Epidural catheter-induced paresthesia accompanied by changes in skin color and temperature in an obstetric patient.

Placement of epidural catheters for labor analgesia is a common procedure that has become more popular in recent years. However, this procedure can often cause paresthesia, which is typically characterized as a transient and intense burning pain radiating to the hip or leg. In this case report, we describe a patient who had persistent paresthesia in her right foot caused by an indwelling epidural catheter, which was successfully relieved following a partial withdrawal of the epidural catheter. More interestingly, we also observed dramatic changes in skin color and temperature (cold and pale) on her right foot that was well correlated both in time and location with the epidural-induced paresthesia. This cold and pale skin on the right foot represents a localized sympathetic discharge associated with the epidural-induced paresthesia, a phenomenon that has not previously been described. Based on the location of the paresthesia and the pathway of the sympathetic nerve fibers, it is unlikely that this localized sympathetic discharge was due to a direct irritation of the preganglionic sympathetic fibers in the spinal nerve roots by the epidural catheter and thus, a spinal reflex was probably involved. This phenomenon provided us with additional clinical evidence of nerve root irritation, which prompted us to act quickly, and resulted in a favorable outcome.

Medical science and social values.

Social Values, no less than medical science, have shaped the medical management of the pain of childbirth. Nineteenth century feminists fought for greater use of anesthesia in obstetrics at a time when physicians held back for fear of its effects on labor, hemorrhage, rates of infection and the condition of the child. A century later, after physicians became comfortable with the use of anesthesia, a new generation of feminists challenged the use of such drugs, once again citing social considerations. The personalities of colorful and charismatic obstetricians such as James Young Simpson and Grantley Dick-Read played a strong part in the outcome of each confrontation.

Beta-cell crosstalk: a further dimension in the stimulus-secretion coupling of glucose-induced insulin release.

Pancreatic beta-cells are connected by gap junction channels made of a connexin protein, referred to as Cx36. Through these channels, beta-cells are coupled to each other, i.e. exchange cytoplasmic ions and small metabolites. Previous experiments have indicated that these exchanges are important for coordinating the function of individual cells within pancreatic islets, particularly with regard to glucose-induced insulin secretion. Advances in molecular biology, genetics and mouse transgenic approaches allow now for a direct experimental testing of this mechanism in vitro as well as in vivo. Recent experiments in rodent and culture models suggest that connexin-dependent cell-to-cell crosstalk is a significant player in the multifactorial regulation of insulin secretion and, possibly, of other beta-cell functions, such as growth. Elucidating the still obscure mechanism whereby connexin signalling exerts this influence will provide insights on the contribution of direct cell-to-cell interactions in the physiological regulation of beta-cell life. The presence of Cx36 within human pancreatic islets, raises the further challenge to determine whether a dysfunction of connexin signaling may contribute to the pathophysiology of beta-cell dysfunctions in type I and/or type II diabetes. Efforts to understand the functions of beta-cell connexins are also a prerequisite for the engineering of surrogate cells and their proper tridimensional packaging, which are instrumental for the future implementation of a replacement cell therapy in diabetic patients.

Pioneers in epidural needle design.

IMPLICATIONS: In this article we discuss the development of epidural needles and the historical factors leading to their invention. The most popular needles are described and their inventors acknowledged.

Cx36 and the function of endocrine pancreas.

The secretory, duct, connective and vascular cells of pancreas are connected by gap junctions, made of different connexins. The insulin-producing beta-cells, which form the bulk of endocrine pancreatic islets, express predominantly Cx36. To assess the function of this connexin, we have first studied its expression in rats, during sequential changes of pancreatic function which were induced by the implantation of a secreting insulinoma. We observed that changes in beta-cell function were paralleled by changes in Cx36 expression. We have also begun to investigate mutant mice lacking Cx36. The absence of this protein did not affect the development and differentiation of beta-cells but appeared to alter their secretion. We have studied this effect in MIN6 cells which spontaneously express Cx36. After stable transfection of a construct that markedly reduced the expression of this connexin, we observed that MIN6 cells were no more able to secrete insulin, in contrast to wild type controls, and differentially displayed a series of still unknown genes. The data provide evidence that Cx36-dependent signaling contributes to regulate the function of native and tumoral insulin-producing cells.

John Snow's practice of obstetric anesthesia.

