Thrombocytopenia and platelet functional defects in pre-eclampsia: implications for regional anaesthesia

Evaluating hemostatic thresholds for neuraxial anesthesia in adults with hemorrhagic disorders and tendencies: A scoping review

Neuraxial anesthesia can be complicated by spinal or epidural hematoma and may result in permanent neurologic injury. There is a paucity of literature characterizing this serious complication in patients with congenital and acquired hemorrhagic disorders or tendencies. The objective of this scoping review was to describe the hemostatic laboratory parameters where neuraxial anesthesia has been administered with and without spinal and epidural hematoma in patients with preexisting hemorrhagic disorders and tendencies, including immune thrombocytopenia, gestational thrombocytopenia, thrombocytopenia associated with hypertensive disorders of pregnancy, platelet function disorders, von Willebrand disease, coagulation factor deficiencies, and fibrinogen disorders. A systematic search of Ovid MEDLINE, CINAHL, Embase, Scopus, and Web of Science was performed. Two authors independently reviewed all titles, abstracts, and full texts to determine study eligibility and extract data. Qualitative synthesis of 91 studies revealed significant gaps in our understanding of the risk of spinal and epidural hematoma in patients with hemorrhagic disorders and tendencies, including few studies of males and in nonobstetric settings. Most reviewed articles were small, retrospective studies at high risk for potential bias. With such low-quality data, we were unable to provide any true estimates of the risk of spinal or epidural hematoma for these patients, nor could we attribute any specific hemostatic or laboratory values to increased risk of hematoma. There is a need both for larger and more rigorously designed and reported studies on this subject and for structured, comprehensive recommendations for safe administration and removal of neuraxial anesthesia in patients with hemorrhagic disorders and tendencies.

[SBA 2020: Regional anesthesia guideline for using anticoagulants update]

The development of protocols to prevent perioperative Venous Thromboembolism (VTE) and the introduction of increasingly potent antithrombotic drugs have resulted in concerns of increased risk of neuraxial bleeding. Since the Brazilian Society of Anesthesiology (SBA) 2014 guideline, new oral anticoagulant drugs were approved by international regulating agencies, and by ANVISA. Societies and organizations that try to approach concerns through guidelines have presented conflicting perioperative management recommendations. As a response to these issues and to the need for a more rational approach, managements were updated in the present narrative revision, and guideline statements made. They were projected to encourage safe and quality patient care, but cannot assure specific results. Like any clinical guide recommendation, they are subject to review as knowledge grows, on specific complications, for example. The objective was to assess safety aspects of regional analgesia and anesthesia in patients using antithrombotic drugs, such as: possible technique-associated complications; spinal hematoma-associated risk factors, prevention strategies, diagnosis and treatment; safe interval for discontinuing and reinitiating medication after regional blockade.

Platelet function in preeclampsia - a systematic review and meta-analysis

Preeclampsia is a serious pregnancy-related complication. Platelets are potentially important in the pathogenesis of preeclampsia, and platelet function analyses may prove as sensitive preeclampsia biomarkers. This study aimed to systematically review and summarise the literature on platelet function markers in preeclampsia. This systematic review was conducted according to PRISMA and registered in PROSPERO. Relevant studies were identified through PubMed and Embase on 15/08/17. As platelet function markers platelet activation, platelet aggregation and platelet adhesion markers were included. If possible, relevant data were extracted for each marker to perform a meta-analysis of the mean difference between women with and without preeclampsia. All 69 included articles underwent quality rating. Some platelet activation markers, especially p-selectin and mean platelet volume (MPV), were significantly increased comparing the two groups of women, while others were not. The meta-analysis demonstrated that, overall, women with preeclampsia had significantly higher MPV than in women without preeclampsia. No significant difference was found regarding platelet aggreg`ation comparing the two groups. Platelet adhesion was investigated in noneof the included studies. In conclusion, further studies are warranted to investigate platelet activation markers future role as predictive markers in preeclampsia. MPV is suggested as the most promising biomarker for evaluating platelet function in preeclampsia.

Managing anticoagulated patients during neuraxial anaesthesia

The widespread use of central neuraxial block (CNB) and the prevalence of anticoagulation for different indications have led to an inevitable overlap between the two. The most serious complication of CNB in anticoagulated patients is the risk of spinal/epidural haematoma. Performing CNB in these patients is a complex decision that should take into account the twin risks of bleeding and venous/arterial thrombosis if anticoagulation therapies were to be stopped. Various guidelines have been issued to achieve normal haemostasis and thus allow safe administration of CNB. However, the evidence base for many such recommendations is weak, relying mainly on case reports, small studies and pharmacokinetics of the drugs. Given these limitations it is crucial to fully assess individual risk factors and understand anticoagulant pharmacokinetics in order to appropriately set time intervals for catheter insertion/removal. This paper will review traditional and newer anticoagulation/antiplatelet therapies with a view to improving the management of anticoagulated patients undergoing CNB.

Pre-eclampsia: fluids, drugs, and anesthetic management

Severe pre-eclampsia is a complex disease, which taxes the expertise of even the most experienced obstetric anesthesiologist. The treatment should focus on stabilization of blood pressure, optimization of fluid status, and prevention of convulsions. Neuraxial blocks for labor and delivery offer many benefits to the mother and her infant. For cesarean section, there is unequivocal evidence of superiority of neuraxial anesthesia over general anesthesia. If general anesthesia is needed, careful preanesthetic preparation and meticulous airway management is essential. The successful and safe peripartum management of the pre-eclamptic patient and her infant is a team effort among the anesthesiologist, obstetrician, and neonatologist.

