Research Articles (Anaesthesiology and Critical Care)


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    Comparison of hemoglobin measurements by 3 point-of-care devices with standard laboratory values and reliability regarding decisions for blood transfusion
    (Lippincott, Williams & Wilkins, 2020-08) Johnson, Marianne; Marwick, Peter C.; Coetzee, Johan F.
    BACKGROUND: We compared the accuracy of 3 point-of-care testing (POCT) devices with central laboratory measurements and the extent to which between-method disagreements could influence decisions to transfuse blood. METHODS: Hemoglobin concentrations [Hb] were measured in 58 adult patients undergoing cardiothoracic surgery using 2 Ilex GEM Premier 3500 blood gas analyzers (BG_A and BG_B) and a HemoCue Hb-201+ device (HemoCue). Measurements were compared with our central laboratory’s Siemens Advia 2120 flow cytometry system (laboratory [Hb] [Lab[Hb]]), regarded as the gold standard. We considered that between-method [Hb] differences exceeding 10% in the [Hb] range 6–10 g/dL would likely erroneously influence erythrocyte transfusion decisions. RESULTS: The 70 Lab[Hb] measurements ranged from 5.8 to 16.7 g/dL, of which 25 (36%) were <10.0 g/dL. Measurements by all 4 devices numbered 57. Mean POCT measurements did not differ significantly (P > .99). Results of the Bland–Altman analyses revealed statistically significant bias, with predominant underestimations by all 3 POCTs predominating. HemoCue upper and lower limits of agreement (LOA) were narrower, and the 95% confidence intervals (95% CIs) of the LOAs did not overlap with those of BG_A and BG_B. Similarly, a narrow mountain plot demonstrated greater precision for the HemoCue. Comparing BG_A with BG_B revealed no bias and narrow LOA. Error grid analysis within the [Hb] range 6–10 g/dL revealed that 5.3% of HemoCue measurements were beyond the permissible 10.0% error zone in contrast to 19.0% and 16.0% of the blood gas measurements. Possible inappropriate transfusion decisions based on POCT values generally erred toward unnecessary transfusions. Calculations of Cohen κ statistic indicated better chance-corrected agreement between HemoCue and Lab[Hb] regarding erythrocyte transfusions than the blood gas analyzers. CONCLUSIONS: All 3 POCT devices underestimated the Lab[Hb] and cannot be used interchangeably with standard laboratory measurements. BG_A and BG_B can be considered to be acceptably interchangeable with each other. Whereas the HemoCue had little bias and good precision, the blood gas analyzers revealed large bias and poor precision. We conclude that the tested HemoCue provides more reliable measurements, especially within the critical 6–10 g/dL range, with reduced potential for transfusion errors. Decisions regarding erythrocyte transfusions should also be considered in the light of clinical findings.
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    The Critical Care Society of Southern Africa Consensus Guideline on ICU triage and rationing (ConICTri)
    (Health and Medical Publishing Group (HMPG), 2019-08) Joynt, G. M.; Gopalan, D. P.; Argent, A. A.; Chetty, S.; Wise, R.; Lai, V. K. W.; Hodgson, E.; Lee, A.; Joubert, I.; Mokgokong, S.; Tshukutsoane, S.; Richards, G. A.; Menezes, C.; Mathivha, R. L.; Espen, B.; Levy, B.; Asante, K.; Paruk, F.
    Background: In South Africa (SA), administrators and intensive care practitioners are faced with the challenge of resource scarcity as well as an increasing demand for intensive care unit (ICU) services. ICU services are expensive, and practitioners in low- to middle-income countries experience the consequences of limited resources daily. Critically limited resources necessitate that rationing and triage (prioritisation) decisions are routinely necessary in SA, particularly in the publicly funded health sector. Purpose: The purpose of this guideline is to utilise the relevant recommendations of the associated consensus meeting document and other internationally accepted principles to develop a guideline to inform frontline triage policy and ensure the best utilisation of adult intensive care in SA, while maintaining the fair distribution of available resources. Recommendations: An overall conceptual framework for the triage process was developed. The components of the framework were developed on the basis that patients should be admitted preferentially when the likely incremental medical benefit derived from ICU admission justifies admission. An estimate of likely resource use should also form part of the triage decision, with those patients requiring relatively less resources to achieve substantial benefit receiving priority for admission. Thus, the triage system should maximise the benefits obtained from ICU resources available for the community. Where possible, practical examples of what the consensus group agreed would be considered appropriate practice under specified South African circumstances were provided, to assist clinicians with practical decision-making. It must be stressed that this guideline is not intended to be prescriptive for individual hospital or regional practice, and hospitals and regions are encouraged to develop specified local guidelines with locally relevant examples. The guideline should be reviewed and revised if appropriate within 5 years. Conclusion: In recognition of the absolute need to limit patient access to ICU because of the lack of sufficient intensive care resources in public hospitals, this guideline has been developed to guide policy-making and assist frontline triage decision-making in SA. This document is not a complete plan for quality practice, but rather a template to support frontline clinicians, guide administrators and inform the public regarding appropriate triage decision-making.
