Pro/Con Debate: Hyperkalemia-Should Surgery Proceed when Potassium - - PowerPoint PPT Presentation

Pro/Con Debate: Hyperkalemia-Should Surgery Proceed when Potassium Levels are Moderately High?

Iosifina Giannakikou, MD, MBBS. Anesthesia & Critical Care Medicine Hygeia Hospital, Athens, Greece

Hyperkalemia

• Definition
• Causes
• Clinical manifestations
• Evidence
• Conclusion

Definition

• Normal K: 3.5-5.3 mEq/L
• Hyperkalemia: K > 5.5 mEq/L
• Common electrolyte disorder (2.5% of hospitalized pts)
• McDonald. Investigating hyperkalaemia in adults. BMJ (clinical research ed).351:4762

Causes

• Pseudohyperkalemia
• extravascular hemolysis
• Decreased excretion
• Renal failure, ACEI, ARBs, K-sparing diuretics, adrenal inhibition, aldosterone

levels.

• Intracellular release
• Succinylcholine, acidosis, digoxin, Massive cell death (tumor lysis syndrome,

rhabdomyolysis, burns, crush injuries, hemolysis, blood transfusion, ischemic reperfusion, MH)

• Increased intake
• K-supplementation

Succinylcholine

• Succinylcholine muscle depolarization causes transient increase

in serum K (0.5-1 mEq/L)

• Life threatening increases in serum K in situations with:
• proliferation in the number of nicotinic receptors
• 3rd degree burns, spinal cord injuries, neuromuscular diseases.
• Grontre. Pathophysiology of hyperkalemia induced by succinyl choline. Anesthesiology 1975;43:89-99

• Sux 1mg/kg given to pts with neuromuscular disease
• 15/40 pts: K 1-6mEq/L
• Degree and extent of muscle paralysis correlate with relaxant-

induced hyperkalemia

• Cooperman. JAMA 1970;213(11):1867-1871

• 17 yo fit male for elective circumcision
• No sign PMH, no previous anesthesia Hx
• Isoflurane anesthesia used, no sux
• Cardiac arrest in PACU
• K>13 mEq/L, CK>70,000 U/L
• Undiagnosed Becker’s muscular dystrophy
• Poole. BJA 104(4):487-9 (2010)

• Cardiac arrest in healthy children within 24hrs of anesthesia
• 25 arrests (in 3 years)
• 92% males, minor surgery, median age 4 yrs old
• 92% inhalational anesthetic
• 72% and/or succinylcholine
• 72% had hyperkalemia
• 48% undiagnosed Duchenne dystrophy or unspecified myopathy
• 67% of arrests associated with hyperkalemia
• Larach. Clin Pediatr (Phila). 1997 Jan;36(1):9-16

Acidosis

• Acidosis can cause hyperkalemia by moving K extracellularly
• 98% of total body K is intracellularly
• pH by 0.1 serum K by 1 mEq/L
• Common causes of acidosis during anesthesia
• respiratory acidosis (hypoventilation)
• metabolic acidosis (diabetic ketoacidosis in a fasted diabetic, circulatory or

hemorrhagic shock, hyperchloremic acidosis with 0.9% NS)

• Sendak. Principles and Practice of Anesthesiology. 1998

• Massive blood transfusion liberates K
• K accumulated during blood preservation
• 20 mEq/L of K in 1 unit of blood stored for 21 days
• Parthasarathy. J Anesth Clic Pharmacology 2007; 23(2): 129-144

• Prolong fasting (16-26 hours) in ESRD
• Fasting hyperkalemia (due to insulinopenia)
• Gifford. Kidney Int. 1989; (35):90-94

• K>9 mEq/l induced by K sparing diuretics
• Berkova. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2014;158(1):84-91

• 49 yo on ACEI for large lipoma surgery
• pre-op K: 4.5 Cr: 0.7
• 2.5 hr later: tall T wave, K 8.07 mEq/L, Gluc 327 mg/dL
• Park. Korean j Anesthesiol. 2011;61(2):175-176

Clinical manifestations

• Asymptomatic –mild elevations
• Cardiac effects
• Neuromuscular effects

Cardiac effects

• Bradycardia
• Heart block (1st, 2nd, 3rd)
• Asystole
• AV & intraventricular conduction abnormalities
• Ventricular flutter, VT, persistent VF
• Lethal arrhythmias
• Severely depressed myocardial contractility

EKG changes

• PR prolongation
• Peaked and narrowed T waves
• Loss of P waves
• Widening of QRS complex
• Sine wave (markedly widened QRS complex merges with T wave)
• Ventricular Fibrillation
• Asystole

Double counting of HR Hyperkalemia-CORE EM

• 90 cases of K>6 mEq/L
• EKG read by cardiologist
• 46% had EKG changes
• Montague. Clin J Am Soc Nephrol. 2007;3(2):324-330

• An. Critical Care 2012,16:R225

Note: EKG vs K

• Poor sensitivity of EKG to detect hyperkalemia
• EKG changes can be “non-classic”
• i.e. AV blocks, SB, ventricular and AV junctional escape rhythms
• EKG changes not necessarily occur in order
• i.e. jump from peaked T waves to sine wave
• Clinical course is unpredictable
• sudden death can occur in the absence of sentinel EKG changes
• patients with preexisting EKG abnormalities and new hyperkalemia can

present with normalization of the EKG

• Goyal. JAMA. 2012;307(2):157-164

Duration of hyperkalemia

• Chronic hyperkalemia is better tolerated in chronic RF patients
• Degree to which tolerance is increased is not known

• Einhorn. Arch Intern Med. 1009;169(12):1156-1162

Neuromuscular effects

• Paresthesia
• Weakness
• Depressed deep tendon reflexes
• Respiratory depression
• Flaccid paralysis

• 80 yo on oral & iv K-supplementation pre-op for K
• postoperative hyperkalemia K >7.6 mEq/L
• induced residual neuromuscular blockade necessitating ventilatory

support

• Wilbanks. AANA J 2005;73:437-41

Factors influencing decision

• Urgency of surgery
• Severity/Type of surgery
• Presence of renal insufficiency
• Duration of hyperkalemia
• Hyperkalemia related reduced contractility
• Hyperkalemia related conduction disturbance
• Presence of systemic disease that may be aggravated by K
• Presence of metabolic imbalances that may aggravate K

• Insensitive and non-specific ECG changes to hyperkalemia
• Unknown tolerance of chronic hyperkalemic patient to acute in K
• Unexpected change of metabolic status
• Unexpected need for succinylcholine administration
• Unanticipated change from a short minor case to a long complicated

case

• Undiagnosed myopathy

Postpone elective surgery for K > 5.5 mEq/L