Maternal cardiac output response to colloid preload and vasopressor therapy during spinal anaesthesia for caesarean section in patients with severe pre-eclampsia: a randomised, controlled trial.

We examined the haemodynamic effects of colloid preload, and phenylephrine and ephedrine administered for spinal hypotension, during caesarean section in 42 women with severe early onset pre-eclampsia. Twenty patients with pre-delivery spinal hypotension were randomly allocated to receive an initial dose of either 50 µg phenylephrine or 7.5 mg ephedrine; the primary outcome was percentage change in cardiac index. After a 300-ml colloid preload, mean (SD) cardiac index increased from 4.9 (1.1) to 5.6 (1.2) l.min-1 .m-2 (p < 0.01), resulting from an increase in both heart rate, from 81.3 (17.2) to 86.3 (16.5) beats.min-1 (p = 0.2), and stroke volume, from 111.8 (19.0) to 119.8 (17.9) ml (p = 0.049). Fourteen (33%) and 23 (54.8%) patients exhibited a stroke volume response > 10% and > 5%, respectively; a significant negative correlation was found between heart rate and stroke volume changes. Spinal hypotension in 20 patients was associated with an increase from baseline in cardiac index of 0.6 l.min-1 .m-2 (mean difference 11.5%; p < 0.0001). After a median [range] dose of 50 [50-150] µg phenylephrine or 15 [7.5-37.5] mg ephedrine, the percentage change in cardiac index during the measurement period of 150 s was greater, and negative, in patients receiving phenylephrine vs. ephedrine, at -12.0 (7.3)% vs. 2.6 (6.0)%, respectively (p = 0.0001). The percentage change in heart rate after vasopressor was higher in patients receiving phenylephrine, at -9.1 (3.4)% vs. 5.3 (12.6)% (p = 0.0027), as was the change in systemic vascular resistance, at 22.3 (7.5) vs. -1.9 (10.5)% (p < 0.0001). Phenylephrine effectively reverses spinal anaesthesia-induced haemodynamic changes in severe pre-eclampsia, if left ventricular systolic function is preserved.

Comparison between pulse waveform analysis and thermodilution cardiac output determination in patients with severe pre-eclampsia.

BACKGROUND: This study compared cardiac output (CO) measurements derived from pulse waveform analysis with values obtained by thermodilution (TD), in patients with post-partum complications of severe pre-eclampsia. METHODS: Eighteen patients were recruited, 24-96 h post-delivery. After central venous calibration of the pulse waveform analysis monitor (LiDCOplus), CO readings were compared with those obtained by the TD method and repeated twice at 15 min intervals. The comparison was repeated after peripheral venous calibration. Further comparisons were made in eight patients at 120 and 240 min after peripheral venous calibration. RESULTS: Data were pooled for measurements at 0, 15, and 30 min after calibration. For the comparison between TD and LiDCOplus using central venous calibration, TD exhibited a significant positive bias of 0.58 litre min⁻¹ [95% confidence interval (CI): 0.77 to 0.39]. After peripheral venous calibration, there was no significant bias [0.16 litre min⁻¹ (95% CI: -0.37 to 0.06)]. The estimated limits of agreement for central and peripheral venous calibrations were -2.12 to 0.96 and -1.50 to 1.20 litre min⁻¹, respectively. When comparing LiDCOplus and TD, there was no time-based effect at 120 or 240 min post-peripheral calibration. CONCLUSIONS: Central and peripheral venous calibrations of the LiDCOplus monitor were associated with clinically insignificant bias when compared with TD. Limits of agreement were within the recommendation of 30% for acceptance of a new CO technique when compared with current reference methods. This form of minimally invasive CO monitoring may have a valuable role in obstetric critical care.

Hypoxaemia during tracheal intubation in patients with hypertensive disorders of pregnancy: analysis of data from an obstetric airway management registry.

BACKGROUND: In South Africa, hypertensive disorders of pregnancy are the leading cause of maternal mortality. More than 50% of anaesthesia-related maternal deaths are attributed to complications of airway management. We compared the prevalence and risk factors for hypoxaemia during induction of general anaesthesia in parturients with and without hypertensive disorders of pregnancy. We hypothesised that hypertensive disorders of pregnancy are associated with desaturation during tracheal intubation. METHODS: Data from 402 cases in a multicentre obstetric airway management registry were analysed. The prevalence of peri-induction hypoxaemia (SpO2 <90%) was compared in patients with and without hypertensive disorders of pregnancy. Quantile regression of SpO2 nadir was performed to identify confounding variables associated with, and mediators of, hypoxaemia. RESULTS: In the cohort of 402 cases, hypoxaemia occurred in 19% with and 9% without hypertension (estimated risk difference, 10%; 95% CI 2% to 17%; P=0.005). Quantile regression demonstrated a lower SpO2 nadir associated with hypertensive disorders of pregnancy as body mass index increased. Room-air oxygen saturation, Mallampati grade, and number of intubation attempts were associated with the relationship. CONCLUSIONS: Clinically significant oxygen desaturation during airway management occurred twice as often in patients with hypertensive disorders of pregnancy, compounded by increasing body mass index. Intermediary factors in the pathway from hypertension to hypoxaemia were also identified.

A prospective clinical audit to evaluate postoperative quality of recovery in adults at New Somerset Hospital, Cape Town, South Africa.

