Nocturnal mechanical ventilation for chronic hypoventilation in patients with neuromuscular and chest wall disorders

BACKGROUND

Chronic alveolar hypoventilation is a common complication of many neuromuscular and chest wall disorders. Long-term nocturnal mechanical ventilation is increasingly used to treat it.

OBJECTIVES

To examine the efficacy of nocturnal mechanical ventilation in relieving hypoventilation related symptoms and in prolonging survival in people with neuromuscular or chest wall disorders.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register, MEDLINE (from January 1966 to June 2006), and EMBASE (from January 1980 to June 2006) for randomised trials and contacted authors of trials and other experts in the field.

SELECTION CRITERIA

We searched for quasi-randomised or randomised controlled trials of participants with neuromuscular or chest wall disorder-related stable chronic hypoventilation of all ages and all degrees of severity, receiving any type and any mode of nocturnal mechanical ventilation. The primary outcome measure was short-term and long-term reversal of hypoventilation related clinical symptoms and secondary outcomes were unplanned hospital admission, one year mortality, short-term and long-term reversal of daytime hypercapnia, improvement of lung function and sleep breathing disorders.

DATA COLLECTION AND ANALYSIS

We identified eight randomised trials.

MAIN RESULTS

The eight eligible trials included a total of 144 participants. The relative risk of 'no improvement of hypoventilation related clinical symptoms' in the short-term following nocturnal mechanical ventilation was available in only one trial with 10 participants and was not significant, 0.09 (95% confidence interval (CI) 0.01 to 1.31). The relative risk of 'no reversal of daytime hypercapnia' in the short-term following nocturnal ventilation was significant and favoured treatment, 0.37 (95% CI 0.20 to 0.65). The weighted mean difference of nocturnal mean oxygen saturation was 5.45% (95% CI 1.47 to 9.44) more improvement in participants treated with nocturnal mechanical ventilation. For most of the outcome measures there was no significant long-term difference between nocturnal mechanical ventilation and no ventilation. However, the estimated risk of death based on three studies was reduced following nocturnal ventilation, 0.62 (95% CI 0.42 to 0.91). There was considerable and significant heterogeneity between the trials possibly related to differences between the study populations. Most of the secondary outcomes were not assessed in the eligible trials. Data from two crossover trials suggested no evidence for a difference in reversal of daytime hypercapnia and sleep study parameters between volume-cycled and pressure-cycled ventilation. No data could be summarised for the comparisons between invasive and non-invasive mechanical ventilation or between intermittent positive pressure and negative pressure ventilation.

AUTHORS' CONCLUSIONS

Current evidence about the therapeutic benefit of mechanical ventilation is weak, but consistent, suggesting alleviation of the symptoms of chronic hypoventilation in the short-term. In three small studies survival was prolonged mainly in participants with motor neuron diseases. With the exception of motor neuron disease, further larger randomised trials are needed to confirm long-term beneficial effects of nocturnal mechanical ventilation on quality of life, morbidity and mortality, to assess its cost-benefit ratio in neuromuscular and chest wall diseases and to compare the different types and modes of ventilation.

Intravenous immunoglobulin for Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome is an acute, paralysing, inflammatory peripheral nerve disease. Intravenous immunoglobulin is beneficial in other autoimmune diseases.

OBJECTIVES

We aimed to determine the efficacy of intravenous immunoglobulin for treating Guillain-Barré syndrome.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register (March 2005), MEDLINE (January 1966 to March 2005) and EMBASE (January 1980 to March 2005) using the terms 'Guillain-Barré syndrome' and 'acute polyradiculoneuritis'.

SELECTION CRITERIA

We included all randomised and quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

Two authors independently selected papers, extracted data and assessed quality.

MAIN RESULTS

Another Cochrane systematic review has shown that plasma exchange significantly hastens recovery. We found six randomised trials comparing intravenous immunoglobulin with plasma exchange. We undertook a meta-analysis of five trials involving 536, mostly adult participants who were unable to walk unaided and had been ill for less than two weeks. Our primary outcome measure was the change in a seven-grade disability scale four weeks after randomisation. The weighted mean difference of this measure was not statistically significant, being only -0.02 (95% confidence interval -0.25 to 0.20) of a disability grade more improvement in the intravenous immunoglobulin than the plasma exchange group. There were no statistically significant differences in other measures. One trial involving 249 participants compared plasma exchange followed by intravenous immunoglobulin with plasma exchange alone. Another involving 37 participants compared immunoabsorption followed by intravenous immunoglobulin with immunoabsorption alone. Neither revealed significant extra benefit from intravenous immunoglobulin. One study with 39 participants showed a trend towards more improvement with high-dose compared with low-dose intravenous immunoglobulin. Another trial with 51 children found no significant difference in outcome when the standard dose was given over two days rather than five days. Three studies including a total of 75 participants suggested that in children intravenous immunoglobulin significantly hastens recovery compared with supportive care.

