Faculty Bibliography

Laryngeal exposure to acid and aspiration of gastric contents may lead to severe respiratory disorders. This study utilizes the canine model of Gastroesophageal reflux (GER) to identify whether lower esophageal dysfunction is associated with upper and lower airway pathology. MATERIALS AND METHODS: Five mongrel dogs underwent GER-creating surgery (partial cardiomyectomy). Laryngeal reflux finding score (RFS), lipid-laden macrophage index (LLMI) and BAL fluid cell differential were obtained before and after surgery. RESULTS: Partial cardiomyectomy in dogs significantly increased the Reflux index (RI) from 0.38 +/- 0.21% to 7.56 +/- 2.89% (P = 0.048), the duration of the longest reflux episode (DLRE) from 1.22 +/- 1.19 min to 66.2 +/- 42.03 min postoperatively (P = 0.049) and the total number of episodes in 24 hr from 2.06 +/- 1.03 to a postoperative value of 19.24 +/- 4.79. There was no statistically significant change in values for RFS, LLMI, and BAL fluid cell differential after the induction of GER. CONCLUSIONS: Acid reflux to the proximal esophagus of this animal model did not cause laryngeal exposure to acid or aspiration of gastric content. The results of this study suggest that presence of GER, secondary to lower esophageal dysfunction is not necessarily associated with upper and lower airway pathology.

BACKGROUND: Monitoring of intrapleural pressure (IPP) is used for evaluation of lung function in a number of pathophysiological conditions. We describe a telemetric method of non-invasive monitoring of the IPP in conscious animals intermittently or continuously for a prolonged period of time. MATERIALS AND METHODS: After IACUC approval, six mongrel dogs were used for the study. After sedation, each dog was intubated and anesthetized using 0.5% Isoflurane. A telemetric implant model TL11M2-D70-PCT from Data Science International was secured subcutaneously. The pressure sensor tip of the catheter from the implant was inserted into the pleural space, and the catheter was secured with sutures. The IPP signals were recorded at a sampling rate of 100 points/second for 30 to 60 min daily for 4 days. From these recordings, the total mean negative IPP (mmHg), and the total mean negative IPP for a standard time of 30 min were calculated. In addition, the actual inspiratory and expiratory pressures were also measured from stable recording of the IPP waveforms. RESULTS: In six dogs, the total mean +/- SD negative IPP was -10.8 +/- 10.6 mmHg. After normalizing with respect to acquisition time it was -13.2 +/- 11.2 mmHg/min. The actual inspiratory pressure was -19.7 +/- 15.3, and the expiratory pressure was -11.0 +/- 12.9. CONCLUSIONS: Our study demonstrates that telemetric monitoring of IPP can be performed reliably and non-invasively in conscious experimental animals. The values for IPP in our study are compatible with the results of other investigators who used different methods of IPP measurement. Further work may show this method to be helpful in understanding the pathophysiology of various breathing disorders

BACKGROUND: The circadian variation that affects atherosclerosis has not been studied in the surgical patient. The circadian variation in mortality dependent on the time of surgery was examined in patients undergoing coronary artery bypass graft (CABG) surgery. METHODS: A 4-year retrospective review of all CABG patients (n = 3140) from 1999 to 2002 was undertaken. The patients were divided into elective, urgent, and emergency cases. The cases were subdivided according to the start time of the operation as morning (7 AM to 2 PM = AM), afternoon (2 PM to 8 PM = AF), and night (8 PM to 7 AM = NT). The outcome was mortality within 30 days and compared for three different time frames: (1) AM versus AF (2) AM versus NT (3) AF versus NT for each prioritized group. Risk factors and number of anastamoses were compared for each group. Sigma Statistical package and Z-test for two group comparison were used for analysis. t-Test was used to compare age and ejection fraction. RESULTS: No statistically significant difference in mortality was observed for the elective and urgent groups for each of the time periods compared. The emergency cases had significantly increased deaths in the AM and NT compared to the AF (p < 0.01 and p < 0.05, respectively). There was no statistically significant difference with respect to age, gender, number of anastamoses performed, ejection fraction, and preoperative risk factors between groups. CONCLUSIONS: The mortality for nonemergent CABG is independent of the timing of surgery. Circadian variation does not influence the outcome in cardiac surgical patients

Cardiac papillary fibroelastomas (CPF) are benign endocardial papillomas commonly formed from valve endothelium. The majority of tumors are found on the left side of the heart, with only a few case reports of pulmonary valve fibroelastomas. We report here a case of pulmonary valve papillary fibroelastoma that was successfully managed with simple excision of the mass

BACKGROUND: The quantity of lipids in alveolar macrophages is used clinically as an indicator of aspiration, which is associated with increased lung inflammation. This is determined in the macrophages obtained from bronchoalveolar lavage (BAL) and is expressed as lipid-laden macrophage index (LLMI). Although there is ample data on LLMI in human subjects, there is no published data pertaining to the baseline measures of the LLMI in canines, which are extensively used for experimental studies on gastroesophageal reflex (GER) and airway diseases. Primary aim of the present study was to collect data pertaining to the cytology and LLMI in BAL fluids obtained from healthy dogs. MATERIALS AND METHODS: Eight dogs underwent a bronchoscopy with BAL collection, and esophageal pH monitoring to determine the reflux index (RI). The BAL fluid was processed and reviewed under a microscope to determine the proportions of the various cell types and the LLMI. RESULTS: The median RI among the subjects was found to be 0.6 (0.0, 1.2). The BAL cytology analysis showed 77.5% (71.0, 83.5) macrophages, 21.0 (13.0, 24.5) lymphocytes and 2.5 (1.5, 5.0) neutrophils. The median LLMI was found to be 156 (111, 208). CONCLUSIONS: Although the differential cell counts in the dogs' BAL fluid was comparable to that of other experimental animals and humans, the LLMI was distinctly higher than the corresponding value reported for other species. As LLMI is a valuable modality for evaluation of intrapulmonary pathophysiology, these data on LLMI can be used as a species-specific standard for canine subjects used for experimental studies on GER and airway diseases.

The association between gastroesophageal reflux (GER) and upper airway obstruction in children is recognized but not well understood. Our objective was to determine if the creation of a model of upper airway obstruction in dogs would cause GER and to determine if the GER is related to intrathoracic pressure changes. Five dogs underwent evaluation with esophageal manometry and pH probe at baseline and 1 week after creation of an upper airway obstruction. Airway obstruction was created by placement of a fenestrated cuffed tracheostomy tube, which was then capped and the cuff was inflated, requiring the animals to breathe via the fenestrations. The negative inspiratory pressure (Pes) (+/- SD) increased from 11.8 +/- 4.8 cm H(2)O at baseline to 17.6 +/- 4.9 cm H(2)O 1 week after creation of an airway obstruction (p = .029). None of the dogs had GER at baseline with a reflux index (RI) value of 0.0; however, 1 week after creation of airway obstruction, three out of five dogs had GER, with a mean RI value of 21.2 +/- 21.2. There was a significant (p = .023) correlation (r = .928) of the changes in Pes and RI values following airway obstruction. Upper airway obstruction (UAO) does cause GER in this canine model. Severity of GER is significantly correlated with Pes changes.