Four years' experience of a ROTEM® -guided algorithm for treatment of coagulopathy in obstetric haemorrhage.

We report four years of observational data from a large UK hospital and tertiary referral unit, following the introduction of a rotational thromboelastometry-guided algorithm for treatment of coagulopathy in major obstetric haemorrhage. Fibrinogen concentrate was used to treat acquired hypofibrinogenaemia as defined by a FibTEM A5 value of < 7 mm, or 7-12 mm with ongoing or high risk of haemorrhage. Of 32,647 deliveries over 4 years, 893 (2.7%) women had an estimated blood loss ≥ 1500 ml. Two-hundred and three (23%) of these had a FibTEM A5 ≤ 12 mm and 110 received fibrinogen concentrate. We compared clinical outcomes and blood product use with 52 patients who met the same criteria, over a 12-month pre-intervention period during which shock packs were used. In the algorithm group, there was a significant reduction in the number of units (p < 0.0001) and total volume (p = 0.0007) of blood products transfused, with a reduction in transfusion-associated circulatory overload (p = 0.002). Women with placental abruption exhibited more severe coagulopathy and required higher doses of fibrinogen concentrate than women who bled due to other causes. Analysis of rotational thromboelastometry results demonstrated that coagulopathy is not observed in all women who suffer obstetric haemorrhage and cannot be predicted solely by blood loss. Therefore, formulaic treatment with blood products is not justified. When coagulopathy does occur, it appears to be multifactorial and can be severe. Point-of-care testing allows early identification and individualised treatment of coagulopathy. This is supported by the improved outcomes reported.

Accuracy and precision of the ultrasound cardiac output monitor (USCOM 1A) in pregnancy: comparison with three-dimensional transthoracic echocardiography.

BACKGROUND: Cardiac output (CO) monitoring is helpful in the assessment of critically ill pregnant women, but invasive monitors are often unsuitable for use. We aimed to measure agreement between the non-invasive ultrasound cardiac output monitor (USCOM) and three-dimensional transthoracic echocardiography (3D-TTE) in pregnant women. METHODS: Healthy pregnant women from 25 weeks gestation onwards participated. In the left lateral position at rest, CO was measured with the USCOM and 3D-TTE. A single operator performed all USCOM measurements, with a different operator performing all echocardiography. Both were blinded to results from the other device. Each USCOM trace was analysed using two modes: flowtrace (FT) and touchpoint (TP). A second, blinded USCOM reading was taken to assess reproducibility. RESULTS: USCOM readings were obtained in 92, and 3D-TTE images in 85 participants. The mean CO was 5.7, 7.7, and 6.2 litre min(-1) measured by 3D-TTE, USCOM FT, and USCOM TP, respectively. USCOM bias was +2.0 litre min(-1) (FT) and +0.4 litre min(-1) (TP). Limits of agreement were -0.2 to +4.2 litre min(-1) (FT) and -1.4 to +2.3 litre min(-1) (TP). The mean percentage difference was 32.6% (FT) and 31.4% (TP) for CO and 27.0% (FT) and 27.5% (TP) for stroke volume. Intraclass correlation between repeated USCOM readings was 0.9 (FT) and 0.86 (TP). CONCLUSIONS: USCOM has acceptable agreement with 3D-TTE for the measurement of CO in pregnancy. The positive bias of the USCOM, particularly in the FT mode, may be due to the hyperdynamic cardiovascular state in pregnancy. We suggest using the TP mode in this patient population.

When does obstetric coagulopathy occur and how do I manage it?

Anticipating obstetric coagulopathy is important when obstetric anaesthetists are involved in the clinical management of women with postpartum haemorrhage. Although the incidence of coagulopathy in women with postpartum haemorrhage is low, significant hypofibrinogenaemia is associated with major haemorrhage-related morbidity and thus early identification and treatment is essential to improve outcomes. Point-of-care viscoelastic haemostatic assays, including thromboelastography and rotational thromboelastometry, provide granular information about alterations in clot formation and hypofibrinogenaemia, allow near-patient interpretation of coagulopathy, and can guide goal-directed treatment. If these assays are not available, anaesthetists should closely monitor the maternal coagulation profile with standard laboratory testing during the active phase of postpartum bleeding in order to rule coagulopathy 'in or out', decide if pro-haemostatic therapies are indicated, and assess the response to haemostatic support.

Up-regulation of LFA-1 allows liver-resident memory T cells to patrol and remain in the hepatic sinusoids.

