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Biomedical subjects

E R Gonzalez

Publications and source records attributed to E R Gonzalez.

At least 55 records · Page 3Linked to original sources
PubMed1988

Treatment of paroxysmal supraventricular tachycardia in the emergency department by clinical decision analysis.

Vagal maneuvers terminate new onset, catheter-induced paroxysmal supraventricular tachycardia (PSVT) in up to 92% of patients. The risk and benefit of vagal maneuvers for treating PSVT in the emergency department (ED) is inadequately defined. The purpose of this study was to determine the efficacy of nonpharmacological vagal interventions in converting spontaneous episodes of PSVT in adult patients and to derive a treatment plan for such patients based on clinical decision analysis. Seventeen adult patients who presented to the ED because of PSVT were treated with carotid sinus massage, Valsalva maneuver, and head-down tilt (alone and in combination). Only three patients converted out of PSVT with vagal intervention. The remainder received verapamil, which converted 12 of the 14 patients (86%) who received the drug (one required digoxin, one required synchronized cardioversion). Vagal maneuvers are safe in young, otherwise healthy patients but problems have been documented in the literature in older patients, who have a higher likelihood of coronary and/or cerebrovascular disease. Clinical decision analysis indicates that young patients should be treated initially with vagal maneuvers but that older patients (above approximately 65 years of age) should be treated initially with verapamil.

Adult↗
PubMed1988

Comparison of intramuscular analgesic activity of butorphanol and morphine in patients with sickle cell disease.

This double-blind study compared the analgesic effects of morphine with those of butorphanol in patients who presented with pain because of sickle cell crisis. Patients were placed at bed rest, administered IV hydration, and randomly assigned on each visit to receive either 2 mg IM butorphanol or 6 mg IM morphine every 30 to 60 minutes as needed to produce a pain intensity of 50 mm or less on the linear analog pain scale until the patient was discharged. Linear analog scale for pain and pain relief, level of alertness, and vital signs were assessed at 60 and 120 minutes after each study drug dose, before additional doses, and at discharge. Eighteen patients (12 men, six women; mean age, 29.3 +/- 7.7 years) were studied. Six received only morphine, six received only butorphanol, and six received each treatment at some time during the study period, resulting in 45 randomizations to treatment. The two therapies did not differ significantly (P greater than .40) with respect to pain or relief of pain scores, level of alertness, or vital signs. The discharge rate was 69.6% and 68.2% with morphine and butorphanol, respectively (P = .92). The incidence of adverse effects was 13% and 23% with morphine and butorphanol, respectively (P = .46). We conclude that morphine and butorphanol are equally effective in the treatment of sickle cell crisis pain.

Adolescent↗
PubMed1988

Effect of cardiopulmonary resuscitation compression rate on end-tidal carbon dioxide concentration and arterial pressure in man.

The optimal rate of chest compression during CPR in man has been debated. Recently, the end-tidal carbon dioxide concentration (PetCO2) has been shown to correlate with cardiac output during CPR in experimental animals. Eighteen prehospital cardiac arrest patients were studied to determine the effect of external chest compression rate on the PetCO2 and BP in man when ventilation rate, ventilation inspiration time, applied compression force, and a 50:50 downstroke:upstroke ratio were held constant using a microprocessor-controlled CPR Thumper. Compression rate was increased from 60 to 140/min in 20 beat/min increments. The PetCO2 was 1.7 +/- 0.2% at a compression rate of 60/min and did not change significantly at increased rates. Systolic BP fell progressively from 59 +/- 5 mm Hg at 60/min to 46 +/- 4 mm Hg at 140/min. Diastolic BP remained approximately 23 mm Hg at all rates studied. Using a CPR manikin, we found that greater Thumper compression force was necessary to sustain the same sternal displacement and to achieve the same applied sternal pressure when the rate was increased due to a rate-limited fall in the compression duration.

Aged↗
PubMed1988

Vasopressor effect of epinephrine with and without dopamine during cardiopulmonary resuscitation.

