Hyponatraemia reversibly affects human myometrial contractility. An in vitro pilot study.

BACKGROUND: In a previous study we found a significant correlation between dystocia and hyponatraemia that developed during labour. The present study examined a possible causal relationship. In vitro studies often use area under the curve (AUC) determined by frequency and force of contractions as a measure of myometrial contractility. However, a phase portrait plot of isometric contraction, obtained by plotting the first derivate of contraction against force of contraction, could indicate that bi-or multiphasic contractions might be less effective compared to the smooth contractions. MATERIAL AND METHODS: Myometrial biopsies were obtained from 17 women undergoing elective caesarean section at term. Each biopsy was divided into 8 strips and mounted isometrically in a force transducer. Seven biopsies were used in the first part of the study when half of the strips were immersed in the hyponatraemic study solution S containing Na+ 120 mmol/L and observed for 1 hour, followed by 1 hour in normonatraemic control solution C containing Na+ 136 mmol/L, then again in S for 1 hour, and finally 1 hour in C. The other half of the strips were studied in reverse order, C-S-C-S. The remaining ten biopsies were included in the second part of the study. Response to increasing doses of oxytocin (OT) in solutions S and C was studied. In the first part of the study we calculated AUC, and created phase portrait plots of two different contractions from the same strip, one smooth and one biphasic. In both parts of the study we registered frequency and force of contractions, and described appearance of the contractions. RESULTS: First part of the study: Mean (median) contractions per hour in C: 8.7 (7.6), in S 14,3 (13). Mean (SD) difference between groups 5.6 (4.2), p = 0.018. Force of contractions in C: 11.8 (10.2) mN, in S: 10.8 (9.2) mN, p = 0.09, AUC increased in S; p = 0.018. Bi-/multiphasic contractions increased from 8% in C to 18% in S, p = 0.001. All changes were reversible in C. Second part of the study: Frequency after OT 1.65 x 10-9 M in C:3.4 (2.9), in S: 3.8 (3.2), difference between groups: p = 0.48. After OT 1.65 x 10-7 M in C: 7.8 (8.9), increase from previous OT administration: p = 0.09, in S: 8.7 (9.0), p = 0.04, difference between groups, p = 0.32. Only at the highest dose of OT dose was there an increase in force of contraction in S, p = 0.05, difference between groups, p = 0.33. Initial response to OT was more frequently bi/multiphasic in S, reaching significance at the highest dose of OT(1.65 x 10-7 M), p = 0.015. when almost all contractions were bi/multiphasic. CONCLUSION: Hyponatraemia reversibly increased frequency of contractions and appearance of bi-or multiphasic contractions, that could reduce myometrial contractility. This could explain the correlation of hyponatraemia and instrumental delivery previously observed. Contractions in the hyponatraemic solution more frequently showed initial multiphasic contractions when OT was added in increasing doses. Longer lasting labours carry the risk both of hyponatraemia and OT administration, and their negative interaction could be significant. Further studies should address this possibility.

Feto-maternal osmotic balance at term. A prospective observational study.

OBJECTIVE: We performed the present study to investigate the feto-maternal osmotic relationship at term with the hypothesis that, in contrast to the literature, maternal plasma osmolality is lower than fetal levels. In a previous study, we found that maternal plasma sodium at delivery was consistently lower than the sodium in the umbilical artery. Our aim was to corroborate these results with analysis of osmolality. METHODS: Blood was sampled from 30 women immediately before cesarean section and from the umbilical artery and vein before cord clamping and osmolality, sodium and albumin were analyzed. RESULTS: Maternal osmolality was (mean; 95% confidence interval) 287.0 (285.8-288.2) mOsmkg/kg, arterial cord osmolality was 289.4 (287.9-291.0) mOsm/kg and venous cord osmolality was 287.3 (286.0-288.5) mOsm/kg. The paired difference between maternal and umbilical arterial osmolality was mean (SD) -2.4 (3.3) mOsm/kg (P<0.001), between maternal and umbilical vein -0.3 (3.0) mOsm/kg (P=0.63) and between umbilical artery and vein -2.1 (2.8) mOsm/kg (P<0.001). CONCLUSION: Maternal osmolality was significantly lower than arterial cord osmolality confirming our previous results. The feto-maternal osmotic gradient favors water transport from the mother to the fetus and may increase the fetal risk of water intoxication when the mother ingests or is administered large volumes of electrolyte free solutions.

