Automatic oxygen administration and weaning in patients following mechanical ventilation.

PURPOSE: To evaluate efficacy of FreeO2 device in oxygen weaning of patients after being liberated from mechanical ventilation (MV). METHODS: Prospective crossover cohort study in patients admitted to ICU and after MV weaning. FreeO2 curves were recorded during constant flow and FreeO2 modes. Oxygenation parameters and O2 consumption were assessed. RESULTS: Fifty one records were obtained in 51 patients (median age, 62 years, 54.9% had COPD, admission for acute respiratory failure in 96%). NIV was used initially in 68.6%. For a median records duration of 2.04 h, the time spent within target SpO2 range was significantly higher with FreeO2 mode compared to constant O2 flow mode [86.92% (77.11-92.39) vs 43.17% (5.08-75.37); p < 0.001]. Time with hyperoxia was lower with FreeO2 mode: 8.68% (2.96-15.59) vs 38.28% (2.02-86.34). Times with hypoxaemia, and with severe desaturation, were similar. At the end of FreeO2 mode, O2 flow was lower than 1 l/min in 28 patients (54.9%), with a median of 0.99 l/min. CONCLUSIONS: For the purpose of oxygen weaning in patients recovering from MV, automatic O2 titration with FreeO2 was associated with a substantial reduction in O2 delivery and better oxygenation parameters in comparison with constant O2 flow.

Impact of the humidification device on intubation rate during noninvasive ventilation with ICU ventilators: results of a multicenter randomized controlled trial.

PURPOSE: The use of heat and moisture exchangers (HME) during noninvasive ventilation (NIV) can increase the work of breathing, decrease alveolar ventilation, and deliver less humidity in comparison with heated humidifiers (HH). We tested the hypothesis that the use of HH during NIV with ICU ventilators for patients with acute respiratory failure would decrease the rate of intubation (primary endpoint) as compared with HME. METHODS: We conducted a multicenter randomized controlled study in 15 centers. After stratification by center and type of respiratory failure (hypoxemic or hypercapnic), eligible patients were randomized to receive NIV with HH or HME. RESULTS: Of the 247 patients included, 128 patients were allocated to the HME group and 119 to the HH group. Patients were comparable at baseline. The intubation rate was not significantly different: 29.7% in the HME group and 36.9% in the HH group (p = 0.28). PaCO2 did not significantly differ between the two arms, even in the subgroup of hypercapnic patients. No significant difference was observed for NIV duration, ICU and hospital LOS, or ICU mortality (HME 14.1 vs. HH 21.5%, p = 0.18). CONCLUSIONS: In this study, the short-term physiological benefits of HH in comparison with HME during NIV with ICU ventilators were not observed, and no difference in intubation rate was found. The physiologic effects may have been obscured by leaks or other important factors in the clinical settings. This study does not support the recent recommendation favoring the use of HH during NIV with ICU ventilators.

Influence of body mass index on outcome of the mechanically ventilated patients.

BACKGROUND: There are limited data on the impact of body mass index on outcomes in mechanically ventilated patients. METHODS: Secondary analysis of a cohort including 4698 patients mechanically ventilated. Patients were screened daily for management of mechanical ventilation, complications (acute respiratory distress syndrome, sepsis, ventilator associated pneumonia, barotrauma), organ failure (cardiovascular, respiratory, renal, hepatic, haematological) and mortality in the intensive care unit. To estimate the impact of body mass index on acute respiratory distress syndrome and mortality, the authors constructed models using generalised estimating equations (GEE). RESULTS: Patients were evaluated based on their body mass index: 184 patients (3.7%) were underweight, 1995 patients (40%) normal weight, 1781 patients (35.8%) overweight, 792 patients (15.9%) obese and 216 patients (4.3%) severely obese. Severely obese patients were more likely to receive low tidal volume based on actual body weight but high volumes based on predicted body weight. In obese patients, the authors observed a higher incidence of acute respiratory distress syndrome and acute renal failure. After adjustment, the body mass index was significantly associated with the development of acute respiratory distress syndrome: compared with normal weight; OR 1.69 (95% CI 1.07 to 2.69) for obese and OR 2.38 (95% CI 1.15 to 4.89) for severely obese. There were no differences in outcomes (duration of mechanical ventilation, length of stay and mortality in intensive care unit and hospital) based on body mass index categories. CONCLUSIONS: In this cohort, obese patients were more likely to have significant complications but there were no associations with increased mortality.

