[Field 5. Safety practices procedures for mechanical ventilation. French-speaking Society of Intensive Care. French Society of Anesthesia and Resuscitation]

Invasive or endotracheal mechanical ventilation can lead to numerous complications likely to burden morbidity and mortality of patients in the intensive care unit. Various safety practices for mechanical ventilation may involve intubation, the mechanical ventilation period, weaning and extubation, the use of tracheostomy as well as non-invasive ventilation. The main objective of safety practices described in this chapter is to prevent or avoid the main risks due to invasive mechanical ventilation.

[Assessment of quality of life for home ventilated patients with Duchenne muscular dystrophy]

A social and psychological survey was conducted for patients with DMD submitted to home mechanical ventilation for more than one year. Thirty six were tracheostomized and 16 were using non invasive ventilation. Fifty two patients were recruited: 36 were tracheostomized and 16 were using non invasive ventilation. Mean age was 25 +/- 5 years. In the two groups: 1- the main disagreement was air leaking and cutaneous erosions. 2- when present, headache, dyspnea, sleep troubles and general fatigue were improved by mechanical ventilation. 3- ventilation was considered as improving health but with an increasing of dependencies. 4- Majors disappointment are sexual life (70 percent) and physical status (40 percent) but patients spent more than half time with positive feeling (92 percent). There was no difference between satisfaction evaluation and type of ventilation. Home ventilated patients with DMD have positive assessment of satisfaction. Despite technical disagreement as air leaking, patients feel an improvement of their life and advise other DMD to use early home ventilation.

Critical incidents related to invasive mechanical ventilation in the ICU: preliminary descriptive study

OBJECTIVES

To establish a preliminary list of critical incidents (CIs) associated with mechanical ventilation and to describe a CI reporting method.

DESIGN

A list of CIs was established based on a consensus among ICU caregivers. The list was compared to CIs collected prospectively during a predefined study period.

SETTING

The clinical observations were conducted in two intensive care units.

PATIENTS

All patients receiving mechanical ventilation were included.

MEASUREMENTS AND RESULTS

The list of CIs included death and 62 other CI types categorized as immediately life-threatening, secondarily life-threatening, or non-life-threatening. The observational study identified 527 CIs in 137 patients. Virtually all non-life-threatening CIs were ascribed to failure to comply with safety rules or to equipment failure and 40% of life-threatening CIs to the course of the disease or to patient-related factors. The match between CI types on the list and CI types observed in the ICUs was excellent.

CONCLUSIONS

Use of our reporting method to create a CI database in a multicenter study including ICUs with varying recruitment patterns may help to identify markers suitable for routine continuous use as part of a quality-assurance program.

Noninvasive ventilation reduces mortality in acute respiratory failure following lung resection

When treated with invasive endotracheal mechanical ventilation (ETMV), acute respiratory insufficiency after lung resection is fatal in up to 80% of cases. Noninvasive positive-pressure ventilation (NPPV) may reduce the need for ETMV, thereby improving survival. We conducted a randomized prospective trial to compare standard therapy with and without nasal-mask NPPV in patients with acute hypoxemic respiratory insufficiency after lung resection. The primary outcome variable was the need for ETMV and the secondary outcome variables were in-hospital and 120-d mortality rates, duration of stay in the intensive care unit, and duration of in-hospital stay. Twelve of the 24 patients (50%) randomly assigned to the no-NPPV group required ETMV, versus only five of the 24 patients (20.8%) in the NPPV group (p = 0.035). Nine patients in the no-NPPV group died (37.5%), and three (12.5 %) patients in the NPPV group died (p = 0.045). The other secondary outcomes were similar in the two groups. NPPV is safe and effective in reducing the need for ETMV and improving survival after lung resection.

[Corticotherapy in severe infectious states]

Septic shock is one of the leading cause of death in modern countries. Scientists have made huge improvement in the understanding of mechanisms of inflammation, and the sequence of activation of the various pro and anti-inflammatory markers is now well known. By contrary, physicians have failed to improve survival from septic shock, in spite of the development of specific targets of the various points of the cytokine cascade sought to have a key role in host survival to sepsis. Corticosteroids were among the first anti-inflammatory drugs, which have been tested in high quality randomised controlled trials. These trials clearly showed that patients with septic shock are unlikely to benefit from a short course of a large dose of an anti-inflammatory steroid. More recent findings highlighting the role of the integrity of the hypothalamic-pituitary -adrenal axis to appropriately respond to a septic insult, have led to a reappraisal of the use of steroids in septic shock. Several high quality randomised controlled trials have evaluated the efficacy and safety of a prolonged treatment with low dose hydrocortisone in severe sepsis. These trials strongly suggested that this strategy of corticotherapy reduced the morbidity of septic shock and may favourably affect survival from septic shock.

