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Biomedical subjects

F G Estafanous

Publications and source records attributed to F G Estafanous.

At least 55 records · Page 3Linked to original sources
PubMed1986

Cardiovascular effects of non-depolarizing neuromuscular blockers in patients with coronary artery disease.

To compare haemodynamic responses associated with equipotent doses of muscle relaxants and high dose fentanyl (50 micrograms X kg-1), 40 non-hypertensive patients who were receiving beta adrenergic and calcium channel blocker therapy and undergoing coronary bypass surgery were randomized to four study groups receiving the following: (1) atracurium: 0.4 mg X kg-1, (2) pancuronium: 0.12 mg X kg-1, (3) vecuronium: 0.12 mg X kg-1, or (4) pancuronium-metocurine mixture: (0.4 mg + 1.6 mg X ml-1):1 ml/10 kg. Neuromuscular blockers were injected with fetanyl at induction. Haemodynamics were recorded with the patients awake (baseline), at two minutes post-induction, and at two and five minutes after intubation. Pancuronium was the only drug associated with significant increases in HR; no other significant changes occurred within each group when compared to their respective baseline haemodynamics. HR increased more after induction with pancuronium when compared to atracurium (23 vs. 4 per cent, p less than 0.05) and to vecuronium (23 vs. 2 per cent, p less than 0.05), and when compared to vecuronium after intubation (29 vs. 7 per cent, p less than 0.05). The pancuronium-metocurine mixture caused tachycardia which was less than, though not significantly different than with pancuronium; however, HR returned to baseline by five minutes with the mixture, but remained elevated with pancuronium (3 vs. 18 per cent, p less than 0.05). SVR fell more on induction with atracurium when compared to vecuronium (-18 vs. 1 per cent, p less than 0.05). These changes in HR or SVR were not accompanied by ECG signs of ischaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1985

Comparison of the effects of 15 and 60 micrograms/kg fentanyl used for induction of anesthesia in patients with coronary artery disease.

We compared the effects of 15 and 60 micrograms/kg fentanyl used for induction in 40 patients, 50-72 yr old, with coronary artery disease and mildly impaired ventricular contractility. Morphine (0.1 mg/kg) and scopolamine (0.4 mg) were used for premedication. Crystalloid (500 ml) was administered before induction, and nitroglycerin (0.3 micrograms X kg-1 X min-1) was infused during the study. Fentanyl, 15 or 60 micrograms/kg, was administered at a rate of 1.2 micrograms X kg-1 X sec-1. Pancuronium (0.04 mg/kg) and metocurine (0.16 mg/kg) were used for muscle relaxation. Data were collected 2 min before induction (baseline), before intubation (3 min), at 6 min, and at 13 min. Responses to 15 and 60 micrograms/kg were similar. At 3 min the heart rate (HR) in patients given 15 micrograms/kg increased by 6; whereas the HR in those given 60 micrograms/kg increased by 14 (P less than 0.01). Subsequent differences in HR were not significant. There were no dose-related differences in mean arterial pressure, cardiac index, central venous pressure, or pulmonary capillary wedge pressure. The EEG showed high-voltage low-frequency activity within 2 min in all patients. Arterial plasma fentanyl concentrations at 3 min averaged 25.9 +/- 3.8 ng/ml with 15 micrograms/kg and 89.9 +/- 15.2 ng/ml with 60 micrograms/kg. At 4 hr, plasma concentrations averaged 0.4 +/- 0.2 ng/ml and 3.6 +/- 0.7 ng/ml, respectively. We conclude that anesthesia for induction and intubation is achieved by the rapid administration of 15 micrograms/kg fentanyl and that 60 micrograms/kg has no substantially different effect on cardiovascular responses.

Aged↗
PubMed1984

Continuous S-vO2 measurement and oxygen transport patterns in cardiac surgery patients.

Twenty adult cardiac surgery patients with impaired ventricular function by contrast ventriculography at cardiac catheterization were monitored from before anesthesia until the time of extubation up to 12 h postoperatively. A thermodilution pulmonary artery catheter with fiberoptic channels for continuous measurement of mixed-venous oxygen saturation (S-vO2) by reflection oximetry was substituted for the usual catheter. The S-vO2 was recorded continuously along with blood pressure, cardiac filling pressures, and heart rate. Thermodilution cardiac output determinations were used to derive hemodynamic and oxygen transport indices. There was a consistently high and significant negative correlation (r = -.84) between S-vO2 and the percentage of oxygen extracted from blood. Thus, S-vO2 reflects oxygen extraction and continuous S-vO2 provides continuous quantification of global oxygen extraction. None of the other oxygen transport variables including cardiac index showed significant correlation with S-vO2. The oximetry system provides a continuous and reliable indication of mixed-venous blood oxygenation which is a continuous reflection of oxygen extraction.

Aged↗
PubMed1984

Pattern of hemodynamic alterations during coronary artery operations.

