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PubMed1995

Hyperkalaemia associated with haemorrhagic shock in rabbits: modification by succinylcholine, vecuronium and blood transfusion.

In haemorrhagic patients, hyperkalaemia may occur after succinylcholine administration. We investigated in haemorrhagic rabbits whether vecuronium caused hyperkalaemia and if blood transfusion prevented succinylcholine-induced hyperkalaemia. Rabbits were lightly anaesthetized with halothane/N2O and 30-35 ml/kg blood were withdrawn to cause arterial pH to decrease to approximately 7.0-7.1. Group C (n = 12) received 3 ml saline, Group S (n = 13) received succinylcholine 1 mg/kg, Group V (n = 7) received vecuronium 0.25 mg/kg and Group T (n = 9) was transfused with 10 ml/kg blood 10 min prior to receiving succinylcholine 1 mg/kg. K+ analysis was repeated at 5 min, and at 10 min in most animals. Haemorrhage increased K+ (nmol.1-1, mean +/- SD): Group C, 3.4 +/- 0.3 to 6.8 +/- 1.8; Group S, 3.8 +/- 0.5 to 6.9 +/- 2.3; Group V, 3.8 +/- 0.3 to 7.1 +/- 1.9; Group T, 3.6 +/- 0.5 to 7.6 +/- 2.9. K+ decreased in Group T (to 5.4 +/- 1.8) after blood transfusion. K+ increased at 5 min in Group S (to 8.7 +/- 2.6) and at 10 min for Group C (to 8.4 +/- 1.7) and Group T (to 7.2 +/- 2.3). The K+ increase at 5 min for Group S (1.8 +/- 0.8) was significantly higher than those for Group C (1.0 +/- 0.6) or Group V (0.9 +/- 0.4), but was not different from that of Group T (1.5 +/- 0.7). We conclude that haemorrhage and succinylcholine cause hyperkalaemia in rabbits. Muscle relaxation itself does not appear to be a factor, but transfusion may lessen the hyperkalaemia.

Animals↗

PubMed2002

Are intubation conditions using rocuronium equivalent to those using succinylcholine?

OBJECTIVE: To determine whether the intubation conditions created by rocuronium are equivalent to those of succinylcholine during rapid-sequence induction (RSI). METHODS: Medline, EMBASE, and the Cochrane Controlled Trials Register were searched for randomized clinical trials (RCTs). The search strategy included all generic and trade names for succinylcholine and rocuronium, anesthesia, neuromuscular blockade, and a validated RCT filter. Intubation conditions were a required outcome. Two reviewers assessed studies for eligibility, data extraction, and quality. Intubation conditions were scored with Goldberg's scale (excellent conditions defined as clear vocal cords, easy tube insertion, and no cough). A-priori subgroup analysis was conducted for the sedative, use of opioids, true versus modified RSI, age group, and the dose of rocuronium. Data were analyzed with Metaview 4.1 for relative risk (RR) of achieving excellent intubation conditions. A sample size calculation determined that n = 468 is required for equivalence. RESULTS: Forty articles were identified; ten articles were excluded by the inclusion criteria, two were duplicate publications, and two had insufficient data. Therefore, 26 studies were analyzed. Overall, rocuronium was inferior to succinylcholine, with a RR = 0.87 (95% CI = 0.81 to 0.94) (N = 1,606). However, intubation conditions were similar in the propofol subgroup, with a RR = 0.96 (95% CI = 0.87 to 1.06) (N = 640). Failed intubations (N = 28) were equivalent in the two groups. CONCLUSIONS: Overall, succinylcholine creates excellent intubation conditions more reliably than rocuronium. If a second-line agent is required, rocuronium used with propofol creates intubation conditions equivalent to those with succinylcholine.

Adult↗

PubMed1993

Time course of action and endotracheal intubating conditions of Org 9487, a new short-acting steroidal muscle relaxant; a comparison with succinylcholine.

