“What knob is this?” – Intensive care unit ventilation for the non-intensivist

Indications for intensive care unit (ICU) mechanical ventilation differ from those for intraoperative mechanical ventilation. Always, the fundamental goal is the provision of life-sustaining oxygen saturation, with the avoidance of ventilator-induced trauma. Once past the initial stabilisation phase, a high priority must be placed on liberating the patient from mechanical ventilation. Encouraging patient-ventilator synchrony may accelerate this. Modern ICU ventilators have a number of modes and tools which may be useful in facilitating both initial mechanical ventilation optimisation and accelerate subsequent weaning, and these are generically reviewed within a discussion of the general conduct of ICU ventilation.Keywords: mechanical ventilation, lung protection, ventilator weaning, ventilator synchron

Intraoperative point-of-care testing

Point-of-care devices offer an increasing number of analytical tests more quickly than laboratory analysis, but clinicians must be aware of the limitations of these devices, especially for critical threshold-level decisions. Glucometers are susceptible to a wide range of errors, and only a few haemoglobin-measuring devices have accuracy approaching that of laboratory analysis. Activated coagulation time remains a useful but error-prone test for heparin effects. Thromboelastography and thromboelastometry offer insight into coagulation defects superior to conventional assays. Multi-function testers provide cardiac enzyme and lactate analysis that is becoming vital for intraoperative decision-making.Keywords: benefits; risks; shock; inotropes; vasopressor

The benefits and risks of vasoactive agents

Current shock resuscitation strategies require titration of fluid in combination with inotropes and vasopressors to counteract the actual pattern of circulatory abnormality in the patient, and to restore the circulation to a level that is adequate to prevent organ ischaemia. Used incorrectly or in excessive doses, vasoactive agents may cause patient harm. The mechanisms of shock, appropriate resuscitation goals, and some aspects of how common available vasoactive agents in South Africa can be used for optimal safely to help to achieve these goals are discussed.Keywords: benefits; risks; shock; inotropes; vasopressor

Mineralogical and geochemical studies of some witwatersrand gold ores with special reference to the nature of the phyllosilicates

A thesis submitted for the degree of Doctor of Philosophy in the Faculty of Science at the University of the Witwatersrand.The present thesis is divided into three parts. The study described in Part I arose out of a request by the Chamber of Mines Mining Research Laboratory to the National Institute for Metallurgy to undertake a preliminary study of whether it would be feasible, in Witwatersrand conglomerates, to carry out rapid delimitation of areas rich in gold and/or uranium at the rock face, a procedure which would permit areas of rich ore to be removed selectively by means of the "rock-cutter". The approach adopted in this study was essentially geochemical, while conventional mineralogical techniques (macro-auto radiographs , thin section and polished section analyses) provided a control. The samples were drawn from the Vaal Reef at Hartebeestfontein and Zandpan and from the Ventersdorp Contact Reef at Venterspost, and were analysed quantitatively for gold, silver, uranium, pyrite, muscovite, pyrophyllite, chlorite, quartz, iron, potassium, nickel, titanium, zirconium and chromium. The intensity of the interrelationships between the elements and minerals analysed for was examined statistically by means of correlation covariance and factor analysis programmes written for an IBM 360/50 digital computer. A sympathetic relationship -- defined as significant positive correlation (with a correlation coefficient r> 0. 7) -- was found to exist between gold and uranium in both the Vaal Reef and Ventersdorp Contact Reef samples. These findings suggest that gold and uranium can be removed Simultaneously by means of the rock-cutter, and that radioactivity can be used as an indicator for on-site delimitation of areas rich in gold. In the course of the study described in Part I, it became evident that little detailed mineralogical work had ever been done on the phyllosilicates occurring in the Witwatersrand System. Accordingly, certain phyllosilicates from Witwatersrand conglomerate bands and other sources were examined in detail, this study being described in Part II of the present thesis. This study called for detailed chemical, optical, X-ray crystallographic, infra-red, differential thermal and thermogravimetric analyses, the results of which are presented. The findings were examined in the light of variolls classification schemes that have bep proposed for the phyllosilicates. This investigation revealed the need for a universally acceptable system of classification for the phyllosilicates, which should preferably be drawn up under the auspices of the International Mineralogical Association to avoid the confusion that exists at present. Part III of the present thesis is devoted to a discussion and description of various analytical techniques that had to be modified or developed to meet th8 requirements of the studies described in Parts I and II. The techniques described include: (1) An X-ray diffraction method which was developed for the quantitative analysis of pyrite, muscovite, pyrophyllite, chlorite and quartz in crushed ore from Witwatersrand conglomerates. This method makes use of novacul iie as an external standard and of binary mixtures as analytical standards, and had a mean absolute error of 1. 1 %. This method may be expanded to permit analysis of an n-component mixture. (2) A whole rock pressed powder technique of X-ray fluorescence analysis which was used for the quantitative determination of iron, potassium, nickel, titanium, zirconium and chromium. This method makes use of internstional rock standards as external standards. Six computer programmes used for the computation of the analytical results and in the statistical and crystallographic calculations are also presented in Part III.AC201

Concentrating on the right measures

The continued use of “percent” in the labelling and description of many drugs used in the field of anaesthesia is an ongoing source of errors. As part of the modern drive towards safety in medicine it is proposed that the standard of labelling according to mass of the drug per millilitre be universally adopted.Keywords: drug dosage calculations, drug labelling, medication error

Die Wahl des Geburtsorts - Eine Analyse der Entscheidungskriterien schwangerer Frauen am Beispiel des Hebammenkreißsaals

