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Biomedical subjects

A Bodenham

Publications and source records attributed to A Bodenham.

At least 19 recordsLinked to original sources
PubMed2007

Extracorporeal carbon dioxide removal using the Novalung in a patient with intracranial bleeding.

A neurosurgical patient who required repeated surgery for intracranial haematoma developed acute respiratory distress syndrome. Raised intracranial pressure proved difficult to manage whilst attempting to maintain optimal gas exchange. The resultant arterial partial pressure of carbon dioxide remained unacceptably high, and treatment by extracorporeal carbon dioxide removal was started. A pumpless arteriovenous interventional lung assist device (Novalung) was connected from the right femoral artery to left femoral vein and reduced the arterial carbon dioxide, corrected the respiratory acidosis and enabled control of the intracranial pressure. Subsequently the requirements for both respiratory and cardiovascular support were reduced. The patient made a complete neurological recovery.

Acidosis, Respiratory↗
PubMed2006

Bonfils semirigid endoscope for guidance during percutaneous tracheostomy.

We report on the use of the Bonfils semirigid scope for endoscopic guidance during percutaneous dilational tracheostomy. Forty patients requiring percutaneous dilational tracheostomy on the General or Neurosurgical Intensive Care Unit were enrolled in this study. We used the '45 degree curved distal tip' scope in the first 15 patients, evaluating its ease of use, optical quality of focus and image resolution as well as light intensity on a 10-point scale. We evaluated straight and curved versions of it in another 15 and 10 patients, respectively. We examined the impact on ventilation and cardiovascular parameters. In all patients (n = 40) visualisation of the procedure was satisfactory. There were no clinically significant changes in ventilatory or cardiovascular parameters. The image quality for most patients received a score of 7-10. The Bonfils scope provides a practical alternative to flexible bronchoscopes in this setting.

Adolescent↗
PubMed2004

Pharmacokinetics of remifentanil and its major metabolite, remifentanil acid, in ICU patients with renal impairment.

BACKGROUND: The pharmacokinetics of remifentanil, an opioid analgesic metabolized by non-specific esterases, and its principal metabolite, remifentanil acid (RA), which is excreted via the kidneys, were assessed as part of an open-label safety study in intensive care unit (ICU) patients with varying degrees of renal impairment. METHODS: Forty adult ICU patients with normal/mildly impaired renal function (creatinine clearance [CL(cr)] 62.9 (sd) 14.5 ml min(-1); n=10) or moderate/severe renal impairment (CL(cr) 14.7 (15.7) ml min(-1); n=30) were included. Remifentanil was infused for up to 72 h, at a starting rate of 6-9 microg kg(-1) h(-1) titrated to achieve a target sedation level, with additional propofol (0.5 mg kg(-1) h(-1)) if required. Intensive arterial sampling was performed for up to 72 h after infusion. Pharmacokinetic parameters obtained by simultaneous modelling of remifentanil and RA data were statistically compared between the two groups. RESULTS: Remifentanil pharmacokinetics were not significantly affected by renal status. RA clearance in the moderate/severe group was reduced to about 25% that of the normal/mild group (41 (29) vs 176 (49) ml kg(-1) h(-1), P<0.0001). Metabolic ratio, a predictor of the ratio of RA to remifentanil concentrations at steady state, was approximately eight-fold higher in the moderate/severe group relative to the normal/mild group (116 (110) vs 15 (4), P<0.0001). Maximum RA levels approached 700 ng ml(-1) in the moderate/severe group. CONCLUSIONS: Although RA accumulates in patients with moderate/severe renal impairment, pharmacokinetic modelling predicts that RA concentrations during a 9 microg kg(-1) h(-1) remifentanil infusion for up to 15 days would not exceed those reported in the present study, for which no associated prolongation of mu-opioid effects was observed.

Adolescent↗
PubMed2004

Provision of long-term venous access procedures by UK anaesthetists: a postal survey.

Long-term venous access is widely used in hospital and in the community for cancer chemotherapy, total parenteral nutrition and long-term administration of antibiotics. There is a large variety of catheters, ports and other devices designed to facilitate these treatments. A postal survey of anaesthetic departments in England, Wales, Scotland and Northern Ireland was undertaken to assess the role of anaesthetists in this area of clinical practice. Two hundred and fifteen out of 276 (78%) anaesthetic departments responded. Forty-three percent of departments (92 out of 215) provided some form of long-term vascular access service. Twenty-two percent of departments which provided this service (20 out of 92) had anaesthetists with sessional allocation for such procedures. Such work represents a significant workload for anaesthetic departments which is likely to increase over time.

