Confusion with cerebral perfusion pressure in a literature review of current guidelines and survey of clinical practise.

Background: Cerebral perfusion pressure (CPP) is defined as the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP). However, since patients with traumatic brain injury (TBI) are usually treated with head elevation, the recorded CPP values depends on the zero level used for calibration of the arterial blood pressure. Although international guidelines suggest that target values of optimal CPP are within the range of 50 – 70 mmHg in patients with TBI, the calibration of blood pressure, which directly influences CPP, is not described in the guidelines. The aim of this study was to review the literature used to support the CPP recommendations from the Brain Trauma Foundation, and to survey common clinical practice with respect to MAP, CPP targets and head elevation in European centres treating TBI patients. Methods: A review of the literature behind CPP threshold recommendations was performed. Authors were contacted if the publications did not report how MAP or CPP was measured. A short questionnaire related to measurement and treatment targets of MAP and CPP was sent to European neurosurgical centres treating patients with TBI. Results: Assessment methods for CPP measurement were only retrieved from 6 of the 11 studies cited in the TBI guidelines. Routines for assessment of CPP varied between these 6 publications. The 58 neurosurgical centres that answered our survey reported diverging routines on how to measure MAP and target CPP values. Higher CPP threshold were not observed if blood pressure was calibrated at the heart level (p = 0.51). Conclusions: The evidence behind the recommended CPP thresholds shows no consistency on how blood pressure is calibrated and clinical practice for MAP measurements and CPP target values seems to be highly variable. Until a consensus is reached on how to measure CPP, confusion will prevail

Ketamine for prehospital trauma analgesia in a low-resource rural trauma system: a retrospective comparative study of ketamine and opioid analgesia in a ten-year cohort in Iraq

Background Opioid analgesics are used in most trauma systems, and only a few studies report on the use of ketamine for prehospital analgesia. In a low-cost rural trauma system in Iraq paramedics have been using prehospital ketamine analgesia for ten years. This study aims to evaluate the effects of prehospital analgesia on physiologic trauma severity indicators and compare the effect of ketamine and pentazocine on those indicators. Methods The investigation was conducted as a retrospective cohort study with parallel group design. Three subsamples of trauma patients were compared: no analgesia (n = 275), pentazocine analgesia (n = 888), and ketamine analgesia (n = 713). Physiologic severity scores were calculated based on rated values for respiratory rate, blood pressure, and consciousness. The associations between outcomes and explanatory variables were assessed using a generalized linear model. Results Paramedic administration of analgesia was associated with a better physiologic severity score (PSS) outcome (p = 0.01). In the two subsamples receiving analgesia significantly better outcomes were observed for respiration (p 8 ketamine was associated with a significantly better effect on the systolic blood pressure compared to opioid analgesia (p = 0.03). Conclusion Prehospital analgesia for trauma victims improves physiologic severity indicators in a low-resource trauma system. Compared to pentazocine, ketamine was associated with improved blood pressure for patients with serious injuries. In a low-resource setting, ketamine seems to be a good choice for prehospital analgesia in trauma patients