AUTHORS' CONCLUSIONS

In adults, there are no adequate comparisons with placebo. Randomised trials in severe disease show that intravenous immunoglobulin started within two weeks from onset hastens recovery as much as plasma exchange, which is known to be more effective than supportive care. Treatment with intravenous immunoglobulin is significantly more likely to be completed than plasma exchange. Giving intravenous immunoglobulin after plasma exchange did not confer significant extra benefit. In children, intravenous immunoglobulin probably hastens recovery compared with supportive care alone. More research is needed in mild disease and in treatment starting more than two weeks after onset of the condition. Dose-ranging studies are also needed.

Intravenous immunoglobulin for Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome is an acute, paralysing, inflammatory peripheral nerve disease. Intravenous immunoglobulin purified from donated blood is beneficial in other autoimmune diseases.

OBJECTIVES

We aimed to determine the efficacy of intravenous immunoglobulin for treating Guillain-Barré syndrome.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group register (search updated 11 February 2003), MEDLINE and EMBASE (from January 2000 to February 2003) using Guillain-Barré syndrome and acute polyradiculoneuritis as the search terms. We also searched bibliographies of trials and made contact with their authors and other experts.

SELECTION CRITERIA

We included all randomised and quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

Two reviewers examined the titles and abstracts of all the papers retrieved by the search, extracted the data and assessed the quality of the trials independently.

MAIN RESULTS

Two trials comparing intravenous immunoglobulin with supportive treatment were inadequate to establish its value. Another Cochrane systematic review has shown that plasma exchange hastens recovery. We found six randomised trials that compared intravenous immunoglobulin with plasma exchange. In a meta-analysis of five trials involving 536, mostly adult, participants who were unable to walk unaided and had been ill for less than two weeks. The primary outcome measure in this review was the change in a seven grade disability scale four weeks after randomisation. The weighted mean difference of this measure was not statistically significant, being only 0.04 (95% CI -0.26 to 0.19) of a disability grade more improvement in the intravenous immunoglobulin group than the plasma exchange group. There were also no statistically significant differences in time to walk unaided, mortality, and proportion of participants unable to walk without aid after a year. One trial involving 249 participants compared plasma exchange followed by intravenous immunoglobulin with plasma exchange alone, and another involving 37 participants compared immunoabsorption followed by intravenous immunoglobulin with immunoabsorption alone. Neither revealed significant extra benefit from intravenous immunoglobulin. One study of only 39 participants showed a trend towards more improvement with high-dose compared with low-dose intravenous immunoglobulin.

REVIEWER'S CONCLUSIONS

Although there are no adequate comparisons with placebo, intravenous immunoglobulin hastens recovery from Guillain-Barré syndrome as much as plasma exchange. Giving intravenous immunoglobulin after plasma exchange is not significantly better than plasma exchange alone. Randomised trials are needed to decide the effect of intravenous immunoglobulin in children, in adults with mild disease and in adults who start treatment after more than two weeks.

Limitations of sniff nasal pressure in patients with severe neuromuscular weakness

BACKGROUND

Inspiratory muscle strength in patients with neuromuscular disorders can be assessed using sniff inspiratory nasal pressure (Pn(sn)) and maximum inspiratory mouth pressure (PI(max)). However, the relative merits of Pn(sn) against PI(max) are not known in patients with severe neuromuscular disease.

OBJECTIVE

To investigate whether severity of disease modifies the relation between Pn(sn) and PI(max).

METHODS

Vital capacity (VC), Pn(sn), and PI(max) were measured in 258 patients with neuromuscular disorders.

RESULTS

Data were analysed from 241 patients, 17 being unable to perform PI(max) or Pn(sn) manoeuvres. The correlation between Pn(sn) and PI(max) was +0.94 (p<0.0001), with a mean (SD) difference between Pn(sn) and PI(max) of -4.8 (21.2) cm H(2)O (the limits of agreement were 37.6 and -47.2 cm H(2)O). VC (% predicted) was positively correlated with Pn(sn)/PI(max) (r = +0.86; p<0.0001), with a lower Pn(sn)/PI(max) value in patients with a VC <40% of predicted than in those with a VC >40% (0.80 (0.35) v 1.04 (0.41); p<0.0001).

CONCLUSIONS

PI(max) is greater than Pn(sn) in patients with a severe restrictive ventilatory defect caused by neuromuscular disease. Pn(sn) may not accurately reflect inspiratory muscle strength in such patients and it is thus advisable to use both tests.

Nutritional depletion in patients on long-term oxygen therapy and/or home mechanical ventilation

The purpose of this study was to estimate the prevalence of malnutrition in outpatients on long-term oxygen therapy or home mechanical ventilation, to determine the relationships between malnutrition and impairment/disability and smoking and also to identify relevant tools for routine nutritional assessment. In 744 patients (M:F 1.68, aged 65+/-15 yrs) with chronic obstructive pulmonary disease (COPD, 40%), restrictive disorders (27%), mixed respiratory failure (15%), neuromuscular diseases (13%) and bronchiectasis (5%), body mass index (BMI), fat-free mass (FFM), serum albumin, transthyretin, 6-min walking test, forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and blood gases were recorded. FFM was the most sensitive parameter for detecting malnutrition, being abnormal in 53.6% of patients, while BMI was <20 in 23.2%, serum albumin <35 g x L(-1) in 20.7%, and serum transthyretin <200 mg x L(-1) in 20%. FFM depletion predominated in neuromuscular, bronchiectasis and restrictive disorders. BMI and FFM were correlated with FEV1, FVC and 6-min walking test. In multivariate analysis a BMI<20 was related to FEV1 and smoking habits, and a low FFM to smoking, FEV1 and female sex. Malnutrition is highly prevalent in home-assisted respiratory patients and is related to causal disease, forced expiratory volume in one second, smoking and disability. Fat-free mass appeared to be the most sensitive and relevant nutritional parameter according to impairment and disability.

