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Biomedical subjects

S K Ohri

Publications and source records attributed to S K Ohri.

At least 37 records · Page 2Linked to original sources
PubMed1996

Magnetic resonance coronary artery imaging for redo coronary operations.

Imaging the native coronary vessels using contrast angiography can be difficult in the context of redo coronary operations when native disease is severe. When previous vein grafts undergo aneurysmal dilatation, imaging of the native vessel is restricted by the inability to infuse a sufficient volume of contrast medium through the graft and into the native vessel. We present a case of a patient whose redo coronary artery bypass graft operation was planned on the basis of magnetic resonance imaging of his native coronary arteries and vein graft after unsuccessful coronary angiography.

Coronary Aneurysm↗
PubMed1996

Systemic inflammatory response and the splanchnic bed in cardiopulmonary bypass.

The splanchnic bed undoubtedly undergoes sub-clinical injury in the majority of patients undergoing routine CPB. Dependent upon patient and perfusion factors, this injury may be self-limiting or develop through a cascade of inflammatory mediators into multisystem organ failure. The gut may be damaged by the bioincompatibility of CPB, but it is, as a consequence of hypoperfusion and dysoxia, also a major source of bacterial and nonbacterial inflammatory mediators.

Cardiopulmonary Bypass↗
PubMed1995

Endotoxaemia detected during cardiopulmonary bypass with a modified Limulus amoebocyte lysate assay.

Cardiopulmonary bypass (CPB) is associated with blood heparin level fluctuations and a reduction in haematocrit due to crystalloid haemodilution. The effect of these changes on the reliability of the Limulus amoebocyte lysate (LAL) chromogenic microassay for the measurement of plasma endotoxin was assessed in vitro. It was shown that the assay could be significantly compromised by twofold haemodilution which can occur during CPB. The interference effect on the assay caused by CPB-associated heparin was not significant if a comparatively large amount of heparin (25 IU/ml) was added to the blood at the time of sampling. The effect of haemodilution was counteracted by prediluting plasma samples with crystalloid by a factor dependent on the sample haematocrit (to ensure that the proportion of plasma was similar in all samples). A correction was then required to determine the endotoxin level in the original sample. The modified assay was used to determine sequential plasma endotoxin levels in 14 patients undergoing hypothermic nonpulsatile CPB. Endotoxaemia occurred at the time of aortic cross-clamp release and reached a peak of 48.9 +/- 12.9 ng/l shortly before the end of CPB, which was significantly higher than baseline values pre-CPB (p < 0.05). Thereafter, there was a decline in endotoxin levels to 28.9 +/- 13.6 ng/l 24 hours later which was still significantly higher than baseline levels (p < 0.05). Peak endotoxaemia was a predictor of protracted hospital stay when compared with haemodynamic and tissue perfusion parameters.

Cardiopulmonary Bypass↗
PubMed1994

Carcinoid heart disease: early failure of an allograft valve replacement.

A woman who had carcinoid syndrome and carcinoid heart disease underwent tricuspid and pulmonary valve replacements with a xenograft and a cryopreserved allograft, respectively. Within 3 months of the operation severe pulmonary regurgitation and pulmonary hypertension refractory to medical therapy developed. Autopsy found the biomechanical tricuspid valve to be free of disease but the allograft in the pulmonary position was involved by carcinoid heart disease in a fashion similar to the excised native pulmonary valve.

Carcinoid Heart Disease↗
PubMed1994

Left ventricular function and coronary artery disease progression early after coronary bypass grafting.