In a randomized study, we evaluated lag time (time from the end of injection of muscle relaxant until the first depression of the train-of-four response [TOF]), onset time (time from the end of injection of muscle relaxant until the maximum depression of the first twitch of the TOF [T1]), neuromuscular block, and endotracheal intubating conditions at 1 min after 1 mg/kg succinylcholine (n = 15) and 1.5 mg/kg Org 9487 (n = 30). Two minutes after administration of Org 9487, 15 of the 30 patients received neostigmine for reversal. Recovery of neuromuscular block after succinylcholine, Org 9487 without and Org 9487 with neostigmine were compared using the time until T1 was 90% for the succinylcholine group, and the time until TOF was 70% for the Org 9487 groups. Neuromuscular transmission was monitored mechanomyographically. Onset time was similar (67 [20] and 83 [38] s for succinylcholine and Org 9487, respectively) and endotracheal intubating conditions were also similar after both muscle relaxants. Times until clinically sufficient recovery of neuromuscular block induced by succinylcholine (time until T1 = 90%: 10.6 [3.3] min) and Org 9487 with neostigmine (time until TOF = 70%: 11.6 [1.4] min) were not different. In contrast, in the Org 9487 without neostigmine group, more time was required until complete recovery (24.1 [6.2] min) (P < 0.05). In conclusion, ORg 9487 is a muscle relaxant suitable for endotracheal intubation and short-lasting interventions.

Adult↗

PubMed1999

An intrasubject comparison of two doses of succinylcholine in modified electroconvulsive therapy.

UNLABELLED: The electroconvulsive therapy (ECT) guideline of the Royal College of Psychiatrists recommends a 0.5 mg/kg of succinylcholine for ECT modification. Our clinical experience suggests that this dose is insufficient for Indian patients. The dose recommended by the Royal College of Psychiatrists (0.5 mg/kg) and a larger dose (1 mg/kg) were compared in 50 patients referred for ECT. In one ECT session, patients were equally randomized to receive one of the two doses and in the next session they were switched to the other dose. The extent of motor seizure modification was rated on a five-point scale by two independent raters who were blinded to the succinylcholine dose. The interrater reliability was good (K = 0.85). "Poor" seizure modification occurred in 48% and 12% of patients with the 0.5 and 1 mg/kg doses, respectively. Of the 24 patients who had poor modification with 0.5 mg/kg, 20 had "good" modification in the session with 1 mg/kg (P < 0.001). A small delay (mean = 55 s) occurred in time to recover from the respiratory paralysis with the 1 mg/kg dose of succinylcholine. No patient, however, had prolonged apnea requiring special measures. We recommend 1 mg/kg of succinylcholine dose be used in the first ECT session. For subsequent sessions, the dose may be altered, depending on the response for optimal motor seizure modification. IMPLICATIONS: The dose of muscle relaxant (succinylcholine) recommended in modified electroconvulsive therapy is not based on empirical research. In the same patients (n = 50), two doses-0.5 mg/kg and 1 mg/kg-were compared during different electroconvulsive therapy sessions. The larger dose was more effective in modifying the peripheral convulsion.

Adult↗

PubMed2002

Can lidocaine reduce succinylcholine induced postoperative myalgia?