[The impact of an Anaesthesia and Intensive Care collaboration between Sweden and Tanzania]. / Samarbete Tanzania-Sverige för bättre anestesi och intensivvård - 22 anestesiologer på 47 miljoner tanzanier men nu börjar samarbetsprojektet ge resultat.

The impact of an Anaesthesia and Intensive Care collaboration between Sweden and Tanzania Anaesthesia and intensive care is a neglected specialty in low-income countries. Many countries have less than 1 anaesthesia provider per 100,000 population and few hospitals in Africa have the resources for managing critically ill patients. Health partnerships between institutions in high- and low-income countries have been proposed as an effective way to strengthen health systems. This article describes a partnership in anaesthesia and intensive care between institutions in Sweden and Tanzania and its impact at regional and national levels. The partnership, initiated in 2008 on the request of Muhimbili National Hospital in Dar es Salaam, conducts training, exchanges, research, equipment, routines and guidelines projects. Through the newly formed Life Support Foundation, the partnership has expanded to all hospitals in Dar es Salaam, has assisted in the reactivation of the Society of Anaesthesiologists of Tanzania and has seen a marked increase in the number of trainee doctors.

Establishing an Anaesthesia and Intensive Care partnership and aiming for national impact in Tanzania.

Anaesthesia and Intensive Care is a neglected specialty in low-income countries. There is an acute shortage of health workers - several low-income countries have less than 1 anaesthesia provider per 100,000 population. Only 1.5% of hospitals in Africa have the intensive care resources needed for managing patients with sepsis. Health partnerships between institutions in high and low-income countries have been proposed as an effective way to strengthen health systems. The aim of this article is to describe the origin and conduct of a health partnership in Anaesthesia and Intensive Care between institutions in Tanzania and Sweden and how the partnership has expanded to have an impact at regional and national levels.The Muhimbili-Karolinska Anaesthesia and Intensive Care Collaboration was initiated in 2008 on the request of the Executive Director of Muhimbili National Hospital in Dar es Salaam. The partnership has conducted training courses, exchanges, research projects and introduced new equipment, routines and guidelines. The partnership has expanded to include all hospitals in Dar es Salaam. Through the newly formed Life Support Foundation, the partnership has had a national impact assisting the reanimation of the Society of Anaesthesiologists of Tanzania and has seen a marked increase of the number of young doctors choosing a residency in Anaesthesia and Intensive Care.

Quality of anaesthesia for Caesarean sections: a cross-sectional study of a university hospital in a low-income country.

OBJECTIVE: To evaluate the quality of anaesthesia for Caesarean sections at Muhimbili National Hospital, Dar es Salaam, Tanzania. METHOD: We developed an instrument consisting of 40 quality indicators using an expert group process based on the existing literature. Using the instrument, we observed 50 Caesarean sections. Twenty-eight of the indicators were structural indicators, such as essential drugs, oxygen supply and anaesthetic equipment. Twelve were process indicators such as evaluation of airway, blood pressure assessment or insertion of an intravenous line. RESULTS: The median patient age was 28.5 years. A total of 75% (range 61-82%) of the structural indicators were present in the operating theatres, and 55% (range 33-83%) of the process indicators were performed. The neonates' median Apgar score was 9 (range 3-10). Seven babies required ventilation, four babies were stillborn, and all others were alive at follow-up 2 days after partus. All mothers were alive 2 days post-surgery. CONCLUSION: The low process score suggests that quality improvement initiatives should focus on the processes of anaesthesia for Caesarean sections rather than new drugs and equipment.