To investigate the effects of coronary artery disease progression on left ventricular function in patients who suffer angina early after coronary artery bypass grafting, we studied the progression of coronary stenoses, the occurrence of graft occlusions, and measured left ventricular ejection fraction (regional and global) in 34 consecutive patients who underwent repeat angiography 25.2 +/- 3.5 (standard error of the mean) months postoperatively, from a total population of 550 patients who underwent bypass grafting. Resting left ventricular function and stenosis severity were assessed using a computerized, quantitative analysis system. Coronary stenosis progression was defined as an increase in the percentage of the stenotic occlusion by 30% or more, any increase in lesion severity that resulted in total coronary artery occlusion, or the occurrence of a new stenosis that occluded the artery by 50% or more. Group 1 comprised 21 patients with all grafts patent and group 2 comprised 13 patients with one or more grafts occluded (20 of 34 grafts). Coronary artery disease progressed in all patients in group 1, and this involved 22 of 54 (41%) grafted vessels and 3 of 15 (20%) nongrafted vessels (p < 0.05). Coronary artery disease progressed in 11 patients in group 2, involving 15 of 32 (47%) grafted vessels and 1 of 6 (17%) nongrafted vessels (p < 0.01). An increased collateral circulation was observed in both groups. The left ventricular ejection fraction remained unchanged in both groups (group 1, 0.60 +/- 0.03 versus 0.62 +/- 0.03; group 2, 0.62 +/- 0.05 versus 0.62 +/- 0.04 before and after bypass, respectively; p = not significant) and there was no difference between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Effects of cardiopulmonary bypass on gut blood flow, oxygen utilization, and intramucosal pH.

Studies documenting rises in endotoxin after cardiopulmonary bypass (CPB) have postulated gut mucosal hypoperfusion. We have investigated alterations in jejunal blood flow by laser Doppler flow measurement, intramucosal pH (pHi) by tonometry, and oxygen utilization in a canine model of hypothermic CPB (n = 11 dogs). After 10 minutes of hypothermic CPB, despite no major reduction in superior mesenteric artery flow, mucosal laser Doppler flow decreased to -38.2% +/- 9.3% of levels obtained before bypass (p = 0.008) and serosal laser Doppler flow, to -47.3% +/- 11.4% (p = 0.006). During the hypothermic phase, mesenteric oxygen consumption fell from 0.18 +/- 0.01 to 0.098 +/- 0.01 mL.min-1.kg-1 (p = 0.005), and mesenteric oxygen delivery fell from 1.97 +/- 0.39 to 1.14 +/- 0.12 mL.min-1.kg-1 (p = 0.05). There was no change in jejunal pHi. During the rewarming phase, there was a substantial increase in mucosal laser Doppler flow, peaking at +69.8% +/- 15.2% (p = 0.03), whereas serosal laser Doppler flow returned to values seen prior to CPB (-16.4% +/- 21.5%; p = 0.25). These changes coincided with a surge in oxygen consumption (0.33 +/- 0.042 mL.min-1.kg-1; p = 0.009), while mesenteric oxygen delivery remained depressed at 1.09 +/- 0.12 mL.min-1.kg-1 (p = 0.04). Jejunal pHi fell from a value of 7.36 +/- 0.04 before CPB to 7.12 +/- 0.07 (p = 0.02), thus indicating mucosal hypoxia. During the rewarming phase of hypothermic CPB, there is a disparity between mesenteric oxygen consumption and oxygen delivery with villus tip ischemia; these findings may explain the pathophysiology of endotoxemia during CPB.

Animals↗
PubMed1994

The effect of intestinal hypoperfusion on intestinal absorption and permeability during cardiopulmonary bypass.

