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PubMed1989

Independent measurement of oxygen consumption and oxygen delivery.

This experiment investigated the relationship between oxygen consumption and oxygen delivery (cardiac output X arterial oxygen content) in an acute canine model. Previous studies investigating this relationship have largely utilized methods in which oxygen consumption and oxygen delivery were each calculated using the same measured variables resulting in mathematical coupling of variables. In this study, oxygen consumption was measured directly by closed-circuit spirometry. Oxygen delivery was independently controlled using right atrial bypass. These techniques assured that the values for oxygen consumption and oxygen delivery were derived entirely independently. In our study using 11 dogs, we found that oxygen consumption was constant and independent of oxygen delivery at oxygen delivery levels greater than 8.0 cc/kg/min (normal canine oxygen delivery 20-25 cc/kg/min). Oxygen consumption was linearly related to oxygen delivery at oxygen delivery levels less than or equal to 8.0 cc/kg/min. Below this critical level of oxygen delivery, animals were more acidotic and hypotensive than at higher delivery levels.

Animals↗
PubMed1996

A comparative study on breech deliveries attended in 1992: hospital centers from Latin America versus Spain and Portugal.

OBJECTIVES: The first aim of this study was to compare the incidence and management of breech deliveries, as well as perinatal mortality rates, in centers from Latin America versus Spain and Portugal in Europe. A second aim of this study was to analyse the correlation between the rates of c-sections and perinatal mortality. METHODS: Data from 287 313 deliveries, 8,764 of which were singleton breech deliveries attended in 1992 in 30 centers from Latin America and 44 centers from Spain and Portugal, were provided by the doctors in charge of the obstetric services and analysed using a computer statistical package (R-sigma, Horus Hardware). RESULTS: The incidence of breech deliveries was lower in centers from Latin America than in Spain and Portugal, 2.6% vs. 3.7%, respectively, but the percentage of preterm breech deliveries was higher in the former (23% vs. 17%; P < 0.001). In the total number of deliveries, c-sections were performed more frequently in Latin America, but the perinatal mortality rates were triple those in Spain and Portugal. In breech presentations from both geographical areas nearly 70% of c-sections were performed. However, the perinatal mortality rates in breech presentations were more than twice those of the total number of deliveries in Latin America, and more than three times in Spain and Portugal. There was no correlation between percentage of c-sections and perinatal mortality rates in the different centers in Spain and Portugal, but this correlation was significantly negative in both all and breech deliveries from centers in Latin America. Breech deliveries were more frequently monitored and attended by a specialist in Spain and Portugal. CONCLUSIONS: Preterm deliveries, c-sections and perinatal mortality were more frequent, and the correlation between these two latter rates was significantly negative for both all and breech deliveries in Latin America. As long as basic health care is still an issue in certain countries, it seems that a high rate of c-sections could prevent or reduce perinatal mortality. Yet, in countries with better health care standards, there is probably no need to perform c-section in most breech presentations.

Breech Presentation↗
PubMed1995

A computer-controlled conformal radiotherapy system. III: Graphical simulation and monitoring of treatment delivery.

PURPOSE: Safe and efficient delivery of radiotherapy using computer-controlled machines requires new procedures to design and verify the actual delivery of these treatments. Graphical simulation and monitoring techniques for treatment delivery have been developed for this purpose. METHODS AND MATERIALS: A graphics-based simulator of the treatment machine and a set of procedures for creating and manipulating treatment delivery scripts are used to simulate machine motions, detect collisions, and monitor machine positions during treatment. The treatment delivery simulator is composed of four components: a three-dimensional dynamic model of the treatment machine; a motion simulation and collision detection algorithm, user-interface widgets that mimic the treatment machine's control and readout devices; and an icon-based interface for creating and manipulating treatment delivery scripts. These components are used in a stand-alone fashion for interactive treatment delivery planning and integrated with a machine control system for treatment implementation and monitoring. RESULTS: A graphics-based treatment delivery simulator and a set of procedures for planning and monitoring computer-controlled treatment delivery have been developed and implemented as part of a comprehensive computer-controlled conformal radiotherapy system. To date, these techniques have been used to design and help monitor computer-controlled treatments on a radiotherapy machine for more than 200 patients. Examples using these techniques for treatment delivery planning and on-line monitoring of machine motions during therapy are described. CONCLUSION: A system that provides interactive graphics-based tools for defining the sequence of machine motions, simulating treatment delivery including collision detection, and presenting the therapists with continual visual feedback from the treatment machine has been successfully implemented for routine clinical use as part of an overall system for computer-controlled conformal radiotherapy treatment, and is considered a necessary part of the routine treatment methodology.

