Phenylephrine

INTRODUCTION

Indications

Management of hypotension associated with shock that may persist after adequate fluid replacement. Management of hypotension associated with anesthesia. Management of paroxysmal supraventricular tachycardia. Anesthesia adjunct: Prolongation of the duration of spinal anesthesia, Localization of the effect of regional anesthesia.

Action

Constricts blood vessels by stimulating alpha-adrenergic receptors. Therapeutic Effects: Increased blood pressure. Restoration of normal sinus rhythm.

Adverse Reactions/Side Effects

CNS: anxiety, dizziness, headache, insomnia, nervousness, restlessness, trembling, weakness. Resp: dyspnea, respiratory distress. CV: ARRHYTHMIAS, bradycardia, chest pain, hypertension, tachycardia, vasoconstriction. Derm: blanching, pallor, piloerection, sweating. Local: phlebitis, sloughing at IV sites. Neuro: tremor.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Although intended to treat certain arrhythmias, this drug can unmask or precipitate new arrhythmias (proar-rhythmic effect). Report any rhythm disturbances or symptoms of increased arrhythmias, including palpitations, chest pain, shortness of breath, fainting, and fatigue/weakness.

• Assess blood pressure when patient is lying down. Compare to normal values (See Appendix F), and report a sustained increase in blood pressure (hypertension) to the physician.

• Monitor signs of peripheral vasoconstriction, such as extreme coldness in the hands and feet, cyanosis, and muscle cramping. Notify physician of severe or prolonged signs of vasoconstriction.

• Assess symptoms of respiratory distress including dyspnea, shortness of breath, and cyanosis. Monitor pulse oximetry and perform pulmonary function tests (See Appendix I) to quantify suspected changes in ventilation and respiratory function. Excessive respiratory depression requires emergency care.

• Monitor and report signs of CNS toxicity, including nervousness, anxiety, restlessness, sleep loss, and trembling/tremors. Sustained or severe CNS signs may indicate overdose or excessive use of this drug.

• Assess dizziness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

• Assess administration site and report signs of irritation, skin damage, or phlebitis (local pain, swelling, inflammation).

Interventions

• Because of the risk of cardiovascular stimulation, use caution during aerobic exercise and endurance conditioning. Assess exercise tolerance frequently (blood pressure, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

• If used to prolong regional or spinal anesthesia, be sure that sensation has returned to the affected areas before applying manual techniques or physical agents (heat, cold, electrotherapeutic devices).

Patient/Client-Related Instruction

• Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged headache or skin reactions (pallor, blanching, increased ...