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Biomedical subjects

R Chawla

Publications and source records attributed to R Chawla.

At least 19 recordsLinked to original sources
PubMed2000

Global myocardial revascularization without cardiopulmonary bypass using innovative techniques for myocardial stabilization and perfusion.

BACKGROUND: In off-pump coronary bypass grafting (CABG), invasiveness is reduced but technically perfect anastomosis is jeopardized by cardiac motion and the need to hurry to reduce the time of ischemia. Also, a major cause of postoperative morbidity and mortality is ungrafted circumflex coronary artery disease. We have devised a means of overcoming these shortcomings and performing multivessel CABG. The objective of this study was to assess the safety and efficacy of our technique. METHODS: One hundred patients with severe triple-vessel disease underwent multivessel off-pump CABG. For cardiac stabilization, a combination of local pericardial stabilization sutures and lifting and rotating the heart by means of posterior pericardial sutures were used. For myocardial perfusion, a technique of retrograde coronary sinus perfusion by arterial blood from the ascending aorta was used. RESULTS: Each patient received an average of 3.8 grafts (range 3 to 5). Complications included conversion to cardiopulmonary bypass (CPB) in 1 patient and a perioperative myocardial infarction in the same patient. In all other patients we were able to perform a satisfactory grafting in all territories with no operative mortality. Rapid recovery allowed 95% of our patients to resume normal activity within 1 month. A predischarge graft angiogram in 35 patients showed 97.8% patency. CONCLUSIONS: These results suggest that off-pump CABG with our techniques is effective and safe. Early clinical outcome and excellent patency rates suggest its more widespread use in selected cases.

Adult↗
PubMed1998

Asymptomatic methaemoglobinaemia and its implications.

Anaesthetists are well trained to detect subtle skin signs of life-threatening situations such as cyanosis in hypoxia. However, cyanosis resulting from drug-induced, asymptomatic methaemoglobinaemia is rare and is likely to go undetected preoperatively. Patients presenting with asymptomatic methaemoglobinaemia may, therefore, offer a dramatic challenge to the unprepared anaesthetist. We report a case of methaemoglobinaemia secondary to dapsone ingestion that was diagnosed intraoperatively.

Cyanosis↗
PubMed1992

Acute isoniazid poisoning.

We present two cases of acute isoniazid poisoning in patients who ingested 7.5 g and 5.0 g of isoniazid respectively, with the intention of committing suicide. Both were admitted unconscious, with ventilatory insufficiency and convulsions. Hepatic dysfunction and peripheral neuropathy were notable complications.

Acute Disease↗
PubMed1992

Can pulse oximetry be used to measure systolic blood pressure?

This study evaluates the use of pulse oximetry to accurately monitor systolic arterial blood pressure in 100 healthy volunteers. Determination of arterial blood pressure using oximetry was made at the disappearance of visual display upon blood pressure cuff inflation, at the reappearance of visual display upon cuff deflation, and by averaging the two. The blood pressures obtained by pulse oximetry were compared with the arterial blood pressures obtained by Korotokoff sounds and noninvasive blood pressure equipment. Good agreement was obtained when the average of oximetry-based systolic blood pressure estimates at the disappearance and reappearance of the waveform were compared with Korotokoff sound pressures and noninvasive equipment pressures. Thus pulse oximetry can be used to measure systolic arterial blood pressure. This technique is specifically important for patients with Takayasu's syndrome (pulseless disease) where conventional techniques often fail to monitor systolic arterial blood pressure.

Adult↗
PubMed1990

Management of conjoined twins.

A case of thoracopagus conjoined twins encountered in the second stage of labor is presented. Delivery was possible by the vaginal route after reducing the fetal bulk by destructive operations. Problems in obstetric management of these cases are discussed and the importance of proper antenatal evaluation is stressed.

Adult↗
PubMed1990

Nitrobenzene poisoning and spurious pulse oximetry.

