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Biomedical subjects

D G Pennington

Publications and source records attributed to D G Pennington.

At least 37 records · Page 2Linked to original sources
PubMed1995

Free flaps in the management of intrathoracic sepsis.

Experience with 5 free flaps, 1 TRAM and 4 latissimus dorsi flaps, transferred intrathoracically for the management of chronic sepsis is described. Healing and elimination of sepsis was achieved in all cases despite the infection being resistant to all previous more traditional forms of treatment including thoracoplasty. The results were achieved with minimal morbidity and argue for the early consideration of free flaps in the management of chronic intrathoracic sepsis in appropriate circumstances. A review of the limited available literature concerning this topic is presented.

Adult↗
PubMed1994

Risk stratification in patients bridged to cardiac transplantation.

Patient selection is considered one of the most important factors influencing success in bridge to transplant procedures. However, to date it has been difficult to identify predictors of mortality in this population using univariate or multivariate analysis. In 1988, we developed a scoring system using 21 clinical variables that could be calculated rapidly at the bedside while evaluating potential candidates. Points were designated to these variables using a scale of 1 to 3, 1 having the least adverse effect on survival and 3 the most. Patients received a value of 0 for each variable that did not apply. This scoring system was used in a retrospective analysis for 15 bridge to transplant patients. The results showed a significant difference (p < 0.003) between the 8 survivors (mean score, 5.75 +/- 2.19) and the 7 nonsurvivors (mean score, 11.71 +/- 3.45). Since 1989, we have prospectively calculated the scores in an additional 27 patients. Based on the score, all 42 patients were divided into three groups: group I had scores of 1 to 5; group II, 6 to 10; and group III, 11 to 16. The mean score for group I (16 patients) was 3.69 +/- 1.25. All group I patients survived. Group II patients (n = 15) had a mean score of 7.87 +/- 1.36 and a survival rate of 53%. The mean score for group III (n = 11) was 13 +/- 1.73. Thirty-six percent of these patients survived. Comparison of survival and mean scores among the three groups was statistically significant (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Tricuspid valve replacement after orthotopic heart transplantation.

Atrioventricular valvular regurgitation is a known complication after cardiac transplantation. In this communication, we describe a case of progressively severe tricuspid insufficiency that ultimately necessitated tricuspid valve replacement. The patient has done well clinically since valve replacement, and a postoperative cardiac catheterization demonstrated normal right heart hemodynamics. A discussion of proposed causes and a review of the literature are provided.

Cardiomyopathies↗
PubMed1994

Microvascular augmentation of the super-thin occipito-cervico-dorsal flap.

The super-thin flap technique was first devised in China. Flaps thinned by this technique are especially useful in the neck, face or hands of patients with extensive burn scarring, where the combination of thinness and suppleness is needed. However, some of these radically thinned flaps may suffer from superficial or full thickness necrosis due to the unpredictability of survival of the super-thinned area. In this paper, we present a technique of microvascular augmentation of the blood supply of the thinned flap, an example of so-called "supercharging".

Adult↗
PubMed1994

Vascular complications from intraaortic balloons: risk analysis.

PURPOSE: The purpose of this study was to assess the incidence of and predictors for vascular complications in patients who required perioperative intraaortic balloon pump (IABP) support. METHODS: Data from 580 patients collected with a retrospective review were statistically analyzed with 25 perioperative parameters, and significant variables were evaluated with multivariate analysis. These data were also statistically compared with data from a 1983 study from our institution. RESULTS: Vascular complications occurred in 72 patients (12.4%). The three aortic perforations were fatal. Ipsilateral leg ischemia occurred in 69 patients. Of these, ischemia was resolved in 82% of patients by IABP removal (21), thrombectomy (21), vascular repair (13), fasciotomy (2), or without intervention (2). Six patients died with the intraaortic balloon in place. Four patients required amputation for ischemia, but all survived. CONCLUSIONS: Vascular complications were not predictive of operative death (p = 0.26). Risk analyses with 25 perioperative parameters revealed that history of peripheral vascular disease, female sex, history of smoking, and postoperative insertion were independent predictors of vascular complications. However, most risk for vascular complications cannot be explained by these factors because of a low R2 value. Compared with the results of our 1983 study, the incidence of IABP-related complications has not changed, but the severity of complications has decreased significantly, and IABP-induced death has decreased significantly.

Adult↗
PubMed1994

Reinfusion potassium blood cardioplegia versus cold blood reinfusion alone in elective revascularization.