Postural breathing pattern changes in patients with myotonic dystrophy

We recorded by pneumotachography the breathing in nine patients with myotonic dystrophy (MD), both seated and supine and with eyes open in both positions. Irregular breathing (coefficient of variation >20% for VT and TTOT) was observed in six of the patients, two of whom showed irregularity in both positions whilst the remaining four had irregular breathing only when supine. In addition, in this latter group, irregularities first appeared in VT and only after a few minutes in TTOT. Whereas in the group exhibiting irregular breathing in both seated and supine positions, irregularities were observed throughout the recording. However, no significant difference in any ventilatory variable was observed as between the two postures. Rib cage (RC) and abdomen (AB) motions were recorded by uncalibrated respiratory inductance plethysmography. Although for MD patients the mean values of the RC/AB ratio lay within the normal range the relative decrease in value as between seated (0.78+/-0.52) and supine (0.31+/-0.13) position was less than in healthy subjects. These observations suggest that MD may cause deficiencies in several mechanisms. Analyses of the respiratory pattern in each patient may provide information leading to the identification of the impaired respiratory mechanisms.

Association of herpes simplex virus encephalitis and paraneoplastic encephalitis - a clinico-pathological study

A 57 year-old woman developed acute limbic encephalitis and brainstem dysfunction. Anti-HU antibodies were repeatedly detected in serum and CSF. Postmortem examination showed necrotic and hemorrhagic lesions in the temporal lobes characteristic of herpes simplex virus encephalitis, which was confirmed by immunocytochemistry, and Purkinje cell loss with proliferation of Bergman glia and myelin loss in the external aspect of the dentate nuclei characteristic of paraneoplastic encephalitis. PCR-assay performed on temporal tissue extracts was positive for HSV-1. There was no identifiable neoplasm. This unusual association raises the possibility of a link between the two diseases.

Treatment of the adult Guillain-Barré syndrome: indications for plasma exchange

The Guillain-Barré syndrome is the most common cause of acute flaccid paralysis. Currently, 5% of patients die and 10% are left with severe motor sequelae at one year. Multidisciplinary teams, trained to specific treatments, are required to manage these patients. Oral and intravenous steroid treatment of GBS has been disappointing. Two large randomized clinical trials comparing plasma exchange (PE) to standard supportive treatment have shown a short-term and a one-year benefit of PE. Appropriate number of exchanges and indications of PE are now more precisely known. Patients with mild forms of the disease (able to walk) should receive two PEs, while a further two exchanges should be done in case of deterioration or in advanced forms (loss of walking ability, mechanical ventilation). A greater number of exchanges does not appeared beneficial. More recently, two randomized trials produced some evidence that intravenous immune globulin (IVIg, 0.4 g/kg daily for five days) and PE had equivalent efficiency in advanced forms. The combination of PE with IVIg did not yield a significant advantage, but did increase cost and risk. In advanced forms, the choice between PE and IVIg depends on the contraindications of each treatment.

[Long-term ventilation at home in adults with neurological diseases]

Respiratory handicap due to neurological diseases is often underestimated. Given clinical signs are either mild or absent, systematic measurement of the vital capacity is the best mean to detect in practice the restrictive syndrome. The onset of home mechanical ventilatory support should be decided at steady state, apart from episodes of acute respiratory failure. Two types of indications should be distinguished. Necessary ventilation aims at supplying over day and night the respiratory insufficiency incurred by the paralysis of respiratory muscles. Although the criteria for the use of such a supply differ according to the neurological disease, a daytime hypercapnia above 45 mmHg is widely accepted in the literature. It is otherwise established to use first a non invasive technique, while tracheostomy is secondarily proposed in case of failure of these techniques. The application of this therapeutic strategy in Duchenne de Boulogne muscular dystrophy showed that, given that tracheostomy will become necessary in this evolutive disease, proposal of an early tracheostomy is not nonsensical. By contrast, preventive ventilation aims at preventing from the aggravation of the restrictive syndrome in those patients with no criterion for necessary ventilation. It has been proved ineffective in Duchenne muscular dystrophy through a controlled clinical trial.

