British journal of anaesthesia
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Since the performance of the first thoracic spinal anaesthetic in early 1908 many anaesthetists have gained interest in this unorthodox neuraxial anaesthetic technique. The main rationale justifying its use is to prevent complications related to general anaesthesia in high-risk patient populations. ⋯ The main concerns are fear of iatrogenic injury to the spinal cord, cephalad spread of local anaesthetic causing a complete spinal block, and haemodynamic instability owing to blockade of cardioaccelerator sympathetic fibres. The purpose of this narrative review is to appraise the literature critically regarding thoracic spinal anaesthesia, to synthesise the available information, and to provide a summary of evidence justifying its use in modern anaesthesia.
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Although thoracic surgery is understood to confer a high risk of postoperative respiratory complications, the substantial haemodynamic challenges posed are less well appreciated. This review highlights the influence of cardiovascular comorbidity on outcome, reviews the complex pathophysiological changes inherent in one-lung ventilation and lung resection, and examines their influence on cardiovascular complications and postoperative functional limitation. There is now good evidence for the presence of right ventricular dysfunction postoperatively, a finding that persists to at least 3 months. ⋯ Postoperative right ventricular dysfunction has been implicated in the aetiology of postoperative atrial fibrillation and perioperative myocardial injury, both common cardiovascular complications which are increasingly being appreciated to have impact long into the postoperative period. In response to the physiological demands of critical illness or exercise, contractile reserve, flow reserve, or both can be overwhelmed resulting in acute decompensation or impaired long-term functional capacity. Aiding adaptation to the unique perioperative physiology seen in patients undergoing thoracic surgery could provide a novel therapeutic avenue to prevent cardiovascular complications and improve long-term functional capacity after surgery.
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Recent reports highlight potential inaccuracies of pulse oximetry in patients with various degrees of skin pigmentation. We summarise the literature, provide an overview of potential clinical implications, and provide insights into how pulse oximetry could be improved to mitigate against such potential shortcomings.
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Myocardial injury is now an acknowledged complication in patients undergoing noncardiac surgery. Heterogeneity in the definitions of myocardial injury contributes to difficulty in evaluating the value of cardiac troponins (cTns) measurement in perioperative care. Pre-, post-, and peri-operatively increased cTns are encompassed by the umbrella term 'myocardial injury' and are likely to reflect different pathophysiological mechanisms. ⋯ Preoperative measurement of cTns aids preoperative risk stratification beyond the Revised Cardiac Risk Index. Systematic measurement detects acute perioperative increases and allows early identification of acute myocardial injury. Common definitions and standards for reporting are a prerequisite for designing impactful future trials and perioperative management strategies.
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Patient-ventilator asynchrony during mechanical ventilation may exacerbate lung and diaphragm injury in spontaneously breathing subjects. We investigated whether subject-ventilator asynchrony increases lung or diaphragmatic injury in a porcine model of acute respiratory distress syndrome (ARDS). ⋯ Subject-ventilator asynchrony during spontaneous breathing did not exacerbate lung injury and dysfunction in experimental porcine ARDS.