Continuous monitoring of right atrial oxygen tension in patients with myocardial infarction.

Right atrial oxygen tension (RAPvO2) was measured continuously in 26 patients admitted to a coronary care unit with acute myocardial infarction. A catheter incorporating a Clark type oxygen sensor at its tip was inserted percutaneously into the right atrium. Insertion was simple, safe and comparable to the introduction of a standard central venous pressure line. RAPvO2 correlated well with the patients' clinical condition and reflected both cardiac and pulmonary function. When breathing air 11 of the patients had sustained RAPvO2 levels of less than 34 mmHg (4.53 kPa). In this group there were eight deaths. Fifteen patients had an RAPvO2 greater than 34 mmHg (4.53 kPa) except for transient falls related to movement and in this group there were no deaths (p less than 0.002). The correction of arterial hypoxaemia by oxygen therapy raised RAPvO2 and lowered the heart rate. In some patients Dopamine and transvenous pacing raised RAPvO2 and could be adjusted with reference to the continuous recording. Movement often caused marked falls in RAPvO2 especially in the seriously ill. Evidence relating RAPvO2 to mixed venous oxygen and tissue oxygen is reviewed.

Fluid requirements of patients with burns and inhalation injuries in an intensive care unit.

We have studied 9 patients with burns (20%-75%) who had inhalation injuries and compared their actual fluid requirements with their requirements calculated from the Muir and Barclay formula. All patients were resuscitated with plasma protein fraction at a rate sufficient to keep their physiological variables within the following range: heart rate less than 120/min, central venous pressure 8-12 cm H2O, urine output greater than 30-50 ml/h, systolic blood pressure greater than 90 mm Hg and diastolic blood pressure greater than 60 mm Hg. The amount of plasma protein fraction needed was 4.38 +/- 1.26 ml/kg/% burn in the first 24 h and 2.15 +/- 0.97 ml/kg/% burn in the second 24 h. This is an increase of 75% and 110% respectively above values predicted from the formula. We suggest that the observed difference is due to a combination of the presence of an inhalation injury which increases fluid requirements by approximately 30% in the first 24 h and the use of plasma protein fraction rather than the dried plasma used in the original Muir and Barclay formula.

The cost of intensive care: a comparison on one unit between 1988 and 1991.

OBJECTIVE: To assess the changes in cost of intensive care in one unit after a 3 year period and to evaluate the relative costs of an integrated high dependency unit. DESIGN: Combined retrospective and prospective audit of all expenditure incurred in an intensive care/high dependency unit over two periods: April 1988-February 1989 and January-July 1991. SETTING: Combined 13-bedded intensive care/high dependency unit of a central London teaching hospital. RESULTS: The overall cost rose by 50%. Hidden costs such as infrastructure maintenance, capital assets, pathology and radiology services accounted for nearly a quarter of total expenditure. Pharmacy and supplies each accounted for some 10% of total expenditure whereas staff costs exceeded 50%. The cost of the intensive care section rose by 14% of 1149 pounds per patient day as increased bed occupancy offset increases in nurse: patient ratios and expenditure on consumables. However, the cost of the high dependency unit section rose by 87% to 437.83 pounds. This was due to a lower bed occupancy (through increased patient turnover), improved staffing ratios, and increased utilisation of equipment and supplies. CONCLUSIONS: Intensive care is an increasingly expensive speciality, the costs for which are rising over and above the rate of general inflation. Staff costs are by far the largest single item of expenditure. Large reductions in spending on drugs and consumables are unlikely to provide considerable savings on the total budget. Hidden costs account for a high proportion of the budget and should be taken into account when evaluating cost. The significantly lower cost of high dependency care should encourage studies into its cost-effectiveness.

Endoreduplication and telomeric association in a choroid plexus carcinoma.

Cytogenetic studies showed a hyperhaploid stemline, (32,XY,+1,+7,+9,+12,+13,+14,+19,+20) in a patient with choroid plexus carcinoma. Endoreduplication and doubling of the stemline to 200-400 chromosomes per cell and variation in numerical changes were also noted. Telomeric association was present in most cells. The 12p and 20q were by far the most frequently involved chromosome arms. Telomeric association is believed to have triggered further structural changes in this case since the 12p and 20q were always involved in the few structural abnormalities identified. A review of the literature suggests that hyperhaploidy may characterize choroid plexus carcinoma and hyperdiploidy choroid plexus papilloma.

Cytogenetic evidence that a tumor suppressor gene in the long arm of chromosome 1 contributes to glioma growth.

