Katherine W. Arendt

Cardiopulmonary Bypass During Pregnancy

BACKGROUND Cardiac surgery during pregnancy carries significant maternal and fetal risk and is typically considered after failure of medical therapy. We sought to determine the maternal and neonatal outcomes of cardiopulmonary bypass during pregnancy. METHODS Twenty-one pregnant patients undergoing cardiothoracic surgery were identified from the Mayo Clinic surgical database (1976 to 2009). Maternal and neonatal outcomes were reviewed. RESULTS Operations included 8 aortic valve replacements, 6 mitral valve repair-replacements, 2 myxoma excisions, 1 patent foramen ovale closure, 1 myectomy, 2 aortic aneurysm repairs, and 1 prosthetic aortic valve thrombectomy. Median cardiopulmonary bypass time was 53 minutes (range 16 to 185). Twelve patients (57%) required emergent surgery with a median gestational age (GA) of 25 weeks (range 7 to 35.5). Seven patients underwent cesarean section immediately prior to sternotomy delivering viable infants (median GA 31 weeks). In the remaining patients, three additional preterm births occurred, all in operations performed at an early GA (13 to 15 weeks). Median follow-up was 16 months (range 3 to 305). All patients improved to New York Heart Association functional class I or II. One early maternal death occurred 2 days after emergent mechanical aortic valve thrombectomy and 3 late maternal deaths occurred 2, 10, and 19 years postoperatively. Three fetal deaths occurred in mothers with additional medical comorbidities. CONCLUSIONS In the current era, cardiothoracic surgery can be performed with relative safety during pregnancy. Fetal complications (prematurity and death) are associated with urgent, high-risk surgery, maternal comorbidity, and early GA. Emergent surgery appears to confer a higher risk of maternal death.

Atraumatic lumbar puncture needles: after all these years, are we still missing the point?

Background:Cutting needles remain the most commonly used needle design for lumbar puncture in the neurology community, although atraumatic (noncutting) needles have become common and popular for anesthesiologists performing spinal anesthesia. Review Summary:The use of atraumatic spinal needles for lumbar puncture has been shown to significantly reduce the incidence of postdural puncture headache compared with cutting needles, without loss of efficacy or ease of use. Conclusion:The use of noncutting or pencil-point spinal needles should become the standard for performing diagnostic lumbar puncture.

Pregnant women with congenital heart disease: cardiac, anesthetic and obstetrical implications

Remarkable advances in surgical and clinical management have resulted in survival to adulthood in the large majority of patients with congenital heart malformations, even with the most complex disease. Over 1 million adults with congenital heart disease currently live in the USA, approximately half of whom are women of childbearing age. Collectively, congenital malformations are the most common form of heart disease in pregnant women. Indeed, in North America, congenital defects are now the leading cause of maternal morbidity and mortality from heart disease. This article begins with a summary of cardiovascular changes during pregnancy and highlights key features in pre-pregnancy counseling, maternal cardiac and obstetric risk, and neonatal complications. Management issues regarding pregnancy and delivery are elaborated, including anesthesia considerations. While it is beyond the scope of this article to discuss particulars related to all forms of congenital heart disease, selected subtypes are detailed at greater length. In the absence of clinical trial evidence to inform the care of pregnant women with congenital heart disease, this article is inspired by the premise that knowledgeable multidisciplinary assessment and management provides the best opportunity to substantially improve outcomes for mother and baby.

