Mg Of Epinephrine Research Articles

Lower Extremity Hypothermia Is Beneficial During Infra-Renal Aortic Cross-Clamping in Pigs

The effects of lower extremity hypothermia during aortic cross-clamping are unknown. To compare the effects of lower extremity hypothermia with normothermia during aortic cross-clamping, two groups of six (25-40 kg) anesthetized pigs had their aortas cross-clamped below the renal arteries for 2 h. The cold group had their lower extremities cooled during cross-clamping to a quadriceps muscle temperature of 28°C by using convective cooling. The warm group had the quadriceps muscle temperature maintained at 38°C with convective warming. Saline, 0.9%, was used to maintain the pulmonary capillary wedge pressures at 5 mm Hg in both groups. Reperfusion of the lower extremities resulted in a small but significant decrease in the blood temperature from 36.6 ± 0.3°C (mean ± SE) to 35.6 ± 0.3°C 1 min after reperfusion in the cold group, but did not change the blood temperature in the warm group. Both the cardiac output and the lower extremity arterial flow were greater in the cold group at 1 and 5 min after cross-clamp release. Also one pig in the warm group required resuscitation with 1 mg of epinephrine intravenously to treat severe hypotension and myocardial depression after cross-clamp release. We conclude that hypothermia of the lower extremities may be beneficial for surgery involving aortic cross-clamping. (Anesth Analg 1993;77:241-9)

Hemodynamic effects of epinephrine in combination with different alkaline buffers during experimental, open-chest, cardiopulmonary resuscitation

To evaluate the hemodynamic actions of epinephrine combined with different alkaline buffers during experimental, open-chest, cardiopulmonary resuscitation (CPR). Prospective, randomized, controlled trial. Experimental animal laboratory in a university hospital. A total of 28 anesthetized piglets. After catheterization and application of a pulmonary artery flow probe (transit-time ultrasound flowmetry), the animals were stabilized. Induction of ventricular fibrillation was followed by a 15-min period of CPR, including manual heart compressions and mechanical ventilation with pure oxygen. On commencement of CPR, a 4-min alkaline buffer infusion began, with 50 mmol of sodium bicarbonate (n = 7), tris buffer mixture (n = 7), or tris buffer (n = 7), or, as a control (n = 7), the same volume of normal saline. After 8 mins of CPR, 0.5 mg of epinephrine was given intravenously; after 15 mins, direct current shocks were used to revert the heart to sinus rhythm. Blood flow measured in the pulmonary artery during open-chest CPR was approximately 20% of normal cardiac output. Administration of epinephrine reduced pulmonary artery flow irrespective of buffer. Sodium bicarbonate alone resulted in higher systemic blood pressure than pure tris: tris buffer mixture and normal saline were intermediate. Sodium bicarbonate combined with epinephrine tended to produce lower systemic blood pressure than other combinations. Experimental open-chest CPR generates pulmonary artery blood flows (20% of normal cardiac output) that are at best at the lower level of those blood flow rates previously reported (25% to 40% of normal cardiac output) from studies of closed-chest CPR. Different alkaline buffers influence circulatory and acid-base parameters differently before and after administration of epinephrine.

Effect of volume on spinal anesthesia level with hyperbaric tetracaine

The purpose of this prospective, randomized, double-blind study was to determine if the volume of a fixed milligram dose of hyperbaric tetracaine hydrochloride injected into the subarachnoid space affected the average maximal dermatomal spread of sensory anesthesia, determined by pinprick testing. One hundred two adults received spinal hyperbaric tetracaine in a volume of 2 mL, 3 mL, or 4 mL with the dose based on the patient's height. The addition of 0.2 mg of epinephrine to the anesthetic solution was allowed at the discretion of the attending anesthesiologist. A two-way analysis of variance (ANOVA) demonstrated that neither the dose selected nor the use of epinephrine affected anesthetic spread. ANOVA showed that anesthetic volume insignificantly affects the spread of sensory anesthesia. A Tukey HSD multiple comparisons test demonstrated a mean difference greater than 1 sensory dermatome between volumes of 2 mL and 4 mL, which was clinically detectable but statistically insignificant. Increasing the volume of hyperbaric spinal tetracaine solutions to improve anesthetic spread is unjustified.

