Cervical sonography in preterm labor.

OBJECTIVE: To improve the accuracy of the diagnosis of preterm labor by comparing transvaginal sonography to digital examination of the cervix. METHODS: We performed transvaginal sonography in women with preterm labor who had completed a course of parenteral tocolysis. Cervical length was measured according to criteria reported previously. Cervical sonographic findings were not used in diagnosis or management. Sonographic cervical length was compared to digital assessment of dilation and effacement to assess the risk of preterm birth after treatment for preterm labor. RESULTS: Forty-eight singleton and 12 twin gestations were studied. Thirty women were nulliparous and 30 were parous. The mean (+/- standard deviation) gestational age was 31.1 +/- 2.7 weeks (range 24-35) at the examination and 35.6 +/- 2.9 weeks (range 26-43) at delivery. Twenty-four subjects delivered before 36 weeks' gestation and 36 delivered at or after 36 weeks. Cervical sonography was distinctly superior to digital assessment of dilation and effacement as a test for delivery before 36 weeks, when compared using receiver operating characteristic curves. This analysis indicated a cervical length of 30 mm as the best cutoff to maximize sensitivity and specificity. All 24 subjects who delivered preterm had cervical lengths less than 30 mm. Cervical sonography was especially useful in selecting women with preterm labor who would not deliver prematurely, ie, a high negative predictive value. None of 15 women whose cervical length was 30 mm or more delivered spontaneously before 36 weeks. CONCLUSION. Among women treated for preterm labor, a cervical length of at least 30 mm predicted a low likelihood of preterm birth. Cervical sonography may improve the accuracy of diagnosis in women treated for preterm labor.

History of CPR and the role of the national conference.

External defibrillation was first reported in 1956, mouth-to-mouth ventilation was first reported in 1958, and closed-chest compression in 1960. While these developments began the modern era of CPR, accounts of resuscitative efforts go back to ancient times. The guidelines for CPR and emergency cardiac care (ECC) have evolved through five national conferences, held in 1966, 1973, 1979, 1985, and most recently in February 1992. The purpose of these conferences was to review and update published materials in the light of scientific advances and clinical experience. This issue of the Annals of Emergency Medicine contains the proceedings of the most recent National Conference on CPR and ECC. At this conference, a consensus was reached by an international gathering of scientists and clinicians for guidelines on adult basic and advanced life support, as well as on pediatric and neonatal life support.

Development and initial experience with a manually controlled spring wire device ("Cordostat") to aid in difficult funipuncture.

Funipuncture has evolved as a useful tool in prenatal diagnosis and treatment. The ease with which it can be performed depends on placental implantation site, amniotic fluid volume, fetal presentation and activity, gestational age, and operator experience. Under select circumstances, such as hydramnios, oligohydramnios/anhydramnios, a back-up fetus/posterior placenta, or gestation of fewer than 20 weeks, funipuncture can be difficult or impossible. We have developed a new instrument, the "Cordostat," which can help the operator perform difficult funipuncture by providing stabilization and allowing intrauterine manipulation of the umbilical cord. The instrument consists of a deflecting wire guide threaded through a 19.5-guage trochar needle, which can be manually controlled to coil around and stabilize a free loop of cord. Conventional funipuncture can then be performed through a second uterine puncture. We describe use of this instrument in 12 patients undergoing second-trimester induced abortion.

Traumatic intracardiac communication: detection by color flow mapping.

A previously healthy 20-year-old man underwent emergency surgery for repair of a right ventricular free wall laceration that was the result of a knife wound. A systolic murmur was first heard 1 month later, and two-dimensional echocardiography and color flow mapping demonstrated a communication between the left and right ventricle in the region of the membranous septum. The visualized turbulent flow was consistent with a ventriculoseptal defect but also appeared to extend posteriorly into the left atrium in a direct line with the septal communication. At cardiac catheterization the calculated left-to-right shunt was 1.2:1.

Noninvasive evaluation of cardiac risk before elective vascular surgery.

The prognostic utility for predicting cardiac events was determined for dipyridamole-thallium scintigraphy, exercise stress testing (when possible; n = 69) and multiple clinical variables in 100 consecutive patients admitted for elective surgical repair of peripheral vascular disease. After initial noninvasive evaluation, 11 patients were referred for coronary angiography and the remaining 89 patients had surgery without further cardiac studies. Fifteen patients (17%) had a postoperative myocardial infarction, one of which was fatal. Of these 15 patients, 14 had thallium redistribution and 3 had positive ST segment depression during stress testing. Among the many variables tested, the presence of redistribution on serial dipyridamole-thallium images was the most significant predictor of serious cardiac events. All 11 patients who had coronary angiography had both redistribution and multivessel coronary artery disease. Four of these 11 patients died during follow-up and 6 had coronary artery bypass surgery. It is concluded that dipyridamole-thallium imaging has significant prognostic utility in predicting postoperative myocardial infarction and death in patients with severe peripheral vascular disease, and is superior to exercise testing or clinical variables in determining cardiac risk. The odds for a serious cardiac event were 23 times greater in a patient with thallium redistribution than in a patient without redistribution, strongly suggesting that myocardial imaging may be used as a primary screening test before elective vascular surgery.