Central nerve block and coagulation: a survey of obstetric anaesthetists

We conducted a survey amongst anaesthetists in 264 obstetric units in the UK to examine their practice in relation to potential clotting abnormalities. The survey was conducted between July and November 1998 and shows a varied opinion and practice. We received a return of 226 (86%) with 64-78% of respondents willing to perform a central nerve block at a platelet count of 80 x 10(9)/L or more. Patients on aspirin alone or aspirin and heparin would be given a central nerve block by up to 96% and 43% of respondents respectively. Following administration of heparin, up to 22% of respondents would perform a central nerve block within 2 h while up to 64% would wait beyond 4 h. Eighty-five units had departmental policies on the removal of epidural catheters but only 15 differentiated between unfractionated and low molecular weight heparin.

HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome: the benefit of corticosteroids

OBJECTIVE

The purpose of this study was to determine the effect of corticosteroids on platelet counts and liver functions in women with pregnancies complicated by the HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome.

STUDY DESIGN

The study group consisted of 93 patients between 24 and 34 weeks' gestation diagnosed with HELLP syndrome. All were given intramuscular injections of either betamethasone or dexamethasone. The 3 most common regimens used were 12 mg of intramuscular betamethasone administered twice 12 hours apart, 12 mg of intramuscular betamethasone administered twice 24 hours apart, and 6 mg of intramuscular dexamethasone administered 4 times 6 hours apart. Precorticosteroid and postcorticosteroid platelet counts and liver function test results were compared. The differences in improvement in hematologic abnormalities among the 3 corticosteroid regimens were also analyzed.

RESULTS

The hematologic abnormalities seen in the 93 patients with HELLP syndrome improved after the administration of corticosteroids. The platelet count increased by 23.3 x 10(3)/microL (P <.001). A statistically significant decrease was seen in liver enzyme levels. The alanine aminotransferase decreased by 31.6 IU/L, the aspartate aminotransferase decreased by 52.1 IU/L, and the alkaline phosphatase decreased by 7.6 IU/L. Of the 3 regimens used, 2 doses of 12 mg of intramuscular betamethasone given every 12 hours improved the liver function to the greatest degree.

CONCLUSIONS

This study demonstrates that corticosteroids produce a significant improvement in the hematologic abnormalities associated with HELLP syndrome. Two doses of betamethasone given 12 hours apart was the most effective corticosteroid regimen.

Effects of magnesium sulfate infusion upon clotting parameters in patients with pre-eclampsia

The objectives of this study were to evaluate the possible mechanisms involved in prolongation of bleeding time in pre-eclamptic patients receiving a magnesium sulfate infusion to prevent convulsions. Eighteen pre-eclamptic patients near term or at term (4 cases 33 to 35 weeks; the remainder > 36 weeks) were studied. Fifteen of them received magnesium sulfate infusion; 3 did not and served as controls. Bleeding time (modified Ivy method with Surgicutt), platelet count, platelet aggregation pattern, as well as serum arachidonic acid metabolites [thromboxane B2 (TxB2) and 6-Keto-prostaglandin F1 alpha (6-Keto-PGF1 alpha)] werde done on admission to the labor floor (before magnesium infusion) and repeated at discontinuation of the infusion, 12-24 hours postpartum; the controls received the second test 24 hours postpartum. Thirteen of 15 patients receiving magnesium sulfate had an increase in bleeding time from an average of 6 minutes 31 seconds to 11 minutes 56 seconds, an 82% rise (p < 0.004). In 2 there was a decrease. Among the 3 controls the averages were 6 minutes 38 seconds and 6 minutes 3 seconds. The total magnesium given ranged from 52.5 to 145 grams. Platelet counts averaged 251,000/mm3 (range 145,000-519,000). Platelet aggregation pattern done in 11 patients and was normal and unchanged after magnesium in 10 of the patients with increased bleeding time and one control. TxB2 and 6-Keto-PGF1 alpha levels did not change significantly either after magnesium administration (688 and 135 pgm/ml, to 654 and 117) or in controls (695 and 230 pgm/ml, to 445 and 225). Likewise, the ratio of these 2 substances did not change in either group (6.3 to 6.6, and 4.2 to 2.2). There was no correlation between duration of infusion or total magnesium given and directions of small changes observed. This study confirms a prior preliminary observation that magnesium sulfate infusion, as currently used to prevent eclamptic convulsions, induces a significant prolongation of bleeding time. This effect is mediated neither by changes in platelets count or aggregation pattern, nor by changing the level or ratios of serum arachidonic acid metabolites (TxB2 and 6-Keto-PGF1 alpha). Further studies are needed to clarify the mechanism of this clinically important observation of increased bleeding following magnesium sulfate infusion.

Fiberoptic intubation using intraoral glossopharyngeal nerve block in a patient with severe preeclampsia and HELLP syndrome

Rationale and technique for use of intraoral glossopharyngeal nerve block is described in a parturient with severe preeclampsia and a past history of difficult intubation. Indications and contraindications for administration of other forms of airway anesthesia are discussed.

The intensive care management of severe pregnancy induced hypertension

Severe pregnancy induced hypertension (PIH, pre eclampsia) is a disease which is now treated in the intensive care unit rather than with sedation in a dark room. The pathophysiology is now well understood and allows for better and more effective management. This paper looks at the strict haemodynamic monitoring and management required to prevent complications such as eclampsia, DIC, HELLP syndrome, maternal and foetal death. The nurse's role in the management of severe PIH is discussed.