oxytocin and Shock

Topics: Animals; Cattle; Endocrine Glands; Humans; Hypotension; Hypothalamus; Neurophysins; Oxytocin; Rats; Shock; Stress, Physiological; Vasopressins

Topics: Adrenal Glands; Adrenocorticotropic Hormone; Animals; Arginine Vasopressin; beta-Endorphin; Circadian Rhythm; Dynorphins; Endocrine Glands; Endorphins; Enkephalins; Female; Humans; Hypothalamo-Hypophyseal System; Islets of Langerhans; Melanocyte-Stimulating Hormones; Oxytocin; Pain; Pituitary Gland, Anterior; Pituitary Gland, Posterior; Pregnancy; Rats; Receptors, Opioid; Shock; Stress, Physiological

Topics: Angiotensin II; Animals; Aorta; Arterioles; Blood Pressure; Catecholamines; Diabetes Insipidus; Female; Homeostasis; Male; Microcirculation; Mononuclear Phagocyte System; Muscle Contraction; Muscle, Smooth, Vascular; Oxytocin; Phagocytosis; Rats; Rats, Brattleboro; Rats, Inbred Strains; Rats, Mutant Strains; Shock; Vasopressins; Wounds and Injuries

Postpartum hemorrhage (PPH) is an important cause of maternal mortality (MM) around the world. Seventy percent of the PPH corresponds to uterine atony. The objective of our study was to evaluate multicenter PPH cases during a 10-month period, and evaluate severe postpartum hemorrhage management.. The study population is a cohort of vaginal delivery and cesarean section patients with severe postpartum hemorrhage secondary to uterine atony. The study was designed as a descriptive, prospective, longitudinal, and multicenter study, during 10 months in 13 teaching hospitals.. Total live births during the study period were 124,019 with 218 patients (0.17%) with severe postpartum hemorrhage (SPHH). Total maternal deaths were 8, for mortality rate of 3.6% and a MM rate of 6.45/100,000 live births (LB). Maternal deaths were associated with inadequate transfusion therapy.. In all patients with severe hemorrhage and subsequent hypovolemic shock, the most important therapy is intravascular volume resuscitation, to reduce the possibility of target organ damage and death. Similarly, the current proposals of transfusion therapy in severe or massive hemorrhage point to early transfusion of blood products and use of fresh frozen plasma, in addition to packed red blood cells, to prevent maternal deaths.

Topics: Adolescent; Adult; Blood Component Transfusion; Central America; Cesarean Section; Cohort Studies; Delivery, Obstetric; Erythrocyte Transfusion; Female; Humans; Ligation; Longitudinal Studies; Methylergonovine; Oxytocics; Oxytocin; Postpartum Hemorrhage; Pregnancy; Prospective Studies; Prostaglandins; Severity of Illness Index; Shock; Suture Techniques; Uterine Artery; Uterine Artery Embolization; Uterine Balloon Tamponade; Uterine Inertia; Young Adult

Estrogen receptors are located in important brain areas that integrate cardiovascular and hydroelectrolytic responses, including the subfornical organ (SFO) and supraoptic (SON) and paraventricular (PVN) nuclei. The aim of this study was to evaluate the influence of estradiol on cardiovascular and neuroendocrine changes induced by hemorrhagic shock in ovariectomized rats. Female Wistar rats (220-280 g) were ovariectomized and treated for 7 days with vehicle or estradiol cypionate (EC, 10 or 40 μg/kg, sc). On the 8th day, animals were subjected to hemorrhage (1.5 ml/100 g for 1 min). Hemorrhage induced acute hypotension and bradycardia in the ovariectomized-oil group, but EC treatment inhibited these responses. We observed increases in plasma angiotensin II concentrations and decreases in plasma atrial natriuretic peptide levels after hemorrhage; EC treatment produced no effects on these responses. There were also increases in plasma vasopressin (AVP), oxytocin (OT), and prolactin levels after the induction of hemorrhage in all groups, and these responses were potentiated by EC administration. SFO neurons and parvocellular and magnocellular AVP and OT neurons in the PVN and SON were activated by hemorrhagic shock. EC treatment enhanced the activation of SFO neurons and AVP and OT magnocellular neurons in the PVN and SON and AVP neurons in the medial parvocellular region of the PVN. These results suggest that estradiol modulates the cardiovascular responses induced by hemorrhage, and this effect is likely mediated by an enhancement of AVP and OT neuron activity in the SON and PVN.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiovascular System; Estradiol; Female; Hypothalamus; Models, Animal; Neurons; Ovariectomy; Oxytocin; Paraventricular Hypothalamic Nucleus; Prolactin; Rats; Rats, Wistar; Shock; Supraoptic Nucleus; Vasopressins

