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The pentose cycle or direct oxidative pathway (DOP) may be defined as the sleep and synthesis pathway. It produces NADPH2, fatty acids, amino acids, nucleotides, hormones, nucleic acids, CoA, FAD and so on; the synthesis of glucuronic acid and hyaluronic acid is considered..

Transformation of glutamate, one of the most potent exciter neurotransmitters, into Gamma-aminobutyric acid (GABA), one of the most potent inhibitors; the action of vitamin B6 as a coenzyme, as well as antiemetic; the functions of magnesium; and sodium gamma-hydroxybutyric acid (GHB) are described.

Thiamine is considered not just as a vitamin, but also as a drug: for anaesthesia, analgesia and intensive care.

Blood–brain barrier characteristics are analyzed, which must be considered to be much more than a connective supporting tissue between the neurons and the capillary endothelium.

The various historic hypotheses regarding narcosis are reviewed. The chapter closes with the action on the multimodal receptors of inhalatory anaesthetics.

The authors consider the possible correlations between certain alterations of the neurotransmitters of the central nervous system and two common clinical syndromes: schizophrenia and depression.

Normobaric oxygen therapy is easy to administer in stay wards with a face mask. It has many effects: antibacterial action; anti-oedema effect; repairs soft tissues; stimulates the activity of the osteoblasts.

Krebs cycle, present in cells containing mitochondria, is described in an easily memorisable logical sequence. It is also explained why, when a patient is mechanically ventilated, care must be taken not to fall below 25 mmHg of PaCO2.

It is explained how enzymes and coenzymes work: molecules which facilitate biochemical reactions in living organisms.

The author explains how biochemistry can be useful to an anaesthesiologist or an intensivist. Some random examples are given.

The acid–base equilibrium is explained in a simple, linear manner. Pathogenesis and therapy of its basic modifications, acidosis and alkalosis, respiratory and metabolic, are described.

Perineural administration of thiamine, via axonal flow, could strenghthen synthesis of ACh in the dorsal horn inhibitory interneurons, thus potentiating analgesia. The purpose of the present retrospective analysis is therefore to investigate whether adding perineurally 2 mg/Kg of thiamine to 0.75% levobupivacaine in patients undergoing middle interscalene block may prolong the duration of analgesia.The hospital records of all ASA status 1-2 patients, undergoing a single-shot interscalene block for arthroscopic rotator cuff repair from January 2011 to May 2012 were retrospectively reviewed. All blocks were performed with 0.75% levobupivacaine or a solution of thiamine hydrochloride and 0.75% levobupivacaine. The local anesthetic solution, postoperative visual analogue score for pain at rest and rescue medication were registered. We calculated the time interval elapsing between block anesthetic mixture injection and the patient's first analgesic requirement, ie time to end of analgesia. Eventual postoperative side effects were also reported.59 patients received 0.4 ml/Kg of 0.75% levobupivacaine (Group L) and 51 patients received a mixture of 2 mg/Kg of thiamine hydrocloride (maximum dose 200 mg) with 0.4 ml/Kg of 0.75% levobupivacaine (Group B1). Tea was 11.4 ± 3.0 hours in Group L versus 17.6 ± 3.0 hours in Group B1 (p0.001). The scores for pain in the two Groups at the time of the first analgesic rescue were comparable.The present retrospective analysis suggests that thiamine helps to prolong postoperative analgesia when added to the local anesthetic solution. Further prospective studies are necessary to confirm these preliminary results.Word count: 250.

A variety of brachial plexus block techniques via the interscalene approach have been proposed. We describe here a new middle interscalene perivascular approach to the brachial plexus. To verify its effectiveness, we studied 719 patients scheduled for shoulder arthroscopy. Furthermore, to verify the accuracy of the proposed bony landmarks to use in the case of inability to palpate the subclavian artery pulse, we simulated the block on 10 cadavers.The aim of our technique is to cannulate the neurovascular bundle by inserting a 35-mm needle lateral to the subclavian arterial pulse near the midpoint of the upper edge of the clavicle in a horizontal or slightly cephalad direction while pointing toward the seventh cervical vertebra. If the pulse of the subclavian artery is not palpable, we localize the direction of the needle with reference to 3 bony landmarks (the middle point of the clavicle, the spinous process of C7, and the sternoclavicular joint). By connecting these 3 landmarks, we obtain an angle whose apex lies at the midpoint of the clavicle and its bisecting line points to the plexus. The needle is introduced in the transverse plane of C7.The block was performed successfully in 692 of 719 cases (96.2%). Horner's syndrome occurred in 93.5% of the cases, arterial puncture with hematoma occurred in1%, phrenic nerve block without respiratory impairment in 60%, with transient respiratory failure in1%, and laryngeal nerve block in1%. The incidence of severe complications or permanent injuries was zero (upper limit 95% confidence interval = 0.4% or 1:250 patients). The technique performed on cadavers showed that the previously mentioned bony landmarks were reliable reference points in reaching the brachial plexus.Our technique via a middle interscalene approach is easy to perform and provides a high success rate. Even in the absence of a subclavian artery pulse, the easily recognizable bony landmarks reliably guide us in the insertion of the needle. Furthermore, this technique appears to avoid complications that are theoretically possible in other supraclavicular perivascular approaches (pneumothorax) and paravertebral approaches (injection into the vertebral artery and subarachnoidal injection). However, further comparative studies will be required to assess the clinical relevance of the block.