Postdural puncture headache PDPH

The incidence of PDPH is 0.5-1 and is often higher in teaching hospitals. It may occur at the time of epidural insertion or be caused later by catheter migration into the intrathecal space. The clinical presentation is of an occipital headache which may radiate anteriorly, aggravated by sitting and possibly associated with nausea, photophobia and, rarely, diplopia resulting from stretching of the Vlth cranial nerve as it passes through the dura. The differential diagnosis of meningitis,...

Reduction in secretions

Ether stimulated the production of secretions from pharyngeal and bronchial glands and premedication with an anticholinergic agent was common. This problem occurs rarely with modern anaesthetic agents, and anticholinergic premedication is no longer used as a routine. However, premedication with an anticholinergic drug is advisable for patients in whom an awake fibreoptic intubation is planned (when excessive salivation can create extra difficulty), or before using ketamine. Sedation is not...

ATI receptor antagonists

Angiotensin II receptor antagonists selectively block the type 1 A-II receptor (ATj receptor). They inhibit the RAS independently from the source of A-II and block any effects of ATI resulting from com pensatory stimulation of renin, such as reflex activation of the sympathetic nervous system. Hence, they do not cause tachycardia or an increase in cardiac contractility and are used in the treatment of hypertension. However, they are ineffective in primary hyperaldos-teronism. Their...

Extracorporeal gas exchange ECGE

This technique, also termed extracorporeal membrane oxygenation (ECMO), represents the final option if all other avenues of providing ventilatory support have failed. Partial cardiopulmonary venovenous bypass is initiated using heparin-bonded vascular catheters, and extracorporeal oxygenation and carbon dioxide removal are achieved using a membrane oxygenator. A low-volume, low-pressure, low-frequency regimen of ventilation is con- Inadequate An ious and agitated or restless, or both Desired...

Rheumatoid Arthritis

Patients with rheumatoid arthritis may present for synovectomy, arthrodesis, major joint replacement or soft tissue procedures such as nerve decompression or tendon surgery. Any affected joint may be painful and special care is needed during i.v. cannulation when the disease involves joints in the hand. It may be an ordeal for the patient to lie still under prolonged regional anaesthesia for surgery on one joint because of pain in other joints. The disease affects the cervical spine in up to 80...

Anaesthesia And Electroconvulsive Therapy

Electroconvulsive therapy is used widely in psychiatric practice, with over 100 000 treatments being administered to patients in England each year under general anaesthesia ECT is therefore an important topic for anaesthetists. ECT is a highly successful treatment for severe depression and some other psychiatric disorders. It is often quicker, safer and more effective and has fewer side-effects than drug therapy. Originally, seizures were induced chemically and electrical stimulation was not...

Insulin

Some of the insulin preparations in common use are listed in Table 35.7. The best control is achieved by twice-daily injections of short- and intermediate-acting insulin. Increasingly, younger diabetics are managed with a background once-daily ultra-long-acting preparation coupled with a pen injector delivering small doses of short-acting insulin. The type of preparation must be noted, and if a change is made in the type of insulin (bovine, porcine, human) the dose must be adjusted, because...

Contraindications To Induced Ettpotension Table 562

The development of arterial plaques and thickening of vessel walls which occur in patients with peripheral vascular disease limit the ability of arteries to either constrict or dilate. Blood flow through these vessels becomes dependent on the diameter of the lumen and the pressure gradient across the vessel. If the diameter of the lumen cannot be altered, then flow is related directly to arterial pressure. During controlled hypotension, the ability to autoregu-late is lost, and perfusion of the...

Temperature Regulation And Maintenance

Homeothermic animals possess the ability to produce and dissipate heat. Heat loss occurs by one of four processes radiation, convection, evaporation and conduction. The environment in which the patient is situated governs the relative contribution of each. The neutral thermal environment is defined as the range of ambient temperatures at which temperature regulation is achieved by non-evaporative physical processes alone. The metabolic rate at this temperature is minimal. The temperature of...

Tricyclic Antidepressants

Tricyclic antidepressants inhibit the reuptake of norepinephrine into the presynaptic nerve terminals. Most of these drugs also have anticholinergic effects. Tricyclic antidepressants may produce tachycardia and arrhythmias even in therapeutic doses and the hypertensive response to directly acting sympathomimetic amines is increased dramatically. Although it has been recommended that tricyclic antidepressants are discontinued 2 weeks before anaesthesia, this may not be possible in many...

