Comparison of erector spinae plane and transversus abdominis plane block for postoperative analgesia after caesarean delivery under spinal anaesthesia: A randomised controlled trial.

BACKGROUND: Truncal blocks contribute to multimodal analgesia that enhances early recovery after caesarean delivery. The transversus abdominis plane (TAP) block is an established technique that offers somatic abdominal wall analgesia. The erector spinae plane (ESP) block is a fascial plane technique that may offer additional visceral analgesic effects. This study hypothesized that ESP block would offer superior analgesic efficacy to TAP block in women undergoing caesarean delivery under spinal anaesthesia. METHODS: Sixty-six ASA physical status grade 1-3 (≥18 years) patients undergoing elective caesarean delivery under spinal anaesthesia were randomly allocated to receive either bilateral ultrasound-guided TAP (N = 33) or ESP blocks at the T9 vertebral level (N = 35). The primary outcome measure was 24-hour cumulative morphine consumption. The secondary outcomes included time to first analgesic request, duration of block placement, numeric rating scale (NRS) pain scores at rest and movement, effect of pain on activities of daily living (ADLs) and care for the infant, patient analgesic satisfaction, frequency and severity of opioid-related side effects. RESULTS: There was no statistically significant difference in mean (95% CI) 24-hour cumulative morphine consumption between groups: 32.0 (27.0 to 37.0) mg with TAP versus 27.0 (19.9 to 34.0) mg with ESP (p = 0.16). The mean (SD) duration of block placement was longer for ESP than for TAP blocks (10.7 (2.2) minutes versus 9.0 (2.5) minutes; p = 0.004). There were no significant differences in the other secondary outcomes. CONCLUSION: This study found similar postoperative opioid use and analgesic efficacy between ESP and TAP block after caesarean delivery performed under spinal anaesthesia. TRIAL REGISTRATION: South African National Clinical Trial Registry (DOH-27-102022-5278): https://sanctr.samrc.ac.za/TrialDisplay.aspx?TrialID=8100, Pan African Clinical Trials Registry (PACTR202301645957324): https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=24267.

Underdiagnosis of hypertension and diabetes mellitus in South Africa.

BACKGROUND: Hypertension and diabetes mellitus (DM) are major causes of natural death in South Africa (SA). Underdiagnosis of these treatable diseases would hamper efforts to improve their management and hence reduce morbidity and mortality. OBJECTIVES: To assess the level of underdiagnosis of hypertension and DM in SA. METHODS: Data from adult participants (≥15 years) in the 2016 South African Demographic and Health Survey, which draws a nationally representative sample of the population, was used. Using these data, the prevalence of hypertension and DM was assessed at the time of the study using objective criteria (hypertension: systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg; DM: glycated haemoglobin (HbA1c) ≥6.5%), and disease prevalence based on participant recall of having ever received a diagnosis of hypertension or DM from a healthcare professional. The difference between the objectively measured prevalence of the diseases and the prevalence based on recall was used to assess the level of underdiagnosis. RESULTS: Of 10 336 adult participants who answered the question on the recall of a diagnosis, 8 092 had their blood pressure measured, and 6 740 had HbA1c assessed. The prevalence of hypertension based on recall was 18.9% (95% confidence interval (CI) 17.7 - 20.1), while the prevalence using blood pressure measurements was 37.1% (95% CI 35.3 - 38.9). Therefore, 49% of cases of hypertension are likely to be undiagnosed (~7.1 million people). The prevalence of DM based on recall was 4.5% (95% CI 3.9 - 5.1), and 11.4% (95% CI 10.4 - 12.4) based on HbA1c values. Therefore, 61% of cases of DM are likely to be undiagnosed (~2.7 million people). CONCLUSIONS: There is significant underdiagnosis of hypertension and DM in SA. The underdiagnosis of these two treatable conditions, which have high morbidity and mortality, has major population health implications.

TNF haplotypes in a Southern African population resemble those seen in Caucasians and Asians.

Haplotypes spanning the tumor necrosis factor (TNF) gene block in the central major histocompatibility complex were defined in a Southern African population using 31 single-nucleotide polymorphisms. Twenty haplotypes accounted for 91.8% of the cohort. The haplotypes matched those described previously in Caucasian and Asian populations, supporting the hypothesis that TNF block haplotypes are ancient and highly conserved. They are presented here as a tool for disease-association studies.

A polymorphism in IL4 may associate with sensory neuropathy in African HIV patients.

