Page 275 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 27: Intravascular Devices in the ICU 179

period of hypothermia? Would certain drugs serve as useful adjuncts to • Maze R, Le May MR, Hibbert B, et al. The impact of therapeutic
hypothermia, either to provide additional benefit or to protect against hypothermia as adjunctive therapy in a regional primary PCI
certain adverse effects of a cooled state? A number of pharmacologic program. Resuscitation. 2013;84(4):460-464.doi: 10.1016/j.resus-
strategies have been employed to protect against IR injury, includ- citation.2012.08.002.
ing barbiturates, benzodiazepines, and gas anesthetic agents. These
and other issues surrounding induced hypothermia await randomized • Nielsen N, Wetterslev J, Cronberg T, et al. Targeted temperature
clinical trials. management at 33 degrees C versus 36 degrees C after cardiac
arrest. N Engl J Med. 2013;369(23):2197-206.
FUTURE OF INDUCED HYPOTHERMIA • Peberdy MA, Callaway CW, Neumar RW, et al. Part 9: Post–Cardiac
Arrest Care: 2010 American Heart Association Guidelines for
Before induced hypothermia becomes a standard therapy for such criti- Cardiopulmonary Resuscitation and Emergency Cardiovascular
cal illnesses as myocardial infarction, stroke, and cardiac arrest, many of Care. Circulation. 2010;122:S768-S786.
the questions just posed will require resolution. It is also important to • Rosomoff HL, Holaday DA. Cerebral blood flow and cerebral oxy-
note that the optimal combination of these factors may be different for gen consumption during hypothermia. Am J Physiol. 1954;179:85.
each disease state, and therefore, such principles may not be generalized
easily. It is possible, for example, that adverse effects such as electrolyte • Shiozaki T, Hayakata T, Taneda M, et al. A multicenter prospective
abnormalities may limit the depth of cooling in the more critically ill randomized controlled trial of the efficacy of mild hypothermia
state of resuscitated cardiac arrest compared with myocardial infarction for severely head injured patients with low intracranial pressure.
or that cardiac arrest patients require a slower rewarming period. Mild Hypothermia Study Group in Japan. J Neurosurg. 2001;94:50.
One such parameter, the time between injury and the initiation of • Williams GR, Spencer FC. The clinical use of hypothermia follow-
cooling, may be the most consistent between different disease states. ing cardiac arrest. Ann Surg. 1958;148:462.
That is, the sooner a patient is cooled after a given insult, the more likely
it is to prevent tissue injury from that disease process. This has been
shown in a large variety of IR models at the cellular, organ, and whole-
animal levels. 20,52 Therefore, techniques to allow for early and rapid cool- REFERENCES
ing will need to be developed. Current external cooling methods such as Complete references available online at www.mhprofessional.com/hall
ice packing and cooling blankets take several hours to lower core body
temperatures adequately in humans. Endovascular cooling catheters
appear promising, especially for localized cooling in stroke or myocar-
dial infarction. Additional techniques involving multiphase coolants Intravascular Devices
are currently under development. One goal for induced hypothermia CHAPTER
research in cardiac arrest would be to develop a cooling method that in the ICU
could be initiated in the prehospital setting by paramedics. 27
Hypothermia induction in cardiac arrest fits squarely within the John F. McConville
metabolic phase of cardiac arrest, as part of the three-phase time-sensitive Bhakti K. Patel
model of CPR (see further discussion of the three-phase model in
Chap. 25). With the failure of defibrillation and medications to restore
102
viable hemodynamics, patients could be cooled rapidly to protect KEY POINTS
organs from ongoing ischemia and as a bridge to additional therapies
such as establishment of cardiopulmonary bypass with controlled • The subclavian approach is preferred for placement of central
reperfusion. 103-108 Under such intensive control, further attention could venous catheters (CVCs).
be given to reversal of metabolic injury caused by ROS, mediators • Real-time ultrasound may reduce the mechanical complications
of apoptosis, compromise of cell membrane integrity, and so forth. associated with CVC insertion.
The limits for reversal of ischemic injury when treated under such a • Chlorhexidine-based skin antiseptic solutions reduce the inci-
“suspended animation” paradigm remain to be determined. dence of catheter-related bloodstream infections as compared to
povidone-iodine.
• Almost 50% of hospital-acquired bloodstream infections are
KEY REFERENCES
caused by staphylococcal species.
• Bernard SA, Gray TW, Buist MD, et al. Treatment of comatose sur- • CVCs should not be replaced nor exchanged over a guide wire on
vivors of out-of-hospital cardiac arrest with induced hypothermia. a routine basis.
N Engl J Med. 2002;346:557.
• Erlinge D, Götberg M, Grines C, et al. A pooled analysis of
the effect of endovascular cooling on infarct size in patients
with ST-elevation myocardial infarction. EuroIntervention.
2013;8(12):1435-1440. Central venous catheters (CVCs) have become an integral part of
delivering care in the modern intensive care unit (ICU). In fact, the
• Hypothermia After Cardia Arrest Study Group. Mild therapeutic CDC estimates that in US ICUs there are 15 million CVC days per year
hypothermia to improve the neurologic outcome after cardiac (total number of days patients are exposed to CVCs). Indications
1
arrest. N Engl J Med. 2002;346:549. for placement of CVCs include invasive hemodynamic monitoring,
• Lakhan SE, Pamplona F. Application of mild therapeutic hypo- administration of vasoactive drugs, administration of caustic agents
thermia on stroke: a systematic review and meta-analysis. Stroke (eg, chemotherapy), administration of parental nutrition, renal replace-
Res Treat. 2012;2012:295906. Epub 2012 Feb 20. ment therapy, large bore venous access for rapid administration of
• Lebiedz P, Meiners J, Samol A, et al. Electrocardiographic fluids, and long-term venous access. This chapter will focus on the use
changes during therapeutic hypothermia. Resuscitation. 2012 of CVCs in the ICU setting. Thus, long-term tunneled catheters used
May;83(5):602-606. Epub 2011 Nov 25. for hemodialysis and peripherally inserted central catheters (PICC) will
not be discussed.

section02.indd 179 1/13/2015 2:05:16 PM