The purpose of this study was to determine if the addition of potassium to reinfusion cold blood cardioplegia (CBC) offers an advantage over cold blood alone. Forty patients matched for age, left ventricular function, extent of coronary disease and number of vessels bypassed were prospectively randomized. Each patient received an initial dose of CBC (10 cc/kg) with potassium. Group I patients (n = 23) received subsequent infusions of CBC (5 cc/kg) containing potassium while Group II patients (n = 17) received cold blood only. The cross-clamp time, mean infusate volume and temperature were not significantly different in the two groups. Following reperfusion, the cardiac index and the CPK isoenzyme release at 0.5, 1, 8, and 12 h after cross-clamp release were not significantly different between the groups. The postoperative appearance of new Q-waves, inotropic agent requirement, and reversal of the lactate dehydrogenase (LDH) isoenzyme ratio were also not significantly different in the two groups. The study demonstrated that following initial arrest with potassium, cold blood is equally as effective as potassium blood cardioplegia in protecting the ischemic myocardium.

Aged↗
PubMed1994

Mechanical circulatory support of the failing heart.

Over the past 30 years, there have been significant pharmacological and technological advances in the treatment of cardiogenic shock. Although most patients who develop cardiogenic shock can be effectively treated with conventional therapy, including inotropic and vasodilating drugs and intra-aortic balloon pumps, a significant number of patients have ventricular failure that is refractory to conventional therapy. For these patients, the prognosis is poor unless the deleterious effects of cardiogenic shock can be reversed. For some, cardiac revascularization or the repair of mechanical defects reverses the hemodynamic deterioration. However, there are subgroups of patients in whom an advanced form of mechanical circulatory support is necessary for myocardial recovery or in whom recovery will never occur, but who may be candidates for cardiac transplantation.

Heart Failure↗
PubMed1994

Implantation technique for the Novacor left ventricular assist system.

The Novacor left ventricular assist system (Baxter Healthcare Corp., Novacor Div., Oakland, Calif.) is currently undergoing clinical investigation as a bridge to cardiac transplantation. The original animal and clinical protocols recommended placement of the pump/energy converter within the peritoneal space. During preclinical cadaver fitting trials, we determined that it might be difficult to place this device in the peritoneal cavity of tall, slender patients, patients having a small muscular abdomen, and many women. We were also concerned that peritoneal placement would increase the risk and severity of infection and that abdominal organs might be injured by direct contact with the pump. In studies in cadavers, we therefore developed a technique using preperitoneal placement of the pump/energy converter. This technique has now been used successfully in more than 200 patients. A detailed description of this insertion technique is presented to facilitate its current use for the implantation of temporary devices and to plan for the implantation of permanent systems.

Assisted Circulation↗
PubMed1994

Noncardiac operations in patients supported with mechanical circulatory support devices.

BACKGROUND: Recent advances in technology as well as refinements of patient selection criteria have improved results of ventricular assistance in patients with end-stage heart disease. With a "normal" cardiac output and the resultant improvement in end-organ perfusion, some patients revert to normal or near normal physiology. Seven patients supported with cardiac assist devices who have undergone general surgical, nonassist device related procedures with the assist device in place are presented. STUDY DESIGN: This is a historical review of seven cases. RESULTS: The surgical procedures included three cholecystectomies, one dialysis catheter placement, and one thoracoscopy. Six patients had Thoratec ventricular assist devices (Thoratec Laboratories Corp., Berkeley, CA) and one was supported with a Jarvik (Symbion, Inc., Tempe, AZ) total artificial heart. In one patient, postcholecystectomy bleeding was the only complication that may have been directly attributable to having an assist device in place. Four patients underwent successful transplantation and three patients died, two during support and one after transplantation. CONCLUSIONS: As heart transplant waiting lists become longer and when permanent ventricular assist devices become available, an increasing number of patients on ventricular assistance will have noncardiac related pathology requiring operative intervention. In our experience, patients supported on mechanical assist devices tolerated these procedures well.

Adult↗
PubMed1994

Circulatory assist devices in congestive heart failure.

This article discusses the use of mechanical circulatory assist devices to support patients who have developed heart failure that has become refractory to more conventional treatment. Included is a description of the various devices available, the respective advantages and disadvantages of each, and a general discussion of the indications for mechanical circulatory support.

Equipment Design↗
PubMed1994

Working heart model of heterotopic heart-lung transplantation in rats.