In a patient with a rare subtype of glioma, pleomorphic xanthoastrocytoma, cytogenetic studies revealed that both homologues of chromosome 1 were involved in translocations at the same band 1q42 but with different partner chromosomes. In addition, 5 glioblastomas out of 25 gliomas karyotyped in our laboratory had lost at least one copy of band 1q42 through deletions, unbalanced rearrangements, or chromosome losses. Twenty-one gliomas that had lost at least one copy of chromosome band 1q42 were identified in the literature; all were astrocytic tumors and the majority were glioblastomas. It indicates a covert tumor suppressor gene in the region that is involved in astrocytic gliomas.

An audit programme for central venous catheter-associated infections.

Central venous catheters (CVC) are commonly associated with both localized and systemic infection. This paper describes an audit programme which was designed to review clinical practice associated with the insertion and subsequent care of CVC and their possible relationship to the development of infection. The programme was produced by a joint working group of the Hospital Infection Society and the Research Unit of the Royal College of Physicians and is subdivided into an audit of hospital practices and patient management associated with the use of CVC. It consists of a number of questions designed to evaluate all areas of CVC use, including the assessment of the incidence of associated local and systemic infection. Use of the questionnaire should allow policies for CVC insertion and care to be reviewed thereby, facilitating improvements, which may in turn reduce the incidence of infection associated with CVC.

Guidelines for good practice in central venous catheterization. Hospital Infection Society and the Research Unit of the Royal College of Physicians.

Central venous catheters (CVC) are commonly used in clinical practice and are associated with several complications, including early and late onset infection. In these guidelines, an outline of good practice for the use of CVC and the prevention of associated infections is presented. Definitions of both localized and systemic catheter-related sepsis are given. Subsequent good practice in relation to the insertion of CVC, including patient preparation, planned duration of catheterization, catheter materials and design of the CVC, are presented. Skin fixation and insertion site care, including the use of dressings and administration sets, as well as an approach to flow obstructions, are also reviewed. The clinical and microbiological diagnosis of catheter-related sepsis and its treatment is next presented. Finally, guidelines for CVC removal and replacement are given. The guidelines are designed to facilitate the development of good practice in the use of CVC, allowing appropriate protocols to be formulated and to reduce infection risk.

Fibrous hamartoma of infancy.

Fibrous hamartoma of infancy is an uncommon, benign, subcutaneous fibrous proliferation, usually found during the first 2 years of life. It predominantly affects healthy boys and can be found in almost any subcutaneous tissue. This tumor can cause much concern about malignancy because it is firm and may be fixed to underlying tissues. Despite the occasional local recurrence, the clinical course is benign and the prognosis is excellent. Treatment is by local excision. The diagnosis is made easily by the characteristic histologic features. In order to avoid the misdiagnosis of malignancy and unnecessary radical therapy, both surgeon and pathologist must be familiar with this entity. We have reviewed six cases of fibrous hamartoma of infancy seen over a 5-year period.

Long-term flow measurement: an assessment of the Siemens Servo 900B expiratory flowmeter.

The accuracy and linearity of three Siemens Servo 900B expiratory flowmeters have been assessed by comparison with a dry gas meter. Their performance was reassessed after 792,966 and 950 h respectively. The effects of changes in respiratory rate, relative humidity and oxygen concentration on the meters were studied. It was found that the meters were accurate and linear and that reliable measurements could still be made after long periods of continuous use. The meters were found to be less accurate at low respiratory rates. Relative humidity had little effect on flow measurement. Changes in oxygen concentration, and hence viscosity, led to errors of up to 16% in flow measurement.

Epidural and spinal anaesthesia and the use of anticoagulants.

Neurological injuries after epidural/spinal analgesia are a serious but uncommon problem. Spinal haematoma cause a proportion of these complications, and can be minimized by avoiding central nervous blockade in high-risk patients, especially those receiving anticoagulant therapy. Early recognition of spinal haematoma by basic neurological monitoring allows early intervention and improves outcome.

The use of computerized learning in intensive care: an evaluation of a new teaching program.

A computer-assisted learning program in respiratory intensive care was introduced into the undergraduate curriculum at University College Hospital. Educational effectiveness was assessed. This method of learning was found to be highly acceptable to students. The improvement in students knowledge of the subject was up to three times greater in those who used the computer program, than a control group of students who received only teaching by conventional means, (P = 0 X 016). The results of a questionnaire designed to elicit students' attitudes to this learning experience are discussed.

Primary rhabdomyosarcoma of the kidney. A light microscopic, immunohistochemical, and electron microscopic study.

