Hand placement during chest compressions in parturients: a pilot study to identify the location of the left ventricle using transthoracic echocardiography.

BACKGROUND: Current guidelines for maternal cardiopulmonary resuscitation recommend the hands be placed on the lower half of the sternum for compressions. We sought to evaluate the effect of the gravid uterus and left uterine displacement on the position of the left ventricle (LV) using transthoracic echocardiography. METHODS: We enrolled 20 women in the third trimester of a singleton pregnancy. Transthoracic echocardiography images in the supine and left lateral position, using a 30° wedge, were acquired. Parasternal long and short axis views of the LV were obtained at the lower half of the sternum and at the ideal imaging window (best image of mid-LV at 90° transducer orientation) The primary aim was to evaluate the distance between the distal end of the xiphoid and the location of the best imaging window of the LV. RESULTS: The cohort included women without prior anatomical cardiac disease. The LV was best visualized 5.8 (±2) cm cranial to the distal end of the xiphoid in the supine position and 6.1 (±2) cm in the lateral position (P=0.6), using the left parasternal border as a reference. No lateral cardiac displacement was evidenced in either position. CONCLUSIONS: This pilot study used transthoracic echocardiography to document the position of the LV during the third trimester of pregnancy. The LV was located approximately 6 cm cranial to the distal tip of the xiphoid process. Further validation is required before recommending changes in hand placement during maternal cardiopulmonary resuscitation.

Multimodal general anesthesia approach for Ex Utero Intrapartum Therapy (EXIT) procedures: two case reports.

High-dose volatile anesthesia is the most common method of achieving uterine relaxation for Ex Utero Intrapartum Therapy (EXIT) procedures. Other methods employ nitroglycerin for additional uterine relaxation with or without remifentanil for additional fetal analgesia. We report a combination approach including one minimum alveolar concentration of volatile anesthetic plus nitroglycerin and remifentanil infusions, to provide timely uterine relaxation under general anesthesia for both mother and fetus, during two EXIT procedures.

Osteogenesis imperfecta: cesarean deliveries in identical twins.

Osteogenesis imperfecta is a congenital disorder resulting in multiple fractures and extremely short stature, usually necessitating cesarean delivery. Identical twins with severe osteogenesis imperfecta each of whom underwent a cesarean delivery with different anesthetic modalities are presented. A review of the literature and anesthetic options for cesarean delivery and postoperative analgesia for women with osteogenesis imperfecta are discussed.

Repeated simulation-based training for performing general anesthesia for emergency cesarean delivery: long-term retention and recurring mistakes.

BACKGROUND: The percentage of women undergoing cesarean delivery under general anesthesia has significantly decreased, which limits training opportunities for its safe administration. The purpose of this study was to evaluate how effective simulation-based training was in the learning and long-term retention of skills to perform general anesthesia for an emergent cesarean delivery. METHODS: During an eight-week obstetric anesthesia rotation, 24 residents attended lectures and simulation-based training to perform general anesthesia for emergent cesarean delivery. Performance assessments using a validated weighted scaling system were made during the first (pre-test) and fifth weeks (post-test) of training, and eight months later (post-retention test). Resident's competency level (weighted score) and errors were assessed at each testing session. Six obstetric anesthesia attending physicians, unfamiliar with the simulation scenario, generated a mean attendings' performance score. The results were compared. RESULTS: At one week of training, residents' performance was significantly below mean attendings' performance score (pre-test: 135±22 vs. 159±11, P=0.013). At five weeks, residents' performance was similar to mean attendings' performance score (post-test: 159±21) and remained at that level at eight months (post-retention test: 164±16). Of the important obstetric-specific tasks, left uterine displacement was missed by 46% of residents at eight months. CONCLUSION: Following lectures and simulation-enhanced training, anesthesia residents reached and retained for up to eight months a competency level in a simulator comparable to that of obstetric anesthesia attending physicians. Errors in performance and missed tasks may be used to improve residency training and continuing medical education.

Chronic pain after childbirth.

With over four million deliveries annually in the United States alone and a constant increase in cesarean delivery rate, childbirth is likely to have a huge impact on the occurrence of acute and possibly chronic postpartum pain. Recent awareness that chronic pain may occur after childbirth has prompted clinicians and researchers to investigate this topic. Current evidence points towards a relatively low incidence of chronic pain after cesarean delivery, with rates ranging between 1% and 18%. To provide a potential mechanistic explanation for the relatively low occurrence of chronic pain after cesarean delivery compared with that after other types of surgery, it has been proposed that endogenous secretion of oxytocin may confer specific protection. Clinical interventions to reduce the incidence and severity of chronic post-surgical pain have not been consistently effective. Likely explanations are that the drugs that have been investigated were truly ineffective or that the effect was too modest because with a low incidence of chronic pain, studies were likely to be underpowered and failed to demonstrate an effect. In addition, since not all women require preventive therapies, preoperative testing that may identify women vulnerable to pain may be highly beneficial. Further research is needed to identify valid models that predict persistent pain to allow targeted interventions to women most likely to benefit from more tailored anti-hyperalgesic therapies.

Preoperative scar hyperalgesia is associated with post-operative pain in women undergoing a repeat Caesarean delivery.