Computer Graphics↗
PubMed2006

Timing of scheduled cesarean delivery in patients on a teaching versus private service: adherence to American College of Obstetricians and Gynecologists guidelines and neonatal outcomes.

OBJECTIVE: The purpose of this study was to compare adherence to American College of Obstetricians and Gynecologists guidelines for the timing of scheduled cesarean delivery in patients of a resident teaching service and patients of a private service to determine the neonatal intensive care unit admission rate and the most frequent admission diagnoses after scheduled cesarean delivery and to compare neonatal outcomes between the groups. STUDY DESIGN: A retrospective cohort was reviewed by medical record at a tertiary care center. The cases of 609 patients who were delivered by scheduled cesarean delivery were reviewed, and 296 patients were included. Data regarding demographics, dating, delivery, and outcome were collected and compared with the use of statistical software. RESULTS: Significant differences were noted between patients of a teaching service and patients of a private service, with respect to patient age (26.9 vs 30.7 years; P < .001), body mass index (33.7 vs 31.9 kg/m2; P = .030), race (40.4% white patients in resident teaching services vs 86.0% white patients in private services; P < .001), primary elective cesarean delivery (4 vs 23 deliveries; P = .013), and adherence to American College of Obstetricians and Gynecologists guidelines for the timing of elective delivery (96.3% vs 62%; P < .001), with no significant difference in number of neonatal intensive care unit admissions, severity of neonatal disease, or length of stay in the neonatal intensive care unit. The overall neonatal intensive care unit admission rate for all deliveries by scheduled cesarean delivery was 3.7%. The most frequent neonatal intensive care unit admission diagnoses were hypoglycemia and transient tachypnea of the newborn infant, with no severe sequelae of prematurity in either group. When controlled for fetal anomalies and infants who were born to pregestational diabetic mothers, no significant differences in number of admissions or outcomes were noted; however, 50% of the admissions to the neonatal intensive care units in both groups resulted from violations in American College of Obstetricians and Gynecologists criteria. CONCLUSION: The overall neonatal intensive care unit admission rate after scheduled cesarean delivery in this study is consistent with that reported in the neonatology literature. Patients of a teaching service were a demographically different group than those on the private service, were less likely to get an elective primary cesarean delivery, and were more likely to be delivered in adherence to American College of Obstetricians and Gynecologists guidelines, although this did not significantly affect the rates of admission to the neonatal intensive care unit or neonatal outcome.

Adolescent↗
PubMed2004

Manual removal or spontaneous placental delivery and postcesarean endometritis and bleeding.

OBJECTIVES: To compare the effect of manual removal and spontaneous delivery of placenta on postcesarean bleeding and endometritis. METHODS: In this prospective study 400 pregnant women undergoing elective cesarean delivery were randomly assigned to two groups: spontaneous placental delivery (200 women) and manual placental delivery (200). No antibiotic prophylaxis was administered in either group. The significance of blood loss due to cesarean delivery was defined by a drop in hemoglobin concentration of more than 1 g/dl 24 h after delivery in comparison with preoperative hemoglobin concentration. Endometritis was diagnosed in patients who developed clinical signs of fever and suprapubic tenderness 48 h after delivery. We analyzed the data using a t-test. RESULTS: The overall endometritis rate was 27%, in 40 women in the spontaneous placental delivery group (20%) and 68 women in the manual placental removal group (34%). There was a statistically significant difference between the two groups (P=0.001). Significant blood loss was experienced by 52 women (26%) in the spontaneous placental delivery group vs. 100 women (50%) in the manual placental delivery group. There was a statistically significant difference in blood loss between the two groups (P=0.000; RR=1.92). CONCLUSION: Endometritis and blood loss in cesarean delivery is increased by manual removal of the placenta compared with the spontaneous method of placental removal.

