A survey of tracheal intubation difficulty in the operating room: a prospective observational study.

BACKGROUND: The purpose of this study is to describe all degrees of endotracheal intubation difficulty among patients attended by eight anesthesiologists during routine surgery over a six-month period. Airway characteristics were routinely assessed preoperatively, according to the anesthesiologists' usual practice. METHODS: Difficult tracheal intubation was evaluated by the Intubation Difficulty Scale (IDS), a quantitative score based on seven variables. An IDS value of 0 is consistent with a procedure without difficulty, and an IDS > 5 with a procedure involving moderate to major difficulty. RESULTS: For 1171 patients undergoing tracheal intubation, IDS was 0 in 55%, and greater than 5 in 8% of cases. External laryngeal pressure, repositioning the patient and added use of a stylet were the most frequent methods chosen to facilitate tracheal intubation. CONCLUSION: There was a high incidence (37%) of minor difficulties encountered during routine surgery.

Early complications and value of initial clinical and paraclinical observations in victims of smoke inhalation without burns.

OBJECTIVE: To evaluate the incidence of early pulmonary complications and the value of initial clinical signs and paraclinical investigations in victims of smoke inhalation not suffering from burns following structural fires. DESIGN: Retrospective chart review. SETTING: Thirteen-bed ICU. PATIENTS: Sixty-four victims of smoke inhalation following household fires were admitted to the ICU between January 1987 and December 1992. Exclusion criteria from the study were patients with cutaneous burns or multiple trauma or blast injury, and patients found in cardiac arrest. METHODS: Clinical, biological, and radiologic parameters were collected over a 5-day period. RESULTS: The mortality rate in relation to progressive respiratory failure was 3.1%. Mean ICU stay was 5.8 days (range, 1 to 33 days), and was longer in the patients presenting with soot deposits in the oropharynx (p = 0.02), dysphonia (D) (p = 0.05), or ronchi (R) (p = 0.0004) at the first examination, and in those having a positive sputum bacteriologic analysis (p = 0.003) or requiring parenteral bronchodilator agents for more than 24 h (p = 0.04). Thirty-five patients underwent mechanical ventilation (MV) for a mean of 101.2 h (range, 8 to 648 h). Mean MV duration was higher in the patients presenting initially with R (p = 0.003), high carbon monoxide (but not cyanide) levels (p = 0.02), or a positive bacteriologic sample (p = 0.0001). Positive bacteriologic sampling correlated with the presence of D (p = 0.02) or R (p = 0.04) and with immediate intubation (p = 0.0003). No correlation was found with chest radiograph. CONCLUSIONS: In this selected series of fire victims without cutaneous burns, respiratory injury was frequent. The initial clinical signs may be helpful to predict pulmonary complications.

The intubation difficulty scale (IDS): proposal and evaluation of a new score characterizing the complexity of endotracheal intubation.

BACKGROUND: A quantitative scale of intubation difficulty would be useful for objectively comparing the complexity of endotracheal intubations. The authors have developed a quantitative score that can be used to evaluate intubating conditions and techniques with the aim of determining the relative values of predictive factors of intubation difficulty and of the techniques used to decrease such difficulties. METHODS: An Intubation Difficulty Scale (IDS) was developed, based on parameters known to be associated with difficult intubation. It was then evaluated prospectively in a group of 311 consecutive prehospital intubations and 315 intubations in an operating room. In the operating room, the IDS was compared with two other parameters: the time to completion of intubation and the visual analog scale (VAS). Time was measured by an independent observer. Operators in both groups completed a checklist regarding the conditions of intubation. RESULTS: There is a good correlation between the IDS scale and the VAS assessment of difficulty and time to completion of intubation. VAS and time to completion have a significant but lesser correlation to each other. Comparison of IDS with operator-assessed subjective categorical impression of difficulty by Kruskall-Wallis was statistically significant. CONCLUSIONS: The IDS correlates with but is less subjective than the VAS and categorical classification. IDS correlates with time to intubation, but it offers details regarding the difficulty encountered that time alone does not. This score may not only aid in evaluation of factors linked to difficult intubations, but it may provide a uniform approach to comparing studies related to this subject.

Therapeutic trial of diazepam versus placebo in acute chloroquine intoxications of moderate gravity.

OBJECTIVE: Acute chloroquine intoxication is responsible for a membrane-stabilising effect which results in electrocardiographic (ECG) and hemodynamic disturbances. Diazepam is used in acute chloroquine intoxication on the basis of clinical and experimental observations, but its utility alone, in man, remains unproven. The goal of this study was to verify whether diazepam alone has an effect on the membrane-stabilising effect observed in moderately severe chloroquine intoxications. DESIGN: Prospective, multi-center, double-blind, placebo-controlled study. SETTING: Prehospital mobile intensive care units (Paris) and hospital intensive care units (paris and Dakar). PATIENTS AND PARTICIPANTS: Adults with moderately severe intoxication defined as: a suspected ingested dose of 2 or more but less than 4 g, systolic blood pressure (SBP) higher than 80 mmHg, QRS duration less than 0.12 s and the absence of dysrhythmia at inclusion. INTERVENTIONS: Patients received either a loading dose of 0.5 mg/kg diazepam followed by an infusion of 1 mg/kg over 24 h or an equivalent volume of placebo. MEASUREMENTS AND RESULTS: Outcome was measured by serial assessments of SBP, ECG (QRS and QT segments) and clinical deterioration. There were no significant differences observed in the initial or serial ECG or SBP measurements. There were no deaths and no patient had to be removed from the study due to clinical deterioration. CONCLUSIONS: Diazepam, at the dose studied, does not appear to reverse the chloroquine-induced membrane-stabilising effect in acute moderately severe chloroquine intoxication. Supportive intensive care of these intoxications appears to be all that is necessary.