[Multiple cranial nerve involvement: consider the diagnosis of cephalic tetanus. A case report and review of the literature]. / Atteinte multiple des nerfs crâniens : atteinte multiple des nerfs crâniens au cours du tétanos céphalique. À propos d'une observation et revue de la littérature.

INTRODUCTION: Cephalic tetanus is the most serious form of localized tetanus. It associates trismus with impairment of one or more cranial nerves. It was a rare condition, whose diagnosis can raise several problems. CASE REPORT: A 49-year-old-man presented multiple and unilateral cranial nerve involvement revealing cephalic tetanus. CONCLUSION: This case illustrates the importance of considering cephalic tetanus when patients present cranial nerve palsy associated with injury.

Short-term treatment of severe hypertension of pregnancy: prospective comparison of nicardipine and labetalol.

OBJECTIVES: To assess the efficacy and safety of nicardipine in comparison to labetalol in the initial management of severe hypertension in pregnancy. DESIGN. Randomized prospective study. SETTING: The obstetric ward of the teaching hospital of Monastir Tunisia. PATIENTS: Sixty consecutive pregnant women admitted beyond the 24th week of pregnancy with severe hypertension. INTERVENTION: Patients were randomly assigned to receive intravenously for 1 h either labetalol ( n=30) or nicardipine ( n=30). Treatment was titrated to achieve a 20% lowering of blood pressure (BP). MEASUREMENTS: Maternal BP and heart rate were measured at inclusion and repeatedly during the first hour following the drugs administration. Fetal heart rate was recorded throughout the study period. The main outcome endpoints were the success rate and the length of time needed to achieve the therapeutic goal. The rate of maternal and fetal adverse events and dose adjustments were also analyzed. RESULTS: Labetalol and nicardipine achieved the 20% lowering in BP in the same proportion (63% and 70% success rates, respectively). Overall nicardipine caused a significantly greater decrease in systolic and diastolic BP. No patient had any episode of hypotension. The length of time to achieve the BP goal was also similar (12 vs. 11 min, respectively). Both drugs were well tolerated except for a moderate tachycardia observed with the use of nicardipine. CONCLUSION: Nicardipine and labetalol are effective and safe in the initial treatment of severe hypertension of pregnancy.

Once daily oral ofloxacin in chronic obstructive pulmonary disease exacerbation requiring mechanical ventilation: a randomised placebo-controlled trial.

BACKGROUND: The role of antibiotics in treatment of patients with moderate exacerbations of chronic obstructive pulmonary disease (COPD) is uncertain, but such treatment might be useful in very severe episodes. Our objective was to assess the effects of ofloxacin in patients with exacerbations of COPD who required mechanical ventilation. METHODS: We did a prospective, randomised, double-blind, placebo-controlled trial in 93 patients with acute exacerbation of COPD who required mechanical ventilation. Patients were randomly assigned to receive oral ofloxacin 400 mg once daily (n=47) or placebo (46) for 10 days. Primary endpoints were death in hospital and need for an additional course of antibiotics, both separately and in combination. Analysis was by intention to treat. FINDINGS: Three patients dropped out of the study. Two (4%) patients receiving ofloxacin died in hospital and ten (22%) did so in the placebo group (absolute risk reduction 17.5%, 95% CI 4.3-30.7, p=0.01). Treatment with ofloxacin significantly reduced the need for additional courses of antibiotics (28.4%, 12.9-43.9, p=0.0006). The combined frequency of death in hospital and need for additional antibiotics was significantly lower in patients assigned to ofloxacin than in those receiving placebo (45.9%, 29.1-62.7, p<0.0001). The duration of mechanical ventilation and hospital stay was significantly shorter in the ofloxacin group than in the placebo group (absolute difference 4.2 days, 95% CI 2.5-5.9; and 9.6 days, 3.4-12.8, respectively). INTERPRETATION: New fluoroquinolones, such as ofloxacin, are beneficial in the treatment of COPD exacerbation requiring mechanical ventilation.