Liver-resident CD8+ T cells are highly motile cells that patrol the vasculature and provide protection against liver pathogens. A key question is: how can these liver CD8+ T cells be simultaneously present in the circulation and tissue-resident? Because liver-resident T cells do not express CD103 - a key integrin for T cell residence in epithelial tissues - we investigated other candidate adhesion molecules. Using intra-vital imaging we found that CD8+ T cell patrolling in the hepatic sinusoids is dependent upon LFA-1-ICAM-1 interactions. Interestingly, liver-resident CD8+ T cells up-regulate LFA-1 compared to effector-memory cells, presumably to facilitate this behavior. Finally, we found that LFA-1 deficient CD8+ T cells failed to form substantial liver-resident memory populations following Plasmodium or LCMV immunization. Collectively, our results demonstrate that it is adhesion through LFA-1 that allows liver-resident memory CD8+ T cells to patrol and remain in the hepatic sinusoids.

Coagulopathy and placental abruption: changing management with ROTEM-guided fibrinogen concentrate therapy.

Placental abruption may cause significant haemorrhage and coagulopathy that can progress rapidly due to simultaneous consumption and depletion of clotting factors. Plasma fibrinogen levels are predictive of further haemorrhage. Rapid detection and treatment of hypofibrinogenaemia is essential in the evolving clinical and haematological situation. The use of near-patient testing of coagulation using rotational thromboelastometry (ROTEM) allows dynamic monitoring of coagulopathy. Following the introduction of fibrinogen concentrate into our unit, a ROTEM-guided algorithm was developed for use in obstetric haemorrhage. We describe four cases of placental abruption, haemorrhage and severe coagulopathy that span the introduction of the algorithm. Three cases were associated with intrauterine death and the fourth with delivery of an extremely premature neonate. Rotational thromboelastometry was used in all cases but methods of fibrinogen replacement differ, illustrating evolving management of the condition in our unit.

Racial differences in nitrogen content of nails among adolescents.

Ectodermal derivatives provide a readily accessible means of chemically evaluating body protein composition. Therefore, it has been postulated that the analysis of nail nitrogen content may reflect recent nutritional status. Assessment of nail nitrogen content has been previously reported in a small group of neonates and school children. The present study was undertaken to determine if standards for nail nitrogen content could be established for adolescents which could then be used in the assessment of protein nutritional status. Nail clippings were obtained from 118 economically indigent urban black youth, 10 black and 39 white subjects from wealthy suburban communities in the New York area, and 10 poor white-Indian adolescents residing within a barrio in Lima, Peru. Nail samples were analyzed for protein content using the micro Kjeldahl technique. Mean nail nitrogen content for wealthy suburban and impoverished urban black youth was 136 and 137 mg N/g of nail, respectively. Values for poor Peruvian white-Indian and affluent suburban white adolescents were 142 and 141 mg N/g of nail, respectively. The differences between ethnic groups were significant using t test analysis at a P value of less than 0.001. No differences, however, were found between either wealthy and poor of the same racial background or when the data were analyzed by gender. These results suggest that differences in nail nitrogen content are at least in part a reflection of ethnicity. These racial differences must be considered in assessing nutritional status by nail nitrogen analysis.

Serum gamma-glutamyl transpeptidase acitvity: a chemical determinant of alcohol consumption during adolescence.

The drinking habits of 55 adolescents, aged 12 to 22 years, were evaluated in light of the current presumed upsurge in adolescent alcohol use. SGPT, SGOT, and alkaline phosphatase concentrations were essentially normal in all subjects. Serum gamma-glutamyl transpeptidase (GGTP) concentrations were elevated in 12 of 15 adolescents who consumed six or more drinks per day. It is suggested that this test may warrant inclusion among other targeted screening procedures performed in teenage patients suspected of heavy alcohol consumption.

Mesenteric ischemia: a cause of increased gastric blood flow, hyperacidity, and acute gastric ulceration.

1. The effects of acute diminution in superior mesenteric arterial flow on gastric blood flow and acidity were studied in 17 anesthetized dogs. 2. Acute mesenteric ischemia produced a rise in celiac and gastric blood flow, higher total acid concentrations, and increased total acid secretion. Ischemia of 12 hours' duration was associated with gross gastric bleeding and in one animal acute superficial gastric ulcerations. 3. The rise in celiac and gastric blood flow appeared to be a hemodynamic response to the fall in mesenteric arterial pressure and was minimized by ligation of the major artery connecting the mesenteric and celiac vascular beds. 4. The increased acid concentration and secretion appeared to be directly related to, and a result of, the augmented gastric blood flow. 5. A direct causal relationship between mesenteric vascular occlusions and subsequent upper gastrointestinal bleeding is suggested.

Continuous intrapartum pH, pO2, pCO2, and SpO2 monitoring.

