Practical simulation training for maternity care--where we are and where next.

Improving maternal and perinatal care is a global priority. Practical simulation training for maternity care might prevent many of these deaths. There have been numerous evaluation studies published on the effectiveness of simulation training for obstetric emergencies, with increasing evidence that it is associated with improvement in clinical outcomes. Evidence has begun to move from subjective assessment of participants' experiences towards objective assessment of clinical outcomes. However, the results are not entirely consistent and, at present, all of the evidence associating training with improvements in clinical outcomes relates to neonatal outcomes. This review summarises recent progress in the evaluation of the effectiveness of simulation training for maternity care in both high- and low-resource settings, and presents a vision for ensuring that practical simulation training for maternity care can become an effective tool to reduce global maternal and perinatal morbidity and mortality.

A randomised trial comparing the levonorgestrel intrauterine system and thermal balloon ablation for heavy menstrual bleeding.

OBJECTIVE: To compare the levonorgestrel intrauterine system (LNG-IUS) (Mirena); Schering Co., Turku, Finland) and thermal balloon ablation (Thermachoice; Gynecare Inc., Menlo Park, CA, USA) for the treatment of heavy menstrual bleeding. DESIGN: An open, pragmatic, prospective randomised trial. SETTING: A menstrual disorders clinic at National Women's Hospital, Auckland, New Zealand. POPULATION: Seventy-nine women with heavy menstrual bleeding randomised to the LNG-IUS (40 women) or the thermal balloon ablation (39 women). METHODS: Women were randomised to treatment with the LNG-IUS or thermal balloon ablation and followed up by a postal and telephone questionnaire. MAIN OUTCOME MEASURES: Menstrual loss measured by a pictorial bleeding assessment chart (PBAC) at 3, 6, 12 and 24 months. Patient satisfaction, quality of life and menstrual symptoms were assessed by questionnaire administered at 3, 6, 12 and 24 months. Treatment side effects and treatment failures were also recorded. RESULTS: Both the treatments resulted in a significant reduction in PBAC scores. At 12 and 24 months, median PBAC scores were significantly lower in women treated with the LNG-IUS compared with women treated by thermal balloon ablation (11.5 versus 60.0 at 12 months [P= 0.002]; 12.0 versus 56.5 [P= 0.002] at 24 months). At 24 months, nine (35%) women still using the LNG-IUS had amenorrhoea compared with one (5%) woman successfully treated by thermal balloon ablation (P = 0.025). There were no significant differences in patient satisfaction between two treatments during follow up. Treatment failed in 11 (28%) women using the LNG-IUS and in 10 (26%) women treated with thermal balloon ablation. Overall, women in both groups showed an increased quality of life as a result of the treatment, with Short Form-36 scores increasing from 63.7 at randomisation to 76.1 at 24 months. CONCLUSIONS: At 12 and 24 months of follow up, women with heavy menstrual bleeding treated with the LNG-IUS have significantly lower PBAC scores than women treated with thermal balloon ablation. Both the treatments resulted in a significant increase in overall quality of life, but there were no significant differences between either treatment in quality of life, patient satisfaction or the number of women requesting an alternative treatment during 24 months of follow up.

Surgical treatment for tubal disease in women due to undergo in vitro fertilisation.

