Intraoperative management of potentially fatal arrhythmias after anesthesia induced by severe hypokalemia: A case report / 北京大学学报(医学版)

Severe hypokalemia is defined as the concentration of serum potassium lower than 2.5 mmol/L, which may lead to serious arrhythmias and cause mortality. We report an unusual case of potentially fatal ventricular arrhythmias induced by severe hypokalemia in a patient undergoing laparoscopic partial nephrectomy in Peking University Third Hospital due to irregular use of indapamide before operation. Indapamide is a sulfonamide diuretic with vasodilative and calcium antagonistic effects, which enhances sodium delivery to the renal distal tubules resulting in a dose-related increase in urinary potassium excretion and decreases serum potassium concentrations. The electrolyte disorder caused by the diuretic is more likely to occur in the elderly patients, especially those with malnutrition or long-term fasting. Hence, the serum potassium concentration of the patients under indapamide therapy, especially elderly patients, should be monitored carefully. Meanwhile, the potassium concentration measured by arterial blood gas analysis is different from that measured by venous blood or laboratory test. According to the previous research, the concentration of potassium in venous blood was slightly higher than that in arterial blood, and the difference value was 0.1-0.5 mmol/L. This error should be taken into account when rapid intravenous potassium supplementation or reduction of blood potassium level was carried out clinically. In the correction of severe hypokalemia, the standard approach often did not work well for treating severe hypokalemia. The tailored rapid potassium supplementation strategy shortened the time of hypokalemia and was a safe and better treatment option to remedy life-threatening arrhythmias caused by severe hypokalemia with a high success rate. Through the anesthesia management of this case, we conclude that for the elderly patients who take indapamide or other potassium excretion diuretics, the electrolyte concentration and the general volume state of the patients should be comprehensively measured and fully evaluated before operation. It may be necessary for us to reexamine the serum electrolyte concentration before anesthesia induction on the morning of surgery in patients with the history of hypokalemia. For severe hypokalemia detected after anesthesia, central venous cannulation access for individualized rapid potassium supplementation is an effective approach to reverse the life-threatening arrhythmias caused by severe hypokalemia and ensure the safety of the patients.

Evidence of waveform information in arterial blood gas by beat-by-beat sampling method in patients with normal heart function / 中国应用生理学杂志

<p><b>OBJECTIVE</b>Since 2011 EB-APS conference, we hypotheses that phase switching of inspiration-expiration is dominantly initiated by oscillatory information PaO2, PaCO2 and [H+] via fast peripheral chemical receptors. However, the evidence of the waveform of ABG is lack.</p><p><b>METHODS</b>Six surgery patients with normal heart function and negative Allen test, had been placed the arterial catheterization directly connected to 3 x 1 000 mm pre-heparin plastic pipe for continuous collecting arterial blood. We counted the number of heart beat for the blood collecting time, and separated the blood pipe into the heart beat numbers' short pieces using haemostatic forceps, then put pipe into iced water at once fir analyzing PaO2, PaCO2, pH and SaO2 as soon as possible. We selected two breaths cycles of waveform from each patient for data calculations of magnitudes and time interval.</p><p><b>RESULTS</b>The heart beat numbers for filling blood into pipe were 16 ± 2, and all covered more than 2 breathing cycles. Each breathing cycle is cover 5 ± 0.6 heart beat. There were significant changes of PaO2, PaCO2, [H+] a and SaO2 (i.e. the highest high values compare to the next lowest values, P < 0.05). The time interval of changing PaO2, PaCO2, [H+]a and SaO2 magnitudes were 11.28 ± 1.13 mmHg, 1.77 ± 0.89 mmHg, 1.14 ± 0.35 nmol/L and 0.52% ± 0.44% respectively.</p><p><b>CONCLUSION</b>This simple continuous beat-by-beat arterial blood sampling and ABG analyzing method is new and practicable. We obtain a clear evidence of periodic parameters ABG waveform, which following breathing cycle.</p>

