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Biomedical subjects

K G Belani

Publications and source records attributed to K G Belani.

At least 19 recordsLinked to original sources
PubMed1999

Accuracy of radial artery blood pressure determination with the Vasotrac.

PURPOSE: To evaluate the accuracy of a new non-invasive method (Vasotrac) to measure blood pressure (BP) with accompanying arterial wave-form and pulse-rate display when compared with BP and waveform measured invasively. METHODS: Healthy volunteers (n=53) served as subjects for the study. Blood pressures and waveforms obtained via a radial artery catheter (IABP) were compared with non-invasive measurements obtained every 12-15 beats by the new system (Vasotrac BP) from the opposite radial artery. In a sub-group of volunteers (n=11), BP was acutely increased and decreased with isoproterenol, phenylephrine and sodium nitroprusside. Data were analyzed by determining correlation and agreement between the two systems of measurement. Waveforms obtained by the two systems were qualitatively examined. RESULTS: Non-invasive BP measured every 12-15 beats by the Vasotrac correlated with IABP (systolic r2 = 0.89; diastolic r2 = 0.88; mean r2 = 0.94). The actual values obtained by the two methods agreed closely with > 90% of readings being within 2SDs when plotted by the Bland Altman method. This was also true during vasoactive drug infusion when BP changed acutely and swiftly. During this dynamic period, Vasotrac BP accurately tracked the changes in IABP with correlations (systolic r2 = 0.82; diastolic r2 = 0.89; mean r2 = 0.95) and close agreement (> 90% of readings were within 2 SDs in the Bland Altman plot). Waveforms displayed by the two systems were qualitatively very similar. Pulse rates measured by the two systems were identical. CONCLUSIONS: The Vasotrac system displayed an arterial waveform which was similar to that obtained directly and measured BP and pulse rate accurately. It should be a convenient device to measure BP continually in a non-invasive fashion.

Adult↗
PubMed1999

Differential diagnosis of thyroid crisis and malignant hyperthermia in an anesthetized porcine model.

The intra-operative differential diagnosis between thyroid crisis and malignant hyperthermia can be difficult. Also stress alone can trigger MH. The purposes of this study were: 1) to investigate the metabolic and hemodynamic differences between thyroid crisis and MH, 2) determine how thyroid crisis affects the development of MH, and 3) determine if the stress of thyroid crisis can trigger MH in susceptible individuals. We studied MH susceptible and normal swine. Two groups of animals (MH susceptible and normal) were induced into thyroid crisis (critical core hyperthermia, sustained tachycardia and increase in oxygen consumption) by pretreatment with intraperitoneal triiodothyronine (T3) followed by large hourly intravenous injections of T3. Two similar groups were given intravenous T3 but no pretreatment. These animals did not develop thyroid crisis and served as controls. Thyroid crisis did not result in metabolic changes or rigidity characteristic of an acute episode of MH. When the animals were subsequently challenged with MH triggering agents (halothane plus succinylcholine) dramatic manifestations of fulminant MH episodes (acute serious elevation in exhaled carbon dioxide, arterial CO2, rigidity and acidemia) were noted only in the MH susceptible animals. Although thyroid crisis did not trigger MH in the susceptible animals it did decrease the time to trigger MH (14.1 +/- 7.2 minutes versus 47.2 +/- 17.7 minutes, p < 0.01) in susceptible animals. Hormone induced elevations in temperature and possibly other unidentified factors during thyroid crisis may facilitate the triggering of MH following halothane and succinylcholine challenge.

Animals↗
PubMed1998

Double volume exchange transfusion for ABO incompatible liver transplantation in paediatric patients: intraoperative and preoperative approach.

Double volume blood exchange transfusions (DBVET) were used to reduce the serum antibody levels in six paediatric patients receiving ABO incompatible hepatic allografts. In four patients, the exchange transfusions took place on the ward prior to surgery. In three of these four patients who had titres measured, the anti-A IgM titres fell from 1024 to 64, 64 to 8, and 128 to 16, respectively. The anti-A IgG titres fell from 32 to 16 and 512 to 64 in two patients, but rose from 16 to 32 in the third. In two patients DBVET were performed intraoperatively using a rapid infusion device. The IgM titres fell from 256 to 32 and 64 to 1, respectively, and the IgG titres fell from 16 to 4 and 2 to 0. Intraoperative DBVET can acutely and effectively reduce blood group antibodies. Intraoperative DBVET may reduce graft ischaemia time and allow red blood cell salvage.

ABO Blood-Group System↗
PubMed1997

Combined liver-total bowel transplantation has no immunologic advantage over total bowel transplantation alone. A prospective study in a porcine model.

