Compliance with triage to intensive care recommendations

DESIGN

Recommendations for triage to intensive care units (ICUs) have been issued but not evaluated.

SETTING

In this prospective, multicenter study, all patients granted or refused admission to 26 ICUs affiliated with the French Society for Critical Care were included during a 1-month period. Characteristics of participating ICUs and patients, circumstances of triage, and description of the triage decision with particular attention to compliance with published recommendations were recorded.

RESULTS

During the study period, 1,009 patients were and 283 were not admitted to the participating ICUs. Refused patients were more likely to be older than 65 yrs (odds ratio [OR], 3.53; confidence interval [CI], 1.98-5.32) and to have a poor chronic health status (OR, 3.09; CI, 2.05-4.67). An admission diagnosis of acute respiratory or renal failure, shock, or coma was associated with admission, whereas chronic severe respiratory and heart failure or metastatic disease without hope of remission were associated with refusal (OR, 2.24; CI, 1.38-3.64). Only four (range, 0-8) of the 20 recommendations for triage to ICU were observed; a full unit and triage over the phone were associated with significantly poorer compliance with recommendations (0 [0-2] vs. 6 [2-9], p =.0003; and 1 [0-6] vs. 6 [1-9], p <.0001; respectively).

CONCLUSION

Recommendations for triage to intensive care are rarely observed, particularly when the unit is full or triage is done over the phone. These recommendations may need to be redesigned to improve their practicability under real-life conditions, with special attention to phone triage and triaging to a full unit.

Long- and medium-chain triglycerides during parenteral nutrition in critically ill patients

Due to their special metabolic pathway, medium-chain triglycerides (MCT) have been claimed to be oxidized more extensively, compared with long-chain triglycerides (LCT), when administered as a parenteral nutritional support. This enhanced lipid oxidation rate of MCT emulsions could be particularly disclosed in hyperglycemic and hyperinsulinemic conditions. In an attempt to further elucidate this question, we measured substrate oxidation rates in critically ill patients liable to experience such metabolic conditions, that is to say postoperative patients after esophageal resection receiving 1.5 times their measured energy expenditure (n = 12) or after liver transplantation (n = 8). These patients received either LCT or MCT-LCT emulsions. The metabolic measurements were performed simultaneously by two methods, namely indirect calorimetry and isotopic methods based on natural abundance of nutrients. Although both groups of patients were hyperglycemic and hyperinsulinemic, the measured carbohydrate and lipid oxidation rates were not different with whatever type of lipid was administered. The MCT-LCT emulsions did not offer clear-cut advantages over LCT emulsions in critically ill patients when lipid energetic fate was considered.

Clinical validation of the Deltatrac monitoring system in mechanically ventilated patients

OBJECTIVE

To evaluate a monitor of pulmonary gas exchange (Deltatrac, Datex) in a clinical setting.

DESIGN

After in vitro evaluation, comparison over 2 min between VO2 and VCO2 values measured by the Deltatrac and the Douglas bag technique. Comparisons were also achieved over 8 h periods between the Deltatrac and a system using a mass-spectrometer.

SETTING

Polyvalent intensive care unit (ICU 15 beds) in a 1200 bed general hospital.

PATIENTS

Comparison with the Douglas bag technique in 10 patients undergoing controlled ventilation. Comparison with the mass-spectrometer system in 25 other patients undergoing controlled or pressure support ventilation.

MEASUREMENTS AND RESULTS

Compared to the results obtained by the Douglas bag technique, the bias (+/- 2 SD) for VO2 and VCO2 was -3.5 +/- 26.6 and 6.1 +/- 12.7 ml.min-1, respectively. By comparison with the mass-spectrometer system, the bias for VO2 and RQ was -5.8 +/- 16.0 ml.min-1 and 0.018 +/- 0.048, respectively. No drift between the two systems was observed over time.

CONCLUSIONS

The Deltatrac appears suitable for VO2 and VCO2 measurements in ventilated patients and equivalent to a mass-spectrometer system for long term measurements.

Effects of glucose-to-lipid ratio and type of lipid on substrate oxidation rate in patients

This study is an investigation into the effects of different carbohydrate-to-lipid ratios on CO2 production in postoperative patients and the determination of the substrate oxidation rates induced by long-chain triglycerides (LCT) or a mixture of long- and medium-chain triglycerides (MCT/LCT) at various carbohydrate-to-lipid ratios. Two groups of eight patients randomly received either LCT or MCT/LCT emulsions. Total caloric intake was set at the measured energy expenditure provided at three different glucose-to-lipid ratios (70:30, 50:50, 30:70). We used long-term indirect calorimetry with a mass spectrometer system and measurement of natural enrichment in 13C of expired CO2 and plasma glucose. The carbon dioxide production and minute ventilation were not different among the different glucose-to-lipid ratios, whatever the type of lipid. Increasing the lipid supply up to 70% of nonprotein caloric intake led to an only minor increase in lipid oxidation rate and thus to a net fat deposit. We conclude that large amounts of lipid (LCT or MCT/LCT) were not of interest in such patients.

