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Biomedical subjects

V Niranjan

Publications and source records attributed to V Niranjan.

8 recordsLinked to original sources

Spinal muscular atrophy type 1: A noninvasive respiratory management approach.

STUDY OBJECTIVE: To determine whether spinal muscular atrophy (SMA) type 1 can be managed without tracheostomy and to compare extubation outcomes using a respiratory muscle aid protocol vs conventional management. DESIGN: A retrospective cohort study. METHODS: Eleven SMA type 1 children were studied during episodes of respiratory failure. Nine children required multiple intubations. Along with standard treatments, these children received manually and mechanically assisted coughing to reverse airway mucus-associated decreases in oxyhemoglobin saturation. Extubation was not attempted until, most importantly, there was no oxygen requirement to maintain oxyhemoglobin saturation greater than 94%. After extubation, all patients received nasal ventilation with positive end-expiratory pressure. Successful extubation was defined by no need to reintubate during the current hospitalization. RESULTS: Two children have survived for 37 and 66 months and have never been intubated despite requiring 24-h nasal ventilation since 5 and 7 months of age, respectively. One other child underwent tracheostomy for persistent left lung collapse and inadequate home care, another for need for frequent readmission and intubation, and one child was lost to follow-up 3 months after successful extubation. The other six children have been managed at home for 15 to 59 (mean 30.4) months using nocturnal nasal ventilation after an episode of respiratory failure. The nine children were successfully extubated by our protocol 23 of 28 times. The same children managed conventionally were successfully extubated 2 of 20 times when not using this protocol (p < 0.001 by the two-tailed Fisher's Exact t Test). CONCLUSION: Although intercurrent chest colds may necessitate periods of hospitalization and intubation, tracheostomy can be avoided throughout early childhood for some children with SMA type 1.

Child, Preschool↗

Noninvasive management of pediatric neuromuscular ventilatory failure.

OBJECTIVE: To evaluate the use of mouth piece/nasal intermittent positive-pressure ventilation (IPPV) as an alternative to intubation or to permit extubation for patients with primarily neuromuscular ventilatory impairment and no ventilator-free breathing ability. DESIGN: A case control study. INTERVENTIONS: Using a protocol in which oxyhemoglobin desaturation was prevented or reversed by the continuous use of noninvasive IPPV and manually and mechanically assisted coughing as needed, patients with neuromuscular ventilatory failure and no ventilator-free breathing ability were managed noninvasively or extubated to continuous use of noninvasive IPPV for ventilatory support on room air. MEASUREMENTS AND MAIN RESULTS: Four of ten patients who presented in acute ventilatory failure were managed without intubation, despite becoming dependent on continuous ventilator use. The six intubated patients were extubated successfully to continuous noninvasive IPPV once normal arterial oxygen saturation levels could be maintained on room air, despite their having no ventilator-free breathing ability. CONCLUSIONS: The use of inspiratory and expiratory aids can decrease the need for intubation for patients with neuromuscular ventilatory failure in the absence of significant lung disease. It can also permit extubation, despite the need for continuous ventilatory support and, thereby, decrease the need to resort to tracheostomy.

Acute Disease↗

Glycemic control and cardiopulmonary function in patients with insulin-dependent diabetes mellitus.

BACKGROUND: We studied cardiopulmonary function during exercise in young subjects with long-standing insulin-dependent diabetes mellitus (IDDM) who have no clinical cardiopulmonary disease to determine the relationships of aerobic capacity, gas exchange, ventilatory power requirement, and cardiac output to chronic glycemic control. METHODS: Eighteen subjects with IDDM and 14 normal control subjects were studied. Nine diabetic subjects received twice daily insulin injections and had chronically elevated levels of glycosylated hemoglobin (hyperglycemic group); 9 other diabetic subjects received insulin via continuous infusion pumps and maintained chronic near-normal levels of glycosylated hemoglobin (normoglycemic group). At the end of at least 7 years of regular follow-up, aerobic capacity was determined by cycle ergometry. Lung volume, diffusing capacity, and cardiac output during exercise were measured by a rebreathing technique. Ventilatory power was measured by the esophageal balloon technique. RESULTS: Maximal work load and oxygen uptake were markedly impaired in chronically hyperglycemic diabetic patients associated with significant restrictions of lung volume, lung diffusing capacity, and stroke index during exercise. Membrane diffusing capacity was significantly reduced at a given cardiac index. The normoglycemic patients consistently showed less impairment than the hyperglycemic patients. CONCLUSION: Physiologically significant cardiopulmonary dysfunction develops in asymptomatic patients with long-standing IDDM. Chronic maintenance of near-normoglycemia is associated with improved cardiopulmonary function.

