The acid-base status of seriously wounded combat casualties. I. Before treatment

[Control of bleeding in the military environment]

One of the basics of military medicine is the control of haemorrhagic shock. Haemorrhage is the first cause of preventable death in combat, with the adequate control of bleeding being considered as fundamental to estimate the survival of the combatant as well as therapeutic support aimed at minimising blood loss being a challenge within military health logistics. The aim of this work is to review the medical and logistics advances in the treatment of bleeding in the military environment and combat during the latest conflicts, and to describe what is the current contribution of the Spanish Armed Forces and to profile future lines of investigation.

Prognostic significance of ventricular CSF lactic acidosis in severe head injury

Brain-tissue acidosis inferred by cerebrospinal fluid (CSF) lactic acidosis is considered to play an important role in the clinical course of severe head injury. Ventricular CSF lactate concentration was studied in 19 patients during the first 5 days after severe head injury. All patients were intubated, paralyzed, and artificially ventilated so that PaCO2 was kept at 33.2 +/- 5.0 mm Hg and PaO2 at 122 +/- 18 mm Hg (mean +/- standard deviation). The mean Glasgow Coma Scale score on admission was 5.73 +/- 2.42. The first CSF sample was drawn within 18 hours after head injury. Over the first 4 days postinjury, patients with a poor outcome had significantly higher ventricular CSF lactate levels than did those with moderate disabilities or a good outcome. Patients showing favorable outcome had a significant decrease in ventricular CSF lactate levels 48 hours after injury. This decrease was not observed in patients with a poor outcome. Increased ventricular CSF lactate concentration was also reliably associated with increased intracranial pressure (ICP). Ventricular CSF lactate levels did not correlate with the magnitude of intraventricular bleeding. Arterial and jugular venous blood lactate levels, although high after head injury, were usually lower than the levels in the ventricular CSF and reached a normal range by the 3rd day following head trauma. At that time, the ventricular CSF lactate concentration was still above normal in patients with a poor outcome but had decreased to normal in patients with moderate disabilities or a good outcome. Ventricular CSF pH did not generally correlate with the ventricular CSF lactate concentration in patients under controlled ventilation; however, in a few patients close to death or with ventricular infection, a correlation was noted. Ventricular CSF lactate levels were not related to cerebral blood flow. In this study, profiles of ventricular CSF lactate concentration are defined in relation to the patients' clinical course and outcome. High ventricular CSF lactate concentration is present within 18 hours after severe head injury. Its decrease to normal in the following 48 hours is a reliable sign of clinical improvement; however, ventricular CSF lactate levels that are persistently high or that increase over time indicate the patient's deterioration. Serial assessment of ventricular CSF for acid-base status and metabolites in head-injured patients with a ventricular catheter already placed for ICP monitoring is useful in the evaluation of prognosis and clinical course.

Anesthesia in the Yom Kippur war

The role of the anesthetist in the treatment of battle casualties is discussed in the light of personal experience in a field hospital and in the rear during the Yom Kippur War of October 1973. Resuscitation and intensive care both before and after evacuation play an important part in reducing mortality, and the importance of providing adequate facilities for these functions in the battle area as well as at the base is emphasized.

Biochemical quantification of blunt injuries

During eight post-traumatic days, the blood loss and severity of trauma were correlated with the blood levels of lactate, creatinine and catecholamines in 45 patients with multiple blunt injuries. During two days these biochemical indicators correlated with the extent of thoracoabdominal, pelvic and cerebral injuries. In the critically injured patients all three parameters were elevated throughout the observation period. No correlations were observed between plasma catecholamines and lower limb injuries, which seems to make the importance of catecholamines for predicting the onset of fat embolism syndrome less useful.

Acid-base balance and arterial and CSF lactate levels following human head injury

✓ Sequential arterial and cerebrospinal fluid (CSF) lactate, pH, pCO2, HCO3−, and pO2 levels were determined for 4 days in 17 patients immediately following uncomplicated head injury. Lactate was initially markedly elevated in both fluids and decreased by the third day after injury. There was mild arterial metabolic acidosis and respiratory alkalosis on admission; the alkalosis continued. Arterial pO2 was below normal at all times. The CSF showed a normal pO2, and metabolic acidosis related to lactate accumulation. Blood and CSF pCO2 and HCO3− levels equilibrated well, probably because of the time factor; CSF and arterial pO2 levels were not significantly related. The clinical implications of CSF lacticacidosis after head injury are discussed.

Regulation of ventilation during hemorrhage and its alterations in response to CO 2

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