Osmolality and respiratory regulation in humans: respiratory compensation for hyperchloremic metabolic acidosis is absent after infusion of hypertonic saline in healthy volunteers.

BACKGROUND: Several animal studies show that changes in plasma osmolality may influence ventilation. Respiratory depression caused by increased plasma osmolality is interpreted as inhibition of water-dependent thermoregulation because conservation of body fluid predominates at the cost of increased core temperature. Respiratory alkalosis, on the other hand, is associated with a decrease in plasma osmolality and strong ion difference (SID) during human pregnancy. We investigated the hypothesis that osmolality would influence ventilation, so that increased osmolality will decrease ventilation and decreased osmolality will stimulate ventilation in both men and women. METHODS: Our study participants were healthy volunteers of both sexes (ASA physical status I). Ten men (mean 28 years; range 20-40) and 9 women (mean 33 years; range 22-43) were included. All women participated in both the follicular and luteal phases of the menstrual cycle. Hyperosmolality was induced by IV infusion of hypertonic saline 3%, and hypoosmolality by drinking tap water. Arterial blood samples were collected for analysis of electrolytes, osmolality, and blood gases. Sensitivity to CO2 was determined by rebreathing tests performed before and after the fluid-loading procedures. RESULTS: Infusion of hypertonic saline caused hyperchloremic metabolic acidosis with decreased SID in all subjects. Analysis of pooled data showed absence of respiratory compensation. Baseline arterial PCO2 (PaCO2) mean (SD) 37.8 (2.9) mm Hg remained unaltered, with lowest PaCO2 37.8 (2.9) mm Hg after 100 minutes, P = 0.70, causing a decrease in pH from mean (SD) 7.42 (0.02) to 7.38 (0.02), P < 0.001. Metabolic acidosis was also observed during water loading. Pooled results show that PaCO2 decreased from 38.2 (3.3) mm Hg at baseline to 35.7 (2.8) mm Hg after 80 minutes of drinking water, P = 0.002, and pH remained unaltered: pH 7.43 (0.02) at baseline to pH 7.42 (0.02), P = 0.14, mean difference (confidence interval) = pH -0.007 (-0.017 to 0.003). CONCLUSIONS: Our results indicate that osmolality has an influence on ventilation. Respiratory compensation for hyperchloremic metabolic acidosis was suppressed during hyperosmolality. Water loading caused a decrease in plasma osmolality and metabolic acidosis, and although the decrease in SID was smaller compared with salt loading, the expected respiratory compensation was observed. Ventilation was also stimulated in men, therefore independently of progesterone levels. We propose that the influence of osmolality on ventilation consists mainly as depression in conditions of hyperosmolality and that this depression is absent during hypoosmolality.

Emergency and critical care services in Tanzania: a survey of ten hospitals.

BACKGROUND: While there is a need for good quality care for patients with serious reversible disease in all countries in the world, Emergency and Critical Care tends to be one of the weakest parts of health systems in low-income countries. We assessed the structure and availability of resources for Emergency and Critical Care in Tanzania in order to identify the priorities for improving care in this neglected specialty. METHODS: Ten hospitals in four regions of Tanzania were assessed using a structured data collection tool. Quality was evaluated with standards developed from the literature and expert opinion. RESULTS: Important deficits were identified in infrastructure, routines and training. Only 30% of the hospitals had an emergency room for adult and paediatric patients. None of the seven district and regional hospitals had a triage area or intensive care unit for adults. Only 40% of the hospitals had formal systems for adult triage and in less than one third were critically ill patients seen by clinicians more than once daily. In 80% of the hospitals there were no staff trained in adult triage or critical care. In contrast, a majority of equipment and drugs necessary for emergency and critical care were available in the hospitals (median 90% and 100% respectively. The referral/private hospitals tended to have a greater overall availability of resources (median 89.7%) than district/regional hospitals (median 70.6). CONCLUSIONS: Many of the structures necessary for Emergency and Critical Care are lacking in hospitals in Tanzania. Particular weaknesses are infrastructure, routines and training, whereas the availability of drugs and equipment is generally good. Policies to improve hospital systems for the care of emergency and critically ill patients should be prioritised.

