Proper Partial Pressure of Arterial Oxygen for Patients with Traumatic Brain Injury.

BACKGROUND The partial pressure of arterial oxygen (PaO2) is critical to the outcome of patients with traumatic brain injury (TBI). However, it is not clear what range of PaO2 should be maintained to improve patient outcome. The aim of this study was to explore the PaO2 value needed in the acute phase of TBI and provide new evidence for clinical practice. MATERIAL AND METHODS A total of 153 patients with TBI were enrolled retrospectively. Univariate and multivariate logistic regression analyses were conducted on sex, Glasgow Coma Scale (GCS) score on admission, PaO2 within 6 h of admission, oxygenation index, and other factors. The Glasgow Outcome Score (GOS) of the patient at discharge was used as an indicator of outcome. The good outcome group had GOS ≥4, and the poor outcome group had GOS <4. RESULTS The 153 patients were divided into a good outcome group (n=62) and poor outcome group (n=91). There was a significant difference in sex, admission GCS, surgery, airway status, PaO2, and oxygen index within 6 h of admission between the 2 groups. Logistic regression analysis showed that PaO2 <60 mmHg, male sex, and admission GCS score of 3 to 12 were independent risk factors for a poor outcome. CONCLUSIONS Patients with TBI having PaO2 <60 mmHg within 6 h after admission were more likely to have poor outcomes. The upper limit value of PaO2 that affects the outcome of TBI in patients has not been found.

[The influence of positive end-expiratory pressure on central venous pressure in patients with severe craniocerebral injury].

OBJECTIVE: To observe the impact of positive end-expiratory pressure (PEEP) on central venous pressure (CVP) in mechanically ventilated patients with severe craniocerebral injury. METHODS: A prospective, interventional, self-control study was conducted. Thirty severe craniocerebral injury patients with central respiratory failure were enrolled. The changes in CVP, mean arterial pressure (MAP), heart rate (HR) and pulse oxygen saturation [SpO2] were monitored at different PEEP levels [0, 3, 6, 9, 12, 15 cm H2O; 1 cm H2O=0.098 kPa] during mechanical ventilation and after weaning of mechanical ventilation. The influences of PEEP and its discontinuance on haemodynamics and oxygenation were analyzed. RESULTS: The values of CVP [cm H2O] were increased when PEEP increased (from 7.9±3.1 to 13.1±3.7), a linear correlation was found (R=0.509, P=0.000), and linear regression equation was CVP [cm H2O]=7.774+0.368×PEEP [cm H2O]; CVP was elevated about 0.368 cm H2O when PEEP increased 1 cm H2O. CVP values significantly decreased during discontinuance of mechanical ventilation, as compared to those measured at different PEEP levels during mechanical ventilation (F=24.429, P=0.000). The values of MAP, HR and SpO2 showed no significant change with increase of PEEP levels [MAP (mm Hg, 1 mm Hg=0.133 kPa): from 81.6±10.4 to 85.6±10.6; HR (beats per minute): from 79.9±13.5 to 88.1±15.4; SpO2: from 0.968±0.036 to 0.975±0.033, all P>0.05] in mechanically ventilated patients, but discontinuance of mechanical ventilation could significantly increase the levels of MAP and HR (95.3±8.4 and 94.9±10.3, respectively) and lower SpO2 levels (0.928±0.036, all P=0.000). CONCLUSIONS: CVP values were overestimated during an increase in PEEP in mechanically ventilated patients with severe craniocerebral injury. CVP was increased about 0.368 cm H2O following an increase of PEEP of 1 cm H2O, whereas the values of MAP, HR and SpO2 showed no significant change with increase in PEEP levels. This study could offer a theoretical base in the correct assessment of CVP values at different PEEP levels without discontinuation of mechanical ventilation.