Search PubMed⌕ Search

Biomedical subjects

N Soni

Publications and source records attributed to N Soni.

At least 73 records · Page 4Linked to original sources
PubMed1993

Low-dose tumour necrosis factor alpha and melphalan in hyperthermic isolated limb perfusion.

Nine patients with soft tissue tumours of the lower limb not amenable to treatment other than by isolated limb perfusion or amputation underwent hyperthermic isolated limb perfusion at the level of the superficial femoral vessels, using a combination of recombinant tumour necrosis factor (TNF) alpha and melphalan. In seven patients with superficial tumours, necrosis and sloughing was apparent within 48 h of perfusion. All patients experienced a complete tumour response. There were no systemic side-effects associated with the use of TNF-alpha although local side-effects, particularly oedema, were pronounced. Three patients ultimately required amputation because of the large soft tissue defects that resulted from necrosis of the tumour and overlying skin.

Adult↗
PubMed1993

Extra inspiratory work of breathing imposed by cricothyrotomy devices.

Using a lung model for spontaneous ventilation, we have assessed the additional work of inspiration imposed by a variety of cannulae ranging from the 12- and 14-gauge intravascular cannulae to the 8.0-mm i.d. adult tracheostomy tube. Work (W) ranged between 9 and 2262 mJ litre-1 and power (W) between 0.2 and 37.7 mW litre-1 min; the smallest values were obtained with the 8.0-mm i.d. adult tracheostomy tube and the 12- and 14-gauge intravascular cannulae gave the largest values. With any given cannula, W and W were influenced by ventilation (tidal volume and frequency) and ventilatory wave pattern of the analogue lung. The results obtained from the 12- and 14-gauge cannulae represent what is probably an excessive inspiratory workload, whereas the other four devices (Portex MiniTrach, 4.0, 6.0 and 8.0 tracheostomy tubes) may be suitable in the short term for relieving airway obstruction and compatible with spontaneous ventilation.

Cricoid Cartilage↗
PubMed1993

Fresh gas flow requirements during spontaneous ventilation: fresh gas flow to total ventilation ratio or ml kg-1 min-1?

Both the performance of breathing systems and recommendations for the fresh gas flows to be used in patients breathing spontaneously can be expressed in ml kg-1 min-1 or fresh gas: total ventilation ratio (VF:VE). We have examined the relationship between these two descriptions. The data of 106 subjects (awake volunteers and anaesthetized patients) were retrieved from the archives of previous work performed in our department. The two methods of describing the requisite fresh gas produced different results, with correlation coefficients (r) between the methods of r = 0.69 and r = 0.49 for the awake and anaesthetized groups, respectively. The results of the multiple regression models suggest that both baseline total ventilation and body weight may be used to predict the fresh gas flow requirements, but residual analysis did not discriminate which method was a better predictor.

Adolescent↗
PubMed1993

The parallel Lack anaesthetic breathing system.

The parallel Lack system is a new modification of the Mapleson A system comprising separate inspiratory and expiratory tubes. To determine that the function of the system was that anticipated of a Mapleson A, the fresh gas flow requirements to prevent rebreathing during spontaneous ventilation were assessed in three situations: (1) a lung model (2) conscious volunteers and (3) anaesthetised patients. Two sets of criteria to define rebreathing were used; (A) those based on changes in ventilation or end-expired carbon dioxide tension and (B) minimum inspired carbon dioxide tension. Using A, rebreathing occurred at a fresh gas flow to minute ventilation ratio (VF/VE) of 0.75 for the lung model, and 0.73 for conscious volunteers. These results were comparable to those obtained for a Magill attachment. They were also close to the point at which mechanical dead space began to increase in the lung model. Criteria B gave much lower values for the onset of rebreathing. Rebreathing was present by criteria A in five of the six anaesthetised patients at a fresh gas flow of 60 ml.kg-1.min-1 (VF/VF of 0.78). The results confirm that the parallel Lack behaves as a Mapleson A system. The resistance to breathing posed by the parallel Lack was also comparable to the Magill system.

Adult↗
PubMed1993

The additional work of breathing imposed by Mapleson A systems.

The additional work attributable to breathing through five Mapleson A anaesthetic breathing systems (Magill, Lack, Parallel Lack, Humphrey ADE and Enclosed Magill) was studied using a lung model. With all five systems, the additional work was found to be a function of fresh gas flow, respiratory flow as well as system geometry. Within the range of fresh gas flow and respiratory flow studied, the additional work ranged between 80 mJ.l-1 and 182 mJ.l-1. Expiratory work was always greater than the inspiratory workload. Increasing fresh gas inflow into the system increases expiratory work, both resistive and elastic components. The Magill system posed the least work expenditure. The values for the additional work obtained with the lung model were of the same order of magnitude when measurements were taken in volunteers.

Adult↗
PubMed1993

C-reactive protein and its cytokine mediators in intensive-care patients.

C-reactive protein (CRP) is an acute-phase protein produced by the liver during bacterial infections and inflammation. The cytokines interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF) are widely reported to induce synthesis of CRP by hepatocytes both in vitro and in vivo. We investigated the relation between CRP and its cytokine mediators in 64 critically ill patients during their treatment in the intensive-care unit. Plasma CRP and IL-6 concentrations were significantly lower in patients without any evidence of infection than in those with clinical infection; plasma IL-1 beta concentrations showed no significant difference between any of the groups, but plasma TNF concentrations were lower in patients with evidence of infection. Significant correlation was seen between plasma concentrations of CRP and IL-6 when the latter was measured by bioassay; however, IL-6 showed, at best, only a 50% predictive value for a change in CRP concentration.

Bacterial Infections↗
PubMed1992

A high flow semi-open system for preoxygenation: an evaluation.

