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Biomedical subjects

N Soni

Publications and source records attributed to N Soni.

At least 91 records · Page 5Linked to original sources

Septic atrial thrombus. A complication of central venous catheterisation.

A 77-year-old man underwent repair of a vesicocolic fistula following which he had a protracted stay in the intensive care unit due to recurrent septicaemia, which was initially caused by bowel anastomosis breakdown. Management included central venous cannulation and pulmonary artery catheter monitoring. A septic, mobile right atrial thrombus developed, which was successfully treated. The literature on this condition is reviewed.

Aged↗

C-reactive protein as a diagnostic test of sepsis in the critically ill.

Changes in the plasma concentration of C-reactive protein were assessed as a diagnostic test for sepsis in critically ill patients. Forty-nine episodes of secondary sepsis were identified in 31 patients. In 43 out of the 49 episodes there was a 25% or greater change in the concentration of C-reactive protein on the day that sepsis was diagnosed but in six episodes of sepsis the change was less than 25%. A 25% rise in the plasma concentration of C-reactive protein in the absence of other non-infective causes of a raised C-reactive protein, such as inflammation, tissue injury or surgery, is highly suggestive of infection, but failure of the C-reactive protein to rise does not eliminate a diagnosis of sepsis.

Bacterial Infections↗

Plasma neopterin as an adjunct to C-reactive protein in assessment of infection.

C-reactive protein (CRP) concentrations are increased in plasma in people with inflammatory conditions and bacterial infections. Plasma neopterin concentrations are increased in people with bacterial septicemias, viral infections, and graft vs host disease. Plasma concentrations of CRP and neopterin were measured daily in 21 bone-marrow transplant (BMT) patients, 64 patients in intensive-care units (ICU), and 12 patients with squamous cell carcinoma of the head and neck (HN). In the BMT patients, plasma neopterin measurements in addition to CRP measurements allowed infectious episodes to be distinguished from graft vs host disease. In the ICU patients, increased concentrations of CRP were not specific for infection and the additional plasma neopterin measurements did not improve this specificity. In all three patient groups, the derivation of a neopterin/CRP ratio was of no clinical use. These three groups of patients showed patterns of CRP and neopterin concentrations characteristic of their underlying diseases, the BMT patients with the immunological activation of graft vs host disease showed predominantly increased concentrations of plasma neopterin, ICU patients with infectious and inflammatory conditions had increased concentrations of both CRP and neopterin in plasma, and the HN group with localized inflammation showed increased plasma concentrations of CRP without increases in neopterin.

Adolescent↗

The Bain, ADE, and Enclosed Magill breathing systems. A comparative study during controlled ventilation.

The Enclosed Magill, Humphrey ADE and the Bain breathing systems are all used for controlled ventilation of the lungs. This study compares the three systems in vitro with a lung model and in clinical practice. No difference was observed, with ventilatory variables commonly used in clinical practice, between the Bain and the ADE, while significantly lower end-tidal carbon dioxide values were observed with the Enclosed Magill (about 7%). Lower fresh gas flows can be used under these circumstances to maintain normocapnia with the Enclosed Magill than either the Bain or the Humphrey ADE.

Adult↗

Comparison of the Magill and Lack anaesthetic breathing systems in anaesthetized patients.

The Magill and Lack anaesthetic breathing systems were compared by measuring inspired and expired carbon dioxide concentrations and expired minute volumes in lightly anaesthetized, unstimulated subjects. There were no significant differences between the two breathing systems at fresh gas flow rates of approximately 50 and 70 ml kg-1 min-1. Inspired carbon dioxide concentrations increased in one of six subjects at the higher fresh gas flow rate using the Magill system and in two using the Lack system. Inspired carbon dioxide concentration did not increase in only one of six subjects at the lower fresh gas flow rate with both systems. Expired carbon dioxide concentrations and expired minute volume increased in the majority of subjects at both fresh gas flow rates using each system. We conclude that a fresh gas flow rate greater than 70 ml kg-1 min-1 (which approximated to alveolar minute volume in our subjects) should be supplied to the Magill and Lack breathing systems.

Adult↗

Effects of pipecuronium and pancuronium on the isolated rabbit heart.

We have studied the effects of pipecuronium and pancuronium on myocardial contractility and heart rate in two different animal preparations. Pipecuronium and pancuronium produced no change in isometric contraction of rabbit atria. The chronotropic effects of pipecuronium, pancuronium and vecuronium were investigated using acetylcholine as an agonist in isolated perfused rabbit heart. Pancuronium but not pipecuronium or vecuronium, produced a significant degree of antagonism to the bradycardia produced by acetylcholine.

Androstane-3,17-diol↗

A comparison of anaesthetic breathing systems during spontaneous ventilation. An in-vitro study using a lung model.

Five anaesthetic breathing systems (Magill, Lack, Humphrey ADE, enclosed Magill and Bain) were compared using spontaneous ventilation in a simple lung model. The fresh gas flow at which rebreathing occurred was determined for each system by the application of four modified definitions of rebreathing. Two were based on the measurement of minimum inspired and two on end-expired carbon dioxide. The four A systems performed similarly with each individual definition. The rebreathing points found for each individual breathing system differed markedly between definitions, with those determined by the minimum inspired CO2 occurring at low, and probably misleading, FGF/VE ratio. The Bain system demonstrated rebreathing at considerably higher fresh gas flows whichever definition was used.

