Hypokalemia Case Study

Author/s

Shawn Maskalick, Chinwe Okoro, Logan Simcox, Ali Hasnie

Bellarmine University

Doctor of Physical Therapy program

Class of 2016

Patient Characteristics

• Demographic Information: 75 y/o white female retired high school teacher living in nursing home

• Medical diagnosis: Acute hypoxic respiratory failure secondary pulmonary edema
• Co-morbidities: PMH of Coronary Artery disease. S/P CABG, IDDM, HTN, CKD stage 3. 
• Previous care or treatment: Multiple hospital admissions for acute exacerbation of systolic heart failure and respiratory distress secondary to fluid overload.

Examination

• Subjective: 75 y/o white female, NH resident w/PMH of Coronary Artery disease. S/P CABG, CHF with EF 20% on diuretics, IDDM, HTN, CKD stage 3 presents to the ED with c/o dyspnea for 2 days. According to her caregiver and the family, she has had difficulty breathing on minimal exertion and appear winded at rest. She is unable to ambulate and has been lethargic for 3 days. According to the family, since her d/c from the hospital one month ago her respiratory status has not returned to her baseline health. She has been requiring 2L oxygen via nasal cannula and few days ago her lasix dose was doubled. Her quality of life has significantly decline in the last month and she requires 24 hour assistance.
• Objective: She appears chachectic, in respiratory distress using her accessory muscles, unable to complete her sentence. Tachycardia, tachypnea, hypotension, hypoxic, audible S1, S2, 3/6 ESM at the right sternal border. abd soft, non distended, pulses are+1 of lower extremities. She is alert to person, place and time, no focal neurologic deficit.

Clinical Impression:

1. Acute hypoxic respiratory failure secondary pulmonary edema
2. Acute on chronic CHF exacerbation
3. Hypokalemia and hypomagnesium secondary to loop diuretics

Summarization of Examination Findings

Based on the subjective and objective findings, the targeted interventions include replacing potassiumvia IV and monitor for other possible electrolyte imbalances. The patient's diuretics should be monitored accordingly since it may cause unwanted side effects. Goal is to make patient euvolemic and if unable to do so with diuretics then consult nephrology for hemodialysis. Upon discharge she will need potassium supplements with her loop diuretic therapy and will need BMP check in 1 week and follow-up with heart failure clinic in one week.

Targeted Intervention (Medical): Replace the potassium via IV, correct all the electrolyte abnormalities, and continue diuresis for fluid overload.

Targeted Intervention (Physical Therapy): Deep breathing, postural drainage, percussion and vibration, strength and mobility exercises.

Intervention

Once potassium levels have normalized, physical therapywill reasses patient. Before ambulating patient from bed, physical therapist will continue to monitor vitals throughout treatment session. Therapist will address impairements and functional deficits patient may display. Physical therapy can also work on breathing exercises to improve oxygen consumption. 

Physical therapy is contraindicated if Potassium levels are <3.5 - >5.0.

Patient is usually on bed rest by physician's order until Potassium levels are nomalize.

Phases of Interventions:

Phase 1 - Since patient is suffering from pulmonary edema secondary to acute hypoxic respiratory failure, physical therapy will work on breathing exercises, postural drainage (precaution for PE), vibration and percussion. Educate patient on deep breathing and sitting posture to minimize the fluid accumulation.

Phase 2 - Patient is classified as NYHA class 3 meaning patient has marked limitation of physical activity. She is comfortable at rest but less than ordinary activity causes fatigue, palpitation, dyspnea or anginal pain. Physical therapy will keep these symptoms in mind and get the patient out of bed to work on mobility. Physical therapy will monitor O2 sats before, during, and after the treatment sessions and patient will be able to rate their fatigue level on Perceive level of Exertion scale. Physical therapy will teach and educate patient on energy conservation technique.

Phase 3 - Usually patients with pulmonary edema has an average of 5-7 days length of stay. Physical therapy will work with patient everyday while monitoring vitals and fatigue well.

• Dosage and Parameters (Medical)
  

1. IV lasix 40mg q8hr
2. IV potassium chloride bolus 40mg times 2 and recheck potassium in 4 hours
3. IV magnesium sulfate bolus 2gm
4. Consult cardiology

• Dosage and Parameters (Physical Therapy)
  

Deep breathing, Percussion and Vibration: start off with deep breathing exercises for few minutes. Percussion and Vibration 3-5 minute per segment, start with most congested first of day. Follow with deep breathing, coughing, suctioning as needed.
Aerobic: low impact and short distance ambulation as per patient's tolerance. Progress to longer distance and stairs while monitoring O2 sats and patients fatigue levels.
Strength: In-bed exercises such as ankle pumps, isometric quad/hamstring contractions, heel slides, SLRs, glut isometrics, hip Add/Abd. 2-3 sets x 10 reps or as patient tolerance

• Rationale for Progression
• Progress patient to their prior level of function, increase endurance, and improve quality of life.
  Increase patients activity tolerance level while minimizing NYHA classification level.
  

Outcomes

According to the physician's recommendation, patient was treated with potassium chloride, magnesium sulfate, and lasix. Patient's potassium levels were normalized in about 4 hours. 

According to Turcotte, treatment of any acute episode of muscle weakness includes providing a secure airway, effective ventilation, and circulatory stabilization. Normlization of potassium may include an oral supplement of 0.2 to 0.4 mmol/kg every 15 to 30 minutes over 1 to 3 hours with a total dose nto to exceed 200 mEg in 24 hours in order to avoid rebound hyperkalemia and its associated sequelae. 

Discussion

The presentation of hypokalemia is sometimes hard to diagnose initially. Hypokalemia is defined by potassium serum levels below 3.5mEq/L. Patients commonly diagnosed with this electrolyte imbalance include individuals who are on diruretics such as Lasix or laxatives. Other common causes may include chronic diarrhea, vomiting, malnourishment, alcoholism, burns, gastric suction-NG. 

Individuals with Cushing's syndrome may experience hypokalemia, however those with Guillain Barre syndrome may mimic the signs and symptoms of hypokalemia. 

Patients with hypokalemia may present with signs and symptoms of muscle cramping, fasiculations, paralytic ileus, tetany, and rhabdomyolysis, weakness (can lead to paralysis), constipation, abdominal distention, anorexia, nausea, confusion and lethargy, respiratory failure, hypoventilation, hypotension, arrhythmias, cardiac arrest, and cardiac rhythm disturbance. At very low levels, ventricular tachycardia may occur.

Patients who present to physical therapy with complaints of muscle weakness and muscle cramping should be examine thoroughly for general weakness. Physical therapist should take a thorough history and be aware of any signs and symptoms related to electrolyte imbalance. The potential impact of the presentation of hypokalemia in clinical practice may suggest  that patients may not fully respond to physical therapy if the electrolytes are not normalized. If a physical therapist suspects any signs and symptoms to be present, they should refer the patient out immediately to be evaluated by a physician. 

Related Pages

http://www.airmedicaljournal.com/article/S1067-991X(13)00079-5/abstract?showall=true=

References

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1. Turcotte J, White D, Tilney PV.. Hypokalemic periodic paralysis: two cases of profound weakness.. Air medical journal 2013; 32(4):181-183;189 .