BACKGROUND: Rejection remains a major obstacle to successful bowel transplantation in humans. It has been suggested that a simultaneous liver transplant would shield the bowel graft from immunologic attack, but the liver shortage would be aggravated. In a preclinical model, we studied the influence of simultaneous liver grafting by comparing the incidence of early bowel rejection after combined liver-total (small- and large-) bowel transplants vs total bowel transplants alone. METHODS: We assessed the incidence of early post-transplant rejection, graft-vs-host disease, and infection after combined liver-total bowel transplants (group 1, n = 10) and total bowel transplants alone (group 2, n = 9) in outbred Yorkshire Landrace pigs. Liver and bowel grafts were transplanted orthotopically with portal vein drainage after recipient hepatectomy (group 1) and total enterectomy (groups 1 and 2). Posttransplant immunosuppression was performed with intravenous tacrolimus (whole blood levels, 15 to 30 ng/mL) and prednisolone. In groups 1 and 2, bowel biopsy specimens from the ileostomy were obtained daily. In group 1, liver biopsy specimens were obtained weekly. Rejection was graded according to a 4-point scoring system (none, mild, moderate, and severe). RESULTS: Overall graft survival at days 7, 14, and 21 was 89%, 44%, and 11%, respectively, in group 1 vs 100%, 100%, and 86%, respectively, in group 2 (P < .001). Death rates owing to (irreversible) rejection at days 7, 14, and 21 were 0% in groups 1 and 2 (P = .48). Grading of bowel rejection episodes, based on the results of daily biopsy specimens, was not significantly different between the groups whether on individual days or overall. In group 1, the incidence of liver rejection episodes was as high as 66% (day 14 and at autopsy). At autopsy, generalized graft-vs-host disease (skin, native intestine, and native liver) was noted in 55% of group 1 and 43% of group 2 pigs (P = .55). Graft-vs-host disease was noted concurrently with rejection episodes of the liver or bowel grafts. CONCLUSIONS: Simultaneous liver grafting did not further reduce the incidence of early bowel rejection or graft-vs-host disease when compared with total bowel transplants alone. Based on the results of this preclinical study, simultaneous liver grafting is not indicated for patients with short-bowel syndrome and normal liver function.

Animals↗
PubMed1996

Thermal response in acute porcine malignant hyperthermia.

This study was designed to evaluate how vital organ and skin-surface temperatures correlate with other clinical signs of a malignant hyperthermia (MH) episode. Six susceptible swine were anesthetized with thiopental and nitrous oxide and kept normothermic (approximately equal to 38 degrees C). After a 30-min control period, halothane (1 minimum alveolar anesthetic concentration) was administered, followed in 5 min by a bolus of succinylcholine (2 mg/kg intravenously). Monitoring included: 1) ETCO2; 2)PaO2, PaCO2, pHa; 3) cardiovascular function; 4) core temperatures (esophagus, pulmonary artery, and rectum); 5) organ temperatures (brain, kidney, liver, and four skeletal muscles); and 6) skin temperatures (forehead, neck, and axilla). Within 10 min after exposure to halothane and succinylcholine, all animals developed fulminant MH. Kidney, liver, and brain temperatures increased more rapidly than pulmonary artery temperature with the onset of MH. Temperatures significantly increased in the visceral organs prior to the detection of contractures within skeletal muscles. The masseter, longissimus dorsi, quadriceps, deltoid, and extensor digiti II intramuscular temperatures were 1-2 degrees C less than pulmonary artery and esophageal temperatures during the episodes, whereas those of the kidney, liver, and brain were the same or slightly greater. When it occurs, core hyperthermia during acute MH results largely from heat produced in central organs, not in skeletal muscle per se. In these swine, changes in axilla skin surface temperatures correlated well with core temperature trends, whereas those of the neck and forehead did not. Unless a skin-surface probe can be placed in close proximity to a major vessel, cutaneous temperatures should not be substituted for measurements at an appropriate core site.

Acute Disease↗
PubMed1996

Prior hypothermia attenuates malignant hyperthermia in susceptible swine.

This study was designed to determine the extent by which mild or moderate hyperthermia attenuates the triggering of malignant hypothermia (MH) induced by the combined administration of halothane and succinylcholine. Sixteen susceptible swine were initially anesthetized with nontriggering drugs and then either kept normothermic (approximately equal to 38 degrees C, n = 6) or cooled to induce mild (approximately equal to 35 degrees C, n = 6), or moderate (approximately equal to 33 degrees C, n = 4) hypothermia. Next, after a 30-min control period, the normothermic and mildly hypothermic animals were administered 1 minimum alveolar anesthetic concentration (MAC) halothane followed by a bolus dose of succinylcholine (2 mg/kg). Within 10 min all normothermic animals developed fulminant MH, whereas the onset of MH was slowed or was absent in the mildly hypothermic group. To test whether moderate hypothermia could more effectively minimize the signs of a MH episode, this group of animals was exposed to 1.5 MAC halothane followed 10 min later by a 3-mg/kg bolus of succinylcholine. MH was not induced and anesthesia was then changed to nontriggering drugs (ketamine and pancuronium). The animals were then aggressively rewarmed to 38 degrees C: a slight increase in the ETCO2 was detected, but MH episodes did not spontaneously occur. Subsequently, the readministration of halothane and succinylcholine rapidly provoked fulminant MH. We concluded that the induction of mild hypothermia impairs triggering and reduces the progression of MH induced by the combined administration of halothane and succinylcholine, whereas moderate hypothermia was completely protective and thus could be considered for prophylaxis.