[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.

[Cellular aspect of neuroinflammation in Guillain-Barré syndrome: a key to a new therapeutic option?]

Guillain-Barré syndrome (GBS) is an acute inflammatory demyelinating neuropathy associated with long-lasting morbidity and substantial risk of mortality. The two reference treatments (plasma exchange-PE and intravenous immunoglobulins-IVIGs) do not change the functional prognosis in patients with very severe disease. Pathogenesis of GBS associates recently characterized humoral and cellular immune dysfunctions. Antibodies against nerve antigens may participate in complement activation, antibody-dependent macrophage cytotoxicity, and reversible conduction failure. Cellular immune reaction is associated with an increase of proinflammatory cytokines (for exemple TNF-alpha), a decrease of anti-inflammatory cytokines (such as TGF-B1), an increase of matrix metalloproteinases (MMP-9-gelatinase B), all abnomalities favoring adhesion to and transmigration across endothelium of immune cells, a key phenomenon in GBS. Recovery of GBS is characterized by the normalization of these abnormalities. Experimental allergic neuritis (EAN), the experimental model of GBS has strikingly similar immunological abnormalities. The treatments of GBS, PE and IVIGs, mainly target the humoral component of the immune response. IFN-B is a cellular immunomodulator that inhibits antigen presentation, TNF-alpha production and binding, modulates macrophages properties. IFN-B increases anti-inflammatory T cell functions and cytokines, such as TGF-B1. IFN-B has important properties on leukodiapedesis by modulating expression of cell adhesion molecules and the MMP-9 proteinase. IFN-B has been used with success in EAN, in some patients with acute exacerbation of chronic inflammatory demyelinating polyneuropathy, and in one patient with GBS. Pathophysiology of GBS, IFN-B properties, and experimental studies support the initiation of a trial of IFN-B in GBS.

Plasma exchange for Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome is an acute symmetric, usually ascending and usually paralysing illness, due to inflammation of peripheral nerves. It is thought to be caused by autoimmune factors, such as antibodies. Plasma exchange removes antibodies and other potentially injurious factors from the blood stream. It involves connecting the patient's blood circulation to a machine which exchanges the plasma for a substitute solution, usually albumin. Several studies have evaluated plasma exchange for Guillain-Barré syndrome.

OBJECTIVES

To systematically review the evidence concerning the efficacy of plasma exchange for treating Guillain-Barré syndrome.

SEARCH STRATEGY

Search of the Cochrane Neuromuscular Disease Trial Register for randomised trials concerning plasma exchange in Guillain-Barré syndrome, search of the bibliographies of identified papers and enquiry from the authors of the papers.

SELECTION CRITERIA

Randomised and quasi-randomised trials of plasma exchange versus sham exchange or supportive treatment.

DATA COLLECTION AND ANALYSIS

Potentially relevant papers were scrutinised by two reviewers and the selection of eligible studies was agreed by them and a third reviewer. Data were extracted by one reviewer and checked by a second reviewer. Some missing data were obtained from the authors of studies.

MAIN RESULTS

Six eligible trials concerning 649 patients were identified, all comparing plasma exchange versus supportive treatment alone. Primary outcome measures ~bullet~Time to recover walking with aid In the only two trials for which this measure was reported, the median time to recover this ability was faster in the plasma exchange than the control group. ~bullet~Time to onset of motor recovery in mildly affected patients In the one trial for which this measure was available, the time was significantly shortened in the plasma exchange group. Secondary outcome measures ~bullet~Improvement in disability grade at four weeks In five trials, there were significantly more patients who had improved by one disability grade or more in the plasma exchange group as compared to the control group. Patients treated with plasma exchange fared significantly better in the following secondary outcome measures: time to recover walking without aid, percentage of patients requiring artificial ventilation, duration of ventilation, full muscle strength recovery after one year, and severe sequelae after one year. There were less patients with infectious events and cardiac arrhythmias in the plasma exchange than the control group. Subgroup analyses Plasma exchange was beneficial in patients with mild, moderate and severe (needing ventilation) Guillain-Barré syndrome. It was beneficial in patients with a disease duration of seven or less days and also in those with disease lasting more than seven days. However, in the only trial that enrolled patients up to 30 days from disease onset, the benefit of plasma exchange in patients treated after seven days was less apparent. Type of treatment Single studies showed that two plasma exchanges were significantly superior to none for mild Guillain-Barré syndrome and four to two for moderate Guillain-Barré syndrome, but that six were not superior to four for severe Guillain-Barré syndrome requiring ventilation. One study suggested that continuous flow plasma exchange was significantly superior to intermittent flow. Another study found no significant difference between the two techniques. The same study found a significantly higher rate of adverse events with fresh frozen plasma as the replacement fluid than albumin. Plasma exchange compared with cerebrospinal fluid filtration A single trial comparing these two treatments did not show any difference in outcomes but was too small to demonstrate equivalence.

