Entries Tagged as 'Anaesthesia'
September 11th, 2009 · No Comments
Hypertonic saline in critical care: a review of the literature and guidelines for use in hypotensive states and raised intracranial pressure.
Anaesthesia. 2009 Sep;64(9):990-1003
Authors: Strandvik GF
Hypertonic saline has been in clinical use for many decades. Its osmotic and volume-expanding properties make it theoretically useful for a number of indications in critical care. This literature review evaluates the use of hypertonic saline in critical care. The putative mechanism of action is presented, followed by a narrative review of its clinical usefulness in critical care. The review was conducted using the Scottish Intercollegiate Guidelines Network method for the review of cohort studies, randomised-controlled trials and meta-analyses. The review focuses specifically on blood pressure restoration and outcome benefit in both haemorrhagic and non-haemorrhagic shock, and the management of raised intracranial pressure. Issues of clinical improvement and outcome benefit are addressed. Hypertonic saline solutions are effective for blood pressure restoration in haemorrhagic, but not other, types of shock. There is no survival benefit with the use of hypertonic saline solutions in shock. Hypertonic saline solutions are effective at reducing intracranial pressure in conditions causing acute intracranial hypertension. There is no survival or outcome benefit with the use of hypertonic saline solutions for raised intracranial pressure. Recommendations for clinical use and future directions of clinical research are presented.
PMID: 19686485 [PubMed - indexed for MEDLINE]
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Tags: Anaesthesia
Modelling the impact of an influenza A/H1N1 pandemic on critical care demand from early pathogenicity data: the case for sentinel reporting.
Anaesthesia. 2009 Sep;64(9):937-41
Authors: Ercole A, Taylor BL, Rhodes A, Menon DK
Projected critical care demand for pandemic influenza H1N1 in England was estimated in this study. The effect of varying hospital admission rates under statistical uncertainty was examined. Early in a pandemic, uncertainty in epidemiological parameters leads to a wide range of credible scenarios, with projected demand ranging from insignificant to overwhelming. However, even small changes to input assumptions make the major incident scenario increasingly likely. Before any cases are admitted to hospital, 95% confidence limit on admission rates led to a range in predicted peak critical care bed occupancy of between 0% and 37% of total critical care bed capacity, half of these cases requiring ventilatory support. For hospital admission rates above 0.25%, critical care bed availability would be exceeded. Further, only 10% of critical care beds in England are in specialist paediatric units, but best estimates suggest that 30% of patients requiring critical care will be children. Paediatric intensive care facilities are likely to be quickly exhausted and suggest that older children should be managed in adult critical care units to allow resource optimisation. Crucially this study highlights the need for sentinel reporting and real-time modelling to guide rational decision making.
PMID: 19645759 [PubMed - indexed for MEDLINE]
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Tags: Anaesthesia
B type natriuretic peptide–a diagnostic breakthrough in peri-operative cardiac risk assessment?
Anaesthesia. 2009 Feb;64(2):165-78
Authors: Rodseth RN
The B-type natriuretic peptides; B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, are increasing being used as biomarkers for the diagnosis, management and prognostication of cardiac failure, but their application in the peri-operative period is unclear. This review examines the current understanding of the role of B-type natriuretic peptides in both the operative and non-operative settings. Normal values, diagnostic thresholds, monitoring targets and significant prognostic levels are identified. Using this as a background, the role of B-type natriuretic peptides in the prediction of peri-operative mortality and morbidity is examined and potential confounders, such as renal failure and body mass index, which may impact significantly on the utility of the biomarkers, are discussed. Clinical recommendations with regard to its use are made and a research agenda is proposed for future peri-operative studies.
PMID: 19143695 [PubMed - indexed for MEDLINE]
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Tags: Anaesthesia
A survey of the use of ultrasound guidance in internal jugular venous cannulation.
Anaesthesia. 2008 Nov;63(11):1222-5
Authors: McGrattan T, Duffty J, Green JS, O’Donnell N
It has been that suggested the use of two dimensional (2D) ultrasound to facilitate placement of central venous cannulae in the internal jugular vein improves patient safety and reduces complications. Since the introduction of the National Institute for Clinical Excellence Technology Appraisal Guideline Number 49 in 2002, promoting the use of ultrasound in placement of internal jugular venous cannulae, utilisation of ultrasound has increased throughout the United Kingdom. We report the findings of a postal survey of 2000 senior anaesthetists in the United Kingdom which enquired about their use of ultrasound for internal jugular vein cannulae placement. Only 27% use 2D ultrasound as their first choice technique, although 35% use it as their first choice when teaching. There was no significant difference in practice between those working within a sub specialty in anaesthesia. There continues to be discrepancies between the application of the guideline and how senior anaesthetists both site and teach the placement of internal jugular vein central venous cannulae.
PMID: 19032257 [PubMed - indexed for MEDLINE]
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Metabolic acidosis in the critically ill: part 2. Causes and treatment.
Anaesthesia. 2008 Apr;63(4):396-411
Authors: Morris CG, Low J
The correct identification of the cause, and ideally the individual acid, responsible for metabolic acidosis in the critically ill ensures rational management. In Part 2 of this review, we examine the elevated (corrected) anion gap acidoses (lactic, ketones, uraemic and toxin ingestion) and contrast them with nonelevated conditions (bicarbonate wasting, renal tubular acidoses and iatrogenic hyperchloraemia) using readily available base excess and anion gap techniques. The potentially erroneous interpretation of elevated lactate signifying cell ischaemia is highlighted. We provide diagnostic and therapeutic guidance when faced with a high anion gap acidosis, for example pyroglutamate, in the common clinical scenario ‘I can’t identify the acid–but I know it’s there’. The evidence that metabolic acidosis affects outcomes and thus warrants correction is considered and we provide management guidance including extracorporeal removal and fomepizole therapy.
PMID: 18336491 [PubMed - indexed for MEDLINE]
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Metabolic acidosis in the critically ill: part 1. Classification and pathophysiology.
Anaesthesia. 2008 Mar;63(3):294-301
Authors: Morris CG, Low J
Metabolic acidaemia (pH < 7.35 not primarily related to hypoventilation) is common amongst the critically ill and it is essential that clinicians caring for such patients have an understanding of the common causes. The exclusive elimination routes of volatile (carbon dioxide), organic (lactic and ketone) and inorganic (phosphate and sulphate) acids mean compensation for a defect in any one is limited and requires separate provision during critical illness. We discuss the models available to diagnose metabolic acidosis including CO2/HCO3(-) and physical chemistry-derived (Stewart or Fencl-Stewart) approaches, but we propose that the base excess and anion gap, corrected for hypoalbuminaemia and iatrogenic hyperchloraemia, remain most appropriate for clinical usage. Finally we provide some tips for interpreting respiratory responses to metabolic acidosis and how to reach a working diagnosis, the consequences of which are considered in Part 2 of this review.
PMID: 18289237 [PubMed - indexed for MEDLINE]
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