Spinal anesthesia for intrapartum Cesarean delivery following epidural labor analgesia: a retrospective cohort study

Purpose

Failed conversion of epidural labor analgesia (ELA) to epidural surgical anesthesia (ESA) for intrapartum Cesarean delivery (CD) has been observed in clinical practice. However, spinal anesthesia (SA) in parturients experiencing failed conversion of ELA to ESA has been associated with an increased incidence of serious side effects. In this retrospective cohort analysis, we examined our routine clinical practice of removing the in situ epidural, rather than attempting to convert to ESA, prior to administering SA for intrapartum CD.

Methods

Hemodynamic data, frequencies of either high or total spinal block, and maternal and neonatal outcome data were gathered from the anesthesia records of all parturients at the Amphia Hospital, undergoing intrapartum CD between January 1, 2001 and May 1, 2005.

Results

Complete data were available for 693 patients (97.6%) of the 710 medical records that were identified. Of the 693 patients, 508 (73.3%) had no ELA and received SA, 128 patients (18.5%) received SA following epidural anesthesia for labor, 19 (2.7%) underwent conversion of ELA to ESA, and 38 (5.5%) received general anesthesia. When comparing both SA groups, no clinically relevant differences were observed regarding the incidence of total spinal block (0% in both groups) or high spinal block (0.2 vs 0.8%, P = 0.36). The number of hypotensive episodes, the total amount of ephedrine administered, and the Apgar scores recorded at 5 and 10 min were similar amongst groups.

Conclusions

The incidence of serious side effects associated with SA for intrapartum CD following ELA is low and not different compared to SA only.     

Coordination of gaze and hand movements for tracking and tracing in 3D

In this study we have investigated movements in three-dimensional space. Since most studies have investigated planar movements (like ellipses, cloverleaf shapes and “figure eights”) we have compared two generalizations of the two-thirds power law to three dimensions. In particular we have tested whether the two-thirds power law could be best described by tangential velocity and curvature in a plane (compatible with the idea of planar segmentation) or whether tangential velocity and curvature should be calculated in three dimensions. We defined total curvature in three dimensions as the square root of the sum of curvature squared and torsion squared. The results demonstrate that most of the variance is explained by tangential velocity and total curvature. This indicates that all three orthogonal components of movements in 3D are equally important and that movements are truly 3D and do not reflect a concatenation of 2D planar movement segments.In addition, we have studied the coordination of eye and hand movements in 3D by measuring binocular eye movements while subjects move the finger along a curved path. The results show that the directional component and finger position almost superimpose when subjects track a target moving in 3D. However, the vergence component of gaze leads finger position by about 250 msec. For drawing (tracing) the path of a visible 3D shape, the directional component of gaze leads finger position by about 225 msec, and the vergence component leads finger position by about 400 msec. These results are compatible with the idea that gaze leads hand position during drawing movement to assist prediction and planning of hand position in 3D space.     

A simplified approach to vertical infraclavicular brachial plexus blockade using hand-held Doppler

In this observational study, we used Doppler ultrasound during the performance of vertical infraclavicular brachial plexus blockade. The success rate at inserting the needle at the point where the sound of the subclavian artery via Doppler reached its maximum audibility was compared with that of the classical insertion point. In 89 of the 100 patients, the medial or posterior cord was found at first needle pass. Using the Doppler point for insertion resulted in a significantly more lateral entry point compared with the classical point (P < 0.001) and was associated with a high success rate of infraclavicular block.     

Aging and heart failure--similar syndromes of exercise intolerance? Implications for exercise-based interventions

A classic hallmark of chronic heart failure (CHF) is exercise intolerance; however, the extent of exercise limitation is not correlated with the degree of left ventricular dysfunction. Over the past 2 decades it has become more and more evident that peripheral factors, such as skeletal muscle dysfunction, ventilatory abnormalities, and endothelial dysfunction, contribute the greater part to the limitation of exercise capacity. The molecular and pathophysiological changes observed in these organ systems are not always specific to the underlying CHF but rather represent a common pathway that is activated in several chronic disease processes, including severe chronic obstructive pulmonary disease, cancer, and in the normal aging process. A major contributing factor for skeletal muscle catabolism (i.e. elevated cytokine expression in the skeletal muscle) can be found in both normal healthy aging and in heart failure patients. It is reasonable to assume that the overlap of aging and CHF-associated changes in the skeletal muscle partially explains the disabling consequences of the CHF syndrome among elderly patients (nearly 80% of all patients hospitalized for CHF are >65 years old). Peripheral alterations in CHF are often not adequately treated in routine clinical care since standard pharmacological therapy is still focused on the cardiac function and neurohormonal alteration. Exercise training is a guideline-oriented adjuvant therapy with well-documented beneficial effects on exercise tolerance, skeletal muscle function, endothelial function, and respiration. In this review, the effects of exercise in aging and in CHF are compared and the parallel mechanisms are explored.     

Promoting Condom Use With Main Partners: A Behavioral Intervention Trial for Women

The Stages of Change (SOC) model was used to implement and evaluate a condom promotion intervention for HIV-positive and at-risk women who were recruited from clinic and community settings in Baltimore and Philadelphia. Participants were assigned to receive standard reproductive health services or enhanced services (standard plus SOC peer advocate intervention). Women who had a main partner at baseline and at a 6-month follow-up were included in the analysis (70 HIV positive, 471 at risk). Compared with the standard group, HIV-positive women in the enhanced group were significantly more likely to have progressed in the SOC model or to have maintained consistent condom use, and less likely to have relapsed or stayed in the precontemplation stage. Among the at-risk women, exposure to the intervention was associated with being at a higher SOC and being less likely to relapse relative to the standard group. The SOC model has promise for use in social and public health service settings that serve women at risk or living with HIV.     

Exercise training in coronary artery disease and coronary vasomotion

Exercise training has assumed a major role in cardiac rehabilitation, mostly because of its positive effects on myocardial perfusion in patients with coronary artery disease. The mechanisms involved in mediating this key effect have long been debated: both regression of coronary artery stenosis and improvement of collateralization have been suggested as potential adaptations. However, the comparatively minute changes in luminal diameter and myocardial contrast staining do not fully explain the significant changes in myocardial perfusion. During the last decade, endothelial dysfunction was identified as a trigger of myocardial ischemia. The impaired production of endothelium-derived nitric oxide (NO) in response to acetylcholine and flow leads to paradoxic vasoconstriction and exercise-induced ischemia. Recently, it was confirmed in humans that training attenuates paradoxic vasoconstriction in coronary artery disease and increases coronary blood flow in response to acetylcholine. Data from cell-culture and animal experiments suggest that shear stress acts as a stimulus for the endothelium to increase the transport capacity for L-arginine (the precursor molecule for NO), to enhance NO synthase activity and expression, and to increase the production of extracellular superoxide dismutase, which prevents premature breakdown of NO. Exercise also affects the microcirculation, where it sensitizes resistance arteries for the vasodilatory effects of adenosine. These novel findings provide a pathophysiological framework to explain the improvement of myocardial perfusion in the absence of changes in baseline coronary artery diameter. Because endothelial dysfunction has been identified as a predictor of coronary events, exercise may contribute to the long-term reduction of cardiovascular morbidity and mortality.