Pre-eclampsia is a serious obstetric complication associated with a high rate of maternal and fetal morbidity and mortality. We report the case of a woman with a medical history of insulin-dependent diabetes mellitus and seizures possibly related to hypoglycemia who was admitted for an emergency cesarian due to severe pre-eclampsia and macrosomic fetus. In the first hour after delivery she experienced loss of consciousness and seizure, with vaginal bleeding and hypovolemic shock. Maximum vigilance is required for a patient with several concomitant diseases and a high-risk pregnancy. All prophylactic measures to lower the risk to mother and fetus should be undertaken. We analyze preanesthetic assessment, differential diagnosis, and choice of anesthesia in relation to this case.

Topics: Adult; Cesarean Section; Diabetes Mellitus, Type 1; Diagnosis, Differential; Embolism, Amniotic Fluid; Emergencies; Epilepsy; Female; Fetal Macrosomia; Humans; Hypoglycemia; Hysterectomy; Infant, Newborn; Oxytocin; Postoperative Complications; Pre-Eclampsia; Pregnancy; Pregnancy Complications; Pregnancy in Diabetics; Pregnancy, High-Risk; Puerperal Disorders; Shock; Stroke; Uterine Hemorrhage

Topics: Ergonovine; Extraction, Obstetrical; Female; Humans; Labor Stage, Third; Nurse Midwives; Obstetric Nursing; Oxytocics; Oxytocin; Pregnancy; Pregnancy Complications; Shock; Uterine Inversion

Adrenocorticotropic hormone (ACTH) secretion from the anterior pituitary is predominantly regulated by corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) synthesized in neurons of the paraventricular nucleus (PVN) of the hypothalamus. Secretion of ACTH occurs in pulsatile bursts. To explore the relationship between hypothalamic control and the pulsatile pattern of ACTH secretion, we measured ACTH in 2 min blood samples over 4 h in rats with intact and lesioned PVN during hypovolemic-stress or control conditions and also measured median eminence (ME) levels of CRH, AVP, and oxytocin (OT). Mean plasma ACTH was highest in the sham lesioned-hypovolemic group, lowest in the sham lesioned-control group and intermediate in the two PVN-lesioned groups. CRH in the ME was negligible in the lesioned animals and correlated with OT and AVP. Pulsatile secretion was observed despite PVN ablation. Visual inspection of composite time series suggested different temporal patterns of ACTH secretion. Principal components analysis of the individual ACTH time series revealed three significant eigenvectors which correlated differentially with the three treatment groups. Neither lesioned group had the steep rise over 10 min seen in plasma ACTH in the non-lesioned groups. Delayed ACTH rise after 30-60 min occurred in all but the sham control group. Our data suggest that CRH is responsible for immediate secretion of ACTH in response to hypovolemic stress and that regulators from non-PVN sites may be responsible for more delayed secretion of ACTH in this setting. The persistence of ME AVP and OT levels in the face of > 90% reduction in ME CRH levels leaves open the question of a role for one or both of these peptides in the delayed ACTH response following stress onset and in the generation of pulsatile ACTH secretory bursts.

Topics: Adrenocorticotropic Hormone; Animals; Arginine Vasopressin; Corticotropin-Releasing Hormone; Hypothalamic Hormones; Male; Median Eminence; Oxytocin; Paraventricular Hypothalamic Nucleus; Rats; Rats, Sprague-Dawley; Secretory Rate; Shock