This study was undertaken to determine the effect of lidocaine pretreatment on reduction of succinylcholine-induced myalgia in patients undergoing general anesthesia for gynecological surgery. One hundred and thirty-five patients were assigned to one of three groups in a prospective, double blind, randomized manner. Group PS, the control group, received normal saline and succinylcholine 1.5 mg x kg(-1); Group LS, lidocaine 1.5 mg x kg(-1) and succinylcholine 1.5 mg x kg(-1); Group PR, normal saline and rocuronium 0.6 mg x kg(-1). Morphine 0.1 mg x kg(-1) iv was given for premedication and all patients were monitored with a noninvasive blood pressure monitor, ECG and pulse oximetry. Anesthesia was induced with 5 mg.kg(-1) thiopental iv. followed by succinylcholine (Group PS, LS) or rocuronium (Group PR) for tracheal intubation. Following administration of these agents, the presence, and degree of fasciculation were assessed visually on a four point scale by one investigator who was blinded to the drug administered. The blood pressure and heart rate of each patient were monitored on nine occasions. Twenty-four hours later, any myalgia experienced was assessed according to a structured questionaire and graded by a four point scale by one investigator blinded to the intraoperative management. The results indicate that muscle fasciculation was not found in Group PR while the patients in Group LS had a lower incidence of muscle fasciculation than those in Group PS (p < 0.001). At 24 h, the incidence of myalgia was higher in Group PS than in Group LS and PR (p < 0.05). A correlation was not found between the incidence of myalgia and the occurrence of muscle fasciculation. The changes in systolic and diastolic blood pressure and heart rate were not significant among the three groups. In conclusion, where succinylcholine is used, lidocaine is proven to be the useful pretreatment agent for the reduction of postoperative myalgia.

Adolescent↗

PubMed2004

Improving the success rate of laryngeal mask airway insertion during etomidate induction by using fentanyl or succinylcholine.

BACKGROUND: Smooth and successful insertion of a laryngeal mask airway (LMA) during etomidate induction requires a proper mouth opening and efforts to minimize airway reflexes such as gagging, coughing, or laryngospasm. We hypothesized that the concurrent use of fentanyl or succinylcholine with etomidate, the induction agent, could reduce the occurrence of airway reflexes and increase the success rate of LMA. METHODS: Sixty adult patients, ASA class I-II, scheduled for surgery under general anesthesia, were randomly allocated into three groups: group I in which patients were given etomidate 0.3 mg/kg alone; group 2 in which patients were given fentanyl 2 microg/kg and etomidate 0.3 mg/kg; groups 3 in which patients were give etomidate 0.3 mg/kg and succinylcholine 1 mg/kg. All patients were premedicated with atropine 0.01 mg/kg. When induction of anesthesia began we recorded the time from administering the designated regiminal agent or agents to the time of relaxation of jaw (the ease of mouth opening) and checked the patient for any excitatory movement after administering the induction agents. After inserting the LMA, we checked for signs of airway reflexes. Student's t test, Chi-square and Fisher's exact test were used to analyze the data. A value of P < 0.05 was considered significant. RESULTS: There were no significant differences in demographic data among the the three groups. The concurrent use of fentanyl or succinylcholine with etomidate during induction could significantly reduce the occurrence of excitatory movements and airway reflexes after LMA insertion, and increase the success rate of LMA insertion in comparison with using etomidate alone. Comparing the two adjutant agents, the concurrent use of succinylcholine could provide a significantly better jaw relaxation, shorten the time to insert the LMA and increase the success rate of LMA insertion. CONCLUSIONS: As an induction agent to facilitate insertion of LMA, etomidate alone was far from perfect. The concurrent use of 2 microg/kg of fentanyl with etomidate might significantly reduce the occurrence of airway reflexes in response to LMA insertion and increase the success rate of insertion. However, concurrent use of 1 mg/kg succinylcholine with etomidate might provide better results in terms of shortened time for the LMA insertion, jaw relaxation, and the success rate of LMA insertion than that of fentanyl.

Adult↗

PubMed1991

[Effect of succinylcholine on recovery of atracurium-induced neuromuscular blockade].