INTRODUCTION: Animal and in vitro models of HIV-associated sensory neuropathy suggest an inflammatory etiology. Previous genetic association studies of HIV-SN have been in small Caucasian or Asian cohorts. We assessed cytokine single nucleotide polymorphisms (SNPs) in a Black Southern African cohort. METHOD: 342 black HIV-positive Southern Africans were recruited. 190 individuals had HIV-associated sensory neuropathy and 152 did not. DNA samples from all participants were genotyped for cytokine SNPs identified in studies of HIV disease and/or neuropathy. RESULTS: IL4-590*T associated with an increased prevalence of HIV-SN including following correction for age, height and CD4 T-cell count. No other cytokine SNPs assessed displayed an association. DISCUSSION: We identified a novel association between IL4-590*T and HIV-SN in African HIV-positive patients which warrants further investigation.

Clinical practice guidelines for management of neuropathic pain: expert panel recommendations for South Africa.

Neuropathic pain (NeuP) is challenging to diagnose and manage, despite ongoing improved understanding of the underlying mechanisms. Many patients do not respond satisfactorily to existing treatments. There are no published guidelines for diagnosis or management of NeuP in South Africa. A multidisciplinary expert panel critically reviewed available evidence to provide consensus recommendations for diagnosis and management of NeuP in South Africa. Following accurate diagnosis of NeuP, pregabalin, gabapentin, low-dose tricyclic antidepressants (e.g. amitriptyline) and serotonin norepinephrine reuptake inhibitors (duloxetine and venlafaxine) are all recommended as first-line options for the treatment of peripheral NeuP. If the response is insufficient after 2 - 4 weeks, the recommended next step is to switch to a different class, or combine different classes of agent. Opioids should be reserved for use later in the treatment pathway, if switching drugs and combination therapy fails. For central NeuP, pregabalin or amitriptyline are recommended as first-line agents. Companion treatments (cognitive behavioural therapy and physical therapy) should be administered as part of a multidisciplinary approach. Dorsal root entry zone rhizotomy (DREZ) is not recommended to treat NeuP. Given the large population of HIV/AIDS patients in South Africa, and the paucity of positive efficacy data for its management, research in the form of randomised controlled trials in painful HIV-associated sensory neuropathy (HIV-SN) must be prioritised in this country.

Pain in ambulatory HIV-positive South Africans.

We investigated the prevalence and intensity of pain, factors associated with having pain, and analgesic medications employed in a population consisting predominantly of Black African and female human immunodeficiency virus (HIV)-positive individuals attending outpatient clinics in a rural (n = 125; 79% female; 100% Black African) and a metropolitan (n = 396; 75% female; 94% Black African) area of South Africa. Pain intensity, interference and treatment were assessed using the Wisconsin Brief Pain Questionnaire. Seventy-two percent of rural participants and 56% of metropolitan participants had pain at the time of the interview, and this pain was moderate to severe in intensity in 60% of rural participants and 59% of metropolitan participants. Forty-six percent of rural participants and 61% of metropolitan participants had multiple pain sites. The most common pain sites in rural participants were the abdomen (30%), chest (26%), head (19%) and genitals (15%), while in the metropolitan cohort the head (39%), feet (33%), chest (30%) and abdomen (20%) were the most common sites. In the rural cohort, antiretroviral therapy was independently associated with reduced risk of pain, while in the metropolitan cohort increasing age was weakly, but independently associated with having pain. Pharmacological management of pain was poor, with 29% of rural participants and 55% of metropolitan participants with pain not receiving any treatment. Of those receiving treatment, no participants were receiving strong opioids, and only 3% of metropolitan participants were receiving a weak opioid. Thus, HIV-related pain is common and is poorly treated in both the rural and metropolitan setting in South Africa.

Hepatitis C seropositivity is not a risk factor for sensory neuropathy among patients with HIV.

BACKGROUND: Sensory neuropathy (SN) is common in patients with HIV. Hepatitis C (HCV) coinfection is often cited as an HIV-SN risk factor, but data to support this are lacking. This collaboration aimed to examine the association between HCV serostatus and SN risk among ambulatory HIV-positive patients. METHODS: Patients with HIV were assessed in cross-sectional studies in Baltimore, Jakarta, Johannesburg, Kuala Lumpur, Melbourne, and Sydney for SN (defined by both supportive symptoms and signs). HCV seropositivity was assessed as an SN risk using a chi(2) test, followed by logistic regression modeling to correct for treatment exposures and demographics. RESULTS: A total of 837 patients of African, Asian, and Caucasian descent were studied. HCV seroprevalence varied by site (Baltimore n = 104, 61% HCV+; Jakarta 96, 51%; Johannesburg 300, 1%; Kuala Lumpur 97, 10%; Melbourne 206, 16%; Sydney 34, 18%). HCV seropositivity was not associated with increased SN risk at any site, but was associated with reduced SN risk in Melbourne (p = 0.003). On multivariate analyses, the independent associations with SN were increasing age, height, and stavudine exposure. HCV seropositivity was not independently associated with an increased SN risk at any site, but associated independently with reduced SN risk in Baltimore (p = 0.04) and Melbourne (p = 0.06). CONCLUSIONS: Hepatitis C (HCV) seropositivity was not associated with increased sensory neuropathy risk among HIV-positive patients at any site. While we were unable to assess HCV RNA or liver damage, the data suggest that HCV coinfection is not a major contributor to HIV-SN. HCV = hepatitis C; SN = sensory neuropathy.

