Patients with high spinal lesions lack innervation to the sympathetic splanchnic outflow. Lack of basal sympathetic tone to peripheral blood vessels results in vasodilation and postural hypotension. This is modulated over time by an increase in the renin–angiotensin system compensation resulting in a higher capacitance vessel tone. Intravascular volume is often decreased in these patients, and it is critical to ensure adequate volume resuscitation prior to induction of anesthesia. In addition, they have inadequate norepinephrine release that often magnifies the hypotension on induction.

As mentioned above, lesions above T6 interrupt the cardiac accelerator fibers resulting in bradycardia and a diminution in inotropy. As a result, patients present with high vagal tone with conduction defects, heart block, and arrhythmias. A preoperative electrocardiogram (ECG) should be routine regardless of the patient’s age.

Respiratory compromise is common not only in patients with lesions above C6, the level of innervation of the diaphragm, but in those with thoracic lesions as well. In thoracic lesions, abdominal muscle activity may be absent and intercostal activity, minimal. This impairs coughing, deep breathing, and clearing secretions [7]. Upper accessory muscles, e.g., the sternocleidomastoid and trapezius, may play a larger role in breathing. Gastric and bowel distention from autonomic dysfunction may further impair diaphragmatic excursion and increase atelectasis, as well as increased risk of regurgitation and aspiration. Kyphoscoliosis, an abnormal curvature of the spine in both a coronal and sagittal plane, is common in these patients and may aggravate these issues. Pulmonary function tests (PFTs) often show a decrease in vital capacity, functional residual capacity, and expiratory flows as well as a decrease in PaO₂ and increase in dead space and PaCO₂ secondary to the increase in atelectasis. Management may include placement of a nasogastric tube to decompress bowel, chest physiotherapy, and tracheal suctioning.

Chronic infection and colonization of the urinary tract develops early in the spinal cord-injured patient. Chronic infection leads to proteinuria, hypocalcemia, and renal insufficiency. A main cause of death in chronic spinal cord lesion patients is renal failure [8]. Patients also develop amyloidosis and hypoalbuminemia secondary to albuminuria. This can lead to significant peripheral edema and skin breakdown. These patients often need prophylactic corticosteroid administration secondary to adrenal cortical dysfunction. Adrenocorticotropic hormone (ACTH) levels can be measured to assist in monitoring adrenal function [11].

Chronic renal insufficiency also leads to a decrease in hemopoietin hormone production causing chronic anemia. This may require blood transfusions prior to surgery. The resultant renal insufficiency can also result in electrolyte and acid–base imbalances often exacerbated by treatment for constipation with enemas, diuretics for peripheral edema, and low-salt diets.

Calcium and potassium imbalances can put the patient at risk for cardiac arrhythmias if not corrected preoperatively [9].

SCI patients develop osteoporosis and muscle wasting very quickly after injury [10]. Hypocalcemia from renal insufficiency accelerates mobilization of calcium from bones resulting in a high propensity for pathologic fractures from simple movement or positioning on an operating room table. Pressure injury to the skin below the level of the SCI occurs commonly. Decubitus ulcers can develop after 2 h of continuous pressure on a skin area. The chronic anemia and hypoalbuminemia of renal insufficiency make para- and quadriplegic patients even more susceptible to this kind of injury. Secondary osteomyelitis develops at these areas, particularly the ischium, sacrum, and heels. Ulceration at the site of possible injection, fever, elevated white count, or untreated infection are contraindications to regional anesthetic block [11]. Skeletal muscle spasm can also occur after a stimulus below the level of the spinal cord lesion. This involves a spinal reflex arc. This can occur intraoperatively and interfere with the surgical procedure.

The SCI patient is poikilothermic, having a body temperature that varies with the temperature of the surroundings below the level of the spinal cord injury with loss of autonomic control cutaneous vasoactivity, sweating, and shivering. These patients are particularly susceptible to the changes in ambient temperature in an OR. They are not able to efficiently get rid of heat in a warm OR or develop hypothermia quickly in a cold OR [12].

This requires close monitoring of temperature with either an esophageal or bladder temp probe. Forced air warmers and warmed intravenous (IV) fluids should be immediately available.

Depression is common in these patients, particularly at the time of the acute lesion. Emotional strains are compounded by the work of rehabilitation economic pressures and recognition of their permanent handicap. Frequently, these problems are compounded by alcohol and drug dependence. It is important to elicit any drug or alcohol use in the preoperative interview as well as any herbal or homeopathic remedies [13].