BACKGROUND: Tubal disease, and particularly hydrosalpinx, has a detrimental effect on the outcome of in-vitro fertilisation (IVF). It has been less clear whether surgical intervention for tubal disease prior to IVF is effective in improving the likelihood of successful outcome. Most data are retrospective or poorly controlled. To date no single prospective randomised trial has shown a significant benefit from such surgical treatment prior to IVF. OBJECTIVES: To assess the value of surgical treatment for tubal disease prior to IVF. SEARCH STRATEGY: We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (10 March 2004), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2004), MEDLINE (January 1966 to February 2004), EMBASE (January 1985 to February 2004), reference lists of articles and contacted researchers in the field. SELECTION CRITERIA: All trials comparing a surgical treatment for tubal disease with a control group generated by randomisation were considered for inclusion in the review. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. The studied outcomes were live birth (and ongoing pregnancy), pregnancy, ectopic pregnancy, miscarriage, multiple pregnancy and complications. MAIN RESULTS: Three randomised controlled trials involving 295 (or couples) were included in this review. The odds of ongoing pregnancy and live birth (Peto odds ratio (OR) 2.13, 95% confidence interval (CI) 1.24 to 3.65) were increased with laparoscopic salpingectomy for hydrosalpinges prior to IVF. The odds of pregnancy were also increased (Peto odds ratio (OR )1.75, 95%CI 1.07 to 2.86). There was no significant difference in the odds of ectopic pregnancy (Peto OR 0.42, 95%CI 0.08 to 2.14), miscarriage (Peto OR 0.49, 95%CI 0.16 to 1.52) or treatment complications (Peto OR 5.80, 95%CI 0.35 to 96.79). No data were available concerning the odds of multiple pregnancy. REVIEWERS' CONCLUSIONS: Laparoscopic salpingectomy should be considered for all women with hydrosalpinges prior to IVF treatment. Currently unilateral salpingectomy for a unilateral hydrosalpinx (bilateral salpingectomy for bilateral hydrosalpinges) should be recommended, although this requires further evaluation. Further randomised trials are required to assess other surgical treatments for hydrosalpinx, such as salpingostomy, tubal occlusion or needle drainage of a hydrosalpinx at oocyte retrieval. The role of surgery for tubal disease in the absence of a hydrosalpinx is unclear and merits further evaluation.

Pre-operative endometrial thinning agents before endometrial destruction for heavy menstrual bleeding.

BACKGROUND: Menorrhagia is one of the most common reasons for pre-menopausal women to be referred to a gynaecologist. Although medical therapy is generally the first approach, many women will eventually require or request a hysterectomy. Hysterectomy is associated with a significant in-patient hospital stay and a period of convalescence that makes it an unattractive and unnecessarily invasive option for many women. Hysteroscopic endometrial ablation or resection, and more recently "second generation" devices such as balloon or microwave ablation offer a day-case surgical alternative to hysterectomy for these women. They are also cheaper procedures than hysterectomy. Complete endometrial removal or destruction is one of the most important determinants of treatment success. Therefore surgery will be most effective if undertaken when endometrial thickness is less than four mm, in the immediate post-menstrual phase, however there are often difficulties in reliably arranging surgery for this time. The other option is the use of hormonal agents which induce endometrial thinning or atrophy prior to surgery. The most commonly evaluated agents have been goserelin (a GnRH analogue) and danazol. Progestogens and other GnRH analogues have also been studied although less data are available. It has been suggested that the use of these agents, particularly GnRH analogues, will reduce operating time, improve the intra-uterine operating environment, and reduce distension medium absorption (this is the fluid used to distend the uterine cavity during surgery). They may also result in a greater improvement in long term outcomes such as menstrual loss and dysmenorrhoea. OBJECTIVES: To investigate the effectiveness of gonadotrophin-releasing hormone (GnRH) analogues, danazol, and progestogens, when used for endometrial thinning prior to endometrial destruction for menorrhagia, in improving the intra-uterine operating environment and treatment outcome after surgery. SEARCH STRATEGY: The Menstrual Disorders and Subfertility Group search strategy (see Review Group details) was used to identify randomised trials that had compared the use of these drugs with either each other, or placebo, or no pre-operative treatment. An updated search was performed in 2001-2002 to identify new trials. SELECTION CRITERIA: Trials were included if they compared the effects of these agents with each other, or with placebo or no treatment on relevant intra-operative and post-operative treatment outcomes. Only randomised studies were included in this review. DATA COLLECTION AND ANALYSIS: Twelve studies met the inclusion criteria for this review. Five studies compared goserelin (a GnRH analogue) with no treatment or placebo and one study compared decapeptyl (a GnRH analogue) with no treatment. Three studies compared goserelin with danazol. Two studies compared progestogens, danazol and triptorelin or nasal spray nafarelin (both GnRH analogues) with no treatment. Only one study comparing triptorelin with no treatment assessed outcomes after balloon ablation and no studies assessing endometrial thinning agents prior to other second generation ablation techniques were identified. One study assessed the effects of progestogens compared to no treatment. Data were extracted independently by two reviewers. A third reviewer checked data extraction for accuracy and wrote to authors where relevant data was missing or unclear. Intra-operative parameters included endometrial thickness, duration of surgery, ease of surgery, distension medium absorption and complication rate. Post-operative outcomes included the proportion of women with amenorrhoea, post-operative menstrual loss and dysmenorrhoea, and the need for further surgery. Data on side-effects were also recorded. MAIN RESULTS: When compared with no treatment, GnRH analogues are associated with a shorter duration of surgery, greater ease of surgery and a higher rate of post-operative amenorrhoea at 12 months with hysteroscopic resection or ablation. Post-operative dysmenorrhoea also appears to be reduced. The use of GnRH analogues has no effect on intra-operative complication rates and patient satisfaction with this surgery is high irrespective of the use of any pre-operative endometrial thinning agent. GnRH analogues produce more consistent endometrial atrophy than danazol. For other intra-operative and post-operative outcomes, any differences are minimal and there were no benefits of GnRHa pre-treatment in the one small study where women had balloon (second generation ablation). Both GnRH analogues and danazol produce side-effects in a significant proportion of women, though few studies have reported these in detail. Few randomised data are available to assess the effectiveness of progestogens as endometrial thinning agents. The effect of any thinning agent on longer-term results is less certain but where reported the effect of endometrial thinning agents on benefits such as post-operative amenorrhoea appears to reduce with time. REVIEWER'S CONCLUSIONS: Endometrial thinning prior to hysteroscopic surgery in the early proliferative phase of the menstrual cycle for menorrhagia improves both the operating conditions for the surgeon and short term post-operative outcome. Gonadotrophin-releasing hormone analogues produce slightly more consistent endometrial thinning than danazol, though both agents produce satisfactory results. The effect of these agents on longer term post-operative outcomes such as amenorrhoea and the need for further surgical intervention reduces with time.