Treatment of acute hypoxemic nonhypercapnic respiratory insufficiency with continuous positive airway pressure delivered by a face mask: A randomized controlled trial.

CONTEXT: Continuous positive airway pressure (CPAP) is widely used in the belief that it may reduce the need for intubation and mechanical ventilation in patients with acute hypoxemic respiratory insufficiency. OBJECTIVE: To compare the physiologic effects and the clinical efficacy of CPAP vs standard oxygen therapy in patients with acute hypoxemic, nonhypercapnic respiratory insufficiency. DESIGN, SETTING, AND PATIENTS: Randomized, concealed, and unblinded trial of 123 consecutive adult patients who were admitted to 6 intensive care units between September 1997 and January 1999 with a PaO(2)/FIO(2) ratio of 300 mm Hg or less due to bilateral pulmonary edema (n = 102 with acute lung injury and n = 21 with cardiac disease). INTERVENTIONS: Patients were randomly assigned to receive oxygen therapy alone (n = 61) or oxygen therapy plus CPAP (n = 62). MAIN OUTCOME MEASURES: Improvement in PaO(2)/FIO(2) ratio, rate of endotracheal intubation at any time during the study, adverse events, length of hospital stay, mortality, and duration of ventilatory assistance, compared between the CPAP and standard treatment groups. RESULTS: Among the CPAP vs standard therapy groups, respectively, causes of respiratory failure (pneumonia, 54% and 55%), presence of cardiac disease (33% and 35%), severity at admission, and hypoxemia (median [5th-95th percentile] PaO(2)/FIO(2) ratio, 140 [59-288] mm Hg vs 148 [62-283] mm Hg; P =.43) were similarly distributed. After 1 hour of treatment, subjective responses to treatment (P<.001) and median (5th-95th percentile) PaO(2)/FIO(2) ratios were greater with CPAP (203 [45-431] mm Hg vs 151 [73-482] mm Hg; P =.02). No further difference in respiratory indices was observed between the groups. Treatment with CPAP failed to reduce the endotracheal intubation rate (21 [34%] vs 24 [39%] in the standard therapy group; P =.53), hospital mortality (19 [31%] vs 18 [30%]; P =.89), or median (5th-95th percentile) intensive care unit length of stay (6.5 [1-57] days vs 6.0 [1-36] days; P =.43). A higher number of adverse events occurred with CPAP treatment (18 vs 6; P =.01). CONCLUSION: In this study, despite early physiologic improvement, CPAP neither reduced the need for intubation nor improved outcomes in patients with acute hypoxemic, nonhypercapnic respiratory insufficiency primarily due to acute lung injury. JAMA. 2000;284:2352-2360.

Continuous versus intermittent nebulization of salbutamol in acute severe asthma: a randomized, controlled trial.

STUDY OBJECTIVE: This study was conducted to compare the clinical and spirometric effects of continuous and intermittent nebulization of salbutamol in acute severe asthma. METHODS: Forty-two consecutive patients presenting to the emergency department for acute severe asthma (peak expiratory flow [PEF] mean+/-SD, 24%+/-12% predicted) were prospectively randomly assigned to receive 27.5 mg of salbutamol by either continuous or intermittent nebulization over a 6-hour period. The continuous nebulization group received 15 mg of salbutamol during the first hour and 12.5 mg over the next 5 hours. The intermittent nebulization group received 5 mg of salbutamol every 20 minutes during the first hour and 2.5 mg hourly over the next 5 hours. All participants received oxygen and intravenous hydrocortisone. Clinical and spirometric assessment was performed at baseline, 40 minutes, 60 minutes, and at 3 and 6 hours after the start of the nebulization. Secondary endpoints were the respective rates of hospitalization and treatment failure. RESULTS: A significant clinical and spirometric improvement was observed in both groups over baseline as soon as the 40th minute and was sustained thereafter (absolute PEF increase at the sixth hour 30%+/-18% and 32%+/-22% in the continuous and intermittent nebulization groups, respectively; P <.01 over baseline). PEF and the clinical score evolved similarly in both groups. There was no difference between the groups regarding the failure rate of the initial bronchodilator treatment to terminate the asthma attack (3 [14%] in the continuous nebulization group and 2 [9.5%] in the intermittent nebulization group, absolute difference 4.5% [95% confidence interval -14% to 23%]). Eight (38%) patients and 9 (43%) patients from the continuous and intermittent nebulization groups, respectively, required hospitalization according to predefined criteria (absolute difference 4.8% [95% confidence interval -24% to 34%]). CONCLUSION: We did not observe an appreciable difference between continuous and intermittent nebulization of salbutamol in acute severe asthma. The decision to use one of these nebulization methods should be based on logistical considerations.

