The Value of Myocardium and Kidney Histopathological and Immunohistochemical Findings in Accidental Hypothermia-Related Fatalities

Effects of intraoperative body temperature, blood pressure, cerebral tissue oxygenation, and anesthesia type on postoperative cognitive functions in geriatric arthroplasty surgery for hip fracture

OBJECTIVES

This study aimed to explore the effects of cerebral oxygenation, body temperature, hemodynamic changes, and anesthesia type on postoperative cognitive dysfunction (POCD) in geriatric patients undergoing hip fracture surgery.

PATIENTS AND METHODS

One hundred five elderly patients (59 males, 46 females; mean age: 76.7±8.8 years; range, 65 to 95 years) who were scheduled for hip fracture surgery under general or spinal anesthesia between March 2021 and March 2023 were enrolled in the prospective observational study. The cognitive functions were evaluated using the Mini-Mental State Examination (MMSE). Postoperative MMSE values <24 were considered indicative of POCD. Cerebral oxygenation was evaluated before and during the operation using near-infrared spectroscopy (NIRS), and body temperature was measured using a tympanic thermometer, with values <36℃ considered hypothermia. The relationship between decreases in blood pressure ≥30% and POCD was investigated. The relationship between decreases in NIRS of 25% and POCD was also investigated.

RESULTS

Postoperative cognitive dysfunction was observed in 29 (27.25%) of the 105 patients. The MMSE value was 24 in 67.06% of 29 patients, and all these patients developed POCD. The incidence of POCD in patients with a preoperative MMSE1 score of 30 was 12.30% (p=0.001). No relationship was identified between MMSE changes and anesthesia type, hypotension, and decreases in the NIRS (p=0.439, p=0.399). Hypothermia was found to be significantly related to POCD (p=0.013). The degree of hypothermia decreased the postoperative MMSE value at different rates. A 1°C body temperature decrease caused a 16.7%, 44.4%, and 50% decrease in MMSE scores of one, one, and two patients, respectively.

CONCLUSION

Hypothermia was found to be significantly related to POCD. The same degree of hypothermia caused different MMSE changes. Since the number of patients with POCD was very low, the effect of amounts of body temperature changes on clinically significant MMSE changes could not be supported by logistic regression. The preoperative MMSE values, MMSE change rates, and age were found to be effective in POCD. Maintaining the body temperature throughout the operation will ensure the preservation of postoperative cognitive functions.

Advanced Diagnostic Tools in Hypothermia-Related Fatalities-A Pathological Perspective

BACKGROUND AND OBJECTIVES

Although classical gross features are known in hypothermia victims, they lack specific diagnosis features. The aim of our study was to reveal specific brain and lung pathological features in a group of hypothermia-related fatalities.

MATERIALS AND METHODS

The study group comprised 107 cases from our files associated with hypothermia. Routine hematoxylin-eosin (H&E) staining and postmortem immunohistochemistry were performed.

RESULTS

The microscopic cerebral exam revealed diffuse perineuronal and perivascular edema, gliosis, mononuclear cell infiltration, acute brain injuries, focal neuronal ischemia, lacunar infarction, and variable hemorrhages. Variable alveolar edema, pulmonary emphysema, intra-alveolar and/or pleural hemorrhage, and bronchopneumonia, as well as other pre-existing lesions, were identified in lung tissue samples. Glial cells displayed S100β expression, while neurons showed moderate Hsp70 immunopositivity. Alveolar basal membranes exhibited diffuse ICAM-1 positive expression, while ICAM-1 and AQP-1 positivity was observed in the alveolar septum vascular endothelium. Statistical analysis revealed a significant correlation between S100β and Hps70 immunoexpression and cerebral pathological features, between ICAM-1 immunoexpression and alveolar edema and pulmonary emphysema, and between AQP-1 immunoexpression and pulmonary emphysema.

CONCLUSIONS

Our results add supplementary data to brain and lung pathological findings in hypothermia-related fatalities, with potential therapeutic value in hypothermia patients.

Hypothermia: Beyond the Narrative Review-The Point of View of Emergency Physicians and Medico-Legal Considerations

Hypothermia is a widespread condition all over the world, with a high risk of mortality in pre-hospital and in-hospital settings when it is not promptly and adequately treated. In this review, we aim to describe the main specificities of the diagnosis and treatment of hypothermia through consideration of the physiological changes that occur in hypothermic patients. Hypothermia can occur due to unfavorable environmental conditions as well as internal causes, such as pathological states that result in reduced heat production, increased heat loss or ineffectiveness of the thermal regulation system. The consequences of hypothermia affect several systems in the body-the cardiovascular system, the central and peripheral nervous systems, the respiratory system, the endocrine system and the gastrointestinal system-but also kidney function, electrolyte balance and coagulation. Once hypothermia is recognized, prompt treatment, focused on restoring body temperature and supporting vital functions, is fundamental in order to avert preventable death. It is important to also denote the fact that CPR has specificities related to the unique profile of hypothermic patients.