Isoniazid urine spectrophotometry for prediction of serum pharmacokinetics in adults with TB

BACKGROUND

Isoniazid (INH) is an important drug in many TB regimens, and unfavorable treatment outcomes can be caused by suboptimal pharmacokinetics. Dose adjustment can be personalized by measuring peak serum concentrations; however, the process involves cold-chain preservation and laboratory techniques such as liquid chromatography (LC)/mass spectrometry (MS), which are unavailable in many high-burden settings. Urine spectrophotometry could provide a low-cost alternative with simple sampling and quantification methods.

METHODS

We enrolled 56 adult patients on treatment for active TB. Serum was collected at 0, 1, 2, 4, 6, and 8 h for measurement of INH concentrations using validated LC-MS/MS methods. Urine was collected at 0-4, 4-8, and 8-24 h intervals, with INH concentrations measured using colorimetric methods.

RESULTS

The median peak serum concentration and total serum exposure over 24 h were 4.8 mg/L and 16.4 mg*hour/L, respectively. Area under the receiver operator characteristic curves for urine values predicting a subtherapeutic serum concentration (peak <3.0 mg/L) were as follows: 0-4 h interval (AUC 0.85, 95% CI 0.7-0.96), 0-8 h interval (AUC 0.85, 95% CI 0.71-0.96), and 0-24 h urine collection interval (AUC 0.84, 95% CI 0.68-0.96).

CONCLUSION

Urine spectrophotometry may improve feasibility of personalized dosing in high TB burden regions but requires further study of target attainment following dose adjustment based on a urine threshold.

Clinical standards for the management of adverse effects during treatment for TB

BACKGROUND: Adverse effects (AE) to TB treatment cause morbidity, mortality and treatment interruption. The aim of these clinical standards is to encourage best practise for the diagnosis and management of AE.METHODS: 65/81 invited experts participated in a Delphi process using a 5-point Likert scale to score draft standards.RESULTS: We identified eight clinical standards. Each person commencing treatment for TB should: Standard 1, be counselled regarding AE before and during treatment; Standard 2, be evaluated for factors that might increase AE risk with regular review to actively identify and manage these; Standard 3, when AE occur, carefully assessed and possible allergic or hypersensitivity reactions considered; Standard 4, receive appropriate care to minimise morbidity and mortality associated with AE; Standard 5, be restarted on TB drugs after a serious AE according to a standardised protocol that includes active drug safety monitoring. In addition: Standard 6, healthcare workers should be trained on AE including how to counsel people undertaking TB treatment, as well as active AE monitoring and management; Standard 7, there should be active AE monitoring and reporting for all new TB drugs and regimens; and Standard 8, knowledge gaps identified from active AE monitoring should be systematically addressed through clinical research.CONCLUSION: These standards provide a person-centred, consensus-based approach to minimise the impact of AE during TB treatment.

Clinical standards for the dosing and management of TB drugs

BACKGROUND: Optimal drug dosing is important to ensure adequate response to treatment, prevent development of drug resistance and reduce drug toxicity. The aim of these clinical standards is to provide guidance on 'best practice´ for dosing and management of TB drugs.METHODS: A panel of 57 global experts in the fields of microbiology, pharmacology and TB care were identified; 51 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all participants.RESULTS: Six clinical standards were defined: Standard 1, defining the most appropriate initial dose for TB treatment; Standard 2, identifying patients who may be at risk of sub-optimal drug exposure; Standard 3, identifying patients at risk of developing drug-related toxicity and how best to manage this risk; Standard 4, identifying patients who can benefit from therapeutic drug monitoring (TDM); Standard 5, highlighting education and counselling that should be provided to people initiating TB treatment; and Standard 6, providing essential education for healthcare professionals. In addition, consensus research priorities were identified.CONCLUSION: This is the first consensus-based Clinical Standards for the dosing and management of TB drugs to guide clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment to improve patient care.

