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Biomedical subjects

D Amar

Publications and source records attributed to D Amar.

50 records · Page 3Linked to original sources
PubMed1991

An alternative oxygen delivery system for infants and children in the post-anaesthesia care unit.

This randomized controlled trial compared the compliance of a blow-by oxygen method with the standard face mask by children recovering from anaesthesia. The rate at which a face mask was rejected when applied to infants and children in PACU was compared with that of a proposed "hose" method. The efficacy of the "hose" as a method of oxygen supplementation in children at low and high risk for developing postoperative hypoxaemia was also compared with the face mask. Using a Nellcor N-200 pulse oximeter, 66 infants and children (mean age 2.3 yr, range 2 mo-6 yr) were continuously monitored for 30 min upon arrival in the PACU. Patients were randomized to receive oxygen supplementation with either the face mask or the proposed "hose" method. The results showed a greater than 80 per cent rejection of the face mask in contrast to 100 per cent compliance with the "hose" method. The SaO2 measurements following 5, 15 and 30 min of O2 supplementation with the hose were all significantly higher than the SaO2 measurements obtained on room air upon arrival to the PACU. Patients with pre-existing cardiopulmonary disease had a 20 per cent incidence of arterial oxygen desaturation upon arrival to the PACU versus 2.1 per cent of patients with no pre-existing disease. It is concluded that the "hose" is associated with high patient compliance and is effective in the PACU in increasing the SaO2 in children at low or high risk of developing postoperative hypoxaemia.

Anesthesia Recovery Period↗
PubMed1991

Effects of labetalol on perioperative stress markers and isoflurane requirements.

We have studied the effect of labetalol on anaesthetic requirements, cardiac and humoral responses in 16 healthy women during elective abdominal surgery. The experimental group (n = 8) received increments of i.v. labetalol 0.15-0.3 mg kg-1 to reduce mean arterial pressure (MAP) by 15% from values obtained before anaesthesia. All patients received thiopentone 6 mg kg-1 and anaesthesia was maintained with isoflurane and nitrous oxide. In the placebo group, tracheal intubation provoked a 33% increase in heart rate (HR) and a 52% increase in MAP (P less than 0.001 vs baseline for both). In contrast, pretreatment with labetalol resulted in a 7.3% increase in HR and a 21.3% increase in MAP (P less than 0.05 vs baseline for MAP). Two patients treated with labetalol had a reduction in MAP to 50-60 mm Hg during surgery. After tracheal extubation, the labetalol group had a significantly slower HR than the placebo group (P less than 0.05). The cardiovascular response to tracheal intubation was associated with an increase in plasma noradrenaline concentration in both groups. Labetalol did not affect isoflurane requirements, plasma concentrations of adrenaline, cortisol and aldosterone or arterial PO2, but prevented the decrease in plasma concentration of potassium which occurred in placebo treated patients (P less than 0.05) in early recovery. We conclude that preanaesthetic administration of labetalol attenuated the perioperative hypertensive and tachycardic responses, but was accompanied by intraoperative hypotension when given in doses greater than 0.5 mg kg-1, despite an increase in plasma noradrenaline concentrations.

Abdomen↗
PubMed1991

Extradural block in obstetric patients: review of experience with gravity administration.

Charts of 2284 obstetric patients who received extradural block with gravity administration of local anaesthetic were evaluated retrospectively. Despite a 1.3% incidence of vascular puncture and a 1.8% incidence of dural puncture, accidental intravascular or intrathecal injection of local anaesthetic did not occur. We propose that this method may be safer than the traditional "injection by needle" technique, and has a high degree of "visualization" of the otherwise "blind" extradural block procedure.

Anesthesia, Epidural↗
PubMed1989

Fluorescent light interferes with pulse oximetry.

Arterial oxygen saturation (SaO2) values displayed on the pulse oximeter dropped dramatically in 3 children undergoing neurosurgical procedures when a hand-held fluorescent light was used to observe the patients. Pulse rates were unchanged on both the electrocardiograph and pulse oximeter. Electromagnetic interference was excluded as the cause of desaturation. A great deal of energy was emitted by the hand-held light in the 660-nm region, which is one of the wavelengths used by the oximeter. False readings of pulse rate and SaO2 values caused by ambient light could be avoided if oximeter probes were manufactured of black opaque material that does not transmit light or enclosed in an opaque plastic housing.

Child, Preschool↗
PubMed1989

Anaphylactoid reactions to protamine: an often lethal complication in insulin-dependent diabetic patients undergoing vascular surgery.

Protamine is used routinely at our institution during arterial surgery to reverse the anticoagulant effect of heparin. Adverse fatal reactions to protamine are generally believed to be rare. However, major anaphylactoid reactions occurred in 11 of the last 1150 patients receiving this drug at our institution. Nine of these reactions occurred in 325 insulin-dependent diabetic patients (incidence, 3%), whereas only two occurred in the 825 patients not receiving insulin (incidence, 0.2%) (p less than 0.001). Ten of these reactions occurred within 10 minutes of protamine administration (15 to 35 mg), whereas one reaction occurred immediately after administration of a 5 mg test dose of protamine. Systolic blood pressure fell below 60 mm Hg in all of the 11 patients, and three patients had to be resuscitated with closed-chest massage. Initial treatment with epinephrine and steroids was successful in seven cases. Four patients required further resuscitative measures, including closed-chest massage. However, one of the patients died as a result of ventricular fibrillation resistant to treatment. Ten of the 11 patients, including the patient who died, had significant preexisting cardiac disease; six of the surviving 10 patients (60%) had perioperative myocardial infarctions and three died. Thus the total mortality rate was 36% (4/11). These data support the implication that neutral protamine Hagedorn (NPH) insulin produces an adverse reaction through immunologic presensitization of the patient. These data also show that, in the older vascular surgery population with a high incidence of significant cardiac disease, protamine reactions can be potentially lethal. Thus routine use of protamine should be avoided in diabetic patients receiving insulin.

Aged↗
PubMedDate not supplied

Epidural analgesia for labor and delivery in a patient with von Willebrand's disease.

Patients with histories of bleeding disorders may still benefit from regional anesthetic techniques. The decision to perform the block should be individualized, based on coagulation tests. The authors describe a patient with von Willebrand's disease in whom pregnancy itself improved factor VIII activity, enabling performance of an epidural block for labor and delivery.

Adult↗