The successful management of nitrobenzene poisoning in a 21-year-old patient is presented. We report our experience of ventilatory care with additional intravenous methylene blue and ascorbic acid therapy. Pulse oximeters available at present are not useful in patients treated with methylene blue and should be used cautiously in the presence of cyanosis of unknown aetiology.

Adult↗
PubMed1989

Inter-alpha-trypsin inhibitor. Inhibition spectrum of native and derived forms.

The conversion of inter-alpha-trypsin inhibitor (I alpha I) into active, acid-stable derivatives by proteolytic degradation has been tested with 10 different proteinases. Of these, only plasma kallikrein, cathepsin G, neutrophil elastase, and the Staphylococcus aureus V-8 proteinase were found to be effective, each releasing more than 50% of this activity. However, a strong correlation between inhibitor degradation and significant release of acid-stable activity could only be found with the V-8 enzyme. Inhibition kinetics for the interaction of native I alpha I, the inhibitory fragment released by digestion with S. aureus V-8 proteinase, or the related urinary trypsin inhibitor, with seven different proteinases indicated that all had essentially identical Ki values with an individual enzyme and, where measurements were possible, nearly identical second order association rate constants. Significantly, none of the five human proteinases tested, including trypsin, chymotrypsin, plasmin, neutrophil elastase, and cathepsin G, would appear to have low enough Ki values to be physiologically relevant. Thus, the role of native I alpha I or its degradation products in controlling a specific proteolytic activity is still unknown.

Alpha-Globulins↗
PubMed1989

Fiberbronchoscopy in smear-negative miliary tuberculosis.

Twenty-two patients with smear-negative miliary tuberculosis underwent fiberbronchoscopy and brush smears; bronchial aspirates and transbronchial lung biopsy specimens were obtained. A definite diagnosis of tuberculosis was made in 16 (73 percent) patients. A rapid diagnosis was established in 14 of these 16 patients either from brush smears alone (three) or bronchial aspirate smear alone (one) or exclusively by histopathologic study of biopsy specimens (seven). Both brush smears and biopsy histopathology results provided the diagnosis in three patients. Bronchial aspirate culture was the only positive specimen in two patients. No serious complication resulted from the procedure. Our experience substantiates previous reports of the value and safety of fiberbronchoscopy in the rapid diagnosis of smear-negative miliary tuberculosis.

Biopsy↗
PubMed1989

Efficacy & dose-response of intrathecal pentazocine for post-operative pain relief.

With a view to assess the efficacy of intrathecal pentazocine for post-operative pain relief, 60 patients randomly divided into 6 equal groups were administered graded doses (0, 1, 2, 3, 4 and 5 mg respectively) of pentazocine lactate, intrathecally along with 1 per cent bupivacaine. The duration of analgesia was found to be dose related till 3 mg. Higher doses did not increase the duration of analgesia nor were any untoward effects observed. It is concluded that intrathecal pentazocine is safe and effective for post-operative pain relief and 3 mg is the minimum effective dose without side effect.

Adolescent↗
PubMed1988

Fibreoptic bronchoscopy in smear-negative pulmonary tuberculosis.

Fifty smear-negative pulmonary tuberculosis patients underwent fibreoptic bronchoscopy. Bronchial aspirate smears of twelve patients and post-bronchoscopic sputum smears of fourteen patients were positive for acid-fast bacilli (AFB). Bronchial biopsy provided the diagnosis in 9 out of 30 patients. Brush smears were positive in 28 patients, being the only positive sample in ten cases. A high yield from brush smears was obtained due to their preparation from caseous material wherever visible in the bronchi. With these results a rapid diagnosis was established in 36 of the 50 patients. When culture results were available, a definite diagnosis of tuberculosis was made in 45 of the patients. The yield from brush smears was found to be significantly better when compared to bronchial aspirate smears (p less than 0.01) and post-bronchoscopic sputum smears (p less than 0.01).

Adult↗