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Biomedical subjects

B F Akl

Publications and source records attributed to B F Akl.

At least 19 recordsLinked to original sources
PubMed1999

A comparison of manual and mechanical ventilation during pediatric transport.

OBJECTIVE: To compare the amount of variability in ventilation during intrahospital transport of intubated pediatric patients ventilated either manually or with a transport ventilator. DESIGN: Prospective, randomized study. SETTING: Tertiary, multidisciplinary, pediatric intensive care unit. PATIENTS: Forty-nine pediatric postoperative heart patients who required transport while still intubated. INTERVENTIONS: Patients were randomized to receive either manual ventilation during transport or ventilation by a portable mechanical ventilator. Baseline ventilatory and hemodynamic parameters were recorded before and during transport. Before and after arterial blood gases were also obtained. All other aspects of care were identical. MEASUREMENTS AND MAIN RESULTS: There was a statistically significant greater amount of variation in ventilation during transport with manual technique as opposed to the mechanical ventilator. A Student's t-test on pre- to post-blood gas differences showed a significantly lower PetCO2 (p = .02) in the manually ventilated patients when compared with the mechanically ventilated patients. Values for PCO2 were higher, but only marginally significant (p = .08). Repeated measures analysis of variance using these same pre- and post blood gas values confirmed the significant decrease in PetCO2 (p = .05). Minute to minute variation in PetCO2 during transport was greater and the mean values significantly lower in the manually ventilated group (p < .05). Hemodynamic data were remarkably stable when examined both before and after transport and on a minute to minute basis during transport. CONCLUSIONS: Manual ventilation during intrahospital transport results in greater fluctuation of ventilatory parameters from an established baseline than does use of a transport ventilator. No clinically significant changes in status occurred during the brief period of transport studied.

Adolescent↗
PubMed1996

Pediatric cardiopulmonary bypass: a review of current practice.

Devices and techniques used for pediatric cardiopulmonary bypass are ever changing. There are frequently reports in the literature about new techniques and new devices. Periodic surveys are helpful because they reveal the actual extent to which these techniques and devices are applied to clinical practice. Advances in research are bringing about a better understanding of the intricate aspects of CPB and the effects of CPB on pediatric patients. There appears to be a trend from widely divergent approaches to CPB for pediatric patients to more uniformity in practice. For example, the use of membrane oxygenation and arterial line filtration has become universal, and there is an increase in the use of all types of safety devices. Techniques reported in the medical literature at the beginning of the decade, such as, the use of modified ultrafiltration, the use of centrifugal cell washers to process packed red blood cells before adding them to the prime, and the use of the antifibrinolytic drug, aprotinin, have become part of practice at a large number of pediatric heart centers. Periodic surveys are useful, as they provide a measurement of current practice. They also provide a historical record of the advances in the field.

Antifibrinolytic Agents↗
PubMed1995

Surgical repair of an anterior mitral subvalvular aneurysm.

An individual with a ruptured congenital subvalvular aneurysm is presented. The anterior location in the mitral annulus compromised the intervalvular fibrosa shared by the aortic valve. Aortic and mitral valve replacement were required to obliterate the resulting fistula between the left ventricle and left atrium.

Adult↗
PubMed1995

Bacterial wound colonization after broad-spectrum versus narrow-spectrum antibiotics.

Broad-spectrum versus narrow-spectrum antibiotic prophylaxis for patients who undergo cardiac operations is variously advocated to reduce the incidence of all infections or, conversely, to prevent resistant superinfections. Previous studies of prophylaxis have shown a reduction in the incidence of staphylococcal infections with some increased resistance. We studied preoperative and postoperative wound colonization as a surrogate for infection. Among 78 patients undergoing cardiac procedures, the type of prophylaxis was allocated as follows: narrow-spectrum (nafcillin), 24 patients; midspectrum (cephapirin), 26 patients; and broad-spectrum (ceftriaxone), 28 patients. Seventeen patients who underwent other procedures received no antibiotics and served as controls. Cultures of the operative site were done preoperatively, and 3 and 6 days postoperatively. The incidence of preoperative skin colonization with staphylococci was identical (95%) in all groups. Postoperatively, more patients receiving nafcillin (48%) were culture-negative for all organisms than were either of the other groups receiving antibiotics (27% and 22%) (p < 0.05). Gram-negative bacilli were infrequent colonizers and neither did the incidence of infection with these organisms increase nor did resistance develop in any group. The infection rates were not different among the treatment groups. Thus, a narrow-spectrum antistaphylococcal penicillin may offer an advantage in terms of both prophylaxis for cardiac operations and hospital costs.

