SummaryRigid collars are routinely used to immobilise the cervical spine during early management of trauma victims until spinal injury is excluded. Spinal injuries commonly coexist in patients with severe head injury, and there is still uncertainty as to whether application of a rigid collar may adversely affect intracranial pressure. The aim of this study was to examine this effect by applying rigid collars to patients with traumatic head injury. The results showed a significant rise from the baseline intracranial pressure when the collars were applied (mean rise 4.6 mmHg, p , 0.0001). The mean rise in intracranial pressure was greater in those patients with a baseline intracranial pressure . 15 mmHg compared to those with a baseline intracranial pressure , 15 mmHg (p , 0.05). Since there was no significant change in cardiorespiratory parameters during this time, venous compression in the neck seems a likely explanation for the effect observed. These findings suggest that in head-injured patients, rigid collars should be removed as soon as cervical spine injury has been excluded or, if this is delayed, an alternative method of spinal stabilisation considered.

Posture and baricity during induction of spinal anesthesia with intrathecal drugs are believed to be important in determining spread within the cerebrospinal fluid. In this double-blind prospective study, 150 patients undergoing elective cesarean delivery were randomized to receive a hyperbaric, isobaric, or hypobaric intrathecal solution of 10 mg bupivacaine during spinal anesthesia induced in either the sitting or right lateral position. After an intrathecal injection using a combined-spinal technique patients were placed in the supine wedged position. We determined the densities of the three intrathecal solutions from a previously validated formula and measured using a DMA-450 density meter. Data collection included sensory level, motor block, episodes of hypotension, and ephedrine use. Statistical analysis included analysis of variance and Cuzick's trend. In the lateral position, baricity had no effect on the spread of sensory levels for bupivacaine compared to the sitting position, where there was a statistically significant difference in spread with the hypobaric solution producing higher levels of analgesia than the hyperbaric solution (P = 0.002). However, the overall differences in maximal spread only differed by one dermatome, with the hyperbaric solution achieving a median maximum sensory level to T3 compared with T2 for the isobaric and hypobaric solutions. Motor block was significantly (P = 0.029) reduced with increasing baricity and this trend was significant (P = 0.033) for the lateral position only. Hypotension incidence and ephedrine use increased with decreasing baricity (P = 0.003 and 0.004 respectively), with the hypobaric sitting group having the most frequent incidence of hypotension (76%) as well as cervical blocks (24%; P = 0.032).

Under the conditions of this study, the addition of intrathecal fentanyl 5 microg offers a similar significant bupivacaine dose-sparing effect as 15 and 25 microg. Analgesia in the first stage of labor can be achieved using lower doses of fentanyl, resulting in less pruritus but with a shortening of duration of action.

We conclude that impairment of primary hemostatic function with increasing severity of preeclampsia was recorded by the PFA-100 but not the TEG.