Metabolic effects of hemodialysis with and without glucose in the dialysate

This study was conducted in eight acute renal failure patients undergoing mechanical ventilation to test if the addition of glucose in the dialysate prevents metabolic and hormonal changes induced by hemodialysis. Hemodialysis was performed with a bicarbonate dialysate, a polyacrilonitrile membrane and a continuous heparinization. Two four-hour hemodialysis sessions were performed in each patient: one without glucose (GFD) and one with glucose (GD) in the dialysate at a concentration close to each patient's initial plasma glucose concentration. Oxygen consumption and carbon dioxide elimination, glucose insulin, aceto-acetate and free fatty acids were measured before, during and after the sessions. Oxygen consumption and carbon dioxide elimination were measured with a system using a mass spectrometer. Hemodynamic state and temperature remained constant. Before hemodialysis, respiratory quotient (RQ) values were the same in both groups. There was no change in RQ during GD. There was a decrease in RQ during GFD. Glucose and insulin concentrations decreased during GFD and remained unchanged during GD. Aceto-acetate concentration remained constant under both conditions. Free fatty acids concentration increased to the same extent during GD and GFD. The authors conclude that the addition of glucose in the dialysate prevents the decrease in RQ induced by hemodialysis. This effect is most likely related to a decreased mobilization of non-glucidic fuels.

[Early somatosensory (SEP) and auditory (AEP) evoked potentials in anoxic coma: prognostic value]

Early somatosensory (SEP) and auditory (BAEP) evoked potentials, when recorded within the first seven days of the course of anoxic coma, appear to be reliable to evaluate anoxic ischemic cortical or under-cortical lesions. Prognosis depends especially on cortical SEP (N20-P25): the lack of SEP is a good outcome predictor of death (abnormal BAEP) or of vegetative status (normal BAEP); the presence of normal and bilateral cortical SEP (with normal BAEP) allows to predict awakening, without prejudging of neurologic sequelae, even if they are severe.

Recovery of [13C]bicarbonate as respiratory 13CO2 in mechanically ventilated patients

Measurement of the nutrient oxidation rate with 13C as a tracer requires knowledge of the value of its coefficient of fractional recovery in the expired gas (FR). We measured FR in nine intensive care patients who were mechanically ventilated and received total parenteral nutrition. NaH13CO3 was administered at a priming dose (3.75 mumol.kg-1.min-1) followed by a continuous infusion (0.05 mumol.kg-1.min-1). Metabolic rate and pulmonary carbon dioxide elimination (VCO2) were measured by using a mass-spectrometer system. The 13C-12C ratio was measured in the expired gas with an isotopic-ratio mass spectrometer and FR was calculated by using standard equations. The average value of FR was 0.899 +/- 0.026 (means +/- SE) and remained stable for each patient on 2 consecutive days. Between patients, the coefficient of variation of FR was 8.6%. Metabolic rate was the only physiological factor found to affect the FR value.

[Orthotopic liver transplantation for severe amanita phalloides poisoning]

Forty-eight hours after a women was poisoned by ingesting Amanita phalloides mushrooms, she developed fulminant hepatic failure with collapse, pH 7.24, lactic acidosis 7.6 mmol/l, hypoglycaemia 3.5 mmol/l, anuria and stage IV coma requiring tracheal intubation and mechanical ventilation. Transaminase level was up to 8,000 UI/l. Prothrombin and factor V levels were below 10 percent, with an APT time of 86 s versus a 29 s control time. Twenty-four hours after her admission, the patient underwent orthotopic liver transplantation. The postoperative period was uneventful, with return to consciousness and rapid normalization of hepatic biochemistry values, without signs of acute rejection. This 10th published case of orthotopic liver transplantation for Amanita phalloides poisoning with acute hepatic necrosis confirms that this type of treatment must be systematically envisaged in all such cases.

