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Biomedical subjects

J S McLaughlin

Publications and source records attributed to J S McLaughlin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Extravascular fluid uptake during cardiopulmonary bypass in hypertensive dogs.

We investigated the effects of increases in central venous pressure (CVP) and carotid baroreceptor-induced vasodilation on the rate of extravascular fluid uptake during cardiopulmonary bypass in normotensive and Goldblatt hypertensive dogs. Carotid sinus baroreceptors were selectively perfused to control the level of vasodilation. Central venous pressure was controlled by changing the height of the venous outflow cannula. Extravascular fluid uptake was determined from the rate of change in reservoir volume. After 3 hours of bypass, total fluid accumulation was 56.11 +/- 14.16 mL/kg in normotensive dogs, significantly less than in hypertensive dogs (110.90 +/- 23.20 mL/kg) (p < 0.05). Raising CVP from 1 to 5 mm Hg increased the rate of extravascular fluid uptake in both normotensive (from 0.05 +/- 0.25 to 0.85 +/- 0.22 mL.kg-1.min-1; p < 0.05) and hypertensive dogs (from 0.68 +/- 0.28 to 2.57 +/- 0.46 mL.kg-1.min-1; p < 0.01)). At a constant CVP, baroreceptor-induced vasodilation increased the rate of extravascular fluid uptake in normotensive (from 0.25 +/- .15 to 0.81 +/- .22 mL.kg-1.min-1) and in hypertensive dogs (from 0.84 +/- .12 to 1.72 +/- .32 mL.kg-1.min-1; p < 0.05). Hypertensive dogs were more sensitive to changes in CVP and to baroreceptor-induced vasodilation. The results of this study imply that elevations in CVP or the use of vasodilators may lead to increased extravascular fluid uptake during bypass; this effect may be exacerbated in the hypertensive state.

Animals↗
PubMed1994

Hemodynamic effects of carbon dioxide insufflation during thoracoscopy.

As more complex thoracoscopic procedures are performed, adequate exposure becomes increasingly more important. The insufflation of CO2 has been demonstrated to aid in the compression of lung parenchyma and the effacement of subpleural lesions, and to act as a retractor when combined with changes in patient position. However, a recent study demonstrated that CO2 insufflation during thoracoscopy in the pig had adverse hemodynamic consequences. We prospectively studied 32 patients undergoing thoracoscopy to evaluate the effects of CO2 insufflation in the clinical setting. The end-tidal CO2 pressure, arterial oxygen saturation, mean arterial pressure, heart rate, and central venous pressure were monitored. Measurements were determined at baseline, at the initiation of one-lung ventilation, and at intrapleural pressures of 2 to 14 mm Hg. We found that the insufflation of CO2 of 2 to 14 mm Hg had no significant effect on the end-tidal CO2 pressure, arterial oxygen saturation, heart rate, or mean arterial pressure, but the central venous pressure did rise from 7.00 +/- 1.5 mm Hg to 17.30 +/- 2.53 mm Hg (p < 0.05). We conclude from this that the insufflation of CO2 during thoracoscopy does not have adverse hemodynamic effects in the clinical setting. Therefore, we propose that low-pressure (< 10 mm Hg) insufflation is a safe adjunct to the conduct of routine thoracoscopic surgical procedures.

Adult↗
PubMed1994

Efficacy and safety of thoracoscopy for diagnosis and treatment of intrathoracic disease: the University of Maryland experience.

Thoracoscopy has become an important tool in the diagnosis and management of intrathoracic disease. Between April 1991 and October 1992, 93 patients underwent thoracoscopy. Lung resection was performed on nineteen patients for diagnoses of interstitial lung disease and on seven patients for pulmonary nodules. Eleven patients underwent therapeutic lung resection for management of pneumothorax or air leaks. Sixteen patients underwent thoracoscopy for pleural disease. This was to diagnose mesothelioma (2), to lyse benign adhesions (2), to drain empyema (2), and to evacuate loculated pleural effusion (10) thoracoscopically. Nine patients underwent thoracoscopic staging for lung cancer. Thirteen patients underwent thoracoscopic staging for esophageal cancer as part of a prospective trial. Other indications for thoracoscopy included pericardiectomy (6), sympathectomy (2), and resection of mediastinal mass (4). Thoracoscopy is an excellent option for patients at high risk from standard thoracotomy and may allow procedures to be performed which would prevent the need for open thoracotomy, resulting in shorter hospital stay and less postoperative pain.

Aged↗
PubMed1993

Thoracoscopic lymph node staging for esophageal cancer.