Impact of Cell Culture and Copper Dose on Gene Expression in Bovine Liver

The objectives of these experiments were to investigate (1) the relative abundance of transcripts for Cu-responsive genes in whole bovine liver vs. cultured hepatocytes and (2) the influence of Cu dose on the relative abundance of transcripts for Cu-responsive genes in cultured bovine hepatocytes. Experiment 1: Liver samples were obtained immediately post-mortem from one healthy Angus steer. Half of the tissue samples were placed in RNAlater solution; the remaining half was used to isolate hepatocytes. Experiment 2: A subset of cultured hepatocytes was incubated in media containing: 0 mg/L, 0.10 mg/L, 1.0 mg/L, 10.0 mg/L, and 100 mg/L Cu for 1 h. Transcripts analyzed were aldehyde dehydrogenase (ALDH2), apolipoprotein A-1 (APOA1), antioxidant 1 (ATOX1), ATPase copper transporting alpha (ATP7A), ATPase copper transporting beta (ATP7B), betaine homocysteine methyltransferase (BHMT), flavin reductase (BLVRB), carbonic anhydrase II (CA2), copper chaperone for superoxide dismutase (CCS), cytochrome c oxidase copper chaperone (COX17), Cu transporter 1 (CTR1), glutamate dehydrogenase (GLUD1), glutathione synthetase (GSS), protein disulfide isomerase A3 (PDIA3), and superoxide dismutase (Cu-Zn) (SOD1). Β-Actin (ACTB) was selected as the endogenous control in both experiments. Experiment 1: Whole liver had greater (P < 0.01) relative abundance of mRNA for APOA1, ATOX1, ATP7A, ATP7B, COX17, CTR1, ALDH2, BHMT, BLVRB, CA2, GLUD1, and GSS when compared with cultured hepatocytes. Experiment 2: Copper dose impacted all identified transcripts. These results indicate that the relative abundance of Cu-responsive transcripts is different in whole vs. cultured hepatocytes and that the relative abundance of Cu-responsive genes is dependent on Cu dose in cultured hepatocytes.

National approaches to TB care in adolescents

BACKGROUND: Adolescents bear a large burden of TB but high-prevalence countries differ significantly in their approach to address the specific needs of adolescent patients. We explore the national approaches to TB care in adolescents and compare them to the recommendations of the WHO.METHODS: We conducted a scoping review to describe the country-level guidelines to TB care in adolescents in high-burden countries. These guidelines were obtained through open sources. Information on TB care in adolescents were extracted from guidelines and compared to WHO recommendations.RESULTS: We found a lack of consensus in defining adolescents and that many national guidelines do not address the special healthcare needs of adolescents nor align with the WHO recommendations. Recently updated country guidelines are more likely to recommend short-course regimens for TB preventive treatment and countries with a higher level of income were more likely to follow WHO guidance for microbiological confirmation of TB disease in adolescents.CONCLUSION: A clear understanding of the burden of TB in adolescents that is reflected in disaggregated data reported at the country level is imperative in order to address the specific challenges to care in this high-risk group.

Outbreak of pyrazinamide-monoresistant tuberculosis identified using genotype cluster and social media analysis

SETTING

Monoresistance to pyrazinamide (PZA) has infrequently been associated with Mycobacterium tuberculosis.

OBJECTIVE

To report an outbreak of PZA-monoresistant M. tuberculosis in Virginia involving two genotype clusters from December 2004 to August 2010.

RESULTS

Thirty cases were identified involving a predominantly young, US-born population with histories of substance use and incarceration and a large proportion of children aged <15 years (n= 6, 20%); of these, 23 cases (77%) were culture-confirmed as M. tuberculosis complex. DNA fingerprinting and molecular analysis of the PZA resistance gene, pncA, demonstrated a clonal strain that was not M. bovis. Genotypic data provided the initial link between seemingly unrelated cases, and helped reveal a historic genotype cluster of cases from 2004. Further genotype cluster and contact investigation procedures, including the novel use of the social networking website Facebook.com, revealed additional links between the 2004 and 2009 genotype clusters and described an ongoing, extensive outbreak necessitating an enhanced screening and treatment protocol for contacts.

CONCLUSIONS

This outbreak demonstrates how tuberculosis can spread through a young, vulnerable population. The use of genotypic data and the novel incorporation of social media investigations were critical to understanding the settings and context of infectivity.

