Hemorrhagic shock with paradoxical bradycardia.
TL;DR: The preliminary results of the antishock trouser in this setting are encouraging and the treatment of bradycardia per se may be deleterious and atropine must be avoided in conscious patients with hemorrhagic shock and paradoxical bradyCardia.
Abstract: Two hundred and seventy-three acute hemorrhagic shocks were treated in 1984 in a pre-hospital emergency care unit. Twenty patients (7%) had a paradoxical bradycardia: they were conscious, 9 of them had an undetectable systolic arterial pressure with the sphygmomanometric method but the femoral pulse was still present. All of them recovered from bradycardia with fluid loading alone. The comparison between patients with paradoxical bradycardia and those with tachycardia showed that the former had more severe and rapid hemorrhages. During 1985, 7 new cases of acute hemorrhagic shock with paradoxical bradycardia were treated with an antishock trouser. These patients recovered from bradycardia more quickly (p less than 0.01) and with a less important fluid loading (p less than 0.01) than those previously treated without the antishock trouser. Two other patients were treated with atropine before antishock trouser inflation and experienced ventricular premature beats and one developed ventricular fibrillation. A paradoxical bradycardia can occur in hemorrhagic shock and denotes a rapid and severe hemorrhage requiring a massive and rapid fluid loading. The preliminary results of the antishock trouser in this setting are encouraging. The treatment of bradycardia per se may be deleterious and atropine must be avoided in conscious patients with hemorrhagic shock and paradoxical bradycardia.
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TL;DR: Reflex cardiovascular depression with vasodilation and bradycardia has been variously termed vasovagal syncope, the Bezold-Jarisch reflex and neurocardiogenic syncope; Epinephrine must be used early in established cardiac arrest, especially after high regional anaesthesia.
Abstract: Reflex cardiovascular depression with vasodilation and bradycardia has been variously termed vasovagal syncope, the Bezold–Jarisch reflex and neurocardiogenic syncope. The circulatory response changes from the normal maintenance of arterial pressure, to parasympathetic activation and sympathetic inhibition, causing hypotension. This change is triggered by reduced cardiac venous return as well as through affective mechanisms such as pain or fear. It is probably mediated in part via afferent nerves from the heart, but also by various non-cardiac baroreceptors which may become paradoxically active. This response may occur during regional anaesthesia, haemorrhage or supine inferior vena cava compression in pregnancy; these factors are additive when combined. In these circumstances hypotension may be more severe than that caused by bradycardia alone, because of unappreciated vasodilation. Treatment includes the restoration of venous return and correction of absolute blood volume deficits. Ephedrine is the most logical choice of single drug to correct the changes because of its combined action on the heart and peripheral blood vessels. Epinephrine must be used early in established cardiac arrest, especially after high regional anaesthesia.
303 citations
TL;DR: The administration of isoproterenol during a passive upright tilt may identify persons who suffer from or are prone to a vasodepressor reaction, and Beta-adrenergic receptor blockade with propranolol inhibited all aspects of the isoprotserenol-induced faint.
Abstract: The ability of isoproterenol to induce symptoms and laboratory findings of a vasodepressor reaction was tested in 48 patients, ages 17 to 74, divided into 4 groups according to the reason for their referral. Group 1 comprised 12 patients with vasodepressor syncope, group 2 had 8 patients with syncope of unknown origin, group 3 included 11 patients with syncope due to seizures in 2 and ventricular tachycardia in 9, group 4 had 17 patients with various arrhythmias not associated with syncope. Isoproterenol boluses were administered starting at 2 μg and increased in 2-μg steps to a maximum of 8 μg at 0 ° and +60 °. The responses at 0 ° were all normal. At +60 ° a vasodepressor reaction consisting of syncope or near syncope, hypotension and bradycardia was produced by isoproterenol (mean dose 6.0 ± 0.26 μg) in 8 patients from group 1 (66.6%), 4 from group 2 (50%), 0 from group 3 and 4 from group 4 (23.5%). Three of the 4 patients in group 4 had a remote history of classic vasodepressor syncope. The overall sensitivity and specificity of the test were 73 and 85%, respectively, while the predictive accuracy of a test with positive or negative outcome were 69 and 89%, respectively. Muscarinic receptor blockade with atropine in 4 patients prevented isoproterenolinduced bradycardia but not hypotension or symptoms of fainting. Beta-adrenergic receptor blockade with propranolol inhibited all aspects of the isoproterenol-induced faint. Thus, the administration of isoproterenol during a passive upright tilt may identify persons who suffer from or are prone to a vasodepressor reaction.
251 citations
TL;DR: During the procedure, arthroscopic fluid extravasated through the fracture site under pump pressure and resulted in an intraabdominal compartment syndrome that presented as cardiopulmonary arrest, which is a previously unreported potentially lethal complication.
Abstract: The case of a fifty-year-old man who suffered an isolated, associated, both-column fracture of the left acetabulum is presented. He underwent an uncomplicated open reduction and internal fixation through an ilioinguinal approach. A follow-up computed tomographic scan was performed postoperatively, which documented intraarticular fragments. Hip arthroscopy was performed to remove the fragments. During the procedure, arthroscopic fluid extravasated through the fracture site under pump pressure and resulted in an intraabdominal compartment syndrome that presented as cardiopulmonary arrest. An emergent exploratory laparotomy was performed to release the fluid and resume blood flow. Despite prolonged asystole, the patient survived without neurologic sequelae. The literature on compartment syndrome secondary to arthroscopic procedures is reviewed. Because of this previously unreported potentially lethal complication, we do not advocate hip arthroscopic procedures for acute or healing acetabular fractures.
