Disorders of coagulation in pregnancy.

The process of haemostasis is complex and is further complicated in the parturient because of the physiological changes of pregnancy. Understanding these changes and the impact that they have on the safety profile of the anaesthetic options for labour and delivery is crucial to any anaesthetist caring for the parturient. This article analyses current theories on coagulation and reviews the physiological changes to coagulation that occur during pregnancy and the best methods with which to evaluate coagulation. Finally, we examine some of the more common disorders of coagulation that occur during pregnancy, including von Willebrand disease, common factor deficiencies, platelet disorders, the parturient on anticoagulants, and the more rare acute fatty liver of pregnancy, with a focus on their implications for neuraxial anaesthesia.

The association between the introduction of quantitative assessment of postpartum blood loss and institutional changes in clinical practice: an observational study.

BACKGROUND: Imprecise visual estimates of blood loss contribute to morbidity from postpartum hemorrhage. We examined the impact of quantitative assessment of postpartum blood loss on clinical practice and outcomes. METHODS: An observational study comparing blood loss, management and outcomes between two historical cohorts (August 2016 to January 2017 and August 2017 to January 2018) at an academic tertiary care center. Patients in the intervention group (second period) had blood loss quantified compared with visual estimation for controls. RESULTS: We included 7618 deliveries (intervention group n=3807; control group n=3811). There was an increase in the incidence of hemorrhage (blood loss >1 L) in the intervention group for both vaginal (2.2% vs 0.5%, P <0.001) and cesarean delivery (12.6% vs 6.4%, P <0.001). There was also a difference in median blood loss for vaginal (258 mL [151-384] vs 300 mL [300-350], P <0.001); and for cesarean delivery (702 mL [501-857] vs 800 mL [800-900], P <0.001). The median red blood cell units transfused was different in the intervention group having cesarean delivery (2 units [1-2] vs 2 units [2-2], P=0.043). Secondary uterotonic usage was greater in the intervention group for vaginal (22% vs 17.3%, P <0.001) but not cesarean delivery (7.0% vs 6.0%, P=0.177). Laboratory costs were different, but not the re-admission rate or length of stay. CONCLUSIONS: Quantifying blood loss may result in increased vigilance for vaginal and cesarean delivery. We identified an association between quantifying blood loss and improved identification of postpartum hemorrhage, patient management steps and cost savings.

Systemic adjunct analgesics for cesarean delivery: a narrative review.

It is critical to adequately treat postoperative cesarean delivery pain. The use of parenteral or neuraxial opioids has been a mainstay, but opioids have side effects that can be troubling and the opioid crisis in the United States has highlighted the necessity to utilize analgesics other than opioids. Other analgesic options include neuraxial analgesics, nerve blocks such as the transversus abdominis plane block, and non-opioid parenteral and oral medications. The goal of this article is to review non-opioid systemic analgesic adjuncts following cesarean delivery, focusing on their efficacy and side effects as well as their impact on reduction of opioid requirements after surgery.

Delayed diagnosis of posterior reversible encephalopathy syndrome (PRES) in a parturient with preeclampsia after inadvertent dural puncture.

Posterior reversible encephalopathy syndrome is a rare complication generally associated with headache and acute changes in blood pressure. We present a case of posterior reversible encephalopathy syndrome where diagnosis was delayed because the patient also had preeclampsia and an inadvertent dural puncture, both associated with headache. The clinical challenge and the need for prompt diagnosis and treatment are emphasized.

Evaluation of the platelet function analyzer (PFA-100) vs. the thromboelastogram (TEG) in the parturient.

BACKGROUND: The platelet function analyzer (PFA-100) is a bedside test of coagulation designed to evaluate platelet function. It measures the time required for whole blood to occlude a membrane impregnated with either epinephrine (EPI) or adenosine 5'diphosphate (ADP). The results are reported as closure time (CT-EPI or CT-ADP) in seconds. The thromboelastogram (TEG) measures whole blood clotting and the maximum amplitude (MA) correlates with platelet count and function. We wished to establish whether there is a correlation between the CT and platelet count, between the CT and MA, and between the MA and platelet count. METHODS: Platelet count, CT, and MA were measured in blood drawn from 172 healthy term parturients using the PFA-100. RESULTS: We were unable to detect a significant correlation between the CT-EPI and platelet count (r=-0.1, P=0.21), or the CT-ADP and platelet count (r=-0.02, P=0.83). We also did not find a correlation between the CT-EPI and MA (r=-0.13, P=0.12) or between the CT-ADP and MA (r=-0.11, P=0.19). However, we found a significant correlation between platelet count and MA (r=0.33, P<0.001). CONCLUSIONS: We conclude that the CT does not correlate with the platelet count or MA in the parturient, but the TEG does. Therefore the TEG may be a better tool to evaluate coagulation in the parturient with thrombocytopenia.

