A.T. Dennis

Acute pulmonary oedema in pregnant women.

Acute pulmonary oedema in pregnant women is an uncommon but life‐threatening event. The aims of this review are to address why pulmonary oedema occurs in pregnant women and to discuss immediate management. We performed a systematic literature search of electronic databases including MEDLINE, EMBASE and the Cochrane Library, using the key words obstetrics, pregnancy, acute pulmonary oedema, pregnancy complications, maternal, cardiac function and haemodynamics. We present a simple clinical classification of acute pulmonary oedema in pregnancy into pulmonary oedema occurring in normotensive or hypotensive women (i.e. without hypertension), and acute pulmonary oedema occurring in hypertensive women, which allows focused management. Pre‐eclampsia remains an important cause of hypertensive acute pulmonary oedema in pregnancy and preventive strategies include close clinical monitoring and restricted fluid administration. Immediate management of acute pulmonary oedema includes oxygenation, ventilation and circulation control with venodilators. Pregnancy‐specific issues include consideration of the physiological changes of pregnancy, the risk of aspiration and difficult airway, reduced respiratory and metabolic reserve, avoidance of aortocaval compression and delivery of the fetus.

Transthoracic echocardiography in obstetric anaesthesia and obstetric critical illness

Transthoracic echocardiography (TTE) is a powerful non-invasive diagnostic, monitoring and measurement device in medicine. In addition to cardiologists, many other specialised groups, including emergency and critical care physicians and cardiac anaesthetists, have recognised its ability to provide high quality information and utilise TTE in the care of their patients. In obstetric anaesthesia and management of obstetric critical illness, the favourable characteristics of pregnant women facilitate TTE examination. These include anterior and left lateral displacement of the heart, frequent employment of the left lateral tilted position to avoid aortocaval compression, spontaneous ventilation and wide acceptance of ultrasound technology by women. Of relevance to obstetric anaesthetists is that maternal morbidity and mortality due to cardiovascular disease is significant worldwide. This makes TTE an appropriate, important and applicable device in pregnant women. Clinician-performed TTE enables differentiation between the life-threatening causes of hypotension. In the critically ill woman this improves diagnostic accuracy and allows treatment interventions to be instituted and monitored at the point of patient care. This article outlines the application of TTE in the specialty of obstetric anaesthesia and in the management of obstetric critical illness. It describes the importance of TTE education, quality assurance and outcome recording. It also discusses how barriers to the routine implementation of TTE in obstetric anaesthesia and management of obstetric critical illness can be overcome.

Management of pre-eclampsia: issues for anaesthetists

Pre‐eclampsia is a leading cause of maternal morbidity and mortality. Substandard care is often present and many deaths are preventable. The aim of this review is to summarise the key management issues for anaesthetists in the light of the current literature. A systematic literature search of electronic databases was undertaken including MEDLINE, EMBASE and the Cochrane Library using the key words obstetrics, pregnancy, pregnancy complications, maternal, pre‐eclampsia, preeclampsia, cardiac function, haemodynamics, haemolysis, elevated liver enzymes, low platelets (HELLP), eclampsia, anaesthesia, anesthesia, neuraxial. Relevant Colleges and Societies websites were examined for pertinent guidelines. The disease is defined within the context of hypertensive diseases, and early recognition of pre‐eclampsia and its complications, as well as multidisciplinary expert team management is highlighted. Accurate monitoring and recording of observations including the use of transthoracic echocardiography is discussed. The importance of the treatment of systolic blood pressure > 180 mmHg and the use of intravenous antihypertensive medication as well as the use of parenteral magnesium sulphate for the treatment and prevention of eclampsia is emphasised . Restricted intravenous fluid therapy and avoidance of ergometrine is discussed. Neuraxial analgesia and anaesthesia, and general anaesthesia for birth is summarised as well as postpartum management including analgesia, thromboprophylaxis, management of acute pulmonary oedema and the use of pharmacological agents in the setting of breastfeeding.

Haemodynamics in women with untreated pre-eclampsia.

