the larynx in 84 patients, but the quality of the best view obtained was very variable. The median (inter quartile range) time for the complete intubation process was 166 (114-233) s. The system allowed nearly continuous ventilation and oxygenation during the process. CONCLUSIONS: The LMA CTrach system has potential advantages over the LMA Fastrach system, including the ability to align the LMA outlet with the larynx and a high first intubation attempt success rate. However, it was difficult to view the larynx with the LMA CTrach compared with direct laryngoscopy, and expectations must be moderated.

Neuraxial block for labour analgesia--is the combined spinal epidural (CSE) modality a good alternative to conventional epidural analgesia?

AIM: Apart from conventional epidural analgesia (EA), the combined spinal-epidural (CSE) modality is fast becoming a popular technique for treating labour pain. In this study, we investigated the differences in the patient profile and outcome between CSE and EA for labour pain in KK Women's and Children's Hospital. METHODOLOGY: Data pertaining to 1,532 healthy parturients who had received either CSE or EA for labour pain during a six-month period was systematically collected by using a specially designed form. Multiple logistic regression analysis was used to determine the independent predictors of patient satisfaction and the relation of parturient factors on the choice of block. The side effects and the outcome of labour were also compared. RESULTS: CSE accounted for 80% of all neuraxial blocks performed for labour analgesia (vs 20% for EA). Anaesthesiologists were more inclined to using CSE than EA for multiparous parturients (OR 2.03, p<0.01) in a more painful (OR=1.61, p=0.03) and advanced stage of labour (OR=1.12, p=0.03). The need for supplemental analgesics was greater for EA (p<0.01). Patient satisfaction was higher for CSE (OR=1.77, p<0.026). CSE had a higher risk of pruritus (29% vs 14%, p<0.01) but lower risk of post block neural deficits (0% vs 2%, p<0.01) than EA. No difference in the mode of delivery was detected between the two groups. CONCLUSION: CSE is a safe and good alternative to EA as a technique of neuraxial block for labour analgesia.

Pulse dye densitometry: a novel bedside monitor of circulating blood volume.

INTRODUCTION: Monitoring of circulating blood volume is important in the management of critically ill patients. Current methods of circulating blood volume measurements such as indicator dilution using radioisotopes or Evans blue dye are unsuitable for clinical application as these tests do not allow for frequent repeated measurements to be done. A direct bedside measurement of circulating blood volume using the principle of pulse dye densitometry was recently introduced. This is essentially an indicator dilution technique using indocyanine green combined with the principle of pulse spectrophotometry. METHODS: This paper aims to review this method of circulating blood volume measurement and provide a summary of the published clinical trials that compared its accuracy with the other conventional methods of circulating blood volume measurement, based on a Medline search, spanning the period 1966 to August 2000. RESULTS: Published studies show that pulse dye densitometry gives comparable results when compared to other conventional methods of blood volume measurement. Its ability to measure circulating blood volume accurately and repeatedly, as frequently as every 20 min makes it suitable for clinical application. CONCLUSION: Pulse dye densitometry provides for a rapid, semi-noninvasive and convenient bedside assessment of circulating blood volume that is applicable clinically. Further studies are needed to ascertain the impact of the use of pulse dye densitometry on the mortality and morbidity of the critically ill.

Prenatal exposure of female rhesus monkeys to testosterone propionate increases serum luteinizing hormone levels in adulthood.

OBJECTIVE: To determine whether prenatal androgenization of the developing primate hypothalamohypophyseal unit induces irreversible changes in LH secretion. DESIGN: Prospective nonrandomized study. SETTING: An academic research environment. ANIMALS: Forty-one adult ovulatory female rhesus monkeys. INTERVENTION(S): Seventeen female rhesus monkeys exposed prenatally to testosterone propionate (female pseudohermaphrodites) and 24 normal females underwent blood sampling over two ovulatory menstrual cycles. MAIN OUTCOME MEASURE(S): Serum FSH, LH, E2, and T were determined by RIA; P was determined by enzyme immunoassay. Serum bioactive LH was measured by mouse Leydig cell bioassay. RESULT(S): Tonic immunoactive LH hypersecretion and normal FSH release occurred in female pseudohermaphrodites compared with normal females. Periovulatory immunoactive LH and FSH secretion was similar in both female types, whereas a relative increase in the amount of circulating bioactive LH to immunoactive LH was found at midcycle in female pseudohermaphrodites versus normal females. The length of the follicular phase was unaffected by prenatal androgen exposure, but the slopes of serum T and E2 concentrations versus follicular phase cycle day were significantly lower in female pseudohermaphrodites than normal females. Luteal phase length and P secretion were comparable in both types of females. CONCLUSION(S): Androgen exposure during primate neural differentiation may alter permanently the pattern of LH secretion in the presence of cyclic gonadotropin release.

The effects of diethylstilbestrol (DES) before birth on the development of masculine behavior in juvenile female rhesus monkeys.