REVIEWER'S CONCLUSIONS

Plasma exchange is the first and only treatment that has been proven to be superior to supportive treatment alone in Guillain-Barré syndrome. Consequently, plasma exchange should be regarded as the treatment against which new treatments, such as intravenous immunoglobulin, should be judged. In mild Guillain-Barré syndrome two sessions of plasma exchange are superior to none. In moderate Guillain-Barré syndrome four sessions are superior to two. In severe Guillain-Barré syndrome six sessions are no better than four. Continuous flow plasma exchange machines may be superior to intermittent flow machines and albumin to fresh frozen plasma as the exchange fluid. Plasma exchange is more beneficial when started within seven days after disease onset rather than later, but was still beneficial in patients treated up to 30 days after disease onset. The value of plasma exchange in children less than 12 years old is not known. There is insufficient evidence to determine whether cerebrospinal fluid filtration is equivalent to plasma exchange.

IFN-beta decreases adhesion and transmigration capacities of lymphocytes in Guillain-Barré syndrome

The adhesion capacities, transmigration capacities, and integrin expression of lymphocytes from patients with Guillain-Barré syndrome incubated with interferon-beta were studied. Interferon-beta induced a dose-dependent inhibition of lymphocyte adhesion to recombinant vascular adhesion molecule-1 (p < 0.0001) and recombinant intercellular adhesion molecule-1 (rICAM-1) (p < 0.01) without modulation of very late activation molecule-4 and lymphocyte function-associated antigen-1 expressions and a dose-dependent decrease of lymphocyte transmigration across fibronectin (p < 0.0001). Inhibition of adhesion to rICAM-1 was similar after long (18 hours) or short (5 minutes) incubation time. These results support the potential therapeutic benefit of interferon-beta in Guillain-Barré syndrome.

Cardiac variability in critically ill adults: influence of sepsis

OBJECTIVE

To evaluate, in critically ill adults, factors associated with impaired sympathovagal balance.

DESIGN

One-month inception cohort study.

SETTING

Twenty-six-bed medical intensive care unit of a teaching hospital.

PATIENTS

Critically ill adults with an expected duration of intensive care unit stay of > or =48 hrs were enrolled. Patients with permanent arrhythmia or cardiac pacing were not included.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Sympathovagal balance was assessed on the day after intensive care unit admission by the low-frequency/high-frequency ratio obtained from spectral components of heart rate signal: overall variability, low frequency, and high frequency.

RESULTS

Forty-one patients, 13 with sepsis and 28 without sepsis, were assessed. Predictors of low-frequency/high-frequency ratio with the automatic interaction detection method were sepsis and age. Binary logit analysis adjusted for age showed that sepsis remained a strong and independent factor of a low-frequency/high-frequency ratio of <1.50, with an odds ratio of 3.63 (95% confidence interval, 1.47-9.01, p =.005). Use of mechanical ventilation, catecholamines, or sedation did not add any information. The use of the low-frequency/high-frequency ratio in diagnosing sepsis may be supported by a likelihood ratio for low frequency/high frequency <1 at 6.47.

CONCLUSIONS

This work suggests that impaired cardiac variability and notably sympathovagal balance (i.e., a low-frequency/high-frequency ratio <1.0) may be a diagnostic test for sepsis.

Inhibition of the adhesion step of leukodiapedesis: a critical event in the recovery of Guillain-Barré syndrome associated with accumulation of proteolytically active lymphocytes in blood

Intraneural inflammation, that reflects emigration of immune cells from blood to nerve tissue, is a critical event in Guillain-Barré syndrome pathogenesis. To investigate the adhesion and transmigration phases of leukodiapedesis, we determined in a series of patients with GBS: (1) circulating levels of soluble forms of adhesion molecules (sICAM-1 and sVCAM-1); (2) attachment capacities of circulating lymphocytes to rICAM-1 and rVCAM-1; (3) fibronectin-penetrating capacities of circulating lymphocytes; and (4) lymphocyte intracellular concentrations of MMP-9 at the different phases of GBS and in healthy controls. Circulating levels of sVCAM-1 and sICAM-1 were above normal values at the time of progression, markedly increased at the time of plateau (sVCAM-1: P<0.03; sICAM-1: P<0.02), and tended to normalize during recovery. The percentage of cells with attachment capacities to rVCAM-1 and to rICAM-1 decreased from progression to recovery by 30 and 31%, respectively (P<0.02). The number of circulating lymphocytes with fibronectin penetrating capacities was lower than controls at the time of progression (P<0.01), then progressively increased to reach values higher than controls at the time of late recovery (P<0.02). Cellular concentrations of MMP-9 in circulating lymphocytes paralleled their fibronectin penetrating capacities. These results suggest early emigration of lymphocytes into nerve, followed by shedding of adhesion molecules from endothelium, and late decrease of lymphocyte adhesion capacities. Plateau and recovery are associated with accumulation in the vascular compartment of still proteolytically active lymphocytes that can no longer adhere to endothelial cells. Modulation of the adhesion step of leukodiapedesis may be crucially involved in the switch from progression to plateau of GBS.