Twenty-four patients were studied to determine the relative importance of cardiac and peripheral factors in the hemodynamic changes associated with coronary artery operations. None had preoperative evidence of ventricular impairment. Anesthetic management was standardized for all. Sequential hemodynamic measurements revealed the following: (1) Five minutes following induction of anesthesia, all hemodynamic indices were stable except for an increase in heart rate (p less than 0.001). Sternotomy and pericardiectomy were followed by a drop in cardiac index (p less than 0.01) and systolic blood pressure (p less than 0.01). (2) Late during bypass, there was a significant, parallel reduction in both hematocrit and systemic vascular resistance (SVR) (p less than 0.001 and 0.01, respectively). (3) Five minutes after termination of bypass, cardiac output was markedly elevated (p less than 0.001) in association with a decrease in SVR (p less than 0.001), marked hemodilution (p less than 0.001), and tachycardia (p less than 0.001). (4) Following sternal closure, and despite the fact that the hematocrit was still reduced (p less than 0.001), there developed a trend of increased mean arterial pressure (MAP) and SVR with a reduction in cardiac index. These changes were further accentuated 1 hour postoperatively. The SVR was 33% higher than in the previous stage (p less than 0.01), whereas the high cardiac index recorded with initiation of bypass declined significantly to preoperative values. Throughout the studies, there was a strong correlation between alterations in hematocrit and changes in cardiac index and SVR. Blood pressure variations showed no correlation with changes in cardiac output but were significantly related to alterations of peripheral resistance. Sequential determinations of plasma renin activity and catecholamine levels showed no significant alterations in either. The alterations reported describe not only group averages but also the behavior of every patient investigated. The results suggest that in patients with normal or only mild left ventricular impairment, the major factor influencing arterial pressure variations during coronary artery operations and in the postoperative period was the change in peripheral resistance rather than alterations in cardiac output. In the treatment of hypotension under these conditions, one should take into account variations in peripheral vascular resistance and not depend solely on assumed changes in myocardial performance.

Aged↗
PubMed1983

Mechanism and frequency of brachial plexus injury in open-heart surgery: a prospective analysis.

A computer-assisted prospective analysis of 531 patients undergoing open-heart operations revealed that 26 patients (5%) sustained brachial plexus injury. In 22 of the 26 patients (85%), the lesion involved the lower trunk or C8-T1 nerve roots. Electromyograms confirmed the clinical impression in 13 patients. In 19 of the 26 patients (73%), the side on which the plexus lesion was found correlated with the side of internal jugular vein cannulation. Because of the anatomical proximity of the lower trunk to the internal jugular vein and the preponderance of lower trunk lesions, we postulate that traumatic cannulation may be a major mechanism of plexus injury. Thus, the resulting syndrome of pain, dysesthesias, and hand weakness may sometimes be preventable.

Adult↗
PubMed1982

Peripheral nervous system complications of coronary artery bypass graft surgery.

Among 421 patients undergoing coronary artery bypass graft surgery, 55 (13%) developed 63 new peripheral nervous system (PNS) complications postoperatively. Most common was a brachial radiculoplexopathy, which occurred in 23 patients. Of these, 21 involved lower trunk or medial cord fibers. In 17 there was a correlation between the site of jugular vein cannulation and the side affected, suggesting that needle trauma played a role. Stretching from chest wall retraction may have caused some cases. Other deficits included 13 saphenous, 8 common peroneal, and 5 ulnar mononeuropathies. Six patients had persistent singultus, suggesting phrenic nerve involvement. Unilateral vocal cord paralysis was found in 5. An isolated partial Horner syndrome and a facial neuropathy were also identified. Males were more likely to develop PNS complications. Hypothermia during surgery was associated with increased risk. Most PNS deficits were transient, and lasting disability was rare.

Adult↗
PubMed1982

Failure of positive end-expiratory pressure to decrease postoperative bleeding after cardiac surgery.

To determine whether the application of positive end-expiratory pressure (PEEP) in the postoperative period after cardiac operation would reduce postoperative blood loss, the number of transfusions required, or the rate of reoperation for bleeding, we conducted a prospective study of 83 patients who underwent elective coronary revascularization. These patients were randomly assigned to receive either PEEP (10 cm H2O) or no PEEP (zero end-expiratory pressure). All other aspects of their care were identical. There was no statistically significant reduction in the amount of bleeding in patients treated with PEEP at 8 or 24 hours postoperatively. There was no significant difference in hematocrit between the groups preoperatively or postoperatively. There was no statistically significant difference in the number of reexplorations for bleeding. Finally, there was no significant difference between the groups in the amount of blood administered. On the basis of our results, we conclude that the application of PEEP in the postoperative period of cardiac operation did not reduce the amount of blood loss, the need for reexploration for bleeding, or the blood requirements in this group of patients.

Cardiac Surgical Procedures↗
PubMed1982

Extravascular lung water values in patients undergoing coronary artery bypass surgery.

Using a commercially produced lung water computer, we measured extravascular thermal volume (ETVL) to study changes in extravascular lung water (EVLW) caused by coronary artery bypass surgery. The normal baseline ETVL before anesthesia was 5.47 +/- 1.67 (SD) ml/kg. ETVL was not significantly changed 2 h after surgery but was significantly lower (P less than 0.05) 24 h later in 9 patients. There was no relationship between P(A-a)O2/FIO2 ratios and values of ETV1.

Body Water↗