If muscle relaxation is inadequate at the end of surgery, a transient increase in neuromuscular (NM) blockade should be needed to facilitate closure. Succinylcholine is the only agent of short duration available currently and could be used in the just mentioned circumstance. Therefore, the study was designed to investigate the effects of succinylcholine on the recovery of atracurium-induced NM blockade. Sixty-four female patients who underwent elective surgery under general anesthesia were allocated into 6 groups. Before anesthesia, no patient had received drugs which affect NM transmission. In all patients anesthesia was induced with thiopental, diazepam and fentanyl and maintained with 50% nitrous oxide in oxygen and 0.5-1.5% isoflurane. During anesthesia, blood pressure and electrocardiogram were monitored and end-tidal CO2 was maintained at 30-40 mmHg. Control records of the integrated electromyography responded to train-of-four supramaximal stimulation using a Datex Relaxograph were obtained after induction of anesthesia before a block was produced with an initial dose of succinylcholine 1.0 mg in group I (n = 8) or atracurium 0.4 mg/kg in groups II-VI. On first twitch (T1) recovering to 50% of control, 0.4 mg/kg, 0.6 mg/kg, 0.8 mg/kg, 1.0 mg/kg and 1.2 mg/kg of succinylcholine were given in groups II (n = 11), III (n = 14), IV (n = 11), V (n = 10), VI (n = 10) respectively. It was seen that succinylcholine 0.4 mg/kg antagonized NM blockade by atracurium but at 0.6 mg/kg, 0.8 mg/kg, 1.0 mg/kg, 1.2 mg/kg it enhanced that.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Stability of succinylcholine chloride injection.

The stability of succinylcholine chloride injection prepared by a hospital pharmacy was studied under a wide variety of conditions. Batches of succinylcholine chloride injection 10 mg/mL containing sodium chloride, methyl-4-hydroxybenzoate, hydrochloric acid, and water were prepared. Samples were tested for the effect of initial pH (3.0 and 4.2) and sterilization (steam treatment at 100 degrees C for 30 minutes and 121 degrees C for 20 minutes) on stability after three weeks; long-term stability under refrigeration (12, 17, and 23 months of storage at 4 degrees C); and the effect of storage temperature (4-6 degrees C, 20-26 degrees C, 35 degrees C, and 70 degrees C) and light exposure at various intervals up to 12 months. Samples were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Unlike heating at 121 degrees C, heating at 100 degrees C produced no significant loss of succinylcholine chloride, independent of the initial pH. Succinylcholine chloride was hydrolyzed only minimally over 23 months if the solution was stored at 4-6 degrees C. A 10% loss of drug content occurred if solutions were kept at 20-26 degrees C for five months, at 35 degrees C for one month, or at 70 degrees C for one day. Initial degradation was slowed if the solution was protected from light. The assessments by TLC proved to be more sensitive than the HPLC measurements. Succinylcholine chloride injection sterilized at 100 degrees C for 30 minutes can be stored for up to five months at room temperature if protected from light. The preparation is stable for at least two years under refrigeration.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Comparative trial of succinylcholine vs low dose atracurium-lidocaine combination for intubation in short outpatient procedures.

Despite its many disadvantages, succinylcholine is the most commonly used drug for intubation of patients for short out-patient procedure. This double blind trial compared a low dose atracurium/lidocaine combination to succinylcholine for intubation in 40 ASA1 adult patients. Low dose atracurium/lidocaine provided clinical intubating conditions at two minutes and cardiovascular stability equivalent to succinylcholine with significantly less myalgia. Spontaneous respiration was slower after low dose atracurium/lidocaine relative to succinylcholine. Low dose atracurium/lidocaine may provide an acceptable alternative to succinylcholine for intubation in short outpatient procedures.

Adult↗

PubMed1988

Potency of succinylcholine at the diaphragm and at the adductor pollicis muscle.