Adult↗
PubMed1996

Microparticle deposition in periarterial microvasculature and intramural dissections after porous balloon delivery into atherosclerotic vessels: quantitation and localization by confocal scanning laser microscopy.

Local delivery of pharmacologic or genetic agents with a porous balloon catheter offers a potential therapeutic approach to reducing restenosis and atherosclerosis and minimizing undesirable systemic toxicity. However, the delivery efficiency and intramural retention of liquid agents is low. The local intramural delivery and prolonged retention of 5 microns microparticles (MP) has been described previously. The current study was designed to evaluate the distribution of locally delivered MPs and to determine the effects of MP size and infusion pressure on intramural delivery efficiency. A 1% suspension of fluorescent, latex MPs (1 or 4.5 microns in diameter) was infused at either 3 or 6 atm into atherosclerotic rabbit femoral arteries (n = 32) immediately after angioplasty. Four groups of arteries were evaluated: 1) 1 micron MPs infused at 3 atm; 2) 1 micron MPs at 6 atm; 3) 4.5 microns MPs at 3 atm; and 4) 4.5 microns MP at 6 atm. The location of MPs was evaluated by fluorescent and light microscopy and confocal laser scanning microscopy. The tissue was dissolved and the delivered MPs quantified. All groups manifested numerous MPs within the vasa vasorum and periadventitial microvasculature, with a substantially lesser number within the neointimal and medial layers. The intramural deposition of the MPs was associated with dissection within the intima or media caused by the antecedent angioplasty or local delivery, indicating that an intact vessel wall is an anatomic barrier to MP delivery. The median values of fractional intramural delivery, defined as the percentage of infused MPs retained within the arterial wall, were 0.059%, 0.071%, 0.047%, and 0.062% for the groups 1 through 4, respectively (p not significant [NS]). The values of intramural particle concentration, expressed as the total number of MPs per weight of arterial tissue, were 55, 65, 1.5, and 1.2 x 10(4) MPs/mg for groups 1 through 4, respectively (p < 0.001 for 1 micron vs 4.5 microns MPs). Although more 1 microM MPs were delivered than 4.5 microns MPs, the fractional intramural delivery was unaffected by particle size or infusion pressure. The local delivery of MPs at atherosclerotic sites after angioplasty is characterized by fractional intramural delivery values similar to values of nonparticulate agents, with few MPs deposited into intima or media in the absence of a dissection caused by the antecedent angioplasty or the delivery procedure itself.

Angioplasty, Balloon, Coronary↗
PubMed1998

Declining cesarean delivery rates in California: an effect of managed care?

OBJECTIVES: We hypothesized that movement from traditional indemnity insurance to managed care in California between 1983 and 1994 would lead to reductions in the rate of cesarean delivery. STUDY DESIGN: We decomposed the frequency of cesarean delivery with each primary diagnosis into the product of the diagnosis rate among all women and the cesarean delivery rate among women with the given diagnosis (conditional cesarean delivery rate). We used logistic regression to estimate the diagnosis and conditional cesarean delivery rates. RESULTS: Adjusted and observed cesarean delivery rates are indistinguishable. Both the diagnosis rates and the conditional cesarean delivery rates contributed to the increase in the cesarean delivery rate between 1983 and 1987. The subsequent decline is attributable to the decline in the repeated cesarean delivery rate. CONCLUSIONS: The increase in managed care in California played no apparent role in the decline in the cesarean delivery rate. With the exception of Kaiser health maintenance organizations, managed care providers and indemnity insurers managed deliveries similarly.