This study aimed to compare the haemodynamics in healthy pregnant women with the haemodynamics in women with untreated pre‐eclampsia, to determine the cardiovascular reason for hypertension in pre‐eclampsia. 40 women with untreated pre‐eclampsia, 40 matched healthy pregnant women and 20 non‐pregnant women were studied using transthoracic echocardiography. Untreated pre‐eclampsia demonstrated (mean (SD), healthy non‐pregnant vs healthy pregnant vs untreated pre‐eclampsia) increased cardiac output (3400 (752) vs 4109 (595) vs 4789 (1416) ml.min−1, p = 0.002), increased stroke volume (53 (10) vs 53 (8) vs 59 (13) ml, p = 0.04), increased fractional shortening (35 (5) vs 35 (7) vs 41 (8) %, p = 0.006), increased fractional area change (57 (7) vs 57 (9) vs 65 (9) %, p = 0.002) and increased systemic vascular resistance (2116 (457) vs 1613 (315) vs 2016 (625) dyne.s.cm−5, p = 0.001). Mitral E/septal e′ was higher (6.0 (1.1) vs 6.7 (1.3) vs 10.4 (2.4), p = 0.002) and left atrial size increased (3.2 (0.3) vs 3.8 (0.4) vs 4.0 (0.4) cm, p = 0.002). Hypertension in untreated pre‐eclampsia is due to increased cardiac output and mild vasoconstriction, with increased inotropy and reduced diastolic function.

Minimal Clinically Important Difference for Three Quality of Recovery Scales.

Background:Several quality of recovery (QoR) health status scales have been developed to quantify the patient’s experience after anesthesia and surgery, but to date, it is unclear what constitutes the minimal clinically important difference (MCID). That is, what minimal change in score would indicate a meaningful change in a patient’s health status? Methods:The authors enrolled a sequential, unselected cohort of patients recovering from surgery and used three QoR scales (the 9-item QoR score, the 15-item QoR-15, and the 40-item QoR-40) to quantify a patient’s recovery after surgery and anesthesia. The authors compared changes in patient QoR scores with a global rating of change questionnaire using an anchor-based method and three distribution-based methods (0.3 SD, standard error of the measurement, and 5% range). The authors then averaged the change estimates to determine the MCID for each QoR scale. Results:The authors enrolled 204 patients at the first postoperative visit, and 199 were available for a second interview; a further 24 patients were available at the third interview. The QoR scores improved significantly between the first two interviews. Triangulation of distribution- and anchor-based methods results in an MCID of 0.92, 8.0, and 6.3 for the QoR score, QoR-15, and QoR-40, respectively. Conclusion:Perioperative interventions that result in a change of 0.9 for the QoR score, 8.0 for the QoR-15, or 6.3 for the QoR-40 signify a clinically important improvement or deterioration.

Ability of non-invasive intermittent blood pressure monitoring and a continuous non-invasive arterial pressure monitor (CNAP™) to provide new readings in each 1-min interval during elective caesarean section under spinal anaesthesia.

We compared the ability of automated non‐invasive intermittent oscillometric blood pressure monitoring with a new device, CNAPTM (continuous non‐invasive arterial pressure) to provide a new blood pressure reading in each 1‐min interval between spinal anaesthesia and delivery during caesarean section. We also compared the accuracy of continuous non‐invasive arterial pressure readings with non‐invasive blood pressure measurements before spinal anaesthesia. Fifty‐nine women participated. The non‐invasive and continuous non‐invasive monitors displayed new blood pressure readings in a mean of 82% (11%) and 83% (13%) (p = 0.97) of the one‐minute intervals between spinal anaesthesia and delivery, respectively. Continuous non‐invasive arterial pressure was more likely to fail on two or more consecutive minutes (p = 0.001). From the pre‐spinal readings, the mean bias, defined as non‐invasive – continuous non‐invasive arterial pressure, and limits of agreement (±2SD mean bias) for systolic, diastolic and mean blood pressure respectively were +1.3 (±26.0), −2.9 (±21.8) and +2.6 (±20.4) mmHg. The new monitor has disadvantages compared with conventional non‐invasive intermittent blood pressure monitoring.

Prospective observational study of serial cardiac output by transthoracic echocardiography in healthy pregnant women undergoing elective caesarean delivery