Changes in uterine innervation in pregnancy and during labour.

PURPOSE OF REVIEW: The present review highlights recent findings focusing on effects on the cervical innervation exerted by term pregnancy and labour. RECENT FINDINGS: The corpus uteri is almost denervated in term pregnancy, as demonstrated in both humans and rodents, whereas the cervical innervation remains dense throughout pregnancy and labour. In rats, fewer connections between sensory subdivisions in spinal cord segments and the cervix have been observed in late pregnancy as compared with the nonpregnant state. In term pregnancy an increased excitability of mechanosensitive afferents innervating the cervix has been demonstrated. The reasons for these seemingly contradictory findings may be clarified in further studies. Transient receptor potential vanilloid receptor, a key molecule in nociception, has been identified in the human cervix uteri in the nonpregnant state and during pregnancy and labour as opposed to the corpus, in which transient receptor potential vanilloid receptor disappears during pregnancy. These findings add evidence to the hypothesis that the uterine cervix is the main site from where labour pain propagates. SUMMARY: The conservation of the cervical innervation in term pregnancy and labour, in contrast to the corpus, and the large number of mediators involved in cervical ripening clearly indicate that the cervix plays a crucial role in pregnancy maintenance, labour initiation, labour pain and parturition.

Neurological complications following central neuraxial blockades in obstetrics.

PURPOSE OF REVIEW: The last few decades have seen an increased use of central neuraxial blockades in obstetric patients. Central blockades provide excellent labour analgesia and safe anaesthesia for caesarean section associated with low incidence of severe complications. Therefore, an increasing number of blockades are also performed in women affected by significant disease. The risks and benefits of central blockades, however, might differ in these patients. This review addresses the risks of neurological complications following central neuraxial blockades in healthy parturients as well as in women affected by significant haemostatic and neurological disease. RECENT FINDINGS: The low risk of complications following central neuraxial blockades applies primarily to women in developed countries. Infectious complications and in particular meningitis still occur, and more frequently so in developing countries. Judicious application of central blockades in women affected by neurological and haemostatic disorders may enhance patient satisfaction without increasing the risk for complications. SUMMARY: Estimation of the incidence of neurological complications following central neuraxial blockades to women affected by significant disease on the basis of case reports and small series of patients is impossible. Prospective registration of high-risk patients may increase our knowledge. Application of central neuraxial blockade must follow individual evaluation.

Influence of pregnancy and labor on the occurrence of nerve fibers expressing the capsaicin receptor TRPV1 in human corpus and cervix uteri.

BACKGROUND: Cervical ripening is a prerequisite for a normal obstetrical outcome. This process, including labor, is a painful event that shares features with inflammatory reactions where peripheral nociceptive pathways are involved. The capsaicin and heat receptor TRPV1 is a key molecule in sensory nerves involved in peripheral nociception, but little is known regarding its role in the pregnant uterus. Therefore, the aim of this study was to investigate human corpus and cervix uteri during pregnancy and labor and non-pregnant controls for the presence of TRPV1. METHODS: We have investigated human uterine corpus and cervix biopsies at term pregnancy and parturition. Biopsies were taken from the upper edge of the hysterotomy during caesarean section at term (n = 8), in labor (n = 8) and from the corresponding area in the non-pregnant uterus after hysterectomy (n = 8). Cervical biopsies were obtained transvaginally from the anterior cervical lip. Serial frozen sections were examined immunohistochemically using specific antibodies to TRPV1 and nerve markers (neurofilaments/peripherin). RESULTS: In cervix uteri, TRPV1-immunoreactive fibers were scattered throughout the stroma and around blood vessels, and appeared more frequent in the sub-epithelium. Counts of TRPV1-immunoreactive nerve fibers were not significantly different between the three groups. In contrast, few TRPV1-immunoreactive fibers were found in nerve fascicles in the non-pregnant corpus, and none in the pregnant corpus. CONCLUSION: In this study, TRPV1 innervation in human uterus during pregnancy and labor is shown for the first time. During pregnancy and labor there was an almost complete disappearance of TRPV1 positive nerve fibers in the corpus. However, cervical innervation remained throughout pregnancy and labor. The difference in TRPV1 innervation between the corpus and the cervix is thus very marked. Our data suggest that TRPV1 may be involved in pain mechanisms associated with cervical ripening and labor. Furthermore, these data support the concept that cervix uteri may be the major site from which labor pain emanates. Our findings also support the possibility of developing alternative approaches to treat labor pain.