Pulmonary and cardiovascular responses of rats to inhalation of a commercial antimicrobial spray containing titanium dioxide nanoparticles

Our laboratory has previously demonstrated that application of an antimicrobial spray product containing titanium dioxide (TiO(2)) generates an aerosol of titanium dioxide in the breathing zone of the applicator. The present report describes the design of an automated spray system and the characterization of the aerosol delivered to a whole body inhalation chamber. This system produced stable airborne levels of TiO(2) particles with a median count size diameter of 110 nm. Rats were exposed to 314 mg/m(3) min (low dose), 826 mg/m(3) min (medium dose), and 3638 mg/m(3) min (high dose) of TiO(2) under the following conditions: 2.62 mg/m(3) for 2 h, 1.72 mg/m(3) 4 h/day for 2 days, and 3.79 mg/m(3) 4 h/day for 4 days, respectively. Pulmonary (breathing rate, specific airway resistance, inflammation, and lung damage) and cardiovascular (the responsiveness of the tail artery to constrictor or dilatory agents) endpoints were monitored 24 h post-exposure. No significant pulmonary or cardiovascular changes were noted at low and middle dose levels. However, the high dose caused significant increases in breathing rate, pulmonary inflammation, and lung cell injury. Results suggest that occasional consumer use of this antimicrobial spray product should not be a hazard. However, extended exposure of workers routinely applying this product to surfaces should be avoided. During application, care should be taken to minimize exposure by working under well ventilated conditions and by employing respiratory protection as needed. It would be prudent to avoid exposure to children or those with pre-existing respiratory disease.

Extensively drug-resistant tuberculosis in children with human immunodeficiency virus in rural South Africa

SETTING

Extensively drug-resistant tuberculosis (XDR-TB) has been documented worldwide, but reports of XDR-TB in children are extremely limited.

OBJECTIVE

To report the characteristics of pediatric XDR-TB patients in rural South Africa.

DESIGN

We retrospectively reviewed children with sputum culture-confirmed XDR-TB from Tugela Ferry, South Africa, from January 2006 to December 2007. Demographic, clinical and microbiologic data were abstracted from medical records.

RESULTS

Four children aged 6-8 years with XDR-TB were reviewed. Two had previous histories of TB. All were human immunodeficiency virus (HIV) infected orphans; three received highly active antiretroviral therapy (HAART) before XDR-TB diagnosis. All had clinical and radiographic improvement and sputum culture conversion while on standardized XDR-TB treatment and HAART. Two tolerated concomitant XDR-TB and HIV treatment well. Two experienced neuropsychiatric side effects related to cycloserine. All have survived >24 months and all were cured. Prior to XDR-TB diagnosis, the children had resided in the hospital's pediatric ward for a median of 8 months (range 5-17), including a 3-month overlapping period.

CONCLUSIONS

XDR-TB is a microbiologic diagnosis that, even with HIV co-infection, can be successfully identified. Concurrent XDR-TB and HIV therapy is feasible and effective in children, although more research is needed into potential overlapping toxicities. Nosocomial transmission is suggested, calling for infection control policies in pediatric wards.

Dose response study of subarachnoid diamorphine for analgesia after elective caesarean section

Subarachnoid diamorphine provides excellent analgesia after elective caesarean section but the optimum dose is still uncertain. We therefore investigated the effects of three regimens of subarachnoid diamorphine. Forty parturients were assigned to one of four groups. A control group received no diamorphine in their subarachnoid bupivacaine and three study groups received 0.1 mg, 0.2 mg or 0.3 mg diamorphine added to 12.5 mg hyperbaric bupivacaine 0.5% in a semi-blind randomised design study. All women received a 100 mg diclofenac suppository at the end of the caesarean section and were provided with morphine patient controlled analgesia (PCA) postoperatively. The patients were assessed for pain, morphine usage and side-effects at 2, 4, 8 and 24 h after the subarachnoid injection. Postoperative visual analogue scores for pain and PCA morphine consumption were significantly lower, and mean time to first use of morphine was significantly longer in the 0.3 mg diamorphine group. The mean (SD) dose of PCA morphine used over 24 h was 39.4 (14.7), 25.6 (16.5), 21.6 (15.9) and 3.1 (3.6) mg, and mean time to first use of morphine was 1.6 (0.5), 3.0 (1.4), 3.4 (2.4) and 14.1 (9.4) h, in the 0, 0.1 mg, 0.2 mg and 0.3 mg groups respectively. Side-effects of pruritus, nausea and vomiting were dependent on the dose of spinal diamorphine but did not require treatment in any patients. We conclude that 0.3 mg subarachnoid diamorphine provides significantly better postoperative pain relief than the smaller doses with an acceptable increase in side-effects.

