Page 663 - ACCCN's Critical Care Nursing

640 S P E C I A LT Y P R A C T I C E I N C R I T I C A L C A R E

perforation has occurred, such as bruising across the area assessment and measurement techniques that exist, but
of the abdominal seatbelt, small bowel perforation may has been reported to be between 1% and 33%. 65
be present. These patients are characterised by pain out High IAP can have effects on multiple systems through-
of proportion to that expected with superficial abdominal out the body, as follows: 65,66
wall contusions. Other signs of abdominal trauma can be
related to the structure that has been injured. For example, l gut and hepatic effects: reduced blood flow to abdom-
haematuria demonstrates trauma to some part of the inal organs
urinary tract, including the kidneys. l renal effects: reduced renal blood flow and glomerular
filtration rate
Description l cardiovascular effects: decreased venous return through
The abdomen is susceptible to injury from a variety of pressure on the inferior vena cava and raised intratho-
external causes, both blunt and penetrating (see discus- racic pressure, leading to reduced cardiac output
sion of penetrating injuries below). A key aspect to l respiratory effects: where pressure on the abdominal
remember with any abdominal injury is that the superfi- side of the diaphragm increases abdominal resistance
cial injury does not always reflect what lies below. For to inspiration. In ventilated patients this is usually
example, it is not possible to be certain of the trajectory demonstrated by elevated peak inspiratory pressures,
that a bullet took after it passed through the skin. resulting in reducing tidal volume and minute volume
as the ventilator cycles off when either the preset pres-
Contusion/laceration sure is reached or pressure alarms are triggered
l central nervous system effects: reduced cerebral blood
Sudden deceleration of moving body tissues can result in flow due to the raised intracranial pressure from
laceration or haemorrhage into the tissues (contusion). impaired venous drainage. When this is coupled with
This is related to the tearing of the tissues that occurs due a lower cerebral perfusion pressure that results from
to inertia, or the tendency of tissues to resist changes in the reduced cardiac output, it is deleterious to the
speed or direction (e.g. to keep moving forwards when injured brain
the body has stopped moving, resulting in a tearing l cytokine response: activation of the stress response,
action to the tissues). Any structure in the abdomen is seen through raised interleukins IL-6 and IL-1 alpha,
susceptible to this type of injury. Commonly, the liver as well as tumour necrosis factor.
and spleen are the worst-affected organs, largely related
to a seatbelt injury in motor vehicle collisions. Laceration A high level of suspicion for ACS should be retained for
of a solid organ can be a minor injury that is appropri- all patients with abdominal trauma as well as those who
ately monitored and managed conservatively; alterna- have had abdominal surgery for other reasons. Clinical
tively, a similar injury can lead to exsanguination (e.g. a examination, looking for a distended and firm abdomen,
liver laceration into the hilum that involves the inferior is insensitive in the early stages of ACS; however, these
vena cava). Hollow viscus can be contused, as can the signs should be identified if ACS progresses to a late state.
mesentery and peritoneum. Proactive detection of ACS is more effectively carried out
through the use of routine IAP measurements in all
Perforation patients who have the potential to develop ACS. While
agreement as to the precise levels of IAP that indicate ACS
Full-thickness injury, or perforation, to a hollow viscus is yet to be achieved, there is widespread agreement that
organ is life-threatening. Perforation of the intestine can values above approximately 20 mmHg require investiga-
result in peritoneal soiling and ischaemic bowel. Small tion; and pressures above 25 mmHg, in association with
bowel injuries are particularly difficult to diagnose; if other clinically relevant findings such as firm or distended
diagnosis is delayed, morbidity can be severe. The abdom- abdomen and the systemic effects outlined above, often
inal seatbelt sign – in other words, bruising across the indicate a need for urgent surgery. 65,66
anterior abdominal wall that follows the path of the lap
and sash of the seatbelt – is a sentinel sign for hollow IAP can be measured directly by laparoscopy, but is more
64
viscus perforation. Importantly, patients with this type effectively measured on an ongoing basis, either intermit-
of abdominal trauma can present late (by days). If pre- tently or continuously, via an indirect technique of mea-
senting late, the usual clinical manifestations are pain, suring bladder pressures. IAP measurements are achieved
peritonitis and sepsis. 64 using an indwelling urinary catheter with a pressure
transducer or manometer levelled to the midaxillary line
Secondary injury: abdominal compartment and attached via a T piece to allow continuous sterile
67
syndrome (ACS) access. According to the World Society of the Abdomi-
The abdominal viscera are highly vascular and subject to nal Compartment Syndrome Guidelines, intermittent
67
measurements are obtained as follows:
vascular engorgement during massive fluid resuscitation.
Where this occurs, there is an acute rise in intra-abdominal 1. Lay the patient flat, or head-up if undergoing head
pressure (IAP). In severe cases, the IAP will rise to the injury management. If the IAP is measured with
point where cardiorespiratory function is compromised. the patient head-up, the level of elevation should
This is a surgical emergency and the abdominal cavity be documented to ensure that future measure-
requires decompression immediately. The incidence of ments are done with the patient in the same
ACS is difficult to determine because of the different position.