Supine fall in lung volumes in the assessment of diaphragmatic weakness in neuromuscular disorders

OBJECTIVE

To determine whether diaphragmatic function can be determined by noninvasive respiratory indices in neuromuscular disease.

DESIGN

Vital capacity (VC) and mouth pressure generated during a maximal static inspiratory effort (Pi max) were measured with patients in both sitting and supine positions.

SETTING

Rehabilitation hospital.

PATIENTS

Twenty-four patients with generalized neuromuscular disease.

MAIN OUTCOME MEASURES

Changes in indices from sitting to supine position were compared with invasive diaphragmatic function indices consisting of transdiaphragmatic pressures during maximal sniff (Pdi sniff) and the ratio of gastric pressure (Pga) increases over transdiaphragmatic pressure (DeltaPga/DeltaPdi) during quiet breathing.

RESULTS

The fall in VC in the supine position was greater in the 15 patients who had spontaneous paradoxical diaphragmatic motion (DeltaPga/DeltaPdi < 0) than in the 9 patients who did not. Specificity and sensitivity of a greater than 25% supine fall in VC for the diagnosis of diaphragmatic weakness (DeltaPga/DeltaPdi < 0 and/or Pdi sniff < 30cmH2O) were 90% and 79%, respectively. Stepwise multiple regression analysis of Pdi sniff showed that both the supine fall in VC and Pi max were associated with diaphragmatic weakness (R(2) =.66; p <.0001). These factors contributed 52% and 14% of the Pdi sniff variance, respectively.

CONCLUSIONS

Simple VC measurement in the sitting and supine positions may be helpful in detecting severe or predominant diaphragmatic weakness.

Intravenous immunoglobulin for Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome is a potentially serious, acute, paralysing, probably autoimmune disease caused by inflammation of the peripheral nerves. Recovery has been shown to be speeded by plasma exchange which replaces the patient's own plasma with a plasma substitute. Intravenous immunoglobulin purified from donated blood is beneficial in other autoimmune diseases and is easier to administer.

OBJECTIVES

To determine the efficacy of intravenous immunoglobulin in comparison with no treatment or other treatments for treating Guillain-Barré syndrome and to determine the most efficacious dose.

SEARCH STRATEGY

Search of the Cochrane Neuromuscular Disease Group register using Guillain-Barré syndrome and acute polyradiculoneuritis as the search terms, bibliographies of trials and contact with their authors and other experts.

SELECTION CRITERIA

Randomised and quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

Two reviewers examined the titles and abstracts of all the papers retrieved by the search, extracted the data onto forms designed for this review, and independently assessed the quality of the trials.

MAIN RESULTS

The only trial comparing intravenous immunoglobulin with supportive treatment was inadequate to establish its value. Another Cochrane systematic review has shown that plasma exchange (PE) hastens recovery. Plasma exchange has become the gold standard against which other treatments need to be compared. We found three randomised trials that compared intravenous immunoglobulin with PE. We were able to combine the results of the two largest trials in a metaanalysis involving 398 patients. The primary outcome measure in this review was the change in a 7 grade disability scale four weeks after randomisation. The weighted mean difference of this measure was not significant, being only 0.11 (95% CI -0.14 to 0.37) of a disability grade more improvement in the intravenous immunoglobulin group than the PE group. There were also no significant differences in other outcome measures, including time to walk unaided, mortality, and proportion of patients unable to walk without aid after a year but some of these outcome measures were only available for one trial. We also reviewed one trial involving 249 patients which compared PE followed by intravenous immunoglobulin with PE alone and another involving 37 patients which compared immunoabsorption followed by intravenous immunoglobulin with immunoabsorption alone. Neither revealed any significant differences between the regimens with and without intravenous immunoglobulin. We did not discover any dose ranging studies of intravenous immunoglobulin except for one that is ongoing.

REVIEWER'S CONCLUSIONS

There are no adequate trials to determine whether intravenous immunoglobulin is more beneficial than placebo. Intravenous immunoglobulin and plasma exchange have a similar ability to speed the recovery from Guillain-Barré syndrome. Giving intravenous immunoglobulin after plasma exchange is not significantly better than plasma exchange alone. Randomised trials are needed to decide whether intravenous immunoglobulin helps in mild Guillain-Barré syndrome or in disease which has lasted more than two weeks. Randomised trials also need to establish the optimal dose.

Cost analysis of plasma-exchange therapy for the treatment of Guillain-Barré syndrome. French Cooperative Group on Plasma Exchange in Guillain-Barré Syndrome

OBJECTIVE

To undertake a cost analysis of therapeutic strategies with plasma exchange (PE) for the treatment of patients with Guillain-Barré syndrome.

DESIGN

A randomized clinical trial including 556 patients with Guillain-Barré syndrome. We demonstrated that in the group with mild disease (walking possible) two PEs were more effective than none in shortening the time to beginning motor recovery. In the groups with moderate disease (walking impossible) and or severe disease (mechanically ventilated patients) four sessions were more effective than two and no more effective than six in shortening the time to recovery of walking with assistance and for the recovery rate of full muscle strength within 1 year. Data on outcomes and costs was collected. Complete cost data were available on 546 from the 556 patients of the trial. Costs were estimated from the viewpoint of the healthcare system and computed over a 1-year period. Because the analysis of medical outcomes did not show any difference regarding mortality but only on intermediate short-term and long-term outcomes, we carried out a cost minimization analysis.