Maternal deaths from anaesthesia. An extract from Why mothers die 1997-1999, the Confidential Enquiries into Maternal Deaths in the United Kingdom

This article is reprinted from Why Mothers Die 1997-1999, the fifth report of the Confidential Enquiries into Maternal Deaths in the United Kingdom.

An analysis of limb-threatening lower extremity wound complications after 1090 consecutive coronary artery bypass procedures

The objective of this study was to examine and characterize limb-threatening lower extremity wound or soft tissue complications after coronary artery bypass (CABG) and determine risk factors for their cause. While minor wound problems of the leg after CABG are not uncommon, serious limb-threatening complications, though less frequent, do occur and are often de-emphasized in the surgical literature. A review of 1090 consecutive CABG procedures performed from January 1, 1995 through December 31, 1995 was instituted, which screened for limb-threatening lower extremity wound or soft tissue complications defined as wounds that: required additional surgery for treatment; prolonged the length of stay; or which required lengthy home health nursing for treatment. Minor lymph leaks, leg swelling, infections or wound problems treated as an outpatient were excluded. Of 1090 patients, 54 (5.0%) experienced a limb-threatening lower extremity complication. Complications were categorized as vein harvest incision non-healing (n = 36, 66.7%), decubitus ulceration (n = 11, 20.4%), forefoot ischemia/embolization (n = 10, 18.5%), groin hematoma/abscess (n = 6, 11.1%), severe cellulitis (n = 3, 5.6%), or a combination (n = 12, 22.2%). Statistically significant risk factors by univariate and bivariate analysis for a complication included older age (68 years vs 62 years, p = 0.007), female sex (57% vs 28%, p < 0.001), diabetes (57% vs 33%, p = 0.005) and longer pump time (129 min vs 114 min, p = 0.009). These complications necessitated five major lower extremity amputations and nine revascularization procedures. Chronic lower extremity ischemia from peripheral vascular disease (PVD) was a major contributing factor for the development of wounds in at least 23 (42.6%) of these patients, though suspected in only 10 (43.5%) preoperatively. A non-healing vein harvest incision below the knee of a patient retrospectively found to have inadequate distal circulation for healing occurred in 17 (31.5%) of the total 54 cases. It was concluded that non-healing vein incisions, decubitus ulcers and forefoot ischemic lesions frequently occurring in older diabetic females with undetected pre-existing PVD, comprise the majority of limb-threatening leg complications after CABG. Nearly one-third of the complications may have been avoided had the vein harvest incision not been made at the ankle of a patient with unappreciated PVD.

Alternative operative techniques in laparoscopic Roux-en-Y gastric bypass for morbid obesity

The only effective treatment for patients with morbid obesity is surgery. Laparoscopic bariatric surgery has become quite popular in attempts to decrease the morbidity associated with laparotomy. In this article, we describe the technical details of laparoscopic Roux-en-Y gastric bypass with three different techniques for creating the 15-cc gastric pouch. These techniques avoid upper endoscopy for the transoral introduction of the 21-mm circular stapler anvil down to the gastric pouch.

Randomized study of intravenous fluid preload before epidural analgesia during labour

We performed a randomized controlled trial of the effect of intravenous fluid preload on maternal hypotension and fetal heart rate (FHR) changes in labour after the first epidural injection. Group 1 (49 women) received 1 litre of crystalloid preload. Group 2 (46 women) received no preload. No statistically significant difference was shown between the two groups for either of the outcomes. Hypotension was found in three women in group 1 and five in group 2 (P = 0.4). Deterioration in FHR pattern was found in four women in group 1 and 11 in group 2 (P = 0.08). This study has not shown a significant increase in the incidence of hypotension when intravenous preload is omitted before epidural analgesia using a low concentration of bupivacaine during labour. Because of the clinical importance of the difference in the rate of FHR deterioration between the two groups, we continue to administer preload for high-risk cases.

An alternative technique for creating the gastrojejunostomy in laparoscopic Roux-en-Y gastric bypass: experience with 28 consecutive patients

BACKGROUND

This study illustrates our experience in laparoscopic Roux-en-Y gastric bypass (LRYGBP) using a new technique for creating the gastro-jejunostomy.

METHODS

Between April and November 1999, 28 patients underwent LRYGBP. In the first 10 patients the transoral route with endoscopic guidance was utilized for placement of the anvil in the gastric pouch. A new totally intra-peritoneal approach was utilized in the next 18 patients, avoiding the trans-oral route.