Adult↗
PubMed1999

Cesarean delivery risk adjustment for regional interhospital comparisons.

OBJECTIVE: The aim of this study was to determine the effect of adjustment for patient population mix on observed, expected, and standardized cesarean delivery rates in regional hospitals. STUDY DESIGN: Multiple logistic regression was applied to a large regional perinatal database comprising 16 hospitals. Variables significantly associated with cesarean delivery were used to calculate cesarean delivery probabilities for individual patients. Probabilities were summed across hospitals to derive expected hospital cesarean delivery rates. A standardized rate for each hospital was then calculated by dividing the observed rate by the expected rate and multiplying by the regional rate. RESULTS: The regional cesarean delivery rate was 21.9% for 6798 women. Observed hospital rates varied from 17.1% to 39.2%. Twenty-two variables were associated with cesarean delivery. Expected cesarean delivery rates ranged from 18.1% to 26.0%. Among the 5 hospitals with the lowest observed cesarean delivery rates only 2 had rates significantly lower than those of the rest of the region, and only 1 of those 2 rates remained significantly lower after adjustment. One other hospital that had an adjusted rate significantly lower than the crude rate had not appeared statistically different from the rest of the region before standardization. Among the 5 hospitals with the highest cesarean delivery rates, 4 had rates significantly higher than the rest of the region, and 3 of them had significantly higher observed rates than expected rates. CONCLUSIONS: Compared with using observed (crude) cesarean delivery rates, adjustment for differences in patient risk factor mix facilitates more accurate comparison of cesarean delivery rates among hospitals within a region.

Adult↗
PubMed1999

Predicting risk of preterm delivery by second-trimester measurement of maternal plasma corticotropin-releasing hormone and alpha-fetoprotein concentrations.

OBJECTIVE: Many women who have preterm labor have abnormally high plasma concentrations of the placental peptide corticotropin-releasing hormone and the fetal product alpha-fetoprotein in early pregnancy. This study was designed to evaluate the ability of these biochemical tests and a clinical risk factor score to prospectively discriminate pregnancies at high risk for preterm delivery. STUDY DESIGN: Eight hundred sixty women were studied prospectively from the early second trimester until delivery. A risk factor score for preterm delivery was calculated from the clinical history and maternal plasma corticotropin-releasing hormone and alpha-fetoprotein concentrations were measured by radioimmunoassay between 17 and 30 weeks' gestation. The risk factor score, corticotropin-releasing hormone concentration, and alpha-fetoprotein concentration for each woman were expressed as individual odds or likelihood ratios for preterm delivery and as a combined risk estimate derived from the 3 tests. RESULTS: Sixty women had preterm deliveries (n = 37 spontaneous labor, n = 23 planned deliveries), and these women had significantly higher concentrations of corticotropin-releasing hormone (median 1.92 multiples of the median) and alpha-fetoprotein (median 1.32 multiples of the median) than did women with term deliveries (median 1.00 multiples of the median, P <.001 for both tests), with these abnormalities being evident from early in the second trimester. The risk factor score was >/=10 in 28% of women with preterm delivery and 7% of women with term delivery. The combination of all 3 markers resulted in a higher detection rate and a higher positive predictive value than the risk factor score, corticotropin-releasing hormone concentration, or alpha-fetoprotein concentration alone, correctly discriminating 37% of women who would have preterm deliveries with a false-positive rate of 5%. The positive predictive value was also 37% (odds of being affected given a positive result were 1:1.7). CONCLUSIONS: The combination of measurement of maternal plasma corticotropin-releasing hormone and alpha-fetoprotein concentrations in the second trimester with risk factor scoring provides a more accurate indicator of the risk of preterm delivery than does risk factor scoring alone. This method of risk assessment may therefore be of use in targeting prevention strategies.