To quantify the differential effect of succinylcholine at the diaphragm and the adductor pollicis muscle, 10 patients were studied during halothane-nitrous oxide anesthesia. Train-of-four stimulation was applied to the ulnar and phrenic nerves. The force of contraction and the electromyographic response of the adductor pollicis were measured and compared with the diaphragmatic electromyogram. Then dose-response curves for both muscles were constructed using incremental doses of succinylcholine with an infusion to replace metabolized or redistributing drug. Linear regressions were obtained between the logit transformation of neuromuscular blockade at the adductor pollicis and diaphragm and the logarithm of the dose. The diaphragm was relatively resistant to succinylcholine. At 90% adductor pollicis block, the diaphragm was only (mean +/- SEM) 37 +/- 3% blocked. The diaphragm required 1.8 +/- 0.2 times as much succinylcholine as the adductor pollicis for an identical 90% block. The ED50 and ED90 values for succinylcholine at the diaphragm were 0.23 +/- 0.04 and 0.40 +/- 0.09 mg/kg, respectively. Corresponding values for the adductor pollicis were 0.14 +/- 0.01 and 0.21 +/- 0.02 mg/kg. The data indicate that the degree of adductor pollicis blockade might overestimate the intensity of diaphragmatic paralysis.

Anesthesia, Inhalation↗

PubMed1986

Changes in heart rate and rhythm after intramuscular succinylcholine with or without atropine in anesthetized children.

The effects of intramuscular injections of succinylcholine with or without atropine on heart rate and rhythm were studied in 50 unpremedicated children 6-18 months of age. All had anesthesia induced with N2O-O2 and halothane 2% by face mask. Sixty seconds later, one of four study drugs or drug combinations was injected into the deltoid muscle of patients in groups 1-4. Following injection, halothane concentration was reduced to 1%, and ventilation was controlled. Patients given atropine only (0.02 mg/kg), succinylcholine only (4 mg/kg), or a combination of both (4 mg/kg succinylcholine plus 0.02 mg/kg atropine) showed transient increases in heart rate to 106 +/- 7.5%, 113 +/- 11.8%, and 109 +/- 10.1% (mean +/- SD) of control, followed by a decrease to 78 +/- 6.7%, 79 +/- 9.4%, and 80 +/- 10.5%, respectively, in 2-3 min after injection. Patients given a combination of succinylcholine (4 mg/kg) plus a higher dose of atropine (0.03 mg/kg) also had a transient increase in heart rate to 107 +/- 7.5%, followed by a decrease to 82 +/- 11.8% 2 min after injection. However, this group differed from the other three groups in presenting a second, prolonged increase in heart rate to 115 +/- 9.0% of preinjection levels. Patients in group 5 (controls) received no injections. Their heart rate decreased to 76 +/- 10.78% of preinduction level within 90 sec of induction, and remained unchanged thereafter. We conclude that succinylcholine (4 mg/kg) can be used intramuscularly with or without atropine (0.02 mg/kg) in lightly anesthetized young children without producing severe bradycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗

PubMed1985

Flunitrazepam prevents succinylcholine-induced increase in intra-ocular pressure.

Ninety-three patients scheduled for various elective surgical procedures were divided into three equal groups and had induction of anaesthesia with either thiopentone (5 mg/kg), thiopentone (5 mg/kg) plus gallamine (0.3 mg/kg), or with flunitrazepam (0.03 mg/kg). Four minutes after induction they received a bolus intravenous injection of succinylcholine (1 mg/kg). Intra-ocular pressure was measured before and after induction, and approximately 1 minute after succinylcholine. It was found that flunitrazepam prevented the increase in intra-ocular pressure better than thiopentone plus gallamine. In both these groups, the subsequent intravenous administration of succinylcholine slightly increased the pressure but to levels below that noted before anaesthesia was induced. However, intra-ocular pressure was significantly increased above baseline levels when succinylcholine was injected after induction with thiopentone alone. Flunitrazepam is recommended, therefore, as a possible alternative for thiopentone-gallamine induction with succinylcholine when an increase in intra-ocular pressure must be prevented.

Adolescent↗

PubMed1979

Succinylcholine drug interactions during electroconvulsive therapy.

