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Biomedical subjects

D Malhotra

Publications and source records attributed to D Malhotra.

At least 55 records · Page 3Linked to original sources
PubMed1996

Fractional urea clearance in continuous ambulatory peritoneal dialysis: effects of volume disturbances.

The effects of volume disturbances on the KT/V were investigated prospectively in 133 consecutive urea clearance studies on patients on continuous ambulatory peritoneal dialysis (CAPD). Four subjects (group A) had fluid loss (actual weight < dry weight), 57 (group B) were studied on the basis of their dry weight, 58 (group C) had moderate fluid excess (0.5% of dry weight), and 14 patients (group D) had severe fluid excess (> 5% of dry weight). The KT/V was calculated on the basis of dry weight and actual weight with V obtained from the Watson anthropometric formulae which were applied either uncorrected or with a correction for changes in body water from dry weight conditions. The groups compared by variance analysis. The following weekly KT/V estimates were obtained: (1) using dry weight V: group A 1.81 +/- 0.17, group B 2.0 +/- 0.59, group C 1.79 +/- 0.46, group D 1.85 +/- 0.37 (no difference between groups); (2) using uncorrected actual weight V: group A 1.85 +/- 0.15, group B 2.05 +/- 0.59, group C 1.77 +/- 0.45, group D 1.78 +/- 0.37 (group B had a higher KT/V than group C, p < 0.05), and (3) using corrected actual weight V: group A 1.93 +/- 0.14, group B 2.05 +/- 0.59, group C 1.70 +/- 0.43, group D 1.63 +/- 0.36, (group B had a higher KT/V than either group C or group D, both at p < 0.01). In CAPD, fluid deficit is rare and causes a small increase in KT/V, whereas fluid retention is frequent and causes a decrease in KT/V. This decrease is pronounced in patients with severe fluid excess. The uncorrected Watson formulae underestimate V and, consequently, overestimate KT/V in CAPD patients with fluid excess.

Aged↗
PubMed1996

Estimated versus predicted creatinine generation as an indicator of compliance with the prescribed dose of continuous peritoneal dialysis.

The expression (Estimated-Predicted)/Predicted creatinine generation ¿(E-P)/P¿ has been proposed as an index of compliance in continuous peritoneal dialysis (CPD). We attempted to define an (E-P)/P value that can be used as a cut-off for non-compliance and to characterize the relation of (E-P)/P to serum albumin. In 324 clearance studies, (E-P)/P had a normal distribution with a mean of +0.094 and an SD of 0.357. In these studies, there was a weak correlation between (E-P)/P and serum albumin (r = 0.12, P < 0.05), but (E-P)/P was not a predictor of serum albumin by logistic regression. In 34 CPD patients, who had an increase in the dose of CPD resulting in an increase in measured creatinine clearance from 43.8 +/- 14.0 to 66.1 +/- 17.6 L/1.73 m2 weekly (P < 0.001), (E-P)/P increased correspondingly from +0.018 +/- 0.284 to +0.153 +/- 0.369 (P = 0.018), although all subjects should be in a steady state of creatinine excretion in the second study. The rise in (E-P)/P was statistically significant in the subgroup of 17 subjects who had a decrease in serum albumin, but not in the subgroup of 14 subjects who had an increase in serum albumin from the first to the second clearance study. The (E-P)/P cut-off for a definitive diagnosis of CPD non-compliance may be around +0.400 or +0.500. The findings of this study suggest that non-compliance, as indicated by (E-P)/P, has an adverse effect on serum albumin and that non-compliance increases after a prescribed increase in the dose of CPD.

Creatinine↗
PubMed1995

Tuberculous uteroenterocutaneous fistula--a rare post-caesarean complication.

A case of uteroenterocutaneous fistula which developed after lower segment Caesarean section is described. A total abdominal hysterectomy with removal of a tuboovarian mass with excision of the fistulous tract and repair of a small gut fistula were performed. The tuberculous aetiology of this fistula was established after surgery by a positive endometrial culture of acid fast bacilli and the demonstration of epithelioid granulomas in the surgical specimen. Antituberculosis therapy was started and the postoperative recovery was uneventful. The description of the nature of the fistula, its rarity and its presence in a woman with unimpaired fertility are discussed.