Uptake and distribution of bupivacaine and morphine after intrathecal administration in parturients: effects of epinephrine.

This study examines the plasma pharmacokinetics of bupivacaine and morphine and the urinary excretion of morphine administered for spinal anesthesia for cesarean section. Patients received 12 mg of hyperbaric bupivacaine and 0.6 mg of morphine with either 0.2 mL of normal saline (plain, n = 15) or 0.2 mg of epinephrine (n = 15). Venous blood and urine were collected at 0, 0.25, 0.5, 1, 2, 3, 6, 12, and 24 h. Total and unconjugated morphine (UCM) in plasma and urine were measured using radioimmunoassay, and plasma bupivacaine was measured by gas chromatography. Results were expressed as mean +/- SE and analyzed using Student's t-test at P less than 0.05. In the epinephrine group, plasma bupivacaine peaked at 15 min and remained approximately 30% higher (P less than 0.05) at 0.25, 0.5, and 1 h than in the plain group, which peaked at 30 min. Although UCM peaked at 3 h in both groups, the plasma levels remained approximately 66% lower in the epinephrine group. In the epinephrine group, bupivacaine had a smaller volume of distribution at steady state, and morphine had a more rapid clearance, shorter t1/2 beta, and smaller area under the curve compared with the plain group (P less than 0.05). Only 45% +/- 5% and 31% +/- 3% of morphine was recovered in the urine in the plain and epinephrine group, respectively (P less than 0.05). In conclusion, epinephrine added to a bupivacaine-morphine mixture increases the initial systemic uptake of bupivacaine and decreases the absorption and urinary excretion of morphine from the intrathecal space.

Neurologically intact survivor of prolonged ventricular fibrillation: A case for intermediate dose epinephrine and postresuscitation infusion

The authors point out that our understanding of the optimal dose of epinephrine used in the resuscitation of patients in cardiac arrest continues to evolve. Doses greater than the standard 1 mg of epinephrine every 5 minutes have been studied and shown to increase the rate of return of spontaneous circulation. However, reports of neurologically intact survivors of prolonged cardiac arrest are rare. The authors report a neurologically intact survivor of prolonged ventricular fibrillation with severe mixed acidosis who responded to intermediate doses of epinephrine and epinephrine infusion, where standard amounts had failed. Further research should be directed into the relationship between postresuscitation epinephrine infusions and neurologic outcome.

Etude comparée de la rachianesthésie conventionnelle et de l'anesthésie rachidienne et péridurale conjointe dans la chirurgie gynécologique

A prospective study was carried out to compare the qualities of spinal block with those of combined spinal-epidural anaesthesia (CSEA). It included 63 patients, ranked ASA 1 or 2, aged between 35 and 75 years, scheduled for gynaecological surgery due to last more than 2 hours, and randomly allocated to two groups. In the first group (n = 34), spinal anaesthesia was carried out with the patients sitting, in the L 3–4 interspace, using 15 mg of hyperbaric bupivacaine with 0.4 mg of adrenaline. In the second group (n = 29), a catheter was inserted in the epidural space through the L 2–3 interspace, and spinal anaesthesia carried out as in the first group, using bupivacaine without adrenaline. Once the highest level of analgesia had been reached, aliquots of 0.5 % plain bupivacaine were injected through the epidural catheter, until anaesthesia of T 5 was obtained. In the spinal group, general anaesthesia was required in 3 cases, as anaesthesia only reached the T 12 level in 2 cases, and as surgery lasted longer than the spinal in the third one. In the CSEA group, excellent analgesia was obtained in all patients. Sensory blockade lasted 308 ± 48 min at the T 12 level, versus 162 ± 51 min in the spinal group (p < 0.025), and 361 ± 51 min at the L 2 level, versus 210 < 44 min in the other group (p < 0.025). « Topping upwas possible with the epidural catheter only, thus raising the level of sensory blockade, making it deeper, and increasing its duration. It avoids the use of general anaesthesia in case of failed spinal blockade. Pain relief may also be provided by this route. CSEA, a new approach to regional anaesthesia, combines the reliability of spinal blockade and the flexibility of epidural blockade.

