Equipment and Therapeutic Modalities Flashcards

A physical therapist is applying therapeutic ultrasound to treat soft tissue shortening of the hip joint capsule. To achieve a vigorous thermal effect in this deep tissue, which of the following parameter settings is MOST appropriate?

Answer: Frequency: 1 MHz, Duty Cycle: 100% (Continuous), Intensity: 1.5 W/cm²

To achieve a thermal effect in deep tissues (up to 5 cm), a frequency of 1 MHz is required. A 100% continuous duty cycle ensures constant energy delivery for heating. An intensity of 1.5 to 2.0 W/cm² is typically needed to produce vigorous heating at this depth. The other options are incorrect because 3 MHz is for superficial tissues, and pulsed duty cycles (20%, 50%) are used for non-thermal effects.

A physical therapist is treating a patient with acute pain using conventional Transcutaneous Electrical Nerve Stimulation (TENS). According to the Gate Control Theory of pain, which parameters are MOST effective for this mode of TENS?

Answer: High frequency (80-100 Hz), short pulse duration (50-100 µs), low intensity (sensory level)

Conventional TENS for acute pain management operates based on the Gate Control Theory. This is best achieved by stimulating large-diameter A-beta sensory fibers without causing muscle contraction. The optimal parameters for this are a high frequency (typically 50-100 Hz), a short pulse duration (50-200 µs), and a comfortable sensory-level intensity. The other options describe parameters for acupuncture-like TENS or brief-intense TENS, which operate via different mechanisms.

A patient with lymphedema in the right lower extremity is prescribed intermittent pneumatic compression (IPC). To effectively reduce the edema, which of the following treatment parameters is MOST appropriate and safe?

Answer: Inflation pressure of 45 mmHg, on:off cycle of 90:30 seconds, treatment time of 60 minutes

Evidence suggests that for lymphedema, effective IPC treatment involves pressures between 30-60 mmHg, applied for 45-60 minutes. A longer inflation time (e.g., 90 seconds) followed by a shorter deflation time (e.g., 30 seconds) in a 3:1 ratio is a common and effective protocol. Pressures should not exceed the patient's diastolic blood pressure to avoid occluding arterial flow. Pressures as high as 90 or 110 mmHg are generally considered excessive and potentially unsafe for lymphedema.

A physical therapist is using iontophoresis to deliver dexamethasone to treat lateral epicondylitis. Given that dexamethasone sodium phosphate has a negative polarity, which of the following setups is correct?

Answer: The medication should be placed on the cathode (-), and the dispersive pad should be the anode (+).

The principle of iontophoresis is based on the concept that like charges repel. Since dexamethasone is a negatively charged ion, it must be placed under the negative electrode (cathode) to be repelled and driven into the underlying tissues. The dispersive pad must have the opposite polarity, making it the anode (+), to complete the electrical circuit.

A patient is referred for mechanical lumbar traction for a suspected herniated nucleus pulposus. Which of the following conditions in the patient's medical history is an absolute contraindication for this treatment?

Answer: Aortic aneurysm

An aortic aneurysm is an absolute contraindication for mechanical traction. The pressure from the traction harness across the abdomen could potentially increase pressure on the weakened aortic wall, risking rupture, which is a medical emergency. While conditions like severe COPD or claustrophobia may require modification of the treatment or cause patient intolerance, they are considered relative contraindications or precautions. An acute ligamentous sprain is also a contraindication, but an aortic aneurysm represents a more severe, systemic risk.

A physical therapist is designing a protocol using neuromuscular electrical stimulation (NMES) to improve quadriceps muscle strength following an ACL reconstruction. To elicit a tetanic contraction for muscle strengthening, which frequency range is MOST appropriate?

Answer: 35-50 Hz

For muscle strengthening with NMES, the goal is to produce a smooth, tetanic muscle contraction. This is typically achieved with a frequency between 30 and 50 Hz. Frequencies below this range (e.g., 1-10 Hz) will produce individual muscle twitches, which is not effective for strengthening. Frequencies significantly above this range (e.g., >75 Hz) can lead to more rapid muscle fatigue without providing additional benefit for force production.