Anesthesia for nonobstetric surgery during pregnancy.

Approximately 50,000 pregnant women undergo nonobstetric surgery each year in the United States. Administering anesthesia during such surgery is one of the only situations in which anesthesia impacts on more than one individual (mother and fetus) at the same time. Providing a safe anesthetic to the pregnant woman requires an understanding of the physiologic changes of pregnancy and the impact of anesthesia and surgery on the developing fetus. The following review will consider the risks of the mother and to the fetus during nonobstetric surgery.

Quality of analgesia when air versus saline is used for identification of the epidural space in the parturient.

BACKGROUND AND OBJECTIVES: Identification of the epidural space is often performed using the loss-of-resistance technique (LOR), commonly with air or saline. The effect of air or saline on the quality of labor epidural analgesia has not been adequately studied. METHODS: Women who requested labor epidural analgesia were randomly assigned to 1 of 2 groups depending on the syringe contents used for the LOR technique and injected into the epidural space. In the air group (n = 80) the anesthesiologist used 2 mL of air, and in the saline group (n = 80) the anesthesiologist used 2 mL of 0.9% saline. After LOR was obtained, a multiorifice epidural catheter was threaded 5 cm into the epidural space and 13 mL of bupivacaine 0.25% was administered in divided doses. The success of the epidural block was determined by asking the patient if she required additional medication 15 minutes later. The occurrence of paresthesias and intravascular or subarachnoid catheters was noted. RESULTS: In the air group, 36% of patients requested additional pain medication, and in the saline group 19% requested additional medication (P =.022). We were not able to find a statistically significant difference between groups in the incidence of paresthesias (42% air v 51% saline), intravascular catheters (5% air v 8% saline), or subarachnoid catheters (0 in both groups). CONCLUSIONS: Using 0.9% saline for the LOR technique is associated with better analgesia as compared with air for labor analgesia, and this advantage should be considered when selecting the syringe contents for the LOR technique.

Anesthesia for an achondroplastic dwarf presenting for urgent cesarean section.

Achondroplasia is a physeal dysplasia which leads to dwarfism secondary to a decrease in the proliferation of cartilage in the growth plate. This, coupled with normal persistent bone formation, leads to the development of short tubular bones. Achondroplastic dwarfism is among the more common types of dwarfism and is inherited as an autosomal dominant trait. Its incidence is reported as 1 in 26,000 live births. Most achondroplastic dwarfs have a normal life span. The selection and management of anesthesia for the achondroplastic dwarf must take into account a variety of anatomic deformities. The physiologic and hormonal changes of pregnancy further complicate anesthetic administration. We report the safe use of a continuous lumbar epidural anesthetic in an achondroplastic dwarf who presented for urgent cesarean section.

Cardiovascular consequences of the concomitant administration of nifedipine and magnesium sulfate in pigs.

There is concern regarding the interaction of magnesium sulfate and nifedipine used concomitantly in obstetrical patients, because both are calcium channel antagonists and may induce myocardial depression as well as peripheral vasodilatation. The objective of this study was to determine the hemodynamic consequences of concomitant administration of nifedipine and magnesium sulfate in anesthetized pigs. Twelve pigs were anesthetized with sodium pentobarbital, intubated mechanically ventilated. Following placement of invasive monitors, baseline hemodynamic measurements were made. Animals were randomized to one of two groups. Group I received nifedipine first, and then magnesium sulfate. Group II received magnesium sulfate first, and then nifedipine. Hemodynamic measurements were recorded. Hypotension was treated with calcium chloride, ephedrine and phenylephrine. Nifedipine alone (Group I) decreased peripheral vascular resistance and mean arterial pressure (MAP) (P<0.05). Magnesium sulfate alone in group II decreased the first derivative of left ventricular pressure (LVdP/dt) and increased left ventricular end-diastolic pressure (LVEDP) (P<0.05). Magnesium sulfate also decreased peripheral vascular resistance and MAP The concomitant administration of nifedipine and magnesium sulfate in both groups I and 11 led to a further decrease in myocardial contractility, as evidenced by a decrease in LVdP/dt and increase in LVEDP (P<0.05). Treatment with calcium chloride or ephedrine was only partially successful in improving myocardial contractility. Phenylephrine increased peripheral vascular resistance and MAP, but did not improve myocardial function. In conclusion, the depressive effects of nifedipine and magnesium sulfate on the cardiovascular system are potentiated when administered concomitantly.