Serotherapy in scorpion envenomation: a randomised controlled trial.

BACKGROUND: Evidence for the benefit of scorpion antivenom, the only specific treatment for scorpion envenomation, is scarce, despite its common use. We did a prospective, randomised, controlled trial to assess the efficacy of routine administration of scorpion antivenom to scorpion-stung patients, irrespective of clinical severity. METHODS: We included 825 consecutive patients older than 10 years, who presented to the accident and emergency department of the hospital in Tozeur, Tunisia. We graded severity by absence (grade I) or presence (grade II) of systemic manifestations of scorpion envenomation. Patients were randomly assigned placebo (n=413) or 20 mL bivalent intraveneous scorpion antivenom (n=412). All patients were observed for 4 h. Patients who developed life-threatening symptoms were admitted to the intensive-care unit. At the end of 4 h observation we reassessed grade and discharged grade II patients and admitted grade II patients. We assessed the preventive and curative effects of scorpion antivenom by prevention of worsening grade or by improvement from grade II to grade I. FINDINGS: Distribution of severity grades was similar in the two groups at baseline, as were the cure rates (55% scorpion antivenom, 66% placebo, absolute difference, 11% [95% CI -4.8 to 26.8]; p=0.234). Preventive effects were seen in 94% and 96% of patients in the scorpion antivenom and placebo groups, respectively, who were initially grade I and who remained symptom-free (absolute difference, 2% [-1.27 to 5.27]; p=0.377). Time from scorpion sting to administration of scorpion antivenom did not affect curative and preventive effects. INTERPRETATION: We found no benefit in routine administration of scorpion antivenom after scorpion sting, irrespective of clinical severity. Future studies should focus on patients with the most severe symptoms and signs.

Dobutamine in severe scorpion envenomation: effects on standard hemodynamics, right ventricular performance, and tissue oxygenation.

OBJECTIVES: To document the effects of dobutamine on standard hemodynamics and right ventricular (RV) performance in patients exhibiting pulmonary edema following severe scorpion envenomation, and to characterize the tissue oxygenation profile in patients sustaining scorpion envenomation-related shock. DESIGN: Prospective cohort study. SETTING: An ICU in a university hospital. PATIENTS: Nineteen consecutive patients were admitted to the ICU for severe scorpion envenomation; all 19 patients exhibited hemodynamic pulmonary edema, and 10 patients had peripheral shock. INTERVENTIONS: All patients underwent a hemodynamic study with a Swan-Ganz catheter. In 8 of 19 patients, the thermodilution catheter was equipped with a fast-response thermistor. MEASUREMENTS AND RESULTS: Standard hemodynamic parameters were recorded on admission and following the infusion of dobutamine in all patients at a dosage, from 7 to 20 microg/kg/min, intended to achieve the best hemodynamic and tissue oxygenation compromise. RV ejection fraction (RVEF) and RV volumes were simultaneously recorded in 8 patients, and tissue oxygenation parameters were assessed in the 10 patients with peripheral shock. The clinical signs of tissue hypoperfusion improved, and optimal hemodynamic parameters were achieved at a mean +/- SD dobutamine dosage of 17 +/- 7 microg/kg/min. Dobutamine infusion evoked statistically significant increases in cardiac index, from 2.3 +/- 0.6 to 3.6 +/- 0.7 L/min/m2; stroke volume index, from 18 +/- 5 to 31 +/- 10 mL/m2; and systemic arterial pressure, from 64 +/- 12 to 78 +/- 14 mm Hg. Pulmonary artery occlusion pressure (PAOP) and venous admixture decreased significantly: from 23 +/- 4 to 15 +/- 6 mm Hg and from 29 +/- 7% to 20 +/- 5%, respectively. With respect to RV function, dobutamine infusion significantly increased the RVEF, from 24 +/- 7% to 42 +/- 9%, without significantly changing the RV end-diastolic volume index, reflecting an enhanced RV contractility. In patients with peripheral circulatory failure, the baseline tissue oxygenation profile was consistent with cardiogenic shock, showing increased oxygen extraction as a consequence of a striking depression in oxygen delivery (DO2). After dobutamine infusion, DO2 improved significantly, from 386 +/- 104 to 676 +/- 156 mL/min/m2, with a significant decrease in oxygen extraction, from 34 +/- 8% to 24 +/- 6%. CONCLUSIONS: In severe scorpion envenomation, dobutamine infusion improves impaired heart function. The effects involve both left ventricular and RV dysfunction. Impaired tissue oxygenation is also improved.