Bacteria↗
PubMed1995

Paediatric perfusion practice in North America: an update.

In August 1994, an updated survey questionnaire was mailed to each paediatric open-heart surgery programme in North America as a follow-up to the 1989 paediatric survey. The survey requested demographic data, equipment selection criteria and specific perfusion techniques for paediatric patients. The earlier survey revealed a wide range of clinical practice. Data from the recent survey were compared with the 1989 survey to identify current programme demographics and trends in equipment use and techniques. Responses were received from 125 hospitals (110 active programmes and 15 programmes that do not perform paediatric open-heart surgery) for a response rate of 74%. Of the 110 active centres, 77 perform both adult and paediatric cardiac surgery, and 33 perform paediatric surgery exclusively. Forty-three centres reported that they perform paediatric cardiac transplantation, an increase from 35 centres in 1989. Total caseload increased by more than 8% per year from 1988 to 1994. In 1994, 18% of the patients were operated upon during the first month of life (versus 15% in 1989), and 46% were operated on during the first year of life (versus 45% in 1989). While the 1989 survey was characterized by a high degree of heterogeneity in equipment and techniques, the recent survey reveals a trend toward homogeneity among respondents. The use of membrane oxygenation and arterial line filtration has become universal, and there was an increase in the use of all types of safety devices in the cardiopulmonary bypass circuit.

Adolescent↗
PubMed1994

Alternative method of ultrafiltration after cardiopulmonary bypass.

A revised circuit design for modified ultrafiltration is presented rendering the technique more convenient for use after cardiopulmonary bypass when blood cardioplegia is used. The procedure employs a hollow-fiber ultrafiltration device attached to the cardioplegia circuit. A bubble trap, heat exchanger, and a pressure monitor are incorporated as safety features. The technique has been used in 80 patients (30 pediatric and 50 adult) and has been associated with relevant increases in colloid osmotic pressure and hematocrit.

Adult↗
PubMed1994

Ascending aorta to right pulmonary artery interposition shunt in critically ill infants.

In spite of a trend toward earlier complete repair, some neonates and infants with complex cyanotic heart disease continue to require interim palliation with systemic-to-pulmonary artery shunts. A variety of shunt procedures have been proposed, each with inherent advantages and disadvantages. We have found a prosthetic interposition shunt between the ascending aorta and right pulmonary artery (AA-RPA) to be effective in very young infants with small vessels. Over a 15-year period, 51 patients, mean weight 3.33 kg and mean age 59 days, underwent this procedure with a 13% perioperative mortality and a 78% 2-year overall shunt patency rate. We conclude that the AA-RPA interposition shunt is a safe, effective procedure in these infants.

Aorta↗
PubMed1993

A reliable bridge to cardiac transplantation: the TCI left ventricular assist device.

The Thermo Cardiosystems (TCI) HeartMate, a pneumatically driven, implantable left ventricular assist device, was designed for long-term support of the failing heart. Between February 1990 and August 1992, the HeartMate was implanted in 11 heart transplant candidates because of profound deterioration of left ventricular function. Patients had a mean cardiac index of 1.6 L.min-1 x m-2 and a mean pulmonary capillary wedge pressure of 33 mm Hg despite maximal pharmacologic support with at least three inotropic medications. In addition, 5 patients were being supported with an intraaortic balloon pump. Nine patients were bridged successfully to cardiac transplantation. The mean cardiac index after implantation of the left ventricular assist device was 3.2 L.min-1 x m-2. Support ranged from 2 to 143 days (mean duration, 60 days). One patient died early of low output secondary to right heart failure, and a second died of air embolism, which occurred intraoperatively. All surviving patients became fully ambulatory. There were no thromboembolic complications during a total of 658 patient-days of support on a regimen of only 80 mg of aspirin daily. The 9 bridged patients are currently alive 4 to 34 months after transplantation. The TCI HeartMate provides safe and effective hemodynamic support with low risk of complications and virtual freedom from thromboembolism on a regimen of minimal anticoagulation.

Adult↗
PubMed1991

Traumatic rupture of the interventricular septum and tricuspid valve: case report.

