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D J Orban

Publications and source records attributed to D J Orban.

8 recordsLinked to original sources
PubMed1995

Automatic mechanical device to standardize active compression-decompression CPR.

STUDY OBJECTIVE: To develop an automatic mechanical device capable of performing active compression-decompression (ACD) CPR in laboratory animals. DESIGN: A swine model was used to study standard and ACD CPR. One-minute periods of standard mechanical chest compressions were alternated with mechanical ACD CPR. SETTING: University hospital laboratory. INTERVENTIONS: A commercially available device that provided standard chest compressions only was modified to deliver ACD CPR. RESULTS: The absolute difference in intrapleural pressure and tidal volume almost doubled during ACD CPR compared with that with standard CPR. CONCLUSION: The presence of a greater negative change in intrapleural pressure confirmed that active decompression of the chest had occurred and that the device was capable of performing ACD CPR. The device provides consistent rate, depth, force, and duty cycle.

Animals↗
PubMed1995

Does hypoxia or hypercarbia independently affect resuscitation from cardiac arrest?

STUDY OBJECTIVE: In a previous cardiopulmonary resuscitation (CPR) study in swine, ventilation was associated with improved rate of return of spontaneous circulation (ROSC) compared with nonventilated animals, which had greater hypoxia and hypercarbic acidosis. We used the same model to determine the independent effect of hypoxia and hypercarbic acidosis on ROSC after cardiac arrest. DESIGN: Laboratory model of cardiac arrest. SETTING: University teaching hospital laboratory. PARTICIPANTS: Domestic swine (23 to 61 kg). INTERVENTIONS: Twenty-four swine were randomly assigned to three groups receiving ventilation during CPR with 85% O2/15% N2 (control), 95% O2/5% CO2 (hypercarbia), or 10% O2/90% N2 (hypoxia). All animals had ventricular fibrillation for 6 min without CPR, then CPR with one of the ventilation gases for 10 min, then defibrillation. Animals without ROSC received epinephrine, 85% O2, CPR for another 3 min, and defibrillation. MEASUREMENTS AND RESULTS: During the tenth minute of CPR, the hypercarbic group had more mean (SD) arterial hypercarbia than the control group (PCO2, 47 +/- 6, compared with 34 +/- 6; p < 0.01), and greater mixed venous hypercarbia (PCO2, 72 +/- 14, compared with 59 +/- 8; p < 0.05), while mean arterial and mixed venous PO2 was not significantly different. The hypoxic group had significantly less mean arterial (43 +/- 9 compared with 228 +/- 103 mm Hg) and mixed venous (22 +/- 5 compared with 35 +/- 7 mm Hg) PO2 when compared with the control group (p < 0.01), while mean arterial and mixed venous PCO2 were not significantly different. Thus, the model succeeded in producing isolated hypercarbia without hypoxia in the hypercarbic group and isolated hypoxia without hypercarbia in the hypoxic group. The rate of ROSC was 6/8 (75%) for the control group, 1/8 (13%) for the hypercarbic group, and 1/8 (13%) for the hypoxic group (p < 0.02). CONCLUSIONS: Both hypoxia and hypercarbia independently had an adverse effect on resuscitation from cardiac arrest. In this model with a prolonged interval of untreated cardiac arrest, adequate ventilation was important for resuscitation.

Analysis of Variance↗
PubMed1994

Changes in arterial and mixed venous blood gases during untreated ventricular fibrillation and cardiopulmonary resuscitation.

This investigation was designed to evaluate the changes in arterial and mixed venous acid-base conditions during untreated ventricular fibrillation and after institution of cardiopulmonary resuscitation (CPR). Fifty-two swine (weight: 25-40 kg) were studied after induction of ventricular fibrillation. In a subgroup of 10 animals, 10-min CPR trials were performed. Arterial and mixed venous blood gases were monitored at baseline, after 5 min of untreated ventricular fibrillation (nonintervention interval) and after 10 min of mechanical CPR. Standard CPR was performed at compression rates of 100/min with a 60% duty cycle. Arterial pH, Pco2, and HCO3 were unchanged when baseline values were compared with those obtained after 5 min of untreated ventricular fibrillation, while arterial Po2 decreased from 81 to 69 torr. Mixed venous pH decreased from 7.41 to 7.35, Pco2 increased from 43 to 48 torr, Po2 decreased from 40 to 38 torr and HCO3 decreased from 28 to 26 mEq/l (P < 0.05). Although these changes were statistically significant, many remain in the normal range. Both arterial and mixed venous pH and HCO3 fell further after 9 min of CPR and Pco2 increased (P < 0.05). Alterations in mixed venous pH and Pco2 were more apparent than corresponding changes in arterial blood gas composition. We conclude that untreated cardiac arrest may be accompanied by normal arterial and mixed venous blood gas levels. Tissue acidosis is only revealed after tissue perfusion is restored and is most accurately reflected in the mixed venous blood gas composition. This apparent paradox provides insight into the relationship between tissue perfusion and arterial and mixed venous acid-based composition.

Acid-Base Equilibrium↗
PubMed1994

Effect of ventilation on resuscitation in an animal model of cardiac arrest.