Eight pregnant rhesus monkeys were injected with 100 microg diethylstilbestrol dipropionate (DESDP) from the 40th day of gestation until term, a long-term treatment. Male (n = 3) and female (n = 5) offspring were obtained. Five other pregnant females were injected with DESDP beginning on the 115th day of gestation and continuing until either the 140th day or term--a relatively short-term treatment. Five female infants were obtained from these short-term treatments. Monkeys from the treated pregnancies were assigned randomly to mother-infant social groups containing untreated male and female infants the same age. They were observed in their peer groups each weekday from 3 to 12 months of age, and the display of mounting and play behavior was recorded for each subject. Results showed that DESDP significantly increased the frequency of display of these juvenile behaviors only in long-term-treated females. However, one of the aspects of mounting that is characteristic of males (the ratio of complete to abortive mounts) was unaffected even by the long-term treatment. Thus, DESDP-treated females displayed a limited behavioral masculinization. Whether this limitation was due to dosage and/or timing or to a selective action of DESDP was not determined. DESDP-treated males were not altered in any measurable way compared to untreated males.

Idazoxan decreases estrogen-induced lordosis in female but not "hormone-independent" lordosis in male guinea pigs of an inbred strain.

This experiment examined whether the imidazoline idazoxan (which binds to alpha-noradrenergic receptors and to imidazoline-preferring sites) interferes with hormone-dependent or hormone-independent lordosis responses. Ovariectomized (ovx) Strain 2 female guinea pigs which were sexually receptive after receiving estradiol benzoate (EB; 3 micrograms/d for 3 days) were injected with either idazoxan (10 mg/kg) or with vehicle at 24 hr after the last EB injection. Idazoxan significantly decreased EB-facilitated lordosis responses in these females. Castrated Strain 2 males, which show lordosis behavior without gonadal hormone administration, were injected with the same dosage of idazoxan (10 mg/kg) or with vehicle. Idazoxan did not inhibit lordosis behavior in these males.

In utero and lactational exposure of male rats to 2,3,7,8-tetrachlorodibenzo-p-dioxin. 2. Effects on sexual behavior and the regulation of luteinizing hormone secretion in adulthood.

When administered to postpubescent male rats, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) decreases plasma androgen concentrations. If such an androgenic deficiency were produced prenatally and/or early postnatally it could impair sexual differentiation of the central nervous system (CNS) and thereby alter male reproductive function. To examine this possibility, sexually dimorphic functions were assessed in male rats born to dams given TCDD (0.064, 0.16, 0.40, and 1.0 micrograms/kg, po) or vehicle on Day 15 of gestation. Masculine sexual behavior was assessed at approximately 60, 75, and 115 days of age. When TCDD-exposed males were caged with receptive control females their mount, intromission, and ejaculation latencies were far longer than normal; these effects were dose-related and were statistically significant at maternal doses as low as 0.16, 0.064, and 0.16 micrograms TCDD/kg, respectively. The numbers of mounts and intromissions to ejaculation were slightly increased by TCDD, while copulatory rates [(mounts+intromissions)/min] were significantly decreased at the three highest maternal doses. Except for a modest increase at the higher doses, TCDD had little effect on the postejaculatory interval. Following assessment of their masculine sexual behavior, the males were castrated and 6 weeks later tested for feminine sexual behavior (lordosis). After being primed with estradiol benzoate and treated with progesterone, males displayed dose-related increases in lordosis quotient and lordosis intensity in response to being mounted by another male. These effects were statistically significant at maternal doses as low as 0.16 and 0.40 micrograms TCDD/kg, respectively. To determine if perinatal TCDD exposure alters the sexually dimorphic regulation of luteinizing hormone (LH) secretion, the LH secretory responsiveness of the hypothalamic/pituitary axis to ovarian steroids was assessed. In unexposed, gonadectomized female rats primed with estradiol benzoate, progesterone injection produced a surge in plasma LH concentrations, whereas in similarly treated control males, plasma LH concentrations were unaffected by progesterone. In castrated, estradiol benzoate-primed male rats that were perinatally exposed to TCDD, progesterone treatment produced dose-related increases in plasma LH concentrations that were statistically significant at the two highest maternal doses. We conclude that in utero and lactational exposure to small amounts of TCDD demasculinizes and feminizes male rats. These effects cannot be accounted for by TCDD-induced hypophagia, modest reductions in adult plasma androgen concentrations, possible nonspecific changes in motor activity, or possible reductions in penile sensitivity to sexual stimulation. The altered sexual behaviors and LH secretion were observed when nearly all TCDD had been excreted (as evidenced by uninduced hepatic ethoxyresorufin-O-deethylase activity).(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of prenatal antiandrogen treatment on masculinization and defeminization of guinea pigs.

Gonadectomized (gdx) guinea pigs which had received the antiandrogen flutamide prenatally were tested for female-typical and male-typical sexual behavior in adulthood. In tests for lordosis behavior, gdx males and females were injected with estradiol benzoate and progesterone. Prenatally flutamide-treated females showed a longer mean lordosis response than control females. This was true whether they were given either a high or a low dose of EB. No male ever showed a lordosis response. In tests for male-typical sexual behavior, gdx adult males were treated with testosterone propionate and tested with stimulus females. The prenatally flutamide-treated males showed significantly decreased levels of ejaculation, a lower intromission rate and a decreased percentage of mounts which included pelvic thrusts, when compared to control males. Mount rate and rate of pericopulatory behavior did not differ between the flutamide and control males. The fact that prenatal administration of flutamide increased female-typical behavior in adult females suggests that the female guinea pig is normally partially defeminized by androgens in utero. The male guinea pig appears to be resilient to attempts to block defeminization with prenatal antiandrogens. However, some aspects of masculinization can be blocked.