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Background: Speech perception in noise is especially challenging for cochlear implant (CI) recipients; thus, speech in noise tests are used to clinically evaluate functional hearing with CIs. The coordinate response measure (CRM) corpus can be utilized in an adaptive speech perception test with competing speakers as the masker. Determining the critical difference for CRM thresholds can enable it to be used to evaluate changes in CI outcomes for clinical and research purposes. If a change in CRM exceeds the critical difference, then this would indicate significant improvement or decrement in speech perception. Additionally, this information provides figures for power calculations that could be used for planning studies and clinical trials [Bland JM: An Introduction to Medical Statistics, 2000]. Objectives: This study determined the test-retest reliability of the CRM for adults with normal hearing (NH) and adults with CIs. The replicability, variability, and repeatability of the CRM were evaluated for the two groups separately. Method: Thirty-three NH adults and thirteen adult CI recipients were recruited and tested with the CRM twice, 1 month apart. The CI group was tested with two talkers only, while the NH group was tested with seven talkers as well as two talkers. Results: CRM had better replicability, repeatability and lower variability for the CI adults compared to NH adults. The critical difference (at p < 0.05) in the two-talker CRM speech reception thresholds (SRTs) among CI users was >5.2 dB, and it was >6.2 dB for the NH if an individual were to be tested under two different conditions. The critical difference (at p < 0.05) in the seven-talker CRM SRT was >6.49. The Mann-Whitney U test showed that CI recipients’ CRM scores’ variance (Mdn = −0.94) was significantly less than the NH group’s (Mdn = 2.2) (U = 54, p < 0.0001). Although the NH had significantly better SRTs in the two-talker condition than in the seven-talker condition (t = −20.29, df = 65, p < 0.0001), the Wilcoxon signed ranks test showed no significant difference between the CRM scores’ variance in the two conditions (Z = −1, N = 33, p = 0.08). Conclusions: NH adults had significantly lower CRM SRTs than the CI recipients; t (31.16) = −23.91, p < 0.001. CRM had better replicability, stability and lower variability for the CI adults compared to NH adults.

Background: Perioperative arrhythmia is a common general anesthesia complication of cardiothoracic surgeries. Sudden or acute onset of life threatening perioperative arrhythmias are rare clinical events in non-cardiac surgical patients.1,2 Electrolytes imbalance, particularly hypokalemia and dyskalemia, is one of the main possible underlining cause for the occurrence of these arrhythmias.3,4,5 We present two cases of severe hypokalemia leading to life threatening cardiac arrhythmias in the post-operative period. Case 1: A 30-year old healthy female patient without significant past medical history had emergency laparoscopic cholecystectomy and appendicectomy. Pre- and intra-operative periods were uneventful. Her pre-operative potassium level was 3.7 mmol/L. 18 hours post-operatively, she suddenly developed palpitations and went into ventricular fibrillation (VF) cardiac arrest. Cardiopulmonary resuscitation (CPR) was initiated followed by defibrillation which reverted the heart to a sinus rhythm. She was transferred to the intensive care unit (ICU) sedated and connected to the ventilator. In ICU, her serum electrolytes showed severe hypokalemia (serum potassium level 2.2 mmol/L) (Figure 1) so she was immediately started on 20 mmol of potassium chloride (KCl) over 30 minutes through central venous catheter (CVC) with complementary intravenous fluids with KCl. In the next 36 minutes she had four episodes of VF requiring CPR and defibrillation with a positive outcome. She received amiodarone infusion as well as continuous KCl supplementation and calcium gluconate 2 g. She received 100 mmol of KCl in 6 hours and a total of 220 mmol of KCl in 24 hours, and then she became stable. She was extubated after 48 hours. Echocardiogram and cardiac conduction studies showed no pathological changes. Cardiac conduction studies (electrophysiology study - EPS) were normal. She was discharged home and followed in the outpatient clinic. Case 2: A 78-year old known hypertensive male patient on angiotensin converting enzyme inhibitors was admitted to intensive care unit (ICU) for observation after laparoscopic cholecystectomy. Pre-operative serum electrolytes were within normal range. After one hour he started to have tachycardia and then went into pulseless ventricular tachycardia requiring defibrillation. His serum electrolytes results showed severe hypokalemia (2.4 mmol/L) (Figure 1) so this was corrected by rapid potassium chloride administration through CVC and supplementation of KCl in intravenous fluids. After 10 minutes he went into VF requiring defibrillation and a bolus of amiodarone. In the next 20 minutes he had three more episodes of VF requiring CPR and defibrillation. In six hours he required 90 mmol of KCl to reach a serum potassium level of 3.7 mmol/L. A total of 210 mmol of KCl was needed in 24 hours. He was extubated after 24 hours. He was transferred to the ward on day 3 and discharged home on day 6, and later followed in the outpatient clinic. Conclusion: Perioperative severe hypokalemia can lead to life threatening cardiac arrhythmias. Early recognition and aggressive correction through perioperative potassium supplementation is essential for better outcome. Daily potassium level assessment and supplementation should be done in the perioperative period.

Decompensated hypothyroidism is a rare endocrine emergency but a differential that should be considered in patients presenting critically unwell with systemic illness. We report a case of myxoedema coma in a woman presenting with respiratory failure, hypotension, hypothermia and a reduced level of consciousness, all of which are poor prognostic features in decompensated hypothyroidism. The patient was admitted to critical care for mechanical ventilation and cardiovascular support and treated with a combination of insulin, liothyronine and levothyroxine, making a good recovery. We wanted to highlight this case of myxoedema coma occurring in the context of a hyperglycaemic hyperosmolar state (HHS), as the former condition is normally associated with hypoglycaemia, hyponatraemia and hypo-osmolality. Decompensated hypothyroidism should be considered in presentations of HHS as well as with other metabolic derangements, as delays in thyroid hormone replacement are associated with poorer outcomes. It has multisystem effects challenging its recognition and we discuss potential complications and their management.