Biomedical subjects

A H Idris

Publications and source records attributed to A H Idris.

41 records · Page 3Linked to original sources

PubMed1994

The composition of gas given by mouth-to-mouth ventilation during CPR.

STUDY OBJECTIVE: To compare the concentration of a rescuer's exhaled O2 and CO2 during mouth-to-mouth ventilation with or without chest compression. DESIGN: Prospective repeated measures study. Simulated one- and two-rescuer cardiopulmonary resuscitation (CPR) was performed as recommended by the American Heart Association. SETTING: University laboratory. PARTICIPANTS: Fifty-five healthcare professionals certified in basic and advanced cardiac life support volunteered as rescuers in this study. MEASUREMENTS AND RESULTS: Thirty-three volunteers performed one-rescuer CPR, and 22 volunteers performed two-rescuer CPR. Minute ventilation for both groups increased 50% to 130% during CPR (p < 0.05). During the performance of CPR, the concentration of exhaled O2 increased from 16.4 +/- 0.7% to 16.9 +/- 0.5% in the one-rescuer CPR group and from 16.5 +/- 0.9% to 17.8 +/- 0.6% in the two-rescuer CPR group (p < 0.05). The concentration of exhaled CO2 in the one-rescuer CPR group did not change significantly throughout the entire experiment, but decreased in the two-rescuer CPR group from a baseline measurement of 4.0 +/- 0.6% to 3.5 +/- 0.4% (p < 0.05). During CPR, the concentration of exhaled CO2 was 4.0 +/- 0.4% in the one-rescuer CPR group compared with 3.5 +/- 0.4% in the two-rescuer CPR group (p < 0.05). CONCLUSIONS: The gas given by mouth-to-mouth ventilation is a hypercarbic and hypoxic mixture compared with room air. Mouth-to-mouth ventilation is the only circumstance in which a hypercarbic and hypoxic gas is given as therapy. Further laboratory and clinical studies are necessary to determine the effect of mouth-to-mouth ventilation during CPR.

Carbon Dioxide↗

PubMed1994

Effect of ventilation on acid-base balance and oxygenation in low blood-flow states.

OBJECTIVES: To investigate how minute ventilation affects the partial pressure of end-tidal CO2 and arterial and mixed venous pH, PCO2, PO2, and the concentration of bicarbonate during low blood-flow states. We tested the null hypothesis that acid-base conditions during low rates of blood flow are not significantly different when minute ventilation is doubled or halved. DESIGN: Prospective, experimental, animal study. SETTING: University hospital laboratory. SUBJECTS: Domestic swine. INTERVENTIONS: We studied ten anesthetized and mechanically ventilated swine (weight, 43 to 102 kg) in a new model of controlled systemic and pulmonary blood flow in which each animal was maintained on ventricular assist devices. After electrical induction of ventricular fibrillation, ventricular assist device blood flow was decreased in steps. At each decrease, control minute ventilation, two times the control minute ventilation (hyperventilation), and one-half the control minute ventilation (hypoventilation) were administered; each ventilatory change was maintained for 6 mins. MEASUREMENTS AND MAIN RESULTS: Aortic, pulmonary arterial and central venous pressures, ventricular assist device blood flow, and end-tidal CO2 were recorded continuously. Acid-base conditions were studied at three different mean blood flow rates: 49%, 30%, and 12% of baseline prearrest cardiac index. Arterial pH and PaO2 and mixed venous pH varied directly (p < .003) with minute ventilation, while PaCO2 and mixed venous PCO2, and end-tidal CO2 varied inversely (p < .0001) with minute ventilation. Mixed venous PO2 was not significantly related to minute ventilation (p = .6). PaCO2 and arterial bicarbonate; mixed venous pH, mixed venous PO2, and mixed venous bicarbonate, and end-tidal CO2 varied directly (p < .001) with blood flow, while mixed venous PCO2 varied inversely with blood flow (p < .05). Arterial pH was not significantly related to blood flow (p = .3). When minute ventilation changed from hyperventilation to hypoventilation at a mean blood flow rate of 49%, mean arterial pH decreased 0.22 +/- 0.06 (p < .05), mean PaCO2 increased 28 +/- 6 torr (3.7 +/- 0.8 kPa) (p < .05), and mean PaO2 decreased 99 +/- 77 torr (13.2 +/- 10 kPa); mean mixed venous pH decreased 0.11 +/- 0.02, mean mixed venous PCO2 increased 16 +/- 2.2 torr (2.1 +/- 0.3 kPa) (p < .05), and mean mixed venous PO2 did not change; mean end-tidal CO2 increased 18 +/- 2 torr (2.4 +/- 0.3 kPa) (p < .05). The effect of changes in minute ventilation on blood gases and end-tidal CO2 was similar for mean blood flow rates of 30% and 12% of baseline cardiac index. CONCLUSIONS: During low rates of blood flow similar to those rates found in shock and cardiopulmonary resuscitation, alterations in minute ventilation significantly influenced end-tidal CO2 and both arterial and mixed venous pH and PCO2. These findings may have clinical importance in improving the treatment of shock and cardiac arrest.