[Neurological manifestations in the vertebro-basilar system suggesting pregnancy toxemia]

Early CT scan showed a large hypodensity throughout midbrain. Brainstem auditory evoked potential showed initially an abolition of III and V pikes suggesting brainstem injury. Two days later neurologic examination and brain stem auditory evoked potential returned to normal. CT scan performed three weeks after the onset was normal. These finding suggest a vasospasm; in this case betasympathomimetic agents given two weeks before the onset of toxemia for preterm labor could lead to the vasospasm.

The effects of norepinephrine infusion on oxygen consumption in a patient with septic shock

A 65-year-old man developed postsurgical septic shock, unresponsive to plasma volume expansion and administration of dopamine and dobutamine. A continuous norepinephrine infusion was then started and the dose increased to 0.62 micrograms.kg-1.min-1 until the mean arterial pressure was 70 mmHg. Prior to and during the norepinephrine infusion, oxygen consumption was continuously measured with a mass spectrometer system. There was a parallel increase in mean arterial pressure and oxygen consumption (+ 35%). There was also an increase in cardiac index and oxygen delivery. Systemic vascular resistance was only transiently increased. In this case with septic shock, norepinephrine infusion improved hemodynamic variables with an associated increase in oxygen consumption.

[Early somatosensory and auditory evoked potentials in anoxic coma. Role in evaluating and prognostic value]

Early somatosensory (ESEP) and auditory (EAEP) evoked potentials were recorded in 27 patients with severe coma (Glasgow score less than 5) following cardiorespiratory arrest, within the first 7 days of its course. Somatosensory responses were elicited by stimulation of the median nerve. ESEP were abolished in 17 patients due to a parietal thalamo-cortical lesion. Among these, 6 patients died within one month and 11 presented with a persistent vegetative state. In all patients EAEP were obtained, showing functional brainstem activity. Low-voltage EAEP, especially for peak V (inferior colliculus or upper part of the brainstem), was sometimes observed. One patient, in whom ESEP and EAEP were initially abolished, died rapidly. In 9 other patients scalp-recorded ESEP and EAEP were normal; all emerged from coma including 5 with good neurological recovery and 4 with neurological sequelae. Clinical, electroencephalographic and computerized tomographic data appeared to be devoid of predictive value at the same initial period. In view of their sensitivity to anoxia and to cerebral oedema, even with neurosedative drugs, ESEP seemed to be reliable in predicting outcomes and in evaluating central nervous system lesions at cortical and subcortical levels (basal ganglia and brainstem) after cardiorespiratory arrest.

Effects of protein intake on pulmonary gas exchange and ventilatory drive in postoperative patients

The effects of different protein regimens on pulmonary gas exchange and ventilatory drive were examined in eight postoperative patients receiving inspiratory pressure support ventilation. They were studied during 60 consecutive hours, which included two 12-h periods of high protein intake (33%) of total caloric intake provided as protein), each of them being preceded and followed by a 12-h period of standard protein intake (14% of total caloric intake provided as protein). Throughout the study, total caloric intake was 1.5 times the predicted resting energy expenditure. Nitrogen was provided as a 24% branched chain amino acid (BCAA) solution during the period of standard protein intake. During the periods of high protein intake, it was provided as a 24% and a 41% BCAA solution. Pulmonary gas exchange was continuously measured during the second half of each period, with the use of a mass spectrometer system. Measurements of the ventilatory response to CO2 (FICO2 0, 1.5, and 3%) were achieved at the end of each dietary regimen. O2 consumption, CO2 production, respiratory quotient, minute ventilation, and PaCO2 were the same for the three protein regimens. Changing protein intake failed to affect the ventilatory response to CO2. The authors conclude that, in postoperative patients having inspiratory pressure support ventilation, the administration of a high protein intake does not affect the ventilatory drive and the pulmonary gas exchange.

A case of sotalol poisoning with fatal outcome

The case of a 58 year old woman who died after ingestion of 14.4 g of sotalol and 50 mg of triazolam is described. Despite medical treatment, intracardiac pacing and hemodialysis, cardiovascular failure persisted and became irreversible. High sotalol concentrations were observed in plasma (65 micrograms/ml) and in post mortem tissues samples. Tissue to plasma ratios ranged from 2.5 to 6. The high drug concentration found in heart tissue (104.4 micrograms/g) explains the difficulties experienced in the sotalol poisoning.