RESULTS

There were 23 women and 5 men with an average age of 36 years (range 24-51). The mean BMI was 47, with range 41-64. Of the patients, 82% had one or more associated co-morbid conditions (hypertension, diabetes, sleep apnea, arthritis). Average operative time in the first 10 patients using the trans-oral route with endoscopic guidance was 340 minutes (range 240-390 min). The next 18 patients underwent totally intra-peritoneal anvil placement with a 240-minute average operating time (range 150-310 min). There were no open conversions or mortalities. There were 4 complications, including 2 wound infections, one urinary tract infection, and one intra-abdominal abscess. The two wound infections occurred in the first 10 patients that underwent trans-oral introduction of the anvil.

CONCLUSIONS

LRYGBP was a safe and feasible operation. We believe that our technique is easily reproducible, avoiding the trans-oral route for introducing the anvil. This technique may also decrease operative time and possibly the incidence of wound infections, although we are still in the learning curve and final conclusions cannot be made.

Schemes for the identification of tissue types and boundaries at the tool point for surgical needles

Precise control of automated invasive surgical tools requires real-time identification of tissue types and their deformation. At the focus of this paper is the epidural puncture, for which it is shown that the tissue type and deformation can respectively be determined from laser-based spectroscopy and the change in force required to push the needle through the various tissues. Studies have shown that physiological variations from one patient to another are too great to allow absolute values to be reliably used to indicate the position of the needle tip. However, the pattern of force variation during penetration is shown to be similar between specimens. Interpretation of this information in conjunction with spectroscopic techniques can be used to discriminate between tissues and tissue structure at the needle tip. This paper describes results from an investigation on automatic techniques for interpreting the type and deformation of tissues under tool action.

A novel genotype encoding a single amino acid insertion and five other substitutions between residues 64 and 74 of the HIV-1 reverse transcriptase confers high-level cross-resistance to nucleoside reverse transcriptase inhibitors. Abacavir CNA2007 International Study Group

We investigated HIV-1 reverse transcriptase (RT) polymorphisms of plasma isolates from 98 HIV-1-infected study subjects with >2 years of antiretroviral therapy who were failing their current protease inhibitor (PI)-containing regimen. In 1 patient, we detected a virus with a heavily mutated beta3-beta4 connecting loop of the HIV-1 RT fingers subdomain, consisting of a single aspartate codon insertion between positions 69 and 70 and five additional variations: 64N, K65, K66, 67G, 68Y, T69, Ins D, 70R, W71, R72, K73, 74I. Mutants with the recently described 2-aa insertions between codons 68 and 70 of RT were detected in another 3 patients. Among the four isolates with the 1- or 2-aa insertions, the novel genotype was the most refractory to therapy and displayed the highest level of phenotypic resistance to nucleoside reverse transcriptase inhibitors (NRTIs). Follow-up samples demonstrated that the novel mutant represents a stable genetic rearrangement and that the amino acid insertions can coexist with nonnucleoside analogue reverse transcriptase inhibitors (NNRTI) mutations resulting in phenotypic resistance to both NRTIs and NNRTIs. An increasing number of HIV-1 isolates containing various insertions in the beta3-beta4 hairpin of the HIV-1 RT fingers subdomain appear to emerge after prolonged therapy with different NRTIs, and these polymorphisms can confer multiple drug resistance against NRTIs.

The Abuela Project: safe cheese workshops to reduce the incidence of Salmonella typhimurium from consumption of raw-milk fresh cheese

OBJECTIVES

A multiagency intervention was implemented in Yakima County, Wash, to reduce the incidence of Salmonella serotype Typhimurium infections resulting from eating queso fresco (fresh cheese) made from raw milk, a traditional food in the Hispanic diet.

METHODS

A pasteurized-milk queso fresco recipe with taste and texture acceptable to the Hispanic community was developed. Trained Hispanic volunteers conducted safe cheese workshops, which were attended by more than 225 persons.

RESULTS

Workshop participants' acceptance of the new recipe was excellent and positive behavior changes were maintained over 6 months.

CONCLUSIONS

Educational interventions in Hispanic communities can reduce the incidence of Salmonella Typhimurium associated with eating queso fresco.