The aim of this paper is to determine the antecedent factors, clinical presentation, complications and management of uterine rupture in the context of modern obstetric practice in Singapore. We conducted a retrospective study of 26 proven cases of uterine rupture in Kandang Kerbau Hospital, Singapore between January 1983 to December 1992. These cases were analysed with regards to their past history, clinical presentation, complications, management and outcome. The incidence of uterine rupture was 1 in 6331 deliveries. The ratio of cases with scarred uteri against those with unscarred uteri was 3:1. The commonest antecedent factor was previous lower segment caesarean section for the scarred group and cephalo-pelvic disproportion in the unscarred group. Overall, 46.2% of the patients had augmentation with oxytocin. The major clinical presentations were abnormal cardiotocogram (25%) and blood-stained amniotic fluid (20%) in the scarred group, and postpartum haemorrhage (50%) and shock (33%) in the unscarred group. Repair of the uterus with or without tubal ligation was performed in 95% of the patients with scarred uteri, whereas 67% of the patients with unscarred uteri underwent total abdominal hysterectomy with or without salpingo-oophorectomy. There was 1 (3.8%) maternal death. Maternal morbidity included bladder injuries, broad ligament haematoma, disseminated intravascular coagulation and gastrointestinal bleeding. The overall incidence of fetal loss was 7.4%. When compared to a previous study on uterine rupture in the same hospital, there was an improvement in obstetric performance.

Topics: Adult; Amniotic Fluid; Blood; Cardiotocography; Cesarean Section; Cicatrix; Delivery, Obstetric; Fallopian Tubes; Female; Fetal Death; Humans; Hysterectomy; Incidence; Infant, Newborn; Maternal Mortality; Obstetric Labor Complications; Ovariectomy; Oxytocin; Postpartum Hemorrhage; Pregnancy; Retrospective Studies; Shock; Singapore; Sterilization, Tubal; Treatment Outcome; Uterine Diseases; Uterine Rupture

The present investigations determined the effects of dietary sodium deprivation on the neurohypophysial secretion of arginine vasopressin (AVP) and oxytocin (OT) by rats in response to nonhypotensive hypovolemia induced by subcutaneous injection of 30% polyethylene glycol solution. In rats fed either standard sodium-rich laboratory chow or sodium-deficient diet for 8 days, AVP secretion increased gradually in proportion to plasma volume deficits up to 22-28% while pituitary secretion of OT was not stimulated. However, when hypovolemia was more pronounced, secretion of both hormones was marked in rats fed standard chow, whereas rats fed sodium-deficient diet were significantly less responsive. These effects did not reflect a general insensitivity of the neurohypophysial system because sodium-deprived and chow-fed rats secreted AVP and OT equivalently in response to intravenous infusion of 1.5 M NaCl solution. Nor did they reflect a general insensitivity to hypovolemia because sodium-deprived rats drank substantial, above-normal volumes of water after colloid treatment. Instead, the results appear to reflect a specific inhibition of stimulatory baroreceptor inputs to AVP and OT neurons during dietary sodium deprivation in rats.

Topics: Animals; Arginine Vasopressin; Blood Proteins; Drinking Behavior; Homeostasis; Infusions, Intravenous; Male; Oxytocin; Pituitary Gland; Polyethylene Glycols; Rats; Rats, Sprague-Dawley; Shock; Sodium; Sodium Chloride; Sodium, Dietary

Interactions between emotional stress due to fear and hypovolemic stimuli on vasopressin secretion were studied in rats. Intraperitoneally injected dextran did not significantly change plasma osmolality and arterial blood pressure but increased blood hemoglobin and plasma vasopressin level. An i.v. infused physiological solution reversed these changes. Emotional stress due to fear acquired by learning suppressed plasma vasopressin level in dextran-injected rats. Emotional stress due to fear produced by low-frequency footshocks also suppressed the increased plasma vasopressin level. These results suggest that emotional stress due to fear interacts with afferent neural signals originating from cardio-vascular volume receptors in the control of vasopressin secretion.

Topics: Animals; Blood Pressure; Dextrans; Electroshock; Fear; Learning; Male; Oxytocin; Rats; Rats, Inbred Strains; Shock; Stress, Psychological; Vasopressins

A retrospective review identified 56 patients with uterine inversion, from July 1977 through June 1986, from weekly obstetric statistics, delivery records and computerized discharge diagnoses. All patients underwent delivery by house officers, midwives or medical students under supervision. An analysis of the data revealed that the risk factors were primiparity, a fundally implanted placenta and delivery of a macrosomic fetus. Also, patients who received oxytocin with or without MgSO4 were at higher risk of puerperal inversion. MgSO4 by itself did not appear to be a risk factor. A placenta attached at the time of inversion appeared to have a protective effect against the development of shock. The use of betamimetics or MgSO4 appeared to be an acceptable alternative to general anesthesia in relaxing the uterus and aiding in its repositioning. Those agents were more likely to be successful in acute cases than in subacute ones and in second-degree inversion than in third-degree.