Energy expenditure in the acute renal failure patient mechanically ventilated

Twenty mechanically ventilated patients with acute renal failure were studied on 31 occasions to determine their energy expenditure (EE) during a 2 h period before a hemodialysis. Oxygen consumption and CO2 elimination were measured continuously with a mass spectrometer system. EE (1660 +/- 48 kcal day-1) was close to the total caloric intake (1682 +/- 83 kcal day-1) and represented 1.19 +/- 0.03 times the predicted resting energy expenditure (PREE) with large inter-individual variations (0.7-1.7 PREE). EE/PREE was higher when sepsis was present (1.31 +/- 0.03 versus 1.14 +/- 0.02; p less than 0.05). Glucose oxidation rate (4.35 mg kg-1 min-1) exceeded glucose intake (2.6 mg kg-1 min-1). Respiratory quotient was 1.02 +/- 0.01. Nitrogen loss was 17.3 +/- 1.7 g day-1 and nitrogen balance -11.9 +/- 1.9 g day-1. In conclusion, EE values were scattered but never exceeded 1.7 times the PREE. Sepsis increased EE. With a nutritional support covering EE, nitrogen balance remained markedly negative and a preferential utilisation of glucose and lipogenesis occurred.

[Myocardial infarction during postoperative peridural analgesia with opiates]

A case of postoperative myocardial infarction is reported. It occurred seven days after intra-abdominal surgery (left hemicolectomy), in a patient with coronary heart disease. Diagnosis was delayed because of lack of pain; it was suggested by cardiogenic shock occurring 48 h after the initial phase. The patient had been receiving postoperative epidural analgesia with an opioid (pethidine); this may explain the pain was missing, so delaying the diagnosis.

[Methanol poisoning]

The neurological signs, the cerebral CAT scan aspects and the ocular problems seen in five cases of acute methanol poisoning are reported; these were, respectively, coma requiring assisted ventilation, convulsions, hypotonicity, hypodensity of the putamen, and amaurosis and papillary oedema. The simplified acute physiologic score varied from 11 to 26; the value of 26 was observed in the only death of the series. Pathogenesis of the metabolic acidosis, as well as the different parts played by formic acid, lactic acid and ketone bodies are discussed. A normal or lowered serum potassium in a case of unexplained metabolic acidosis associated with an osmotic gap should make one think of the diagnosis. Macrocytosis, an indirect sign of folic acid deficiency, was in favour of a poor prognosis. The treatment included early gastric lavage, alkalinization, blocking of the metabolism of methanol by ethanol and haemodialysis with a bicarbonate dialysate enriched in ethanol; this corrected the acidosis and permitted the elimination of the toxic metabolites (clearance of methanol: 159 ml X min-1; half-life of methanol during purification: 3.46 +/- 1.32 h; quantity extracted: 246 g). The possible advantages of 4-methyl-pyrazol and alkyldiol derivatives need further confirmation.

Pulmonary gas exchange during hemodialysis

Pulmonary gas exchange was continuously measured in 13 mechanically ventilated patients during 24 hemodialyses for acute renal failure. Minute-ventilation was maintained constant by controlled ventilation and gas exchange was continuously measured by a mass-spectrometer system. Three groups were compared: a cuprophan membrane with an acetate dialysate; a polyacrilonitrile membrane (PAN) with an acetate dialysate; and PAN with a bicarbonate dialysate. Arterial PO2 and the O2 alveolar-arterial gradient were the same regardless of the membrane used. [H+] mildly decreased with all dialysates used. Arterial PCO2 decreased only with the acetate dialysate. O2 consumption increased, up to 20 +/- 5% of the initial values during hemodialysis, and remained increased during the two hours following the hemodialysis. Respiratory exchange ratio was lower after than before the hemodialysis.

IN CONCLUSION

the maintenance of a constant minute ventilation prevented hemodialysis induced hypoxemia. VO2 increased during hemodialysis.

Deep venous thrombosis with clinical signs after catheterization of the superior vena cava system

This clinical investigation examined deep venous thrombosis with clinical signs indicating superior vena caval involvement, secondary to installation of central venous catheters. Thrombophlebitis was rare, but very dangerous if of septic origin.

Alfentanil pharmacokinetics in patients with cirrhosis

The pharmacokinetics of alfentanil were studied in 11 patients with alcoholic cirrhosis and 10 control patients during general anesthesia. All patients received 50 micrograms . kg-1 alfentanil as an intravenous bolus injection. Plasma concentrations were measured at intervals up to 10 h, using a specific radioimmunoassay technique. Protein binding was measured by equilibrium dialysis. Patients with cirrhosis had a significantly lower (P less than 0.01) plasma clearance of alfentanil of 1.6 +/- 1.0 ml . min-1 . kg-1 (mean +/- SD) instead of 3.1 +/- 1.6 ml . min-1 . kg-1 in the controls. The total apparent volume of distribution was similar in the two groups. The elimination half-life was prolonged from 90 +/- 18 min in the controls to 219 +/- 128 min in the cirrhotics (P less than 0.01). Patients with cirrhosis had a higher (P less than 0.01) alfentanil plasma-free fraction (18.6 +/- 9.4%) compared with the control patients (11.5 +/- 3.9%). When kinetic parameters were corrected for protein binding, the unbound volume of distribution and the free drug clearance were decreased significantly in patients with cirrhosis. Since the concentration alpha 1-glycoprotein to which alfentanil mainly is bound in plasma did not differ in the two groups, it is suggested that the increase in the free fraction is caused by an alteration of binding sites of this protein in patients with cirrhosis. Owing to its delayed elimination and increased free fraction, alfentanil will exert a prolonged and pronounced effect in patients with cirrhosis.