Adult↗
PubMed1995

Symptomatic fluid retention in patients on continuous peritoneal dialysis.

The clinical features, pathogenesis, management, prognosis, and predictors of symptomatic fluid gain (SFR) were analyzed for 71 episodes occurring in 66 patients on continuous peritoneal dialysis, 94.4% on continuous ambulatory peritoneal dialysis (CAPD) and 5.6% on continuous cycling peritoneal dialysis. Compared with a control group of 149 CAPD patients, the SFR group had a higher percentage of diabetics (64 versus 46%) and a higher frequency of noncompliance with fluid restriction (76 versus 22%), salt restriction (74 versus 23%), and performance of dialysis (30 versus 7%) (all at P < or = 0.015). Peripheral edema (100%), pulmonary congestion (80%), pleural effusions (76%), and systolic (83%) and diastolic (66%) hypertension were the most common manifestations of SFR. The annual hospitalization rate for SFR was 4.1 +/- 5.8 days per patient. SFR resulted in the discontinuation of CAPD in 10 patients and death in 1 patient. Serum sodium concentration was not different between dry and maximal weight in the SFR group. Thirty-eight (58%) of SFR and 61 (41%) of control patients were evaluated by peritoneal equilibration tests (PET). SFR patients had lower PET drain volume (2.08 +/- 0.47 versus 2.54 +/- 0.23 L) and a higher frequency of high peritoneal solute transport (32.2 versus 2.4%). In this group, logistic regression identified dietary noncompliance, low PET drain volume, and young age as independent predictors of SFR. Response to management and preventive measures was inconsistent. The best results were obtained by the use of short dwell exchanges with hypertonic dialysate in compliant patients with high peritoneal solute transport. SFR has serious consequences in CAPD. (ABSTRACT TRUNCATED AT 250 WORDS)

Diet, Sodium-Restricted↗
PubMed1995

The minimal dose of dialysis required for a target KT/V in continuous peritoneal dialysis.

This study attempted to define the minimal dose of dialysis needed to produce a target KT/V in continuous peritoneal dialysis (CPD). In a training set of 143 clearance studies performed in 92 CPD patients, logistic regression identified low urine volume (UV) and low dialysate drain volume normalized by body water (DV/V) as predictors of weekly KT/V urea < or = 1.70. Solution of the regression equation with UV fixed at 0.00 1/24 h and at different probabilities of low KT/V provided a series of minimal DV/V values consistent with weekly KT/V > or = 1.70 in anuria. The accuracy of the logistic regression model and of the DV/V cut-offs was tested in a validation set (VS) of 189 urea kinetic studies performed in another 102 CPD patients. In the VS, the area under the Receiver Operating Characteristic curve generated by the regression model was 0.832 (95% Confidence Interval: 0.798-0.866). The DV/V cut-off value of 0.301 per 24 h, calculated by solving the regression model at p = 0.442 and with UV = 0, identified studies with weekly KT/V < 1.70 with a sensitivity of 89.3% and a specificity of 78.1% in anuric VS subjects (n = 60). Use of only the first urea kinetic study from each patient did not modify the predictors of KT/V or the cut-off values derived from solution of the regression model. The DV/V cut-off of 0.324 per 24 h, derived from the logistic regression model predicting KT/V < or = 1.90, identified KT/V < 1.90 in VS anuric subjects with a sensitivity of 94.3% and a specificity of 81.0%. Low UV and DV/V predict low KT/V urea in CPD. Prescribed 24 h exchange volume in anuric CPD subjects should be calculated to produce DV/V values exceeding 0.301 1/24 h per 1 body water for a KT/V of 1.70 and 0.324 1/24 h per 1 body water for a target weekly KT/V of 1.90.

Creatinine↗
PubMed1994

Preterm breech delivery in a developing country.