Laparoscopic salpingectomy for women with hydrosalpinges enhances the success of IVF: a Cochrane review.

BACKGROUND: The aim of this study was to determine whether surgical intervention is effective for women with tubal disease who are due to undergo treatment with IVF. METHODS: A systematic review employing the principles of the Cochrane Menstrual Disorders and Subfertility Group was undertaken. Three randomized controlled trials were included, the population of women in all three studies having hydrosalpinges. RESULTS: The odds of pregnancy [odds ratio (OR) = 1.75, 95% confidence interval (CI) 1.07-2.86] and of ongoing pregnancy and live birth (OR = 2.13, 95% CI 1.24-3.65) were increased with laparoscopic salpingectomy for hydrosalpinges prior to IVF. There were no significant differences in the odds of embryo implantation (OR = 1.34, 95% CI 0.87-2.05), ectopic pregnancy (OR = 0.42, 95% CI 0.08-2.14), miscarriage (OR = 0.49, 95% CI 0.16-1.52) or treatment complications (OR = 5.80, 95% CI 0.35-96.79). No data were available concerning the odds of multiple pregnancy or the proportion of IVF cycles resulting in embryo transfer. CONCLUSION: Laparoscopic salpingectomy should be considered for all women with hydrosalpinges due to undergo IVF; further research is required to assess other pre-IVF surgical interventions (such as needle aspiration of hydrosalpinx fluid, laparoscopic proximal tubal occlusion and laparoscopic salpingostomy) for women with hydrosalpinges.

Surgical treatment for tubal disease in women due to undergo in vitro fertilisation.