Thoracoscopy allows evaluation of the mediastinum and assessment of the local spread of malignancy. Adjuvant therapy trials have shown some increased survival for esophageal cancer although morbidity is high. Preoperative staging may allow appropriate allocation of adjuvant therapy. Patients with esophageal cancer underwent computed tomographic scan, magnetic resonance imaging, and endoesophageal ultrasonography. Thoracoscopic staging was performed through the left chest with biopsy of American Thoracic Society level 5 and 6 and 8 and 9 lymph nodes. Resection at a separate sitting with complete intraoperative lymph node sampling was done. Fourteen patients underwent thoracoscopic lymph node staging. One procedure could not be completed because of adhesions. Of the 13 patients undergoing successful staging, all had correct thoracic lymph node staging confirmed at surgical exploration. Two patients with adenocarcinoma of the distal third/gastroesophageal junction were found at laparotomy to have positive celiac lymph nodes. Two patients who had lymph nodes positive at computed tomographic scan and magnetic resonance imaging were found to have negative lymph nodes at thoracoscopy and subsequent resection. Two patients were found to have pulmonary metastasis at thoracoscopy. Lymph node stage in esophageal carcinoma is an important prognostic indicator. Thoracoscopic lymph node staging provides accurate pre-resection staging information.

Adenocarcinoma↗
PubMed1993

The extracardiac total cavopulmonary connection for definitive conversion to the Fontan circulation: summary of early experience and results.

Between July 1991 and March 1993, five children (ages 2 to 6 years) with complex congenital heart disease have undergone a new operation for conversion to the Fontan circulation. This procedure combines a bidirectional Glenn shunt with an extracardiac lateral tunnel (ELT) to carry systemic venous return to the pulmonary arteries (PAs). The ELT was constructed so that the circumference consists of Gore-Tex (2/3) and lateral epicardial atrial wall (1/3). The ELT can be performed with all varieties of single ventricle physiology, as in our patients with tricuspid atresia (n = 3), dextrocardia (n = 1), and situs inversus with levocardia (n = 1). PA reconstruction was required in four patients. At follow-up from 1 to 20 months, all patients are in New York Heart Association Class I and in normal sinus rhythm. Postoperative catheterization has revealed low PA pressures (< or = 12 +/- 1 mmHg) and angiography has shown excellent ELT function with brisk flow into the PAs bilaterally. All patients maintain an O2 saturation > 94% on room air. The advantages of this new extracardiac modification of Fontan's operation are: (1) aortic cross-clamping is not usually required; (2) incorporation of lateral atrial wall in ELT allows for growth while permitting construction of a fenestration or adjustable atrial septal defect in high risk patients; (3) absence of atriotomy and intraatrial suture lines may decrease late risk of arrhythmias; (4) early or late baffle leaks cannot occur; (5) intraatrial obstruction from the baffle cannot occur; (6) coronary sinus remains in low pressure atrium; and (7) hydrodynamic benefits of the total cavopulmonary connection are preserved. We recommend this procedure for patients undergoing surgical conversion to the Fontan circulation.

Anastomosis, Surgical↗
PubMed1992

Chronic, traumatic pseudoaneurysm of the ascending aorta.

Rupture of the ascending aorta is lethal in virtually all cases. In the recent literature, fewer than 9 cases of chronic, traumatic pseudoaneurysm of the ascending aorta have been documented. Reported herein is such a case, discovered incidentally and repaired successfully under cardiopulmonary bypass using a graft prosthesis. Aortogram remains the diagnostic method of choice in these patients.

Adult↗
PubMed1992

Extracardiac total cavopulmonary connection.

We report the case of a 6-year-old child who underwent definitive conversion to the Fontan circulation using a newly conceived operative technique. This new procedure allows the operation to be performed as a totally extracardiac operation and is based on the hydrodynamic principles of the total cavopulmonary connection.

Anastomosis, Surgical↗
PubMed1991

Penetrating cardiac injuries.