OBJECTIVES: To determine if cesarean section offers any advantage over vaginal delivery for a preterm breech fetus in a developing country. METHODS: A retrospective analysis from hospital records was done at a tertiary care center in North India. Two hundred and twenty-four preterm breech deliveries (28-36 completed weeks) between January 1988 and December 1991 from a total of 13,149 deliveries at the hospital during this period formed the study group. Fetal death and lethal congenital malformations diagnosed antepartum were excluded. Intrapartum and neonatal morbidity and mortality in vaginal versus cesarean deliveries were the main outcome measures. RESULTS: Although the combined intrapartum and neonatal mortality was significantly higher for vaginal delivery (35.9% vs. 17.7%), there was no significant difference when the data was correlated with birthweight or gestational age. The neonatal morbidity was also similar in both these groups. In women with a poor obstetric history, the neonatal survival was better in the cesarean group (93% vs. 43%; P = 0.0004). CONCLUSION: Even with optimum neonatal care facilities, cesarean section does not offer any advantage over vaginal delivery for a preterm breech fetus in a developing country. The present study does not advocate the routine use of cesarean section for this group of fetuses. However, it is the preferred route of delivery for women with a poor obstetric history.

Adult↗
PubMed1994

Effect of hematocrit on dialyzer urea and creatinine clearance indices in a hemodialysis patient with erythrocytosis.

The association between azotemic index dialyzer clearances and hematocrit was investigated in a 63-year-old dialysis-dependent man with acquired renal cysts. During 43 months of hemodialysis, hematocrit rose from 27.3 to 65.0 vol%, as a consequence of high serum erythropoietin levels. Concomitantly, dry weight also increased from 116.8 to 140.8 kg. Both hematocrit and dry weight correlated with: (a) urea reduction ratio, (b) creatinine reduction ratio (CRR), and (c) KT/V urea. All correlations were negative. Stepwise regression showed that only hematocrit was an independent correlate of the CRR (CRR = 0.662 - 007* Hct, R2 = 0.770); whereas, both hematocrit (Hct) and weight (W) were independent correlates of KT/V urea (KT/V = 2.070 - 0.005*Hct - 0.009*W,R2 = 0.721). In addition to creatinine clearance, urea clearance through the dialyzer is reduced by a rising hematocrit. The effect of hematocrit on urea clearance is relatively small. Therefore, it requires large changes in hematocrit in order to be detected.

Creatinine↗
PubMed1994

Volume of distribution and fractional clearance of urea in amputees on continuous ambulatory peritoneal dialysis.

OBJECTIVES: To demonstrate the effects of amputation on the estimates of urea volume of distribution (V) and KT/V urea in continuous ambulatory peritoneal dialysis (CAPD) patients and to present a method for correcting the errors created by the uncorrected anthropometric formulas estimating V. DESIGN: (1) A mathematical analysis of the error and the correction proposed was performed. (2) Urea kinetic modeling with uncorrected and corrected estimates utilizing both the Watson and the Hume anthropometric formulas was performed in amputees on CAPD. SETTING: Subjects were recruited from four dialysis units in one city: one Veterans Affairs unit, one university-affiliated unit, and two community units. PATIENTS: Fourteen amputees on CAPD:12 with unilateral leg amputation and 2 with bilateral leg amputation, at the same length of the leg, were studied. INTERVENTIONS: Urea kinetic studies were performed in 24-hour drained dialysate and urine specimens. MAIN OUTCOME MEASURES: Uncorrected and corrected estimates of V and KT/V urea were compared to each other and to the predictions of the mathematical model. Body weights corresponding to uncorrected and corrected V estimates were compared to the actual body weights. RESULTS: (1) The mathematical model predicts that uncorrected estimates by the anthropometric formulas will falsely characterize unilateral amputees as leaner than they are and bilateral amputees as more obese than they are. (2) In unilateral amputees studied with the Watson formulas, uncorrected V was 0.546 +/- 0.023 L/kg and corrected V was 0.520 +/- 0.023 L/kg (p < 0.001). Corresponding weekly KT/V urea values were 1.97 +/- 0.14 and 2.07 +/- 0.14, respectively (p < 0.001). Similar results were obtained with the Hume formulas. In bilateral leg amputees studied with the Watson formulas, uncorrected V was 0.479 +/- 0.022 L/kg and corrected V was 0.514 +/- 0.023 L/kg. Corresponding KT/V estimates were 2.11 +/- 0.45 and 1.96 +/- 0.14, respectively. The differences were even greater with the Hume formulas. Estimates of body weight calculated from corrected V values were equal to actual weight measurements, whereas those calculated from uncorrected V values were lower than actual body weight measurements in unilateral amputees, and much higher than actual body weight measurements in bilateral amputees. CONCLUSION: Uncorrected anthropometric estimates falsely characterize unilateral amputees as leaner than they actually are and bilateral amputees, amputated at the same leg length, as more obese than they actually are. Uncorrected KT/V estimates are, therefore, falsely low in unilateral amputees, and falsely high in bilateral amputees. The proposed correction of the anthropometric formulas provides estimates agreeing closely with dietary estimates of body composition. Further studies are needed to define the accuracy of the corrected formulas.