Effects of nitric oxide synthase inhibitors on the febrile response to muramyl dipeptide and lipopolysaccharide in rats.

We have administered aminoguanidine, a relatively specific inhibitor of inducible nitric oxide synthase, and N-nitro-L-arginine methyl ester (L-NAME), an unspecific nitric oxide synthase inhibitor, to rats made febrile with the gram-positive pyrogen, muramyl dipeptide and gram-negative pyrogen, lipopolysaccharide. Sprague-Dawley rats, housed individually at approximately 25 degrees C with a 12:12 h light:dark cycle (lights on 0700 hours), were injected (at 0900 hours) intraperitoneally with 50 mg/kg aminoguanidine, 25 mg/kg or 50 mg/kg L-NAME, and intramuscularly with 500 microg/kg muramyl dipeptide or 100 microg/kg lipopolysaccharide. Pyrogen injections were spaced at least 14 days apart. Body temperature was measured throughout the study in unrestrained animals using radio-telemetry. Neither muramyl dipeptide nor lipopolysaccharide-induced fevers were affected by aminoguanidine. However, L-NAME administration inhibited muramyl dipeptide and lipopolysaccharide-induced fevers, but only for the 1st 2-4 h of the fevers (two-way ANOVA, P<0.05). After the initial inhibition, lipopolysaccharide fevers developed normally. Therefore, constitutively expressed nitric oxide synthase appears to be involved in the initial phases of fever genesis of gram-negative and gram-positive fevers in rats. On the other hand, inducible nitric oxide synthase appears not to play a role in these fevers.

Miniature data loggers for remote measurement of body temperature in medium-sized rodents.

We have investigated the use of miniature temperature data loggers for the recording of abdominal temperature in laboratory animals, using the guinea pig as a model. The data loggers, which are small (16cm(3)), light (20g) and have a battery life of +/-5 years, recorded both the normal abdominal temperature of guinea pigs, and their febrile response to an intramuscular injection of 50µg/kg lipopolysaccharide (E. coli) every 5min for the duration of the experiment (21 days), to a resolution of at least 0.05 degrees C. No calibration shifts or loss of data occurred during the study period. However, despite their small size and versatility, we found that the loggers were suited for use only in guinea pigs with a body mass of approximately 600g or greater. In smaller animals, the loggers caused peritonitis.

Effects of nitric oxide synthase inhibitors on the febrile response to lipopolysaccharide and muramyl dipeptide in guinea pigs.

We investigated the effect of N-nitro-L-arginine methyl ester (L-NAME), an unspecific nitric oxide synthase (NOS) inhibitor, and aminoguanidine, a relatively selective inhibitor of the inducible NOS enzyme, on both gram-negative lipopolysaccharide (LPS) and gram-positive muramyl dipeptide (MDP) fever in guinea pigs. Intraperitoneal injection of either 10 mg/kg L-NAME or 25 mg/kg aminoguanidine inhibited the febrile response to an intramuscular injection of 50 microg/kg MDP. However, LPS fever (20 microg/kg) was inhibited only by L-NAME. The development of LPS fever may therefore occur independently of the synthesis of nitric oxide by the inducible NOS enzyme, while MDP fever may involve synthesis of nitric oxide by both the inducible and the constitutively expressed NOS enzymes.

Absence of selective brain cooling in free-ranging zebras in their natural habitat.

We used implanted miniature data loggers to measure brain and arterial blood temperatures in three free-ranging zebras (Equus burchelli) in their natural habitat, every 5 min for 9 days. The animals experienced globe temperatures exceeding 40 C, and radiant heat load of about 1000 W m-2. Arterial blood exhibited a moderate amplitude (1.7 C) nychthemeral rhythm, with an acrophase at 19.00 h and a nadir late in the morning, at 10.00 h. Brain temperature consistently exceeded blood temperature, on average by 0.2-0.4 C, and changes in brain temperature closely tracked changes in blood temperature. There was no evidence of selective brain cooling, even during the hyperthermia which followed surgery or that associated with intense, short-duration exercise. The relationship between brain and arterial blood temperatures in free-ranging zebras was unlike that reported for horses in the laboratory. Our results do not support the view that mammals lacking a carotid rete can achieve selective brain cooling.