One hundred nine penetrating cardiac injuries were reviewed: 49 gunshot wounds and 60 stab wounds. They were classified into four groups: group 1 (lifeless), 38; group 2 (agonal), 16; group 3 (shock), 33; and group 4 (stable), 22. Thirty-six patients in group 1 (94%) and 8 of 16 patients in group 2 (50%) underwent emergency room thoracotomy; 24 of 33 in group 3 (73%) and 20 of 22 (90%) underwent thoracotomy in the operating room. Twenty-one (38%) of 55 patients undergoing emergency room thoracotomy survived, whereas 47 (87%) of 54 patients undergoing operating room thoracotomy survived. Survival was 12 of 38 (31%) in group 1, 11 of 16 (69%) in group 2, 26 of 33 (79%) in group 3, and 18 of 22 (82%) in group 4 with an overall survival of 67 of 109 (61%). Gunshot wounds of the heart portend a worse prognosis than stab wounds. Survival of gunshot wounds was 20 of 49 (40%) compared with 47 survivors of 60 stab wounds (78%). Aggressive treatment, including emergency room thoracotomy, is justified for lifeless and deteriorating cardiac injury victims.

Adolescent↗
PubMed1990

Esophageal perforation: a therapeutic challenge.

The records of 64 patients with esophageal perforation treated since 1958 were reviewed. There were 19 cervical perforations, 44 thoracic perforations, and one abdominal perforation. Thirty-one perforations (48%) were due to injury from intraluminal causes. Twenty (31%) resulted from extraluminal causes: penetrating wounds, 11; blunt trauma, 3; and paraesophageal operations, 6. Eleven (17%) were spontaneous perforations, and two (3%) were caused by perforation of an esophageal malignancy. Ten (91%) of 11 patients with cervical perforations treated less than 24 hours after injury survived compared with 6 (75%) of 8 patients treated more than 24 hours after injury; hence 16 (84%) of the 19 patients in the cervical group survived. In the thoracic group, 19 patients were treated within 24 hours with 16 survivors (84%) compared with 25 patients treated beyond 24 hours with 12 survivors (48%); hence 28 (64%) of the 44 patients in the thoracic group survived. The patient with an abdominal perforation survived. Thirty patients underwent primary suture closure of the perforation, and 25 (83%) lived. Seventeen patients had drainage, and 10 (59%) lived. Total esophagectomy was performed in 9 patients, 7 (78%) of whom survived. Exclusion-diversion procedures were performed in 5 patients, and 1 (20%) survived.

Adult↗
PubMed1990

Facile retrograde cardioplegia: transatrial cannulation of the coronary sinus.

The benefits of coronary sinus (CS) cardioplegia are well known, yet CS cardioplegia is not used widely owing to the need for bicaval cannulation, snares, and an atriotomy. We designed and used in 225 consecutive patients a catheter containing a flexible removable stylet that, when shaped into a hockey-stick configuration, enabled blind intubation of the CS through a small pursestring in the right atrium, guided easily into the CS using a finger on the atrioventricular groove at the inferior vena cava. The CS was intubated in all patients; a pressure-limited balloon at the catheter tip was inflated after cross-clamping. An integral distal pressure line measured CS pressure. Catheters were placed distally within the great cardiac vein beyond the posterior interventricular vein; the position did not alter cooling: right ventricular free wall, septum, and left ventricular free wall temperatures were 7 degrees +/- 2 degrees, 8 degrees +/- 2 degrees, and 7 degrees +/- 2 degrees C, respectively, after an initial 10 mL/kg of blood cardioplegia. Transatrial CS cardioplegia was used in 45 aortic valve replacements, 22 mitral valve replacements, 4 triple-valve replacements, 6 congenital lesions, and 148 coronary revascularizations, including 40 redo operations. Atheromatous material was routinely flushed retrogradely from cut old vein grafts during revascularization; 70 revascularizations (47%) were performed urgently for acute infarction or jeopardized myocardium. No heart block or CS injury occurred, and inotrope use dropped to 10% of patients (from 38% in the previous 256 patients with antegrade blood cardioplegia). We conclude that the CS can be cannulated transatrially and that CS cardioplegia is more facile than antegrade cardioplegia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Carcinoma of the esophagus: a comparison of the results of transhiatal versus transthoracic resection.

The cases of 78 patients with primary esophageal carcinoma treated from 1977 to mid-1987 were retrospectively analyzed. Fifty-two of the patients underwent transthoracic esophagogastrectomy (TTE) and 26, transhiatal esophagectomy (THE). The two groups were statistically similar in preoperative characteristics except that more of the THE group had received chemotherapy; this group had relatively more tumors of the upper esophagus; and 20 (77%) of the THE group, compared with 50 (96%) of the TTE group, had tumors in stages III and IV. The incidence of major postoperative complications did not differ significantly between the two groups. There were five (19%) anastomotic leaks in the THE group, but only one led to a prolongation of hospital stay by more than 14 days, whereas all three (6%) of the leaks in the TTE group caused hospital stay to be prolonged several weeks. Overall morbidity was high: 75% (39/52) for the TTE patients and 85% (22/26) for the THE patients (p greater than 0.10). Hospital mortality was 6% (3/52) in the TTE group and 8% (2/26) in the THE patients (p greater than 0.10). There was no significant difference in actuarial survival either between the two groups as a whole or between those patients in each group who had stage III or IV tumors. We conclude that THE, among the types of patients for whom we used the procedure, provides long-term survival comparable with that provided by TTE without causing a significant increase in hospital mortality or morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1989

Postoperative conduction disturbances: a comparison of blood and crystalloid cardioplegia.

