Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2010
Review Comparative StudyHeparin dose response is independent of preoperative antithrombin activity in patients undergoing coronary artery bypass graft surgery using low heparin concentrations.
Unfractionated heparin's primary mechanism of action is to enhance the enzymatic activity of antithrombin (AT). We hypothesized that there would be a direct association between preoperative AT activity and both heparin dose response (HDR) and heparin sensitivity index (HSI) in patients undergoing coronary artery bypass graft surgery. ⋯ Although enhancing AT activity is the primary mechanism by which heparin facilitates cardiopulmonary bypass anticoagulation, low preoperative AT activity is not associated with impaired response to heparin or to clinical outcomes when using target ACTs of 300 to 350 seconds.
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Anesthesia and analgesia · Oct 2010
Review Comparative StudyHeated humidification versus heat and moisture exchangers for ventilated adults and children.
Humidification by artificial means must be provided when the upper airway is bypassed during mechanical ventilation. Heated humidification (HH) and heat and moisture exchangers (HMEs) are the most commonly used types of artificial humidification in this situation. ⋯ There is little evidence of an overall difference between HMEs and HHs. However, hydrophobic HMEs may reduce the risk of pneumonia and the use of an HMEs may increase artificial airway occlusion in certain subgroups of patients. Therefore, HMEs may not be suitable for patients with limited respiratory reserve or prone to airway blockage. Further research is needed relating to hydrophobic versus hygroscopic HMEs and the use of HMEs in the pediatric and neonatal populations. As the design of HMEs evolves, evaluation of new generation HMEs will also need to be undertaken.
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Anesthesia and analgesia · Oct 2010
Review Comparative StudyInfraclavicular brachial plexus block for regional anaesthesia of the lower arm.
Several approaches exist to produce local anaesthetic blockade of the brachial plexus. It is not clear which is the technique of choice for providing surgical anaesthesia of the lower arm although infraclavicular blockade (ICB) has several purported advantages. We therefore performed a systematic review of ICB compared to the other brachial plexus blocks (BPBs). ⋯ ICB is a safe and simple technique for providing surgical anaesthesia of the lower arm, with an efficacy comparable to other BPBs. The advantages of ICB include a lower likelihood of tourniquet pain during surgery, and more reliable blockade of the musculocutaneous and axillary nerves when compared to a single-injection axillary block. The efficacy of ICB is likely to be improved if adequate time is allowed for block onset (at least 30 minutes) and if a volume of at least 40 ml is injected. Since publication of many of the trials included in this review, it has become clear that a distal posterior cord motor response is the appropriate endpoint for electrostimulation-guided ICB; we recommend it be used in all future comparative studies. There is also a need for additional RCTs comparing ultrasound-guided ICB with other BPBs.
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Anesthesia and analgesia · Oct 2010
Review Case ReportsCase report: epidural hematoma nine days after removal of a labor epidural catheter.
Timely recognition and surgical decompression are crucial to minimize risk of permanent neurologic deficit from epidural hematoma. We present the case of a patient who developed acute back pain, sensory deficit, and ascending weakness 9 days after removal of a labor epidural catheter. Magnetic resonance imaging revealed a heterogeneous fluid collection extending from C6-7 through the lumbar region, with cord deformity at T9-11. ⋯ Twelve hours later, her motor function had fully recovered. Subsequent anatomic and hematologic workup was inconclusive. This presentation is atypical given the delayed presentation of symptoms after epidural placement.
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Anesthesia and analgesia · Oct 2010
Review Case ReportsSymptomatic axillary hematoma after ultrasound-guided infraclavicular block in a patient with undiagnosed upper extremity mycotic aneurysms.
We present a case of axillary hematoma complicating an ultrasound-guided infraclavicular block in a patient with undiagnosed mycotic aneurysms of the peripheral arteries. Mycotic aneurysm is a rare medical condition with well-identified risk factors. When performing regional anesthesia in patients with these risk factors, clinicians should have a high degree of suspicion about the possible existence of vascular anomalies. A preprocedure Doppler study of the block area and real-time guidance of the needle using ultrasound may be useful.