The influence of Queen Victoria on the acceptance of obstetric anesthesia has been overstated, and the role of John Snow has been somewhat overlooked. It was his meticulous, careful approach and his clinical skills that influenced many of his colleagues, Tyler-Smith and Ramsbotham and the Queen's own physicians. The fact that the Queen received anesthesia was a manifestation that the conversion of Snow's colleagues had already taken place. This is not to say that this precipitated a revolution in practice. Medical theory may have changed, but practice did not, and the actual number of women anesthetized for childbirth remained quite low. This, however, was a reflection of economic and logistical problems, too few women were delivered of newborn infants during the care of physicians or in hospitals. Conversely, it is important to recognize that John Snow succeeded in lifting theoretical restrictions on the use of anesthesia.

Modeling obstetric cardiovascular physiology on a full-scale patient simulator.

To our knowledge, this is the first attempt at adapting an existing cardiovascular model to simulate the hemodynamics of a particular patient population. Despite attempts to define the physiologic alterations in advance, we discovered there were critical parameters not completely defined in the literature. These were discovered through the iterative process of testing, comparing resulting vital signs with targets, and literature review. A list of the parameters that should be sought for future modeling efforts is provided (Table 3), but this list is by no means exhaustive. As further work is performed in this area, additional independent and essential parameters will be identified (pressure characteristics of valvular anomalies, for example). To define a physiology that is less well described in the literature, empirical alterations and best-guess estimates of parameter changes will be required with significantly more iterations. Finally, we have described only modeling of cardiovascular physiology, modeling the respiratory system will require a similar process.

The practical use of carbon dioxide-induced anxiety in the diagnosis and care of patients with panic disorder.

The authors utilized inhalation of 35% carbon dioxide and 65% oxygen as a diagnostic tool in the evaluation of suspected panic disorder. In two inpatients admitted for a medical evaluation for pheochromocytoma and carcinoid syndrome, respectively, a positive response to the double-blind administration of CO2/O2 or room air was consistent with a diagnosis of panic disorder by psychiatric history. In two additional patients in whom denial of mental illness was a psychological impediment to proper treatment, a positive CO2/O2 challenge resulted in therapeutic benefit.

Technical note: subjective enumeration of episodic events (spikes) in animal physiology experiments.

Blood samples of nine sheep were taken over time and analyzed for estrone, estradiol, and progesterone. Results were plotted for each sheep, and graphs were evaluated by 26 evaluators with various previous experience. Sheep were sampled for different time periods. Repeatabilities for the number of spikes of estrone, estradiol, and progesterone recorded for sheep were variable, ranging from .019 to .547. Repeatabilities for evaluators ranged from .033 to .427, but these values decreased to < .001 to .030 when adjusted by covariance for the number of spikes possible. Results indicated that either an objective procedure for counting spikes should be used in comparable research or that evaluators should be trained in visual counting procedures to improve their repeatability.

Patterns of variation in progestin in pregnant sheep.

Patterns of variation in progestin concentrations were studied in pregnant sheep during the last half of gestation. In three sets of experiments, blood was drawn daily or every 4 h for 24 h or every 10 min for 8 h. Peripheral arterial concentration of progestin was examined for 'peaks' using the Pulsar program which identified peaks in daily samples and in samples collected every 10 min, though less often than in daily samples. Ovariectomy did not affect the frequency or character of the peaks. The data suggest that large variations in progestin concentrations occur during the last half of pregnancy. They are superimposed on a gradual increase in average concentration and last for 2 to 3 days.

Maturational and anesthetic effects on apneic thresholds in lambs.

Periods of apnea are relatively common in newborns but rare in older infants. Postnatal changes in the response of the central neural respiratory circuits to afferent inputs may have a role in the age-related incidence of apnea. Therefore we determined the central neural apneic threshold to CO2 and superior laryngeal nerve (SLN) stimulation in halothane-anesthetized newborn (4- to 7-day-old) and older (45- to 56-day-old) lambs. The animals were vagotomized, paralyzed, and mechanically ventilated with hyperoxic gas. Phrenic nerve activity served as a monitor of central respiratory output. The CO2 and SLN apneic thresholds were defined as the arterial PCO2 when phrenic activity began after hyperventilation, and the quantity of current applied to the SLN that abolished phrenic activity, respectively. At equivalent concentrations of halothane, newborn lambs had higher CO2 apneic thresholds (P less than 0.05) and lower SLN apneic thresholds (P less than 0.05) than did older lambs. Increasing concentrations of halothane decreased (P less than 0.05) the SLN apneic threshold and increased (P less than 0.05) the CO2 apneic threshold. Equal incremental changes in halothane concentration induced similar changes in the apneic thresholds of both ages of lambs. The data suggest that with maturation, the central neural respiratory circuits become more responsive to CO2 and less responsive to SLN afferents. Halothane alters central neural responsiveness to these inputs in both ages similarly.