Electroconvulsive therapy (ECT) is frequently described as being almost free of absolute contraindications. However, drug interactions with succinylcholine pose potential hazards to which this paper calls attention. In addition to its neuromuscular-blocking action, succinylcholine has other acetylcholine-like effects. Drugs which inhibit cholinesterase activity or which inhibit acetylcholine release or synthesis may produce prolonged respiratory paralysis when combined with succinylcholine. The increasing longevity of the population receiving chemotherapy for physical ailments implies that greater numbers of these patients may also become candidates for ECT and therefore be at risk for adverse drug interactions with succinylcholine. Of particular importance to the psychiatrist are the various psychotropic drugs that have been reported to interact with succinylcholine. Precautions in using drug combinations and treatment of complications are described.

Animals↗

PubMed1983

Calcium gluconate pretreatment for prevention of succinylcholine-induced myalgia.

The effects of calcium gluconate pretreatment on succinylcholine-induced postoperative muscle pain and on the changes in serum potassium and calcium levels were studied in 80 patients undergoing elective surgery who were to become ambulatory on the same evening. A test group of 40 patients was given 10 ml of 10% calcium gluconate intravenously immediately before induction of anesthesia with thiopental followed by succinylcholine for tracheal intubation. A control group of 40 patients was given thiopental and succinylcholine without calcium gluconate. Muscle pains were graded according to severity as nil, mild, moderate, and severe. The incidence of postoperative muscle pains was significantly less (5%) in the test group than in the control group (45%). In control patients who subsequently developed muscle pain, serum levels of potassium were significantly increased above preinduction levels 2 min after succinylcholine was administered and serum calcium levels were significantly decreased. In control patients who did not develop postoperative myalgia, there were no significant changes in serum levels of either calcium or potassium. This was also true for patients pretreated with calcium gluconate. Therefore, calcium gluconate pretreatment reduces both the increase in serum potassium and the decrease in serum calcium associated with succinylcholine, and decreases the incidence and severity of postoperative myalgia.

Adolescent↗

PubMed1982

Plasma cholinesterase activity and tachyphylaxis during prolonged succinylcholine infusion.

Fifteen patients were studied during general anesthesia (nitrous oxide-fentanyl, N = 7 or nitrous oxide-isoflurane, N = 8) to determine the relationship between plasma cholinesterase activity and succinylcholine requirements during prolonged infusion. Using train-of-four stimulation, neuromuscular block was maintained at 90% for at least 1 hour, and plasma cholinesterase was measured at 30-minute intervals. During the infusion, succinylcholine requirements increased in every patient (tachyphylaxis), but there was no significant change in plasma cholinesterase activity. Succinylcholine requirements during the 1st hour of infusion in patients given fentanyl were correlated with preinfusion cholinesterase activity. It is concluded that tachyphylaxis to succinylcholine is not the result of increased metabolism from enzyme induction and that succinylcholine requirement is related to plasma cholinesterase activity.

Cholinesterases↗

PubMed1994

Effects of magnesium sulfate pretreatment on succinylcholine-facilitated tracheal intubation.

Magnesium sulfate may prevent increase in serum potassium produced by succinylcholine and cause transient hypotension. The present study was designed to evaluate the effect of magnesium sulfate on heart rate, blood pressure and hyperkalemic response following succinylcholine injection during tracheal intubation. Twenty patients, ASA class I-II, scheduled for elective surgery were equally and randomly allocated to two groups. Heart rate, blood pressure, venous and arterial potassium levels were measured immediately before intubation. Induction was achieved with fentanyl 2 ug/kg and thiopental 5 mg/kg i.v., and intubation was facilitated with succinylcholine 1.0 mg/kg i.v. In the magnesium group (group I), 60 mg/kg of magnesium sulfate was infused intravenously in 1-1.5 min immediately before succinylcholine injection. The control group (group II) received an equal volume of normal saline in the same way. Heart rate, blood pressure, venous and arterial potassium levels were measured at 1, 3, 5 and 10 minutes after intubation. The results showed that magnesium sulfate could attenuate the hypertensive response at 1 minute and the hyperkalemic response at 1 and 3 minutes following succinylcholine-facilitated intubation; the tachycardiac response at 1 minute after intubation could not be reduced by this agent. We concluded that bolus infusion of magnesium sulfate may be of help in reducing the hypertensive response during laryngoscopy and intubation.