Conduction system disturbances after cardioplegia are well described. Our four-man group changed in mid-1987 from standard crystalloid cardioplegia (35 mEq/L of KCl) to blood cardioplegia (4 parts blood to 1 part cardioplegia) (18 mEq/L of KCl) based on experimental and clinical evidence that blood cardioplegia provides better myocardial protection. Shortly thereafter, we anecdotally noted increased conduction abnormalities. This prompted us to compare serially all patients undergoing coronary artery bypass grafting during 1987 for perioperative and late conduction system disturbances after either crystalloid or blood cardioplegia. Surgeons and techniques including topical cooling did not differ. Forty-one (23%) of 179 patients with crystalloid cardioplegia had conduction disturbances versus 141 (49%) of 289 patients with blood cardioplegia (p less than 0.001). Perioperative complete heart block requiring atrioventricular sequential pacing occurred in 20 patients with crystalloid cardioplegia versus 67 patients with blood cardioplegia (p less than 0.002), and atrioventricular block requiring permanent pacing was present in 4 and 12 patients (p less than 0.001), respectively. Left bundle-branch block was found in 8 patients given crystalloid cardioplegia and 28 patients with blood cardioplegia (p less than 0.05); right bundle-branch block, 12 and 68 patients (p less than 0.001); left anterior hemiblock, 8 and 37 patients (p less than 0.001); and interventricular conduction delay, 15 and 53 patients (p less than 0.005), respectively. Bifascicular block occurred in 4 patients receiving crystalloid cardioplegia versus 23 receiving blood cardioplegia (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Type V collagen synthesis and deposition by chicken embryo corneal fibroblasts in vitro.

Chick embryo corneal fibroblasts were grown in culture to study the processes whereby fibroblasts regulate the deposition and organization of the collagenous, secondary stroma. The effects of an existing type I collagen substratum, cell density, and serum concentration on type V collagen synthesis were investigated. Type V collagen represented approximately 20% of the total fibrillar collagen synthesized, regardless of whether the cells were subcultured, grown on untreated or collagen-coated plastic, grown under confluent or subconfluent conditions, or grown in the presence of low (0.1%) or high (10.0%) serum concentrations. The synthesis of type V collagen remained constant at 20% of the total collagen when cells were grown in 1.0% serum, even though total collagen synthesis increased nearly twofold when compared to total synthesis in 0.1% or 10.0% serum. Immunocytochemistry with anti-collagen, type-specific monoclonal antibodies revealed a homogeneous population of cells synthesizing types I and V collagen. The fibrils deposited by cells grown in a three-dimensional collagen matrix contained a helical epitope on the type V molecule that was inaccessible unless the fibrillar structure was disrupted, mimicking the situation in situ. The production in vitro of heterotypic fibrils, with a constant I/V ratio and molecular packing mimicking the natural stroma, offers opportunities for studying in more detail this important process, which is essential for optical transparency.

Animals↗
PubMed1988

Obesity and diabetes as risk factors for postoperative wound infections after cardiac surgery.

During a 30-month period, 20 median sternotomy wound infections or endocarditis occurred after 20 of 1204 (1.7%) cardiac surgery procedures in adults at the University of Maryland Hospital. We examined four risk factors related to the individual undergoing surgery: age, sex, and index of obesity (weight/height), and presence of diabetes mellitus. The odds ratio estimates of the relative risk of infection observed with use of a population control group were as follows: sex (female) 3.5 (p less than 0.05), obesity 2.0, and presence of diabetes mellitus 3.8. For a second control group matched for age, type of operative procedure, and date of operation, the estimated relative risks of infection were sex (female) 2.1, obesity 6.2 (p less than 0.05), and diabetes mellitus 2.0. More precise definition of the relative risk of sternotomy infection associated with obesity and diabetes is required to aid surgeons and patients in making judgments about the relative benefits of surgery and to alert nursing personnel to be particularly aware of early signs of infection in patients at high risk.

Adult↗