Anesthesia Department, Hospital↗
PubMed2003

The provision and practice of renal replacement therapy on adult intensive care units in the United Kingdom.

This study surveyed the availability and current practice of renal replacement therapy on adult general intensive care units in the United Kingdom. Questionnaires were returned from 236 units (89%). Renal replacement therapy was provided by 212 (90%) of responding units, treating 9442 patients per year. Renal physicians were involved in the initiation and prescription of treatment in 22 (11%) units. Ninety-one units (43%) had no step down facility on-site for those patients still requiring renal replacement therapy but no longer requiring intensive care. Continuous techniques are used by the majority of units, most commonly, continuous veno-venous haemofiltration, with an ultrafiltration rate of 2000 ml.h-1. Fifty-eight units (28%) use haemofiltration as adjuvant treatment in septic shock. The provision and practice of renal replacement therapy is now an integral part of intensive care medicine in the United Kingdom.

Acute Kidney Injury↗
PubMed2003

Ultrasound imaging of the axillary vein--anatomical basis for central venous access.

BACKGROUND: The central veins that are usually cannulated are the jugular, subclavian, femoral and brachial. If subclavian catheterization is difficult using surface landmark techniques, we now use ultrasound to catheterize the infraclavicular axillary vein. This approach is not widely used and the ultrasound appearance has not been formally described. We examined the anatomical relationships of the axillary vessels to guide safe cannulation of the axillary vein. METHOD: In 50 subjects, we used ultrasound to examine the infraclavicular regions from below the mid-clavicular point and at 2 cm and 4 cm further laterally (described as the middle and lateral points) with the arms at 0 degrees, 45 degrees and at 90 degrees abduction. We took measurements at each point, with the artery and vein seen in cross-section. The depth from the skin, vessel diameters and the distance between the vessels was measured. The amount of overlap was scaled from 0 (no overlap) to 3 (complete overlap). We also recorded (if visible) the distance between the rib cage and axillary vein. A longitudinal image of the vein was also obtained. Angle of ascent (in relation to the skin), length and depth of the vein was measured. RESULTS: Axillary vessels were seen in 93% of images. The mean depth from skin to vein increased from 1.9 cm (range 0.7-3.7 cm) medially to 3.1 cm (1.1-5.6 cm) laterally. The venous diameter decreased from 1.2 cm (0.3-2.1 cm) medially to 0.9 cm (0.4-1.6 cm) laterally. The arterio-venous distance increased from 0.3 cm to 0.8 cm. Median arterio-venous overlap decreased from 2/3 (mode 3/3) to 0 (0). The distance from rib cage to vein increased from 1.0 cm to 2.0 cm. CONCLUSION: The axillary vein is an alternative for central venous cannulation and we present an anatomical rationale for its safe use. Less arterio-venous overlap and a greater distance between artery and vein and from vein to rib cage should provide an increased margin of safety for central venous cannulation.

Adult↗
PubMed2003

Safe removal of long-term cuffed Hickman-type catheters.

The use of long-term venous access devices is increasing. Most devices are anchored by a cuff, usually made of Dacron. The disadvantage of such cuffs is that a cut-down procedure is required for their removal. This article presents a simple technique for removal of Hickman-type catheters, emphasizing avoidance of complications.

Catheterization, Central Venous↗
PubMed2000

Ultrasonography of the femoral vessels in the groin: implications for vascular access.

The femoral artery and vein are commonly used for access to the circulation. Accidental puncture of one vessel whilst attempting to cannulate the other is a common complication. Identification of relevant surface anatomical landmarks and ultrasonography of both groins was performed on 50 consecutive adult patients admitted to the intensive care unit. In most patients there was overlap of the artery over the vein far closer to the inguinal ligament than conventional anatomical texts would indicate. The frequency and degree of overlap increased as the vessels descended distally towards the knee. Surface anatomical landmarks were not useful in predicting the underlying anatomy. The side-by-side relationship of artery and vein is commonest close to the inguinal ligament. Therefore, to avoid damage to the neighbouring vessel, percutaneous access should be undertaken just below the inguinal ligament.

Catheterization, Peripheral↗
PubMed1999

Portable ultrasonic scanning of the anterior neck before percutaneous dilatational tracheostomy.

