589 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from

POST-OPERATIVE FLUID COMPLICATIONS By B. J. HOUGHTON, M.B., B.S. Lately Clinical Research Fellow, Surgical Unit, St. Mary's Hospital

Changes in the and content of some familiarity with the factors involved in order the body tissues after surgical operations occur as to understand the nature of the disorders seen the result of two factors. On the one hand, after he has been submitted to a major surgical there are the various changes consequent upon operation. Although the existence of ' osmo- altered intake and excessive loss of these materials, receptors ' has been clearly indicated following as, for example, in disorders affecting the gastro- the pioneer work of Verney (I947), there is, as intestinal tract and with haemorrhage, and on the yet, little known about the mechanism of control other hand, there are several less specific but of the overall fluid volume, although a ' volume equally important changes which occur as the receptor ' was postulated in I948 by Peters and physiological response to trauma. The latter, Borst. In the normal course of events it appears which were first observed in detail by Cuth- that the body maintains the pH and osmolarity bertson (1930) and have been studied minutely in (osmotic solute content) of the fluids bathing the recent years (Moore and Ball, 1952; Wilkinson cells with more vigour than the total and volume, Protected by copyright. et al., I950, and others), are reviewed elsewhere in this is, perhaps, not surprising in view of the this issue and will only be mentioned here in changes in the latter that occur with intestinal relation to the genesis and treatment of individual absorption after feeding. However, there are fluid and electrolyte disturbances. It is often clinical situations, for example, severe sodium argued that patients survived major surgical opera- depletion and haemorrhage, in which maintenance tions and illnesses long before these newer ideas of constancy of volume eventually takes prece- were conceived, but, of course, the same is true dence over osmolarity and acid-base balance con- for antibiotics and modern anaesthesia, the value trol, and similar observations have been made of which no one would deny, and prevention of a under experimental conditions (McCance, I936). complication still remai'ns better than its cure. The disturbances of that occur in Mortality figures can be improved by such means, surgical conditions can be grouped in several as they were amongst cases of infantile diarrhoea ways, their essential nature having been elucidated when potassium supplements were first tried and described by a large number of workers (Darrow, I946). It is probably no exaggeration (Gamble, Hartmann, Darrow, Coller and Mad- to say that many patients who in the past suc- dock, Cuthbertson, Marriott, McCance, Elkinton http://pmj.bmj.com/ cumbed to the after-effects of an operation did so and many others). In the first place we must not from ' toxaemia ' or' shock' but from a then consider the disorders leading to alteration of unrecognized biochemical complication. This, total fluid and electrolyte content, and, therefore, then, is the justification for yet another review of changes of osmolarity. Later it will be necessary our present knowledge in this field, which is the to review the changes in acid-base balance and the concern of clinician, pathologist and physiologist special role of potassium, and to consider the

alike. complications due to disorders of cardio-respira- on September 29, 2021 by guest. tory, renal and suprarenal function in altering the General Considerations response of the organism. The final and major Claud Bernard emphasized the importance to object of this discussion must be to outline living organisms of maintenance of the constancy methods of avoiding these hazards in routine of the ' milieu interieur,' and during the course surgical practice. of evolution an elaborate system of homeostatic mechanisms has developed by which this is Disturbances of the Total Body Fluid and achieved. Consequently, we find in man a Electrolyte Content remarkable constancy in the water and electro- These may consist of a deficiency or excess of lyte content, acid-base balance and volume of the water or , or both, and a mixture of body fluids, and it is clearly necessary to have these conditions is commonly encountered. 590 POSTGRADUATE MEDICAL JOURNAL December 1957Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from The Depletion Syndromes sonality change, impaired mental function leading The clinical state generally described as ' de- to stupor, and a marked rise in the plasma sodium hydration' may consist either of loss of water by concentration (and other evidence of haemo- itself (the true meaning of the term) or loss of concentration) may occur. If treatment is not water and variable amounts of sodium salts. In commenced immediately, hyperpyrexia and death view of the marked clinical differences between ensue. these states it is probably best to avoid the term Administration of water in adequate quantities altogether and to use Marriott's produces a complete regression of symptoms and classification, as follows here. signs, and the restoration of a normal urine output. (i) Water Depletion. Loss of water occurs in two ways: namely, by extrarenal routes as vapour (ii) Sodium Depletion (Salt Depletion). The in the expired air, insensible skin loss, sweat, and average normal diet for man contains 8o to 150 water in the faeces, and by renal excretion as mEq. of sodium per 24 hours. Apart from a urine. The insensible skin loss and respiratory small amount (3 to 5 mEq.) which is lost in the water loss was estimated by Dubois in 1927, who skin secretions and also in the faeces (3 to 5 mEq.), found it to be an average of 0.5 g. of water per an equivalent amount is lost in the urine. In kg. body weight per hour in adults, and this has health the body can maintain homeostasis on a been confirmed by others. Thus for a 70-kg. man fraction of this intake, and that this is possible is the total loss is approximately 840 ml. per 24 due to an efficient sodium conservation mechanism hours, and this is increased in febrile conditions in