Masters Degrees (Anaesthesiology and Critical Care)

Permanent URI for this collection

https://scholar.sun.ac.za/handle/10019.1/3549

Browse

Browsing Masters Degrees (Anaesthesiology and Critical Care) by browse.metadata.advisor "Smit, Marli"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Blood pressure measurement in the obese patient: a comparison between non-invasive proximal forearm and radial arterial blood pressure measurement
    (Stellenbosch : Stellenbosch University, 2017-12) Verkhovsky, Anna; Smit, Marli; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Anesthesiology and Critical Care.
    ENGLISH ABSTRACT: ABSTRACT Background: South Africa has a high prevalence of obese adults. When these (obese) individuals present to a health care facility, blood pressure measurement will play an important role during routine medical evaluation. Accurate non-invasive blood pressure monitoring is a challenge in obese individuals secondary to inaccurate readings associated with inappropriate cuff size, structural differences of the upper arm as well as short upper arm length. Our aim was to identify an accurate, affordable, minimally invasive and low-risk blood pressure measurement modality in obese patients. Methods: This study included 30 patients with a body mass index of greater or equal to 30 kg/m2 presenting for surgery or staying in a High Care Unit at Tygerberg Hospital. In all of these patients, an intra-arterial line was included as part of their routine care. We compared the non-invasive (mean, systolic and diastolic) blood pressures readings from the proximal forearm, with the gold standard, being intra-arterial blood pressure readings. Results: There was poor agreement between the mean intra-arterial blood pressure measurement and the noninvasive blood pressure (NIBP) measured at the forearm. The mean NIBP measured at the forearm overestimated the intra-arterial blood pressure reading by 2% (±8.1 %. P 0.031). The computed upper and lower levels of agreement between the 2 methods ranged from -19.3 to 15.2%. Systolic NIBP measurements at the forearm over-estimated the IABP measurements by 0.9% (P 0.295). Upper and lower levels of agreement between the 2 methods ranged from -16.4 to 14.7%. Larger discrepancies between the two methods were observed for diastolic blood pressure measurements with a mean difference of -5.8% (P <0.0001). Conclusion: We cannot recommend that the forearm NIBP reading be used as an accurate, non-invasive and cost effective substitute to measure blood pressure in obese patients.
  • Thumbnail Image
    Item
    The prevalence of thrombocytopenia at a primary care HIV clinic in South Africa - possible implications for neuraxial anaesthesia
    (Stellenbosch : Stellenbosch University, 2017-12) Steadman, Carl; Smit, Marli; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Anaesthetics and Critical Care.
    ENGLISH ABSTRACT: South Africa has a high incidence of Human Immunodeficiency Virus (HIV) infection, and many of these patients will require surgery during their lives. The exact prevalence of thrombocytopenia in South African, HIV-infected patients (naïve/non anti-retroviral therapy naïve) are unknown. The reported global prevalence of thrombocytopenia in HIV positive patients ranges between 5.5 to 50% 17, 18. Neuraxial anaesthesia is contraindicated in patients with platelet counts of <75 x 109/L, due to the risk of neuraxial haematoma. The large variation in practice (in South Africa) in terms of preoperative special investigations (especially platelet count) in this patient population suggests that patients are either under investigated, or that unnecessary investigations are performed; with cost and time implications. This wide range in thrombocytopenia prevalence, together with the anaesthetic implications secondary to thrombocytopenia was the motivation behind us conducting an audit to determine the prevalence of thrombocytopenia in HIV positive patients. Our primary outcome was to determine the prevalence of thrombocytopenia in HIV-positive patients attending a primary care HIV clinic in the Western Cape, South Africa. Secondary outcomes were to: 1. Determine if there is any correlation between CD4 count and platelet count. 2. Determine what the influence of ART on platelet count is. 3. To make informal proposals regarding pre-operative special investigations (specifically platelet count) in the HIV positive patients. Our study, consisting of 1,410 patients, provided the following important results: The median CD4 count was 281 +/- 199 cells / mm3. Thirty-one percent of patients had a CD4 count of < 200 cells / mm3. The median platelet count was 270 +/- 100x109/L. The platelet count was < 150 x 109/L (thrombocytopenia) in 6.5%, and < 75 x 109 /L (severe thrombocytopenia) in 0.7% of participants. Thrombocytopenia was more common in patients with a CD4 count < 200 cells/mm3 (p <0.001) and in ART naïve patients (p = 0.02). However, there was no connection between severe thrombocytopenia and a CD4 count of < 200 cells / mm3 (p = 0.36) or ARV naivety (p = 0.66) Infection and malignancy had no significant impact on thrombocytopenia (p = 0.66, Fischer's exact 0.3) nor severe thrombocytopenia (p = 0.99, Fischer's exact 0.5). Conclusion: In this descriptive study, we found that the prevalence of severe thrombocytopenia to be very low (0.7%). We cannot make statistically supported deductions regarding this result because the prevalence of thrombocytopenia in the general population is unknown, and our study did not have a control group. However, we will propose that the following be kept in mind regarding preoperative special investigation decision making in HIV positive patients: 1. The incidence of neuraxial hematomas has not increased in conjunction with the increase in HIV positive patients, 2. The costs associated with special investigations. 3. The low prevalence of severe thrombocytopenia. 4. The lack of literature to support a safe cut-off for platelet count for neuraxial anaesthesia.