BACKGROUND/AIMS: Mean arterial pressure is reduced during hypothermic cardiopulmonary bypass. The aim of this study was to assess whether this was associated with intestinal hypoperfusion and whether it affected intestinal absorption and permeability. METHODS: Twenty-six patients undergoing coronary artery bypass grafting underwent an intestinal absorption-permeability test involving ingestion of 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose. Ingestion took place 2 days before, within 3 hours, and 5 days after hypothermic cardiopulmonary bypass. Hemodynamic parameters and gastric mucosal laser Doppler blood flow were measured perioperatively in eight patients. RESULTS: Hypothermic (28 degrees C), nonpulsatile cardiopulmonary bypass resulted in a 25% reduction in mean blood pressure, 10% reduction in cardiac index, and a 46% reduction in gastric mucosal laser Doppler blood flow. There was 85.4%, 85.5%, and 73.6% reduction (P < 0.01) in active (3-O-methyl-D-glucose) and passive (D-xylose) carrier-mediated transport and passive, nonmediated transcellular (L-rhamnose) transport in the immediate postoperative period, respectively. The differential urine excretion of lactulose/L-rhamnose increased sixfold. All parameters returned to control levels by the fifth postoperative day. CONCLUSIONS: Cardiopulmonary bypass, while maintaining generally acceptable levels of hemodynamic performance, is associated with significant intestinal hypoperfusion and malabsorption of monosaccharides, which may have implications for enteral drug treatment in the immediate postoperative period.

Adult↗
PubMed1994

Evidence for thyroid development from the fourth branchial pouch.

Fourth branchial pouch anomalies are rarely reported. A case is described of an isolated branchial cyst which was found to contain ectopic thyroid tissue. This case, together with four others previously reported, support the theory that the thyroid gland may receive contributions from the fourth branchial pouch during development.

Branchioma↗
PubMed1994

The effect of cardiopulmonary bypass on gastric and colonic mucosal perfusion: a tonometric assessment.

In a study to assess the potential effect of nonpulsatile hypothermic cardiopulmonary bypass (CPB), intramucosal pH (pHi) of the gastric and colonic mucosae was determined by tonometry (n = 8). During the hypothermic phase of CPB, gastric and colonic pHi did not change significantly. Forty minutes after the start of rewarming, despite increases in the cardiac index and mean arterial blood pressure, gastric pHi fell from 7.53 +/- 0.02 to 7.31 +/- 0.03 (p = 0.017) and colonic pHi fell from 7.50 +/- 0.02 to 7.32 +/- 0.03 (p = 0.028). Forty minutes after the end of CPB both the colonic (p = 0.017) and gastric (p = 0.046) pHi remained depressed below pre-CPB values. The difference in the arterial (pHa) and the gastric mucosal pH changed from -0.097 before CPB to 0.016, 40 minutes after the end of CPB (p = 0.027). This alteration in the pHa-pHi underlines the importance of measuring intramucosal pH by tonometry, since the pHa and pHi may move in opposite directions during episodes of haemodynamic stress. Both the gastric and colonic pHi were found to have a linear correlation with the pHa, although changes in the gastric pHi (r = 0.41, p = 0.018) were more strongly correlated with the pHa than the colonic pHi (r = 0.23, p = 0.19) in the rewarming phase of CPB and the immediate post-CPB period when there was a tendency towards intramucosal acidosis. The development of intramucosal acidosis in the rewarming and immediate post-CPB phases following hypothermic nonpulsatile CPB may impair the gut barrier and predispose patients to the absorption of luminal toxins.

Blood Pressure↗
PubMed1993

Cardiopulmonary bypass impairs small intestinal transport and increases gut permeability.