Cardiovascular pharmacology. III: Atropine, calcium, calcium blockers, and beta-blockers.

Atropine, calcium, calcium-channel blockers, beta-adrenergic-receptor blockers, oxygen, morphine, vasodilators, and potent diuretics are frequently used in advanced cardiac life support (ACLS). Since the last AHA conference on ACLS standards, little controversy has arisen regarding the use of oxygen, morphine, vasodilators, or potent diuretics. In 1979, a full vagolytic dose of atropine was recommended for use early in the course of asystolic or bradycardiac arrest. Since then reports suggest that this higher dose of atropine may be of some limited value in treating this highly resistant form of arrest. The routine use of calcium for asystole, bradycardiac arrest, and electromechanical dissociation has come under intense scrutiny. Studies have failed to demonstrate improved survival and have found potentially deleterious levels of serum calcium when calcium was administered according to AHA standards. It is also possible that postanoxic cerebral injury is exacerbated by the use of calcium. No controversy exists, however, concerning the use of calcium for the moribund patient with possible hypocalcemia or with an excess of calcium-channel blockers. The use of calcium-channel blockers has been advocated to prevent or retard the intracellular accumulation of calcium, which may cause irreversible postanoxic tissue damage. Calcium-channel blockers may also be useful in preventing or decreasing cerebral and coronary arteriospasm. These drugs have antianginal properties that may decrease ischemia. The antiarrhythmic effect of verapamil is particularly useful in the treatment of uncomplicated paroxysmal supraventricular tachycardia. Verapamil and diltiazem slow conduction through the atrioventricular node and may be used to slow the ventricular response in atrial fibrillation and flutter.(ABSTRACT TRUNCATED AT 250 WORDS)

External compression without adjuncts.

Over the past decade many exciting and promising new approaches of delivering CPR have been studied. Considerable data have accumulated suggesting that forward flow during CPR is generated, at least in part, by the development of elevated intrathoracic pressure with an extrathoracic arteriovenous pressure difference. This mechanism, known as the "thoracic pump," has been documented during "cough-CPR" and has led to numerous attempts at optimizing the outcome by increasing intrathoracic pressure in CPR. Studies have demonstrated improved flows with simultaneous ventilation and sternal compression, with static or interposed abdominal compression, with longer duration compression, and with various combinations of these maneuvers. Other recent studies have suggested that the cardiac compression mechanism may indeed be operative, at least under certain circumstances, and that CPR may be optimized by increasing the force and rate of compression. Still others have advocated a simple change in the sequence of initiating ventilation and compression. Which, if any, of these newly advocated methods improve the outcome when applied to man remains to be established. If any of these techniques is shown to be more advantageous, its widespead use will depend on its applicability without adjuncts and its teachability to the lay public.

Effects of the cessation of training on left ventricular function in the racing greyhound. Serial studies in a model of cardiac hypertrophy.

Exercise-induced cardiac hypertrophy has been associated with normal resting left ventricular function and, after cessation of training, variable degrees of regression. The racing greyhound is an animal with cardiac hypertrophy said to be part congenital and part exercise-induced. Racing greyhounds underwent serial cardiac catheterization three times during an 8-month period after cessation of racing/training to determine the functional consequences of the cessation of training. At the end of 8 months of inactivity the animals' hearts were excised and weighed in order to compare heart weight/body weight (HW/BW) ratios with those obtained in a group of racing greyhounds killed within one month, 19 +/- 16 days (mean +/- SD), of the cessation of training. Comparison of HW/BW ratios failed to reveal a significant difference between the serially studied group, 12.1 +/- 1.9 g/kg (mean +/- SD), and the more recently exercising group, 12.7 +/- 1.4 g/kg (mean +/- SD) of dogs. After 2 months of inactivity, 9 of 12 greyhounds in the serially studied group showed increases in max dP/dt and dP/dt normalized to a pressure of 50 mmHg. Modified pre-ejection period and peak negative dP/dt also increased significantly (p less than .004) during this same period. No further changes in these variables were found at the final 8-month study. Our failure to demonstrate a difference in HW/BW ratios between these two groups of dogs suggests that the exercise-induced component of cardiac hypertrophy in the trained racing greyhound is probably very small and, if it exists, regresses very early (less than 1 month). Changes in contractility indices that were observed occurred after this time period (between 1 and 2 months) and are therefore probably not due to regression of cardiac hypertrophy.