Estimated costs before, during and after the introduction of the emergency laparotomy pathway quality improvement care (ELPQuIC) bundle.

Implementation of a quality improvement bundle for peri-operative management of emergency laparotomy (ELPQuIC) improved mortality in a previous study. We used data from one site that participated in that study to examine whether it was associated with the cost of care. We collected data from 396 patients: 144 before, 144 during and 108 after implementation of the bundle. We estimated costs incurred using previously published methodology based on the time the patient spent in hospital, in the operating theatre and in critical care. Duration of stay in hospital and critical care did not differ between time periods, p = 0.14 and p = 0.28, respectively. The costs per patient and per survivor did not differ between the time periods, p = 0.87 and p = 0.17, respectively. Costs were similar for patients aged < 80 years vs. ≥ 80 years. Implementation of a quality improvement bundle for emergency laparotomy has the capacity to save lives without increasing hospital costs.

Postoperative morbidity survey, mortality and length of stay following emergency laparotomy.

Thirty-day mortality following emergency laparotomy is high, and greater amongst elderly patients. Studies systematically describing peri-operative complications are sparse, and heterogeneous. We used the postoperative morbidity survey to describe the type and frequency of complications, and their relationship with outcomes for 144 patients: 114 < 80 years old, and 30 ≥ 80 years old. Cumulative postoperative morbidity survey scores and patterns of morbidity were similar (p = 0.454); however, 28-day mortality was higher in the elderly (10/30 (33.3%) vs. 11/114 (9.6%), p = 0.008), and hospital stay was longer (median (IQR [range]) 17 (13-35 [6-62]) days vs. 11 (7-21 [2-159]) days, p = 0.006). Regression analysis indicated that cardiovascular, haematological, renal and wound complications were associated with longer hospital stay, and that cardiovascular complications predicted mortality. The postoperative morbidity survey system enabled structured mapping of the number and type of complications, and their relationship with outcome, following emergency laparotomy. These results indicate that rather than a greater propensity to complications following surgery, it was the failure to tolerate these that increased mortality in the elderly.

Rescuing the obese or burned airway: are conventional training manikins adequate? A simulation study.

BACKGROUND: Percutaneous tracheal access is required in more than 40% of major airway emergencies, and rates of failure are high among anaesthetists. Supraglottic airway management is more likely to fail in patients with obesity or neck pathology. Commercially available manikins may aid training. In this study, we modified a standard 'front of neck' manikin and evaluated anaesthetists' performance of percutaneous tracheal access. METHODS: Two cricothyroidotomy training manikins were modified using sections of belly pork to simulate a morbidly obese patient and an obese patient with neck burns. An unmodified manikin was used to simulate a slim patient. Twenty consultant anaesthetists were asked to manage a 'can't intubate, can't ventilate' scenario involving each of the three manikins. Outcome measures were success using their chosen technique and time to first effective breath. RESULTS: Success rates using first-choice equipment were: 'slim' manikin 100%, 'morbidly obese' manikin 60%, and 'burned obese' manikin 77%. All attempts on the 'slim' manikin succeeded within 240 s, the majority within 120 s. In attempts on the 'morbidly obese' manikin, 60% succeeded within 240 s and 20% required more than 720 s. All attempts on the 'burned obese' manikin succeeded within 180 s. CONCLUSIONS: Significantly greater technical difficulty was experienced with our 'morbidly obese' manikin compared with the unmodified manikin. Failure rates and times to completion were considerably more consistent with real-life reports. Modifying a standard manikin to simulate an obese patient is likely to better prepare anaesthetists for this challenging situation. Development of a commercial manikin with such properties would be of value.

The use of a prospective audit proforma to improve door-to-mask times for acute exacerbations chronic obstructive pulmonary disease (COPD) requiring non-invasive ventilation (NIV).

