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Biomedical subjects

S K Ohri

Publications and source records attributed to S K Ohri.

At least 19 recordsLinked to original sources
PubMed2002

A prospective randomized study to evaluate the renoprotective action of beating heart coronary surgery in low risk patients.

OBJECTIVES: Cardiopulmonary bypass (CPB) is widely regarded as an important contributor to renal failure, a well recognized complication following coronary artery surgery (coronary artery bypass grafting (CABG)). Anecdotally off-pump coronary surgery (OPCAB) is considered renoprotective. We examine the extent of renal glomerular and tubular injury in low-risk patients undergoing either OPCAB or on-pump coronary artery bypass (ONCAB). METHODS: Forty low-risk patients with normal preoperative cardiac and renal functions awaiting elective CABG were prospectively randomized into those undergoing OPCAB (n=20) and ONCAB (n=20). Glomerular and tubular injury were measured respectively by urinary excretion of microalbumin and retinol binding protein (RBP) indexed to creatinine (Cr). Daily measurements were taken from admission to postoperative day 5. Fluid balance, serum Cr and blood urea were also monitored. RESULTS: No mortality or renal complication were observed. Both groups had similar demographic makeup, Parsonnet score, functional status and extent of coronary revascularization (2.1+/-1.0 vs. 2.5+/-0.7 grafts; P=0.08). Serum Cr and blood urea remained normal in both groups throughout the study. A significant and similar rise in urinary RBP:Cr occurred in both groups peaking on day 1 (3183+/-2534 vs. 4035+/-4079; P=0.43) before reapproximating baseline levels. These trends were also observed with urinary microalbumin:Cr (5.05+/-2.66 vs. 6.77+/-5.76; P=0.22). Group B patients had a significantly more negative fluid balance on postoperative day 2 (-183+/-1118 vs. 637+/-847 ml; P=0.03). CONCLUSIONS: Although renal complication or serum markers of kidney dysfunction were absent, sensitive indicators revealed significant and similar injury to renal tubules and glomeruli following either OPCAB or ONCAB. These results suggest that avoidance of CPB does not offer additional renoprotection to patients at low risk of perioperative renal insult during CABG.

Aged↗
PubMed2002

Off-pump coronary artery surgery.

Cardiopulmonary bypass has several associated deleterious effects that include a systemic inflammatory response, coagulopathy, central nervous system complications and a variable degree of end-organ damage. The recent upsurge in interest in "beating-heart" surgery attempts to avoid these deleterious effects. Advances in surgical technique, such as the use of intracoronary shunts and the Octopus retractor, have made beating-heart surgery a reality. The challenges for the anaesthetist are greater than for coronary artery surgery using cardiopulmonary bypass, and whilst some advantages are proven, such as the lack of the inflammatory response and the decreased need for blood or blood products, others have yet to be proved and there is a need for further research. The advantages and disadvantages need to be evaluated in randomised studies in order to confirm the safety and efficacy of these new techniques in terms of long-term graft patency and decreased morbidity.

Anesthesia, General↗
PubMed2001

Endoscopic vein harvesting with the aid of carbon dioxide insufflation.

Endoscopic harvesting of the long saphenous vein has been introduced to decrease the morbidity of obtaining venous conduit for coronary artery bypass grafting. Herein is described an endoscopic method using carbon dioxide insufflation into the tissues around the vein. This has several advantages; improved vision, no physical retraction required, easier development of tissue planes, and improved hemostasis.

Carbon Dioxide↗
PubMed2001

Autotransfusion decreases blood usage following cardiac surgery -- a prospective randomized trial.

INTRODUCTION: 10% of blood issued by the National Blood Service (220,000) is utilised in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We tested the efficacy of autotransfusion of washed postoperative mediastinal fluid in a prospective randomized trial. PATIENTS AND METHODS: 166 patients undergoing coronary artery bypass grafting (CABG), valve or CABG + valve procedures were randomized into three groups. The indication for transfusion was a postoperative haemoglobin (Hb) < 10 g/l or a packed cell volume (PCV) < 30. When applicable, group A patients received washed post-operative drainage fluid. Group B all received blood processed from the cardiopulmonary bypass (CPB) circuit following separation from CPB and if appropriate washed post-operative drainage fluid. Group C were controls. Groups were compared using analysis of variance. RESULTS: There was no significant difference in age, sex, type of operation, CPB time and preoperative Hb and PCV between the groups. Blood requirements were as shown. [table - see text] Twelve patients in group A and 10 in group B did not require a homologous transfusion following processing of the mediastinal drainage fluid. CONCLUSION: Autotransfusion of washed postoperative mediastinal fluid can decrease the amount of homologous blood transfused following cardiac surgery. There was no demonstrable benefit in processing blood from the CPB circuit as well as mediastinal drainage fluid.

