The effects of preanesthetic, anesthetic, and postoperative drugs on renal function

Fentanyl-associated syndrome of inappropriate antidiuretic hormone secretion

A 43-year-old woman with advanced pulmonary blastoma was admitted for worsening back pain. Her drug regimen included hydromorphone and benazepril. On admission, hydromorphone patient-controlled analgesia (PCA) was started for acute pain control and dexamethasone for possible cord compression. Baseline laboratory tests were unremarkable, but magnetic resonance imaging revealed T3 and L3 lesions. Irradiation was started with improvement in her pain. In anticipation of discharge, a fentanyl transdermal patch was given, and PCA was tapered. Two days later, the patient became progressively confused and fell. Neurologic examination and computed brain tomography were normal. Her serum sodium was 119 mEq/L (normal 136-144 mEq/L) and was confirmed on repeat testing, urine sodium was 194 mEq/L, and urine and serum osmolalities were 554 mOsm/kg (normal 300-900 mOsm/kg) and 245 mOsm/kg (normal 280-300 mOsm/kg), respectively, consistent with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Fluids were restricted, hydromorphone PCA was started again, and fentanyl was discontinued. After 36 hours, her serum sodium increased to 136 mEq/L. Because we were unsure whether the fentanyl or her cancer was causative and were unable to find any published reports of fentanyl-associated SIADH, we readministered the fentanyl patch 2 days later. Within 48 hours, serum sodium dropped to 123 mEq/L. Fentanyl was discontinued, fluids were restricted, and 3% saline was started. Her serum sodium increased to 132 mEq/L in 48 hours. The patient was prescribed oral hydromorphone and benazepril and was discharged. The repeated temporal relationship between the administration of fentanyl and the onset of SIADH strongly implicates fentanyl as the causative agent in this case. To our knowledge, this is the first report of fentanyl-associated SIADH.

Central alpha2-receptor mechanisms contribute to enhanced renal responses during ketamine-xylazine anesthesia

We have recently developed an experimental approach to study central opioid control of renal function in anesthetized rats. This model system uses the intravenous infusion of the alpha2-agonist xylazine to enhance basal levels of urine flow rate and urinary sodium excretion in ketamine-anesthetized rats. This study examined the contribution of central and peripheral alpha2-adrenergic receptor mechanisms in mediating the enhanced renal excretory responses produced by xylazine. In ketamine-anesthetized rats, the enhanced levels of urine flow rate and urinary sodium excretion produced by the intravenous infusion of xylazine were reversed by the intravenous bolus injection of the alpha2-adrenoceptor antagonist yohimbine but not by the alpha1-adrenoceptor antagonist terazosin. In separate animals the intracerebroventricular administration of yohimbine only reduced urine flow rate by approximately 50% but did not alter urinary sodium excretion. The decrease in urine flow rate produced by intracerebroventricular yohimbine was reversed by the intravenous injection of a selective V2-vasopressin receptor antagonist. In a separate group of ketamine- and xylazine-anesthetized rats, the bilateral microinjection of yohimbine into the hypothalamic paraventricular nucleus (PVN) also significantly decreased urine flow rate by 54% without altering urinary sodium excretion. The microinjection of the beta-adrenoceptor antagonist propranolol into the PVN did not alter either renal excretory parameter. These results suggest that during intravenous infusion, xylazine increases urine flow rate by activating alpha2-adrenergic receptors in the PVN, which in turn decrease vasopressin release. The ability of alpha-adrenergic mechanisms in the PVN to selectively influence the renal handling of water, but not sodium, may contribute to the reported dissociation of the natriuretic and diuretic responses of alpha2-adrenoceptor agonists.

Opioid mechanisms controlling renal function

1. Over the past 50 years considerable evidence has been reported suggesting that endogenous opioids participate in the control of renal function. 2. Exogenous administration of opioids produces profound changes in the renal excretion of water and sodium. 3. Opioids produce changes in urine output and urine sodium excretion by multiple integrated neural and hormonal mechanisms within the periphery, central nervous system and kidneys. 4. Although opioid antagonist administration does not consistently reveal an action of endogenous opioid systems on renal function, this may result from the quiescent nature of the endogenous opioid system under basal conditions. 5. Manipulations that activate endogenous opioid systems have begun to reveal important, previously unrecognized mechanisms that control kidney function and can enhance renal tubular sodium reabsorption in normal and potentially pathological states.

