[Operative treatment of femoral head fractures through an anterior minimally invasive incision]. / Osteosynthese der Pipkin-II-Fraktur über den minimalinvasiven anterioren Zugang.

Fractures of the femoral head rarely occur and are often combined with dislocation of the hip joint. A separate classification of the femoral head fracture was described in 1957 by Pipkin. The operative treatment depends on the type of injury and requires extensive knowledge of the various operative approaches. We report on a 40-year-old female patient with Pipkin II fracture and operative treatment of the injury through an anterior minimally invasive incision. We present a review of the literature, evaluate the type of fractures, the kind of approaches and treatment and the long-term results. The dislocation of the hip should be treated by prompt closed reduction followed by traction and immobilization. Open reduction and internal fixation of Pipkin fractures depends on the presence of an obstructive fragment, an inability to obtain and maintain reduction of either the dislocation of the fracture or both and comminution of the fracture bone. When closed methods have failed operation is indicated. The operative treatment may include the excision of small fragments, the internal fixation with bioabsorbable screws, Herbert screws and the internal fixation of femoral neck fractures and acetabular fractures. In some cases salvage procedures like endoprotheses are necessary.

Respiratory mechanics during xenon anesthesia in pigs: comparison with nitrous oxide.

BACKGROUND: Because of its high density and viscosity, xenon (Xe) may influence respiratory mechanics when used as an inhaled anesthetic. Therefore the authors studied respiratory mechanics during xenon and nitrous oxide (N2O) anesthesia before and during methacholine-induced bronchoconstriction. METHODS: Sixteen pentobarbital-anesthetized pigs initially were ventilated with 70% nitrogen-oxygen. Then they were randomly assigned to a test period of ventilation with either 70% xenon-oxygen or 70% N2O-oxygen (n = 8 for each group). Nitrogen-oxygen ventilation was then resumed. Tidal volume and inspiratory flow rate were set equally throughout the study. During each condition the authors measured peak and mean airway pressure (Pmax and Pmean) and airway resistance (R(aw)) by the end-inspiratory occlusion technique. This sequence was then repeated during a methacholine infusion. RESULTS: Both before and during methacholine airway resistance was significantly higher with xenon-oxygen (4.0 +/- 1.7 and 10.9 +/- 3.8 cm H2O x s(-1) x 1(-1), mean +/- SD) when compared to nitrogen-oxygen (2.6 +/- 1.1 and 5.8 +/- 1.4 cm H2O x s(-1) x l(-1), P < 0.01) and N2O-oxygen (2.9 +/- 0.8 and 7.0 +/- 1.9, P < 0.01). Pmax and Pmean did not differ before bronchoconstriction, regardless of the inspired gas mixture. During bronchoconstriction Pmax and Pmean both were significantly higher with xenon-oxygen (Pmax, 33.1 +/- 5.5 and Pmean, 11.9 +/- 1.6 cm H2O) when compared to N2O-oxygen (28.4 +/- 5.7 and 9.5 +/- 1.6 cm H2O, P < 0.01) and nitrogen-oxygen (28.0 +/- 4.4 and 10.6 +/- 1.3 cm H2O, P < 0.01). CONCLUSIONS: Airway pressure and resistance are increased during xenon anesthesia. This response is moderate and not likely to assume major importance for the general use of xenon in anesthesia.

Continuous arterial P(O2) and P(CO2) measurements in swine during nitrous oxide and xenon elimination: prevention of diffusion hypoxia.

BACKGROUND: During nitrous oxide (N2O) elimination, arterial oxygen tension (PaO2) decreases because of the phenomenon commonly called diffusive hypoxia. The authors questioned whether similar effects occur during xenon elimination. METHODS: Nineteen anesthetized and paralyzed pigs were mechanically ventilated randomly for 30 min using inspiratory gas mixtures of 30% oxygen and either 70% N2O or xenon. The inspiratory gas was replaced by a mixture of 70% nitrogen and 30% oxygen. PaO2 and carbon dioxide tensions were recorded continuously using an indwelling arterial sensor. RESULTS: The PaO2 decreased from 119+/-10 mm Hg to 102+/-12 mm Hg (mean+/-SD) during N2O washout (P<0.01) and from 116+/-9 mm Hg to 110+/-8 mm Hg during xenon elimination (P<0.01), with a significant difference (P<0.01) between baseline and minimum PaO2 values (deltaPaO2, 17+/-6 mm Hg during N2O washout and 6+/-3 mm Hg during xenon washout). The PaCO2 value also decreased (from 39.3+/-6.3 mm Hg to 37.6+/-5.8 mm Hg) during N2O washout (P<0.01) and during xenon elimination (from 35.4+/-1.6 mm Hg to 34.9+/-1.6 mm Hg; P< 0.01). The deltaPaCO2 was 1.7+/-0.9 mm Hg in the N2O group and 0.5+/-0.3 mm Hg in the xenon group (P<0.01). CONCLUSION: Diffusive hypoxia is unlikely to occur during recovery from xenon anesthesia, probably because of the low blood solubility of this gas.