Adult↗
PubMed2001

Transventricular cannulation of the aorta: a useful technique in acute aortic dissection.

A 39-year-old morbidly obese man suffered type-A acute aortic dissection. At operation, both external iliac and common femoral arteries were thrombosed. Transventricular cannulation of the ascending aorta provided the only means of maintaining adequate flow on cardiopulmonary bypass (CPB) to support an unusually high body mass index. This method of arterial cannulation for CPB was initially described in paediatric patients. We review the application of this technique in the adult population.

Adult↗
PubMed2001

A genetically engineered human Kunitz protease inhibitor with increased kallikrein inhibition in an ovine model of cardiopulmonary bypass.

A recombinant human serine protease inhibitor known as Kunitz protease inhibitor (KPI) wild type has functional similarities to the bovine Kunitz inhibitor, aprotinin, and had shown a potential to reduce bleeding in an ovine model of cardiopulmonary bypass (CPB). The aim of this study was to assess KPI-185, a modification of KPI-wild type that differs from KPI-wild type in two amino acid residues and which enhances anti-kallikrein activity in a further double-blind, randomized study in an ovine model of CPB, and to compare with our previous study of KPI-wild type and aprotinin in the same ovine model. Post-operative drain losses and subjective assessment of wound 'dryness' showed no significant differences between KPI-185 and KPI-wild type, despite the significant enhancement of kallikrein inhibition using KPI-185 seen in serial kallikrein inhibition assays. These preliminary findings support the hypothesis that kallikrein inhibition is not the major mechanism by which Kunitz inhibitors such as aprotinin reduce perioperative bleeding.

Amino Acid Sequence↗
PubMed2000

Novel application of vacuum assisted closure technique to the treatment of sternotomy wound infection.

Infection of the sternotomy wound is a potentially devastating and sometimes lethal complication following cardiac surgery. Established treatment may involve a combination of debridement, packing, delayed closure, plastic reconstruction, re-wiring and irrigation dependent on the severity of infection. Vacuum assisted closure, originally adopted for the treatment of non-healing wounds, has recently gained popularity among various surgical specialities in managing complex wound infection. Here we describe this novel technique of managing postoperative sternal wound infection.

Cardiac Surgical Procedures↗
PubMed1999

Primary esophageal repair for Boerhaave's syndrome.

BACKGROUND: Boerhaave's syndrome is the most sinister cause of esophageal perforation. The mediastinal contamination with microorganisms, gastric acid, and digestive enzymes results in a mediastinitis that is often fatal if untreated. METHODS: We present a series of 21 patients seen in our unit in the 10 years 1987 to 1996. Esophageal repair was performed in 17 (81%) of them. After the resuscitation of the patient in the intensive care unit, our strategy is primary esophageal repair with a single layer of interrupted absorbable sutures combined with mediastinal toilet, mediastinal drainage, and drainage gastrostomy. The majority of patients (12/21) were referred more than 24 hours after perforation. RESULTS: The mean age of the patients was 60+/-17 years. The mean stay in the intensive care unit was 1.6+/-1.8 days and the median hospital stay, 14 days. There were three deaths, an overall mortality rate of 14.3%. CONCLUSIONS: When combined with mediastinal toilet, mediastinal drainage, and drainage gastrostomy, primary esophageal repair for Boerhaave's syndrome gives an acceptable mortality and should not be reserved for patients seen within 24 hours after spontaneous rupture.

Aged↗
PubMed1999

Autotransfusion of washed shed mediastinal fluid decreases the requirement for autologous blood transfusion following cardiac surgery: a prospective randomized trial.

OBJECTIVES: The National Blood Service issues 2.2 million units of blood per year, 10% of these (220000) are utilized in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We test the efficacy of autotransfusion following surgery in a prospective randomized trial. METHODS: One hundred and twelve patients undergoing CABG, valve or CABG + valve procedures were randomized into two groups. Group A received washed postoperative drainage fluid and group C were controls. The indication for transfusion was a postoperative haemoglobin (Hb) < 10 g/l or a PCV < 30. There was no significant difference in preoperative and operative variables between the groups. RESULTS: Twenty-eight patients in group A and 46 in group C required homologous transfusion (P = 0.0008). Group A patients required 298+/-49 ml of banked blood per patient, group C 508+/-49 ml (P = 0.003). There was no difference in total blood required (volume autotransfused + volume banked blood transfused) between the groups (group A 404+/-50 ml, group C 508+/-50 ml) or in mean total mediastinal fluid drainage (group A 652+/-51 ml, group C 686+/-50ml). The mean Hb concentration was significantly higher in group A on day 1 (11.2 g/dl+/-51 vs. 10.6 g/dl+/-13 (P = 0.002)). No morbidity was associated with autotransfusion. CONCLUSION: Autotransfusion can decrease the amount of homologous blood transfused following cardiac surgery. This represents a benefit to the patient and a decrease in cost to the health service.