The influence of timing of ketorolac administration on post-operative analgesic requirements following total abdominal hysterectomy

One hundred and thirty-seven patients were studied to assess whether the timing of a dose of ketorolac affected cumulative morphine requirements during the first 12 post-operative hours. Pain, sedation and nausea scores, respiratory rate and degree of operative blood loss were also recorded. Thirty-six patients (group A) were given placebo injections pre- and intra-operatively. Thirty-one patients (group B) received placebo pre-operatively and ketorolac 30 mg intra-operatively. Thirty-six patients (group C) received ketorolac 10 mg pre-operatively and ketorolac 20 mg intra-operatively and thirty-four patients (group D) were given ketorolac 30 mg pre-operatively and placebo intra-operatively. Post-operative analgesia was with intravenous (i.v.) morphine administered using a patient controlled analgesia (PCA) device. Analysis of variance revealed a significant difference in morphine consumption at 1, 2, 4, 8 and 12 h postoperatively (P < 0.05) between group A (no ketorolac) and groups B, C and D (ketorolac). However, there were no significant differences between groups B, C and D during the study period. Thus, the timing of ketorolac administration made no difference to overall morphine consumption. Pain, nausea, sedation and respiratory rate scores were similar in all four groups. There was a significantly greater blood loss in patients receiving ketorolac (groups B, C and D) compared with those receiving placebo alone (group A).

Simulation of resistance forces acting on surgical needles

High precision in the manual control of needles and biopsy probes in medical treatment requires high skill and dexterity levels. In anaesthesia, force sensation is an important feedback mechanism, and the practitioner needs to refresh or develop skills to improve on the interpretation of needle progress towards the target site. This paper describes an experimental tactile force simulator for uniaxial needle action for which the force resisting progress of the needle is derived from measured data. As an example, the approach taken to develop the simulation of the insertion of epidural needles is described. Adaptation to other procedures would be possible by adopting new reference models based on appropriate measured force data.

Epidural infusions of bupivacaine and diamorphine in labour

Three different concentrations of bupivacaine, 0.125%, 0.062% and 0.031%, all with diamorphine 0.0025%, were given as an epidural infusion at 10 ml.h-1 to 63 mothers in labour. When the three infusions were compared, significant differences were found in maternal requirements for top-ups and the degree of motor block, but there were no differences in the pain scores. The reduced motor block was not associated with a reduction in the instrumental delivery rate.

Overpressure isoflurane at caesarean section: a study of arterial isoflurane concentrations

In this study we have measured arterial concentrations of isoflurane obtained during Caesarean section in two groups of patients. Patients in group 1 received 1% isoflurane throughout operation, whilst those in group 2 received 2% isoflurane for the first 5 min, 1.5% for the next 5 min and 0.8% thereafter. We found that arterial isoflurane concentrations were significantly greater in group 2 than in group 1 (ANOVA, P < 0.05). Isoflurane concentrations greater than 30 micrograms ml-1 were achieved rapidly in most patients in both groups, but there was a large scatter of results. The isoflurane concentration at which awareness or recall may occur is not known, but an "overpressure" technique as described for patients in group 2 may result in fewer patients being at risk of awareness.

Isoflurane in labour

A comparison of the analgesic efficacy of Entonox (50% nitrous oxide in oxygen) and Entonox with 0.2% isoflurane was made in 18 consenting mothers during the first stage of labour. The inhalational gases were self-administered during contractions over a 3 h study period using a standard Entonox demand valve and breathing system. Isoflurane 0.2% was added from an Ohmeda Isotec drawover vaporizer and the inspired concentration of isoflurane was analysed continuously using a Datex Ultima analyser. Linear analogue scores for pain were significantly lower (p < 0.001) during the Entonox-isoflurane administration compared with Entonox alone. Drowsiness was not a clinical problem and there was a high acceptance rate for Entonox-isoflurane inhalational analgesia during labour.

Comparison of automatic oscillometric arterial pressure measurement with conventional auscultatory measurement in the labour ward

We have compared two non-invasive methods of arterial pressure (AP) measurement used in labour wards: an automatic oscillometric measurement obtained by Dinamap 1846, and a conventional auscultatory measurement obtained by midwives. A total of 369 AP measurements were recorded, involving 28 normotensive and hypertensive pregnant women during labour, with or without extradural analgesia. Compared with the midwife group, the Dinamap group had a greater systolic AP, by 2.7 mm Hg (P < 0.01) and smaller diastolic AP, by 9.8 mm Hg (P < 0.01). The correlations between the two methods were highly significant, but the limits of agreement were relatively wide for both systolic and diastolic AP measurements. We conclude that a clinically important difference exists in diastolic AP measurements. Dinamap diastolic AP must be corrected using a regression equation, or simply by adding 10 mm Hg, before being compared with the available normal and hypertensive AP values.