Cardiac output in women undergoing cesarean section with epidural or general anesthesia.

Cardiac output during cesarean section and for 24 hours after delivery was estimated by using a noninvasive ultrasonic Doppler technique and was compared between term pregnant patients who underwent either epidural or general anesthesia. Cardiac output peaked by 36.7% and 26.3% of baseline values at 15 and 30 minutes after delivery, respectively, with epidural anesthesia and by 28% and 17.2%, respectively, with general anesthesia. From 60 minutes to 24 hours after delivery, cardiac output in both groups remained elevated at preoperative levels. This study demonstrates a similar pattern of increase in cardiac output with epidural and general anesthesia and a return by 60 minutes to preoperative levels, which persisted for up to 24 hours after delivery. The applicability of this noninvasive technique can be extended in various circumstances during pregnancy, labor, delivery, and the postpartum period to further define cardiac output in pregnancy.

Anesthetic management for obstetric hysterectomy: a multi-institutional study.

A prospectively designed review of all obstetric hysterectomies performed in five university hospitals between November 1, 1984 and October 31, 1987 has been performed. There were 41,107 deliveries and 46 obstetric hysterectomies, an incidence of 0.11%. Twenty-five hysterectomies were elective and 21 were emergent. The indication for 11 of the 21 emergency hysterectomies was placenta previa and/or accreta. Women in the emergency group had greater intraoperative blood loss, were more likely to have intraoperative hypotension, and were more likely to receive donor blood than women in the elective group (P less than 0.05). Twelve patients (eight from the elective group and four from the emergency group) received continuous epidural anesthesia, and none required intraoperative induction of general anesthesia. There was no evidence that epidural anesthesia significantly affected blood loss, crystalloid replacement, or requirement for transfusion in the elective group. Abnormal placentation now represents a major indication for emergency obstetric hysterectomy. Furthermore, significant hemorrhage is more likely with emergency obstetric hysterectomy than with elective hysterectomy. Finally, elective cesarean hysterectomy is not a contraindication to performance of continuous epidural anesthesia.

Burnout and stress among employees at a state institution for mentally retarded persons.

The effects of burnout of 192 employees of a state institution were examined to determine whether these problems were different from conditions resulting from stress. Each subject completed a packet including the Maslach Burnout Inventory and Ivancevich's Job Stress Scale. For all groups, high burnout emerged in the form of low personal accomplishment, with moderate degrees of burnout measured by the Burnout Inventory subscales Emotional Exhaustion and Depersonalization. One of the stress variables (underutilization) correlated significantly with one Burnout Inventory subscale (Emotional Exhaustion). Results generally indicated that stress and burnout were separate constructs that can be best thought of as distinct entities.

Conceptus development, uterine response, blood gases and endocrine function of gilts exposed to increased ambient temperature during early pregnancy.

Fifteen crossbred gilts were used to determine the influence of heat stress during Days 8 to 16 after onset of estrus on the development of conceptuses and uterine and endocrine functions. Ten gilts were bred 12 and 24 h after the onset of estrus (Day 0), and five gilts were nonbred controls. On Day 5, catheters were inserted into the uterine-ovarian vein (UV), saphenous artery (SA) and saphenous vein (SV) of each gilt. An electromagnetic blood flow transducer was implanted around the main uterine artery. Pregnant (n=5) and nonbred (n=5) control gilts were exposed to 21 +/- 1 degrees C, and pregnant heat-stressed gilts (n=5) were exposed to 37 +/- 1 degrees C for 12 h and 32 +/- 1 degrees C for 12 h daily during Days 8 through 16 after estrus. Treatment did not influence the partial pressure of oxygen (PO(2)) and of carbon dioxide (PCO(2)) in the UV, SA and SV blood. Uterine blood flow was not altered by heat stress. On Day 16, total wet weight of conceptuses was reduced in the gilts that were heat-stressed compared with conceptuses from control gilts. Incorporation of (3)H-leucine into macromolecules in vitro by conceptuses from the heat-stressed gilts was reduced compared with control gilts. Concentrations of 15-keto-13, 14-dihydro prostaglandin F(2alpha) (PGFM) in peripheral blood were greater than 1 ng/ml between Days 13 to 16 after estrus in 20% of the pregnant control gilts, 60% of the heat-stressed pregnant gilts, and 100% of the nonbred gilts. Concentrations of estradiol in the SA were affected by treatment. These results indicate that heat stress of gilts between Days 8 to 16 after estrus reduced the amount of conceptus tissue and altered concentrations of estradiol in the peripheral circulation, but uterine blood flow and PO(2) and PCO(2) in blood were not affected.