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Biomedical subjects

M C Tomlanovich

Publications and source records attributed to M C Tomlanovich.

At least 37 records · Page 2Linked to original sources

Insulin and glucose levels during CPR in the canine model.

Cardiopulmonary arrest and resuscitation produces tremendous physiological stress with resultant biochemical derangements. We undertook this study to determine insulin and glucose levels during cardiopulmonary arrest in the canine model. Baseline insulin and glucose levels were obtained from an ascending aortic arch catheter in six mongrel dogs. Ventricular fibrillation was induced by an electrical stimulus and ventilation was terminated. After five minutes of fibrillation, cardiopulmonary resuscitation (CPR) was initiated using external, mechanical CPR and a continuous epinephrine infusion at 5 micrograms/kg/min. Serum insulin and glucose levels were repeated 15 minutes after beginning CPR. Mean blood glucose 15 minutes after initiation of resuscitation (379 +/- 114 mg/dL) was significantly increased from prearrest levels (124 +/- 29 mg/dL, P less than .01). Mean serum insulin 15 minutes after initiation of resuscitation (11.3 +/- 3.3 microU/mL) was significantly decreased compared to prearrest levels (16.2 +/- 6.0 microU/mL, P less than .05). During ischemia, the myocardium becomes dependent primarily on glucose as a source of energy. Inappropriately low insulin levels during CPR may adversely affect an already compromised myocardial glucose metabolism. Further investigation is needed to determine the utility of insulin infusion during CPR.

Animals↗

Immediate emergency department external cardiac pacing for prehospital bradyasystolic arrest.

Approximately 25% of patients in prehospital cardiac arrest present in bradyasystolic rhythms, and their long-term prognosis is very poor. Our study was undertaken to determine the utility of immediate emergency department (ED) external cardiac pacing in this situation. Twenty patients presenting with bradyasystolic prehospital cardiac arrest were entered in the study. All received the usual advanced cardiac life support therapy, but also were externally paced immediately using an automated external defibrillator and pacemaker (AEDP). Only two of 20 patients showed evidence of electrical capture, and none developed pulses with pacing. Four of the 20 patients developed a sinus rhythm and blood pressure during resuscitation. Three survived to leave the ED, but none survived to leave the hospital. An increase in the rate of bradycardia and pulseless idioventricular rhythms that was independent of electrical capture or pharmacologic therapy was noted occasionally. Although survival was not enhanced using the AEDP, the device was reliable, easy to use, and free of complications. External cardiac pacing warrants further investigation in the prehospital setting.

Adult↗

Comparison of central venous and arterial pH and PCO2 during open-chest CPR in the canine model.

Arterial blood gases are difficult to obtain during cardiopulmonary resuscitation (CPR) in human beings, and the possibility of venous sampling is raised frequently. The reliability of central venous gases as a substitute for arterial blood gases in assessing acid base status, however, has not been investigated adequately under conditions of CPR. Therefore, femoral arterial and central venous catheters were placed in 24 mongrel dogs, and ventricular fibrillation was electrically induced. After varying predetermined downtimes from five to 60 minutes, open-chest CPR was begun, and arterial and central venous blood gases were simultaneously drawn every five minutes during a 30-minute period. Arterial pH (pHa) was consistently higher than central venous pH (pHcv) by an average of .048 units. A significant correlation existed between the pHa and pHcv at all times during CPR, with an overall r = .9771 (P less than .0001). The difference between central venous PCO2 (PcvCO2) and arterial PCO2 (PaCO2) was 5.17 mm Hg prior to cardiac arrest, but it increased 300% to a mean of 15.51 mm Hg during CPR. Correction of pHcv using conventional methods to account for this respiratory component decreased the correlation between pHa and pHcv to r = .6905. The ability of pHcv to substitute for pHa was assessed, and showed a sensitivity of 100% when pHa of 7.2 was used as a criterion for treatment. In this model, pHcv is a sensitive indicator of pHa and it may be used to guide bicarbonate therapy. The increased PcvCO2 during CPR probably results from the marked tissue lactic acid production and subsequent shift of the bicarbonate buffer into free carbon dioxide.

Analysis of Variance↗

Ionized calcium during CPR in the canine model.

