Incidence of hypophosphataemia after ICU admission in mechanically ventilated patients and its relationship with risk factors for refeeding syndrome

OBJECTIVE

To describe the incidence of hypophosphatemia in patients admitted to the ICU who have required mechanical ventilation. To analyze the presence of risk factors and its relationship with nutritional practice.

DESIGN

Prospective observational study.

SETTING

Polyvalent ICUs of 2 University Hospitals.

PATIENTS OR PARTICIPANTS

Patients on invasive mechanical ventilation ≥72 h with normal level of phosphorus at admission.

INTERVENTIONS

None.

MAIN VARIABLES OF INTEREST

Electrolyte levels (phosphorus, magnesium, potassium) were determined on admission to the ICU and at 96 h. Risk categories on admission, caloric intake, insulin doses and acid-base status during the first 4 days of admission were recorded. Incidence was calculated as the number of patients who developed hypophosphataemia after admission. Univariate analysis was performed for between-group comparison and multivariate analysis of potential risk factors.

RESULTS

89 patients were included. The incidence of hypophosphataemia was 32.6%. In these patients phosphorus decreased from 3.57 ± 1.02 mmol/l to 1.87 ± 0.65 mmol/l (52.3%). The mean kcal/kg/24 h provided in the first 4 days was 17.4 ± 4.1, with no difference between the group that developed hypophosphataemia and the group that did not. Significant risk factors were insulin doses administered and pH and PaCO2 values.

CONCLUSIONS

The incidence of hypophosphataemia at 96 h from admission in mechanically ventilated patients is high and unrelated to the risk category and hypocaloric nutritional practice used. Insulin dosis and acid-base status are the main determinants of its occurrence.

Panic Attack, Severe Hypophosphatemia and Rhabdomyolysis in the Setting of a Motor Functional Neurological Disorder

(1) Background: panic attack is often regarded as a benign disorder with variable physical and psychological symptoms. (2) Case Presentation: We here report the case of a 22-year-old patient known for an episode of motor functional neurological disorder a year earlier who presented a panic attack with hyperventilation causing severe hypophosphatemia and rhabdomyolysis, as well as mild tetraparesis. Electrolyte disturbances quickly resolved after phosphate substitution and rehydration. However, clinical signs suggesting a relapse of a motor functional neurological disorder appeared (improved walking with dual tasks). Diagnostic workup, including brain and spinal magnetic resonance imaging, as well as electroneuromyography and genetic testing for hypokalemic periodic paralysis, was unremarkable. Tetraparesis, lack of endurance, and fatigue eventually improved after several months. (3) Conclusions: the present case report highlights the intertwined relationship between a psychiatric disorder, leading to hyperventilation and acute metabolic disturbances, and functional neurological manifestations.

Biochemical and Anthropometric Nutritional Assessment in Children Infected with COVID-19: A Cross-sectional Study

Background: Severe acute respiratory syndrome has led to a pandemic of coronavirus disease 2019 (COVID-19). Malnutrition either biochemically or anthropometrically is a well-known risk factor for COVID-19 and may be the vice versa Objectives  : To investigate the prevalence of malnutrition in children infected with COVID-19 through evaluating the nutritional biomarkers such as serum electrolytes, serum albumin and hemoglobin together with the anthropometric assessment.  Methods: A cross sectional study that was conducted at ElMatria Teaching Hospital for all children admitted with confirmed COVID-19 over a period of 6 months from 1st February 2021 to the end of July, 2021. Nutritional biochemical evaluation included serum electrolytes particularly   the potassium and other nutritional biomarkers such  as serum albumin and hemoglobin. Nutritional anthropometric evaluation depended on BMI (body mass index), the height/length, weight for length and weight for height..The prevalence of malnutrition esp. hypokalemia was the main outcome. Results: Hypokalemia was present in 21.8% of the study participants . Other nutritional biomarkers were found  as hyponatremia, hypocalcemia , hypophosphatemia, hypomagnesemia were detected in 49.1% , 38.2%,21.8% and 34.5%  of the study subjects respectively. Anthropometric malnutrition was present in most of the enrolled children with COVID-19 in the study (65.5 %  (n= 36) )through which overweight and obese children occupied a greater percentage. Conclusion: Malnutrition either biochemically or anthropometrically could be linked to   COVID-19 in children. COVID-19 could have negative outcomes on the nutritional status such as electrolytes disturbances. Both malnutrition and COVID-19 are considered synergistic associations   Keywords: Malnutrition. COVID-19. Children. Hypokalemia. Obesity

Severe Protracted Hypophosphatemia in a Patient with Persistent Vegetative State on Long-Term Assisted Respiratory Support

BACKGROUND Phosphorous is an essential component of cell structure and physiology, and is required for energy conservation and expenditure. Severe hypophosphatemia can lead to profound dysfunction and injury affecting most organs and can be life-threatening. It can also compromise weaning of mechanically ventilated patients. Long-term assisted ventilatory care in ambulatory or inpatient settings is an expanding medical service for patients with various forms of persistent or progressive incapacitating diseases. Hypophosphatemia, caused by respiratory alkalosis, has been reported in critical-care settings, but its occurrence in medically stable patients requiring long-term respiratory support has not been thoroughly investigated. CASE REPORT We report the case of a ventilated patient in a chronic vegetative state displaying progressive hypophosphatemia spanning over 3 months, with plasma levels gradually declining to 0.8 mg/dL. Evaluation did not reveal conditions leading to diminished phosphate absorption or enhanced urinary phosphate excretion, but it identified respiratory alkalosis related to a recent increase in target minute-volume ventilation in the adaptive support ventilation (ASV) mode as the cause of hypophosphatemia. Despite the very low plasma phosphate level, the patient was asymptomatic, probably because this type of hypophosphatemia may not represent physiologically significant intracellular phosphate depletion. The respiratory alkalosis resolved upon decreasing the target minute-volume ventilation settings, and serum phosphate was normalized. CONCLUSIONS Since blood gases are not routinely monitored in respiratory and hemodynamically stable patients on long-term respiratory support, hypophosphatemia may herald the development of significant respiratory alkalosis. Assessment of acid-base balance is thus warranted in patients receiving long-term ventilation, especially in those developing hypophosphatemia.