Aged↗
PubMed1993

Hypoxia and metabolic acidosis in the isolated heart: evidence for synergistic injury.

Although hypoxia and metabolic acidosis have both been shown to impair cardiac function, some workers have suggested that acidosis during a period of hypoxia will actually accelerate physiologic recovery from this insult. To address the interactions of metabolic acidosis and hypoxia further, isolated isovolumic rat hearts were exposed to normal perfusion conditions for 30 min to establish baseline conditions, then either continued normal conditions, metabolic acidosis, hypoxia, or combined acidosis and hypoxia for 30 min and subsequently reperfused under normal perfusion conditions for an additional 30 min. We observed that acidosis + hypoxia impaired recovery of cardiac contraction more than acidosis or hypoxia alone following experimental perfusion. The combination of acidosis and and hypoxia also impaired cardiac energy metabolism more than acidosis or hypoxia alone as assessed by increases in tissue inorganic phosphate during experimental perfusion as well as during reperfusion. These data suggest that during hypoxia, acidosis appears to primarily impair cardiac energy production as we have previously observed in the normoxic isolated rat heart. Therefore, in the intact beating heart, acidosis may not protect from hypoxic injury as has been suggested in simpler systems but may not protect from hypoxic injury as has been suggested in simpler systems but rather may exacerbate at.

Acidosis↗
PubMed1991

Contractile dysfunction during metabolic acidosis: role of impaired energy metabolism.

To investigate the mechanisms by which acidosis depresses cardiac function, a Langendorff isolated perfused rat heart preparation was studied using 31P magnetic resonance spectroscopy. Isolated hearts were subjected to normal perfusion conditions or experimental manipulations simulating severe metabolic acidosis, substrate depletion, impairment of oxidative metabolism, or low perfusate calcium concentrations. All maneuvers resulted in marked reductions in oxygen consumption and the force of myocardial contraction (dP/dt). Metabolic acidosis had bioenergetic changes suggestive of impaired energy production, specifically, increases in Pi and decreases in phosphocreatine concentrations, which did not occur in hearts subjected to low perfusate calcium concentrations. In acidotic perfusions as well as substrate depletion and impairment of oxidative metabolism, the change in dP/dt correlated best with the change in the intracellular concentration of monovalent Pi (P(im)) (r = 0.70, P less than 0.01), whereas in hearts subjected to a low perfusate calcium concentration, there was no relationship between dP/dt and the change in Pim concentrations. More detailed analysis of the time course of the metabolic and physiological changes with metabolic acidosis revealed a discordance between changes in Pim and the decreases in dP/dt during the first 20 min of the induction of acidosis and the first 10 min of recovery from acidosis. These data suggest that metabolic acidosis has a major direct effect on energy metabolism in this model. Moreover, impairment of oxidative metabolism in concert with decreases in intracellular pH may be important in the contractile failure associated with prolonged metabolic acidosis.