Gastrointestinal damage occurs in 0.6% to 2% of patients after cardiopulmonary bypass (CPB), and carries a mortality of 12% to 67%. The incidence of subclinical gastrointestinal damage may be much greater. We examined the effects of nonpulsatile, hypothermic CPB on intestinal absorption and permeability in 41 patients. Bowel mucosal saccharide transport and permeation were evaluated using 100 mL of an oral solution containing 3-O-methyl-D-glucose (0.2 g), D-xylose (0.5 g), L-rhamnose (1.0 g), and lactulose (5.0 g) to assess active carrier-mediated, passive carrier-mediated, transcellular, and paracellular transport, respectively, with a 5-hour urine analysis. Patients were studied before, immediately after, and 5 days after CPB. Immediately after CPB there was a decrease in urinary excretion of 3-O-methyl-D-glucose (from 34% +/- 2.2% to 5.2% +/- 0.7%; p < 0.0001), D-xylose (from 25.4% +/- 1.4% to 4.1% +/- 0.8%; p < 0.0001), and L-rhamnose (from 8.3% +/- 0.6% to 2.6% +/- 0.4%; p < 0.0001). The permeation of 3-O-methyl-D-glucose and D-xylose returned to normal levels 5 days after CPB, but that of L-rhamnose remained significantly below pre-CPB values at 6.6% +/- 0.5% (p = 0.004). However, the permeation of lactulose increased after CPB (from 0.35% +/- 0.04% to 0.59% +/- 0.1%; p = 0.018), and the lactulose/L-rhamnose gut permeability ratio increased markedly (from 0.045 +/- 0.04 to 0.36 +/- 0.08; normal = 0.06 to 0.08; p = 0.004). Patients who had a CPB time of 100 minutes or more had a greater increase in gut permeability (p = 0.049).(ABSTRACT TRUNCATED AT 250 WORDS)

3-O-Methylglucose↗
PubMed1993

Primary repair of iatrogenic thoracic esophageal perforation and Boerhaave's syndrome.

Ten patients seen at our unit over a 24-month period with either iatrogenic (n = 5) or spontaneous thoracic esophageal perforations (n = 5) were retrospectively reviewed. Five patients were seen within 24 hours of onset of symptoms, and 5 were seen after 24 hours or later. There was no significant difference in the presentation or subsequent clinical course in patients seen less or more than 24 hours after the onset of symptoms. Nine patients underwent primary repair together with drainage of the mediastinum, and in 1 of these a Heller's myotomy was also performed for achalasia. One patient had a two-stage esophagogastrectomy for a benign esophageal stricture. One patient (10%) with a spontaneous perforation died 48 hours after operation and was found at postmortem examination to have an in situ carcinoma at the site of the perforation. Four patients (40%) had nonfatal complications. Fistulas developed in 3 patients (30%); in 1 of these patients a second thoracotomy and a further rib resection was required for drainage of a mediastinal abscess. An esophago-cutaneous fistula and a persistent mediastinal abscess developed in 1 patient (10%) and necessitated two further thoracotomies for effective drainage. The mean hospital stay was 38.4 +/- 25.4 days (range, 16 to 76 days). The findings of this study suggest that primary repair combined with a drainage procedure is the treatment of choice for patients with a perforated intrathoracic esophagus, including those seen more than 24 hours after the onset of symptoms.

Aged↗
PubMed1993

Acquired segmental emphysema: the enlarging spectrum of Swyer-James/Macleod's syndrome.

Three cases of Macleod's syndrome are described, all of which required surgical resections for distressing symptoms. This provided a rare opportunity to examine the pathologic features of a condition that is usually diagnosed on its radiologic features, and the etiology of which remains unestablished. Three patients (2 women and 1 man), aged 20, 23, and 24 years, were referred from respiratory physicians because of unilateral hyperlucent lungs and associated symptoms. All 3 patients had unilateral hyperlucent lungs, but only 1 patient had demonstrable mediastinal shift on expiratory and inspiratory chest computed tomographic scan. Segmentectomies were performed (n = 4) in all the patients without perioperative morbidity or mortality. Patients have been followed up between 6 and 18 months, and remain asymptomatic with a return to normal lifestyle. Histologic examination of the specimens found inflammation of the bronchus in all 3 patients, but only two specimens had evidence of bronchiolar inflammation. In only 1 patient was there a reduction in bronchiole number. All 3 patients showed presence of emphysema. These cases are notable for the segmental distribution of the disease. Pathologic examination lends support to the theory that previous respiratory tract infection may play a role in the pathogenesis of this condition.

Adult↗
PubMed1993

Angiosarcoma of the heart causing cardiac rupture: a rare cause of hemopericardium.