the kidney, which is apparently mainly under and elevation of the metabolic rate. Faecal loss the control of the hormones of the adrenal cortex. of water clearly varies considerably, depending on In renal disease such as chronic pyelonephritis many factors, but allowing an average of I50 ml. and chronic glomerulonephritis, and in adrenal per 24 hours, and not less than 5oo ml. of urine cortical insufficiency (Addison's disease) excessive over the same period, the minimum obligatory and uncontrolled sodium losses in the urine mayProtected by copyright. loss of water in health is generally accepted as occur, and therefore it is important to remember approximately I,500 ml. per 24 hours. Hence if this effect when such a patient has to have an the available water is less than this volume, or operation, for in contrast to the normal person there is excessive loss from one or more of these who excretes very little sodium in the urine in the routes, water depletion is bound to occur. first four or five days, as part of the physiological Intake of water may be deficient due to coma response to trauma, these patients may continue or inadequate parenteral administration where the to lose large amounts. oral route is contraindicated, or it may be rela- As apart from these special conditions a deficient tively insufficient compared with the intake of sodium intake is compensated by a greatly reduced excretable solutes such as electrolytes and, in the output of sodium in the urine, it follows that the case of the diabetic patient, glucose. majority of cases of clinical sodium depletion Excessive loss may be from the skin in fever or occur as the result of excessive extrarenal losses a raised atmospheric temperature, hyperventila- and mainly, therefore, by vomiting, diarrhoea, or pooling of fluid in the gastro-intestinal tract or tion, and polyuria as seen, for example, in renal http://pmj.bmj.com/ insufficiency, glycosuria and . serous cavities. If the patient's fluid losses are The latter, of course, has a particular surgical repaired by water alone, or, at most, by sodium- importance in relation to hypophysectomy, as containing solutions of low concentration, then a nowadays practised for some forms of advanced state of sodium depletion (salt depletion) may malignant disease. occur whilst the total water content of the body is The cardinal feature of water depletion is normal. As might be expected, the plasma thirst, and it is this symptom which generally sodium, chloride and bicarbonate concentrations guides the clinician in assessing his patient's water are found to be low (the sodium may be as low on September 29, 2021 by guest. requirements. Clinical signs are relatively slight as izo mEq. per litre) and, in fact, the volume of at first, but as the condition becomes more severe the extracellular compartment is also reduced. and the body is depleted of 2 litres or more of A relatively high haematocrit is found as evidence water, dryness of the tongue and mucous mem- of haemoconcentration. branes is apparent, together with the production Reduction in the extracellular fluid volume of only small volumes of urine with a high specific causes lassitude and weakness, signs of loss of gravity. A high potassium concentration may be skin elasticity and tissue turgor, reduced blood found in the urine, and this is a reflection of the pressure and tachycardia, with a tendency to transfer of water and potassium from the reservoir fainting when sitting up. Oliguria and a rise in of cell fluid, the ' toxic' potassium being hastily blood urea follow, and if the condition is not excreted. In severe cases restlessness, a per- treated immediately, death results from oligaemia December 1957 HOUGHTON: Post-operative Fluid Complications Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from and uraemia ('pre-renal' or 'extra-renal' Excess water is distributed throughout all the uraemia). body fluid compartments, diluting them to an (iii) Mixed Water and Sodium Depletion. In equivalent extent in terms of osmotic strength fact these pure depletion syndromes described are (Wynn, I955). In the normal way, therefore, relatively uncommon, and the great majority of approximately two-thirds of the added water cases which are clinically ' dehydrated' are in accumulates inside the cells. The extent of fact suffering from combined water and salt deple- dilution of the body fluids is reflected in a lowered tion in varying proportions. The clinical features plasma sodium, chloride and bicarbonate, and are mainly those of sodium depletion although the the symptoms generally appear when the sodium patient may complain of thirst, and the blood is below I2o mEq. per litre. Initial symptoms are analysis findings vary with the nature of the lassitude, mental depression and confusion, nausea predominant deficits. In all cases a raised and vomiting. Later, restlessness, rapid respira- haematocrit will be found, unless, of course, the tions, spontaneous muscular twitching and drowsi- patient was grossly anaemic before his illness or ness appear and, if untreated, the patient slips into lost excessive blood during his operation. coma and may have generalized convulsions. The treatment of sodium depletion is adequate The reflexes may be exaggerated. replacement with this ion in the form of sodium Treatment depends on whether the patient is chloride. In most cases this will be given in capable of having a spontaneous diuresis, but isotonic solution (normal saline) because of the assuming this is not possible, these being the accompanying deficiency of water, but in cases of circumstances in which it usually occurs, then it pure sodium depletion with a normal body water is necessary to infuse hypertonic sodium chloride content, administration of a hypertonic solution intravenously at a slow rate. will be desirable. The quantities and principles of calculation will be considered later. (ii) Clinical Effects of Excess of Water and Sodium. This is the commonest form of fluid The Syndromes of Water and Electrolyte overloading and results when isotonic saline andProtected by copyright. Overloading dextrose-saline solutions are given in excess of the Much has been said and written in the past by patient's