Neurologic complications after chlorhexidine antisepsis for spinal anesthesia

Background and Objectives Recent reports of infectious complications after neuraxial procedures highlight the importance of scrupulous aseptic technique. Although chlorhexidine gluconate (CHG) has several advantages over other antiseptic agents; including a more rapid onset of action, an extended duration of effect, and rare bacterial resistance, it is not approved by the US Food and Drug Administration for use before lumbar puncture because of absence of clinical safety evidence. The objective of this retrospective cohort study was to test the hypothesis that the incidence of neurologic complications associated with spinal anesthesia after CHG skin antisepsis is not different than the known incidence of neurologic complications associated with spinal anesthesia. Methods All patients 18 years or older who underwent spinal anesthesia at Mayo Clinic Rochester from 2006 to 2010 were identified. The primary outcome variable was the presence of any new or progressive neurologic deficit documented within 7 days of spinal anesthesia. The etiology of a patient’s neurologic complication was independently categorized as possibly or unlikely related to the spinal anesthetic by 3 investigators. Consensus among all reviewers was required for final category assignment. Results A total of 11,095 patients received 12,465 spinal anesthetics during the study period. Overall, 57 cases (0.46%; 95% confidence interval, 0.34%–0.58%) met criteria for neurologic complication. Spinal anesthesia was felt to be the possible etiology of 5 neurologic complications (0.04%; 95% confidence interval, 0.00%–0.08%); all completely resolved within 30 days. Discussion The incidence of neurologic complications possibly associated with spinal anesthesia (0.04%) after CHG skin antisepsis is consistent with previous reports of neurologic complications after spinal anesthesia. These results support the hypothesis that CHG can be used for skin antisepsis before spinal placement without increasing the risk of neurologic complications attributed to the spinal anesthetic.

A retrospective effectiveness study of loss of resistance to air or saline for identification of the epidural space.

BACKGROUND: Randomized trials comparing air to saline for loss of resistance (LOR) for identification of the epidural space have suggested the superiority of saline. We hypothesized that, in actual clinical practice, anesthesiologists using their preferred technique would produce similar analgesic outcomes with either air or saline. METHODS: The labor analgesia records for 929 parturients requesting neuraxial analgesia were reviewed with respect to technique (epidural or combined spinal-epidural; air or saline for LOR), analgesic outcomes (initial comfort, asymmetry of the block, need for physician top-up during patient-controlled epidural analgesia, and catheter replacement), and complications (paresthesia, IV or intrathecal catheter placement, and unintentional dural puncture). RESULTS: Of 929 labor analgesics analyzed, 52.6% were performed with LOR to air and 47.4% to saline. Among anesthesiologists who performed at least 10 blocks, 82% used 1 medium at least 70% of the time. There were no differences between the air and saline groups in patient characteristics, analgesic technique, or block success. Among operators with a preference for 1 medium, use of the preferred technique was associated with fewer attempts (1.3 ± 0.7 vs 1.6 ± 0.8, P = 0.001), fewer paresthesias (8.7% vs 18.5%, odds ratio = 0.42, P = 0.007), and fewer unintentional dural punctures (1.0% vs 4.4%, odds ratio = 0.23, P = 0.03). CONCLUSIONS: When used at the anesthesiologists discretion, there is no significant difference in block success between air and saline for localization of the epidural space by LOR.

The Association Between Epidural Labor Analgesia and Maternal Fever

The association between epidural labor analgesia and maternal fever is complex and controversial. Observational, retrospective, before-and-after, and randomized controlled trials all support the association, with the most current evidence supporting the mechanistic involvement of noninfectious inflammation. Considering the clinically significant neonatal consequences that have been previously demonstrated, and the possibility of more common subclinical fetal brain injury that animal models imply, the avoidance of maternal fever during labor is imperative. With the current popularity of epidural analgesia in labor, it is important that clinicians delineate how epidurals cause maternal fever and how to block the noninfectious inflammatory response that seems to warm a subset of women laboring with epidurals.

Present and emerging strategies for reducing anesthesia-related maternal morbidity and mortality.

Purpose of review As the demographic of pregnant women continues to change, anesthesiologists will need to continue to find new ways to prevent morbidity and mortality. In this article several new and emerging strategies to meet this challenge are discussed. Recent findings Emergence and recovery are now the most common times for airway loss. The proportion of liability claims involving neuraxial anesthesia have increased. Ultrasound can assist in spinal or epidural anesthesia. The most effective antiseptic is 0.5% chlorhexidine in 80% ethanol, which is generally accepted for use in neuraxial techniques. An animal study indicates that bupivacaine-induced cardiac arrest is more effectively treated by intravenous lipid emulsion than by epinephrine. In obstetric hemorrhage, consideration should be given to 1: 1 FFP: PRBC transfusion, and in severe cases, rFVIIa. Summary Over the past 50 years, the field of anesthesiology has reduced the rates of anesthesia-related maternal mortality and major morbidity considerably. As the obstetric demographic becomes older and more obese, new technologies and strategies can assist in keeping maternal death and major morbidity vanishingly rare.