The Dose of Epinephrine during Cardiopulmonary Resuscitation in Humans: What Should it Be?

The objective of vasopressor therapy during closed-chest cardiopulmonary resuscitation (CPR) is to augment coronary perfusion pressure so that spontaneous circulation can be reestablished. Epinephrine, an endogenous catecholamine with both alpha- and beta-adrenergic activity, is the vasopressor of choice for use during CPR. Epinephrine's potent alpha1-and alpha2-adrenergic effects improve cerebral and myocardial blood flow by preventing arterial collapse and by increasing peripheral vasoconstriction. The optimal dose of epinephrine in humans during closed-chest CPR is unknown. Studies suggest that the dose of epinephrine currently recommended during CPR may be five to ten times lower than the dose required to produce the beneficial pharmacologic effects observed in animal models of closed-chest CPR. Data from patients with prehospital cardiac arrest indicate that a 5-mg dose of epinephrine may be required to increase diastolic blood pressure above 30 mm Hg. Until additional data are available, our clinical experience suggests that all patients should receive at least one 1-mg dose of epinephrine. If the patient fails to respond, the administration of 3-5 mg of epinephrine every five minutes or the use of continuous infusions of epinephrine (0.2-0.6 mg/min) may be indicated.

The effect of epinephrine or norepinephrine on the duration of spinal anesthesia

The effect of vasocostrictors added to local anesthetic on the duration of spinal anesthesia was evaluated in sixty patients who were scheduled for lower extremity operations. They were randomly divided into four groups: Group C; 15 patients received Neopercamine S® (dibucaine 7.2mg, T-caine 3.6mg) 3ml alone. Group E1; 12 patients received Neopercamine S® 3ml added 0.1mg of epinephrine, Group E2; 15 patients received Neopercamine S® 3ml added 0.2mg of epinephrine, and Goup NE; 12 patients received Neopercamine S® 3ml added 0.1mg of norepinephrine. Segmental sensory blockade was assessed by pin prick at every 5min intervals for the first 30min after the intrathecal injection and thereafter at every 20min. Time for regression by two sensory dermatomes were significantly prolonged to 120±32min in the Group E1, 145±60min in the Group E2 and 142±55min in the Group NE, while it remained at 95±47min in the Group C. Time for regression by four sensory dermatomes were also prolonged to 178±35min in the Group E1, 191±68min in the Group E2 and 180±46min in the Group NE, while it remained at 135±52min in the Group C. No significant differences were noted in the analgesic duration between the groups.

Evaluation of the prognostic value of positive-contrast shoulder arthrography for bilateral osteochondrosis lesions in dogs

SUMMARY To investigate whether arthrographic findings had any prognostic value with respect to treatment and outcome of bilateral osteochondrosis, shoulder arthrograms (n = 80) from 40 dogs with bilateral lesions were evaluated. Arthrography was performed, using 1.5 to 4 ml of a 25% solution of meglumine-sodium diatrizoate, with admixture of 0.2 mg of epinephrine. A shoulder with signs of pain and lameness was surgically treated. The contralateral shoulder was treated conservatively, and the final outcome was compared with the arthrographic findings. In 37 dogs, signs of lameness and pain were associated with a loose cartilage flap and, in 3, with a detached cartilage flap. In 2 dogs, admitted with bilateral lameness, a loose cartilage flap was detected in both shoulders. Of 12 dogs with a detectable loose cartilage flap in the contralateral shoulder joint, 6 became lame 2 to 4 months after initial surgical intervention and needed bilateral surgery. In the contralateral joint, development of thick articular cartilage over the subchondral defect or a detached cartilage flap lodged in the caudal pouch of the shoulder joint was a favorable prognostic sign. Such dogs had no signs of lameness on the contralateral side during a follow-up period that ranged from 1 to 7 years.

