Biomedical subjects
Publications and source records attributed to N Soni.
Failed intubation associated with difficulty with ventilation is rare. Cricothyrotomy may provide a means of oxygenating the patient, but in practice it may be difficult to perform and does not establish a definitive airway. We report two patients in whom percutaneous tracheostomy was used as an emergency procedure. In both cases placement was extremely rapid and salvaged the situation, leaving a definitive airway.
The fibrin assay system (FAS) has been designed to address the problem of in-situ diagnosis of central venous catheter (CVC) colonization. The FAS was evaluated in 12 critically ill patients with daily brushings, comparing results with culture of the catheter tip and blood. Data analysis of the FAS showed a sensitivity of 0 with a specificity of 1.0. The study was repeated in a further 12 high-risk patients with a single terminal brushing on catheter removal. This gave a sensitivity of 0.14 and a specificity of 0.8. Differences in sensitivity may be due to daily disruption of the endoluminal fibrin clot. Our results do not support the routine use of the FAS to detect CVC colonization in the intensive care unit.
This laboratory study was designed to compare the speed of placement of a percutaneous tracheostomy using two common methods and to evaluate any damage caused to the trachea. The same operator who was experienced with both techniques placed 10 percutaneous tracheostomies into a pig tracheal model, five using the Griggs tracheostomy forceps technique and five using the Ciaglia sequential dilatation technique. Placement of the tracheostomy was significantly faster using the Griggs technique (mean 89 s, range 69-105 s) than using the Ciaglia sequential dilator technique (mean 217 s, range 180-267 s). Damage to the posterior wall was noted in four of the tracheas. We concluded that the Griggs technique is rapid and in trained hands may be suitable for emergency airway access. In addition, the pig trachea model is easy to set up and provides a very useful training tool.
Sevoflurane, desflurane and isoflurane were compared using a circle system in 97 patients undergoing short surgical procedures. Using initial high flows, the time intervals to equilibration between inspired and end-expired agent concentrations were measured; equilibration was defined as FE/FI = 0.8. The mean (SD) times obtained for sevoflurane, desflurane and isoflurane were 8.2 (2.1) min, 3.8 (0.7) min and 19.7 (6.5) min, respectively. These times were significantly different from each other (p < 0.0001). After equilibration total flow were reduced to 500 ml.min-1; at these flows the initial decline in end-expired agent concentration was minimal with desflurane, intermediate with sevoflurane and greatest with isoflurane. Both desflurane and sevoflurane are appropriate for efficient use of the circle system during short anaesthetics.
A case of severe methaemoglobinaemia caused by the abuse of volatile nitrites is reported. The agents are commonly abused, but this complication is rare. The clinical presentation can make diagnosis difficult; however, the subsequent treatment needs to be rapid to avoid serious morbidity or mortality. This report presents the clinical picture and the background information leading to the detection and treatment of this unusual problem.
We report a patient presenting with pneumonia in whom temporary splenic dysfunction was diagnosed by counting pitted red blood cells. This under-recognised condition caused a transient immunosuppression which may have had serious implications for our patient's recovery.
PURPOSE: Etoposide has schedule-dependent cytotoxic activity, and clinical resistance may be overcome with prolonged low-dose therapy. Oral bioavailability is variable, and protracted intravenous administration is limited by water insolubility, which requires large infusion volumes. Etoposide phosphate (EP) is a water-soluble prodrug that is rapidly converted in vivo to etoposide, and may be administered in concentrated solution. A phase I study was conducted to determine the toxicity, pharmacokinetics, and pharmacodynamics of EP administered as a protracted venous infusion in the ambulatory setting. METHODS: Twenty-three patients with advanced cancer were treated with a continuous infusion of EP using ambulatory pumps for 6 weeks followed by a 2-week rest. Cohorts were treated with EP at 10, 20, 25, and 30 mg/m2/d. Steady-state plasma etoposide levels (Css) and stability of EP in infusion pumps were measured using high performance liquid chromatography (HPLC). RESULTS: Myelosuppression, mucositis, and fatigue were dose-limiting. The maximum-tolerated dose (MTD) of EP was 20 mg/m2/d. The mean Css (+/- SD) of etoposide were 0.67 +/- 0.25, 1.14 +/- 0.24, 1.38 +/- 0.64, and 2.19 +/- 0.52 microg/mL at daily EP doses of 10, 20, 25, and 30 mg/m2, respectively. Neutropenia correlated with Css (r = 0.65, P = .008). EP was stable in infusion pumps for at least 7 days. Partial responses were observed in patients with hepatoma and non-small-cell lung cancer (one each). CONCLUSION: EP may be conveniently and safely administered as a low-volume protracted venous infusion in the ambulatory setting. Cytotoxic plasma concentrations of etoposide are obtained at the MTD. The pharmacodynamic relationships observed suggest the possibility of pharmacologically based dosing of EP.