Spinal anaesthesia for caesarean section: comparison of 22-gauge and 25-gauge Whitacre needles with 26-gauge Quincke needles

We have studied 150 women undergoing elective Caesarean section under spinal anaesthesia. They were allocated randomly to have a 22-gauge Whitacre, a 25-gauge Whitacre or a 26-gauge Quincke needle inserted into the lumbar subarachnoid space. The groups were compared for ease of insertion, number of attempted needle insertions before identification of cerebrospinal fluid, quality of subsequent analgesia and incidence of postoperative complications. There were differences between groups, but they did not reach statistical significance. Postdural puncture headache (PDPH) was experienced by one mother in the 22-gauge Whitacre group, none in the 25-gauge Whitacre group and five in the 26-gauge Quincke group. Five of the six PDPH occurred after a single successful needle insertion. Seven of the 15 mothers in whom more than two needle insertions were made experienced backache, compared with 12 of the 129 receiving two or less (P < 0.001). We conclude that the use of 22- and 25-gauge Whitacre needles in elective Caesarean section patients is associated with a low incidence of PDPH and that postoperative backache is more likely when more than two attempts are made to insert a spinal needle.

Epidural bupivacaine dilution for labour. A comparison of three concentrations infused with a fixed dose of fentanyl

We have compared the effects of three epidural infusions in a randomised, double-blind study of 56 primigravid mothers in labour. An initial dose of bupivacaine 0.5% 8 ml was followed by infusion of either bupivacaine 0.125%, 0.062% or 0.031%. All solutions contained fentanyl 0.0002% and were run at 7.5 ml/hour. Women receiving the most dilute solution had significantly less analgesia (p less than 0.001) for the first 4 hours of the study, but pain scores were then similar for the three groups. No obvious benefit was gained by using very dilute bupivacaine.

Epidural infusion of diamorphine with bupivacaine in labour. A comparison with fentanyl and bupivacaine

We have compared the analgesic effects of three epidural infusions in a randomised, double-blind study of 61 mothers in labour. An initial dose of bupivacaine 0.5% 8 ml was followed by either bupivacaine 0.125%, bupivacaine 0.125% with diamorphine 0.0025% or bupivacaine 0.125% with fentanyl 0.0002%. All infusions were run at a rate of 7.5 ml/hour. Analgesia was significantly better in both the groups receiving opioids. Diamorphine was shown to be the more effective supplement to bupivacaine. The 5% incidence of pruritus in the opioid groups was less than that reported by earlier authors.

Maternal inspired oxygen concentration and neonatal status for caesarean section under general anaesthesia. Comparison of effects of 33% or 50% oxygen in nitrous oxide

The relationship between maternal FIO2 and umbilical venous PO2, PCO2, pH and neonatal Apgar and TSR (time to sustained respiration) scores was studied in 35 patients undergoing Caesarean section under general anaesthesia. Patients were allocated randomly to breathe an FIO2 of either 0.5 or 0.33. Umbilical venous blood was collected at the time of delivery, and TSR and 1- and 5-min Apgar scores recorded. Mean values for umbilical venous blood were: PO2 3.9 kPa and 3.7 kPa; PCO2 6.2 kPa and 6.2 kPa; pH 7.30 and 7.31 (50% and 33% groups, respectively (P greater than 0.05]. No differences were found between groups for 1- or 5-min Apgar scores or TSR values. It is concluded that no difference in fetal outcome or acid-base status can be detected when maternal FIO2 is decreased from 0.5 to 0.33, and that the use of 33% oxygen in 66% nitrous oxide appears to be safe for neonates who have not suffered fetal distress before delivery.

Posture and post-spinal headache. A controlled trial in 80 obstetric patients

Eighty obstetric patients receiving subarachnoid anaesthesia for second and third stage procedures, excluding Caesarean section, were studied. They were randomly allocated postpartum to either 24 h bed rest or early (6 h post spinal) mobilization. Patients were followed up at 48 h post-partum and the incidence and severity of post-spinal headache noted. There was a significantly greater incidence of severe spinal headaches in the "bed-rest" group and three patients in this group required blood patch treatment for their headache. Early mobilization is, therefore, the recommended management after spinal anaesthesia for these types of obstetric procedure.