Anaesthesia for the patient with impaired renal function

Patients with renal disease are at risk of further deterioration of renal function and acute tubular necrosis when subjected to anaesthesia and surgery. Optimal fluid loading and careful selection of anaesthetic techniques and agents, appropriate monitoring and the use of mannitol and dopamine assist in the maintenance of renal blood flow and help preserve renal function in these patients. In association with renal failure, physiological changes in other systems result in reduced oxygen supply to the tissues, metabolic disturbances, impairment of the coagulation and immune defence mechanisms and an increased risk of cardiac and cerebrovascular catastrophe. Although many anaesthetic techniques including regional analgesia may be used successfully in these patients caution with most drugs, especially pethidine, phenoperidine, suxamethonium and all non-depolarising neuromuscular relaxants is recommended. Of the volatile anaesthetics currently available, halothane is the agent of choice. Oxygen therapy and close monitoring of cardiorespiratory function are necessary postoperatively.

Renal function and fluoride formation and excretion during enflurane anaesthesia

Central circulation, renal function, and fluoride formation and excretion were studied in nine patients during enflurane anaesthesia and surgery. Cardiac output and mean systemic arterial pressure remained unchanged compared with preoperative control values. During anaesthesia and surgery, urine flow rate, inulin clearance, PAH clearance and fractional sodium excretion were 60, 65, 55, and 45% of control values, respectively. Mean peak plasma level of fluoride was 20.0 microM. It was reached 4 hours after termination of anaesthesia. Fluoride clearance (CF) decreased from 23.9 ml . min-1 to 2.7 ml . min-1 during anaesthesia. Postoperative, CF increased to 41.6 and 76.0 ml . min-1, respectively, during two consecutive measurement periods. There was no correlation between plasma fluoride levels and depression of any renal function variable.

Antidiuretic effect of morphine in the rat: tolerance and physical dependence

1 Injection of rats with morphine or methadone, before they received a water load equivalent to 5% of their body weight, produced a dose-dependent antidiuretic effect. Following the antidiuresis, urine was eliminated with kinetics similar to control untreated rats. 2 The antidiuretic effect of morphine or methadone was blocked by naloxone administered before the opiate, or reversed when given after the opiate. 3 Rats implanted with morphine pellets developed a marked degree of tolerance to the antidiuretic effect of morphine. Tolerance was also obtained on injection of three daily doses of morphine or methadone over two days. 4 Withdrawal symptoms were precipitated by naloxone in rats implanted with pellets of morphine; under these conditions the animals showed a marked reduction in urine production as compared to naive rats.

betah-endorphin: antidiuretic effects in rats

Human beta-endorphin (betah-EP) inhibits urine flow in rats. This antidiuretic effect of the peptide occurs after intravenous and intraventricular injections. Intravenously, betah-EP is 24 times more potent than morphine. Intraventricularly, betah-EP is 24 times more potent than morphine. Intraventricularly, betah-EP is effective at doses (0.45 microgram) which have no antidiuretic activity when injected intravenously. This fact suggests that one site of the antidiuretic action of betah-endorphin may be in the central nervous system. Animals tolerant to morphine are also tolerant to the antidiuretic effects of betah-endorphin.

Renal function during neurolept anaesthesia

Renal function and central haemodynamics were studied in eight patients, without known histories of renal or cardiovascular disease, during and immediately after upper abdominal surgery under neurolept anaesthesia. Inulin and PAH clearance, fractional sodium and fractional osmolar excretion decreased, while fractional free water reabsorption increased under anaesthesia. Cardiac output, mean systemic arterial pressure and systemic vascular resistance remained virtually unchanged both per- and postoperatively. Renal haemodynamics were promptly restored postoperatively, while fractional sodium and fractional osmolal excretion were unaltered and antidiuresis increased. It is concluded that neurolept anaesthesia, as far as renal function is concerned, is well suited for the anaesthetic management of the poor-risk patient.

Glomerular filtration rate during halothane anaesthesia and epidural analgesia in combination with halothane anaesthesia

Pre- and peroperative determination of glomerular filtration rate (GFR) was performed in nine patients operated during light halothane anaesthesia (group A) and in nine patients operated during epidural analgesia in combination with light halothane anaesthesia (group B). In group A, the mean GFR decreased insignificantly by 7% and the mean arterial blood pressure increased significantly by 10%. In group B, the mean GFR decreased significantly by 19% and the mean arterial blood pressure decreased significantly by 15%. It is suggested that the difference in change in GFR between the two groups was caused by differences in mean arterial blood pressure.