Adolescent↗
PubMed1997

Cervicovaginal washing prolactin assay in prediction of preterm delivery.

OBJECTIVE: Our purpose was to determine the utility of cervicovaginal washing prolactin assay in prediction of preterm birth in women without rupture of membranes. METHODS: Sixty-six women with normal singleton pregnancy were submitted to cervicovaginal washing and serum prolactin assays. The latency period to delivery and gestational age at admission and at delivery were also recorded. According to uterine contractions and obstetrical history regarding the previous preterm delivery, the pregnant women were divided into 4 groups: 18 symptomatic (group 1) and 15 asymptomatic (group 2) pregnancies who had previously had preterm delivery, and 18 symptomatic (group 3) and 15 asymptomatic (group 4) pregnancies without a history of prior preterm delivery were enrolled in the study. RESULTS: The cervicovaginal washing prolactin concentrations were significantly higher in groups 1 and 3 than in group 4 (P < 0.0083). With respect to the latency period to delivery and the birth weeks, groups 2 and 4 were significantly higher than groups 1 and 3 (F < 0.0001). In the evaluation of the whole group, a significant negative correlation was observed both between cervicovaginal washing prolactin concentrations and the lapsed times to delivery, and the gestational ages at delivery. The finding of a cervicovaginal washing prolactin value exceeding 50 ng/ml in the 12 days preceding preterm delivery had sensitivity, specificity, positive and negative predictive values of 65%, 95%, 86%, and 81%, respectively. CONCLUSIONS: A cervicovaginal washing prolactin value more than 50 ng/ml precedes preterm delivery within 12 days at > 29 weeks. The easy application, the good feasibility, the success in identifying pregnancies at risk for preterm labor, and the cost effectiveness suggests cervicovaginal washing prolactin assay as a biochemical marker for preterm delivery.

Adult↗
PubMed2000

Elective induction of labor as a risk factor for cesarean delivery among low-risk women at term.

OBJECTIVE: To determine the effects of elective induction on the risk of cesarean delivery in a cohort of women with low-risk term pregnancies and to evaluate the costs of elective induction services within our hospital system. METHODS: Records of 1135 eligible women with low-risk, singleton, vertex pregnancies at 38-41 weeks' gestation who were eligible for vaginal delivery were analyzed retrospectively after elective induction (n = 263) or spontaneous labor (n = 872). Outcome measures included cesarean delivery and direct costs. Variables evaluated were parity, maternal age, estimated gestational age, birth weight, prior cesarean delivery, epidural anesthetic use, and provider category. Analysis was by univariable and multivariable regression modeling. RESULTS: Elective induction placed nulliparas at a twofold higher risk for cesarean delivery (odds ratio 2.4, 95% confidence interval 1.2, 4.9) after adjustment for birth weight, maternal age, and gestational age. We found a significantly increased risk of cesarean delivery with increased birth weight for nulliparas (2-66.7%). Increasing maternal age increased the risk of cesarean delivery in all parity groups (P <.05), but particularly among nulliparas (3-26.3%) (P <.001). Electively induced labors that ended in vaginal delivery cost $273 more and required an average of 4 hours more in the hospital before delivery than did noninduced vaginal deliveries (P <.001). CONCLUSION: Elective induction significantly increased the risk of cesarean delivery for nulliparas, and increased in-hospital predelivery time and costs.

Adult↗
PubMed2002

Obstetricians' opinions regarding patient choice in cesarean delivery.