Acid-Base Equilibrium↗

PubMed1993

Emergency department treatment of severe asthma. Metered-dose inhaler plus holding chamber is equivalent in effectiveness to nebulizer.

STUDY OBJECTIVE: To compare the effectiveness of administration of albuterol by nebulizer or by a metered-dose inhaler having a holding chamber attachment (hereafter "inhaler") for treatment of acute asthma in an emergency department (ED). DESIGN: A randomized, double-blind, placebo-controlled intervention study conducted at two sites. SETTING: The EDs of a large municipal hospital and a university teaching hospital. PATIENTS: Thirty-five patients 10 to 45 years of age seeking treatment at an ED for acute asthma. INTERVENTIONS: Patients were randomly assigned to receive either albuterol by nebulizer plus placebo by inhaler (n = 20) or albuterol by inhaler plus placebo by nebulizer (n = 15). The dose was repeated every 30 min until the FEV1 was at least 80 percent of predicted, the patient became asymptomatic, or 6 doses had been given. MEASUREMENTS AND RESULTS: All references in this article to spirometric measurements of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and peak expiratory flow rate (PEFR) represent percentages of the predicted normal value. No significant (p > 0.58) differences occurred in baseline mean FEV1, FVC, or PEFR for the two groups. For both groups, significant improvement occurred in mean FEV1 at 30 min (p < 0.02) and at 60 min (p < 0.02), and in maximum mean FEV1 (p < 0.001). However, no significant (p > 0.6) differences occurred between groups in mean FEV1, FVC, or PEFR at 30 and 60 min, or in maximum improvement attained. The sample size was sufficiently large to detect a 12 percent difference in improvement with a power of 90 percent. Thirty-three of 35 patients were treated successfully with the study protocol, became asymptomatic, and were discharged home. One patient from each group required further treatment. CONCLUSIONS: There was no detectable difference in effectiveness of albuterol administered by nebulizer or the inhaler system for treatment of acute asthma. There was no detectable difference in effectiveness of albuterol administered by nebulizer or the inhaler system for the treatment of acute asthma when the dose was titrated to clinical response. When compared with nebulizer, the metered-dose inhaler with holding chamber delivers a full dose of albuterol more quickly and at no higher cost.

Administration, Inhalation↗

PubMed1992

High-flow sheaths for pediatric fluid resuscitation: a comparison of flow rates with standard pediatric catheters.

We evaluated high-flow intravenous devices designed specifically for fluid resuscitation of infants and children. Fluid flow rates with 4-, 5-, and 6-Fr high-flow sheaths and 18-, 20-, and 22-gauge catheters were measured and compared. Flow rate is significantly faster with the 4-Fr sheath (P less than 0.0001) than with the 18-, 20-, or 22-gauge catheter. The high flow rates possible with the sheaths make them ideal for use in patients who require rapid fluid resuscitation.

Catheterization↗

PubMed1986

Transfers to a public hospital. A prospective study of 467 patients.

In recent years there has been a dramatic increase in the number of patients transferred to public hospitals in the United States. We prospectively studied 467 medical and surgical patients who were transferred from the emergency departments of other hospitals in the Chicago area to Cook County Hospital and subsequently admitted. Eighty-nine percent of the transferred patients were black or Hispanic, and 81 percent were unemployed. Most (87 percent) were transferred because they lacked adequate medical insurance. Only 6 percent of the patients had given written informed consent for transfer. Twenty-two percent required admission to an intensive care unit, usually within 24 hours of arrival. Twenty-four percent were in an unstable clinical condition at the transferring hospital. The proportion of transferred medical-service patients who died was 9.4 percent, which was significantly higher than the proportion of medical-service patients who were not transferred (3.8 percent, P less than 0.01). There was no significant difference in the proportion of deaths on the surgical service between patients who were transferred and those who were not (1.5 vs. 2.4 percent). We conclude that patients are transferred to public hospitals predominantly for economic reasons, in spite of the fact that many of them are in an unstable condition at the time of transfer.

Adult↗