Radioimmunoassay of antidiuretic hormone during morphine anaesthesia

The effect of morphine anaesthesia on plasma antidiuretic hormone levels was studied in seven adult patients. Measurements of ADH showed no significant change with morphine and 50 per cent nitrous oxide. Significant elevation occurred with surgical stimulation as previously reported. Changes in urine flow with high doses of morphine are then not ADH related.

The role of angiotensin in the canine renal vascular response to barbiturate anesthesia

The influence of barbiturate anesthesia on renal blood flow was assessed by the xenon washout method in trained dogs with catheters chronically implanted in the renal artery. Anesthesia induced with either thiopental sodium or pentobarbital sodium resulted in a striking reduction in renal blood flow (4.1 +/- 0.1 vs. 2.6 +/- 0.2 ml/g per min; P less than 0.001) without a change in arterial pressure. The reduction in blood flow was prevented by a high salt intake and partially reversed by agents which interrupt the renin-angiotensin system (BPF 9a; 1-Sar,8-Ala-angiotensin II; propranolol) but not by alpha-adrenergic blocking agents (phentolamine and phenoxybenzamine). Anesthesia blunted the renal vascular response to angiotensin II (P less than 0.0005) whereas responsiveness to norepinephrine was increased (P less than 0.05). We conclude that barbiturate anesthesia induces a major, angiotensin-mediated renal vascular response which must be considered in the interpretation of experiments performed under these conditions.

Anaesthetic considerations in chronic renal failure

This paper discusses the anaesthetic problems presented by patients in chronic renal failure. The anaesthetic agents and techniques used in 181 patients who underwent 941 operations (including 218 renal transplants) are described.

Effects of anesthetics on the kidney

All general anesthetics employed clinically have significant and reversible effects on renal hemodynamics, water, and electrolyte excretion at concentrations in which they are usually employed for surgical anesthesia. Some of the mechanisms by which these effects are produced are discussed. The minmal depressant effect on renal function of epidural anesthesia is possibly related to local anesthetic effects on the central system and/or the kidney. Methoxyflurane has been demonstrated to produce renal dysfunction when administered in high concentrations for prolonged periods of time to obese patients. Metabolites of methosyflurane including fluoride and/or oxalate appear to be the cause of this problem. Problems of anesthetic management in patients with renal failure have been briefly summarized with specific attention to the undersirable effects of some neuromuscular blocking drugs.

Renal response to chronic intravenous salt loading in the rat

The natriuresis of acute Ringer's loading is associated with a rise in the rate of delivery of fluid beyond the proximal tubule due both to a rise in glomerular filtration and a fall in absolute reabsorption, the latter being causally mediated, at least in part, by the accompanying fall in postglomerular vascular [protein]. To determine whether these factors also contribute to the renal response to chronic Ringer's loading, nine rats given continuous infusions, 30% body weight/day over 5-14 days, were studied using free-flow micro-puncture techniques. Results were compared with data from 10 chronic control rats given less than 1.5% body wt/day. Late proximal tubule fluid-to-plasma [inulin] ratios, (TF/P)(IN), single nephron glomerular filtration rate (SNGFR), absolute proximal reabsorption, and postglomerular vascular [protein] in chronic control rats and chronically loaded rats averaged 2.2+/-SE 0.1 (n = 35) and 1.5+/-0 (35), P<0.001; 37+/-2 (35) and 47+/-4 nl/min (35), P<0.05; 19+/-1 (35) and 16+/-2 nl/min (35), P>0.2; and 9.5+/-0.3 (8) and 8.6+/-0.3 g/100 ml (8), P>0.05, respectively. Thus the fall in (TF/P)(IN) and the rise in distal delivery during chronic Ringer's loading were due almost entirely to the rise in SNGFR, and not to any large fall in absolute reabsorption. Hence chronic and acute Ringer's loading increase delivery of proximal tubule fluid by different mechanisms, with chronic sodium homeostasis being governed overwhelmingly by adjustments in GFR. When, however, an acute Ringer's load was infused into chronically loaded rats, we observed significant and parallel reductions in absolute proximal reabsorption and postglomerular vascular [protein]. These findings suggest that the difference between the effects of chronic vs. acute Ringer's loading on absolute proximal reabsorption may have been due, at least in part, to the corresponding difference in the effects these two loading procedures have on postglomerular vascular [protein].