Resuscitation from cardiac arrest using high-dose epinephrine

<h3>To the Editor. —</h3> I was most interested in the recent report by Drs Koscove and Paradis.¹I would like to comment on their references to work that the late J. S. Redding and I did more than 25 years ago, which are summarized in a small monograph.² We found that 1 mg of epinephrine worked well in resuscitating our dog models, which weighed about 10 kg each. In view of the extraordinary range of recommendations for human resuscitation in the contemporary literature, we tried this same dose in humans, and often it worked. I remember several children as young as 3 years old to whom 1 mg of epinephrine was given with good results. Our thought at that time was that a dose of 1 mg was to be the<i>minimal</i>initial dose for any adult. It may be of interest to recall that many cardiologists were

Resuscitation From Cardiac Arrest Using High-Dose Epinephrine

To the Editor. — I was most interested in the recent report by Drs Koscove and Paradis. 1 I would like to comment on their references to work that the late J. S. Redding and I did more than 25 years ago, which are summarized in a small monograph. 2 We found that 1 mg of epinephrine worked well in resuscitating our dog models, which weighed about 10 kg each. In view of the extraordinary range of recommendations for human resuscitation in the contemporary literature, we tried this same dose in humans, and often it worked. I remember several children as young as 3 years old to whom 1 mg of epinephrine was given with good results. Our thought at that time was that a dose of 1 mg was to be the minimal initial dose for any adult. It may be of interest to recall that many cardiologists were

Resuscitation From Cardiac Arrest Using High-Dose Epinephrine-Reply

In Reply. — We appreciate the attention devoted to our report by Drs Lacy and Kostis. However, we differ with them on some of their points. A review of our cases reveals that both patients did indeed fail to respond to conventional therapy. First, we stated that the patients failed to respond to therapy: this includes at least one or more standard doses of epinephrine, as well as other drugs and defibrillation. In case 1, even using the definition of response proposed by Drs Lacy and Kostis, the patient's junctional bradycardia present after intubation deteriorated to fine VF, and 1 mg of epinephrine... was given. Defibrillation... was performed with no change in rhythm; ie, the patient failed this round of conventional therapy. Whether the patient responded (using the definition of Drs Lacy and Kostis) to later rounds of conventional therapy cannot be determined unequivocally. We also note some inconsistency

Epinephrine Enhanced Positive Contrast Shoulder Arthrography in the Dog

Positive contrast shoulder arthrograms were obtained with and without the intra-articular injection of 0.2 mg of epinephrine in 6 experimental dogs and were compared after completion of the study. Radiographs were made 1, 3, 5, 9, 13, 17, 25 and 30 minutes after injection of the contrast medium. Admixture of epinephrine to the contrast medium resulted in an improvement in the sharpness of the contrast outlined joint structures as well as in the persistence of this enhanced detail on delayed radiographs. Detailed ECG recordings in 2 dogs during this procedure showed no abnormalities.

Sudden death in a young adult woman

0 Dr Carlo Musso: This case involves a 30-year-old woman who was apparently well, in her normal state of health playing softball, when after sliding into second base, stood up and then immediately collapsed. Her husband witnessed the incident, ran to her, and found her to be unresponsive and apneic. He began cardiopulmonary resuscitation (CPR) and had bystanders call 911. The paramedics arrived approximately four minutes later and determined that she was in full cardiac arrest with pupils fixed and dilated. She was found to be in a coarse ventricular fibrillation and underwent immediate defibrillation at 200 W/s, which converted her into asystole. She was orally intubated, and 1 mg of epinephrine was given via the endotracheal tube without a change in the rhythm. A peripheral intravenous line was started and 1 mg atropine and 1 mg epinephrine were administered. Soon after, the patient’s rhythm was noted to be in an accelerated idioventricular fibrillation that quickly deteriorated to ventricular fibrillation. She was defibrillated again with 200 W/s into a questionable supraventricular tachycardia with a rate of about 150 beats per minute and with a palpable carotid pulse. She was loaded into the ambulance and transported to Denver General Hospital’s emergency department, arriving approximately 20 min after the initial witnessed event. Her total down-time without a blood pressure was near 15 min according to the prehospital records. Immediately upon arrival, her vital signs were found to be a blood pressure of 124BOmm Hg and a heart rate of 150 beats per minute. She was being ventilated with 100% oxygen at a rate of 20 breaths per minute, and her rectal temperature was 38.1 “C. She was totally unresponsive to any painful stimuli. Her physical examination was remarkable for a l-cm hematoma over her right eyebrow, fixed and dilated pupils at 5 mm, and a colostomy present in the right lower quadrant of her abdomen. Within about five minutes, her pupils became minimally reactive. The cardiac monitor revealed a sinus tachycardia at a rate of 125. Further history was obtained from her husband revealing that she had experienced a headache for almost a week, associated with eye pain, for which she was being treated with acetaminophen and codeine. Her medical history was significant for the colostomy or ileostomy performed several years ago for severe colitis.

