Anaesthesia
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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.
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This prospective observational study investigated the effect of focused transthoracic echocardiography in 99 patients who had suspected cardiac disease or were ≥ 65 years old, and were scheduled for emergency non-cardiac surgery. The treating anaesthetist completed a diagnosis and management plan before and after transthoracic echocardiography, which was performed by an independent operator. Clinical examination rated cardiac disease present in 75%; the remainder were asymptomatic. ⋯ Cardiac disease was identified by echocardiography in 64% of patients, which led to a step-up of treatment in 36% (4% delay for cardiology referral, 2% altered surgery, 4% intensive care and 26% intra-operative haemodynamic management changes). Absence of cardiac disease in 36% resulted in a step-down of treatment in 8% (no referral 3%, intensive care 1% or haemodynamic treatment 4%). Pre-operative focused transthoracic echocardiography in patients admitted for emergency surgery and with known cardiac disease or suspected to be at risk of cardiac disease frequently alters diagnosis and management.
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Randomized Controlled Trial Comparative Study
Comparison of Macintosh and Airtraq™ laryngoscopes in obese patients placed in the ramped position.
This study compared intubation conditions produced by the Macintosh and Airtraq™ laryngoscopes when used in obese patients in the ramped position. One hundred and thirty-two patients having bariatric surgery were placed in the ramped position and randomly assigned to have their tracheas intubated using either the Macintosh (n=64) or an Airtraq (n=68) laryngoscope. ⋯ One patient in the Macintosh group had a failed intubation and intubation was achieved with the Airtraq. For obese patients in ramped position, Airtraq affords faster tracheal intubation than the Macintosh laryngoscope.
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Postoperative cognitive dysfunction is receiving increasing attention, particularly as it mainly affects the (growing) elderly population. Until recently, cognitive deficits after cardiac surgery were thought to be caused by physiological disturbances associated with the cardiopulmonary bypass technique. ⋯ Priming of the immune system by ageing and atherosclerosis may result in an exaggerated systemic and cerebral inflammatory response to cardiac surgery and anaesthesia, causing neuronal loss or dysfunction resulting in cognitive dysfunction. We briefly discuss the evidence for cardiopulmonary bypass-related neuronal injuries in adult cardiac surgery patients, and review the evidence that immune priming is a key factor in the pathogenesis of cognitive dysfunction after cardiac surgery.
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Comparative Study
Clinical evaluation of a new tracheal impedance cardiography method.
Non-invasive cardiac output measurement by means of impedance cardiography has been evaluated before, and agreement with other methods has been variable. We decided to study a newly developed tracheal impedance device, that is claimed to be more accurate and reliable. This incorporates new software and mathematical formulae, that are designed to reduce signal noise from diathermy, leading to improved accuracy. ⋯ Mean cardiac output, bias and 95% limits of agreement were 5.3, 0.03 and -2.8 to 2.8 l.min(-1) , respectively. Tracheal impedance showed good correlation with measurement trends using thermodilution in 88% of measurements, with a mean (95% limit of agreement) angular bias of -9.0° (-83.3 to 65.3°). However, the wide limits of agreement and high percentage error of 53% that were apparent in this study mean that, in its present guise, tracheal impedance is not an acceptable alternative to thermodilution in cardiac surgical patients.