Risk factors for postoperative eye pain in patients with non-painful eye disease undergoing pars plana vitrectomy: the VItrectomy Pain (VIP) study.

BACKGROUND: Pars plana vitrectomy (PPV), a surgical procedure used to treat different ophthalmic pathologies, could be associated with moderate to severe eye pain. The aim of the present study was to evaluate the incidence of postoperative eye pain and its risk factors following PPV in a selected population of patients with non-painful eye disease, receiving regional anesthesia and moderate sedation with benzodiazepines, without use of narcotics. METHODS: Single-center, prospective observational cohort study. We recorded the presence of pain at operating room discharge, at 6 and 24 hours, using the numeric rating scale (NRS). We recorded also age, sex, ethnic origin, American Society of Anaesthesia physical status (ASA PS) classification, Charlson Comorbidity Index, the etiology of the vitreoretinal pathology, length of surgery, and type of surgical procedure performed. RESULTS: Eye pain (NRS>3) was present in three patients (0.7%) at operating room discharge, 59 (13.2%) at six and 65 (14.6%) at 24 hours after surgery. LASSO logistic regression analysis identified age, ASA PS, race, along with tamponade as independent risk factors for eye pain at six hours. Scleral buckling was selected for eye pain at 24 hrs. CONCLUSIONS: A protocol for pain control after PPV should be considered, especially in younger, non-Caucasian people, and patients with high ASA PS grade. Moreover, attention must be paid when additional surgical procedures are requested, restricting them to selected patients, and using the appropriate agent for intraocular tamponade.

Cerebral blood flow thresholds for cerebral ischemia in traumatic brain injury. A systematic review.

BACKGROUND: Reduction of cerebral blood flow plays a crucial role in causing posttraumatic cerebral ischemia. However, the methodologic adequacy of studies from which currently used cerebral blood flow thresholds in traumatic brain injury have been derived has not been evaluated. OBJECTIVE: To systematically evaluate the evidence available on cerebral blood flow thresholds and its methodologic adequacy in adults with traumatic brain injury. METHODS: Included were primary studies on adults with traumatic brain injury in which cerebral blood flow thresholds were evaluated and reported, and follow-up brain computed tomography or magnetic resonance imaging was used as the gold standard for diagnosing the finally infarcted area. RESULTS: Among the 53 diagnostic studies identified, 31 did not report any threshold value, whereas 20 studies used thresholds derived from the literature, mainly animal or clinical studies on ischemic stroke. One study measured cerebral blood flow thresholds, but did not use accepted neuroradiological criteria for the diagnosis of posttraumatic cerebral ischemia. The remaining study fulfilled all methodologic inclusion criteria, but was restricted to 14 patients with severe traumatic brain injury and cerebral contusion. This study proposed a cerebral blood flow threshold of 15 mL/100 mL/min, with sensitivity and specificity of 43% and 95%, respectively. CONCLUSIONS: Cerebral blood flow thresholds for the diagnosis of posttraumatic cerebral ischemia are based on weak evidence, and cannot be recommended.

Cerebral blood flow threshold of ischemic penumbra and infarct core in acute ischemic stroke: a systematic review.

BACKGROUND AND PURPOSE: Cerebral blood flow (CBF) reduction below critical thresholds discriminates between irreversible infarct core, penumbra, and benign oligemia (penumbra that recovers spontaneously). Thresholds are based on animal studies, and their diagnostic accuracy in humans has never been established. The purpose of this study was to assess the evidence available on CBF thresholds for infarct core and penumbra in adult stroke patients. METHODS: Electronic database searching using Medline, Embase and the Cochrane Library, crosschecking of references, and contact with experts and authors of primary studies was used. Studies on adult stroke patients were included if they compared CBF measurements with a diagnostic gold standard (follow-up brain CT/MRI), and reported CBF thresholds. Two reviewers independently extracted the data and assessed study quality. RESULTS: A meta-analysis could not be carried out because of insufficient data. The optimal reported CBF thresholds varied widely, from 14.1 to 35.0 and from 4.8 to 8.4 mL/100 g per minute for penumbra and infarct core, respectively. CONCLUSIONS: The use of CBF thresholds in commercial software for imaging methods cannot be recommended without further evaluation.