SAFE POSITIONING FOR NEUROSURGICAL PATIENTS

AORN Journal, June, 2008 by Danielle St-Arnaud, Marie-Josee Paquin

Positioning the patient for surgery is an important part of perioperative nursing care. Although it can become routine, its importance should not be underemphasized because the combined factors of time, mechanical pressure, and immobility increase the patient's risk of tissue damage. (1) The neurosurgical perioperative team faces additional challenges related to positioning because of the potential for complications during prolonged and complex procedures. Perioperative neurosurgical nurses are responsible for the safety of their patients, and safe positioning ranks high on their list of priorities. As do all perioperative nurses, the neurosurgical nurses at Montreal Neurological Hospital, Quebec, Canada, apply principles of anatomy and physiology to the process of positioning surgical patients. In many circumstances, the OR team must use creative methods to protect their patients from mechanical injury and maintain cardiovascular, pulmonary, and other physiological functions. Technological advances in specialty positioning devices also have contributed to improved patient outcomes. (1,2) This article discusses general principles of positioning as well as the most frequently used positions for neurosurgery: supine, knee-chest, prone, lateral, park-bench, and sitting.
GENERAL PRINCIPLES OF POSITIONING
Safely positioning the patient must be a team effort; each member of the surgical team plays a significant role and shares the responsibility for establishing and maintaining the correct patient position. Each member of the team brings his or her knowledge of anatomy and physiology, as well as experience in using various positioning aids and accessories, to the safe positioning of patients.
The primary objective of these activities is to balance optimal surgical exposure with the prevention of any injury related to positioning. At Montreal Neurological Hospital, the perioperative team involved with positioning consists of the circulating nurse, neurosurgeon, anesthesia care provider, and patient attendant. Throughout the intraoperative period, it is the circulating nurse's responsibility to preserve the patient's dignity, safety, and physical well-being. One of the circulating nurse's most important responsibilities is performing the preoperative assessment of each patient in regard to positioning risk factors and documenting any preexisting conditions.

POSITIONING ACTIVITIES.
The circulating nurse is responsible for coordinating positioning activities and is an active participant in safely positioning the patient. Furthermore, the circulating nurse ensures that a sufficient number of personnel are available to position the patient safely and effectively. The neurosurgeon determines optimal exposure of the surgical site, the anesthesia care provider ensures physiological stability, and the patient attendant prepares and installs positioning devices and equipment.
After the neurosurgeon determines appropriate exposure of the surgical site but before the patient is transferred to the OR bed, the circulating nurse ensures that all positioning devices and equipment are readily available, in proper working order, and clean. Positioning devices should be able to perform the following functions effectively:
* absorb compressive forces,
* prevent uneven and potentially excessive pressure distribution,
* prevent excessive stretching or compression, and
* allow chest expansion for proper ventilation and gas exchanges.
Normal body alignment must be maintained without excess flexion, extension, or rotation. For example, extreme rotation of the head can cause pressure on the carotid sinus and induce hypotension and arrhythmias or restrict venous outflow leading to congestion. (3) The nurse and anesthesia care provider work cooperatively to ensure that direct pressure on the patient's eyes is avoided to minimize the risk of central retinal artery occlusion and other ocular damage (eg, corneal abrasion). If possible, the patient is positioned so that his or her head is level with or higher than the heart and is maintained in a neutral forward position without significant neck flexion, extension, lateral flexion, or rotation. (4)
The anesthesia care provider requires access to IV lines and monitoring devices throughout the procedure to monitor and control the patient's physiological functions. The anesthesia care provider ensures that there is adequate room for chest and abdominal expansion to protect the patient's respiratory functions. The circulating nurse applies thromboembolic disease (TED) stockings or intermittent pneumatic sequential compression devices (SCDs) to reduce blood pooling in the legs; the nurse also applies SCDs if the patient is undergoing a surgical procedure with general anesthesia that will last longer than 30 minutes. (5)

MAINTAINING NORMOTHERMIA. Maintaining normothermia in relation to positioning is important." (6) The fall in core temperature that occurs after induction of anesthesia leads to a peripheral vasoconstriction, which can result in peripheral hypo-perfusion and cell hypoxia. (6) The tissue-damaging effects of pressure are more likely to occur after a decrease in oxygen delivery.
To be continued……………