Improved microdetermination for diphenylhydantoin in blood by UV spectrophotometry

Closed-suction drainage in thoracolumbar spinal surgery-clinical routine without evidence? a systematic review

PURPOSE

The considered benefit of surgical drain use after spinal surgery is to prevent local accumulation of a haematoma by decompressing the closed space in the approach of the surgical site. In this context, the aim of the present systematic review was to prove the benefit of the routine use of closed-suction drains.

METHODS

We conducted a comprehensive systematic review of the literature according to the Preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist and algorithm.

RESULTS

Following the literature search, 401 potentially eligible investigations were identified. Eventually, a total of 24 studies with 8579 participants were included. Negative suction drainage led to a significantly higher volume of drainage fluid. Drainage duration longer than 72 h may be associated with a higher incidence of Surgical side infections (SSI); however, accompanying antibiotic treatment is unnecessary. Regarding postoperative haematoma and neurological complications, no evidence exists concerning their prevention. Hospital stay length and related costs may be elevated in patients with drainage but appear to depend on surgery type.

CONCLUSIONS

With regard to the existing literature, the use of closed-suction drainage in elective thoracolumbar spinal surgery is not associated with any proven benefit for patients and cannot decrease postoperative complications.

Interspecies variation in liver weight, hepatic blood flow, and antipyrine intrinsic clearance: extrapolation of data to benzodiazepines and phenytoin

The literature was reviewed to obtain data from 11 mammalian species on liver weight, hepatic blood flow, and antipyrine intrinsic clearance. It was demonstrated that liver weight and hepatic blood flow in all species could be readily related to body weight by a simple equation. Additionally, hepatic blood flow in all species was directly proportional to liver weight. With the exception of man, antipyrine intrinsic clearance was also directly proportional to liver weight. Man's intrinsic clearance was approximately one-seventh of that which would be predicted from other species. Data on benzodiazepines and phenytoin showed a similar pattern.

Estimation of plasma unbound phenobarbital concentration by using mixed saliva

Relationships among plasma total (Ct), plasma protein unbound (Cf) and mixed salivary (Cs) concentrations of phenobarbital (PB) were studied in 29 epileptic patients. A highly significant correlation was observed between Ct and Cf. Although a significant correlation was observed between Cf and Cs, Cs/Cf ratio was only 0.63. When Cs was corrected by using pKa (7.41) and pH of saliva to estimate free PB concentration (Cest f), a highly significant correlation was obtained between Cf and Cest f, and Cest f/Cr ratio was 0.96. The temporal course of Cest f obtained from Cs after an oral single dose of 50 mg PB in a healthy adult male volunteer was approximated as a triexponential equation. The peak time was 2 hr after ingestion and apparent half life was 66 hr. The prediction of minimum concentrations at steady state on the basis of these parameters corresponded well with actually obtained Cest f following repetitive administration of PB.

Application of amberlite XAD-2 resin for general toxicological analysis

The use of Amberlite XAD-2 resin for the extraction of drugs has been extended to the processing of either direct aliquots of blood and stomach contents or aqueous dialysates of the latter, as well as to that of aqueous Stas-Otto deproteinated extracts of tissue. A two-step elution provides the subsequent recovery of standard acid, neutral, basic compounds, and the more polar, water-soluble drugs and drug metabolites. Inorganics may be recovered from the eluate resulting from passage of the original solution through the resin. Extraction with columns of 1-2 g of Amberlite XAD-2 resin is shown to provide the best general approach for separations in pure form of nearly all toxic compounds from up to 500 g of tissue as well as from biological fluids and stomach contents.

An improved benzophenone procedure for the micro-determination of 5,5-diphenylhydantoin in blood

A micro-modification of the benzophenone procedure proposed by Wallace for the determination of 5,5-diphenylhydantoin in blood is described which does not require specialised glassware and avoids the interferance caused by chloroform. In the new procedure 5,5-diphenylhydantoin is extracted from blood with 1,2-dichloroethane, returned to alkali, washed with n-heptane, and oxidised with permanganate in small teflon lined screw capped test tubes containing a layer of n-heptane. The absorbance of the oxidation product (benzophenone) is measured spectrophotometrically on an expanded scale using semi micro cuvettes. The method requires 100-200 mul sample and has a detection threshold of less than 0.1 mg/100 ml.