Non-invasive ventilation (NIV) is an evidence based management of acidotic, hypercapnic exacerbations of COPD. Previous national and international audits of clinical practice have shown variation against guideline standards with significant delays in initiating NIV. We aimed to map the clinical pathway to better understand delays and reduce the door-to-NIV time to less than 3 hours for all patients with acidotic, hypercapnic exacerbations of COPD requiring this intervention, by mandating the use of a guideline based educational management proforma.The proforma was introduced at 7 acute hospitals in North London and Essex and initiated at admission of the patient. It was used to record the clinical pathway and patient outcomes until the point of discharge or death. Data for 138 patients were collected. 48% of patients commenced NIV within 3 hours with no reduction in door-to-mask time during the study period. Delays in starting NIV were due to: time taken for review by the medical team (101 minutes) and time taken for NIV to be started once a decision had been made (49 minutes). There were significant differences in door-to-NIV decision and mask times between differing respiratory on-call systems, p < 0.05). The introduction of the proforma had no effect on door-to-mask times over the study period. Main reasons for delay were related to timely access to medical staff and to NIV equipment; however, a marked variation in practice within these hospitals was been noted, with a 9-5 respiratory on-call system associated with shorter NIV initiation times.

Role of mitochondrial variation in maternally inherited diabetes and deafness syndrome.

Maternally inherited diabetes and deafness syndrome is caused by the mitochondrial deoxyribonucleic acid mutation 3243 A>G (where A = adenine and G = guanine). The degree of heteroplasmy of the mitochondrial deoxyribonucleic acid may correlate with the rate of progression of the hearing loss. This has important implications for counselling patients with this pathology. Cochlear implantation is a successful method of rehabilitation for patients with hearing loss as part of this syndrome.

Effect of particle properties on the flowability of ibuprofen powders.

Powder flowability is one of the key parameters in the pharmaceutical tabletting process. The flowability is affected by both the particles' properties and the tabletting equipment characteristics. Although it is generally accepted that powder flowability increases with an increase in particle size, quantitative studies and comprehensive theoretical insights into the particle property effects are still lacking. In this paper, ibuprofen, a non-steroidal drug widely used as an anti-inflammatory analgesic was chosen as a model material to assess the effect of particle properties on its flowability. Ibuprofen typically has a needle shaped morphology. The flowability of ibuprofen size fractions was studied in detail using two flow measurement methods. The separated fractions were also compared to magnesium stearate lubricated ibuprofen and its size fractions. The experimental results showed that powder flowability is significantly affected by both the particle size and size distribution. The finest size fraction that is separated from the bulk ibuprofen powder flows better than the bulk powder. For powders with narrow size distributions, the flowability increases significantly with the increase in particle size. In addition, admixing magnesium stearate to ibuprofen not only increases the flow function of the powder, but also reduces the internal friction angle. A theoretical analysis based on the limiting tensile strength of the powder bed was carried out and the flow conditions for particles of different size and shape were developed.

Hydrocolloid gel particles: formation, characterization, and application.

Hydrocolloid gel particles of micron and sub-micron size are particularly attractive for use in many applications in the food, agricultural, pharmaceutical, and chemical industries, due to their biocompatibility, perception as "natural" materials, and soft-solid texture. Industrial applications for such particles include uses as texturizers in confectionery and cosmetic products, slow-release encapsulation agents for flavors, nutrients, and pharmaceutical products, and thickeners in soups and sauces. Properties such as particle size, hardness, shape, texture, and molecular release rates can be important for individual applications. In addition, product formats will determine specific needs for physical form (e.g. dry or wet) and compatibility with other components. The diverse range of potential applications for hydrocolloid gel particles provide a driver for understanding-led tailoring of raw material and process conditions. This review introduces some of the materials that are used to form hydrocolloid gel particles and the corresponding gel formation mechanisms. One issue of importance in the production of hydrocolloid gel particles is the control of particle properties, such as release profiles, strength, and detectability within products. An alternative technique to traditional methods of hydrocolloid gel particle production is evaluated and a model for control of particle size, and subsequently other particle properties, is proposed. Key properties of hydrocolloid gel particles are identified and characterization methods for evaluating these properties are described.

Residence time distributions of gas flowing through rotating drum bioreactors.