Simplified acute physiology score II for measuring severity of illness in intermediate care units

OBJECTIVES

To assess the efficacy of the Simplified Acute Physiology Score (SAPS II) in intermediate care units. A number of patients hospitalized in the intensive care unit (ICU) could be hospitalized in alternative structures, intermediate care units, which are equipped to handle their monitoring needs and able to provide adequate treatment at a lower cost. Characterization of the patients relies on the assessment of their severity of illness by severity scores. The efficiency of severity scores has been established in ICU patients, but not in the setting of intermediate care units.

DESIGN

Prospective study.

SETTING

Intermediate care unit of a multidisciplinary hospital.

PATIENTS

Four hundred thirty-three patients admitted to the intermediate care unit.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 561 consecutive patients admitted to the intermediate care unit during a 12-mo period, 433 patients could be included in the analysis. Patients were admitted from the emergency ward (60.9%). Of the study patients, 60.9% were admitted from the emergency ward for mostly (96%) medical reasons. Average length of stay was 3.1 +/- 2.3 (SD) days. Death rate in the intermediate care unit was 2.7% (n = 11). Average SAPS II was 22.3 +/- 12.0 (range 6 to 73). Hospital death rate was 8.1%, whereas the expected mortality rate derived from SAPS II was 8.7%. To assess the performance of the system, a formal goodness-of-fit test was performed to evaluate calibration. Calibration was accurate using the C coefficient of Hosmer-Lemeshow statistics (C = 2.4; p> 0.5). The discriminant power of SAPS II, measured by the area under the receiver operating characteristic curve was excellent (0.85 +/- 0.04).

CONCLUSIONS

The SAPS II assessment of severity of illness in patients admitted to an intermediate care unit is reliable. These results will need to be confirmed, using different patient samplings from intermediate care units.

[Treatment of Guillain-Barré syndrome in adults: role of plasma exchange]

PURPOSE

To review recent data on treatment of Guillain-Barré syndrome, especially indications of plasma exchange.

DATA SYNTHESIS

Guillain-Barré syndrome is the most common cause of acute flaccid paralysis. The current mortality is 5%, sever motor sequelae persist after 1 year in 10% of cases. Multidisciplinary teams are required to treat these patients, trained to all specific treatments. Oral and intravenous steroids have proven ineffective. Two large randomized clinical trials comparing plasma exchange (PE) with no treatment have shown a short-term and a 1-year benefit. Appropriate number of exchanges and indications are now more precisely known. In mild form (walking possible), patients should receive two PEs. A further two exchanges should be done in case of deterioration or in advanced forms (loss of walking ability, mechanical ventilation). More exchanges are not beneficial. Recently two new randomized trials have produced evidence that intravenous immune globulin (IVIg) (0.4 g/kg/d for 5 days) were as effective as five PEs in advanced forms. The combination of PE with IVIg did not confer a significant advantage, while increasing cost and risks.

CONCLUSION

The combination of PE with IVIg did not confer, in advanced forms, the choice between PE and IVIg depends of the contra-indications of each treatment.

Influence of the severity of illness measured by the Simplified Acute Physiology Score (SAPS) on occurrence of nosocomial infections in ICU patients

To evaluate the ability of the Simplified Acute Physiology Score (SAPS) to predict the occurrence of hospital-acquired infections in intensive care unit (ICU) patients, we conducted a cohort study in an eight-bed combined ICU. From January 1991 to December 1992, 690 patients were admitted in the ICU and 656 stayed at least 48 h. Patients' severity of illness was estimated within the first 24 h of the ICU stay using the SAPS. Nosocomial infection rates were compared between the high SAPS group (> 10 points) and the low SAPS group (< or = 10 points), with the cut-off point chosen according to a ROC curve. One hundred (15.2%) patients developed hospital-acquired infections during their ICU stay. The mean SAPS of infected patients was significantly higher than the mean SAPS of noninfected patients (15.4 +/- 4.3 vs. 12.0 +/- 5.9 points, P < 0.0001). Significantly more infections occurred in the patients with a SAPS > 10 points (20.9% vs. 5.1%, P < 0.0001). Sensitivity, specificity, positive and negative predictive values for a SAPS > 10 points were 88, 40, 21, and 95%, respectively. Our results suggest that 95% of patients at low risk for developing hospital-acquired infections could be identified on admission with the use of severity scoring systems such as SAPS < or = 10 points.