[Acute amiodarone poisoning. Clinical and pharmacokinetic study]

A 73 years old patient, treated with Amiodarone for ventricular tachycardia, ingested 6 000 mg of Amiodarone. This did not induce hemodynamic troubles or aggravation of ventricular arrhythmia. Treatment included a gastric lavage and purging at the third hour. Plasma assay revealed a concentration of 3.69 mg/l at the fourth hour. Their evolution can be described as the sum of two exponentials. The half-life of the first exponential is 4.9 hours ; the half-life of the second one is 544 hours. Amiodarone is an antiarrhythmic agent of high safety.

[Acute water intoxication induced by oxytocin]

A new case of oxytocin-induced water intoxication is reported in a 30 year old gravid woman. The severe symptoms of this uncommon complication are principally neurological; biological signs are a hyponatraemia with low plasma osmolality. Usually, biological and clinical signs are rapidly cleared up by treatment, but maternal death or neonatal water intoxication may occur. Such accidents must be prevented by clinical monitoring, watching out for alarm signals (oliguria is always found, resulting from the effect of oxytocin on the kidney), minimum fluid and proportional salt intakes, careful monitoring of oxytocin infusion rates, facilitated by the use of a constant flow-rate pump.

[Posttraumatic fat embolism]

Between 1977 and 1982, fifty cases of post-traumatic fat embolism were treated in a general intensive care unit. Average age of patients was 25.5 +/- 13 years; there was no male majority. Mean free interval was 39 +/- 27 h. 12 cases (24%) had single fractures and 38 (76%) multiple fractures. Forty-four patients had a fractured femur. Thirty-two patients presented the complete clinical syndrome with general, respiratory, neurological and cutaneous signs. Thrombocytopaenia and hypocholesterolaemia were the biological signs most often seen. In forty-four patients, orthopaedic treatment consisted of immediate immobilization, usually with traction. Twenty-six patients were reoperated on: intramedullary nail for twenty patients, plate for the other six. Fat embolism appeared in spite of surgery in six cases; it worsened after surgery in six others. Seven patients had per- or postanaesthetic problems. Fourteen per cent of patients died. The decrease in mortality was mainly due to an improvement in mechanical ventilation techniques. Early surgical fixation remained the rule if there was no serious respiratory distress or haemodynamic instability, although it did not seem to change the mortality rate in this group of patients.

[Acute carbon monoxide poisoning: lung injury or cardiogenic pulmonary edema?]

The authors report 7 cases of acute pulmonary edema in acute carbon monoxide poisoning. Hemodynamic data suggest existence of a myocardial failure as a possible cause of these pulmonary edema and indicate caution for volemic expansion during the treatment of shock in carbon monoxide poisoning.

[Acute ajmaline poisoning. Study of 7 cases]

Seven cases of acute ajmaline overdose admitted over a 3 year period to a polyvalent intensive care unit are reported. The severity of this condition is related to the membrane stabilising and depolarising effects of ajmaline on the myocardium. The dose ingested varied from 10 to 40 mg/kg. The delay between ingestion and hospital admission ranged from 3 to 6 1/2 hours. The first cardiac disturbances can appear one hour after ingestion. Three cardiac arrests and one hypovolemic shock occurred. Three atrioventricular blocks, six intraventricular blocks, three ventricular tachycardias, and six prolongations of the QT interval were observed. Serum ajmaline levels varied from 0,8 to 6 mg/l. Symptomatic therapy was mainly based on sodium, temporary cardiac pacing, external DC shock, sympathomimetics and external cardiac massage with assisted ventilation. Cardiac bypass should be a part of the therapeutic arsenal. Elimination of the drug is assisted by a complete digestive evacuation. Renal or extrarenal dialysis is not indicated. One of the seven patients died. Prophylaxis is based on the non-prescription of ajmaline for benign cardiac disturbances.