BACKGROUND: Recent developments in perioperative medicine increasingly emphasise patient-centred approaches to quality of care metrics. To this end, the 15-item Quality of Recovery (QoR-15) scale is a well-validated and widely applied patient-centred measure of perioperative service quality. OBJECTIVES: To assess quality of recovery in a South African (SA) population by applying the QoR-15 and to identify the local contributors to poor quality of recovery. METHODS: A prospective observational study was performed in all adults undergoing elective and emergency surgery during daytime hours over a 2-week period in February 2019 at New Somerset Hospital, Cape Town, SA. Patients were approached by a qualitative interviewer on day 1 post surgery for consented recruitment, collection of demographic information and application of the QoR-15 questionnaire. RESULTS: Of 193 patients who had surgery, 154 fulfilled our criteria and completed the questionnaire. The median QoR-15 score was 123 out of 150, which is classified as 'good', although most patients (35%) fell into the 'moderate' category (90 - 121); 59% achieved the patient acceptable symptom state score (≥118). The median scores of the most poorly reported QoR-15 items were 5 for 'moderate pain' and 6 for 'able to return to work or usual home activities'. Poor scoring was not related to anaesthetic modality (p=0.088), surgical discipline (p=0.237), timing of surgery (p=0.717) or obstetric as opposed to non-obstetric patients (p=0.472). Construct validity was supported by a negative correlation with duration of anaesthesia (rho=-0.286; p<0.001) and lack of correlation with age (rho=-0.034; p=0.674). CONCLUSIONS: We found the QoR-15 to be a valid, feasible and acceptable tool for clinical auditing of perioperative service quality in SA. The median QoR-15 score was 123, with the majority of patients reflecting a moderate QoR. We have highlighted areas with potential for improvement and provided recommendations to address these aspects.

A randomised comparison of bolus phenylephrine and ephedrine for the management of spinal hypotension in patients with severe preeclampsia and fetal compromise.

BACKGROUND: Studies in healthy patients undergoing elective caesarean delivery show that, compared with phenylephrine, ephedrine used to treat spinal hypotension is associated with increased fetal acidosis. This has not been investigated prospectively in women with severe preeclampsia. METHODS: Patients with preeclampsia requiring caesarean delivery for a non-reassuring fetal heart tracing were randomised to receive either bolus ephedrine (7.5-15mg) or phenylephrine (50-100µg), to treat spinal hypotension. The primary outcome was umbilical arterial base excess. Secondary outcomes were umbilical arterial and venous pH and lactate concentration, venous base excess, and Apgar scores. RESULTS: Among 133 women, 64 who required vasopressor treatment were randomised into groups of 32 with similar patient characteristics. Pre-delivery blood pressure changes were similar. There was no difference in mean [standard deviation] umbilical artery base excess (-4.9 [3.7] vs -6.0 [4.6] mmol/L for ephedrine and phenylephrine respectively; P=0.29). Mean umbilical arterial and venous pH and lactate concentrations did not significantly differ between groups (7.25 [0.08] vs 7.22 [0.10], 7.28 [0.07] vs 7.27 [0.10], and 3.41 [2.18] vs 3.28 [2.44] mmol/L respectively). Umbilical venous oxygen tension was higher in the ephedrine group (2.8 [0.7] vs 2.4 [0.62]) kPa, P=0.02). There was no difference in 1- or 5-min Apgar scores, numbers of neonates with 1-min Apgar scores <7 or with a pH <7.2. CONCLUSIONS: In patients with severe preeclampsia and fetal compromise, fetal acid-base status is independent of the use of bolus ephedrine versus phenylephrine to treat spinal hypotension.

Mechanical tracheal obstruction due to an intramural esophageal hematoma following endoscopic variceal sclerotherapy.

Endoscopic injection sclerotherapy is widely used as treatment for bleeding esophageal varices. Esophageal intramural hematoma is a rare complication following endoscopic injection sclerotherapy. Patients present with pain and dysphagia due to esophageal obstruction. We present the first reported case of respiratory failure resulting from an intramural hematoma causing posterior tracheobronchial compression. Although patients with alcoholic cirrhosis and bleeding varices requiring respiratory support generally have a poor prognosis this may be an occasion when ventilatory support may be expected to be easily withdrawn after hematoma resolution.

Surgery and anaesthesia in art: the contribution of Dorothy Kay.

Dorothy Kay, the acclaimed Irish-born Port Elizabeth artist, married Dr Hobart Kay, FRCSI, in Cape Town, South Africa, in 1910. She was an exceptional portrait painter, whose astute observation of detail and ability to empathise with her subject and convey character brought her much important work. Her traditional British realist-school style of painting, and ability to depict mechanical equipment accurately, led to several industrial commissions. In 1937 these skills combined to produce her largest painting, 'Surgery' which depicts a patient undergoing an abdominal operation in a Port Elizabeth hospital. The painting graphically captures the skill and care exhibited by the anaesthetist, together with the anaesthetic equipment used at that time. During the war Dorothy became an accredited war artist. Eight of her wartime paintings were purchased by the Union Government and are now housed in the Ditsong National Museum of Military History in Saxonwold, Johannesburg. Two of these paintings of medical interest are discussed. The first, entitled 'Operation in a Base Hospital, depicts surgery being performed in a base hospital and is very similar in composition to 'Surgery' The second, entitled 'Blood to Save Lives, portrays a volunteer donating blood.

New and known diketopiperazines from the Caribbean sponge, Calyx cf. podatypa.

The cyanobacteria-containing Caribbean sponge, Calyx cf. podatypa, was collected from three sites in the Bahamas. In each of the three collections, a polar solvent partition fraction contained six known compounds including five diketopiperazines [1-4,6] and phenylacetic acid, along with a new diketopiperazine, cyclo-(4-methyl-R-proline-S-norvaline) [5]. Interestingly, all six diketopiperazines are proline-derived cyclic dipeptides. This is the first example for this class of peptide derivative to be isolated from a Calyx sponge. Parallel studies of one of the sponge collections in which the ectosome (cyanobacteria-rich) was separated from the endosome (no cyanobacteria) revealed no significant differences in their content of diketopiperazines.