Acidosis↗
PubMed1991

Nuclear magnetic resonance spectroscopy in patients with anion-gap acidosis.

Proton nuclear magnetic resonance spectroscopy was performed on blood or urine from five patients with an anion-gap metabolic acidosis. In all of these cases, this methodology allowed the rapid and specific diagnosis of the nature of the metabolic acidosis. In several of these patients, spectroscopic evidence for intoxication with toxic alcohols was obtained. On the basis of these preliminary data, proton nuclear magnetic resonance spectroscopy may be a useful technique in the evaluation of patients with anion-gap acidosis.

Acid-Base Equilibrium↗
PubMed1990

Evaluation of the double-quantum filter for the measurement of intracellular sodium concentration.

Evaluation of the double-quantum filter for sodium was performed on several sample series of bovine serum albumin in water. Both single-quantum (1Q) and double-quantum (2Q) measurements were obtained. The quality of the 2Q filter was found to be quite sensitive to pulse width setting. Ordinary 1Q measurements of sodium in albumin-containing solutions show 100% visibility. At high ionic strengths, the 2Q albumin results confirm earlier conclusions demonstrating the tendency for the albumin molecule to unfold under a variety of influences. At physiological sodium concentrations, the magnitude of the 2Q/1Q ratio is controlled not only by the concentration of albumin, but also by the solution pH. Non-zero, double-quantum signals were observed in physiological samples consisting of essentially intracellular material (packed red blood cells) as well as in extracellular material (plasma and urine). Measurements in human urine showed no 2Q signal. However, high-concentration NaCl solutions did produce real, measurable 2Q signals. Therefore, the 2Q filter does not measure intracellular sodium exclusively. Although packed red blood cells gave the highest 2Q/1Q ratio (8.5 x 10(-3), plasma gave a very considerable 2Q/1Q ratio (2.3 x 10(-3). Because of its relatively high extracellular concentration, extracellular sodium may give a greater absolute 2Q signal than intracellular sodium in unmodified tissue samples. Based on these data, we conclude that a 2Q filter will not provide a useful measurement of intracellular sodium in in vivo tissue samples.

Erythrocytes↗
PubMed1985

Slipped upper femoral epiphysis and primary juvenile hypothyroidism.

The pathogenesis of slipped upper femoral epiphysis is unknown but the condition has been linked with various endocrine disorders. Nine patients with slipped epiphyses in association with primary juvenile hypothyroidism are presented. In all patients, slipping occurred or symptoms developed in the affected hip before the hypothyroidism was diagnosed. A generalised pathology was suggested by the absence of trauma (8 patients), by bilateral slipping (6 patients), and by obesity and short stature in all patients. All cases had delayed skeletal maturation and characteristic metaphysial changes were seen on their radiographs. The clinical diagnosis of juvenile hypothyroidism can be difficult but it merits consideration in patients who have a slipped upper femoral epiphysis in association with short stature, obesity, delay in skeletal maturity, or any one of these.

Adolescent↗
PubMed1984

Valgus deformity of the ankle in children with spina bifida aperta.

Valgus deformity of the hindfoot can occur at the subtalar joint, the ankle joint, or at both sites. In children suffering from spina bifida, the ankle is often the main site of deformity. Thirty-five ankles with valgus deformity of the hindfoot were studied in 23 children with spina bifida. A radiological triad was observed in all patients: shortening of the fibula, lateral wedging of the distal tibial epiphysis, and lateral tilt of the talus at the ankle mortise . There was a definite correlation between the severity of wedging and the degree of talar tilt, and a fair correlation between the severity of wedging and the extent of fibular shortening. The results of operation in 12 feet are presented. It is concluded that any operations performed below the ankle on these patients (subtalar fusion or triple arthrodesis) is unlikely to succeed; the deformity needs to be corrected above the ankle (by epiphysiodesis or supramalleolar osteotomy). Radiological assessment of the ankle by taking weight-bearing films in the anteroposterior plane is essential to determine the true extent of the deformity before undertaking any operation.

Adolescent↗