Treatment of idiopathic intracranial hypotension: cervicothoracic and lumbar blood patch and peroral steroid treatment.

METHODS: Twelve consecutive patients with clinical symptoms and testing results compatible with a diagnosis of idiopathic intracranial hypotension (IIH), but no identifiable site of cerebrospinal fluid (CSF) leakage, were treated with a cervicothoracic or lumbar epidural "blood patch" (EBP) or orally administered steroids. RESULTS: Prompt and complete relief from headache persisting for at least 4 months was attained in 3 of 4 treatments with cervicothoracic EBP, 2 of 15 with lumbar EBP, and 4 of 8 with steroids. CONCLUSION: These results suggest that in patients who presumably suffer from IIH and yet have no identifiable site of CSF leakage, the presumed leakage more often occurs at the cervicothoracic level than the lumbar. In addition, our experience suggests that some IIH patients may be treated effectively with oral steroids and a trial of such therapy may be considered as an alternative to EBP.

Obstetric pain relief and its association with remembrance of labor pain at two months and one year after birth.

The association between obstetric pain relief and long-term memory of pain is poorly researched in spite of the fact that a woman's memory of childbirth may affect her emotional wellbeing and future reproduction. The aim of this study was to investigate the association between epidural analgesia and other forms of pain relief, and memory of pain at two months and one year after birth. A national sample of 2482 Swedish speaking women with vaginal delivery or emergency cesarean section preceded by labor were followed from early pregnancy to one year after birth. Data were collected by three postal questionnaires: in early pregnancy, and two months and one year after the birth. Recollection of intense pain at two months and one year was associated with high rates of pain relief, and this was most obvious regarding epidural analgesia in first-time mothers. When comparing women with the same pain score at two months postpartum who had and who did not have an epidural, the first group seemed to have greater difficulty forgetting pain 10 months later. Possible explanations of these findings are discussed.

Severe neurological complications after central neuraxial blockades in Sweden 1990-1999.

BACKGROUND: Central neuraxial blockades find widespread applications. Severe complications are believed to be extremely rare, but the incidence is probably underestimated. METHODS: A retrospective study of severe neurologic complications after central neuraxial blockades in Sweden 1990-1999 was performed. Information was obtained from a postal survey and administrative files in the health care system. During the study period approximately 1,260,000 spinal blockades and 450,000 epidural blockades were administered, including 200,000 epidural blockades for pain relief in labor. RESULTS: : The 127 complications found included spinal hematoma (33), cauda equina syndrome (32), meningitis (29), epidural abscess (13), and miscellaneous (20). Permanent neurologic damage was observed in 85 patients. Incidence of complications after spinal blockade was within 1:20-30,000 in all patient groups. Incidence after obstetric epidural blockade was 1:25,000; in the remaining patients it was 1:3600 (P < 0.0001). Spinal hematoma after obstetric epidural blockade carried the incidence 1:200,000, significantly lower than the incidence 1:3,600 females subject to knee arthroplasty (P < 0.0001). CONCLUSIONS: : More complications than expected were found, probably as a result of the comprehensive study design. Half of the complications were retrieved exclusively from administrative files. Complications occur significantly more often after epidural blockade than after spinal blockade, and the complications are different. Obstetric patients carry significantly lower incidence of complications. Osteoporosis is proposed as a previously neglected risk factor. Close surveillance after central neuraxial blockade is mandatory for safe practice.