Calcium chloride in experimental electromechanical dissociation: a placebo-controlled trial in dogs.

While calcium administration has been recommended in CPR, its beneficial effects have been challenged. The effectiveness of calcium chloride was evaluated and compared with epinephrine during successive episodes of electromechanical dissociation (EMD) after ventricular fibrillation in closed-chest dogs. Each of three successive episodes of CPR was randomly and blindly treated by repeated (every 2 min) injections of 5 ml H2O plus either 500 mg of calcium chloride (CaCl2), 1 mg of epinephrine (Epi), or 5% dextrose (D5W). Of 42 CPR attempts performed on 16 dogs, 16 were reversed by only chest compression and artificial ventilation. For the 26 CPR with pharmacologic intervention, recovery was obtained after one injection in 5 of 6 Epi but only in 4 of 11 CaCl2 and 4 of 9 D5W. Only four CPR attempts were ultimately unsuccessful, all in CaCl2 group. During recovery, the Epi group showed significantly higher arterial pressures and heart rates but less severe acidemia. In this model, calcium chloride alone is ineffective during EMD.

Asystole with syncope following strenuous exercise in a man without organic heart disease

A 29-year-old man without organic heart disease who had a history of six episodes of syncope following sudden cessation of strenuous exercise over the last 18 years was reported. Resting electrocardiogram and 24-hour electrocardiographic monitoring did not show any rhythm disturbance or ischemic changes. Sinus node recovery time, sinoatrial conduction time and A-V conduction were normal on electrophysiologic study. Asystole with syncope occurred immediately following sudden cessation of strenuous exercise and following release of intrathoracic pressure during Valsalva's maneuver performed after subcutaneous administration of 0.5 mg of epinephrine. However, Master's single two-step test and Valsalva's maneuver performed without epinephrine could not evoke asystole. It was assumed from these results that transient overactivity of the autonomic nervous system and sympathetic-parasympathetic interactions were the underlying factors responsible for the occurrence of asystole following sudden cessation of strenuous exercise in the present case.

Intravenous epinephrine abuse

A 19-year-old man with a history of intravenous cocaine and amphetamine abuse injected 1.1 mg of epinephrine intravenously from an over-the-counter bronchodilator inhaler. Within seconds, headache, nausea, numbness of hands and feet, precordial chest discomfort, and palpitations developed. The patient was given a sublingual nitroglycerin tablet by a bystander and promptly had a syncopal episode. Hypotension was observed in the emergency department 10 minutes later. Administration of 2 L of Ringer's lactate maintained blood pressure at 80–90 mm Hg systolic. An electrocardiogram showed ischemic changes in the precordial leads. Cardiac enzymes remained normal. Mild hypokalemia and hyperglycemia were observed. This case illustrates an unusual route of abuse of an over-the-counter epinephrine bronchodilator.

Comparison of subcutaneous injection and high-dose inhalation of epinephrine—Implications for self-treatment to prevent anaphylaxis

The plasma concentrations of epinephrine were determined in healthy subjects administered epinephrine by subcutaneous injection of 0.5 mg or inhalation of 1.5 to 4.5 mg (10 to 30 inhalations from a metered-dose aerosol). The absorption of injected epinephrine was variable and in several cases very slow. The individual maximum values for epinephrine in plasma were 4.65 ± 1.09 (range 0.74 to 8.31) nmol/L, and these maxima were attained 5 to 120 minutes after injection. Inhaled epinephrine was rapidly and dose dependently absorbed. Ten inhalations resulted in 2.72 ± 0.84 (0.75 to 5.67) nmol/L within 5 minutes and 20 inhalations resulted in 7.19 ± 1.78 (2.10 to 13.83) nmol/L with rapid increases and maxima within 20 minutes in seven of eight subjects. Gastrointestinal side effects were dose limiting when epinephrine was administered by inhalation. Our results indicate that inhalation of 2 to 3 mg of epinephrine produces rapid increases of epinephrine concentrations in plasma to levels that have previously been demonstrated to counteract bronchoconstriction induced by inhaled allergen in subjects with asthma. Inhalation has several advantages over injection for self-administration of epinephrine, e.g., in patients who are allergic to insect (Hymenoptera) stings. Apart from the absorption being more rapid, the locally high concentrations of epinephrine in the airways should be advantageous, since bronchoconstriction is one of the life-threatening phenomena of the anaphylactic reaction. This route of administration is also simple for the patient.

