The Association Between Hypophosphatemia and Lactic Acidosis After Cardiac Surgery With Cardiopulmonary Bypass: A Retrospective Cohort Study.

OBJECTIVES: The clinical significance of hypophosphatemia in cardiac surgery has not been investigated extensively. The aim of this study was to evaluate the association of postoperative hypophosphatemia and lactic acidosis in cardiac surgery patients at the time of intensive care unit (ICU) admission. DESIGN: A retrospective cohort study. SETTING: At a single academic center. PARTICIPANTS: Patients who underwent nontransplant cardiac surgery with cardiopulmonary bypass between August 2009 and December 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Serum phosphate and lactate levels were measured upon ICU admission in patients undergoing nontransplant cardiac surgery with cardiopulmonary bypass. There were 681 patients in the low-phosphate (<2.5 mg/dL) group and 2,579 patients in the normal phosphate group (2.5-4.5 mg/dL). A higher proportion of patients in the low phosphate group (26%; 179 of 681; 95% CI: 23-30) had severe lactic acidosis compared to patients in the normal phosphate group (16%; 417 of 2,579; 95% CI: 15-18). In an unadjusted logistic regression model, patients in the low phosphate group had 1.9-times the odds of having severe lactic acidosis (serum lactate ≥4.0 mmol/L) when compared to patients in the normal phosphate group (95% CI: 1.5-2.3), and still 1.4-times the odds (95% CI: 1.1-1.7) after adjusting for several possible confounders. CONCLUSIONS: Hypophosphatemia is associated with lactic acidosis in the immediate postoperative period in cardiac surgery patients. Future studies will need to investigate it as a potential treatment target for lactic acidosis.

Left Ventricular Function in the Initial Period After Severe Traumatic Brain Injury in Swine.

BACKGROUND: Cardiac dysfunction is common in the days after severe traumatic brain injury (TBI) and may contribute to hypotension episodes, leading to worse outcomes. Little is known about cardiac function in the minutes and hours immediately following TBI. By using fluid percussion TBI in a swine model, we aimed to characterize the immediate post injury cardiac function. METHODS: Intubated, anesthetized immature (25.8 ± 1.5 kg) female swine were subjected to severe fluid percussion TBI (4.2 ± 0.2 atm). Beginning at 45 min, simulating hospital arrival, all animals were resuscitated with normal saline (NS), mannitol, and phenylephrine as needed to maintain a cerebral perfusion pressure more than 60 mm Hg and intracranial pressure (ICP) less than 20 mm Hg. Primary outcomes of cardiac function were cardiac output measured by thermodilution and transesophageal echo measurements of cardiac function recorded at prespecified time points and tested for trends over time using linear regression with spline at the time of resuscitation onset. Secondary outcomes included hemodynamic measurements, ICP, and cerebral perfusion pressure. RESULTS: Eighteen animals were included. Post-TBI hemodynamic changes demonstrated an early decrease in mean arterial pressure and cerebral perfusion pressure with a corresponding increase in heart rate and ICP. Immediately after injury, there was a significant decrease in both left atrial area and tissue Doppler imaging e' of the LV lateral wall. In addition, there was a simultaneous increase in LV end diastolic diameter and increase in E/e' ratio of the lateral mitral annulus. All other transesophageal echo measurements demonstrated no significant changes throughout the duration of the experiment. CONCLUSIONS: Traumatic brain injury is associated with cardiac dysfunction and increased mortality, however there is still a limited understanding of the hemodynamic and echocardiographic response associated with TBI. In this study we demonstrate the hemodynamic and echocardiographic changes in the early stages of TBI in swine. The authors hope that these results may help better understanding on the management of patients with severe head injury.

Giovanni Battista Morgagni (1682-1771): his anatomic majesty's contributions to the neurosciences.

INTRODUCTION: Giovanni Battista Morgagni is considered the Father of Pathology and contributed much to our early understanding of neuropathology. For example, he introduced the concept that diagnosis, prognosis, and treatment of disease must be based on an exact understanding of the pathologic changes in anatomic structures. Additionally, he contributed to what would become the discipline of neurosurgery and, for example, performed trepanation for head trauma. CONCLUSIONS: It is the contributions of such early pioneers as Morgagni that our current understanding of the neurosciences is based.

Anesthetic Considerations of Sporadic Inclusion Body Myositis in an Elderly Man With Orthopedic Trauma.

INTRODUCTION: Sporadic inclusion body myositis (IBM) is an inflammatory myopathy characterized by progressive asymmetric extremity weakness, oropharyngeal dysphagia, and the potential for exaggerated sensitivity to neuromuscular blockers and respiratory compromise. The authors describe their management of a patient with IBM undergoing urgent orthopedic surgery. CASE PRESENTATION: An 81-year-old man with IBM suffered a left intertrochanteric femoral fracture after falling down stairs. His IBM caused progressive left proximal lower extremity, bilateral distal upper extremity weakness (left > right), and oropharyngeal dysphagia (solid food, pills). He denied dyspnea, exercise intolerance, and a history of aspiration. Because respiratory insufficiency resulting from diaphragmatic dysfunction and prolonged duration of action of neuromuscular blockers may occur in IBM, the authors avoided using a neuromuscular blocker. After applying cricoid pressure, anesthesia was induced using intravenous lidocaine, propofol, remifentanil followed by manual ventilation with inhaled sevoflurane in oxygen. Endotracheal intubation was accomplished without difficulty; anesthesia was then maintained using remifentanil and sevoflurane. The fracture was repaired with a trochanteric femoral nail. The patient was extubated without difficulty and made an uneventful recovery. CONCLUSIONS: In summary, there is a lack of consensus about the use of neuromuscular blockers in patients with IBM. The authors avoided these drugs and were able to easily secure the patient's airway and maintain adequate muscle relaxation using a balanced sevoflurane-remifentanil anesthetic. Clinical trials are necessary to define the pharmacology of neuromuscular blockers in patients with IBM and determine whether use of these drugs contributes to postoperative respiratory insufficiency in these vulnerable patients.

The nervus intermedius: a review of its anatomy, function, pathology, and role in neurosurgery.

BACKGROUND: Geniculate neuralgia, although uncommon, can be a debilitating pathology. Unfortunately, a thorough review of this pain syndrome and the clinical anatomy, function, and pathology of its most commonly associated nerve, the nervus intermedius, is lacking in the literature. Therefore, the present study aimed to further elucidate the diagnosis of this pain syndrome and its surgical treatment based on a review of the literature. METHODS: Using standard search engines, the literature was evaluated for germane reports regarding the nervus intermedius and associated pathology. A summary of this body of literature is presented. RESULTS: Since 1968, only approximately 50 peer-reviewed reports have been published regarding the nervus intermedius. Most of these are single-case reports and in reference to geniculate neuralgia. No report was a review of the literature. CONCLUSIONS: Neuralgia involving the nervus intermedius is uncommon, but when present, can be life altering. Microvascular decompression may be effective as a treatment. Along its cisternal course, the nerve may be difficult to distinguish from the facial nerve. Based on case reports and small series, long-term pain control can be seen after nerve sectioning or microvascular decompression, but no prospective studies exist. Such studies are now necessary to shed light on the efficacy of surgical treatment of nervus intermedius neuralgia.