RESULTS

In two groups a dominant strategy appeared, with greater efficacy and lower costs in the two-PE arm for the mild group: 21,353 euros vs. 38,753 euros and in the four-PE arm in the moderate group: 59,480 euros vs. 80,737 euros. In the severe group four PEs were as efficient and somewhat less expensive than six: 57,621 vs. 61,056 euros.

CONCLUSION

The treatment of Guillain-Barré syndrome by PE at the onset of disease appears to have medical justification. The least expensive strategies are either more or equally efficient as more expensive strategies.

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.

[Guillain-Barré syndrome: epidemiological, clinical and therapeutic insight]

The average annual incidence of Guillain-Barré syndrome is 1.5 per 100 000. Mortality was about 5% in a recent clinical trial. Ten percent of patients have severe neurological sequelae one year after onset. For these patients, general care is essential and should be provided in appropriate hospital units. Corticosteroids, administered orally or intravenously are ineffective. Plasma exchange (PE) was the first treatment to demonstrate efficacy in randomized clinical trials. Indications have been recently specified. Patients who can walk must be given two PEs and two additional PEs in case of aggravation. Four plasma exchanges are sufficient in patients unable to walk unaided (intermediate form) or who are mechanically ventilated (severe form). No further PE is required if the patient fails to improve. High-dose intravenous immunoglobulins (0.4 g /kg daily for 5 days) and PE have equivalent efficacy in intermediate and severe forms. The optimal dose of IVIg and the number of Pes in the different severity forms are being assessed in an ongoing study.

Compartmentalised inducible nitric-oxide synthase activity in septic shock

BACKGROUND

Previous experimental studies support a role for inducible nitric-oxide synthase (iNOS) in the pathogenesis of severe sepsis. The aim of the study was to characterise iNOS activity in different tissues in patients with septic shock.

METHODS

13 consecutive patients with septic shock caused by cellulitis were enrolled. Skin, muscle, fat, and artery samples were obtained from normal, inflamed, and putrescent areas to measure iNOS activity, and concentrations of tumour necrosis factor alpha (TNFalpha) and interleukin 1beta (IL-1beta). In two patients, iNOS activity was also assessed in peripheral blood mononuclear cells (PBMC) incubated with microorganisms causing the sepsis, or in macrophages isolated from suppurating peritoneal fluid incubated with IL-1beta.

FINDINGS

Compared with normal and inflamed areas, iNOS activity was increased in putrescent areas for muscle (71-fold [95% CI 20-259] vs normal areas, 69-fold [19-246] vs inflamed areas; p<0.01 for each) and for fat (68-fold [23-199] and 49-fold [18-137], respectively; p<0.01), but not for skin. Compared with normal areas, putrescent areas of arteries showed increased iNOS expression (1280-fold [598-3153]; p<0.01). Compared with normal areas, TNFalpha and IL-1beta were increased in putrescent areas of arteries (223-fold and 41-fold, respectively; p<0.01 for each). PBMCs and tissue macrophages expressed iNOS. Plasma nitrite/nitrate concentrations inversely correlated with mean arterial pressure and systemic vascular resistance.

INTERPRETATION

In human septic shock we found that iNOS activity is compartmentalised at the very site of infection and parallels expression of TNFalpha and IL-1beta. PBMCs and tissue macrophages can be a cellular source for iNOS.

A 3-level prognostic classification in septic shock based on cortisol levels and cortisol response to corticotropin

CONTEXT

The hypothalamic-pituitary-adrenal axis is a major determinant of the host response to stress. The relationship between its activation and patient outcome is not known.

OBJECTIVE

To evaluate the prognostic value of cortisol levels and a short corticotropin stimulation test in patients with septic shock.

DESIGN AND SETTING

Prospective inception cohort study conducted between October 1991 and September 1995 in 2 teaching hospital adult intensive care units in France.

PARTICIPANTS

A total of 189 consecutive patients who met clinical criteria for septic shock.

INTERVENTION

A short corticotropin stimulation test was performed in all patients by intravenously injecting 0.25 mg of tetracosactrin; blood samples were taken immediately before the test (T0) and 30 (T30) and 60 (T60) minutes afterward.

MAIN OUTCOME MEASURES

Twenty-eight-day mortality as a function of variables collected at the onset of septic shock, including cortisol levels before the corticotropin test and the cortisol response to corticotropin (delta max, defined as the difference between T0 and the highest value between T30 and T60).

RESULTS

The 28-day mortality was 58% (95% confidence interval [CI], 51%-65%) and median time to death was 17 days (95% CI, 14-27 days). In multivariate analysis, independent predictors of death (P < or = .001 for all) were McCabe score greater than 0, organ system failure score greater than 2, arterial lactate level greater than 2.8 mmol/L, ratio of PaO2 to fraction of inspired oxygen no more than 160 mm Hg, cortisol level at T0 greater than 34 microg/dL and delta max no more than 9 microg/dL. Three groups of patient prognoses were identified: good (cortisol level at T0 < or = 34 microg/dL and delta max > 9 microg/dL; 28-day mortality rate, 26%), intermediate (cortisol level at T0 34 microg/dL and delta max < or = 9 microg/dL or cortisol level at T0 > 34 microg/dL and delta max > 9 microg/dL; 28-day mortality rate, 67%), and poor (cortisol level at T0 > 34 microg/dL and delta max < or = 9 microg/dL; 28-day mortality rate, 82%).

