[Continuous monitoring of O2 saturation in cerebral blood. A guide for the nursing of brain trauma patients in coma].
Manual ventilation is frequently performed by nurses to control increases in intracranial pressure (ICP) or during physiotherapy in head injured comatose patients. The effects of manual ventilation (n = 251) on ICP, cerebral perfusion pressure (CPP) and EEG have been studied in 18 mechanically ventilated patients. A fall in ICP was easily obtained but a fall in arterial blood pressure was often present at the same time. Thus a reduction in CPP resulted in 36% of occasions. Prophylactic boluses of thiopental (n = 67) before noxious stimuli obtained a fall in ICP in 99% of occasions but resulted in a decrease in CPP in 46%. The fall in ICP, due to the decrease in cerebral blood flow (CBF) by hypocapnia or metabolic depression and/or arterial hypotension, may be beneficial in hyperaemic brains but may precipitate cerebral hypoxia in ischaemic lesions. Relevant information about cortical metabolism (CMR) may be obtained from EEG monitoring by Cerebral Function Monitor but, unfortunately, no data about CBF are clinically available. The Authors suggest that the continuous monitoring of jugular bulb oxygen saturation (SjO2) may offer a clinically useful index of CBF adequacy to CMR. Findings from a preliminary study in 5 patients demonstrate that a severe decrease in SjO2 has been frequently caused by manual ventilation, hypothetically related to severe cerebral ischemia. High levels of SjO2 have been induced by endotracheal suction and physiotherapy, probably related to severe hyperemia. As prevention of ischaemic and hyperaemic insults is a major goal of treatment, the A. suggest that these undesirable effects of nursing might be avoided if nurses could take advantage of continuous monitoring of SjO2.
Procaccio
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Reparto di Neurorianimazione, Ospedale Niguarda Ca' Granda, Milano.
Sacchi
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Menasce
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Boselli
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D000293:Adolescent; D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000097:blood / Q000150:complications / Q000451:nursing*; D002648:Child; D003128:Coma / Q000097:blood / Q000209:etiology / Q000451:nursing*; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood*
D010100:Oxygen
Monitoraggio continuo della saturazione di O2 del sangue refluo cerebrale. Una guida del nursing nel traumatizzato cranico in coma.