maximum output. It is therefore likely clinicians about the dangers of excessive intra- to occur chiefly during the first five post-operative venous infusions, but all too commonly the result- days or in cases of cardiac or renal failure. The ing condition is described loosely as ' water- excess of sodium salts is almost entirely confined logging' or ' overhydration' without stating to the extracellular fluid compartment, which is which components are in excess. However, the thereby expanded, causing haemodilution and effects of excess water or sodium, or both, give oedema with the appropriate risk of pulmonary just as definite clinical disorders as do the corre- oedema. Unless there is a relative excess of sponding depletions, and should always be con- water compared with the extra sodium, the sidered from this standpoint. patient's plasma sodium concentration will be (i) Clinical Effects of Excess of Water. It is normal. Treatment is, of course, to stop further difficult to produce symptoms in a normal healthy sodium administration, restrict water intake to person by excessive administration of water, that necessary to cover the obligatory losses, and, http://pmj.bmj.com/ whether by oral or parenteral routes, unless the if necessary, to adopt the measures for the treat- normal response is artificially inhibited ment of congestive cardiac failure. by injection of posterior pituitary extract. How- (iii) Clinical Effects of Excess of Sodium Salts ever, in the early post-operative period it is all too Alone. This situation is relatively uncommon easy, owing to the operation of an antidiuretic except where an unconscious patient has had his mechanism which is thought to be mediated via entire daily fluid requirements supplied in the the supraoptico-hypophyseal mechanism. Apart form of isotonic saline and is unable to express on September 29, 2021 by guest. from the obvious risk of too large an intravenous his thirst. Insensible water vapour loss con- infusion of dextrose-in-water solutions, the danger tinues to deprive him of about 8oo to I,ooo ml. of of rectally administered water is insufficiently water each 24 hours, and although oliguria realized, and this is due to a widely-held but develops, with a high electrolyte output, the erroneous belief that the body only absorbs the inevitable result is that the body fluids become required amount of water from the bowel. hypertonic. The clinical condition is essentially Unfortunately, the behaviour of the bowel in this the same. as that of water depletion, except that respect is extremely variable in different subjects when the patient is given the extra water that he and completely unpredictable, and some of the needs, slight oedema may appear temporarily until most severe cases of water intoxication have been excretion of the excess sodium (and water) is seen in these circumstances (de Takats, 193 I). effected. 592 POSTGRADUATE MEDICAL JOURNAL December 1957 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from THE HYPERNATRAEMIC SYNDROMES (Oliguria, dry mucous membranes) w (High plasma sodium) r 0 o0z /ater deeletion t sdiulectrolyteexcess Z z > rMixed NORMAL SODIUM Saline ' O ddepletions s CONCENTRATION *overloadings O Sodium depletion ; Symptomless Water excess < uu ghyponatraemia-- - I I (Oliguria, uraemia,) (Water diuresis later) u i ( hypotension ) 4' (Normal blood urea) I (Low plasma sodium) THE HYPONATRAEMIC (HYPOTONICITY) SYNDROMES FIG. i.-The 'tetrad' of osmotic syndromes.

Chronic Adjustments fluid in low and carefully limited concentrations,

The various disorders of osmolarity which have where it appears to be functionally related to Protected by copyright. been described can be represented as a tetrad nerve and muscle excitability. The exact con- (Fig. i), showing the differential diagnosis and centration is only of limited significance in relation similarities of the low and high osmolarity states, to the total body content, for raised plasma depletions and overloading syndromes. There is potassium levels may be found in the presence of one other condition which should be mentioned marked potassium depletion, and low levels in in connection with the low osmolarity states, and normal persons, but it appears to be related to the that is one which was observed by Coller and general cell metabolism according to whether the Maddock in 1940. It is now variously described cells are retaining or shedding it. Generally, as asymptomatic hyponatraemia, symptomless however, in surgical patients constant low plasma hypotonicity or chronic low salt syndrome, and concentrations are a feature of overall potassium it is found in many chronic wasting illnesses, such deficiency, and elevated levels are found in states as tuberculosis, carcinomatosis, post-operative of renal failure. sepsis, and fistulas. It is characterized by a low plasma sodium, which cannot be raised by ad- Potassium Deficiency ministering additional sodium in the diet, and, As excretion of potassium continues in all cir- http://pmj.bmj.com/ surprisingly, the absence of the symptoms of acute cumstances except anuria, depletion of the body salt depletion. It is probably related to chronic content can occur just as a result of deficient potassium and protein depletion and disappears if intake, in contrast to sodium. Recent work, how- and when the patient recovers from his illness. ever, has demonstrated that in conditions of Recently, however, it has been suggested that it persistent low intake, the potassium excretion represents a chronic excess of water and that it may be reduced considerably below normal. can be improved by the administration of corti- Urinary loss of potassium is increased in water on September 29, 2021 by guest. sone, which facilitates a spontaneous diuresis. depletion, or following rapid intravenous Thus it might be related to chronic suprarenal infusions of isotonic saline or dextrose solutions, hypoactivity. and large quantities may be lost in gastro-intestinal secretions. (The accompanying table shows the Disturbances of Potassium Balance average composition of various gastro-intestinal The clinical importance of potassium has fluids.) Evidence is accumulating (Darrow et al., mainly been recognized since Darrow (1946) 1948; Darrow and Pratt, I950; Cooke et al., described the beneficial effects of its administra- 1952; and others) that the lost intracellular po- tion in cases of infantile diarrhoea. It is, of tassium is replaced in part by sodium and hydrogen course, the predominant intracellular cation and ions, and that this results in an extracellular is only present in the blood and extracellular alkalosis. Another form of loss, in direct propor- December 1947 HOUGHTON: Post-operative Fuild Complications $93 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from tion to nitrogen loss, occurs as the result of extracellular fluid as a result of deranged carbor starvation and tissue catabolism following injury, hydrate metabolism. The hydrogen ions from and in these circumstances alkalosis is uncommon. these acids neutralize some of the plasma bicAr- The most useful evidence in diagnosing po- bonate producing a fall in its concentratiQn tassium depletion is a long history of loss of (reduced ' alkali reserve' or carbon dioxide com- secretions. The clinical features are variable but bining power) and a fall in the blood pH.; With essentially consist of weakness, lassitude, apathy, the low bicarbonate the plasma electrolyte patterm slurred slow speech, drowsiness and personality also reflects the in that the total of. changes. In addition, post-operative ileus may Cl+HCO3, which normally is about 8 to I1 mEql fail to recover, urinary incontinence may occur per litre less than the sodium level, is reduced; and the reflexes may be weak. The blood indicating the presence of the ketone anions, pressure is often low, and E.C.G. changes con- Renal failure gives a similar set of changes, the sisting of reduction in voltage, diminution or unusual anions in this case being excess of phos- inversion of the P waves, S-T depression and phate and sulphate, although there is, of courmo, inversion of T waves, prolongation of the Q-Tc an accompanying rise in the blood urea. Also, as intervals and the appearance of U waves are mentioned previously, sodium depletion can bc described, but are not necessarily present. the cause of this extrarenal uraemia and metabolic Treatment consists of replacement with po- acidosis. It is obviously of great importance to tassium salts, usually the chloride, which should watch for this state of affairs in surgical patients preferably be given by mouth, but may have to as a slight degree of is very be administered intravenously when oral feeding commonly found after any major operation, with is impracticable. the attendant low calorie intake and ketosis in th. immediately succeeding days. Potassium Excess A metabolic hyperchloraemic acidosis due to It is not possible to elevate the plasma potassium the accumulation of chloride ions may occur in Protected by copyright. in healthy persons to dangerous levels by excessive nephrotic patients, in cardiac cases after ammo- administration of potassium salts, and this is nium chloride administration and following trans- because of an efficient excretory mechanism in the plantation of the ureters into the lower bowel. kidneys. It follows that cases of potassium in- Clinical features are those of the causative con- toxication post-operatively occur as the result of dition, but when acidosis is advanced the patient renal failure or gross functional oliguria. There becomes disproportionately ill, has a low blood are few clinical signs except for a slow, irregular pressure and may have deep rapid respirations. heart beat, and this is commonly anticipated by The latter are due to the reduced plasma bicar-. E.C.G. changes consisting of peaked T waves, bonate (alkali reserve) which is unable to buffer prolonged PR interval and widened QRS com- the accumulating carbonic acid in the tissue fluids plexes, when the potassium concentration exceeds and blood, and as the result the respiratory centre 7 mEq. per litre. *is stimulated. Remembering that at the normal Acid-base Balance Disorders BHCO3==20 pH of blood, 7.4, the proportion H2C03 w ? http://pmj.bmj.com/ In the normal person regulation of acid-base equilibrium is maintained by the kidneys and, to it is apparent that when the BHCO3 is lowered, a lesser extent, by the respiratory system, and as in metabolic acidosis, a corresponding reduction disease of either may lead to profound biochemical of carbon dioxide tensi'on in the alveolar air by derangement. The acidosis consequent upon hyperventilation, and therefore the reduction of uncontrolled diabetes mellitus and upon renal blood carbon dioxide tension and H2CO3 concen- failure is well known, as is the alkalosis found in tration, is necessary to facilitate the correction of patients vomiting from pyloric stenosis, but the the pH towards normal. on September 29, 2021 by guest. acidosis and alkalosis found in respiratory dis- orders are less familiar to the general surgeon than to his physician colleagues. Essentially, the This may result from subtraction of acid, as in acid-base disturbances can be grouped into those the vomiting due to pyloric obstruction, and from of metabolic origin and. those due to respiratory excessive administration of alkali as, for examplr, disorders, and each will be mentioned separately. in ulcer patients treated continuously with alkaline preparations, and it is therefore important to tbhe Metabolic Acidosis surgeon chiefly as a pre-operative condition wliieh, The classical example of this condition is, of should be corrected before submitting the patient course, uncontrolled diabetes mellitus, in which to a surgical procedure. When due to alkali acid ketone bodies accumulate in the blood and ingestion the body attempts a4justment by S94 POSTGRADUATE MEDICAL JOURNAL December, 1957 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from secreting an alkaline urine containing sodium and tially a medical condition, and it would be inappro- bicarbonate ions, but when the alkalosis is due to priate to discuss it here except to say that such vomiting gastric juice the paradox of secretion of patients may be precipitated into the acute phase an acid urine is often found. This is due to very easily by infections, any post-operative chest actiVe sodium retention consequent upon loss of