BACKGROUND: Tubal disease, and particularly hydrosalpinx, has a detrimental effect on the outcome of in-vitro fertilisation (IVF). It has been less clear whether surgical intervention for tubal disease prior to IVF is effective in improving the likelihood of successful outcome. Most data are retrospective or poorly controlled. To date no single prospective randomised trial has shown a significant benefit from such surgical treatment prior to IVF. OBJECTIVES: To assess the value of surgical treatment for tubal disease prior to IVF. SEARCH STRATEGY: The search strategy of the Menstrual Disorders and Subfertility Group was used for the identification of relevant randomised controlled trials. SELECTION CRITERIA: All trials where a surgical treatment for tubal disease was compared with a control group generated by randomisation were considered for inclusion in the review. DATA COLLECTION AND ANALYSIS: Three randomised controlled trials were identified and included in this review, after an attempt to obtain further information from the authors of all three trials. All trials were assessed for quality criteria. The studied outcomes were live birth (and ongoing pregnancy), pregnancy, ectopic pregnancy, miscarriage, multiple pregnancy, complications, implantation rate and the proportion of IVF cycles resulting in embryo transfer. MAIN RESULTS: The odds of pregnancy (OR 1.75, 95%CI 1.07, 2.86) and of ongoing pregnancy and live birth (OR 2.13, 95%CI 1.24, 3.65) were increased with laparoscopic salpingectomy for hydrosalpinges prior to IVF. There was no significant difference in the odds of ectopic pregnancy (OR 0.42, 95%CI 0.08, 2.14), miscarriage (OR 0.49, 95%CI 0.16, 1.52), treatment complications (OR 5.80, 95%CI 0.35, 96.79) or implantation rate (OR 1.34, 95%CI 0.87, 2.05). No data were available concerning the odds of multiple pregnancy or the proportion of IVF cycles resulting in embryo transfer. REVIEWER'S CONCLUSIONS: Laparoscopic salpingectomy should be considered for all women with hydrosalpinges prior to IVF treatment. Currently unilateral salpingectomy for a unilateral hydrosalpinx (bilateral salpingectomy for bilateral hydrosalpinges) should be recommended, although this requires further evaluation. Further randomised trials are required to assess other surgical treatments for hydrosalpinx, such as salpingostomy, tubal occlusion or needle drainage of a hydrosalpinx at oocyte retrieval. The role of surgery for tubal disease in the absence of a hydrosalpinx is unclear and merits further evaluation.

A randomised trial comparing single dose systemic methotrexate and laparoscopic surgery for the treatment of unruptured tubal pregnancy.

OBJECTIVE: To compare single dose systemic methotrexate (50 mg/m2) with laparoscopic surgery for the treatment of unruptured tubal pregnancy. DESIGN: An open, pragmatic, prospective randomised trial. SETTING: Departments of obstetrics and gynaecology at three hospitals in Auckland, New Zealand. PARTICIPANTS: Clinically stable women with an unruptured tubal pregnancy diagnosed by transvaginal ultrasound and quantitative serum beta-hCG measurement. Inclusion criteria included a serum beta-hCG concentration < 5,000 IU/L, and a tubal pregnancy of < 3.5 cm diameter. MAIN OUTCOME MEASURES: Treatment success, physical and psychological functioning, side effects, and subsequent ipsilateral tubal patency. RESULTS: Two hundred and eighteen women with ectopic pregnancies were seen at the three hospitals. 79 women (36% eligibility rate) were eligible for trial entry and 62 women (78% recruitment rate) were recruited. Twenty-six of the 28 women (93%) randomised to laparoscopic surgery required no further treatment, compared with 22 of the 34 women (65%) randomised to methotrexate (95% CI of difference in success rate 10 - 47%; P < 0.01). Two women (7%) in the laparoscopic surgery group had persistent trophoblast. Nine women (26%) in the methotrexate group required more than one dose of methotrexate and five women (15%) underwent laparoscopy during follow up. In the laparoscopy group three women (11%) had negative laparoscopies and two women (7%) had were found to have a ruptured fallopian tube at the time of surgery. Women treated with methotrexate had significantly better objective physical functioning scores but there were no differences in any other psychological outcomes. Women treated with methotrexate experienced greater and more prolonged vaginal bleeding. The likelihood of methotrexate treatment failure was greater at higher serum beta-hCG concentrations. Ipsilateral tubal patency rates were similar in each group. CONCLUSION: This trial shows that in the treatment of tubal pregnancy single dose systemic methotrexate is a less effective treatment than laparoscopic salpingotomy. It is well tolerated, but should only be offered as an alternative to surgery to women who have mild symptoms and present at low serum beta-hCG concentrations. In our population this likely to be no more than a quarter of women presenting with a tubal pregnancy.

An economic evaluation of single dose systemic methotrexate and laparoscopic surgery for the treatment of unruptured ectopic pregnancy.

