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 Ultrasound is used in medicine for imaging, therapy and for measurement of blood velocity. The use of this low energy, non-ionising waveform means that ultrasound exposures are thought to be less hazardous than other imaging modalities, though mild local tissue heating occurs with absorption of ultrasound energy. Ultrasonic vibration is defined as being in the bandwidth of 20 kHz to the MHz range, above human hearing ability. An ultrasound probe or transducer consists of a piezoelectric crystal, which me­chanically generates and transmits a vibrating pressure wave in a tissue in response to an alternating electrical input (Fig 1A). Conversely, it also transduces an alternating electrical output in response to a vibrating pressure wave input from the tissue. Hence, the piezoelectric crystal can be used both to transmit a pressure wave and to detect a reflected wave (Fig 1B). The reflection of the ultrasound wave at the interface between two tissues of different densities, or at tissue...

 Pre-operative Management Pre-operative Assessment "People don't die of their diseases: they die of the pathophysiological effects of disease." Sir William Osler 1897. Pre-operative assessment should aim to identify risk factors which could be optimised to minimize complications, improve outcome and ensure patient safety and comfort. AIMS . Establish rapport the patient and family, and allay anxiety. Assess functional status, optimise and balance risk and benefit. Plan peri-operative management according to the risk factors. Explain all procedures, establish communication and obtain informed consent. HISTORY Vital and most informative and cannot be substituted for by investigations Age : biological age is more important than chronological age Profession, lifestyle, effort tolerance and metabolic equivalents (see page 10.1) Presenting complaint, its complications and surgery planned Current and past medical diseases, drug therapy, sepsis, allergies Coagulopathy: gum bleedi...

 LOCAL ANAESTHETIC AGENTS (see page 19.23 for toxicity) Lignocaine : Low lipid solubility and potency (use 0.5-2%); low pKa 7.9 onset 5-10 min.); low protein binding 70% (duration short 30-60 min); maximum safe dose (MSD) 3 mg/kg. Vasodilates, so use with adrenaline to increase duration to 2-3h, and MSD to 7 mg/kg. Bupivacaine : High lipid solubility (use 0.1-0.5%); high pKa 8.1 (onset 10-15min): high protein binding 95% (duration 2-4h). No vasodilatation. MSD 2mg/kg. Ropivacaine : Pure 'S' enantiomer of bupivacaine, with less lipophylicity, toxicity, and motor block, and therefore most useful for nerve blocks, labour and post operative pain relief. Use 0.2%. Onset 10 min. Duration 2-6h. MSD 3-4mg/kg. PRE-OPERATIVE ASSESSMENT Similar to that of general anaesthesia but should specifically include: 1. An examination of the spine (kyphoscoliosis, skin lesions, local sepsis and fat deposition which renders landmark identification difficult) 2. Evaluation of coagulopathy and anticoa...

 Abstract Background: Estimating intraoperative blood loss can be a difficult task, especially when blood is mostly absorbed by gauze. In this study, we haveprovidedanimprovedmethodforestimatingbloodthatwasabsorbedbygauze. Objectives: To developaguidethatmedicalstaffcanusetoestimatebloodlossthatwasabsorbedbysurgicalgauze. Materials and Methods: Aclinical experiment was conducted using expired blood and commonsizes of surgical gauze to create a realistic stain of absorbed blood inthegauze. Differentpercentagesof stainingwerephotographedtocreateananalogueforthe amountof bloodabsorbedbythegauze. Results: A visual analogue was created to aid the estimation of blood absorbed by the gauze. The absorptive capacity of different gauzesizeswasdeterminedwhenthegauzewasdrippingwithblood. Theamountof reductioninabsorptionwasalsodetermined whenthegauzewaswettedwithnormalsalinebeforeuse. Conclusions: Theuseofavisualanaloguewillincreasetheaccuracyofbloodlossestimationanddecreasetheconsequencesrela...

 The Airway "An opening must be attempted in the trunk of the trachea, into which a tube of reed or cane should be put; you will then blow into this, so that the lung may rise again and the heart becomes strong." Vesalius 1555 The anaesthetist is responsible for maintenance of the airway and gas exchange. 28% of deaths due to anaesthesia are due to inability to intubate or ventilate (ASA). Normal airway patency is maintained by tension in the muscles connecting the larynx to the sternum, skull and mandible. Contraction of the pharyngeal dilator and tongue muscles opens the airway in a phasic manner during inspiration. Loss of muscle tension due to deep sleep, alcohol, sedation or disease may lead to pharyngeal obstruction, specially in the presence of anatomical abnormalities. The oropharynx is most prone to obstruction (posterior border of the tongue). As it is also part of the gastro-intestinal tract the protective airway reflexes are essential to prevent aspiration. Manage...

 Regional Anaesthesia Neuraxial Blockade Neuraxial (central) block with subarachnoid (SAB) or epidural (EDB) injection of local anaesthetic (LA) can provide excellent peri-operative anaesthesia and analgesia with many advantages over general anaesthesia. ADVANTAGES Comparative advantages over general anaesthesia • Stress response and the hypercoagulable state due to surgery are minimized. • Pre-emptive, intra, and post operative analgesia • Reduced bleeding • Muscle relaxation with spontaneous respiration • Thrombo embolism is reduced in the high risk patient. • Safer recovery, early mobilization and feeding, and better respiratory outcome • Minimal equipment and drugs which reduces cost A voids disadvantages of general anaesthesia • Unconsciousness, loss of protective reflexes, difficult airway • Awareness, PONY, sore throat, hangover • Gaseous pollution • Equipment hazards • High cost CONTRAINDICATIONS TO CENTRAL BLOCKADE Absolute • Patient refusal of technique • Sepsis at the si...

 Type 2 Diabetes Mellitus Medication: Antidiabetics, Biguanides, Antidiabetics, Sulfonylureas, Antidiabetics, Meglitinide Derivatives, Antidiabetics, Alpha-Glucosidase Inhibitors, Antidiabetics, Thiazolidinediones, Antidiabetics, Glucagonlike Peptide-1 Agonists, Antidiabetics, Dipeptidyl Peptidase IV Inhibitors, Antidiabetics, Amylinomimetics, Selective Sodium-Glucose Transporter-2 Inhibitors, Bile Acid Sequestrants, Antidiabetics, Rapid-Acting Insulins, Antidiabetics, Short-Acting Insulins, Antidiabetics, Intermediate-Acting Insulins, Antidiabetics, Long-Acting Insulins, Dopamine Agonists Updated: Dec 24, 2020 Share Feedback Medication Summary Pharmacologic therapy of type 2 diabetes has changed dramatically in the last 10 years, with new drugs and drug classes becoming available. These drugs allow for the use of combination oral therapy, often with improvement in glycemic control that was previously beyond the reach of medical therapy. Agents used in diabetic therapy include the ...