The goal of intrapartum surveillance and its further development is better patient care for both the fetus and the gravida. A normal FHR pattern is usually associated with the delivery of a normal well-oxygenated infant; however, a nonreassuring FHR is not always associated with the delivery of a compromised infant. This situation has led to an increase in unnecessary obstetric interventions in the form of a rising cesarean section rate. Fetal scalp sampling was developed in an attempt to improve the predictive value of electronic FHR monitoring, but because this technique is not widely used, management decisions are frequently made using FHR patterns alone. Much research has been performed in the search for a continuous biochemical measurement of fetal status, including continuous pH, pO2, or pCO2 and various combinations of these methodologies. None of these measurements are used in current clinical practice, mainly owing to technical problems and difficulties associated with the continuous direct measurement of these parameters in fetal blood throughout labor. The promising new field of fetal pulse oximetry has the potential to provide reliable, meaningful, and reproducible data as shown in early cross-sectional studies and more recent longitudinal studies. By identifying developing hypoxia, this technology may reduce the uncertainty associated with electronic FHR monitoring. Fetal pulse oximetry may also provide critical information relating to the detection and management of the hypoxic fetus. Any new method of intrapartum fetal monitoring requires careful evaluation to assess its potential value before its introduction into clinical practice. The use of fetal SpO2 monitoring in the presence of a nonreassuring FHR pattern is being examined in a multicenter randomized controlled trial. This study will address the question of whether supplementary monitoring of fetal SpO2 levels can lead to a reduction in the cesarean section rate for fetal distress. The available data on fetal noninvasive pulse oximetry have been obtained from a combination of well-designed cohort studies (level II-2 evidence) or from earlier multiple time series (level II-3 evidence). The results from the US Multicenter Trial (level I evidence) should provide a significant addition to current evidence. A continuous fetal noninvasive monitor measuring fetal oxygenation directly could lead to an improvement in the sensitivity and specificity of fetal surveillance. This improvement could ultimately result in a reduction in unnecessary interventions by differentiating hypoxic fetuses from nonhypoxic fetuses and, more importantly, may lead to earlier intervention for fetuses in danger of serious compromise.

Comparing fetal pulse oximetry with scalp pH.

OBJECTIVE: To determine whether pulse oximetry has the potential to replace scalp blood pH sampling in infants with abnormal cardiotocographs. STUDY DESIGN: The average scalp oximetry reading in labor recorded with an experimental N400 system was compared with fetal scalp blood pH. RESULTS: The average oximetry readings were unrelated to the pH of aerobically sampled fetal scalp blood. There was no subgroup of acidemic infants with a low oximetry reading. CONCLUSION: Pulse oximetry readings with present technology do not reflect scalp pH. The equipment is improving, but at this time pulse oximetry is not a simple alternative for scalp capillary blood sampling.

The effect of uterine contractions on fetal oxygen saturation.

OBJECTIVE: To find out what happens to fetal arteriolar oxygen saturation during a uterine contraction. DESIGN: Prospective observational study. SETTING: Labour ward, St James's University Hospital, Leeds. SUBJECTS: Eighteen women in normal labour monitored with a fetal scalp surface pulse oximetry sensor, an intrauterine pressure catheter, and a head to cervix force transducer. METHODS: The effect of intrauterine pressure and head to cervix force on fetal arteriolar oxygen saturation was examined using time series analysis and a regression model of 159 contractions. OUTCOME MEASURE: Fetal oxygen saturation during a contraction. RESULTS: The average oxygen saturation drops after a contraction. The greatest drop in oxygen saturation is reached 92 s after the peak of a contraction and takes approximately 1 min 30 s to recover (P = 0.036). CONCLUSION: Uterine contractions during normal labour affect fetal oxygen saturation.

The effect on fetal arteriolar oxygen saturation resulting from giving oxygen to the mother measured by pulse oximetry.

OBJECTIVE: To determine if pulse oximetry could detect any changes in fetal arteriolar oxygen saturation resulting from maternal administration of oxygen. DESIGN: A prospective study comparing study comparing the fetal pulse oximetry reading before and after giving 27% and 100% oxygen to the mother. The data were collected using an experimental pulse oximeter and a sensor specifically adapted to cope with the problems of fetal pulse oximetry. SETTING: Labour ward, St. Jame's University Hospital, Leeds University, UK. SUBJECTS: Twelve fetuses presenting by the vertex in normal uncomplicated labour. MAIN OUTCOME MEASURES: The change in fetal arteriolar oxygen saturation recorded by the pulse oximeter in response to oxygen administration to the mother. RESULTS: Twenty-seven percent oxygen increased the average fetal arteriolar oxygen saturation by 7.5%, the effect being reversed when the oxygen was withdrawn. One hundred percent oxygen increased fetal arteriolar oxygen saturation by 11% and when the oxygen was withdrawn oxygen saturation dropped by 10%. One hundred percent inspired maternal oxygen was more effective than 27%. The gradient of the fetal oxygen regression slope is steeper with 100% oxygen than 27% and it is steeper when oxygen is given compared to when it is withdrawn. This suggests that the fetus responds to the new placental oxygen gradient by accepting oxygen more rapidly than it gives it up. Using a quadratic regression model, it took 9 min for fetal oxygen saturation to reach its maximum value after giving the mother oxygen. CONCLUSION: This study confirms that a pulse oximeter is able to measure an increase in fetal arteriolar oxygen saturation when oxygen is administered to the mother.