[Acute chloroquine poisoning]. / Intoxication aiguë à la chloroquine.

Acute chloroquine intoxication is responsible for grave cardiovascular disturbances which may be rapidly life-threatening. For this reason, any suspicion of acute chloroquine intoxication requires hospitalisation in an intensive care unit for a minimum of 12 hours. Cardiovascular toxicity is linked to a potent membrane-stabilizing effect, which is also responsible for transfer-dependent hypokalemia, the degree of which is directly associated with the gravity of the intoxication. Blood chloroquine concentration confirms the intoxication and is likewise closely correlated to gravity. Treatment of this intoxication, based on vascular repletion, adrenalin, assisted ventilation and diazepam has markedly improved the prognosis of these intoxications, overall mortality for all degrees of intoxication nonetheless remains to the order of 10%.

Treatment of acute chloroquine poisoning: a 5-year experience.

OBJECTIVE: To describe various aspects of prognostic and therapeutic importance in patients treated for acute chloroquine poisoning. DESIGN: Retrospective study. SETTING: Toxicology intensive care unit (ICU) of a university hospital. INTERVENTIONS: None. PATIENTS: One hundred sixty-seven consecutive patients with acute chloroquine overdose admitted to our toxicology ICU. MEASUREMENTS AND MAIN RESULTS: The mean amount ingested by history was 4.5 +2- 2.8 g. and 43 (26%) of 167 patients ingested > 5 g. The mean blood chloroquine concentration on admission was 20.5 +/- 13.4 mumol/L The majority (87%) of our patients received at least one arm of a combination therapy regimen (epinephrine, mechanical ventilation, diazepam). cardiac arrest occurred in 25 patients before hospital arrival; In seven of these patients, cardiac arrest occurred immediately after injection of thiopental. The mortality rate was 8.4% overall, and was 9.3% in patients with massive ingestions (NS vs. the group as a whole). We did not find a meaningful correlation between the amount ingested as estimated by history and the peak blood chloroquine concentration; the latter was highly correlated with the mortality rate. CONCLUSIONS: The mortality rate in patients with acute chloroquine poisoning, including those patients sick enough to be referred to a specialty unit such as ours, can be limited to < or = 10%. This finding appears to be true even in patients with massive ingestions. We were not able to correlate mortality with amount ingested by history, although the mortality rate does correlate with blood chloroquine concentration. While early use of diazepam, epinephrine, and mechanical ventilation in most of our patients may have contributed to the excellent overall results, these elements, either singly or in combination, do not appear to have a truly antidotal effect in acute chloroquine poisoning. Thiopental, on the other hand, should be used with great caution, if at all, in such cases.

Hyperthermia complicating tricyclic antidepressant overdose.

We observed a 51-year-old woman who was admitted for severe amitriptyline overdose. Besides major cardiovascular complications, the patient developed severe hyperpyrexia with a central body temperature of more than 43 degrees C for 5 h. The patient died on day 3 from cardiocirculatory collapse and arrhythmias. Hyperthermia was unresponsive to cooling with ice water, gastric lavage, muscle relaxation, and dantrolene and bromocriptine administration. The possible mechanisms of refractory hyperthermia are discussed.

A case of life-threatening lactic acidosis after smoke inhalation - interference between beta-adrenergic agents and ethanol?

A 49-year-old male developed bronchospasm and severe lactic acidosis after exposition to fire smoke. The correction of lactic acidosis following beta-adrenergic agents withdrawal, and the transitory increase in lactate after salbutamol reintroduction are consistent with hypersensitivity to salbutamol. However, the plasma lactate concentration (32.6 mmol/l) that we observed 9.5 h after admission is far above those currently seen after administration of beta-adrenergic agents. We searched for causes able to potentiate the adverse effects of these drugs and we noticed that our patient had a high plasma ethanol level (2.4 g/l). Alcohol metabolism in the liver results in generation of high NADH/NAD+ ratios, thus reducing lactate liver clearance. This observation suggests that plasma lactate levels should be monitored closely in alcoholic patients treated with beta-mimetic agents.

Hypokalaemia related to acute chloroquine ingestion.

Large doses of chloroquine can cause poisoning. Our aim was to determine the possible relation between the plasma potassium concentration on admission with the severity of acute chloroquine poisoning and to assess the mechanism of chloroquine-induced hypokalaemia. We conducted a retrospective study of 191 consecutive cases. The main data included the occurrence of vomiting before admission, plasma, and urinary potassium concentration at admission, whole blood chloroquine concentration on admission, haemodynamic parameters and ECG, administration of catecholamines and outcome. Mean blood chloroquine level was 20.1 mumol/L (SD 14.3) (therapeutic level < or = 6 mumol/L). Mean plasma potassium concentration was 3.0 mmol/L (0.8) and was lower in the subjects who died than in those who survived (p = 0.0003). Plasma potassium varied directly with the systolic blood pressure and inversely with the QRS and QT. Plasma potassium varied inversely with the blood chloroquine (p = 0.0001; tau = -0.42). Acute chloroquine intoxication is responsible for a hypokalaemia which correlates with the gravity of the intoxication and may be due to a transport-dependent mechanism. Plasma potassium concentrations should be carefully observed, particularly among patients who also receive catecholamine infusions. We should keep in mind, however, that overzealous repletion invokes the risk of subsequent hyperkalaemia and thus should be avoided.