CONCLUSION

Our data suggest that a short corticotropin test has a good prognostic value and could be helpful in identifying patients with septic shock at high risk for death.

Matrix metalloproteinase-9 is increased and correlates with severity in Guillain-Barré syndrome

OBJECTIVE

To study the expression and activity of matrix metalloproteinases (MMPs) MMP-2 (72-kd type IV collagenase, gelatinase A), MMP-3 (58-kd stromelysin-1), and MMP-9 (92-kd type IV collagenase, gelatinase B) and tissue inhibitors of MPs (TIMP) in patients with Guillain-Barre syndrome (GBS).

BACKGROUND

MMPs are able to proteolysis of basement membranes and other matrix components, promoting transmigration of inflammatory cells from circulation to nerve tissue.

METHODS

Twenty-five patients with GBS were analyzed according to the phase of the disease, i.e., progression, plateau, early recovery, and late recovery. Determinations of MMP-2, MMP-3, MMP-9, and TIMP-1 were performed using ELISA, zymography, and immunocytochemistry in circulation or peripheral nerve.

RESULTS

MMP-9 plasma levels were increased in 67% of patients on admission and decreased from progression to late recovery (p < 0.002). During the course of GBS, MMP-9 was progressively balanced by its inhibitor TIMP-1, as assessed by the MMP-9/TIMP-1 ratio. MMP-9 and TIMP-1 plasma levels and the MMP-9/TIMP-1 ratio correlated positively with disability. MMP-2 expression was similar to controls. MMP-3 activity was not detected, and plasma levels were not different from those in controls. Positive MMP-9 immunolabeling was 51 +/- 11% of circulating lymphocytes. It was observed in some endothelial cells and mononuclear cells adherent to the endothelium and close to myelinated fibers.

CONCLUSIONS

Circulating matrix metalloproteinases (MMP-9) correlates with disease severity in Guillain-Barré syndrome (GBS). MMP-9 likely represents an important molecule in the pathogenesis of GBS and therefore could represent an interesting therapeutic target.

Short-term variability of blood pressure and heart rate in Guillain-Barré syndrome without respiratory failure

The effect of Guillain-Barré syndrome (GBS) on the short-term variability of blood pressure and heart rate was evaluated in six patients presenting with a moderate form of the syndrome, i.e. unable to stand up unaided and without respiratory failure, at the height of the disease and during recovery. The patients were compared with six age-matched healthy volunteers. During the acute phase of the syndrome, GBS patients exhibited a significant heart rate elevation (+26 beats/min compared with healthy subjects), but the acceleratory response to atropine, or to 60 degrees head-up tilt, was maintained. Resting plasma noradrenaline levels were high in acute GBS, but the secretory response to tilt was preserved. Desensitization to noradrenaline was observed in acute GBS with a reduced pressor action of this alpha-adrenoceptor agonist. Blood pressure levels were normal and head-up tilt did not induce orthostatic hypotension in this moderate form of GBS. Power spectral analysis demonstrated marked alterations in cardiovascular variability. The overall heart period variability was markedly reduced with the reduction predominantly in the high-frequency (respiratory) range (-73%). The low-frequency component of heart period variability was also reduced (-54%). This cardiovascular profile of moderate GBS at the height of the disease could result from a demyelination of the reflex loop controlling respiratory oscillations in heart rate and from a desensitization of the arterial tree to an elevated plasma noradrenaline. Sympathetic nervous activation may contribute to the high resting heart rate in acute GBS.

Is early noninvasive mechanical ventilation of first choice in stable restrictive patients with chronic respiratory failure?

Noninvasive long-term ventilation is consensually advocated when daytime hypercapnia > 6 kPa at steady state in chronic restrictive pulmonary syndromes. Several mechanisms can cause the occurrence of hypercapnia in these diseases. They may involve impairment of lung mechanics or airway function and cough, ventilation-perfusion mismatching, blunted central ventilatory drive or respiratory muscle fatigue. These abnormalities may occur while awake or during sleep. From a practical point of view, imperative ventilation, a palliative technique that aims to supply respiratory muscle weakness, and preventive ventilation, aimed at delaying respiratory handicap, should be distinguished between. The latter is offered to patients who do not fulfil any criteria for mechanical ventilation. Otherwise, the underlying disease markedly influences both pathophysiology and outcome. This implies that the available modes of ventilatory support should be assessed in each disease. Several findings have been published about Duchenne's muscular dystrophy. Mechanical ventilation, usually using noninvasive methods, is offered to patients with either hypercapnia or a forced vital capacity < 20% of the predicted value. Nevertheless, based on our experience, deterioration of the restrictive syndrome should be followed by a tracheostomy. By contrast, early ventilation, offered to patients free of symptoms and whose forced vital capacity are within 20-50% pred and with normal arterial blood gas levels, achieves no benefit.