Efficacy of serotherapy in scorpion sting: a matched-pair study.

BACKGROUND/OBJECTIVE: Although evidence of scorpion antivenin effectiveness in the clinical setting is lacking, scorpion antivenin is generally considered the only specific treatment for scorpion sting irrespective of its clinical severity. We conducted a matched-pair study to assess the efficacy of systematic administration of scorpion antivenin. METHODS: Among 600 stung patients who participated in a study on the efficacy of high-dose hydrocortisone after scorpion sting, 135 (cases) had been treated with 10 to 20 mL intravenous scorpion antivenin (neutralizing 10 LD50 venom/mL). Controls were matched on disease severity on arrival to the emergency department. The severity of envenomation was graded I or II according to the absence (grade I) or the presence (grade II) of systemic manifestations of scorpion envenomation. Assessment of scorpion antivenin efficacy was based on the rate of changing severity grade in both groups (clinical improvement or worsening during an observation period of at least 4 hours). RESULTS: Both groups were similar with respect to clinical severity (36 patients were graded II in each group), age, sex, time-lapse between scorpion sting and ED arrival, and the administration of adjunctive therapy such as hydrocortisone. By the 4-hour evaluation, 50% and 64% of patients initially graded II exhibited a substantial clinical improvement in cases and controls, respectively, suggesting similar effects in cases and controls. There was no difference in preventive effects: 13% and 10% of cases and controls developed systemic manifestations of scorpion envenomation during the 4-hour observation period; 23% of cases and 17% controls were hospitalized by this time. There was no difference in the duration of hospitalization. Three cases developed anaphylactic shock as a consequence of scorpion antivenin administration, while 1 scorpion antivenin-untreated patient died from refractory shock. CONCLUSION: Systematic administration of scorpion antivenin irrespective of clinical severity did not alter the clinical course of scorpion sting. A prospective study is needed concerning the response of the more severe scorpion envenomations.

Development of an ELISA for the detection of scorpion venoms in sera of humans envenomed by Androctonus australis garzonii (Aag) and Buthus occitanus tunetanus (Bot): correlation with clinical severity of envenoming in Tunisia.

A sandwich ELISA was set up for measuring scorpion venom levels in sera of accidentally envenomed humans with the aim to establish a quantitative relationship between these levels, envenoming severity and clinical symptoms. This assay used equine polyclonal F(ab')2, specific to two North African scorpion (Androctonus australis garzonii: Aag and Buthus occitanus tunetanus: Bot) venoms. The test proved to be simple, reproducible, very sensitive (detection limit = 0.9 ng/ml) and linear between 0.5 and 15 ng/ml of venom concentrations. A large survey on scorpion sting envenomings was conducted from 1993 to 1996 in Tunisia to gather accurate epidemiological, clinical and biological data from victims as well as informations on the treatment that they had received. Victims were classified into three grades (GI, GII and GIII) of increasing severity according to clinical signs of envenoming. Blood samples were collected from victims and tested by ELISA for their content of Aag and Bot venoms. A strong correlation was found between clinical symptoms of envenoming and the level of scorpion venom antigens in serum (r = 0.980). Mean serum venom concentrations were: 2.65 +/- 0.81 ng/ml in GI envenoming, 9.79 +/- 4.08 ng/ml in GII and 21.7 +/- 6.51 ng/ml in GIII. The difference between each group was statistically significant (p < 0.01). This ELISA may prove to be helpful to establish a rationale approach of specific antivenom therapy.