We used portable ultrasound scans to identify relevant anatomical structures in the necks of 30 patients before percutaneous tracheostomy. We identified the tracheal midline, thyroid isthmus and blood vessels and located a safe level for needle insertion. Anterior jugular veins were seen in 15 patients; eight were near the midline and were considered vulnerable. Three veins were more than 4 mm in diameter and these larger vessels were electively ligated. Four patients had arteries which were considered vulnerable to damage. All patients underwent successful percutaneous tracheostomy. Portable ultrasound provides a simple method of screening for vulnerable blood vessels in the neck and for locating the midline before percutaneous tracheostomy. This method is particularly suitable for patients with landmarks that are difficult to visualise or palpate. Based on the ultrasonic findings we can make an informed decision about referral for surgical tracheostomy.

Adolescent↗
PubMed1999

Portable ultrasound for difficult central venous access.

Central venous catheterization can be difficult and can cause serious complications. Ultrasound-guided venous access is increasingly used but reports concern only routine cases. We performed a prospective observational study in 'difficult' or 'failed' procedures to assess the usefulness of ultrasound guidance. We used the technique in 33 patients; 23 had previous failed attempts or had suffered complications from such attempts. Ultrasound provided an anatomical reason for failure in 16 patients. Ten other patients were expected to be difficult before catheterization. Ultrasound identified a suitable site for catheterization in all 33 patients. Real-time ultrasound was used to successfully catheterize 22 patients. In nine patients, a surface landmark technique was used, which failed in three patients. In these three patients, ultrasound guidance allowed successful cannulation. Ultrasound guidance is a useful technique to aid central venous access when difficulties or complications have been encountered or anticipated.

Adolescent↗
PubMed1998

Comparison of air tonometry with gastric tonometry using saline and other equilibrating fluids: an in vivo and in vitro study.

OBJECTIVE: 1) To compare saline gastric tonometry monitoring with air tonometry (Tonocap) in a group of general ICU patients. 2) An in vitro investigation of the performance of other fluids used in gastric tonometry and to assess the effects of variation of temperature and carbon dioxide concentration within the range encountered in clinical use. DESIGN: a) A prospective, observational study in ICU patients b) A comparative laboratory study. SETTING: The general Intensive Care Unit (ICU) and the laboratory at Leeds General Infirmary. PATIENTS AND PARTICIPANTS: Nine patients in the general ICU with severe sepsis or septic shock. MEASUREMENTS AND RESULTS: In vivo comparison of saline and air tonometry demonstrated a difference between the two techniques. Bland & Altman analysis showed a mean bias in the measurement of gastric PCO2 of 1.88 kPa with a precision of 1.22 kPa, with saline giving the lower result. In vitro, saline, air (Tonocap), gelatin and heparinised blood were used, at temperatures of 33-42 degrees C and at carbon dioxide concentrations of 4-8 kPa. While gelatin and blood gave unpredictable results, dependent on temperature and carbon dioxide concentration, air tonometry gave highly reproducible results. A consistent bias between the results with saline and air tonometry was seen over the range of temperatures and carbon dioxide (CO2) concentrations studied. The mean bias was 0.85 kPa with a precision of 0.40 kPa, saline consistently giving lower results. CONCLUSIONS: There are clinically significant differences in values for gastric mucosal PCO2 measured by air tonometry and saline tonometry both in vivo and in vitro.

Acidosis↗
PubMed1996

Total vitamin C, ascorbic acid, and dehydroascorbic acid concentrations in plasma of critically ill patients.

Plasma concentrations of the antioxidant vitamin ascorbic acid were measured by high-performance liquid chromatography in critically ill patients in whom the excessive generation of reactive oxygen species could compromise antioxidant defense mechanisms. Median concentrations of both total vitamin C (ascorbic acid and dehydroascorbic acid) and ascorbic acid in these patients were < 25% (P < 0.001) of the values found in healthy control subjects and in subjects in two other disease groups (diabetes, gastritis) in which reactive oxygen species are reported to be increased. The low values could not be explained by age, sex, intake, or treatment differences, but were associated with the severity of the illness and were not prevented by the use of parenteral nutrition containing ascorbic acid. In addition, the vitamin was less stable in blood samples taken from critically ill patients than in similar samples from subjects in the other groups. The findings indicate that antioxidant defenses could be considerably compromised in these very sick patients. If this reduces the patient's capacity to scavenge reactive species, then the potential of these species to damage DNA and lipid membranes could be increased and compromise recovery.

Adult↗