Adult↗

PubMed1993

Oral clonidine premedication prevents the rise in intraocular pressure following succinylcholine administration.

The objective of the study was to assess the effects of premedication with clonidine on intraocular pressure (IOP) after the administration of succinylcholine. Fifty elderly patients undergoing ophthalmic surgery were randomly allocated to two study groups. Group 1 patients (n = 25) received clonidine, 300 micrograms p.o. In group 2 (n = 25), the benzodiazepine dipotassium clorazepate was given p.o. at a dose of 0.3 mg.kg-1. Anesthesia was induced with thiopental 3-4 mg.kg-1, alfentanil 10 micrograms.kg-1, atracurium 0.07 mg.kg-1, and succinylcholine 1 mg.kg-1. Nine IOP measurements were taken in each patient starting before premedication and ending 3 min after endotracheal intubation. In both groups, there was a decrease in IOP after induction of anesthesia with thiopental and alfentanil. Succinylcholine administration and endotracheal intubation had no further effect on IOP in the clonidine group. In group 2, succinylcholine caused an increase in IOP when compared with the post induction value. We conclude that clonidine premedication can prevent the increase in IOP following succinylcholine administration.

Administration, Oral↗

PubMed1996

[Succinylcholine induces hyperpotassemia in patients in critically ill patients].

OBJECTIVE: To study changes in kalemia caused by succinylcholine administration to patients in critical care, and the possible association of succinylcholine with clinical and analytical data, severity-of-disease classification, duration of stay in the intensive care unit (ICU) and immobility. PATIENTS AND METHODS: Twenty-three patients admitted to the ICU, none of whom suffered burns, polytrauma or neuromuscular disease, and who had received 1.5 mg/kg succinylcholine on 28 occasions, usually to facilitate tracheal intubation. Kalemia was analyzed before neuromuscular relaxation and 5 and 30 min afterwards. Electrocardiographic II and V5 derivations and invasive arterial pressure were monitored in all patients. The increase in kalemia at 5 min correlated with age, sex, weight, APACHE II score, days in ICU, current and accumulated immobility, and analytical parameters such as glycemia, creatinine, GOT, bilirubinemia, pH and creatine kinase. The kalemia of these patients was compared with that of 15 patients in acceptable general state who had undergone scheduled surgery. RESULTS: Kalemia increased significantly from a mean baseline level of 4.2 (0.9) mEq/l to 5.5 (1.4) at 5 min and 4.6 (0.9) at 30 min in ICU patients. In the non ICU patients there were no statistically significant changes. Kalemia at 5 min was correlated with baseline (r = 0.84; p < 0.0001), days in the ICU (r = 0.39; p < 0.05) and weight (r = 0.46; p < 0.05). The mean increase in kalemia at 5 min was 0.5 mEq/l in patients who stayed less than 10 days, 1.8 mEq/l in those whose stay was from 10 to 30 days and 1.4 mEq/l in patients who stayed longer than 30 days. The percent increase in kalemia correlated directly (r = 0.7; p < 0.001) with days in the ICU and with accumulated immobility in patients whose ICU stay was less than 30 days. For ICU stays longer than 30 days the correlation was negative (r = -0.98; p = 0.03). Electrocardiographic changes were recorded in 2 patients with brief sinus bradycardia having no hemodynamic repercussions. CONCLUSIONS: The use of succinylcholine in critically ill patients causes a brief but significant increase in kalemia, with slight and rare electrocardiographic changes. The effect varies according to the length of time spent in the ICU and the degree of immobility, with maximum increases seen when the ICU stay is between 10 and 30 days. Patient immobility may play an important pathophysiological role. The indications for use of succinylcholine in critically ill patients should be very strict, particularly during the period of greatest sensitivity.

Adult↗