Predictive value of severity scoring systems: comparison of four models in Tunisian adult intensive care units.

OBJECTIVES: To compare the performance of four severity scoring systems: the Acute Physiology and Chronic Health Evaluation (APACHE) II, the new versions of the Mortality Prediction Model (MPM0 and MPM24), and the Simplified Acute Physiology Score (SAPS) II. DESIGN: A prospective cohort study. SETTING: Three Tunisian intensive care units (ICUs). PATIENTS: Consecutive, unselected adult patients (n = 1325). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Overall, observed death rates were higher than predicted by all models except MPM0. All the evaluated scoring systems had good discrimination power as expressed by area under the receiver operating characteristics curve, but their calibration was less perfect when compared with original validation reports. There were no major differences between the models with regard either to discrimination or calibration performance. CONCLUSION: Despite an overall good discrimination, APACHE II, MPM0, MPM24, and SAPS II showed a less satisfactory calibration in our Tunisian sample of ICU patients. Part of the models inaccuracy could be related to quality of care problems in our ICUs, but this issue needs further analysis.

Intensive care use in a developing country: a comparison between a Tunisian and a French unit.

OBJECTIVES: To compare the variations in intensive care (ICU) outcome in relation to variations in resources utilization and costs between a developed and a developing country with different medical and economical conditions. DESIGN AND SETTING: Prospective comparison between a 26-bed French ICU and an 8-bed Tunisian ICU, both in university hospitals. PATIENTS: Four hundred thirty and 534 consecutive admissions, respectively, in the French and Tunisian ICUs. MEASUREMENTS: We prospectively recorded demographic, physiologic, and treatment information for all patients, and collected data on the two ICU structures and facilities. Costs and ICU outcome were compared in the overall population, in three groups of severity indexes and among selected diagnostic groups. RESULTS: Tunisian patients were significantly younger, were in better health previously and were less severely ill at ICU admission (p < 0.01). French patients had a lower overall mortality rate (17.2 vs 22.5%; p < 0.01) and received more treatment (p < 0.01). In the low severity range, the outcome and costs were similar in the two countries. In the highest severity range, Tunisian and French patients had similar mortality rates, while the former received less therapy throughout their ICU stays (p < 0.05). Conversely, in the mid-range of severity, mortality was higher among Tunisian patients, and a difference in management was identified in COPD patients. CONCLUSION: Although the Tunisian ICU might appear more cost-effective than the French one in the highest severity group of patients, most of this difference appeared in relation to shorter lengths of ICU stay, and a poorer efficiency and cost-effectiveness was suggested in the mid-range severity group. Differences in economical constraints may partly explain differences in ICU performances. These results indicate where resource allocation could be directed to improve the efficiency of ICU care.

Successful weaning from mechanical ventilation following balloon mitral commissurotomy.

Successful weaning from mechanical ventilation (MV) following percutaneous balloon mitral commissurotomy (BMC) is reported in a 59-year-old woman with severe symptomatic rheumatic mitral stenosis. The patient was admitted to the Intensive Care Unit for acute respiratory failure secondary to pulmonary edema requiring intubation and mechanical ventilation. After resolution of the acute phase, she became completely dependent on mechanical ventilatory support. In spite of the reinforcement of conventional therapy (diuretics, digitalis, vasodilators), weaning attempts were unsuccessful because of persisting elevated left atrial pressure. Percutaneous BMC was performed with favorable hemodynamic results, allowing the removal of external ventilatory support 24 h later and discharge from the Intensive Care Unit the same day.