Information and concerns about obstetric anesthesia: a survey of 320 obstetric patients.

This study was undertaken to assess women's knowledge and concerns about obstetric anesthesia and to determine if they perceive a need for an anesthesia interview before the onset of labor. A 17 item questionnaire was distributed to 407 women on postpartum day one. The women were questioned about their knowledge, anxiety and concerns regarding obstetric anesthesia. The questionnaire was completed by 320 women, 57% of whom were Caucasian and 28% of whom had some postgraduate education. Most of the women (74%) had either a regional or general anesthetic for their delivery and 86% of the women admitted to having some anxiety about anesthesia. Although 82% of the women attempted to obtain information about anesthesia before labor, 28% did not feel adequately informed. The majority (59%) of the women would have wanted a preoperative visit with an anesthesiologist before labor. These results illustrate that most women are anxious about obstetric anesthesia and do not feel adequately prepared. Efforts at educating women about obstetric anesthesia would be welcomed by them and methods to accomplish this goal are discussed.

An ex utero intrapartum treatment procedure in a patient with a family history of malignant hyperthermia.

In the EXIT (ex utero intrapartum treatment) procedure, after uterine incision, uterine relaxation is maintained to prevent placental separation and the fetus is supported via the placenta until the airway is successfully established. The traditional method to maintain uterine relaxation is with the use of high-dose potent inhaled anesthetics during general anesthesia. A patient with a family history of malignant hyperthermia required an EXIT procedure. The history of malignant hyperthermia precluded the use of potent inhaled anesthetics and an alternate plan using propofol and remifentanil infusions for anesthesia and nitroglycerin 16 µg/kg/min for uterine relaxation allowed for good surgical conditions. The presence of malignant hyperthermia required an alternate plan and close collaboration in order to ensure good patient outcome.

A survey of anesthesiologists' and nurses' attitudes toward the implementation of an Anesthesia Information Management System on a labor and delivery floor.

BACKGROUND: An anesthesia information management system (AIMS) is most frequently used in the operating room, but not on labor and delivery (L&D). The purpose of this study is to describe the implementation of an AIMS on L&D and the attitudes of practitioners (anesthesiologists and nurses) toward the system. METHODS: The anesthesiology survey focused on satisfaction with the L&D AIMS, comparison of the L&D AIMS with a handwritten anesthesia record, and comparison of the L&D AIMS with the operating room AIMS. The nursing survey focused on nursing satisfaction with the L&D AIMS and comparison of the L&D AIMS with a handwritten anesthesia record. RESULTS: Most anesthesiologists (76%) were satisfied with the L&D AIMS and 73% would not want to revert back to the paper record. However, most anesthesiologists felt the operating room AIMS was either superior or equal to the L&D AIMS. Although few nurses (4%) preferred the anesthesiologists revert back to the handwritten record overall, the nurses were neutral in their assessment of the AIMS. Most of the criticism related to the location of the system; 56% believed it was not in a convenient location and 74% thought the AIMS equipment "got in their way". CONCLUSIONS: Overall, the anesthesiologists and nurses are satisfied with the L&D AIMS and would not want to switch back to a handwritten record. We conclude that AIMS should not be limited to the operating room setting and can successfully be used in L&D.

Successful epidural anaesthesia for a patient with Takayasu's arteritis presenting for caesarean section.

The management of a 24-yr-old parturient with Takayasu's arteritis (TA) presenting at term for Caesarean section is discussed. The best anaesthetic management for the patient with TA is controversial, but avoiding regional anaesthesia has been suggested by some authors because of the risk of hypotension and the subsequent need for vasopressors. We report the use of regional anaesthesia in a term parturient with severe TA undergoing Caesarean section. Anaesthesia was provided with chloroprocaine 3%, via a lumbar epidural catheter. The initial doses of 60 mg and 150 mg were followed by a decrease in BP (from 110/70 to 70/40) which was corrected with iv fluids and ephedrine 25 mg. Additional doses of chloroprocaine, 150 and 90 mg, were uneventful. It is concluded that an epidural can be made in safety to provide anaesthesia for Caesarean section in patients with TA.