Cardiac rupture as a complication of primary cardiac tumors has rarely been reported in the literature. The diagnosis is difficult to establish preoperatively, but echocardiography may provide the best assessment of cardiac damage. We found a loculated pericardial effusion on two-dimensional echocardiography, a finding that has been documented in two of the previous four case reports. A case of right atrial rupture is reported with review of other cases from the literature.

Heart Neoplasms↗
PubMed1993

Enhanced excretion of urinary leukotriene E4 in coronary artery disease and after coronary artery bypass surgery.

BACKGROUND: Excretion of leukotriene (LT) E4, the major urinary metabolite of cysteinyl leukotrienes in humans, is increased in patients with unstable angina and myocardial infarction, suggesting that cysteinyl leukotrienes are released into the circulation during episodes of myocardial ischaemia. Furthermore, leukotrienes are known to induce potent vasoconstrictive effects in human atherosclerotic coronary arteries and the saphenous vein. Accordingly, we measured urinary excretion of LTE4 in patients with stable coronary artery disease both before and after coronary artery bypass surgery, and in age-matched healthy controls, to study the relation between the systemic synthesis of cysteinyl leukotrienes and stable coronary artery disease, as well as the possible changes after bypass surgery. METHODS: LTE4 was isolated from urine samples by solid-phase extraction, purified by reverse-phase high-performance liquid chromatography, and subsequently quantified by radioimmunoassay. RESULTS: In patients with coronary artery disease, preoperative urinary LTE4 levels were normally distributed on a log10 scale, with a genometric mean of 115 pmol/mmol creatinine (95% confidence interval 67-196) compared with 63.0 pmol/mmol creatinine (95% confidence interval 47.9-82.7) in healthy subjects (P < 0.05). Urinary LTE4 levels increased further in patients after coronary artery bypass surgery with levels peaking on the second day after surgery (266.2 pmol/mmol creatinine, 95% confidence interval 167.2-423.9) at significantly higher than preoperative levels (P < 0.02), and then decreasing by day 3. CONCLUSIONS: Levels of cysteinyl leukotrienes are raised in coronary artery disease patients both before and after coronary artery bypass surgery. As these mediators are capable of inducing potent vasoconstrictive effects on atherosclerotic coronary arteries and the saphenous vein, our results could have important clinical and possibly therapeutic implications.

Adult↗
PubMed1993

Ileal conduit for reconstruction of the duodenum following right hemicolectomy and pancreaticoduodenectomy for malignant duodenocolic fistula.

We describe a case of malignant duodenocolic fistula in which after a radical resection of right hemicolectomy and pancreaticoduodenectomy, the duodenal defect was reconstructed using a conduit of transposed ileum. This technique, not previously described, offers an alternative to 'duodenal patching', which allows only limited duodenal resection, or gastroenterostomy with its attendant side-effects such as dumping syndrome.

Aged↗
PubMed1992

Palliative intubation for dysphagia in patients with carcinoma of the esophagus.

One hundred seven consecutive patients seen over a 6-year period with dysphagia secondary to advanced primary carcinoma of the esophagus underwent intubation. One hundred five patients underwent pulsion intubation. In 2 patients pulsion intubation was not possible, and laparotomy and traction intubation was performed. For the intubated group there were 65 men and 40 women (ratio, 1.6:1), with a mean age of 71.3 +/- 10.5 years (range, 36 to 92 years). Of the 105 patients who had pulsion intubation, a perforation developed in 11 (10.5%), which was responsible for the death of 4 patients (3.8%). A further 3 patients died of malignant cachexia, which resulted in an overall mortality of 6.7%. Late complications included tube displacement (4 patients; 3.8%) and tube obstruction (32 patients; 30.5%). Tube obstruction was due to advancement of malignant disease in 26 patients (81.2%) and food bolus impaction in the remaining 6 patients (18.8%). Pulsion intubation for advanced carcinoma of the esophagus can be performed with a low morbidity and early mortality. However, there is a substantial long-term morbidity of tube obstruction in almost a third of survivors.

Adenocarcinoma↗