The purpose of our study was to determine ionized calcium levels during cardiopulmonary resuscitation (CPR). Following placement of ascending aortic catheters in 15 adult mongrel dogs, ventricular fibrillation was induced electrically. After five minutes without therapy, mechanical external CPR was instituted. Animals received either standard CPR (S-CPR, n = 8) or simultaneous compression and ventilation CPR (SCV-CPR, n = 7) for 30 minutes. Ionized calcium levels were obtained prior to fibrillation and every five minutes during CPR. Mean ionized calcium levels during CPR (1.27 +/- 0.06 mmol/L) did not differ significantly from prearrest levels (1.27 +/- 0.07 mmol/L) at any point during CPR. This was true when the dogs were analyzed together (P = 0.1293) and when the animals receiving S-CPR (P = 0.4465) and SCV-CPR (P = 0.5470) were analyzed by groups. Defibrillation was attempted in all animals and resulted in electromechanical dissociation in three. None of these dogs was hypocalcemic either prior to arrest or during CPR, and none developed an effective rhythm with the administration of calcium. Furthermore, three of the four animals receiving calcium developed markedly elevated ionized calcium levels. Hypocalcemia apparently does not occur during CPR. The beneficial effect of calcium in reported cases cannot be explained routinely by correction of hypocalcemia. Further studies are needed to define the role of calcium administration, if any, in CPR.

Animals↗

Verapamil in the treatment of asystolic and pulseless idioventricular rhythm cardiopulmonary arrests: a preliminary report.

A randomized, double-blinded study was conducted to evaluate the effectiveness of the calcium antagonist verapamil in patients in cardiopulmonary arrest with asystole or pulseless idioventricular rhythm (PIVR). Twenty-one such patients presenting to the emergency department received either verapamil (10 mg) or normal saline placebo in an intravenous bolus as initial therapy. They were then treated according to standard American Heart Association guidelines with the exception that calcium was not used. If these rhythms persisted after ten minutes, a second bolus of verapamil or saline was given. Resuscitation was successful in two of ten patients (20%) receiving verapamil and in one of 11 patients (9%) receiving placebo. This similar outcome (P = .462) in this small series suggests that verapamil may not add to successful resuscitation in these patients. Additional studies are needed to define the role of calcium and its antagonists in the treatment of asystole and PIVR.

Aged↗

Endotracheal bretylium tosylate in a canine model.

This study was conducted to determine whether bretylium tosylate (BT) is effectively and safely absorbed through the endotracheal route in the canine model. Eleven adult mongrel dogs were anesthetized with pentobarbital, were orally intubated, and had continuous blood pressure and electrocardiographic monitoring. Four dogs received 5 mg/kg BT, three dogs received 10 mg/kg BT, two dogs received 20 mg/kg BT, and two control dogs were given volumes of normal saline equal to those given the 5- and 10-mg/kg groups. Each dog received the same dose of BT both endotracheally and intravenously, but in a random order and on different dates. Following each drug administration arterial blood was drawn at various intervals over two hours and sent for immediate gas analysis; serum samples were frozen for future determination of BT levels. Regardless of the amounts delivered, the peak levels of BT in the arterial blood following administration by the endotracheal route were consistently low (4.13 micrograms/mL to 14.00 micrograms/mL) when compared to those levels following intravenously administered BT (120 micrograms/mL to 268 micrograms/mL) (all P less than .002 for the 5- and 10-mg/kg groups). No depot effect was observed during a two-hour period. The arterial blood gases did not change significantly following the administration of BT by the endotracheal route in the 5- and 10-mg/kg groups, and sections of these autopsied dog lungs showed no apparent pathologic changes.

Animals↗

Arterial blood gases and pulmonary function testing in acute bronchial asthma. Predicting patient outcomes.

Pretreatment and posttreatment arterial blood gas and pulmonary function testing measurements were prospectively compared as to their ability to assess asthma severity accurately and, thus, predict the outcome in 102 episodes of acute bronchial asthma initially seen in the emergency department. The Pao2, Paco2, or pH was unable to separate these patients requiring admission from those that could be confidently discharged, while the 1-s forced expiratory volume (FEV1) and peak expiratory flow rate (PEFR) did so both before and after treatment. Furthermore, virtually all patients with hypercarbia (Paco2 greater than 42 mm Hg) and/or severe hypoxemia (Pao2 less than 60 mm Hg) had a PEFR below 200 L/min, or an FEV1 below 1.0 L. Thus, selective use of arterial blood gas analysis should substantially decrease both diagnostic cost and patient discomfort without jeopardizing health care.

Acute Disease↗

Theophylline concentrations in the emergency treatment of acute bronchial asthma.