Safe epidural analgesia in thirty parturients with platelet counts between 69,000 and 98,000 mm(-3).

Regional anesthesia is a popular form of pain relief for the management of labor and delivery. Thrombocytopenia is considered a relative contraindication to the administration of regional anesthesia. Some authorities have recommended that an epidural anesthetic be withheld if the platelet count is <100,000 mm(-3). For the period of March 1993 through February 1996, we reviewed the charts of all parturients who had a platelet count <100,000 mm(-3) during the peripartum period. Eighty women met this criterion. Of these 80, 30 had an epidural anesthetic placed when the platelet count was <100,000 mm(-3) (range 69,000-98,000 mm(-3)), 22 had an epidural anesthetic placed with a platelet count >100,000 mm(-3) that subsequently decreased below 100,000 mm(-3), and 28 did not receive a regional anesthetic. We found no documentation of any neurologic complications in the medical records. We conclude that regional anesthesia should not necessarily be withheld when the platelet count is <100,000 mm(-3).

Pulmonary artery catheters and outcome in the perioperative period.

OBJECTIVE: To review the literature addressing use of the pulmonary artery catheter (PAC) in the perioperative patient. DATA SOURCE: All pertinent English language articles dealing with the use of pulmonary artery catheterization in perioperative patients were retrieved from 1977 through 1996. STUDY SELECTION: Articles were chosen if the perioperative use of pulmonary artery catheterization was studied or reviewed. DATA EXTRACTION: From the articles selected, information was obtained about changes in therapy and changes in outcome associated with PAC use in patients undergoing cardiac surgery, aortic surgery, peripheral vascular surgery, and neurosurgery. Information was also extracted about perioperative PAC use in geriatric patients and in patients with preeclampsia. DATA SYNTHESIS: Low-risk patients undergoing cardiac surgery do not appear to benefit from PAC use. Studies looking at high-risk patients undergoing cardiac surgery are lacking, making accurate determination of patient benefit difficult. The PAC may be useful in the management of some patients undergoing aortic surgery, though recent studies have identified populations of patients that can be safely monitored by less invasive means. Use of the PAC may lead to fewer complications in high-risk patients undergoing peripheral vascular surgery. Until data are forthcoming, it is not possible to accurately assess the overall impact of PAC use on complications and mortality in patients undergoing neurosurgical procedures. However, use of the PAC to monitor and treat air embolism in this group of patients does not appear to be appropriate. Routine perioperative use of the PAC does not appear to be appropriate because of age alone. Available scientific data do not support use of the PAC in patients with uncomplicated preeclampsia; however, some experts feel that PAC use may be helpful in the management of selected patients with severe preeclampsia. CONCLUSION: There are no Grade A indications for PAC use in the perioperative period. Current available literature suffers from a lack of randomized controlled clinical trials. Multicentered randomized controlled trials are needed.

The optimal distance that a multiorifice epidural catheter should be threaded into the epidural space.

Complications can occur during epidural placement for women in labor. As many as 23% of epidural anesthetics may not provide satisfactory analgesia. The cause of this may be technical. This study was undertaken to determine the optimal distance that a multiorifice catheter should be threaded into the epidural space to maximize analgesia and minimize complications. One hundred women in labor were enrolled in this prospective, randomized, and double-blind study. Patients were randomly assigned to have the epidural catheter threaded 3, 5, or 7 cm into the epidural space. After placement of the catheter and administration of a test dose with 3 mL of 0.25% bupivacaine, an additional 10 mL of 0.25% bupivacaine was administered in two divided doses. Fifteen minutes later, the adequacy of the analgesia was assessed by a blinded observer. We found that catheter insertion to a depth of 7 cm was associated with the highest rate of insertion complications while insertion to a depth of 5 cm was associated with the highest incidence of satisfactory analgesia. For women in labor who require continuous lumbar epidural anesthesia, we recommend threading a multiorifice epidural catheter 5 cm into the epidural space.

Epidural ropivacaine for the initiation of labor epidural analgesia: a dose finding study.