complication, or relaxant drugs. extracellular fluid, continued small losses of potassium in the gastric secretions and obligatory potassium loss in the urine, frequently resulting This is the opposite to and in an intracellular acidosis (Cooke et al., 1952). occurs in anaesthetized patients who are over- This biochemical complication is frequently found ventilated by the anaesthetist, and in conditions in patients vomiting post-operatively owing to a where the respiratory centre is stimulated directly. temporary pyloric or stomal block. The most familiar example of the latter seen by The alkalosis is characterized by irritability and the surgeon is in hepatic coma, where hyper- mental depression, cyclical periods of shallow ventilation is common and is due to primary respiration, almost amounting to apnoea, and stimulation ofthe respiratory centre by an unknown spontaneous tetany and myotatic irritability. The mechanism. In these circumstances excessive plasma bicarbonate is proportionately high (up to carbon dioxide is blown off with a resulting fall in 66 mEq. per litre), the chloride correspondingly the tension of the gas in the alveolar air and blood. low, and the plasma sodium may be elevated as A compensatory mechanism of metabolic acidosis the result of excessive sodium intake or excess and excretion of an alkaline urine subsequently water loss in vomiting. It is now thought that result in a return of the pH towards normal and potassium depletion plays a major part in the a fall in the plasma bicarbonate to levels below the causation of the alkalosis and that treatment normal range. should be, primarily, its correction with potassium The conditions described above had a fourfold chloride. relationship to one another, as have the syndromesProtected by copyright. of disorders of osmolarity, and may be portrayed Respiratory Acidosis in a similar manner (Fig. z). For the surgeon this is a relatively new hazard which has only come to the forefront since the Shock introduction of relaxant drugs in anaesthesia. The physiological and pathological responses These are particularly dangerous to patients with to acute haemorrhage and shock are well known, chronic respiratory insufficiency, e.g. chronic and so we can confine our attention here to the bronchitis and emphysema, and more than ever profound retention of sodium and water with before the patient is at the mercy of his attendants. resulting oliguria that occurs probably as the If he is returned to the ward before the effect of result of the operation of haemodynamic and the last injection of a relaxant agent has worn off, hormonal factors. or has been countered by prostigmine, he may' The prolonged hypotension which may follow have a sufficiently reduced respiratory excursion shock and oligaemia may, of course, lead to renal to,lead to a serious accumulation of carbon dioxide ischaemia and tubular necrosis, a serious corn- http://pmj.bmj.com/ and a consequent respiratory acidosis. The per- plication which in spite of careful conservative sistence of a pink colour, due to vaso-dilatation, management may be followed by a fatal issue. is a deceptive feature in a patient intoxicated with The principles of management in these circum- carbon dioxide and the diagnosis may be missed, stances are now firmly established along the lines for when the acidosis is severe the patient becomes suggested by Borst (1948), Bull, Joekes and Lowe deeply comatose, stops breathing and may develop (I949), and others, and essentially consist of signs suggestive of a cerebro-vascular accident, restriction of water intake to I,OOO ml. plus the including papilloedema and a raised C.S.F. urine volume, limitation of electrolyte intake to on September 29, 2021 by guest. pressure. that necessary to cover measured losses, and the Treatment consists of artificial ventilation with provision of a high glucose intake to supply a respirator until the excess of carbon dioxide has sufficient calories and reduce tissue catabolism. been blown off and the patient regains con- This regime can be given by intravenous or sciousness. intragastric routes. Chronic respiratory acidosis as in bronchitic subjects is characterized by an accumulation of The Influence of Co-existing Medical bicarbonate in the plasma to buffer the excess Conditions retained carbonic acid and, thus, restore the pro- Chronic Cardiac Disorders BHCO3 The effect of cardiac insufficiency on the post- pdrtion*H2C03H C and pH towards normal. It is essen- operative salt and water balance is important to December I957 HOUGHTON: Post-operative Fluid Complications 595 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from THE SYNDROMES OF ACIDOSIS Metabolic acidosis Respiratory acidosis ui j < tn Z °@tlooI d .05>>, L

has also been discussed earlier, but should be http://pmj.bmj.com/ Chronic Respiratory Disease emphasized again. Similar principles should This has already been discussed under acid- govern the management of patients subjected to base disorders. bilateral adrenalectomy, and in all these cases adequate substitution therapy with cortisone and Chronic Renal Disease desoxycorticosterone acetate is, of course, essential This, of course, may take many forms and is in if an Addisonian crisis is to be avoided. any case often a contraindication to any opera- tion other than an urgent lifesaving procedure. Diseases Requiring Cortisone Therapy on September 29, 2021 by guest. The importance of recognizing urinary sodium These are discussed elsewhere in this issue. loss in chronic renal disease has been mentioned, and the need to supply appropriately increased Liver Disease amounts of sodium salts in the post-operative Oliguria is a well-recognized feature in acute period should be assessed on the basis of the hepatic failure, but there are also important 24-hour urinary sodium output. changes in chronic cirrhotic disease. Although In the nephrotic syndrome and some cases of the mechanisms are far from clearly understood, chronic glomerular nephritis there is a marked the cardinal features are formation of ascites and sodium retention, and these cases must be oedema, consequent upon a raised portal venous managed with the same careful consideration as pressure and low plasma