Ninety-three patients presenting with acute asthma to the emergency department were studied to determine theophylline levels and their relationship to airway obstruction, history of prior medication use, and side effects of treatment. The mean pretreatment theophylline level was 6.4 micrograms/ml. Patients on long-acting preparations had significantly higher levels than those on short-acting medications (p less than 0.05). The mean post-treatment theophylline level was 16.7 micrograms/ml. Twenty-three patients had toxic levels post-treatment but none of these had a major adverse reaction. Twenty of these patients had been taking long-acting preparations. Fifty percent of the patients with symptoms of gastrointestinal toxicity had theophylline levels below 15 micrograms/ml. There was no correlation between the theophylline level or change in level and the degree of airway obstruction as measured by pulmonary function testing. Clinical findings are not reliable predictors of theophylline levels. Patients taking long-acting theophylline products should receive a lowered loading dose.

Acute Disease↗

Pulmonary parenchymal injuries.

Pulmonary parenchymal damage is a frequent consequence of major trauma to the chest. Among the injuries considered in this article are traumatic pulmonary pseudocysts, pulmonary hematomas, major pulmonary lacerations, pulmonary contusions, and penetrating pulmonary parenchymal injuries. Also discussed is emergency resuscitation of patients with pulmonary parenchymal injuries.

Contusions↗

Resuscitative thoracotomy for patients with traumatic injury.

The clinical course and final outcome were determined for 63 trauma victims who underwent resuscitative thoracotomy (RT) for hypovolemic cardiac arrest in the Department of Emergency Medicine during a 24-month period. The objectives of the study were to determine the efficacy of and indications for RT and to define the prognostic signs for survival. Of 63 patients, six were successfully resuscitated (9.5%), and five of these were discharged from the hospital (7.9%). The presence of pupillary reactions was an extremely reliable indicator of successful outcome (P = 0.0009), as was the presence of some respiratory effort (P = 0.025). None of the victims of blunt trauma (n = 6) or severe head injury (n = 13) survived. Three of 17 patients (17.6%) with stab wounds and two of 36 (5.6%) with gunshot wounds survived the procedure. RT was beneficial in 13.6% of patients who had isolated organ system injuries, but no patient with injuries to more than two organ systems survived. Victims of isolated penetrating thoracic trauma had an 11.8% survival rate, as opposed to a 0% survival rate for those with abdominal trauma. The best prognosis was in victims with penetrating cardiac injuries, who had a 22.7% survival rate. The cost of RT averaged $1660 per patient, exclusive of physician charges. In our experience, RT is most beneficial for victims of penetrating thoracic trauma, especially those with cardiac injuries. However, routine use of this high cost/low benefit procedure cannot be recommended for patients who have cardiac arrest secondary to blunt trauma or severe head injuries. Also, it is not recommended for patients whose pupillary reflexes and respiratory movements are absent.

Adolescent↗

Comparison of peak expiratory flow and FEV1 admission criteria for acute bronchial asthma.

One hundred nine episodes of acute bronchial asthma were studied utilizing PEFR and FEV1 measurements to determine objective patient disposition criteria. Of patients with both a pre-treatment PEFR less than 100 L/min, and a post-treatment value less than 300 L/min, 92% required admission or had an unsuccessful OPD course. Of patients with a pre-treatment PEFR less than 100 L/min and an improvement less than 60 L/min after initial terbutaline, 85% were admitted or had problems after discharge. PEFR correlated well with FEV1 at all stages of treatment.

Acute Disease↗

Proximal saphenous vein cutdown.

An anatomical review and venesection technique for the proximal greater saphenous vein is described. It is recommended as an additional intravenous approach for rapid volume resuscitation in the patient with profound hypovolemic shock.

Humans↗

Bretylium tosylate as initial treatment for cardiopulmonary arrest: randomized comparison with placebo.

To evaluate the therapeutic effectiveness of intravenous bretylium tosylate as a first-line drug for patients in cardiopulmonary arrest, a randomized, double-blind study was conducted, comparing bretylium with a normal saline placebo. Fifty-nine patients presenting to the emergency department with cardiopulmonary arrest due mainly to ventricular fibrillation or asystole initially received either bretylium (10 mg/kg) or placebo in a rapid intravenous bolus and were then otherwise treated according to standard American Heart Association guidelines. If ventricular fibrillation or asystole persisted, a second bolus of bretylium or normal saline was given after 20 minutes. Thirty-five percent of patients presenting with ventricular fibrillation or asystole who received bretylium were successfully resuscitated, whereas 6% of patients who received placebo survived (P less than 0.05). These findings serve to suggest that the early use of bretylium tosylate in cardiopulmonary arrest improves survival.

Anti-Arrhythmia Agents↗