Evidence of waveform information in arterial blood gas by beat-by-beat sampling method in patients with heart failure / 中国应用生理学杂志

<p><b>OBJECTIVE</b>We investigate the magnitudes of waveform changes of arterial blood gas (ABG) in patients with heart failure.</p><p><b>METHODS</b>Five patients with heart failure were selected, continuous collecting radial artery blood and measured PaO2, PaCO2, pHa and Sao2. We selected two typical breaths cycles of waveform changes of ABG from each patient for data analysis. Comparison of the adjacent highest and lowest values to verify the presence of a periodic waveform changes of ABG, and in addition, we used t test to analysis the range of waveform changes of ABG in patients with heart failure and patients with normal cardiac function and compared whether the difference between them.</p><p><b>RESULTS</b>The 5 patients (2 surgical and 3 ICU) with heart failure, were 4 male and 1 female, (69 ± 7)year, (169 ± 10) cm, (75 ± 19)kg, LVEF = (38 ± 3)%. The heart beat numbers for full blood into the blood sampling pipe were 17 ± 2, and all covered more than 2 breath cycles. There were significant changes of PaO2, PaCO2, [H+]a and SaO2 (P < 0.05). The magnitudes of changing PaO2, PaCO2, [H+]a and Sao2 were (7.94 ± 2.02)mmHg, (1.18 ± 0.56)mmHg, (0.54 ± 0.17)nmol/L and (0.21 ± 0.07)%, and they were (6.1 ± 1.5)%, (3.2 ± 1.5)%, (1.5 ± 0.5)% and (0.2 ± 0.1)% from their mean respectively. Even these magnitudes fo all ABG parameters were trendily lower than those of patients with normal cardiac function, but only PaO2 and [H+]a were significant (P < 0.05).</p><p><b>CONCLUSION</b>Using this simple continuous beat-by-beat arterial blood sampling method, we obtained a clear evidence of periodic waveform of ABG parameters following by breath cycle in patients with heart failure, but the magnitude trendily be decreased.</p>

Better parameters of ventilation-CO₂output relationship predict death in CHF patients / 中国应用生理学杂志

<p><b>OBJECTIVE</b>Measures of ventilation-CO₂output relationship have been shown to be more prognostic than peak O₂uptake in assessing life expectancy in patients with chronic heart failure (CHF). Because both the ratios (VE/Vco₂) and slopes (VE-vs-Vco₂) of ventilation-co₂ output of differing durations can be used, we aim to ascertain which measurements best predicted CHF life expectancy.</p><p><b>METHODS</b>Two hundred and seventy-one CHF patients with NYHA class II-IV underwent incremental cardiopulmonary exercise testing (CPET) and were followed-up for a median duration of 479 days. Four different linear regression VE-vs- Vco₂ slopes were calculated from warm-up exercise onset to: 180 s, anaerobic threshold (AT), ventilatory compensation point (VCP); and peak exercise. Five VE/Vco₂ ratios were calculated for the following durations: rest (120 s), warm-up (30 s), AT (60 s), lowest value (90 s), and peak exercise (30 s). Death or heart transplant were considered end-points. Multiple statistical analyses were performed.</p><p><b>RESULTS</b>CHF patients had high lowest VE/Vco₂ (41.0 ± 9.2, 141 ± 30%pred), high VE/Vco₂ at AT (42.5 ± 10.4, 145 ± 35%pred), and high VE-vs-Vco₂ slope to VCP (37.6 ± 12.1, 126 ± 41%pred). The best predictor of death was a higher lowest VE/Vco₂ (≥ 42, ≥ 141%pred), whereas the VE-vs-Vco₂slope to VCP was less variable than other slopes. For death prognosis in 6 months, %pred values were superior: for longer times, absolute values were superior.</p><p><b>CONCLUSION</b>The increased lowest VE/Vco₂ ratio easily identifiable and simply measured during exercise, is the best measurement to assess the ventilation-co₂output relationship in prognosticating death in CHF patients.</p>