We have compared an alternative breathing system for preoxygenation comprising a Hudson face mask with high oxygen inflow (48 litre min-1) and a Mapleson A breathing system (100 ml kg-1 min-1). The study consisted of two parts: the first involved adult volunteers (10 male, seven female) and the second part used a lung model for spontaneous ventilation with a sinusoidal ventilatory wave pattern. In the volunteers, preoxygenation was achieved at mean times of 138 (SD 31.3) s and 164 (SD 36.7) s with the high flow semi-open and Mapleson A systems, respectively. In the lung model, at peak inspiratory flow rates of 30 and 40 litre min-1, the preoxygenation times were 139 and 120 s, respectively, with the semi-open system and 167 and 156 s with the Mapleson A system. The high flow semi-open system may be an alternative for current techniques, provided peak inspiratory flows are not excessive.

Adult↗
PubMed1992

Nitrous oxide administration using commonly available oxygen therapy devices.

Administration of nitrous oxide is useful for providing sedation and analgesia. The therapeutic range for nitrous oxide is 20-30%. Several oxygen treatment devices have been used for administering nitrous oxide, but little is known about the concentrations of nitrous oxide and oxygen delivered to the trachea. We have studied this, using an analogue lung model, with several oxygen therapy devices. With a 1:1 nitrous oxide-oxygen mixture in the primary flow for all systems, end-expired nitrous oxide concentrations varied between 6.5% and 34.3%. Therapeutic concentrations were produced using the Hudson (nominal oxygen concentration 60%) fixed-performance mask, the variable performance Hudson mask at 4 litre min-1, the MC masks at 4 and 6 litre min-1 and the nasal prongs at 6 and 8 litre min-1. Simultaneous end-expired oxygen concentrations for all devices tested were within a safe range.

Analgesia↗
PubMed1992

Colloid solutions in the critically ill. A randomised comparison of albumin and polygeline. 1. Outcome and duration of stay in the intensive care unit.

All patients admitted to an Intensive Care Unit were randomised to receive all volume replacement fluid as either human albumin solution or a synthetic colloid. A total of 475 patients were admitted during the study period. Patients' age, sex, APACHE score and calculated risk of death were assessed on admission. Outcome was assessed as length of Intensive Care stay and mortality. There was no difference between the groups. Subgroups of patients with APACHE score greater than 10, calculated risk of death greater than 50% and length of stay greater than 5 days were also evaluated but not significant differences were found between treatment groups. The use of albumin rather than 3.5% polygeline for volume replacement in the Intensive Care Unit has no influence on outcome.

Adolescent↗
PubMed1992

Colloid solutions in the critically ill. A randomised comparison of albumin and polygeline 2. Serum albumin concentration and incidences of pulmonary oedema and acute renal failure.

All patients admitted to an Intensive Care Unit were assigned randomly to one of two groups, A and B. Group A received colloid volume replacement as 4.5% albumin whilst group B received a synthetic colloid, polygeline. This study describes the changes in serum albumin concentration in survivors and nonsurvivors in the two groups during their stay in the Intensive Care Unit. The incidences of renal failure and pulmonary oedema were also assessed. Serum albumin concentration decreased in all nonsurvivors. In survivors the serum albumin concentration decreased to a greater extent in the synthetic colloid group than in the albumin group. Despite the differences in serum albumin concentration there were no significant differences between the groups in the incidences of pulmonary oedema or renal failure.

Acute Kidney Injury↗
PubMed1992

An evaluation of oxygen delivery using nasal prongs.

Oxygen delivery using nasal prongs was assessed using a lung model for spontaneous ventilation. The analogue lung was attached to a manikin, which provided a model of the 'face and pharynx' to which the nasal prongs were applied. Oxygen concentrations were measured in the model trachea at varying fresh gas inflow and peak inspiratory flows. The study demonstrated enormous variability in the both the peak-inspired (26.3-90.0%) and end-expired concentrations (25.2-78.6%) of oxygen delivered to the trachea. There was a regular relationship between the ratio of peak inspiratory flows, expressed over fresh gas inflow and the end-expired oxygen concentrations which could allow estimation of inspired oxygen concentration.

Evaluation Studies as Topic↗
PubMed1992

Pre-oxygenation: the Hudson mask as an alternative technique.

The use of a simple oxygen facemask (Hudson) with high oxygen inflow (48 l.min-1) was investigated as a technique for pre-oxygenation, comparing it with the Magill system (oxygen flow: 100 ml.kg-1.min-1). One hundred and thirty-eight patients scheduled for elective gynaecological and orthopaedic surgery were studied: group 1, Hudson mask and group 2, Magill system (ASA 1-2, n = 107); group 3, Hudson mask and group 4, Magill system (ASA 3, n = 30). Pre-oxygenation was assessed by measuring the times to 97%, 95% and 93% arterial desaturation (finger pulse oximetry) following 3 min of pre-oxygenation. The times taken to achieve these end-points in all the study groups suggest that the Hudson mask offers an alternative technique for pre-oxygenation.

Adult↗
PubMed1992

Nitrous oxide-oxygen analgesia: the performance of the MC mask delivery system.

Nitrous oxide administration via an oxygen facemask such as the Mary Catterall (MC) is an accepted technique for supplementing regional anaesthesia. This study assessed the range of nitrous oxide and oxygen concentrations delivered to the trachea using a mechanical lung model. The inspired concentrations of these two gases were determined by the total fresh gas inflow rates, their concentrations in the fresh gas mixture and the peak inspiratory flow rate of the analogue lung. A 1:1 nitrous oxide-oxygen mixture in the fresh gas with an inflow rate of 4-6 l/min is recommended to ensure adequate oxygen delivery into the trachea as well as achieving the therapeutic concentrations of nitrous oxide (20-30%).

Analgesia↗