BACKGROUND An understanding of cardiovascular changes in parturients is crucial for their anaesthetic management, but few studies have examined the effect of posture on cardiac output in the peripartum period. METHOD Cardiac output was measured in four different positions by transthoracic echocardiography (Doppler) in 30 term women undergoing elective caesarean delivery. These positions were left lateral level (P1), left lateral with 20 degrees head up (P2), left lateral with 10 degrees head down (P3) measured preoperatively and supine (P4) measured postoperatively. RESULTS Mean +/- SD cardiac output was 4407+/-1109 mL/min (P1), 4182+/-825 mL/min (P2), 4031+/-798 mL/min (P3) and 4641+/-1064 mL/min (P4). Cardiac output was significantly less in P3 than in P1 (P = 0.049) due to a lower P3 velocity time integral compared with P1 (P = 0.020). Postoperatively, in the supine position, there was no difference in cardiac output, although there was a lower heart rate (P = <0.001) and increased velocity time integral (P = <0.001) compared with P1. The mean differences in interobserver measurements were 0.02 cm (left ventricular outflow tract) and -1.06 cm (velocity time integral). The mean differences in intraobserver measurements were 0.00 cm (left ventricular outflow tract) and -0.22 cm (velocity time integral). Echocardiography was well accepted by all women. Eight women found the left lateral 10 degrees head-down position (P3) uncomfortable due to dizziness, headache, or increased abdominal pressure. CONCLUSIONS Cardiac output showed large variability and was lower than previously reported. Cardiac output decreased with the left lateral 10 degrees head-down position due to a reduction in stroke volume that has not previously been reported. The transthoracic examination was acceptable to all women.

Echocardiographic differences between preeclampsia and peripartum cardiomyopathy.

Peripartum heart failure due to preeclampsia or peripartum cardiomyopathy represents a significant global health issue. Transthoracic echocardiography enables differentiation of heart failure with preserved ejection fraction, commonly observed in women with preeclampsia, from that with peripartum cardiomyopathy in which a reduced ejection fraction is more common. An understanding of the different definitions and diagnostic features of these two diseases, as well as accurate characterisation of the haemodynamics in preeclampsia and peripartum cardiomyopathy, allows clinicians to manage these conditions appropriately. This article outlines the echocardiographic differences between preeclampsia and peripartum cardiomyopathy, the likely mechanisms for heart failure in preeclampsia and the relevance of these differences to clinicians in relation to prevention and treatment. It also emphasises the importance of disease definitions as a key framework for the more consistent classification of the two diseases.

Measuring acute postoperative pain using the visual analog scale: the minimal clinically important difference and patient acceptable symptom state

Background The 100 mm visual analog scale (VAS) score is widely used to measure pain intensity after surgery. Despite this widespread use, it is unclear what constitutes the minimal clinically important difference (MCID); that is, what minimal change in score would indicate a meaningful change in a patients pain status. Methods We enrolled a sequential, unselected cohort of patients recovering from surgery and used a VAS to quantify pain intensity. We compared changes in the VAS with a global rating-of-change questionnaire using an anchor-based method and three distribution-based methods (0.3 sd , standard error of the measurement, and 5% range). We then averaged the change estimates to determine the MCID for the pain VAS. The patient acceptable symptom state (PASS) was defined as the 25th centile of the VAS corresponding to a positive patient response to having made a good recovery from surgery. Results We enrolled 224 patients at the first postoperative visit, and 219 of these were available for a second interview. The VAS scores improved significantly between the first two interviews. Triangulation of distribution and anchor-based methods resulted in an MCID of 9.9 for the pain VAS, and a PASS of 33. Conclusions Analgesic interventions that provide a change of 10 for the 100 mm pain VAS signify a clinically important improvement or deterioration, and a VAS of 33 or less signifies acceptable pain control (i.e. a responder), after surgery.

Transthoracic echocardiography in women with preeclampsia.

Purpose of review Recent literature on the role of transthoracic echocardiography in the management of women with preeclampsia is reviewed with emphasis on recommendations for its use in the life-threatening complications of acute pulmonary edema, chest pain, and hemorrhage. Recent findings The diagnostic criteria for preeclampsia are closer to reaching international consensus with most guidelines now removing the mandatory requirement for proteinuria. Hemodynamic findings using transthoracic echocardiography in women with untreated preeclampsia include normal or increased cardiac output, normal or increased contractility, a nondilated left ventricle, diastolic dysfunction, increased pericardial effusions, and increased left ventricular mass. Echocardiography is recommended as a diagnostic and monitoring tool for acute hemodynamic complications of preeclampsia, such as acute pulmonary edema, significant arterial hypertension, and chest pain. Despite this there has been limited uptake of transthoracic electrocardiography into routine clinical practice in women with preeclampsia. Summary The role of transthoracic echocardiography in the management of women with preeclampsia is emphasized by international groups. Research into the hemodynamics in preeclampsia, which demonstrates preserved ejection fraction, and diastolic dysfunction highlights its utility and acceptability by pregnant women with preeclampsia. Training of obstetric anesthesiologists in echocardiography is necessary to enable more widespread implementation of this important technology.