protein levels, and a in the cardiac cases. Again the 24-hour urinary tendency to retain sodium and water. The main- 596 POSTGRADUATE MEDICAL JOURNAL December 1957 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from tenance of a low urinary sodium output in spite malignant disease and it has been shown to lead of a normal intake may be due to increased pro- to an interesting biochemical complication, namely, duction or decreased inactivation of sodium- that of hyperchloraemic acidosis. Many theories retaining hormones (Bongiovanni and Eisen- have been advanced to explain this condition, but menger, 1951; Goldman and Bassett, 1952), and recent work by Parsons et al. (I952) has shown increased amounts of an anti-diuretic substance that chloride is reabsorbed from the urine accu- (Hall et al., 1949; Sims, I950) may account for mulating in the colon more quickly than is sodium. the persistence of an oliguria in spite of variations Patients affected by this condition may have in the intake. The low plasma protein levels nausea and vomiting, weakness and lassitude. undoubtedly assist the formation of peripheral Poor appetite leads to inadequate intake and oedema, but it may be that hormonal factors are significant potassium depletion may occur. Relief involved in the initial retention of salt and water. is usually affected easily by continuous drainage So far as the surgeon is concerned this means of the lower bowel with an indwelling tube, and that after operations on cirrhotic patients the the biochemical changes regress. However, occa- sodium and water intake must be very carefully sionally it may be necessary to administer potas- supervised, as one would in the case of cardiac sium, and this is best given as potassium citrate disease. mixture, 30 gr. three times a day (Wilkinson, 1954). Special Problems Associated with Surgery Principles of Post-operative Fluid Hypothermia Management Artificial cooling of patients being subjected to major cardiovascular surgery and certain other The first principle in preventing post-operative is a fluid complications is to have the patient in a operations relatively recent development and correctly balanced state when he goes to operation, has brought some special biochemical problems of and however urgent the surgical procedure its its own. Wynn (1954) has produced evidence that Protected by copyright. the metabolism of glucose is considerably reduced success can always be made the more certain by in hypothermia, and that the intravenous infusion spending a short while pre-operatively correcting of glucose or glucose-saline mixtures in these blood loss or gross fluid depletion. Post-opera- circumstances can lead to very high blood-sugar tively, the objectives are threefold: to correct loss levels, even in excess of i,ooo mg. per ioo ml. of circulating blood volume with blood, plasma, Because the glucose is not taken up by cells under dextran, etc., as the situation demands; to cover hypothermic conditions, the added glucose re- obligatory fluid and electrolyte losses; and to mains in the extracellular fluid and draws water replace losses incurred by vomiting and suchlike. out of the cells by osmotic forces, thereby render- It is with the latter two aspects that we are con- ing the cells relatively water-depleted. In order cerned here. to avoid this complication it has been recom- mended that 2.5 per cent. glucose solutions, to Fluid Requirements in Relation to the Stages of the halve the glucose load, or preferably plain saline Metabolic Response

solutiop3 should be used. (i) First 48 Hours. As mentioned earlier, in the http://pmj.bmj.com/ Another complication is that citrate ions, from first 24 to 48 hours after any major operation or the anticoagulant in donor blood bottles, are less general anaesthetic there is oliguria apparently easily metabolized and may accumulate in the due to primary water retention mediated by the patient's blood. They have recently been blamed pituitary antidiuretic mechanism. The small in cases of profound hypotension and cardiac volume of urine secreted is characterized by a arrest where decreased ionized calcium levels have high specific gravity and high electrolyte content, been demonstrated (Bunker et al., I955). Cal- but as the volume passed in the first 24 hours is cium salts have proved disappointing in the treat- seldom more than 6oo mL., it is uncommon for on September 29, 2021 by guest. ment and prevention of this condition. the total electrolyte loss to be more than about Free potassium ions may be present in stored 30 mEq. of sodium and 40 mEq. of potassium, donor blood in relatively high concentrations (up and it is usually less. The insensible fluid loss to io mEq. per litre) and thus rapid and large is often high in the first 24 hours, covering the bulk infusions in the hypothermic subject, whose period in the operating theatre, and may amount glucose metabolism is depressed, may be dan- to 900 to I,200 ml. The sodium loss from the gerous. Freshly-drawn blood is safer. skin is about 5 mEq. Hence the overall obliga- tory fluid loss in the first 24 hours is about I,500 Ureterocolostomy to I,8oo mi., and the electrolyte loss relatively This operation is now well established for cases small. Of course, vomiting,- diarrhoea, the drain- where total cystectomy has to be performed for age of fistulas, ascites and the like will add to the December 1957 HOUGHTON: Post-operative Fluid Complications 597 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from fluid and electrolyte loss, but this must be assessed and Houghton, in the press). As the total urinary and replaced appropriately to the individual case. (Na+K) losses usually amount to 6o to I00 mEq. The obligatory losses in each 24 hours can be per 24 hours, 750 ml. of normal saline per 24 hours covered by I,500 to i,8oo ml. of water and generally proves sufficient, with the additional approximately 70 mEq. of sodium, given as water supplied as dextrose solutions. Potassium sodium chloride, to replace sodium plus potassium. can be added to infusion solutions to the extent Thus, if the intravenous route is to be used, of 25 to 50 mEq. per 24 hours when large losses 500 ml. of normal saline may be given, and the are