Electrolyte disturbances

Sodium retention occurs in renal failure, and through increased secretion of ADH is associated with water retention, oedema and hypertension. Hyponatraemia is also common in renal disease. It is the result either of sodium losses through the kidney or gastrointestinal tract, or of water overload causing dilutional hyponatraemia. The renal tubules may have a reduced ability to conserve sodium (e.g. in pyelonephritis, analgesic nephropathy or recovering acute renal failure), or sodium may be lost...

Management of chronic pain

Recent advances in the understanding of the fundamental mechanisms involved in the transmission and modulation of noxious impulses have significantly extended the range of assessment tools and treatments clinicians offer to patients with pain. The majority of medical pain specialists in the UK are anaesthetists. Historically, anaesthetists have been responsible for the relief of pain in the perioperative period and have developed skills in percutaneous neural blockade. This expertise, developed...

Drugs Used For The Treatment Of Hypertension

A wide variety of drugs are used to treat hypertension, including a- and p blockers, diuretics, calcium channel blockers, ACE inhibitors, AT -receptor antagonists, and vasodilators (Table 7.16). Non-pharmacological strategies include weight reduction, a decrease in alcohol intake and the institution of a low-sodium (with or without high potassium) diet with regular exercise. If these measures fail, drug therapy is indicated. Recent guidelines from the UK and the USA have emphasized the need for...

Emergency surgery and diabetic ketoacidosis

Diabetic ketoacidosis results from inadequate insulin dosage or increased insulin requirements, often precipitated by infection, trauma or surgical stress. Diabetics who require emergency surgery often have a grossly elevated blood glucose concentration and occasionally overt ketoacidosis. Such patients require rehydration, correction of sodium depletion, correction of subsequent potassium depletion and i.v. soluble (Humulin S) insulin by infusion at an initial rate of 4-8 unit h l. Initial...

Consequences of hyponatraemia

Symptoms vary with the underlying aetiology, the magnitude of the reduction of plasma sodium and the rapidity with which the EVALUATION OF EXTRACELLULAR FLUID VOLUME Diarrhoea Vomiting Third space losses Diuretic abuse Hypoadrenalism Salt losing nephropathy Renal tubular acidoses Diarrhoea Vomiting Third space losses Low SIADH SIIVT Drugs Hypothyroid Stress (post-op) Renal failure Depletional syndromes Saline required Dilutional syndromes Fluid restriction required

Thiazide Diuretics

Although thiazide diuretics are seldom used by anaesthetists, many patients scheduled for surgery are receiving these drugs for chronic hypertension or cardiac failure. There are a large number of thiazides available, all with a similar dose-response curve and diuretic effect. Bendroflumethiazide, chlorothiazide, hydrochlorothiazide and chlorthalidone are a few examples of the better known thiazide diuretics. The majority have a duration of action of 6-12 h. In comparison with loop diuretics,...

Disorders Of Sodiumwater Balance Hypernatraemia

Hypernatraemia is defined as a plasma sodium concentration of more than 150 mmol L-1 and may result from pure water loss, hypotonic fluid loss or salt gain. In the first two conditions, ECFV is reduced, whereas salt gain is associated with an expanded ECFV. For this reason, the clinical assessment of volaemic status is important in the diagnosis and management of hypernatraemic states. The common causes of hypernatraemia are summarized in Table 39.3. The abnormality common to all hypernatraemic...

Cancer Immunotherapy

Several experimental immunotherapy regimens have been used in the treatment of cancer. Injections of cytokines, including IFN and TNF-a, have been shown to be beneficial in some cancers. However, cytokine therapy may also result in unwanted side-effects, including fever, hypotension and decreased leucocyte counts. In vitro activation of lymphocytes with irradiated tumour cells in the presence of IL-2 has also been used. This approach results in induction of lymphokine-activated cells (LAK...

Disseminated Intravascular Coagulation

This is also referred to as consumption coagulopathy, which reflects the pathogenesis. Essentially, the process represents the inappropriate triggering of the coagulation cascade in flowing blood by specific disease processes. There is considerable variation in severity, ranging from the coagulopathy as the predominant clinical manifestation (with haemostatic failure) to merely a laboratory sign of the underlying disease with no clinical haemostatic lesion. Some possible causes are listed in...

Mapleson E and F systems

The Mapleson E system, or Ayre's T-piece, has virtually no resistance to expiration and was used extensively in paediatric anaesthesia before the advantages of continuous positive airways pressure (CPAP) were recognized. It functions in a manner similar to the Mapleson D system in that the corrugated tube fills with a mixture of exhaled and fresh gas during expiration and with fresh gas during the expiratory pause. Rebreathing is prevented if the FGF rate is 2.5-3 times the patient's minute...