Categorisation and causes of abnormal egg shells: relationship with stress.

Concern regarding the proportion of brown eggs being laid with abnormal egg shells led to an investigation of the relationship between disturbance or stress and egg shell appearance and quality. The abnormalities fell into two main classes: misshapen or bulging eggs and eggs coated with a superficial layer of amorphous calcium, variously termed dusted, white banded, chalky or pink eggs. Translocation of hens from pens to cages resulted in a decrease in egg production and an increase in the proportion of abnormal eggs over the succeeding 18 d. Disturbance to flocks on deep litter resulted in an increase in the proportion of eggs laid with abnormal shells on the following day, not only in the flocks directly affected but also in an adjacent flock. Exclusion from their nests of birds accustomed to laying in nest boxes resulted in disturbed prelaying behaviour, retention of eggs in the shell gland and an increased proportion of coated eggs. Administration of 0.1, 0.25 or 1.0 mg of adrenaline subcutaneously resulted in the retention of eggs currently in the hens' shell glands and in an increased proportion of eggs with abnormal egg shells being laid during the following 10 d. A dose response effect was apparent. There was evidence that the nature of the particular abnormality produced was dependent on the stage of egg formation at which the disturbance was imposed and, if retention followed, upon the length of time the egg was retained. Disturbances when eggs were only lightly calcified tended to result in misshapen eggs, while those occurring when oviposition was imminent tended to result in coated eggs. Dusted or pink eggs followed moderate retention whereas white banded eggs were seen after prolonged retention. These observations may provide a basis for a non-invasive method of assessing stress in laying hens as well as helping to account for hitherto inexplicable occurrences of declining egg shell quality.

Mechanical “cough” cardiopulmonary resuscitation during cardiac arrest in dogs

Hemodynamic findings during ventricular fibrillation (VF) and closed-chest cardiopulmonary resuscitation (CPR) are similar to those described during VF and vigorous coughing. Interventions during CPR that mimic the physiologic events of coughing (high intrathoracic pressure and high intraabdominal pressure) improve perfusion during VF and CPR. An external circulatory assist apparatus was devised to emulate cough physiology, i.e., simultaneous pulsatile increases in intrathoracic pressure (pneumatic vest), intraabdominal pressure (abdominal binder) and airway pressure (high-pressure airway inflation). In this study, vest/binder CPR was compared with conventional CPR during 30 minutes of VF and artificial support in 18 randomized dogs. Defibrillation and long-term (more than 24 hours) survival were chosen as end points. During VF and artificial support, aortic and right atrial (RA) pressures, the instantaneous aortic-RA pressure difference (coronary perfusion pressure) and blood gas levels were measured. After 30 minutes of VF and administration of 1 mg of epinephrine, countershock was attempted. Systolic aortic and RA pressures, mean aortic-RA pressure difference and blood gas levels were not significantly different between dogs that were successfully resuscitated and those that were not. However, peak diastolic coronary perfusion pressure (peak diastolic aortic-RA pressure) for survivors averaged 23 ± 6 mm Hg, but only 6 ± 10 mm Hg for nonsurvivors (p < 0.001). A peak diastolic coronary perfusion pressure 16 mm Hg or greater had a positive and negative predictive value for a successful outcome of 1.00. Only 1 of 9 conventional CPR dogs survived 24 hours; 7 of 9 dogs supported with the vest/binder device were alive and neurologically normal at 24 hours (p = 0.007). Thus resuscitation techniques that exploit the CPR “thoracic pump” can sustain systemic perfusion during VF, and diastolic coronary perfusion pressure is a determinant of CPR/countershock outcome and is favorably manipulated by mechanical means.