Emerging concepts and techniques Permissive hypotension
Also called hypotensive resuscitation, this concept is of increasing interest to trauma surgeons faced with intra-abdominal or intrathoracic haemorrhage. The important question is whether the systolic blood pressure needs to be returned to premorbid levels utilising fluid resuscitation. In nontrauma patients, vascular patients for example, controlled preoperative hypotension is well established in certain situations. Further, recent research in the USA seems to deprecate the use of rapid infusion systems (RIS), with evidence emerging that large volume fluid resuscitation to achieve normal systolic blood pressures is associated with increased mortality compared with injured patients resuscitated with small fluid volumes prior to surgery. An increasingly accepted view holds that moderate hypotension — systolic blood pressure of 85—90 mmHg — is sufficient to maintain vital organ perfusion and avoids a hypertensive overshoot with the risk of precipitating further haemorrhage. The concept is still new in the care of the injured and further trials on optimal fluids, levels of permissive hypotension and the effects of delay before surgery are needed before it can be safely assimilated. The most important message to retain is that the best treatment for ongoing haemorrhage is to turn off the tap and not to continue infusion of fluids, including blood products.
Damage control — staged or abbreviated laparotomy
The concept of staged operative procedures for the severely injured patient is not new. The earliest uses of the approach concerned perihepatic packing for extensive liver injury. While the commonest indication remains catastrophic intraabdominal haemorrhage, the technique now has wider application. The technique should usually be considered as part of the primary survey and resuscitation phases in patients who fail to respond to nonoperative resuscitation methods. The technical aspects of the procedure are dictated by the pattern of injuries. The objectives are listed below.
Objectives of staged or abbreviated laparotomy
• Arrest haemorrhage
• Control or limit coagulopathy
• Limit cavity contamination
• Protect viscera and limit fluid/protein loss
Having achieved the objectives, the patient is returned to a critical care environment for continuing monitoring, resuscitation and in-depth investigation prior to a second definitive procedure. Moore terms this ‘physiological restoration in a surgical intensive care unit’. Timing for the definitive procedure varies but is usually within 24 hours of the damage-control procedure.
Focused abdominal sonogram for trauma (FAST)
Portable, hand-held ultrasound is now being used by trauma surgeons in the USA in the evaluation of patients with blunt thoracoabdominal trauma, and is the preferred initial technological assessment of the patient. It belongs early on in the secondary survey, although some centres advocate its use during the ‘C’ component of the primary survey to localise intra-abdominal haemorrhage and to rule out cardiac tamponade in overtly shocked patients where no haemorrhage source is evident. The technique is rapid, with only four areas being scanned at the initial investigation. One of the greatest challenges will be to train trauma surgeons in the use of the technology.
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