167 citations
TL;DR: Although tachycardia was independently associated with hypotension, its sensitivity and specificity limit its usefulness in the initial evaluation of trauma victims and should not reassure the clinician about the absence of significant blood loss after trauma.
Abstract: Background Tachycardia is believed to be closely associated with hypotension and is often listed as an important sign in the initial diagnosis of hemorrhagic shock, but the correlation between heart rate and hypotension remains unproved. Study design Data were collected from all trauma patients, 16 to 49 years old, presenting to our university-based trauma center between July 1988 and January 1997. Moribund patients with a systolic blood pressure ≤ 50 or heart rate ≤ 40 and patients with significant head or spinal cord injuries were excluded. Tachycardia was defined as a heart rate ≥ 90 and hypotension as a systolic blood pressure Results Hypotension was present in 489 of the 14,325 admitted patients that met the entry criteria. Of the hypotensive patients, 35% (169) were not tachycardic. Tachycardia was present in 39% of patients with systolic blood pressure ≥ 120 mmHg. Hypotensive patients with tachycardia had a higher mortality (15%) compared with hypotensive patients who were not tachycardic (2%, p=0.003). Logistic regression analysis revealed tachycardia to be independently associated with hypotension (p = 0.0004), but receiver operating curve analysis demonstrated that the sensitivity and specificity of heart rate for predicting hypotension is poor. Conclusions Tachycardia is not a reliable sign of hypotension after trauma. Although tachycardia was independently associated with hypotension, its sensitivity and specificity limit its usefulness in the initial evaluation of trauma victims. Absence of tachycardia should not reassure the clinician about the absence of significant blood loss after trauma. Patients who are both hypotensive and tachycardic have an associated increased mortality and warrant careful evaluation.
149 citations
TL;DR: SI and Age x SI are better predictors of 48 MORT in injured patients than HR or SBP alone and should be used to identify patients at risk for early mortality following injury.
138 citations
Cites background from "Hemorrhagic shock with paradoxical ..."
...Advanced Trauma Life Support teaches that admission vital signs, particularly HR and SBP, can be used to determine the degree of shock a patient is in at the time of admission [22]....
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454 citations
TL;DR: The results show that the slowing of the heart, resulting from an emptying of the central blood reservoirs was correlated to, and preceded by, an increased activity in receptors located in the left ventricle and signalling in non-medullated afferents.
Abstract: Impulse activity in vagal afferent fibres and changes in heart rate were simultaneously recorded during rapid hemorrhage or blood pooling in cats in order to elucidate whether the sudden reflex bradycardia, sometimes evoked with the mentioned interventions, was correlated to an increased activity in any type of heart receptors. The results show that the slowing of the heart, resulting from an emptying of the central blood reservoirs was correlated to, and preceded by, an increased activity in receptors located in the left ventricle and signalling in non-medullated afferents. The receptors were found to be activated also by obstructions of the ascending aorta and mechanical stimulation of the heart, and therefore seem to operate as mechanorecepton, stimulated by a “distortion” of the myocardium. - It is conceivable that with rapid bleeding or pooling of blood, the receptors are excited by an improper squeezing of the myocardium when the ventricles contract vigorously around an almost empty chamber, and then induce a reflex bradycardia. This reflex mechanism, resembling the so-called vaso-vagal syncope reaction in man, may therefore serve as a protective system causing a break on the heart and allowing for an improved diastolic filling in situations when venous return is critically reduced.
354 citations
"Hemorrhagic shock with paradoxical ..." refers background in this paper
...Oberg and Thoren [10] suggested tha t this b radyca rd i a...
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279 citations
TL;DR: A variety of experimental approaches have been used to alter reflex parasympathetic cardiovascular control in normal human subjects and in patients with cardiovascular diseases and this review critically appraises several of these methods.
Abstract: A variety of experimental approaches have been used to alter reflex parasympathetic cardiovascular control in normal human subjects and in patients with cardiovascular diseases. This review critically appraises several of these methods (the Valsalva maneuver, upright tilt, lower body negative pressure, pressor drug infusion, neck suction, and coronary arteriography) and summarizes the normal response patterns of healthy subjects and the abnormal response patterns of some patients with cardiovascular disease. Tests of parasympathetic function tend to be heterogeneous; they are not standardized, and, therefore, valid comparisons between results from different studies may be difficult to make. Moreover, although most of these tests are simple to perform, they may provoke surprisingly complex alterations of afferent and efferent autonomic activity. Notwithstanding these methodological difficulties, the research area of human parasympathetic cardiovascular control may have great importance, because parasympathetic reflex mechanisms are involved in diseases of major public health significance for which animal models may be imperfect or nonexistent.
244 citations
"Hemorrhagic shock with paradoxical ..." refers methods in this paper
...Whenever possible survivors were tested with simple tests of parasympathetic functions [3]: upright tilt, carotid massage, oculocardiac reflex....
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TL;DR: LBNP proved to be a reproducible, effective and practical means to produce hypovolemia and induce vasodepressor syncope.
146 citations