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G D Puri

Publications and source records attributed to G D Puri.

44 records · Page 3Linked to original sources

A new site for the adjustable pressure limiting valve on a circle absorber.

A new site for the adjustable pressure limiting valve has been suggested which will result in the most efficient utilisation of soda lime using typical flows with a circle absorber system. It will permit economy of fresh gases using old models of circle absorbers in which the adjustable pressure limiting valve and fresh gas inlet are both situated upstream of the inspiratory unidirectional valve. The cost of the new attachment is small.

Equipment Design↗

Determination of ventilatory minute volumes for normocapnic ventilation under anaesthesia in healthy adults.

BACKGROUND: Mechanical ventilation under anaesthesia needs to be controlled to maintain normal oxygen and carbon dioxide tensions in the blood and to economize on fresh gas flows. Various ventilation nomograms such as Radford's nomogram and Nunn's CO2 predictor are based on data from studies, some of which do not mimic the conditions which prevail under anaesthesia. We, therefore, planned a study to formulate nomograms for normocapnic ventilation for anaesthetized adult subjects. METHODS: Two hundred and fifty-three patients with normal pulmonary function tests, scheduled for elective non-thoracic surgery were studied. Subjects were ventilated with a Siemens Servo 900 B ventilator using CO2 analyser 930 (Siemens-Elema Sweden) to adjust the minute volume sufficient to maintain end-tidal carbon dioxide fraction (FE,CO2) at around 5.5 normocapnia (PaCO2 5.06-5.6 kPa). This was confirmed with arterial blood gas analysis. RESULTS: The mean (SD) ventilation required for male patients was 6.123 (0.91) L [105 (13.1) ml/kg]. This was significantly higher than the requirement for female patients [5.262 (0.82) L; 98.7 (13.3) ml/kg]. The minute volume requirements showed a significant correlation with weight (W), height (H), body surface area, body mass index and other combinations of weight and height such as W x H, W/H, W2, W3 and H/W1/3. Nomograms were constructed for different weights and heights of males and females using multiple regression analysis. These minute volumes were found to be significantly higher than those calculated according to Radford's nomogram as well as Nunn's CO2 predictor and significantly lower than the Adelaide ventilation guide. CONCLUSION: The differences obtained in our nomograms are probably because the earlier ones were based on minute carbon dioxide production and physiological dead space data obtained from widely differing studies, some of which did not resemble conditions prevailing under anaesthesia. None of these used strict inclusion criteria such as pulmonary function tests. These may also be due to a difference in body structure between the subjects studied. Therefore, minute volume requirements calculated based on available western nomograms should not be applied to Indian subjects for normocapnic ventilation under anaesthesia.

Adolescent↗

Peri-operative management of patients for video assisted thoracoscopic thymectomy in myasthenia gravis.

Three patients of myasthenia gravis, who under went video-assisted thoracoscopic surgery (VATS) were given general anaesthesia by propofol infusion and muscle relaxation by atracurium infusion. Isoflurane was added to control depth of anaesthesia on the basis of haemodynamic changes during surgery. One lung ventilation (OLV) was achieved by placement of Carlens left sided double lumen bronchocatheter. Right-sided surgical approach was used to perform thymectomy. Contrary to claimed short duration of surgery, in first patient, OLV lasted for 10 hours 30 minutes and patient developed re-expansion pulmonary oedema. OLV in second and third patient was for six hours thirty minutes and three hours 45 minutes respectively. Morning dose of pyridostigmine was omitted and atracurium (0.1 mg/kg) was found to be satisfactory for intubation and relaxation was maintained with atracurium infusion to get desired monitored effect. We could not extubate our patients due to longer duration of surgery and the sequelae there off. Post-operative elective ventilation and spontaneous weaning off the atracurium effect was thus preferred.

Adult↗

Infection rates in single- and double-lumen central venous catheters in critically ill patients.

BACKGROUND: Catheter-related sepsis is a well known complication in critically ill patients receiving total parenteral nutrition. Micro-organisms may travel from the skin puncture wound along the external surface of the catheter or from the hub through the lumen of the catheter, to be shed into the circulation causing bacteraemia and sepsis. The incidence of sepsis is said to be about three times greater with multiple-lumen catheters than with single-lumen catheters. METHODS: Fifty patients admitted to our intensive care unit were randomly assigned to have either a single-lumen (Group I, 25 patients) or double-lumen (Group II, 25 patients) hydromer-coated, polyurethane central venous catheters of the same gauge and length, placed through the infraclavicular subclavian approach using the Seldinger technique. A sterile dry gauze dressing at the skin puncture site was changed every day. Skin swabs were taken for semi-quantitative culture studies before catheter insertion and removal, from the proximal 3 cm (lying subcutaneously) and distal 5 cm of the catheter segments on removal of the catheter, and venous blood was drawn from a peripheral vein before removal of the catheter. RESULTS: The most common isolate was coagulase negative Staphylococcus. No significant difference was found between the two groups in the incidence of catheter-related infection and catheter-related sepsis. CONCLUSION: Double-lumen central venous catheters placed in critically ill patients do not cause more sepsis than single-lumen catheters.

Adult↗

Perioperative myocardial infarction in coronary artery disease patients and 'at-risk' for coronary artery disease patients undergoing non-cardiac surgery.

BACKGROUND: Perioperative myocardial infarction (POMI) carries a high mortality and occurs more commonly in patients with a history of coronary artery disease (CAD). However, there are also other patients undergoing surgery who are 'at risk' for CAD but who do not have a history of infarction or angina. We compared the incidence of POMI in these two groups. METHODS: In a prospective study of 69 men and 39 women over 30 years of age undergoing non-cardiac surgery under general or regional anaesthesia, 56 had definite CAD and 52 were 'at-risk' for CAD. All these patients were followed up with serial postoperative electrocardiography and CK-MB isoenzyme analysis for the diagnosis of POMI. RESULTS: The POMI rate was 32% in definite CAD patients and 15% in patients 'at-risk' for CAD. Mortality in patients with POMI was 17% in those with CAD and 13% in those 'at-risk' for CAD. Perioperative myocardial infarction was maximal in the first 24 hours following surgery (77%). All the POMIs were painless. Anaesthesia techniques--whether regional or general--did not influence the incidence of POMI (Chi-square, p > 0.05). The type of drugs used in the treatment of CAD such as beta-blockers, calcium channel blockers and antiplatelet agents did not cause any difference in the incidence of POMI (Chi-square, p > 0.05). Patients who had either an intraoperative hypertensive episode, tachycardia, arrhythmias or ST-segment changes had a higher incidence of POMI (Chi-square, p > 0.05). The incidence of POMI was not lower in patients undergoing transurethral resection of the prostate compared to patients undergoing other types of non-cardiac surgery (Chi-square, p > 0.05). CONCLUSION: POMI occurs in one-third of patients with a history of CAD and one-sixth of those 'at-risk'. It carries a mortality of 17% and 13% respectively. Decisions to operate on such patients should be taken with caution.

Aged↗