Aged↗
PubMed1999

Tricuspid valve replacement: bioprostheses are preferable.

BACKGROUND AND AIM OF THE STUDY: Tricuspid valve replacement (TVR) is rarely undertaken, most surgeons preferring to use conservative tricuspid valve procedures. Thus, limited data are available in patients following TVR. The purpose of this study was to analyze the early and late results in 87 patients (52 tissue valves, 35 mechanical prostheses) who underwent TVR between January 1973 and September 1996. METHODS: The patient group comprised 74 (85%) females and 13 (15%) males; mean (+/- SD) age was 59.4 +/- 12.8 years; range: 15 to 81 years). Forty-four patients (51%) had undergone at least one previous cardiac operation. There were 19 (23%) isolated TVRs, 43 (49%) triple valve replacements, and 25 (29%) double valve replacements. Total cumulative follow up was 707 patient-years (pt-yr) (tissue valves 393 pt-yr, mechanical valves 314 pt-yr); mean follow up was 8.1 years (range: 0 to 23.6 years). RESULTS: The early (30-day) mortality rate was 10.3% (n = 9; tissue 7, mechanical 2, p = 0.28). Logistic regression identified prolonged cardiopulmonary bypass time (p <0.03) and advanced NYHA functional class (p <0.007) as risk factors for operative death. No risk factors were significant on multiple logistic regression analysis. Mean (+/- SEM) survival rate was 68 +/-5.3% (n = 50) at 5 years, 52 +/- 5.9% (n = 36) at 10 years, 35 +/- 6% (n = 20) at 15 years, and 16 +/- 5.3% (n = 7) at 20 years. Freedom from tricuspid valve reoperation at 5, 10 and 15 years was 93 +/- 3.3% (n = 46), 83 +/- 5.8% (n = 33) and 71 +/- 2.8% (n = 17) respectively. Eleven patients required tricuspid valve reoperation: six mechanical valves (five for prosthetic valve thrombosis and one for mechanical failure secondary to pannus ingrowth), and five tissue valves (two for prosthetic valve endocarditis and three for prosthetic valve degeneration). Freedom from reoperation at 5, 10 and 15 years for tissue prostheses was 97 +/- 2.5%, 89 +/- 6.3% and it was 70 +/- 12%, and 86 +/- 7.4%, 74 +/- 9.9% and 68 +/-11% for mechanical prostheses. The mechanical prostheses required reoperation earlier after the initial surgery. CONCLUSIONS: We recommend the use of a bioprosthesis in the tricuspid position because of its initial durability and low reoperation rate.

Adolescent↗
PubMed1998

Iatrogenic oesophageal perforations: a clinical review.

Thirty patients with iatrogenically induced perforation of the oesophagus were managed in our unit between January 1986 and December 1996. Thirteen (43%) of these injuries were referred after upper gastrointestinal endoscopy performed by physicians. Ten (33%) cases were referred by ENT surgeons and general surgeons referred 7 (23%) cases. Of these patients, 15 (50%) had no abnormality of the oesophagus found before perforation. Only 18 (60%) of patients were referred within 24 h of injury. The mean duration of care required in the intensive care unit was 1.5 days +/- 2.5 days and the mean inpatient hospital stay 26.5 days +/- 22.1 days. The mortality was 10% (three cases). Oesophageal perforation remains a serious life-threatening injury. The early diagnosis of this uncommon condition requires a high index of suspicion as the symptoms are often non-specific. Identification of the site of perforation is necessary as the management of cervical and thoracic perforations differs considerably. Early referral combined with appropriate therapy would appear to result in a better outcome than previously published data. It is therefore suggested that patients with this relatively rare condition should be referred as soon as possible to a centre with expertise in its management.

Adult↗
PubMed1997

Effect of cardiopulmonary bypass perfusion protocols on gut tissue oxygenation and blood flow.

BACKGROUND: Previous studies in patients undergoing cardiopulmonary bypass (CPB) have documented gastric mucosal hypoperfusion and hypoxia. This study examines the influence of the CPB protocol on the adequacy of gut blood flow and oxygenation. METHODS: Twenty-four patients were prospectively randomized into one of four CPB groups: nonpulsatile hypothermic (NP 28); pulsatile hypothermic (P 28); non-pulsatile normothermic (NP 37); and pulsatile normothermic (P 37). Gastric wall blood flow was assessed using laser Doppler flow measurement and gastric mucosal oxygenation (intramucosal pH), using tonometry. RESULTS: After 10 minutes of CPB, the NP 28 group had the greatest reduction in gastric wall blood flow (-60.6% +/- 3.8%) compared with baseline (p < 0.05). Thirty minutes into CPB, the P 37 group had less gastric mucosal hypoperfusion (-9.7% +/- 10.3%) than the NP 28 patients (-53.0% +/- 8.6%; p < 0.05). All groups showed a hyperemic response immediately after CPB. No significant differences between the four groups were found for gastric mucosal oxygenation during or after CPB. A progressive decline occurred in this variable during the period 3 to 4 hours after CPB. At this time, total-body oxygen consumption and extraction were at their maximum. CONCLUSIONS: This study found that perfusion protocol can influence mucosal blood flow, but other overriding factors that operate during and after CPB act to cause mucosal hypoxia. These findings, particularly the timing of mucosal hypoxia, may have implications for centers contemplating early extubation or "fast tracking" of patients after CPB.