A technique for a working heart model of heterotopic heart-lung transplantation is described. The donor aorta and left pulmonary artery are anastomosed to the recipient's abdominal aorta in an end-to-side fashion. Arterial blood from the recipient's abdominal aorta enters the donor left heart via the donor left lung and is ejected into the donor ascending aorta by the transplanted left ventricle. With this model, the donor left ventricle performs work comparable to that of the native heart without hypoxia. This model is easily reproducible and can be applied to various studies, including long-term assessments of cardiac remodeling, long-term efficacy of cardiac preservation, and posttransplantation ventricular performance under more physiologic conditions.

Animals↗
PubMed1994

Eight years' experience with bridging to cardiac transplantation.

Although bridging to cardiac transplantation has become a therapeutic option for transplant candidates whose condition deteriorates while they are awaiting a donor heart, short-term efficacy has not been proved and long-term survival has not been reported. We retrospectively reviewed data on 44 patients who had circulatory assist devices placed as a bridge to transplantation between May 1985 and April 1993. The 35 male and nine female patients ranged in age from 12 to 65 years (mean 43.8 years). Thirty-one patients were supported with 32 Thoratec (18 left ventricular, 14 biventricular), 11 Novacor, and two Jarvik J-7-70 devices. The duration of device support was from 4 hours to 440 days (mean 45.5 days). Fifteen patients did not receive a donor organ because of infection (ten patients), renal failure (five patients), bleeding (nine patients), cerebrovascular accident (three patients), ventricular fibrillation (one patient), and right heart failure (one patient), and all died. Two patients were weaned from support and survived without transplantation. Twenty-seven patients underwent transplantation, and 26 survived (96%). Overall survival was 64% (28/44). Duration of survival ranged from 2 to 96 months (mean 35 months). Among the 28 hospital survivors, there were four late deaths (all transplant recipients) at 3, 6, 14, and 68 months. Posttransplantation actuarial survivals at 1, 5, and 8 years are 88%, 83%, and 66%. Twenty-three of the 24 patients presently alive are in New York Heart Association functional class I. These data demonstrate the short- and long-term efficacy of bridging to transplantation with circulatory support devices. The excellent survival and full functional recovery of patients undergoing transplantation ensure that donor organs are not being "wasted" on the sickest patients.

Actuarial Analysis↗
PubMed1993

Circulatory support in infants and children.

Although the last decade has brought dramatic improvement in patient selection and postoperative management of adults and children undergoing advanced mechanical circulatory support, technological advances have been largely limited to the adult population. Intraaortic balloon pumps are technically feasible, but their efficacy has been questioned and their use has been limited in children. Over the last decade, extracorporeal membrane oxygenation has become the most commonly used method of mechanical circulatory support in children who have severe cardiac failure after cardiac operations. Additionally, a small number of infants and children have been supported with extracorporeal membrane oxygenation as a bridge to cardiac transplantation or as temporary support during reversible myocardial failure due to lesions such as viral myocarditis. More recently, a small number of pediatric patients have been supported with centrifugal and pneumatic devices, particularly after cardiac operations. Surprisingly, many of these patients did well with left ventricular support only. The overall children's survival rates in the myocardial recovery group are better than those in adults. However, current pediatric devices do not provide support for greater than a few weeks, making bridging to transplantation less feasible than in adults.

Assisted Circulation↗
PubMed1993

Microvascular augmentation of the blood supply of the contralateral side of the free transverse rectus abdominis musculocutaneous flap.

The free transverse rectus abdominis musculocutaneous (TRAM) flap is a recognized, reliable method of breast reconstruction after mastectomy. However, blood supply to the contralateral side of both the free and pedicled TRAM flap, especially in zone four, is often precarious. In patients with previous midline abdominal scars or with significant rectus divarication, both zones three and four are at risk of necrosis. Various techniques have been described to improve the reliability of the blood supply to the contralateral tissue in the pedicled TRAM flap, including prior delay and microvascular supplementation. We describe a new technique for augmentation of the blood supply of the contralateral side by microvascular anastomosis of the distal end of the ipsilateral deep inferior epigastric vessels to a contralateral periumbilical perforator of the opposite side. This technique produces reliable survival of contralateral tissue in zones three and four, even in the presence of midline scars, with minimal damage to the contralateral rectus muscle. The technique is also beneficial where large bulk of tissue is needed, such as in radical mastectomy patients, or when abdominal tissue is thin but the normal breast is large. Five patients in a series of 50 free TRAM flaps have been treated with the technique and the results are compared with other techniques.

Abdominal Muscles↗