The concept of midwife-managed delivery units (MDUs) is relatively new in Germany. The first one was implemented in the city of Bremerhaven in 2003. This concept offers midwifery delivery care while acknowledging the fact that 98% of the childbearing women in Germany decide to give birth in a hospital. This approach is also supposed to counteract the medicalization of clinical obstetric care and to thereby reduce the over and inappropriate utilization of health care. So far, it is unknown whether the MDU meets the needs of pregnant women in Germany. Aim The aim of the study was to explore the decision making criteria of pregnant women to give birth at a MDU or at the standard delivery unit. Methods A longitudinal qualitative study was carried out. Twenty-nine women, who planned to give birth at a hospital in Bremerhaven were interviewed during pregnancy and after puerperium. Participation was voluntary and informed consent was obtained in order to meet ethical requirements. The interviews where conducted using a list of questions about several aspects of delivery care. It was also of interest, if women were able to identify the delivery unit, which fits their individual needs best. At the post-delivery interview, any changes in deciding for one or the other concept of care were assessed. The interviews were analysed using content analysis (Mayring 2000). The study was carried out from February 2004 until March 2007. Results Aspects of security and being self-determined influenced the choice of the delivery unit. Another important aspect was the desired health care provider. Dependent on the individual perception, whether pregnancy and birth were seen as a risky or as a normal life event, women chose the standard medical care or the midwifery care. The decision was persistent before and after birth in most cases. Conclusions A positive birth experience seems to depend more on a trustworthy relationship with the delivery-midwife, than on the chosen concept. The continuity of care benefits from several offers like acupuncture or midwife consultations which therefore contribute to a good basis for a trustworthy relationship between woman and midwife. In order to achieve demedicalisation in clinical birth settings, it is necessary to develop approaches that involve not only professionals, but also users

Gastric Choristoma of the Oropharynx

Heterotopic gastric mucosa tissue is also called gastric choristoma, and this type of lesion can be found anywhere in the alimentary tract. However, gastric choristoma in the pharynx is very rare; only 10 cases of pharyngeal gastric choristoma have been reported in the English medical literature. A 32-yr-old woman was referred to our institution for the evaluation of a large mass that originated from the posterior wall of the oropharynx. The mass did not cause any symptoms except for the occasional sensation of a foreign body. Gadolinium-enhanced T1 weighted imaging showed a 5 cm-sized mass with central enhancement and hypointense portions, yet the radiological diagnosis was not clear. Transoral mass excision was performed with using electrocautery for making the diagnosis and for treating the mass. The microscopic analysis revealed gastric choristoma

Heart rate variability predicts 30-day all-cause mortality in intensive care units

Background: Autonomic nervous function, as quantified by heart rate variability (HRV), has shown promise in predicting clinically important outcomes in the critical care setting; however, there is debate concerning its utility. HRV analysis was assessed as a practical tool for outcome prediction in two South African hospitals and compared with Acute Physiology and Chronic Health Evaluation II (APACHE II) scoring.Method: In a dual centre, prospective, observational cohort study of patients admitted to the intensive care units (ICU) of two hospitals in KwaZulu-Natal, South Africa frequency domain HRV parameters were explored as predictors of: all-cause mortality at 30 days after admission; ICU stay duration; the need for invasive ventilation; the need for inotrope/vasopressor therapy; and the need for renal replacement therapy. The predictive ability of HRV parameters against the APACHE II score for the study outcomes was also compared.Results: A total of 55 patients were included in the study. Very low frequency power (VLF) was shown to predict 30-day mortality in ICU (odds ratio 0.6; 95% confidence interval 0.396–0.911). When compared with APACHE II, VLF remained a significant predictor of outcome, suggesting that it adds a unique component of prediction. No HRV parameters were predictive for the other secondary outcomes.Conclusion: This study found that VLF independently predicted all-cause mortality at 30 days after ICU admission. VLF provided additional predictive ability above that of the APACHE II score. As suggested by this exploratory analysis larger multi-centre studies seem warranted.Keywords: APACHE II, autonomic nervous system, critical care, heart rate variability, mortalit

Intra-operative cell salvage in South Africa: Feasible, beneficial and economical

Background. Healthcare services in KwaZulu-Natal (KZN) frequently experience shortages of blood products. Alternatives to traditional blood sources are needed. One possibility is cell salvage and autologous blood transfusion. Few data exist relating to their use in the South African context.Objectives. To ascertain whether cell salvage (CS) is beneficial, feasible and economical in our setting, with the anticipation that results would excite further studies and potentially change current practice and improve existing protocols. Methods. This study reviewed current intraoperative Cell Saver use at Grey’s and Edendale hospitals in Pietermaritzburg, KZN. Current practices were observed and compared with the costs of the equivalent amount of red cell concentrate (RCC) purchased from the South African National Blood Service (SANBS). All cases of Cell Saver usage over a 1-year period from July 2012 to June 2013 were analysed. Results. The total volume of blood transfused from CS was 55 735 ml, approximately equivalent to 186 RCC units. The comparative cost of equivalent units of RCC from SANBS was R258 445. The total cost of Cell Saver disposables during the study period was R206 047, or R263 478 when Cell Saver machine depreciation costs were included. More than one CS blood unit was available for transfusion in 66% of cases. No additional staff were required to operate the Cell Saver, which was successfully used by medical officers. Conclusions. This study showed that intraoperative CS use is feasible, has potential patient benefit by reducing blood bank blood transfusion, and is financially comparable to purchasing the equivalent number of SANBS RCC.