Cardiac injury following blunt trauma is an important cause of morbidity and mortality and is often unsuspected. Isolated chamber rupture and valvular injury are infrequent but recognized consequences of nonpenetrating trauma. This report describes a patient who developed a perimembranous ventricular septal defect and disruption of the septal leaflet of the tricuspid valve as a consequence of blunt trauma. Diagnosis and management of traumatic ventricular septal rupture are discussed.

Accidents, Traffic↗
PubMed1990

Coronary artery bypass surgery: emerging trends in mortality.

In a consecutive series of 4,697 patients undergoing coronary artery bypass surgery, these risk factors were found to be significant for increased postoperative mortality: age greater than 70, female sex, unstable angina, prior myocardial infarction, hypertension, diabetes mellitus, and ejection fraction less than .40. A comparison by year (1980-1988) revealed a steadily increasing incidence of these risk factors. Future analysis of coronary artery bypass mortality should include risk-factor stratification.

Aged↗
PubMed1988

Arteriovenous and capillary hemangiomas of the interventricular septum.

The case of a patient with two extremely unusual types of hemangioma is presented. The arteriovenous and capillary hemangiomas of the interventricular septum were discovered on coronary angiography performed for chest pain. Echocardiography confirmed the diagnosis. Successful surgical excision was performed.

Adult↗
PubMed1987

Observations on flow characteristics of passive external aortic shunts.

Extraluminal heparin-bonded shunts have been recommended to support the distal circulation and decompress the proximal vascular bed during procedures that require interruption of flow through the thoracic aorta. Shunts that originate in either the left ventricle or the proximal aorta are generally viewed as hemodynamically similar, despite incomplete documentation of their flow characteristics. The present study was conducted to further define these hemodynamic properties. Identical extraluminal shunts were placed from the left ventricular apex and aortic arch to the distal thoracic aorta in mongrel dogs. Simultaneous pressure and Doppler flow velocities were recorded in the carotid and femoral arteries. Computer-enhanced composite waveforms were used to assist data analysis. When compared to ventricular cannulation, aortic cannulation provided improved proximal decompression and increased mean distal flow. In addition, significant diastolic flow reversal was recorded in the distal circulation when ventricular cannulation was employed. On the other hand, ventricular cannulation was associated with the preservation of pulsatile flow, whereas flow generated by aortic cannulation was linear. It is concluded that extraluminal shunts that originate in the left ventricle and the proximal aorta have distinct hemodynamic properties. These differences may be clinically important in specific situations.

Animals↗
PubMed1986

Lung cancer--current concepts and controversies.

The recent literature contains a variety of controversial management alternatives for patients with pulmonary malignancy that affect all aspects of the lung cancer problem. Revisions in the classification system have been advanced in which the prognostic implications of specific ultrastructural and histochemical information are acknowledged. Computed tomography and, to a lesser extent, nuclide scanning have revolutionized the staging process, but limitations in these procedures are emerging. Improved survival following aggressive surgical treatment has challenged the adequacy of the standard staging system. The palliative role of radiotherapy is becoming more widely appreciated. Results of immunotherapy are equivocal and gains from chemotherapy are modest. Combinations of treatment modalities will require further documentation before they can be recommended with confidence.

Antineoplastic Agents↗
PubMed1985

Enterobacter mediastinitis following cardiac surgery.

Eight cases of sternal/mediastinal infection due to Enterobacter species were seen in postoperative cardiac patients during 1980 to 1981. The attack rate was 14.5% (8/55), compared to 3.7% (2/54) for an identical period in 1979 to 1980 (p less than 0.05). Cases varied in severity from fulminant, acute bacteremic infections (one death) to less severe wound infection. Late complications or recurrences were not seen. There was a hospital-wide increase, relative to all other gram-negative bacillary isolates, in Enterobacter laboratory isolations, but no increased rate of infection in any other specific surgical condition. No personnel, materials, or techniques were associated with the outbreak, and all but two environmental cultures were negative. Case-control analysis suggested that surgical complications and prophylactic cephalosporins were associated with infection. Prospectively, an additional 85 cardiac surgery patients had increased Enterobacter skin/wound colonization following perioperative prophylaxis with cephalosporin antibiotics. After introduction of barrier isolation and restriction of contacts no further mediastinitis occurred in 100 subsequent cardiac surgery patients. This study indicates that Enterobacter may be major pathogens causing post-cardiac-surgery infection not prevented by cephalosporin prophylaxis.

Cardiac Surgical Procedures↗