OBJECTIVE: To survey the opinions of Israeli obstetricians regarding their position on patient choice cesarean delivery. METHODS: Short anonymous questionnaires were sent by mail. The questionnaire included basic demographic data followed by three short case presentations of patients requesting cesarean delivery without a medical indication; the respondents were asked if they would consent to the patients' request. Respondents were then asked about their personal preferences on the mode of delivery, their attitude towards women's right to choose cesarean delivery, and whether obstetricians should inform their patients of this right. RESULTS: Of the 650 questionnaires sent, 257 were returned. Most of the respondents were specialists, aged 35 years or older, and worked in hospitals. Seventy-five percent were male, and 27% had a teaching academic degree. The consent rate for patient choice cesarean delivery in the three case presentations ranged from 40% to 79%. Only 9% of the respondents said they would prefer cesarean delivery for themselves (if female) or for their partners. Forty-five percent supported women's right to choose cesarean delivery, and half of them stated that obstetricians should inform their patients of this right. CONCLUSION: Although the vast majority (91%) of the Israeli respondents personally prefer vaginal delivery, almost half of them support women's autonomy to choose cesarean delivery. Consequently, approximately 50% of the respondents were willing to perform cesarean delivery on request because of their support of women's autonomy, despite the fact that they believe that vaginal delivery is a better option.

Adult↗
PubMed2003

Predicting term and preterm delivery with transabdominal uterine electromyography.

OBJECTIVE: To determine whether delivery can be predicted using transabdominal uterine electromyography. METHODS: A total of 99 patients were grouped as either term (37 weeks or more) or preterm (less than 37 weeks). Uterine electrical activity was recorded for 30 minutes in clinic. Electromyographic "bursts" were evaluated to determine the power density spectrum. Measurement-to-delivery time was compared with the average power density spectrum's peak frequency. Receiver operating characteristic curve analysis was performed for 48, 24, 12, and 8 hours from term delivery, and 6, 4, 2, and 1 day(s) from preterm delivery. RESULTS: The power density spectrum peak frequency increased as the measurement-to-delivery interval decreased. Receiver operating characteristic curve analysis gave high positive and negative predictive values for both term and preterm delivery. At term, the average power density spectrum peak frequency was significantly higher for the 24-or-fewer-hours-to-delivery group than for the more-than-24-hours-to-delivery group, whereas at preterm, the average power density spectrum peak frequency was significantly higher in the 4-or-fewer-days-to-delivery group than in the more-than-4-days-to-delivery group (P <.05). CONCLUSION: Transabdominal uterine electromyography predicts delivery within 24 hours at term and within 4 days preterm. This methodology offers many advantages and benefits that are not available with present uterine monitoring systems.

Adolescent↗
PubMed1998

Effect of departmental policies on cesarean delivery rates: a community hospital experience.

OBJECTIVE: During 1994, our department adopted several strategies in an attempt to decrease our cesarean delivery rates. This study evaluates the effect of these changes on our cesarean delivery rates. METHODS: We studied data of women who delivered at our community hospital obstetric unit over a period of 6 years, from January 1, 1991, to December 31, 1996. During 1994, our department adopted labor management and cesarean delivery guidelines, with review of every cesarean delivery that did not meet guidelines and confidential individual feedback; established 24-hour in-house coverage; and attempted to achieve the goal of an annual cesarean delivery rate of less than 15%. These data were evaluated by chi2 analysis. Women who delivered in the first 3 years (group A) were compared with those who delivered in the second 3 years (group B) (ie, when the changes occurred). P < .05 was considered significant. RESULTS: Groups A and B shared similar demographic characteristics. The total cesarean delivery rate decreased from 22.5% (group A) to 18.6% (group B) (P = .001), whereas the primary cesarean delivery rate decreased from 13.5% to 10.6% (P = .001) and the repeat cesarean delivery rate decreased from 9.0% to 7.9% (P = .03). The proportion of women who received oxytocin and regional anesthesia and underwent vacuum-assisted deliveries increased (P < .001), whereas perinatal mortality and morbidity did not change. CONCLUSION: The cesarean delivery rate safely decreased. These data suggest the importance of the commitment of attending physicians to a lower cesarean delivery rate, of service improvements, and of detailed feedback.

Adolescent↗
PubMed1997

Rumen-stable delivery systems.