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    Improving perioperative pain management: a preintervention and postintervention study in 7 developing countries
    (Wolters Kluwer Health, 2019-01-01) Zaslansky, Ruth; Chapman, C. Richard; Baumbach, Philipp; Bytyqi, Adem; Lopes, Jose M. Castro; Chetty, Sean; Kopf, Andreas; Li, Li; Ming, Lim Ern; Olawoye, Olayinka; Parico, Jane Rizza; Soyannwo, Olaitan; Stamenkovic, Dusica; Wang, Hongwei; Meissner, Winfried
    Introduction: The burden of untreated postoperative pain is high. Objective: This study assessed feasibility of using quality improvement (QI) tools to improve management of perioperative pain in hospitals in multiple developing countries. Methods: The International Pain Registry and Developing Countries working groups, from the International Association for the Study of Pain (IASP), sponsored the project and PAIN OUT, a QI and research network, coordinated it, and provided the research tools. The IASP published a call about the project on its website. Principal investigators (PIs) were responsible for implementing a preintervention and postintervention study in 1 to 2 surgical wards in their hospitals, and they were free to choose the QI intervention. Trained surveyors used standardized and validated web-based tools for collecting findings about perioperative pain management and patient reported outcomes (PROs). Four processes and PROs, independent of surgery type, assessed effectiveness of the interventions. Results: Forty-three providers responded to the call; 13 applications were selected; and PIs from 8 hospitals, in 14 wards, in 7 countries, completed the study. Interventions focused on teaching providers about pain management. Processes improved in 35% and PROs in 37.5% of wards. Conclusions: The project proved useful on multiple levels. It offered PIs a framework and tools to perform QI work and findings to present to colleagues and administration. Management practices and PROs improved on some wards. Interpretation of change proved complex, site-dependent, and related to multiple factors. PAIN OUT gained experience coordinating a multicentre, international QI project. The IASP promoted research, education, and QI work.
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    Anaesthetic induction with propofol: How much? How fast? How slow? What determines anesthetic induction dose? It’s the Front-End Kinetics, Doctor!
    (Medpharm Publications, 2019) Coetzee, J. F.
    ENGLISH ABSTRACT: It has long been realised that linear dosing according to total body weight (TBW) results in overdosing obese patients and under-dosing small children. Injected drug doses calculated on a body weight basis work well only for patients of normal habitus. As long ago as 1969, in a study of induction doses of thiopentone,  ulfsohn and Joshi2 concluded that thiopentone was better administered according to lean body mass (LBM) than to TBW. They reasoned that endomorphic somatotypes required less thiopentone than mesomorphs and ectomorphs of the same TBW, because they had less LBM. They pointed out that there is a strong association between LBM, cardiac output and basal metabolic rate, and suggested that the LBM contained the “pharmacologically active mass”. Obese patients can perhaps be loosely regarded as ordinary individuals entrapped in a cocoon of fat into which hardly any injected drug is distributed. However the LBM of obese persons also increases as they accumulate fat, mainly due to increased muscle mass, as well as  enlargement of other organs and blood volume. The dilemma is that LBM does not increase at the same rate as the increase in fat. Thus, although we know that they need more drug than normal-weight patients, how much more is often uncertain.
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    Anaesthetic management of a three-month-old baby for cervical limited dorsal myeloschisis repair using propofol and alfentanil infusions guided by pharmacokinetic simulation software : case report
    (Medpharm Publications, 2019) Coetzee, E.; Gray, R.; Hollmann, C.; Enslin, N. J. M.; Coetzee, J. F.
    ENGLISH ABSTRACT: We present an uncommon case of limited dorsal myeloschisis in a 3-month-old infant requiring repair guided by intraoperative neuromonitoring (IONM) and therefore avoidance of volatile anaesthetic agents. The case presented challenges in positioning, airway management, a lack of age appropriate pharmacokinetic models in target-controlled infusion (TCI) syringe pumps and unavailability of remifentanil, considered to be an essential drug in this setting. We overcame these challenges using manually controlled infusions of propofol and alfentanil guided by pharmacokinetic simulation software (Stelsim).