UNLABELLED: The purpose of our study was to determine the lowest concentration of ropivacaine that offers pain relief for the initiation of labor epidural analgesia. Women in active labor were enrolled in this prospective, randomized, double-blinded study to receive either ropivacaine 0.20% (Group I), ropivacaine 0.15% (Group II), or ropivacaine 0.10% (Group III). After placement of the epidural catheter, 13 mL of the study medication was administered. Fifteen minutes later, the adequacy of analgesia was assessed. If the woman reported that her degree of analgesia was not adequate, an additional 5 mL of the study medication was given, the degree of pain relief was reassessed 15 min later, and the study was concluded. A sequential study design was used to assess the success rates. We found that 26 of 28 (93%) women in Group I had adequate analgesia, compared with only 18 of 28 (64%) in Group II (P = 0.014) and 4 of 12 (33%) in Group III (P = 0.003). We conclude that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%. IMPLICATIONS: The lowest effective concentration of ropivacaine for the initiation of labor epidural analgesia has not been determined. We found that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%.

Practice patterns of anesthesiologists regarding situations in obstetric anesthesia where clinical management is controversial.

A survey consisting of 47 questions, 40 regarding clinical practice and 7 regarding demographics, was mailed to 153 directors of obstetric anesthesia in academic practice and to 153 anesthesiologists in private practice. Questions relating to the following areas of practice were asked: 1) preoperative laboratory testing; 2) preeclampsia and possible coagulopathies; 3) epidural catheter placement in women with "spinal problems"; and 4) use of epidural opioids and intravenous supplementation. Surveys were returned by 113 (74%) academic anesthesiologists and 94 (61%) private practice anesthesiologists. By univariate analysis, 14 questions showed a significant difference in response between those in academic and private practice, but only eight remained significant after accounting for the amount of clinical time currently devoted to obstetric anesthesia (>50% or < or = 50%). These eight questions related to preoperative laboratory testing in the healthy parturient, preoperative laboratory testing in the preeclamptic patient, and the use of intravenous supplementation during a cesarean section with regional anesthesia. Although there were some differences in the responses between anesthesiologists in academic and private practice, overall the responses were similar.

The visual analog scale for pain: clinical significance in postoperative patients.

BACKGROUND: The visual analog scale is widely used in research studies, but its connection with clinical experience outside the research setting and the best way to administer the VAS forms are not well established. This study defines changes in dosing of intravenous patient-controlled analgesia as a clinically relevant outcome and compares it with VAS measures of postoperative pain. METHODS: Visual analog scale measurements were obtained from 150 patients on the morning after intraabdominal surgery. On the same afternoon, 50 of the patients provided a VAS score on the same form used in the morning, 50 on a new form, and 50 were not asked for a second VAS measurement. RESULTS: Visual analog scale values and changes in value were similar for patients who were given a new VAS form in the afternoon and those who used the form that showed the morning value. The proportions of patients requesting additional analgesia were 4, 43, and 80%, corresponding to afternoon VAS scores of 30 or less, 31-70, and greater than 70, respectively. Change from morning VAS score had no apparent influence on patient-controlled analgesic dosing for patients with afternoon values of 30 or less or greater than 70, but changes in VAS scores of at least 10 did discriminate among patients whose afternoon values were between 31 and 70. CONCLUSIONS: When pain is an outcome measure in research studies, grouping final VAS scores into a small number of categories provides greater clinical relevance for comparisons than using the full spectrum of measured values or changes in value. Seeing an earlier VAS form has no apparent influence on later values.

Improved epidural analgesia in the parturient in the 30 degree tilt position.

PURPOSE: To compare the incidence of incomplete analgesia when epidural local anesthetic is administered with the parturient supine in a 30 degree leftward tilt or in the left lateral decubitus position. METHODS: After placement of a multiorifice catheter 5 cm into the epidural space, 293 women in active labour were randomly positioned either to the left lateral decubitus position (lateral group) or supine with a 30 degree leftward tilt (tilt group) and then received 13 mL bupivacaine 0.25%. The success of the epidural block was determined by asking the patient if she required additional medication 15 min later. The incidence of complications (fetal heart rate decelerations, hypotension, and ephedrine usage) was noted. RESULTS: In the lateral group, 38% required additional medication compared with 24% in the tilt group (P = 0.006). There were no differences between groups in the incidence of maternal hypotension or fetal heart rate decelerations, but more women (10%) received ephedrine in the lateral than in the tilt group (4%), P = 0.035. CONCLUSIONS: Placing the parturient supine with a 30 degree leftward tilt is associated with a greater success rate of labour epidural analgesia without an increase in complications than in women in the left lateral decubitus position. This advantage should be considered when positioning the parturient after epidural catheter placement.