Adult↗
PubMed1997

Homograft as a conduit for superior vena cava syndrome.

This report outlines the management of a 30-year-old man with severe multiresistant mycobacterium tuberculosis of his right lung. Despite medical therapy he had open tuberculosis with positive sputum smears. A right pneumonectomy was undertaken, but due to distorted hilar anatomy, the superior vena cava was resected. Postoperatively, superior vena cava syndrome developed and failure of venous drainage was demonstrated by bilateral arum venography and computed tomographic scanning. The superior vena cava syndrome was successfully relieved using an aortic homograft as a superior vena cava replacement instead of a spiral vein graft or a prosthetic conduit.

Adult↗
PubMed1997

Thoracoscopic debridement of empyema thoracis.

BACKGROUND: The primary treatment of empyema thoracis remains intercostal tube drainage together with antibiotics. Failure of primary treatment has until recently been an indication for thoracotomy and decortication. Video-assisted thoracoscopic debridement (VATD) has increased the available treatment options but requires validation. METHODS: A retrospective analysis was undertaken of 44 consecutive patients who presented for surgical treatment of empyema thoracis over a 3-year period. RESULTS: Two patients were unsuitable for VATD and were treated with open decortication (OD). Thirty patients were successfully treated by VATD. Two patients were converted to OD at the first operation, and 10 patients required OD as a second procedure. The mean duration of preoperative symptoms before referral was 37.6 +/- 11.8 days (VATD) and 40.1 +/- 11.6 days (OD) (p = not significant). The mean duration of hospitalization before transfer was 13.7 +/- 2.4 days (VATD) and 11.5 +/- 3.4 days (OD) (p = not significant). Intercostal drainage was required for 4.0 +/- 0.3 days (VATD) and 8.5 +/- 2.0 days (OD) (p = 0.004). The postoperative hospital stay was 5.3 +/- 0.4 days (VATD) and 10.3 +/- 2.1 days (OD) (p = 0.001). CONCLUSIONS: Primary surgical therapy with VATD should be considered for all patients with pleural empyema, irrespective of the duration of symptoms. This approach does not preclude OD as a secondary procedure or conversion to OD after initial thoracoscopic assessment. The major advantages of VATD over OD are a shorter duration of postoperative intercostal drainage and reduced postoperative hospitalization.

Debridement↗
PubMed1996

Genetically engineered serine protease inhibitor for hemostasis after cardiac operations.

BACKGROUND: The serine protease inhibitor aprotinin has been widely reported for its beneficial action in limiting blood loss after cardiopulmonary bypass (CPB). A potent human serine protease inhibitor known as protease nexin II or amyloid precursor protein has been recently isolated. A recombinant protein known as recombinant Kunitz protease inhibitor (rKPI; Scios Nova, Mountain View, CA) with sequence homology to the protease nexin II-amyloid precursor protein molecule has been manufactured. METHODS: Recombinant Kunitz protease inhibitor was assessed in an ovine model of CPB as a hemostatic agent after CPB. Sheep (n = 22) underwent CPB for 90 minutes. Two thoracic drains were sited and drain losses collected for a period of 3 hours after CPB. Wounds were subjectively assessed before closure for "dryness" using a visual analogue scale. Sheep were randomized to control (n = 8), aprotinin (n = 8), and rKPI (n = 6) groups. RESULTS: Control animals had a drain loss of 409.4 +/- 39.4 mL/3 h, compared with 131.3 +/- 20.3 mL/3 h for the aprotinin group and 163.7 +/- 34.3 mL/3 h for the rKPI group (p = 0.16). Hemoglobin loss was 11.6 +/- 3.6, 6.02 +/- 2.1, and 4.6 +/- 1.2 g/3 h for the control, rKPI, and aprotinin groups respectively (p = 0.25). The subjective analysis of the wounds at the end of CPB found aprotinin (1.25 +/- 0.16; p < 0.05) and rKPI (1.17 +/- 0.17; p < 0.05) animals to score significantly lower than control animals (2.63 +/- 0.42). CONCLUSIONS: On the basis of these in vivo findings, genetic modification may yield a more efficacious serine protease inhibitor with the inherent advantages of using a human-based protein.

Animals↗