Ruminants have a distinct digestive system which serves a unique symbiotic relationship between the host animal and predominantly anaerobic rumen bacteria and protozoa. Rumen fermentation can be both beneficial by enabling utilization of cellulose and non-protein nitrogen and detrimental by reducing the nutritive value of some carbohydrates, high biological value proteins and by hydrogenating unsaturated lipids. In addition it can also result in the modification and inactivation of many pharmacologically active ingredients administered to the host animal via the oral route. The advances in ruminant nutrition and health demand a rumen-stable delivery system which can deliver the active ingredient post-ruminally while simultaneously meet efficacy, safety and cost criteria. In contrast to drug delivery systems for humans, the demand for low-cost has hindered the development of effective rumen-stable delivery systems. Historically, heat and chemical treatment of feed components, low solubility analogues or lipid-based formulations have been used to achieve some degree of rumen-stability, and products have been developed accordingly. Recently, a polymeric pH-dependent rumen-stable delivery system has been developed and commercialized. The rationale of this delivery system is based on the pH difference between ruminal and abomasal fluids. The delivery system is composed of a basic polymer, a hydrophobic substance and a pigment material. It can be applied as a coating to solid particles via a common encapsulation method such as air-suspension coating. In the future, the delivery system could be used to deliver micronutrients and pharmaceuticals post-ruminally to ruminant animals. A further possible application of the delivery system is that it could also be combined with other controlled delivery devices/systems in order to enhance slow release or to achieve targeted delivery needs for ruminants. This paper discusses the rumen protection and the abomasal release mechanism of the polymeric coating. It also reviews other rumen stable delivery systems and methods for evaluating their in vitro and in vivo performance.

Journal Article↗
PubMed2005

Cord gas analysis, decision-to-delivery interval, and the 30-minute rule for emergency cesareans.

OBJECTIVE: Our primary objective was to examine the relationship between umbilical arterial gas analysis and decision-to-delivery interval for emergency cesareans performed for nonreassuring fetal status to determine if this would validate the 30-minute rule. STUDY DESIGN: For this retrospective cohort study, all cesarean deliveries performed for nonreassuring fetal status from September 2001 to January 2003 were reviewed. A synopsis of clinical information that would have been available to the clinician at the time of delivery and the last hour of the electronic fetal heart rate tracing prior to delivery were reviewed by three different maternal-fetal medicine specialists masked to outcome, who classified each delivery as either emergent (delivery as soon as possible) or urgent (willing to wait up to 30 minutes for delivery) since immediacy of the fetal condition is the key factor affecting the type of anesthesia used. RESULTS: Of 145 cesareans performed for nonreassuring fetal status during this period, 117 patients met criteria for entry, of which 34 were classified as emergent and 83 as urgent. Kappa correlation was 0.35, showing only fair/moderate agreement between reviewers. In the emergent group, general anesthesia was more common (35.3%, 10.8%, p=0.003), and the decision-to-delivery interval was 14 minutes shorter (23.0+/-15.3, 36.7+/-14.9 minutes, p<0.001). Linear regression showed a statistically significant relationship between increasing decision-to-delivery interval and umbilical arterial pH (r=0.22, p=0.02) and base excess (r=0.33, p<0.001) showing that delivery proceeded sooner for most of those with the worst cord gases, with a gradual improvement over time. For the 13 (11%) neonates with cord gases placing them at increased risk for long-term neurologic sequelae, the decision-to-delivery interval was 24.7+/-14.6 minutes (range 6 to 50 minutes), and 3/13 (23%) were classified as urgent rather than emergent. CONCLUSION: Electronic fetal monitoring shows considerable variation in interpretation among maternal-fetal medicine specialists and is not a sensitive predictor of the fetus developing metabolic acidosis. There is no deterioration in cord gas results after 30 minutes, and most neonates delivered emergently or urgently for nonreassuring fetal status even when born after 30 minutes have normal cord gases. The 30-minute rule is a compromise that reflects the time it takes the fetus to develop severe metabolic acidosis, our imprecision in its identification, and its rarity in the presence of nonreassuring fetal monitoring.