A case series of the anesthetic management of parturients with surgically repaired tetralogy of Fallot.

BACKGROUND: Most case reports of pregnancies after surgical repair of tetralogy of Fallot have focused on cardiovascular and obstetric concerns, with relatively few authors focusing on specific intrapartum and postpartum anesthetic management strategies. METHODS: The Mayo Clinic Congenital Heart Disease Clinic and the Boston Adult Congenital Heart Disease Service databases were cross-referenced with the Mayo Clinic and the Brigham and Womens Hospital Department of Anesthesiology databases to identify patients with tetralogy of Fallot who delivered at their respective hospital from January 1, 1994, to January 1, 2008. We reviewed each medical record to evaluate parturient care during pregnancy, labor, and delivery with a focus on anesthetic management. RESULTS: During the 14-year study period, a total of 27 deliveries in 20 patients with repaired tetralogy of Fallot were identified. Twenty-one deliveries (78%) among 15 parturients (75%) involved a trial of labor; all parturients received neuraxial analgesia for labor and delivery, including 18 (86%) epidural, 2 (10%) combined spinal–epidural, and 1 (5%) continuous spinal anesthetic after an unintended dural puncture. Of the 21 patients undergoing labor, 3 (14%) received invasive arterial blood pressure monitoring; 5 (24%) received continuous telemetry; 3 (14%) experienced congestive heart failure that required diuresis; 4 (19%) had obstetric or neonatal complications; and 3 (14%) had anesthesia complications. Cesarean delivery was required in 4 patients (19%) because of labor complications. Concurrent cardiovascular, obstetric, and anesthetic complications in 1 patient resulted in neonatal death. Six (22%) parturients underwent elective cesarean delivery; 4 received epidural and 2 received spinal anesthesia; no anesthetic or immediate obstetric complications occurred. Among all parturients, 5 deliveries in 5 separate parturients (19% of deliveries) reported symptoms of congestive heart failure at the time of delivery. CONCLUSIONS: Pregnancy outcomes for patients with repaired tetralogy of Fallot were found to be generally favorable. All patients undergoing a trial of labor or cesarean delivery had neuraxial analgesia or anesthesia. Recognition and management of congestive heart failure was necessary in 19% of deliveries.

Emergency bedside cesarean delivery: lessons learned in teamwork and patient safety

BackgroundMaternal cardiovascular and pulmonary events during labor and delivery may result in adverse maternal and fetal outcome. Potential etiologies include primary cardiac events, pulmonary embolism, eclampsia, maternal hemorrhage, and adverse medication events. Remifentanil patient-controlled analgesia is an alternative when conventional neuraxial analgesia for labor is contraindicated. Although remifentanil is a commonly used analgesic, its use for labor analgesia is not clearly defined.Case presentationWe present an unexpected and unique case of remifentanil toxicity resulting in the need for an emergent bedside cesarean delivery. A 30-year-old G3P2 woman receiving subcutaneous heparin anticoagulation due to a recent deep vein thrombosis developed cardiopulmonary arrest during labor induction due to remifentanil toxicity.ConclusionA rapid discussion among the attending obstetric, anesthesia, and nursing teams resulted in consensus to perform an emergent bedside cesarean delivery resulting in an excellent fetal outcome. During maternal cardiopulmonary arrest, a prompt decision to perform a bedside cesarean delivery is essential to avoid significant maternal and fetal morbidity. Under these conditions, rapid collaboration among obstetric, anesthesia, and nursing personnel, and an extensive multi-layered safety process are integral components to optimize maternal and fetal outcomes.

Nonpharmacologic Labor Analgesia

A supportive medical team should be well informed on the various pharmacologic and nonpharmacologic modalities of coping with or mitigating labor pain to appropriately support and respectfully care for parturients. Using the methodical rigor of previously published Cochrane systematic reviews, this summary evaluates and discusses the efficacy of nonpharmacologic labor analgesic interventions.