Anesthesiology↗

Anaesthesia and substance abuse.

Current practices in the abuse of illicit drugs in the United Kingdom are described with particular reference to their pathological effects and the implications for anaesthesia. Practical guidelines are given for the anaesthetic and peri- and postoperative management of addicts.

Anesthesia↗

The influence of CO2 production and physiological deadspace on end-tidal CO2 during controlled ventilation: a study using a mechanical model.

A mechanical lung model was used to investigate the effect of varying carbon dioxide production and deadspace on the end-tidal carbon dioxide levels achieved during mechanical ventilation when using the Bain, Humphrey ADE, and circle systems. Both factors had significant influence on end-tidal carbon dioxide concentration and could result in values in excess of those considered acceptable in clinical practice. The implications of the results are discussed.

Anesthesia, Closed-Circuit↗

Effect of rate of injection on the neuromuscular block produced by vecuronium.

A subparalytic dose (0.015 mg/kg) of vecuronium bromide was administered to matched pairs of patients undergoing routine dental surgery under enflurane-nitrous oxide/oxygen anesthesia either as a rapid bolus injection or as a slow infusion over 5 min. It was demonstrated that bolus injection produced peak plasma levels of drug considerably greater than those following slow infusion. Time to maximum block was more rapid following bolus (368 +/- 84 [SD] sec) than by infusion (615 +/- 88 sec), but the maximum block produced, either demonstrated by the reduction in amplitude of T1 from control or the T1:T4 ratio on the integrated electromyogram (Datex IEMG), was similar in each group irrespective of rate of injection, T1 and T4 referring to the first and last twitch in a train of four series.

Adult↗

Sepsis associated with central vein catheters in critically ill patients.

In 440 critically ill patients, the association between different central vein catheter insertion sites, the duration of catheter insertion and catheter-associated sepsis was examined. Of 780 catheter tips studied, 19% were colonized by microorganisms. The incidence of colonization varied with the different insertion sites. The lowest percentage of colonized catheters occurred with catheters inserted via the subclavian vein (15%) and the highest, at the femoral vein insertion site (34%, p less than 0.01). The percentage of catheters colonized increased as the duration of insertion increased, at all insertion sites studied. Catheter colonization was closely related to the development of bacteraemia and was associated with approximately 10% of colonized catheters. Our results suggest that the subclavian site is associated with the lowest infective complication rate. To minimize catheter associated sepsis, catheters at all insertion sites should be used with parsimony and only kept in place for the minimum amount of time that their continuing use is necessary.

Catheterization, Central Venous↗

The clinical significance of elevated CSF and plasma histamine in cerebral aneurysm surgery utilizing cardiopulmonary bypass with total circulatory arrest.

Recently there has been a renewed interest in the neurosurgical treatment of large cerebral aneurysms and AV malformations utilising cardiopulmonary bypass (CPB) and total circulatory arrest (TCA). However, the differing tolerance limits of coagulation and bleeding, pH control and fluid constraint are difficult to reconcile. Although clinical assessment, electro encephalogram (EEG) and intracranial pressure-monitoring assist in identification of cerebral damage, CPB and TCA inflict their own penalties with resultant uncertainty in post-operative neurological evaluation, and producing difficulties in interpretation and management. Additionally, an unanswered question is, to what extent the known cardiac and cerebral effects of circulating histamine might influence the post-circulatory arrest recovery in these patients, and whether this would further compromise the neurological result. We report our experience of 9 such cases who underwent this procedure, and were able to achieve a satisfactory neurological result in 7 patients with differing lesions. During the operation both CSF (from the open cranium) and blood (from the right internal jugular vein) were sampled at intervals for subsequent plasma histamine estimation. Despite markedly elevated histamine levels during CPB and TCA, this was not associated with an unfavourable neurological outcome. These early findings have given us encouragement to the useful role of CPB and TCA in these complex neurosurgical presentations, and raise interesting questions about the clinical importance of histamine-evoked cerebral ischaemia that has been demonstrated in experimental models.

Adult↗

AIDS in ICUs: outcome.

The admission of patients with acquired immune deficiency syndrome (AIDS) to intensive care units in the United Kingdom was surveyed in January 1986. Ninety-three intensive care units completed the questionnaire. Thirty-two patients had been admitted to 12 units up to that time. Twenty-five (78%) of these patients had received artificial ventilation of the lungs. The commonest cause of respiratory failure on admission was Pneumocystis carinii pneumonia; this occurred in 27 patients, seven of whom also had pulmonary cytomegalovirus infection. Four patients had Kaposi's sarcoma and three of these patients also had Pneumocystis carinii pneumonia. The overall mortality was 72%; twenty (80%) of the patients who required artificial ventilation, died. Ten patients survived to leave the intensive care unit, but one patient died of respiratory failure prior to discharge home.

Acquired Immunodeficiency Syndrome↗

Isoflurane in the treatment of asthma.

A 22-month-old child developed severe bronchospasm. Prolonged ventilation of the lungs with isoflurane for 102 hours was used as treatment. The metabolism and fluoride levels obtained are discussed.

Administration, Inhalation↗