Prescribing for labour

Prostaglandins, particularly PGE2 vaginally, can be valuable for cervical ripening or induction of labour in some women. Ease of use must not be allowed to result in unjustified intervention. Amniotomy followed by oxytocin infusion are the methods of choice for induction of labour. Careful monitoring of the maternal and fetal condition are vital, especially if an epidural block is in place. Augmentation of labour is only appropriate for inefficient primigravid labour. Failure to progress in a multiparous woman is more likely to be due to obstruction. Low residue, easily digested foodstuffs are not necessarily contraindicated during normal labour. When properly used, Entonox can provide analgesia equivalent to 75-100 mg pethidine. Sodium citrate is the antacid of choice during labour and should be combined with an H2-receptor blocking agent for caesarean section, or other procedure involving anaesthesia. The routine injection of Syntometrine at delivery of the anterior shoulder to prevent PPH is widespread in the UK but has not been properly tested. Oxytocics are invaluable in the treatment of PPH.

A method for producing normocarbia during general anaesthesia for caesarean section

Twenty-six patients were anaesthetised for Caesarean section using the Bain anaesthetic system for intermittent positive pressure ventilation. There was an inverse relationship between maximum end tidal carbon dioxide tension and the fresh gas flow (FGF) to the system. A significant difference existed between the patients receiving 80 ml/kg/min FGF and those receiving 120 ml/kg/min. Estimated carbon dioxide levels in the pregnant term patient were higher at each FGF rate than the levels reported in non-pregnant patients by other workers. In order to maintain maternal arterial carbon dioxide tension at or close to the normally quoted term value of 4.1-4.4 kPa, when using positive pressure ventilation with a Bain system, a fresh gas flow rate of at least 120 ml/kg body weight/minute is required.

Second stage of labour with or without extradural analgesia

Two groups of parturients who had received selective extradural analgesia were studied. In Group A patients the regional block was allowed to wear off for the second stage of labour whereas in Group B patients' analgesia was maintained throughout labour. The maintenance of selective analgesia was of positive benefit to the mothers. They experienced much less pain, labour was not prolonged, dosage of bupivacaine was not increased, the forceps delivery rate was lower and there were fewer persistent malrotations.

An investigation into opioid systems in the pregnant rat

The role of opioid peptides during pregnancy and parturition has not been defined. They may function as natural analgesics during parturition. Pain thresholds were tested during pregnancy but, in contrast with a previous study, were found not to change. Plasma Beta-endorphin-like-immunoreactivity (B-ELI) was measured and towards the end of pregnancy a significant increase was recorded. Peptide levels returned to the pre-gestational concentration just prior to parturition. Pituitary B-ELI was also measured and was only significantly raised on the day before expected parturition. These changes add to the evidence that opioid peptides have a physiological function during pregnancy and parturition.

Influence of medication, pain and progress in labour on plasma beta-endorphin-like immunoreactivity

Plasma beta-endorphin-like immunoreactivity (beta-ELI) was measured at intervals during labour in 42 patients. An increase in beta-ELI occurred during labour and increased to a maximum during the second stage. The increase in beta-ELI paralleled dilatation of the cervix. A correlation existed between the duration of labour and second stage beta-ELI in patients with labours of more than 4 h duration. Analgesic drugs were associated with changes in beta-ELI. The patients who received Entonox had greater plasma beta-ELI concentrations than those who received pethidine. A significant difference in the second stage beta-ELI existed between those who received only Entonox and those who received only pethidine. Induction and augmentation of labour were also associated with differences in beta-ELI. Patients in spontaneous labour had significantly lower beta-ELI than patients who had either artificial rupture of membranes or Syntocinon augmentation of labour.

Cardiovascular changes during laparoscopy. Studies of stroke volume and cardiac output using impedance cardiography

The stroke volume and cardiac output changes in twenty-four patients undergoing laparoscopy were measured using the non-invasive technique of impedance cardiography. There was a moderate fall of stroke volume and cardiac output during intraperitoneal insufflation of carbon dioxide which was directly related to the volume of gas used. The need for caution during laparoscopy particularly in ill patients is emphasised.