Acidosis↗
PubMed2006

Cesarean delivery: background, trends, and epidemiology.

OBJECTIVE: To examine trends in cesarean delivery for the overall population and for women with "no indicated risk" for cesarean section, and to summarize the available literature on "maternal request" cesarean deliveries. FINDINGS: Nearly 3 in 10 births were delivered by cesarean section in 2004 (29.1%), the highest rate ever reported in the United States. The overall rate has increased by over 40% since 1996, reflecting two concurrent trends: an increase in the primary rate (14.6% to 20.6%), and a steep decline in the rate of vaginal birth after cesarean (28.3% to 9.2%). There has been a clear increase in primary cesarean delivery without a medical or obstetrical indication, and studies using hospital discharge data or birth certificate data estimate the rate of primary cesarean deliveries with no reported medical or obstetrical indication to be between 3% and 7% of all deliveries to women who had not had a previous cesarean delivery. However, these studies contain no direct information on whether these cesareans were the result of maternal request or because of physician recommendation. There was little data to support the contention that the rise in the cesarean rate was the result of maternal request. CONCLUSION: There are no systematic data available on cesarean delivery by "maternal request." However, the rate of primary cesarean delivery is increasing rapidly for women of all ages, races, and medical conditions, as well as for births at all gestational ages. Since a first cesarean section virtually guarantees that subsequent pregnancies will be cesarean deliveries (the repeat cesarean delivery rate is now almost 91%), research is needed on physician practice patterns, maternal attitudes, clinical outcomes for mother and infant (harms, benefits), and clinical and nonclinical factors (institutional, legal, economic) that affect the decision to have a cesarean delivery.

Age Factors↗
PubMed1996

Conflicts between physicians and patients in non-elective cesarean delivery: incidence and the adequacy of informed consent.

A study was undertaken in 372 consecutive patients undergoing non-elective cesarean delivery to explore the incidence and nature of conflicts between physician and patient surrounding the decision to undergo non-elective cesarean delivery; to examine the adequacy of informed consent at the time of non-elective cesarean delivery; and to describe the importance of a preventive ethics approach to non-elective cesarean delivery. During a 6-month interval, all patients who underwent non-elective cesarean delivery and their physicians were asked to take part in a survey in the early postpartum period concerning their response to recommendations for cesarean delivery. The survey included demographics as well as questions pertaining to informed consent and the presence and nature of patient-physician conflict. Of the 326 patients who were interviewed, 319 (98%) agreed to the recommendation for non-elective cesarean delivery and 7 patients (2%) initially disagreed. Reasons for disagreeing included: feared surgery (4 of 7), needed husband's approval (1 of 7), and questioned the medical necessity of surgery (2 of 7). In all 7 cases of initial disagreement, cesarean delivery was eventually performed with the patient's consent. The mean age of patients who initially disagreed was younger (24.7 +/- 6) than that of those who agreed (31.0 +/- 4 [p < 0.05]). Conflicts were present in 7 of 113 clinic patients and 0 of 213 private patients (p < 0.05). Of those surveyed, 26 (8.7%) indicated that they did not have adequate input in the decision for non-elective cesarean delivery. Patients with inadequate input expressed significantly more concerns with regard to the effect of surgery on their own health (p < 0.05) as well as its effect on the baby (p < 0.05). Our findings suggest that even though the incidence of physician-patient conflict about non-elective cesarean delivery was quite low, a significant number of patients (1 in 12) may have reservations concerning the informed consent process at the time of non-elective cesarean delivery. Patients with reservations are more likely to have greater concerns with regard to maternal and fetal risks, suggesting that a more detailed risk disclosure prior to the procedure is warranted for all pregnant patients. Perhaps by incorporating the preventive strategies discussed, the adequacy of informed consent and therefore the patient's autonomy could be enhanced, thus diminishing patient reservations and preventing physician-patient conflict in the intrapartum period.

Adult↗