Primary rhabdomyosarcoma of the kidney is a rare and highly aggressive tumor in the adult population. A case is reported in a 70-year-old woman with the diagnosis confirmed by immunohistochemistry and electron microscopy. This is the first case studied using the immunoperoxidase technique and the second with electron microscopic examination. To make a diagnosis of primary sarcoma, of the kidney, three criteria must be met: (1) a metastatic sarcoma must be ruled out; (2) the tumor must arise from renal parenchyma; and (3) a sarcomatoid variant of renal cell carcinoma needs to be excluded. The literature is reviewed and available clinical and pathologic details are summarized.

Intrauterine intussusception: case report and literature review.

Intussusception in the newborn is a unique clinical entity, and one of the most unusual causes of intestinal obstruction in infants. Its cause can be idiopathic, secondary to a local lesion or a complication of disease. Early diagnosis and treatment are important, because survival depends on them. The authors report a case of jejunal atresia secondary to intrauterine intussusception, followed by a literature review. Less than 30 cases have been adequately documented in the world literature. Eight reports from the literature are selected to highlight clues for early diagnosis, such as vomiting, with or without bile, abdominal distension and bloody stools, because of their prognostic implications. Intussusception is rare under the age of 3 months; the incidence is 0.3% in the neonatal period. Previous reports indicate that a confusing clinical picture has led to a delay in operation and a high mortality. The ultimate outcome depends on an acute awareness of the condition in the presence of the diagnostic clues in a newborn.

Long term effects of smoke inhalation in survivors of the King's Cross underground station fire.

BACKGROUND: In most accidents causing smoke inhalation only a few victims actually inhale the smoke. The fire at King's Cross provided an opportunity to assess the long term effects of smoke inhalation in a larger number of patients. METHODS: Fourteen survivors from the King's Cross underground station fire were assessed for respiratory disability six months after the disaster and 10 were reassessed at two years. All had inhaled substantial quantities of smoke and 10 had skin burns of differing severity. RESULTS: Six months after the fire nine survivors admitted to one or more symptoms, which included hoarseness (two cases), cough (five cases), and breathlessness (six cases); and a survivor with asthma noted a worsening of his symptoms. The remaining five denied new symptoms. Peak expiratory flow, spirometric indices, and transfer factor for carbon monoxide were within the predicted normal ranges. The mean residual volume, however, was greater than the predicted value and the mean maximum expiratory flow at 25% of vital capacity (V25) less than predicted, with no significant differences between smokers (n = 7) and non-smokers (n = 7). At least one of these ventilatory defects, suggesting small airways obstruction, was present in 11 survivors at six months and they had persisted in the seven patients who were reassessed at two years. CONCLUSION: Smoke inhalation may be associated with injury to the small airways.

A system for the continuous measurement of oxygen uptake and carbon dioxide output in artificially ventilated patients.

A continuous, non-invasive system is described for measuring oxygen uptake (VO2) and carbon dioxide output (VCO2) in mechanically ventilated patients. Inspiratory and mixed expiratory gas samples were pumped through fine-bore tubing to a remote mass spectrometer for analysis. The expiratory flow transducer of a Siemens Servo 900B ventilator was used for expiratory flow measurement and inspiratory flow was calculated from this using the Haldane transformation. A desk-top computer calculated VO2, VCO2 and respiratory quotient. The system has been validated against standard methods of gas analysis and flow measurement (VO2 mean difference -10 ml min-1: SD 9.13; VCO2 mean difference 8.12 ml min-1: SD 4.66). Comparison with Douglas bag measurements in patients has been made (VO2 mean difference 10.7 ml min-1: SD 9.8; VCO2 mean difference -1.07 ml min-1: SD 4.7).

Intravascular mixed venous oxygen tension monitoring. An analysis of electrode performance in 100 patients.

A lengthened umbilical artery catheter incorporating an oxygen electrode (Searle) was flow-guided to the pulmonary artery in 48 out of 62 attempts (77.4%). In the last 70 catheters used, electrode performance was evaluated over a total of 3687 h by comparison with an ABL2 (Radiometer) blood-gas analyser; 654 comparisons were made, of which 255 resulted in recalibration of the electrode output. When sampling intervals were within 6 h, in more than 80% of the comparisons the difference between in vivo and in vitro measurement was within +/- 0.4 kPa (+/- 3 mm Hg). Twenty-four electrodes were removed sooner than clinically indicated (mean useful life 48.5 h) because of failure of oxygen or pressure measurements.