We prospectively studied nine prehospital cardiac arrest patients (six M, three F; aged 60 +/- 8 yr) to determine the vasopressor response following incremental (1, 3, and 5 mg) doses of intravenous epinephrine given 5 minutes apart with or without dopamine 15 micrograms/kg/min. All patients were in ventricular fibrillation on arrival of the paramedics and were not resuscitated with standard advanced cardiac life support therapy. Cardiopulmonary resuscitation (CPR) was performed with a computerized Thumper at 60 compressions/min with a 50:50 downstroke-to-upstroke ratio. All patients were intubated and received 12 ventilations/min at a fraction of inspired oxygen of 80 percent. Radial artery pressure was monitored through a #20 gauge radial artery catheter inserted by cutdown within ten minutes after arrival at the emergency room. Five patients received epinephrine alone (group A) and four received epinephrine plus dopamine (group B). The patient's age, paramedic response time, arterial blood gases, and initial diastolic blood pressure (BP) did not differ significantly between treatment groups. Baseline systolic BP was significantly higher (p less than 0.01) in group B (68 +/- 10 mm Hg) than in group A (35 +/- 5 mm Hg). Epinephrine produced a dose-dependent vasopressor response in group A, but not in group B. In group A, peak systolic BP following epinephrine 1, 3, and 5 mg was 57 +/- 20, 69 +/- 23, and 76 +/- 27 mm Hg, respectively (p less than 0.05 for 5 mg vs. baseline). No statistically significant difference was observed among the respective values in group B (81 +/- 13, 80 +/- 18, and 78 +/- 19 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Respiratory complications of gastroesophageal reflux.

Gastroesophageal reflux may predispose patients to pulmonary complications such as bronchospasm and aspiration pneumonitis. This is especially true in patients who are critically ill, those with reflux-induced asthma and those undergoing general anesthesia. Decreasing the amount of acid reflux reduces the potential for respiratory complications. In patients at risk, administration of H2-receptor antagonists minimizes the risk of acid aspiration and resolves asthma symptoms.

Gastroesophageal Reflux↗
PubMed1987

Dopamine-induced increase in atrioventricular conduction in atrial fibrillation-flutter.

We report a patient with controlled atrial fibrillation-flutter (AFF) and mitral stenosis who developed a marked increase in atrioventricular conduction during an infusion of low dose dopamine with development of hemodynamic compromise. This side effect has not been previously described in humans. Dopamine infusion should be used with caution in patients with AFF.

Atrial Fibrillation↗
PubMed1987

Cimetidine versus ranitidine: single-dose, oral regimen for reducing gastric acidity and volume in ambulatory surgery patients.

This placebo-controlled trial compared the efficacy of single oral doses of cimetidine or ranitidine in maintaining intragastric pH and volume greater than 2.5 and less than 25 ml, respectively, in ambulatory surgery patients requiring general anesthesia. Patients were randomized to receive either placebo, ranitidine HCl 150 mg, or cimetidine HCl 400 mg upon rising on the morning of surgery. At induction, the cimetidine and ranitidine groups had significantly higher (p less than 0.05) gastric pH values than the placebo group. At extubation, the ranitidine group had a significantly higher (p less than 0.05) gastric pH than either the cimetidine or placebo group. Both H2-blocker groups had lower volumes when compared with the placebo group at extubation (p less than 0.05). There were more patients at risk for aspiration pneumonitis (pH less than 2.5 and/or volume greater than 25 ml) in the cimetidine group (46 percent) than in the ranitidine group (15 percent). All placebo-treated patients were at risk for aspiration pneumonitis. We did not find subjective clinical evidence of aspiration pneumonitis in our patients. We conclude that both ranitidine and cimetidine are superior to placebo, but ranitidine may be the preferred agent because of its more consistent effect on gastric pH and volume.

Adult↗
PubMed1986

Bacterial contamination of ambulance oxygen humidifier water reservoirs: a potential source of pulmonary infection.

The risk and benefit of oxygen humidification during ambulance transport is unknown. We cultured the water in plastic multiple-use bottles of humidifiers on 30 randomly selected area ambulances during November 1985. There were 22 positive cultures. Potentially pathogenic bacteria (four Pseudomonas maltophilia, three Pseudomonas aeruginosa, one Klebsiella pneumoniae, and one Staphylococcus epidermidis) were found in nine samples. Assuming that the water in ambulance humidifiers should have been sterile, the findings are statistically significant (P less than .01). Because there is no evidence that humidification is of benefit for nonintubated patients receiving oxygen at flow rates of 4 L/min or less when environmental humidity is adequate, we suggest that such patients should receive oxygen without humidification during ambulance transport. All other patients requiring oxygen during ambulance transport should continue to receive humidified oxygen. If a multiple-use humidifier reservoir is to be used, a written policy for its use must be developed and there must be appropriate documentation of compliance with the policy. An alternative is to replace the multiple-use humidifier reservoir with single-use sterile disposable devices, which cost approximately $2.00 per unit.

Ambulances↗
PubMed1985

Rapid change in pulmonary vascular hemodynamics with pulmonary edema during cardiopulmonary resuscitation.