occurring, but this is safe only when the rest of the fluid as dextrose in water solutions. In patient is passing more than 8oo mL. of urine in situations where intravenous therapy is not neces- 24 hours. The accompanying table lists the sary, because the patient will be able to commence average composition of secretions from the gastro- oral fluid feeding within 48 hours or so and elec- intestinal tract and replacement of losses should trolyte losses are small, as, for example, after be arranged appropriately, using normal or half- uncomplicated partial gastrectomy, many surgeons normal sodium chloride solutions with potassium favour the rectal route and 3 pints (1,500 ml.) of chloride supplements. These figures are intended water per 24 hours is a common and satisfactory only as a guide, for the exact composition varies prescription. Whenever possible, the patient in individuals and direct analysis of these fluids should be allowed to take his fluids by mouth. should be performed whenever possible. Clearly during this phase of primary water retention the risk of excessive administration is Correction of Complications greatest, and water intoxication is a real danger The first essential is, of course, the establish- when fluid intake is not carefully supervised. ment ofa correct clinical and biochemical diagnosis, (ii) Third to Sixth Post-operative Days. After for the aim in treatment must be the correction the first 24 to 48 hours the oliguria passes off, but of the condition which has led to the clinical and the characteristic finding at this stage is that the biochemical state observed in the patient, and not Protected by copyright. sodium content of the urine is low (average just an attempt to ' put the figures right.' With Io mEq. per litre or less) and that the principal this in view it is clearly vital that accurate fluid cation excreted is potassium. The amount of the balance records should be kept for any patient latter which is lost seems to bear a rough direct subjected to a major surgical procedure, and also relationship to the severity of the operation and that whenever possible the patient should be metabolic response, and in some cases very large weighed before operation. A detailed clinical amounts (up to 150 mEq. per day) may be ex- examination and reference to the fluid balance creted in the urine. It is not surprising, therefore, charts will generally lead to the correct diagnosis, that many patients are quite markedly depleted of although in some cases this is not possible until potassium when they reach the sixth day of intra- the results of blood and urine analyses are avail- venous therapy unless some replacement of that able. In the absence of recent tissue wasting the ion has been prescribed, and it has been sug- presence in the adult of signs of loss of skin gested, for example, with some good evidence, elasticity represents the deficiency of not less that delay in recovery from post-operative ileus is than 2 litres of extracellular fluid. Estimations http://pmj.bmj.com/ often due to potassium deficiency (Streeten and of the plasma Na, K, Cl, HCO3 and urea should Ward-McQuaid, 1952; and others). Sodium be done whenever possible, and in the case of a should be adequately replaced if vomiting, diar- depleted patient will give information as to the rhoea and fistulas are producing sizeable losses, relative deficiency of water and sodium; e.g. if for otherwise there is a risk of salt depletion and, the plasma sodium is normal or low and the urea if a sudden increase in water intake occurs in raised, sodium depletion is present, and a falling these circumstances, superadded water intoxi- bicarbonate concentration represents a developing cation. metabolic acidosis. On the other hand, a high on September 29, 2021 by guest. Fluid prescriptions should aim to supply i,8oo bicarbonate and low chloride in this patient would ml. of water for obligatory losses (in addition suggest a metabolic alkalosis from loss of acid some I00 to 200 ml. of water is formed in 24 hours gastric secretions or from potassium depletion. from oxidation processes) and the appropriate Let us consider first a patient who has oli- sodium replacement for the urinary electrolyte guria, signs of loss of skin elasticity, dry mucous losses. The commonly described ' sodium para- membranes and hypotension, with a plasma dox' (Wilson et al.) of a falling plasma sodium sodium of I26 mEq. per litre, potassium 5.5 mEq. whilst the patient is kept in sodium and water per litre, chloride go mEq. per litre and bicar- balance may be observed if insufficient sodium is bonate 20 mEq. per litre. The clinical findings given to corer also the potassium losses, sodium indicate a loss of extracellular fluid, and the low and potassium being osmotically equivalent (Wynn plasma sodium shows that the electrolyte loss is 598 POSTGRADUATE MEDICAL JOURNAL December 1957 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from relatively greater than that of water. The lowered ments to fluid prescriptions can be made before bicarbonate and relatively greater reduction in the patient is filled with electrolytes which he will analysed anions compared with cations suggests be unable to excrete. Conservative treatment a metabolic acidosis. There are two aspects to can thus be commenced early. the fluid replacement in this case: first, the bulk Similar principles govern the calculations* for replacement of the missing extracellular fluid with the correction of all disorders, but one further an isotonic sodium solution; and secondly, the example, namely, acute water intoxication, may provision of additional sodium salts in appropriate be mentioned. Let us consider a female patient amounts to elevate the concentration in the existing who has had an elective partial gastrectomy and body fluids. However, as during the period of who, in the first 48 hours after operation, has intravenous correction therapy the patient will received a sufficiently large excess of water (by need water to cover the obligatory losses, this intravenous or rectal routes) to induce drowsiness additional sodium can usually be supplied in the and other signs of water intoxication. Let us, form of an isotonic solution if the infusion