Hypophosphatemia at Admission is Associated with Increased Mortality in COVID-19 Patients

Background

Electrolyte disturbances are commonly observed in patients with coronavirus disease 2019 (COVID-19) and associated with outcome in these patients. Our study was designed to examine whether hypophosphatemia is associated with mortality in COVID-19 patients.

Methods

Patients diagnosed with COVID-19 and hospitalized in Renmin Hospital of Wuhan University between January 30 and February 24, 2020 were included in this study. Patients were divided into two groups, a hypophosphatemia group and a non-hypophosphatemia group, based on a serum phosphate level of 0.8 mmol/L. Logistic regression was performed to analyze the relationship between hypophosphatemia and mortality. A locally weighted scatterplot smoothing (LOWESS) curve was plotted to show the detailed association between mortality rate and serum phosphate level. A Kaplan–Meier survival curve was drawn to compare the difference in cumulative survival between the two groups.

Results

Hypophosphatemia at admission occurred in 33 patients, with an incidence of 7.6%. The hypophosphatemia group had a significantly higher incidence of respiratory failure (54.5% vs 32.6%, p=0.013) and mortality (57.6% vs 15.2%, p<0.001). Multivariate logistic regression indicated that age (OR=1.059, p<0.001), oxygen saturation (OR=0.733, p<0.001), white blood cells (OR=1.428, p<0.001), lymphocytes (OR=0.075, p<0.001) and hypophosphatemia (OR=3.636, p=0.015) were independently associated with mortality in the included patients. The hypophosphatemia group had significantly shorter survival than the non-hypophosphatemia group (p<0.001).

Conclusion

Hypophosphatemia at admission is associated with increased mortality in COVID-19 patients. More attention and medical care should be given to COVID-19 patients with hypophosphatemia at admission.

Lessons of the month 2: A forgotten cause of transient T-wave inversion

A 19-year-old patient presented with severe chest pain, which is not typical for cardiac angina. However, his smoking history and the strong family history of ischaemic heart disease coupled with evidence of progressive T-wave changes on his electrocardiogram (ECG) caused dilemma in deciding further management. His blood tests were normal apart from hypophosphataemia, and he had two negative troponin results. His arterial blood gases showed respiratory alkalosis. He was given analgesia for a diagnosis of musculoskeletal chest pain and the next morning his ECG, arterial blood gases and phosphate levels all normalised. He had a normal echocardiogram and was reviewed by the cardiologist who diagnosed musculoskeletal chest pain which led to distress and hyperventilation causing hypophosphataemia and transient T-wave inversion. This case is a reminder of an under-recognised physiological phenomenon involving the cardiac conduction during hyperventilation.

Phosphate homeostasis and disorders

Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.

Neurologic complications of electrolyte disturbances and acid-base balance

Electrolyte and acid-base disturbances are common occurrences in daily clinical practice. Although these abnormalities can be readily ascertained from routine laboratory findings, only specific clinical correlates may attest as to their significance. Among a wide phenotypic spectrum, acute electrolyte and acid-base disturbances may affect the peripheral nervous system as arreflexic weakness (hypermagnesemia, hyperkalemia, and hypophosphatemia), the central nervous system as epileptic encephalopathies (hypomagnesemia, dysnatremias, and hypocalcemia), or both as a mixture of encephalopathy and weakness or paresthesias (hypocalcemia, alkalosis). Disabling complications may develop not only when these derangements are overlooked and left untreated (e.g., visual loss from intracranial hypertension in respiratory or metabolic acidosis; quadriplegia with respiratory insufficiency in hypermagnesemia) but also when they are inappropriately managed (e.g., central pontine myelinolisis when rapidly correcting hyponatremia; cardiac arrhythmias when aggressively correcting hypo- or hyperkalemia). Therefore prompt identification of the specific neurometabolic syndromes is critical to correct the causative electrolyte or acid-base disturbances and prevent permanent central or peripheral nervous system injury. This chapter reviews the pathophysiology, clinical investigations, clinical phenotypes, and current management strategies in disorders resulting from alterations in the plasma concentration of sodium, potassium, calcium, magnesium, and phosphorus as well as from acidemia and alkalemia.

Anesthesia for oncogenic osteomalacia--a rare paraneoplastic syndrome

Two patients with a diagnosis of oncogenic osteomalacia are described. This rare disease, characterized by secretion of fibroblast growth factor-23 by the tumor cells, causes myopathy, extreme debilitation and severe osteopathy because of severe hypophosphatemia. Both patients presented with severe bone pain, pathological fractures and proximal muscle weakness. Multiple diagnostic tools had to be utilized to settle the diagnosis of this rare disease. Although supplemental therapy for hypophosphatemia is usually started preoperatively, surgical excision of the causative tumor is the only definite treatment. Surgery is almost always curative; however, there is a lack of discourse in the literature regarding the anesthetic implications for the disease. The complete pathophysiology of the disease, clinical picture, its diagnostic intricacies as well as the salient points in its anesthetic management are discussed in this report.