Previous studies have shown that pulmonary edema occurs in half of all pre-hospital cardiac arrest victims who cannot be successfully resuscitated and is a major cause of hypoxemia and poor lung compliance during resuscitation. Pulmonary vascular hypertension and elevation of pulmonary capillary wedge pressure have been observed during cardiac resuscitation in humans. To further define the time course of the pulmonary hemodynamic changes, pulmonary artery diastolic pressure (PAd) was measured on a computerized trend recorder prior to, during, and immediately after arrest in three adult patients. Prior to arrest, PADP was 20.9 +/- 3.1 mm Hg. The PADP rose in all three patients by an average of 30.6% after 5-10 minutes and 71.3% after 10-15 minutes of CPR. Peak PADP reached 35.8 +/- 5.1 mm Hg (difference from pre-arrest level significant, P less than 0.001). In both patients who were resuscitated successfully, the PADP returned to baseline within 5 minutes of effective spontaneous circulation. The finding that such hemodynamic changes occur rapidly during resuscitation and can reverse quickly with resumption of effective spontaneous circulation is consistent with the time course for the early development of pulmonary edema. Development of pulmonary edema many hours following successful resuscitation likely involves other mechanisms.

Blood Pressure↗
PubMed1985

Arterial pH in out-of-hospital cardiac arrest: response time as a determinant of acidosis.

It is unclear why some victims of out-of-hospital cardiac arrest are severely acidotic on arrival to the emergency department (ED), whereas others have a pH within normal limits. To explain the difference among patients, the authors collected data on 119 consecutive out-of-hospital adult nontraumatic cardiac arrest victims brought to the University of Nebraska Medical Center by paramedic rescue squad between December 1982 and January 1984. Patients who experienced restoration of spontaneous circulation (ROSC) in the field had a normal pH (7.40 +/- 0.13) as compared with the pH of patients still receiving cardiopulmonary resuscitation (CPR) on arrival at the ED (7.18 +/- 0.20). A rapid paramedic response time was the best determinant of ROSC and a normal pH on arrival at the ED. Bystander CPR neither significantly increased the number of patients with ROSC in the field nor protected against the development of acidosis, but did improve the neurological outcome of survivors. The presence of acidosis in patients still receiving CPR on arrival in the ED could not be predicted on the basis of paramedic response time, amount of sodium bicarbonate given in the field, whether or not the collapse was witnessed, or whether or not bystander CPR had been performed. Patients who were acidotic had a significantly higher (P less than 0.001) Paco2 (101 +/- 33 mm Hg) and a lower Pao2 (41 +/- 69 mm Hg) than patients with a normal pH (Paco2 37 +/- 10 mm Hg, Pao2 134 +/- 107 mm Hg). Adequacy of ventilation is the principal determinant of acidosis in patients who are still receiving CPR on arrival at the ED.

Acidosis↗
PubMed1985

Incidence and causes of hypokalemia associated with cardiac resuscitation.

To further investigate the incidence and etiology of hypokalemia during cardiac arrest, the authors compared data on 74 adult nontrauma cardiac arrest patients (44 men, 30 women, age 65 +/- 13 years) who had a serum potassium (K+) level documented during or immediately following resuscitation with data on 53 adult controls with life-threatening medical emergencies presenting to the emergency department who did not experience arrest. Hypokalemia (serum K+ less than 3.6 mEq/l) occurred in 25 arrest patients (34%) compared with nine controls (17%). Serum K+ was not significantly different shortly before (3.7 +/- 0.4) versus immediately after arrest (3.6 +/- 0.8) in a small subgroup of patients, making intracellular shifting of K+ because of metabolic events during resuscitation an unlikely etiology. Hypokalemia was associated with a 2.5-fold increase in relative risk for cardiac arrest. Patients who were receiving diuretics without K+ supplementation had the highest risk of arrest (4.4-fold increase). Supplementation of K+ appeared to be protective in patients on diuretics. The authors confirm the association between hypokalemia and cardiac arrest and suggest that this metabolic abnormality may be an important risk factor for cardiac arrest.

Adult↗
PubMed1985

Prophylaxis of stress ulcers: antacid titration vs. histamine2-receptor blockade.

The near universal occurrence of stress ulcers in critically ill patients emphasizes the need for early and effective prophylaxis. Intraluminal gastric acidity, ischemic insult to the bowel, and the presence of stress factors are the major precipitants of stress ulcers. The use of H2-receptor antagonists vs. antacid titration for stress ulcer prophylaxis is reviewed. The goals of preventive therapy are to eliminate the stress factors and to maintain intragastric pH greater than 5. Hourly gastric pH monitoring and antacid titration are the mainstay of stress ulcer prophylaxis, with high potency antacids being the preferred agents. H2-receptor antagonists may serve as adjuncts in patients requiring large doses of antacids or having acid-base abnormalities from high gastric output states.

Antacids↗