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Interleukin-2 (IL-2) is a potent immunomodulator that has been associated with the clinical development of autoimmune disorders. However, diabetes mellitus has not been reported in patients treated with single-agent IL-2. We conducted a clinical trial of a protracted daily schedule of subcutaneously administered low-dose IL-2. A patient with advanced colorectal cancer, treated with 1.5 x 10(6) international units of IL-2 daily, developed insulin-requiring diabetes during therapy. Hyperglycemia improved during treatment interruption and recurred with reinstitution of IL-2. The diabetes in this patient developed in the context of T cell and natural killer cell expansion, and the presence of islet cell autoantibodies was documented. We postulate that, in this patient, IL-2 reversed the anergy of autoreactive T cells that had escaped clonal deletion. It is possible that prolonged daily exposure to immunomodulatory doses of IL-2 will result in the development of autoimmune phenomena not observed with other schedules of administration.
Juvenile hyaline fibromatosis is a rare autosomal recessive disease characterized by large cutaneous nodules, especially around the head and neck and often involving the lips. The effects become increasingly severe with age and also include joint contractures, gingival hypertrophy and osteolytic lesions. We describe the anaesthetic management of two sisters with this disease. Safe maintenance of a patent airway is the principal anaesthetic challenge.
Patients undergoing short surgical procedures but requiring ventilation of the lungs were allocated randomly to receive either desflurane or isoflurane by circle absorption system, initially at a high fresh gas flow. The inspired and expired concentrations of the volatile agent were measured and the fresh gas flows reduced to low flow (500 ml min-1 total when FE/FI = 0.8), as measured on a multigas analyser. In patients receiving desflurane (n = 32), the median time at which flows were reduced was 5 min (interquartile range (IQR) 1 min) while with isoflurane (n = 32), the median time was 19 (IQR 12) min. After the reduction in flow, expired concentrations of volatile agent decreased in both groups. In the isoflurane group the concentration continued to decrease during anaesthesia. In the desflurane group the initial decrease was followed by a slow recovery. We conclude that the circle system can be used efficiently for short anaesthetics using desflurane.
There is no doubt that a group of patients at increased risk of peri-operative cardiac morbidity exists and must be managed with the emphasis on the prevention of myocardial ischaemia. It is also clear that a potentially far larger group are at risk of failing to meet the increased cardiovascular and metabolic demands of surgery and therefore suffering the consequences of a relative hypoperfusion injury. Pre-operative assessment must address both groups and management regimens sought to provide optimal outcome for both. At present there is no consistent strategy for their identification, assessment or management of the high risk surgical population despite the fact that they probably consume a disproportionate share of hospital resources. The first and most important step is the recognition that this high risk group exists. Only then can this population be given similar consideration to those currently thought to be at risk of ischaemia.
OBJECTIVE: To investigate the value of decreasing plasma C-reactive protein (CRP) concentrations as an indicator or resolution of microbiologically-proven sepsis. DESIGN: Retrospective analysis of CRP concentrations measured during episodes of microbiologically-proven sepsis. A receiver-operating characteristic (ROC) curve was used to assess the usefulness of CRP as a test for resolution of sepsis. SETTING: The intensive care unit (ICU) of a teaching hospital. PATIENTS AND PARTICIPANTS: 32 episodes of microbiologically-proven sepsis occurring in 18 patients were followed from diagnosis until resolution. MEASUREMENTS AND RESULTS: Daily routine observations and blood testing were performed prospectively. The daily presence or absence of systemic inflammatory response syndrome (SIRS) was prospectively determined according to standard definitions. Concentrations of CRP were analysed retrospectively once the patients had left the ICU. A decrease in CRP by 25% or more from the previous day's level was a good indicator of resolution of sepsis, with a sensitivity of 97%, specificity of 95% and predictive value of 97%. In 13 cases (46%), a decrease in CRP preceded clinical resolution of sepsis; this was more likely to occur in patients with less severe sepsis than in those with severe sepsis or septic shock. CONCLUSION: Daily measurement of CRP is useful for monitoring the course of microbiologically-proven sepsis in ICU patients, and may be used to indicate successful treatment.
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The cytokines interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF alpha) have been implicated in the pathophysiology of sepsis and the systemic inflammatory response syndrome (SIRS). The anti-endotoxin antibody, HA-1A (Centoxin), introduced as a treatment for sepsis, was withdrawn because of possible toxicity in some patients. There has been little investigation of the effects of HA-1A on cytokine production. Sixty-one whole blood samples from 15 intensive care unit (ICU) patients with SIRS were incubated for 24 h with HA-1A and concentrations of cytokines determined. Concentrations of IL-6 exceeded those in samples incubated without HA-1A by more than 25% in five patients, of whom four died. One death occurred among 10 patients for whom IL-6 concentrations did not increase (P = 0.03). Incubation with HA-1A did not increase concentrations of IL-1 beta or TNF alpha. HA-1A did not affect cytokine production in whole blood from healthy subjects. HA-1A may induce IL-6 production in whole blood from some ICU patients and this response is associated with increased mortality. Immune therapies for treatment of sepsis and SIRS require careful evaluation of their ability to affect cytokine production, before they are introduced for general use.