Preoperative carbon dioxide reactivity studies do not predict the hemodynamic changes seen during carotid endarterectomy after internal carotid artery clamping.

BACKGROUND AND PURPOSE.: A preoperative warning of progressive cerebral ischemia during surgery may be of use in planning carotid endarterectomy (CE). We have set out to determine whether preoperative cerebrovascular reactivity studies predict the late hemodynamic changes detected during the procedure. PATIENTS AND METHODS.: Sixty-seven patients awaiting CE for high-grade carotid stenosis underwent preoperative cerebral CO(2) reactivity assessment using standard transcranial Doppler (TCD) methods. During subsequent surgery, hemodynamic changes were monitored with TCD, near-infrared spectroscopy, and a cerebral function monitor. Signals of mean MCA flow velocity (FV) and of cerebral oxyhemoglobin and deoxyhemoglobin concentration were recorded continuously, and the mean values were measured at 5, 10, and 15 minutes after internal carotid clamping. For each variable, the maximum signal change was measured 5 minutes after clamp application (Max(5)), and in addition the spontaneous hemodynamic recovery over the next 10 minutes (I(rec)) was calculated. Scatterplots of Max(5) and I(rec) against preoperative CO(2) reactivity indices (ipsilateral, bihemispheric mean, and interhemispheric assymmetry) were generated for correlative analysis. RESULTS.: The Max(5) for oxyhemoglobin and deoxyhemoglobin were inversely related (r=-.302, P=.015). There was no relationship between ipsilateral preoperative CO(2) reactivity index and Max(5) for any intraoperative variable measured. In addition, the reactivity did not predict the hemodynamic recovery (I(rec)) observed during clamp application. However, the interhemispheric asymmetry did show a modest inverse correlation to Max(5) FV (r=-.256, P=.046). CONCLUSION.: Preoperative TCD cerebral CO(2) reactivity cannot be used clinically to predict the intraoperative hemodynamic changes seen during CE.     

The management of midline transcranial nasal dermoid sinus cysts.

The most common congenital midline nasal masses are nasal dermoid sinus cysts (NDSC) [Hughes GB, Sharpino G, Hunt W, Tucker HM. Management of the congenital midline nasal mass--a review. Head Neck Surg 1980;2:222-33.]. Their clinical importance hinges on their potential to communicate with the central nervous system. Preoperative diagnosis of an intracranial extension allows for referral to a craniofacial team with the appropriate skills and experience for a transcranial approach. All patients with a NDSC require imaging with high resolution multiplanar MRI scans and complimentary fine cut CT scan to reveal the anatomical extent of the tract and its relationship to the anterior cranial fossa. A single-stage craniofacial approach to resection of midline NDSC extending to the anterior cranial base is effective with minimal morbidity [Yavuzer R, Bier U, Jackson IT. Be careful: it might be a nasal dermoid cyst. Plast Reconstr Surg 1999;103:2082-3; Denoyelle F, Ducroz V, Roger G, Garabedian EN. Nasal dermoid sinus cysts in children. Laryngoscope 1997;107:795-800; Rohrich RJ, Lowe JB, Schwartz MR. The role of open rhinoplasty in the management of nasal dermoid cysts. Plast Reconstr Surg 1999;104:2163-70; Rahbar R, Shah P, Mulliken JB, et al. The presentation and management of nasal dermoid-a 30-year experience. Arch Otolaryngol Head Neck Surg 2003;129:464-71; Posnick JC, Bortoluzzi P, Armstrong DC, Drake JM. Intracranial nasal dermoid sinus cysts: computed tomographic scan findings and surgical results. Plast Reconstr Surg 1994;93:745-54 [discussion 755-56]; Bartlett SP, Lin KY, Grossman R, Kratowitz J. The surgical management of orbitofacial dermoids in the pediatric patient. Plast Reconstr Surg 1993;91:1208-15.]. The cyst and tract are accessed through a combination of a nasal and transcranial approach. This allows visualisation and dissection of the tract with only a small incision on the nasal dorsum to include the cutaneous punctum when present. Transnasal endoscopic techniques have been advocated where the dermoid is located within the nasal cavity and there is little or no cutaneous involvement [Weiss DD, Robson CD, Mulliken JB. Transnasal endoscopic excision of midline nasal dermoid from the anterior cranial base. Plast Reconstr Surg 1998;101:2119-23.]. We present a review of five cases referred to our unit between 1999 and 2004 with a diagnosis of a midline nasal dermoid sinus cyst and radiological evidence of intracranial communication. All cases had a communication with the anterior cranial fossa diagnosed preoperatively and were treated surgically with a craniofacial approach. An intracranial extension was identified at operation in each case and this was confirmed on histopathology. The only significant complication resulted from an early postoperative infection, requiring re-operation. There were no recurrences and acceptable aesthetic outcomes have been observed in all cases.     

Measurement of transepidermal water loss in Tanzanian cot-nursed neonates and its relation to postnatal weight loss

In healthy cot-nursed Tanzanian neonates ( n = 92, gestation 26–42 weeks) measurements of transepidermal water loss (TEWL) and weight change were performed during the first 24 h after birth at an average ambient humidity of 70% and an environmental temperature of 32°C. Urine production on day 1 (ml/kg per 24h) was documented for a subgroup of 13 preterm and 8 term infants. In a limited group of preterm infants ( n = 5) TEWL measurements, weight and 24 h urine volume measurements were repeated daily for 7 days. Maximum weight loss was determined in 7 preterm (gestational age 30–36 weeks) and 6 term infants. TEWL was estimated by measuring the evaporation rate at three sites of the body using the water vapour pressure gradient method. On day 1, TEWL was highest in the most preterm infants, whereas TEWL and urine production were higher in large for gestational age infants as compared to appropriate for gestational age (AGA) infants of the same gestational age (31–36 weeks). For the whole group, weight loss on day 1 was correlated with TEWL ( r = 0.49, p <0.05). At follow-up TEWL in preterm infants remained almost constant during the first 4 days and decreased after the fourth day, at which time weight gain commenced. Preterm AGA infants (gestational age 24–37 weeks) showed a mean postnatal weight loss of 4.4% of the birth weight, while in term infants this loss was only 2.6%. A reduced postnatal weight loss as compared to Caucasian infants may be explained by a lower water loss during the first days after birth, through both skin evaporation and urine excretion.     

Effect of fibrinogen fragments D and E on the adhesive properties of human granulocytes to venous endothelial cells.

In hyperfibrinolytic conditions, e.g. in disseminated intravascular coagulation or the adult respiratory distress syndrome, high levels of fibrinogen degradation products (FDPs) D and E are found in human plasma. This study investigates the influence of these fragments on cell attachment of human granulocytes in vitro. While leaving unaffected the adhesion of human umbilical vein endothelial cells (HUVEC) on gelatine-coated glass, both FDP fragments at 50 micrograms/ml inhibited granulocyte attachment to glass as well as to HUVEC monolayers. At the same concentration, the fragments diminished the superoxide release of stimulated granulocytes. These results suggest a modulatory role of pathologically elevated FDPs on the granulocyte function cascade.