Topics: Adolescent; Adult; Anesthesia, General; Birth Weight; Blood Transfusion; Female; Humans; Los Angeles; Magnesium Sulfate; Oxytocin; Parity; Placenta Diseases; Pregnancy; Puerperal Disorders; Retrospective Studies; Risk Factors; Shock; Terbutaline; Uterine Diseases

The relative dependence or independence of the secretion of the neurohypophysial hormones, arginine vasopressin and oxytocin, was investigated using a wide variety of stimuli reported to cause the secretion of one or the other hormone. Differences in species, animal preparations, sampling techniques, assays, and other factors make comparison of many previous studies difficult. The aim of this study was to overcome these problems by using the same methodology, animal species, and assays to compare vasopressin and oxytocin release. To further strengthen the analysis, determinations of vasopressin and oxytocin were done in the same blood samples. The results demonstrated that during simultaneous release of both hormones, vasopressin is released in greater proportion following restraint stress, hemorrhage, isotonic hypovolemia, and nicotine, whereas oxytocin is released in greater proportion following endotoxin or hypertonic saline. Vasopressin was released without oxytocin following diethylstilbestrol. Oxytocin was released without concomitant vasopressin release following exercise, hypothermia, hyperthermia, labour, and lactation. Neither oxytocin nor vasopressin release was observed following thyroid-releasing hormone or insulin-induced hypoglycemia. These data illustrate the marked flexibility of the hypothalamo-neurohypophysial system that regulates secretion of vasopressin and oxytocin.

Topics: Animals; Arginine Vasopressin; Endotoxins; Female; Hemorrhage; Hypothalamo-Hypophyseal System; Male; Oxytocin; Pregnancy; Rats; Rats, Inbred Strains; Saline Solution, Hypertonic; Shock; Stress, Physiological

Subcutaneous injection of polyethylene glycol (PEG) solution in rats produces exponential increases in secretion of arginine vasopressin (AVP) and oxytocin (OT) in proportion to the induced plasma volume deficits. Previously, we reported that acute water loads eliminated the neurohypophyseal hormone responses to hypovolemia, whereas hypertonic NaCl potentiated them. The present experiments indicated that AVP and OT secretion after PEG treatment were blunted by prior maintenance of rats on a sodium-deficient diet for 2 days. In contrast, plasma AVP and OT levels after PEG treatment were enhanced by prior adrenalectomy or ligation of the inferior vena cava or by concurrent administration of phentolamine in association with arterial hypotension. AVP and OT responses to hypovolemia were similarly potentiated in rats made uremic by bilateral nephrectomy or by puncturing their bladders. These results parallel previous findings that osmotic dilution and sodium deprivation each enhance the sodium appetite induced by PEG treatment in rats, whereas hyperosmolality, hypotension, and uremia each abolish it. Consequently, they support our previous hypothesis that sodium appetite is inversely related to the activity of hypothalamic oxytocinergic neurons.

Topics: Adrenalectomy; Animals; Appetite; Arginine Vasopressin; Blood Proteins; Blood Volume; Ligation; Male; Oxytocin; Polyethylene Glycols; Rats; Rats, Inbred Strains; Shock; Sodium; Uremia; Vena Cava, Inferior

Topics: Aprotinin; Blood Coagulation Disorders; Cesarean Section; Cyanosis; Embolism, Amniotic Fluid; Female; Fibrinogen; Humans; Hypotension; Infusions, Parenteral; Oxytocin; Plasminogen; Polyhydramnios; Posture; Pregnancy; Pregnancy Complications, Cardiovascular; Shock; Syndrome; Uterine Hemorrhage; Vena Cava, Inferior

Topics: Female; Halothane; Hypotension; Nephritis; Oxytocin; Pregnancy; Pregnancy Complications; Pregnancy Complications, Infectious; Shock; Surgical Procedures, Operative; Toxicology

Topics: Amniotic Fluid; Female; Humans; Labor, Induced; Labor, Obstetric; Oxytocin; Pathology; Postpartum Hemorrhage; Postpartum Period; Pre-Eclampsia; Pregnancy; Shock; Shock, Hemorrhagic

Topics: Abortion, Septic; Chloramphenicol; Female; Humans; Hydrocortisone; Metaraminol; Norepinephrine; Oxygen Inhalation Therapy; Oxytocin; Penicillins; Phenylephrine; Pregnancy; Sepsis; Shock; Shock, Septic; Streptomycin; Water-Electrolyte Balance