OBJECTIVE: To compare the direct and indirect costs of single dose systemic methotrexate with laparoscopic surgery for the treatment of unruptured ectopic pregnancy. DESIGN: A cost minimisation study undertaken alongside a randomised trial. SETTING: Departments of Obstetrics and Gynaecology in three hospitals in Auckland, New Zealand. PARTICIPANTS: Sixty-two women with an ectopic pregnancy randomised to treatment with either a single dose of methotrexate (50 mg/m2) or laparoscopic surgery. MAIN OUTCOME MEASURES: Direct and indirect costs based on the results of the randomised trial. RESULTS: Direct costs per case were significantly lower in the methotrexate group (mean $NZ 1,470) than in the laparoscopy group (mean $NZ 3,083) with a mean difference of $NZ 1,613 (95% CI $NZ 1,166 - $NZ 2,061). These significant differences existed under a wide range of alternative assumptions about unit costs. The difference in direct costs in favour of methotrexate was greatest for women presenting with low pretreatment serum beta-hCG concentrations. Mean indirect costs were also significantly lower in the methotrexate group (mean $NZ 1,141) than in the laparoscopy group (mean $NZ 1899) with a mean difference of $NZ 758 (95% CI $NZ 277 - $NZ 1,240). For women presenting with pretreatment serum beta-hCG concentrations of over 1,500 IU/ L this difference in indirect costs is lost due to the prolonged follow up required and a higher rate of surgical intervention in women receiving methotrexate. CONCLUSION: This economic evaluation shows that treating suitable women with an ectopic pregnancy using systemic methotrexate therapy results in a significant reduction in direct costs. The indirect costs borne by the woman and her carers are only likely to be reduced in women with pretreatment serum beta-hCG concentrations under 1,500 IU/L.

Pre-operative endometrial thinning agents before hysteroscopic surgery for heavy menstrual bleeding.

BACKGROUND: Menorrhagia is one of the most common reasons for pre-menopausal women to be referred to a gynaecologist. Although medical therapy is generally the first approach, many will eventually require or request a hysterectomy. Hysterectomy is associated with a significant in-patient hospital stay and a period of convalescence that makes it an unattractive and unnecessarily invasive option for many women. Hysteroscopic endometrial ablation or resection offers a day-case surgical alternative to hysterectomy for these women. It is also a cheaper procedure than hysterectomy. Complete endometrial removal or destruction is one of the most important determinants of treatment success. Therefore surgery will be most effective if undertaken when endometrial thickness is less than 4mm, in the immediate post-menstrual phase, however there are often difficulties in reliably arranging surgery for this time. The other option is the use of hormonal agents which induce endometrial thinning or atrophy prior to surgery. The most commonly evaluated agents have been goserelin (a GnRH analogue) and danazol. Progestogens and other GnRH analogues have also been studied although less data are available. It has been suggested that the use of these agents, particularly GnRH analogues, will reduce operating time, improve the intra-uterine operating environment, and reduce distension medium absorption (this is the fluid used to distend the uterine cavity during surgery). OBJECTIVES: To investigate the effectiveness of gonadotrophin-releasing hormone (GnRH) analogues, danazol, and progestogens, when used for endometrial thinning prior to hysteroscopic surgery for menorrhagia, in improving the intra-uterine operating environment and treatment outcome after surgery. SEARCH STRATEGY: The Menstrual Disorders and Subfertility Group search strategy (see Review Group details) was used to identify randomised trials that had compared the use of these drugs with either each other, or placebo, or no pre-operative treatment. SELECTION CRITERIA: Trials were included if they compared the effects of these agents with each other, or with placebo or no treatment on relevant intra-operative and post-operative treatment outcomes. Only randomised studies were included in this review. DATA COLLECTION AND ANALYSIS: Eight studies met the inclusion criteria for this review. Four studies compared goserelin (a GnRH analogue) with no treatment or placebo. Three studies compared goserelin with danazol. One study compared progestogens, danazol and triptorelin (a GnRH analogue) with no treatment. Data was extracted independently by two reviewers. A third reviewer checked data extraction for accuracy and wrote to authors where relevant data was missing or unclear. Intra-operative parameters included endometrial thickness, duration of surgery, ease of surgery, distension medium absorption and complication rate. Post-operative outcomes compared were the proportion of women with amenorrhoea, post-operative menstrual loss and dysmenorrhoea, and the need for further surgery. Data on side-effects were also recorded. MAIN RESULTS: When compared with no treatment GnRH analogues are associated with a shorter duration of surgery, greater ease of surgery and a higher rate of post-operative amenorrhoea. Post-operative dysmenorrhoea also appears to be reduced. The use of GnRH analogues has no effect on intra-operative complication rates and patient satisfaction with this surgery is high irrespective of the use of any pre-operative endometrial thinning agent. GnRH analogues produce more consistent endometrial atrophy than danazol. For other intra-operative and post-operative outcomes any differences are minimal. Both GnRH analogues and danazol produce side-effects in a significant proportion of women, though few studies have reported these in detail. Little randomised data is available to assess the effectiveness of progestogens as endometrial thinning agents and the effect of any thinning agent

Is the outcome of in-vitro fertilization and embryo transfer treatment improved by spontaneous or surgical drainage of a hydrosalpinx?