Residence time distribution studies of gas through a rotating drum bioreactor for solid-state fermentation were performed using carbon monoxide as a tracer gas. The exit concentration as a function of time differed considerably from profiles expected for plug flow, plug flow with axial dispersion, and continuous stirred tank reactor (CSTR) models. The data were then fitted by least-squares analysis to mathematical models describing a central plug flow region surrounded by either one dead region (a three-parameter model) or two dead regions (a five-parameter model). Model parameters were the dispersion coefficient in the central plug flow region, the volumes of the dead regions, and the exchange rates between the different regions. The superficial velocity of the gas through the reactor has a large effect on parameter values. Increased superficial velocity tends to decrease dead region volumes, interregion transfer rates, and axial dispersion. The significant deviation from CSTR, plug flow, and plug flow with axial dispersion of the residence time distribution of gas within small-scale reactors can lead to underestimation of the calculation of mass and heat transfer coefficients and hence has implications for reactor design and scale-up.

Approach to designing rotating drum bioreactors for solid-state fermentation on the basis of dimensionless design factors.

The development of large-scale solid-state fermentation (SSF) processes is hampered by the lack of simple tools for the design of SSF bioreactors. The use of semifundamental mathematical models to design and operate SSF bioreactors can be complex. In this work, dimensionless design factors are used to predict the effects of scale and of operational variables on the performance of rotating drum bioreactors. The dimensionless design factor (DDF) is a ratio of the rate of heat generation to the rate of heat removal at the time of peak heat production. It can be used to predict maximum temperatures reached within the substrate bed for given operational variables. Alternatively, given the maximum temperature that can be tolerated during the fermentation, it can be used to explore the combinations of operating variables that prevent that temperature from being exceeded. Comparison of the predictions of the DDF approach with literature data for operation of rotating drums suggests that the DDF is a useful tool. The DDF approach was used to explore the consequences of three scale-up strategies on the required air flow rates and maximum temperatures achieved in the substrate bed as the bioreactor size was increased on the basis of geometric similarity. The first of these strategies was to maintain the superficial flow rate of the process air through the drum constant. The second was to maintain the ratio of volumes of air per volume of bioreactor constant. The third strategy was to adjust the air flow rate with increase in scale in such a manner as to maintain constant the maximum temperature attained in the substrate bed during the fermentation.

Effect of L-arginine on renal blood flow in normal subjects and patients with hypoxic chronic obstructive pulmonary disease.

BACKGROUND: L-arginine is the precursor of endothelium derived nitric oxide (NO) and increasing the available substrate may increase the production of NO. This has been shown by local infusion in peripheral vascular beds but there are few studies of the effects during systemic infusion. Renal vasoconstriction is known to be important in the pathogenesis of cor pulmonale in patients with hypoxic chronic obstructive pulmonary disease (COPD). The effects of a systemic infusion of L-arginine on renal and aortic haemodynamics were therefore investigated in normal subjects and in patients with hypoxic COPD. METHODS: Ten normal volunteers were recruited from the research staff of King's College Hospital Six patients with COPD and hypoxia (arterial oxygen tension (PaO2) < 8.5 kPa) were recruited from the thoracic medicine outpatient clinic at King's College Hospital and five age and sex matched normal subjects were recruited from a group of normal subjects recruited from the database of the Department of Health Care for the Elderly as volunteers for medical research. There was no history of renal, cardiac, or hepatic disease. Baseline values of time averaged mean of the maximum instantaneous velocity (Tamx) and maximum velocity (Vmax) of blood flow in intrarenal arteries were obtained using colour flow Doppler ultrasound. Using the same technique, Vmax was obtained from the abdominal aorta just distal to the xiphisternum before and after infusion of L-arginine via a large peripheral vein (20 g in 100 ml sterile water over 30 minutes). RESULTS: In normal subjects L-arginine increased blood velocity in the intrarenal vessels from a mean of 0.22 m/s to 0.26 m/s, an increase of 19.8%. There was no effect on arterial blood pressure, heart rate, or aortic blood velocity. L-arginine had no effect on intrarenal or aortic blood velocity in patients with hypoxic COPD. In age matched controls L-arginine increased blood velocity in the intrarenal vessels from a mean of 0.20 m/s to 0.26 m/s, an increase of 36.8%. There was no effect on arterial blood pressure, heart rate, or aortic blood velocity. CONCLUSIONS: L-arginine, at the doses administered, increased renal blood flow, as assessed by renal arterial velocity. This effect was not seen in patients with hypoxic COPD but was present in age matched controls. This suggests that the abnormal renal vascular control seen in hypoxic patients with COPD may reflect a disturbance of the L-arginine/nitric oxide pathway.