Adult↗

Systemic hypertension induced by hepatic overexpression of human preproendothelin-1 in rats.

Endothelin-1 (ET-1) has been implicated in the regulation of vascular tone in various pathological conditions. To examine the effect of in vivo overexpression of the peptide in rats, we prepared recombinant adenovirus stocks encoding the human preproET-1 cDNA (Ad.ET-1) or Escherichia coli lacZ (Ad.betaGal), each driven by cytomegalovirus early promoter. Ad.ET-1 or Ad.betaGal was injected into the caudal vein of rats and the animals were studied under anesthesia 96 h later. Hepatic overexpression of the virus-derived human ET-1 mRNA was accompanied by a 13-fold elevation of liver ET-1 content in the Ad.ET-1 group. Circulating plasma ET-1 levels in the Ad.ET-1 group were sixfold higher than those in the Ad.betaGal group. Mean arterial blood pressure was increased by 28 mmHg in the Ad.ET-1 group as compared with the Ad.betaGal group. In the Ad.ET-1 group, intravenous infusion of the ET(A) receptor antagonist FR 139317 reduced the blood pressure to levels seen in the Ad.betaGal group, whereas the same antagonist did not significantly alter the blood pressure in the Ad.betaGal group. Intravenous infusion of the ET(B) receptor antagonist BQ-788 caused a small but significant increase in blood pressure in both groups. These findings demonstrate that endogenous overexpression of preproET-1, accompanied by an elevation of plasma ET-1 concentrations to the levels seen in pathophysiological states, can cause systemic hypertension through the activation of the ETA receptor.

Adenoviruses, Human↗

Tracheal agenesis.

Explore the source record for details and available documents.

Adult↗

The current practice patterns of mechanical ventilation for respiratory failure in pediatric patients.

OBJECTIVE: To quantify the current practice patterns of mechanical ventilation for respiratory failure in pediatric patients. DESIGN: Mail survey using 2 hypothetical case studies sent to pediatric critical care physicians. MEASUREMENTS AND MAIN RESULTS: The required arterial blood gas (ABG) on conventional mechanical ventilation (CMV) is pH = 7.25 to 7.29, PO2 = 50 to 59 torr, O2 saturation = 0.85 to 0.89. Most of our survey participants will treat a patient failing conventional mechanical ventilation in their pediatric intensive care units (PICUs) with inverse ratio ventilation (IRV) (95%) and with high-frequency oscillatory ventilation (HFOV) (92%). CONCLUSION: Most of the surveyed pediatric critical care physicians practice permissive hypercapnia in the treatment of their patients who receive ventilatory assistance. More than 90% of surveyed pediatric critical care physicians are presently using inverse ratio ventilation and high-frequency oscillatory ventilation. These data suggest that these innovative modes of therapy are already accepted as part of the standard therapeutic spectrum by the surveyed group of physicians.

Blood Gas Analysis↗

A study of thyrotropin-releasing hormone for the treatment of spinal muscular atrophy: a preliminary report.

OBJECTIVE: To determine whether thyrotropin-releasing hormone (TRH) can increase muscle strength in children with spinal muscular atrophy types 2 and 3. DESIGN: A randomized, double-blinded, controlled, 5-wk drug trial of six subjects and three controls. Subjects and controls ranged from 4 to 8 yr of age and were randomly assigned to treatment and placebo groups in a ratio of 2:1. TRH (protirelin) or placebo was delivered intravenously through percutaneous intravenous catheters at a dose of 0.1 mg/kg (in 50 ml of normal saline) for a total of 29 days. Patients were evaluated using electromyography and handheld dynamometry of the deltoids, biceps, triceps, wrist extensors, hip flexors, quadriceps, hamstrings, and grip strength before and immediately after 5 wk of treatment. A unidirectional t test was used to compare mean values. RESULTS: Dynamometry improved significantly only for the six treated subjects (P < 0.02). Peroneal nerve conduction velocities were significantly faster in the treatment group (paired t test, P = 0.036). The parents of the treated children also provided anecdotal evidence of improvements in function. Improvements lasted 6-12 mo. CONCLUSIONS: TRH may be a useful treatment for spinal muscular atrophy. A larger, crossover design group comparison study is warranted.

Action Potentials↗