BACKGROUND: Over 1.4 million Caesarean deliveries are performed annually in the United States, out of which 30% are elective repeat procedures. Post-operative hyperalgesia is associated with an increased risk for persistent post-surgical pain; however, there are no data on whether residual scar hyperalgesia (SHA) from a previous Caesarean delivery (CD) persists until the next delivery. We hypothesized that residual SHA may be present in a substantial proportion of women and is associated with increased post-operative pain. METHODS: One hundred and sixty-three women scheduled for a repeat CD under spinal anaesthesia were enrolled into the study. Mechanical temporal summation (mTS) and SHA index were measured preoperatively. SHA was considered present when the index was >0. Post-operative pain scores at 12, 24 and 48 h and wound hyperalgesia (WHA) at 48 h were recorded. RESULTS: SHA was present in 67 women 41% with a median SHA index of 0.42 (Q (25) = 0.25; Q (75) = 1.1, range 0.03-4.25). Women with SHA had overall higher post-operative pain scores and SHA was correlated with preoperative mTS (r = 0.164, p < 0.05), post-operative pain severity (r = 0.25, p < 0.002) and WHA at 48 h (r = 0.608, p < 0.001). Severe pain (visual analogue pain scale-S48 ≥ 7, n = 20) was predicted with a sensitivity and specificity of 60% and 62%, respectively. Positive predictive value was 18% and negative predictive value was 92%. CONCLUSIONS: Preoperative SHA is present in 41% of women scheduled for repeat CD and is associated with increased mTS and post-operative pain. Screening for preoperative SHA may predict women at risk for increased post-operative pain, and guide post-operative analgesia to include anti-hyperalgesic drugs.

Pharmacogenetics and anaesthesia: the value of genetic profiling.

Approximately 50 years ago, pharmacogenetics was described as a new field of medicine that may explain human drug action. Anaesthesia played a key role in the early investigations. An understanding of how a person's DNA influences drug metabolism and effectiveness may allow individually tailored prescriptions, improving outcomes and safety. The ultimate goal of pharmacogenetic research is to offer tailored personalised medicine to improve both the efficacy of medication and patient safety by helping to predict risk of adverse outcomes. In this review, we present a selection of historical landmarks where anaesthesia has been a catalyst for pharmacogenetic development. We examine the level of evidence and cite examples of candidate genes and common polymorphisms known to alter the response to peri-operative medication. Finally, we set forth current views and potential exciting perspectives that may arise from the application of pharmacogenetics to the daily practice of anaesthesia and pain medicine.

Transversus abdominis plane catheters for post-cesarean delivery analgesia: a series of five cases.

We present five cases of women who received ultrasound-guided transversus abdominis plane catheters for post-cesarean delivery analgesia. Pain relief was maintained with repeated boluses of local anesthetic combined with oral acetaminophen and ibuprofen unless contraindicated. We conclude that repeated dosing through transversus abdominis plane catheters may be offered to women as an alternative or adjuvant to intrathecal morphine. Larger studies to evaluate the safety and further refinements of this novel procedure are warranted.

Symptomatic mechanical heart valve thrombosis: high morbidity and mortality despite successful treatment options.

BACKGROUND: Recommendations for treatment of mechanical prosthetic heart valve thrombosis (PVT) include systemic thrombolysis and/or reoperation. Data on complications and outcome are limited. METHODS: Clinical and echocardiographic findings of 17 patients with mechanical PVT were reviewed. Complications and outcome of surgery and/or thrombolysis were analysed. Prospective follow-up was obtained. RESULTS: Symptomatic PVT occurred 8.4 +/- 7.2 years after mechanical valve replacement at mean age 55 +/- 15 years. Thrombosis involved the mitral valve in 12 patients (71%), the aortic valve in 4 (24%) and the tricuspid valve in one (6%). The reason for PVT was inadequate anticoagulation in 11 patients (65%), endomyocardial fibrosis in 2 (12%) and unknown in 4 (24%). Prior to diagnosis, systemic emboli occurred in 6 patients (35%). Thirteen patients (76%) presented in functional class NYHA IV. Haemodynamic valve obstruction was documented by echocardiography in 15 patients (88%). Treatment included primary reoperation in 12 patients (71%), thrombolysis with urokinase in 3 (18%) (with reoperation in 1), reinstitution of adequate anticoagulation in one (6%); death occurred before treatment in one (6%). Intraoperatively, both pannus and thrombus were found in 5 of 13 patients (38%). Treatment-related emboli occurred in 5 patients (29%), to the brain in 3, to the legs in one and to a coronary artery in one. Five patients died (mortality 29%) within 30 days due to multiorgan failure/septicaemia (3 patients), congestive heart failure (1), or cerebral emboli (1). Follow-up after 28 +/- 28 months in the 12 surviving patients was unremarkable. CONCLUSIONS: The most common aetiology for obstructive PVT is thrombus formation due to inadequate anticoagulation. PVT remains a serious complication with high morbidity and mortality despite aggressive treatment by thrombolysis and/or surgery. Surgery is often needed due to the frequent presence of pannus and/or large thrombi. However, long-term prognosis after successful treatment of PVT is excellent.