is furthermore, suppose that she is found to have a spread over more than 48 hours. In the normal plasma sodium of i i8 mEq. per litre and that her course of events 2 litres of normal saline may be pre-operative body weight was 6o kg. As the given fairly rapidly to restore extracellular fluid female generally has a slightly greater proportion volume, and the clinical signs of depletion should of body fat compared with a male of the same regress. A third, or even a fourth, litre may be weight we will assume that the initial total body given if clinically indicated whilst therapy is in water was approximately 50 per cent. of the body progress. In order to correct the existing low weight, i.e. in our patient the total body water sodium concentrations further calculations are was approximately 30 litres. If the patient's needed, as it is necessary to ascertain the amount plasma sodium was normally I40 mEq. per litre, of sodium that must be added to raise the concen- it follows that [(I40-I i8) x 30] mEq. or 66o mEq. trations in all the body fluid by the desired of sodium have been transferred into the addi-Protected by copyright. amount. If calculated on the basis of the extra- tional water, the volume of which was approxi- cellular fluid volume the infusion fails to produce mately (66o +-I8-5.6) litres. The amount of the expected rise in plasma sodium because in- sodium chloride necessary to restore the initial creased electrolyte concentrations in the extra- sodium concentration of I40 mEq. per litre to the cellular compartment result in the shift of water expanded total body water (35.6 litres) is thus from the cells and equilibration as if the sodium [(I40-1I8)X35.6]=783 mEq., and it must obvi- were distributed in the entire body water. Let ously be in hypertonic solution, say, approximately us suppose that our patient, a male, weighed 3 to 5 per cent. w/v. The infusion should be 70 kg. before operation and his total body fluid given into a large vein over a period of not less volume was therefore about 42 litres (6o per cent. than six hours, and the clinical improvement is of body weight), and that it is desired to raise his usually quite dramatic. As a general rule it is overall plasma sodium concentration to 140 mEq. wise to give only about two-thirds of the calcu- per litre. Sufficient sodium must be infused to lated amounts of sodium in the first 24 hours and raise the existing 40 litres of body fluid by to wait for a simultaneous diuresis. http://pmj.bmj.com/ (I4o-i26=4) mEq. per litre, and, therefore In situations where the plasma is hypertonic (40X14=56o) mEq. of sodium are necessary. with respect to sodium the simplest method is to This amount could be given as a hypertonic calculate the total excess of sodium salts present solution over a period of, say, 24 hours; or, better, and thus the volume of water necessary to dilute could be infused slowly as an isotonic solution them down to normal plasma concentrations. over a period of some 48 hours. It is advisable to repeat the blood analyses 24 hours after com- Summary and Conclusions mencement of intravenous therapy, for in this way on September 29, 2021 by guest. errors due to estimation of, say, the initial total The post-operative period carries certain special body water will not incur clinical risks. It is also hazards in relation to fluid and electrolyte balance, of vital importance to watch the state of the and disorders of body fluid volume, osmolarity circulation, especially in elderly patients in whom and acid-base balance may occur. the dangers of pulmonary oedema are great. It The fluid and electrolyte requirements of a is generally wise to lengthen the time period over patient post-operatively are dictated by the meta- which replacement is carried out in such patients. bolic response, and the general principles have A further advantage of a slower infusion is that it been considered. It is important, however, to allows an opportunity to observe the recovery of remember the influence of co-existing cardio- renal function and if a serious renal shutdown *The hasic formulae have been simplified in this such as in tubular necrosis has occurred adjust- account. 66o POSTGRADUATE MEDICAL JOURNAL December 1957 Postgrad Med J: first published as 10.1136/pgmj.33.386.589 on 1 December 1957. Downloaded from respiratory, renal and other diseases in modifying matical foundations can face the metabolic hazards the response of the patient, and newer surgical of surgery with confidence, anct avoid fluid com- techniques involving the use of relaxant drugs plications in his patients. and hypothermia bring their own peculiar problems. AVERAGE COMPOSITION OF SECRETIONS FROM Awareness of possible fluid complications is the THE GASTRO-INTESTINAL TRACT surest way of preventing them, and care taken in Composition pre-operative assessment and treatment is well (nimEq./litre) repaid in the smooth post-operative course. Nature When fluid and electrolyte losses have occurred, Na K Cl accurate quantitative assessment of the bio- Gastric 50 10 150 chemical derangement must be the prelude to Biliary I45 5 100 Pancreatic .. 'I45 5 75 plans for corrective therapy. Upper intestinal 1.40 10 100 In this way the surgeon building his prescrip- Ileostomy (established) . 50 5 25 tions on sound clinical, chemical and mathe- Diarrhoea fluid 1.45 15-20 75

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THYROID DISEASE (Postgraduate Medical Journal, July 1957) Price: 3s. 9d., post free http://pmj.bmj.com/ DIAGNOSTIC PROCEDURES IN THYROID RECENT WORK ON THYROID HORMONES DISEASE J. H. Wilkinson, B.Sc., Ph.D., F.R.I.C. Russell Fraser, M.D., F.R.C.P., D.P.M. SOME UNUSUAL MANIFESTATIONS OF THE PLACE OF RADIOACTIVE IODINE IN THYROID DISEASE THETHETREAITREATMNTHOFOTHYRIDSDISEASNTOFTHYROIDDISEASE W. R. Trotter, D.M., M.R.C.P. E. E. Pochin, M.D., F.R.C.P.

ANTITHYROID DRUGS CARCINOMA OF THE THYROID on September 29, 2021 by guest. James Crooks, M.B., M.R.C.P. (Lond. and John E. Piercy, F.R.C.S., F.R.C.S.E. Ed.), F.R.F.P.S.G. LYMPHOID GOITRES SUBACUTE THYROIDITIS T. Levitt, M.A., F.R.C.S.Eng., F.R.C.S.Ed., Selwyn Taylor, M.Ch., F.R.C.S. F.R.C.S.I. Published by THE FELLOWSHIP OF POSTGRADUATE MEDICINE 60, Portland Place, London, W.1