Animals↗
PubMed1995

Comparison of the flow rates of central venous catheters designed for rapid transfusion in infants and small children.

Large-bore Hickman catheters are useful in infants and small children for the rapid transfusion of blood or fluids into the central circulation. Recently high-flow plastic sheaths have been developed for the same purpose. We compared the flow rates of normal saline, 5% albumin and packed red blood cells through two sizes of Hickman catheters that have been recommended for major surgery in infants to five sizes of Arrow plastic sheaths of comparable external diameters, and to 14 and 16 gauge Jelco catheters. The flow rates of all three solutions through the plastic sheaths and the 14 gauge Jelco catheters were superior to both sizes of Hickman catheters. Shortening the Hickman catheters improved their flow. High-flow plastic sheaths can provide a useful alternative to Hickman catheters in patients where permanent, large-bore central venous catheters are not required. Hickman catheters should be shortened as much as safely possible if massive haemorrhage is anticipated.

Catheterization, Central Venous↗
PubMed1995

Anaesthetic management of bone marrow transplant recipients less than two years of age.

The charts and anaesthetic records of 97 infants less than two years of age who underwent bone marrow transplantation at the University of Minnesota from 1978-1992 were retrospectively reviewed. These infants underwent 564 general anaesthetics. There were 48 perioperative complications, most (39) involving the airway. There were 20 difficult intubations occurring in 13 patients. The causes of the difficult intubations were anatomical abnormalities (12), mucositis (4), pharyngeal oedema (3) and emesis upon induction of anaesthesia (1). Four intraoperative deaths occurred. The deaths were caused by haemorrhage (2), pulmonary embolism (1) and myocardial ischaemia (1). Four patients died within 72 h of surgery; one from cerebral oedema following an intraoperative cardiac arrest, one from fungal septicaemia, one from haemorrhage and one from multiple organ failure following an intracerebral haematoma. Infants undergoing bone marrow transplantation are at high risk for perioperative morbidity and mortality, particularly from complications involving the airway, bleeding or sepsis.

Anesthesia, General↗
PubMed1994

Clinical assessment of the Augustine Guide for endotracheal intubation.

The Augustine Guide (AG) allows oral endotracheal intubations to be performed blindly; head and neck manipulation are unnecessary. It is a premolded device designed to fit in a lock and key fashion in the glottis, thus serving as a guide to allow blind laryngeal insertion of an endotracheal tube. Intubation success rate with the AG was studied in 100 adults intubated by the same individual; head and neck were held neutral. Intubations were described as easy if they were successful in the first attempt and difficult when more than one attempt to position the AG was necessary. Endotracheal intubation was successful 94% of the time and was easy in 71%. Repositioning of the AG was necessary in 23%. Patients with jaw abnormalities required repositioning more often (P < 0.05). Esophageal intubation did not occur. Minor trauma was noted in 18% of subjects. The AG is a safe and effective tool for blind orotracheal intubation.

Adolescent↗
PubMed1993

Long-term outcome of Hurler syndrome following bone marrow transplantation.

Previous reports suggested a therapeutic response of lysosomal storage diseases such as Hurler syndrome following bone marrow transplantation. However, a clearer understanding of outcome has awaited long-term follow-up. We evaluated prospectively 11 consecutive patients with Hurler syndrome receiving marrow from an HLA-identical sib donor between September 1983-October 1988. Follow-up evaluations included assessment of donor engraftment by restriction fragment polymorphism analysis, determination of leukocyte alpha-L-iduronidase level, measurement of lumbar cerebrospinal fluid (CSF) pressure, computerized tomography (CT) of the brain, and psychometric testing. In this series there was a survival rate of 9/11 (82%) with all survivors showing complete (7 patients) or partial (2 patients) donor engraftment. Prospective longitudinal evaluation of the 9 surviving children, now 3.8-8.9 years posttransplantation (median 5.5) demonstrated persistence of previously deficient leukocyte alpha-L-iduronidase at levels reflecting the donor genotype and degree of donor engraftment. Urinary glycosaminoglycan excretion declined to near-normal within 5 months of donor engraftment. Prior to treatment, 7 of 8 children studied were found to have occult intracranial hypertension (lumbar CSF pressure > 20 cm CSF); however, all surviving children attained normal or near-normal pressure within 18 months of donor engraftment. Longterm follow-up CT imaging of the brain did not show progressive volume loss (cerebral atrophy) after donor engraftment. Of 9 survivors, 4 children having a developmental quotient (DQ, Mental Development Index on Bayley Scales of Infant Development) above 80 prior to transplantation subsequently maintained IQ scores above this level. However, 5 patients with lower pretransplant DQ scores now have significant cognitive deficits and attention deficit hyperactivity disorder. Progressive brain damage resulting from communicating hydrocephalus may be prevented by successful engraftment. Early transplantation of children with Hurler syndrome who have normal intelligence is likely to have the clearest benefit because long-term intellectual outcome will be limited by brain damage which has occurred prior to treatment.

Bone Marrow Transplantation↗