BACKGROUND: The need for ventilation during the initial management of cardiac arrest is an important public health problem that is being debated. The present study was designed to determine whether ventilation affects return of spontaneous circulation from cardiac arrest in a swine model with an interval of untreated ventricular fibrillation of 6 minutes, as reported in witnessed out-of-hospital human cardiac arrest. METHODS AND RESULTS: Twenty-four animals were randomly assigned to two groups: one that received ventilation during the first 10 minutes of chest compression and one that did not. Coronary perfusion pressure and minute ventilation were continuously recorded. Arterial and mixed venous blood gases were measured at intervals. Return of spontaneous circulation was defined prospectively as an aortic systolic blood pressure of > 80 mm Hg for > 5 minutes and was the primary outcome variable. All animals were anesthetized, paralyzed, and intubated. Ventricular fibrillation was induced and persisted for 6 minutes without chest compression, followed by mechanical chest compression for 10 minutes and then attempted defibrillation. Animals without return of spontaneous circulation were given epinephrine, ventilation, and chest compression for an additional 3 minutes. Defibrillation was again attempted, and animals were assessed for return of spontaneous circulation. There were no significant differences between the two groups in baseline prearrest mean cardiac index, coronary perfusion pressure, or arterial and mixed venous blood gases. However, after 9 minutes of chest compression, significant differences were noted between the ventilated and nonventilated groups. The nonventilated group had significantly (P < .05) lower mean arterial PO2 (38 +/- 17 mm Hg compared with 216 +/- 104 mm Hg) and higher PCO2 (62 +/- 16 mm Hg compared with 35 +/- 8 mm Hg), lower mixed venous PO2 (15 +/- 7 mm Hg compared with 60 +/- 7 mm Hg). Nine of 12 (75%) of the ventilated animals, and only 1 of 12 (8%) of the nonventilated animals had return of spontaneous circulation after cardiac arrest (P < .002). CONCLUSIONS: In this animal model of cardiac arrest, ventilation was important for resuscitation. The importance of ventilation could be related to the prolonged duration of untreated ventricular fibrillation and the significantly greater hypoxia and hypercarbic acidosis found in the nonventilated animals.

Animals↗
PubMed1993

The choice of thrombolytic agents in the emergency department.

STUDY OBJECTIVE: To assess the choice of thrombolytic agents in emergency departments and whether administrators and third-party payers are influencing choices because of cost differences. DESIGN: A telephone survey. TYPE OF PARTICIPANTS: ED medical directors, stratifying for hospital ownership, size, and regions of the United States. MEASUREMENTS AND MAIN RESULTS: One hundred twenty-three ED medical directors completed the interview. Findings indicate that formularies include recombinant tissue-type plasminogen activator (rt-PA) in 94.3% of surveyed hospitals and streptokinase in 63.4%. Public hospitals were significantly less likely to have rt-PA on the formulary (P = .0001). Based on payer type, 68.9% to 77.5% of patients requiring thrombolysis receive rt-PA, with approximately 15% of EDs using it for 1% to 25% of patients and an additional 15% using it for 26% to 50% of patients. Fourteen medical directors (11%) reported that they delay treatment with rt-PA until authorization is provided by the health maintenance organization, and 40% indicated they would change their choice of agents if rt-PA was denied. Cardiologists were the primary decision makers regarding thrombolytic agents in all types of hospitals. CONCLUSION: Although rt-PA is the most frequently selected thrombolytic agent, significant practice variations exist among hospitals. To avoid interference from third-party payers and administrators, physicians may need to make decisions regarding such expensive agents in more objective forums (eg, pharmacy and therapeutics committees) and be better prepared to defend the resulting practice guidelines.

Decision Making, Organizational↗
PubMed1983

Esophageal perforation following use of esophageal obturator airway (EOA).

Esophageal perforation following use of the esophageal obturator airway (EOA) has been reported in a small number of patients. However, it has generally been discovered only in the presence of obvious clinical signs in patients otherwise resuscitated from cardiac arrest. Since it may well be overlooked in patients who succumb following the combined insult or primary cardiac arrest and secondary esophageal perforation, the true incidence of this adverse consequence of EOA use is unknown. We present a case of esophageal intubation with the EOA, and review in detail previous reported cases. We further suggest possible mechanisms leading to this catastrophic consequence of intubation with the EOA, and comment on its significance with regard to the controversy over EOA versus endotracheal (ET) tube training for paramedic pre-hospital personnel.

Adult↗
PubMed1981

Application of the Cardiotrak pacemaker monitor to prehospital care.

The Cardiotrak is a small, lightweight device originally developed for use by pacemaker patients to transmit their electrocardiograms (ECGs) by telephone to their doctor or to a hospital. The Cardiotrak seemed well suited for use by paramedics and was field tested on 76 patients. In 69 patients, clear ECGs were transmitted with ease; in the remaining seven, only minor, correctable problems were noted. The Cardiotrak appears to have advantages over other devices used to transmit ECGs to base station hospitals from paramedics.

Arrhythmias, Cardiac↗