A pilot study was designed to examine whether the outcome of embryo transfer in women with a hydrosalpinx might be improved by surgical drainage of the hydrosalpinx at the time of oocyte collection for in-vitro fertilization treatment. A comparative, controlled but retrospective analysis of the results was performed of all women with infective tubal damage aged <40 years old, who had ovulatory cycles, a normal uterus and a partner with normal spermatozoa. A standardized treatment regimen was used. A maximum of three embryos were transferred. Hydrosalpinx was defined by prior hysterosalpingography and/or laparoscopy with transcervical dye injection. A total of 237 embryo transfer cycles in women with hydrosalpinges (tubal distension not visible in 151, visible but not drained in 30 and drained in 56) were compared with 705 embryo transfer cycles in women with tubal disease but no hydrosalpinx. Results were analysed in the first three cycles but also separately in the first cycle to check for bias. Success rates were higher in the first cycle, but did not significantly influence overall differences. Implantation rates were significantly reduced overall in the hydrosalpinx group (8.0 versus 13.2% for controls; P < 0.001), being 8.3% (P < 0.01) in the subgroup without evident tubal distension and 7.5% (not significant) in the drained hydrosalpinx group. This study shows that tubal damage with distal occlusion is associated with a marked reduction in embryo implantation, even in the absence of obvious fluid distension. Surgical drainage of distended hydrosalpinges appears to offer no benefit.

Delayed presentation of an extradural abscess complicating thoracic extradural analgesia.

Extradural abscess is a rare but recognized complication of extradural anaesthesia. Previous reports have been associated with a short time interval between extradural catheterization and presentation. We report a patient with rheumatoid arthritis, receiving steroid therapy, in whom an extradural abscess did not present until 23 days after the insertion of a thoracic extradural catheter to provide postoperative analgesia.

Effect of polymerization tendency on haematological, rheological and clinical parameters in sickle cell anaemia.

The polymerization tendency of sickle haemoglobin was estimated as a function of oxygen saturation in 30 patients with homozygous sickle cell anaemia. The deformability of their erythrocytes was also measured, by initial-flow-rate filtration at 37 degrees C through pores of 5 microns diameter, and clinical severity was assessed using a visual analogue scale. By means of partial correlation analysis, it was found that correlations between haematological, rheological, and clinical parameters in sickle cell anaemia could be explained on the basis of an association of each variable with polymerization tendency. Patients with the greatest tendency to form polymer had the least deformable erythrocytes and perceived their disease to be more severe as judged by the visual analogue scale. Polymer formation also appeared to be a determinant of the number of dense cells which, in turn, determine haemolytic rate and erythrocyte deformability.

Pharmacological modification of oxygen affinity improves deformability of deoxygenated sickle erythrocytes: a possible therapeutic approach to sickle cell disease.

1. The formation of polymerized haemoglobin S in sickle cells is critically dependent on the concentration of deoxygenated haemoglobin so that compounds which increase the oxygen affinity of haemoglobin S are potential anti-sickling agents. 2. BW12C [5-(2-formyl-3-hydroxyphenoxy)pentanoic acid] and BWA589C [4-(2-formyl-3-hydroxyphenoxymethyl)benzoic acid] are aromatic benzaldehydes that cause a dose-dependent left-shift of the oxygen saturation curve of haemoglobin S by stabilization of its oxy-(R)-conformation. 3. A 5 micron pore filtration method, which is highly sensitive to polymerization of haemoglobin S, was used to demonstrate a significant improvement in the deformability of deoxygenated sickle erythrocytes at concentrations (0.75-1.5 mmol/l] of BW12C and BWA589C that are achievable in vivo. Both compounds may therefore be of value for the treatment of sickle cell disease. 4. Filtration of sickle cells through pores of 5 microns diameter is a sensitive technique for evaluating the rheological effects of potential anti-sickling compounds.