The effects of oxygen and dopamine on renal and aortic blood flow in chronic obstructive pulmonary disease with hypoxemia and hypercapnia.

Renal blood flow is reduced in patients with chronic respiratory failure caused by chronic obstructive pulmonary disease (COPD), and changes in renal hemodynamics are likely to be important in the pathogenesis of the edematous state of cor pulmonale. We therefore examined the hypothesis that this renal vasoconstriction is reversible by comparing the effects of oxygen therapy and the renal vasodilator dopamine on renal hemodynamics in both hypoxemic patients with COPD and those who were also hypercapnic. We assessed renal hemodynamics noninvasively with color-flow Doppler ultrasound. In order to validate the technique we recorded renal hemodynamics in a group of healthy volunteers before and during a dopamine infusion, and in a subgroup we simultaneously measured effective renal plasma flow (ERPF) with para-aminohippurate clearance. In the healthy volunteers there was a 22.5% rise in time-adjusted mean arterial velocity (Tamx) measured by Doppler compared with a 22% rise in ERPF with dopamine. This rise was significant (p < 0.05). In hypoxemic, normocapnic subjects Tamx rose by 25% with oxygen (p < 0.005), 20% with dopamine (p < 0.005), and 24% with both therapies. There was no significant change in aortic flow whether the subjects received air, oxygen, or dopamine (p = 0.77). In the hypercapnic patients there was no significant change in aortic or renal velocities while receiving oxygen or dopamine (p = 0.85 and 0.86). We conclude that color-flow Doppler velocity measurements can accurately detect changes in renal blood flow. Oxygen and dopamine are equipotent renal vasodilators in hypoxic COPD, but the effect is not additive.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of beta 2-agonists and caffeine on respiratory and limb muscle performance.

The possibility that respiratory muscle function may be improved by drug therapy is of clinical importance, but remains controversial. A series of studies concerning the effects of maximally tolerated dosages of terbutaline, tulobuterol (a new beta 2-agonist) and caffeine on respiratory muscle strength and limb muscle strength and endurance were undertaken in normal subjects. Drugs were administered orally, 2 h before study. Caffeine produced a small but statistically significant increase in the stimulated contraction force at 20 Hz, and a small beneficial effect on recovery from a fatiguing protocol; maximum voluntary contraction force of the quadriceps was increased by 3.8%. Terbutaline and tulobuterol had no beneficial effects on either respiratory or limb muscle function. We conclude that conventional dosages of these bronchodilator drugs do not greatly affect skeletal muscle performance.

Response of the microcirculation in rat cremaster muscle to peripheral and central sympathetic stimulation.

Microvascular diameter and flow responses to peripheral and central sympathetic stimulation were measured in different segments of the arteriolar network in rat cremaster muscle. For peripheral stimulation, a bipolar electrode was placed on the internodal segment of the lumbar sympathetic chain between ganglia L1 and L2. For central stimulation, a bipolar electrode was stereotaxically implanted in the posterior hypothalamus. Inside vessel diameter, red blood cell velocity, and volumetric flow rate were recorded in response to electrical stimulations of varying magnitude in four series-coupled segments of the arteriolar network: 1A, 2A, 3A, and 4A. Systemic arterial pressure was also monitored. The vasoconstriction and flow reduction produced by stimulation of the lumbar chain was graded with the frequency of stimulation over the range of 0.5-16.0 Hz in all arteriolar segments. Examination of the relation between stimulation frequency and vasoconstrictor response measured as percent of control diameter indicated a sequence of responsiveness to peripheral stimulation where 4A = 3A greater than 2A = 1A. No changes in diameter were recorded in the venous microcirculation at any level of stimulation. Stimulation of the posterior hypothalamus with currents of 38-300 microA for 60 seconds produced graded vasoconstriction in only 3A and 4A vessels. Fluorescence histochemistry for biogenic amines was used to examine the distribution of innervation to the microvasculature. All segments of the arteriolar network from 1A to 4A possessed an adrenergic innervation; no vessels of the venous network were found to be innervated. The results indicate that the pattern of response of the arteriolar network in rat cremaster muscle to peripheral and central sympathetic stimulation is segmentally differentiated and consistent with the distribution of the vasomotor innervation.