[Waiting for the end of poliomyelitis. Setting of the last phase of the eradication program. National Commission for the Certification of the Eradication of Poliomyelitis]

The worldwide eradication of poliomyelitis is expected within a few years. A reinforcement of epidemiological, clinical and viral supervision is necessary. Besides a sustained immunization effort, particular attention is required from all clinicians concerning the cases of non-traumatic acute flacid palsy that they may observe. In these cases it is asked to clinicians to perform a search for enterovirus in stool and spinal fluid, and a poliomyelitis serology.

[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.

Circulating transforming growth factor beta 1 (TGF-beta1) in Guillain-Barré syndrome: decreased concentrations in the early course and increase with motor function

OBJECTIVE

To delineate the possible implication of the immunosuppressive cytokine transforming growth factor beta 1 (TGF-beta1) in the pathogenesis of Guillain-Barré syndrome. Guillain-Barré syndrome is a disorder that may implicate cytokines in its pathogenesis. TGF-beta1 is a potent anti-inflammatory cytokine occasionally shown to be regulated in the course of demyelinating disorders.

METHODS

The study measured circulating proinflammatory and anti-inflammatory cytokines from the progressing phase to early recovery in patients with Guillain-Barré syndrome. Plasma concentrations of TNF-alpha, IL-beta1, IL-2, IL-4, IL-6, IL-10, and TGF-beta1 were prospectively evaluated in 15 patients with Guillain-Barré syndrome every three days for the first 15 days after admission to hospital, and in 15 controls with non-inflammatory neurological diseases.

RESULTS

Concentrations of TGF-beta1 in plasma were decreased in 13115 patients (87 %) at day 1, remained low during progression and the plateau of paralysis (days 1-10), and then progressively increased up to control concentrations during early recovery (days 12-15). Concentrations of plasma TGF-beta1 correlated positively with motor function, the lowest values being e found in the most disabled patients. Concentrations of plasma TGF-beta1 were decreased before any treatment, and during treatment by either plasma exchange or intravenous immunoglobulins, plasma exchange being associated with a more pronounced decrease in TGF-beta1 at day 7. Circulating TNF-alpha concentrations were raised, as previously reported, when other cytokines were either randomly increased (IL-2, IL-6), or undetectable (IL-1, IL-4, IL-7, IL-10).

CONCLUSIONS

Down regulation of TGF-beta1 in the early course of Guillain-Barré syndrome could participate in neural inflammation.

[Respective indications of plasma exchange and high-dose immunoglobulins in polyradiculoneuritis and myasthenia gravis]

The main purpose of plasma exchange is to remove toxic substances. The mechanisms involved appear to be complex. The primary aim of immunoglobulins is to compensate for immunodeficiency, but when given intravenously at high doses, immunoglobulins can also have unexpected immunomodulation effects. Routine therapeutic use of these methods raises the problem of cost and potential morbidity. Two therapeutic trials have demonstrated that plasma exchange in Guillain-Barré syndrome improves outcome when given early. In chronic polyradiculonevritis, plasma exchange and intravenous immunoglobulins have been shown to be equally effective although plasma exchange would give less satisfactory results in patients with polyradiculonevritis and monoclonal IgG. The effect of intravenous immunoglobulins is being evaluated. Plasma exchange has become the gold standard for acute crisis of myasthenia gravis. Recent results suggest that intravenous immunoglobulins could be equally effective in these diseases. Though useful therapeutic tools, the respective indications and optimal doses for these methods remains to be defined.

Circulating tumor necrosis factor (TNF)-alpha and soluble TNF-alpha receptors in patients with Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an inflammatory disorder that may implicate proinflammatory cytokines such as TNF-alpha in its pathogenesis. We determined serum levels of TNF-alpha and the specific antagonists sTNF-Rs p55 and p75 in 24 patients with GBS at days 1, 15 and 30 of hospitalization. Patients were in the progression phase of the disease at day 1, and in the recovery phase at day 30. They were classified as able to walk (stage A), confined to bed (B), or under assisted ventilation (C). All patients underwent plasma exchange within day 1-12. At day 1, TNF-alpha levels were elevated in 15/24 patients, and sTNF-Rs were elevated in 21/23. TNF-alpha levels had not decreased at day 15, and dropped at day 30 (p < 0.04), whereas sTNF-R p55 remained elevated at day 15 and day 30. The TNF-alpha/sTNF-Rs ratio, estimating active TNF-alpha unbound to sTNF-Rs, decreased from day 1 to day 30 (p < 0.05). A positive correlation was found between disease severity and sTNF-R serum levels (p < 0.01). In conclusion, elevated circulating sTNF-Rs assesses activation of the TNF-alpha system in almost all patients with GBS and correlates positively with disease severity. Drop of TNF-alpha contrasting with sustained elevation of sTNF-R p55 during recovery suggests that sTNF-R p55 may be important in the fading of the neural inflammatory effect of TNF-alpha in GBS.

Kinetics of elimination and acute consequences of cerebral air embolism

The pathophysiology of arterial air embolism inducing brain injuries remains unclear. Previous experiments demonstrated the usefulness of computed tomography (CT) in the detection of air emboli in canine brain. This canine study investigates CT's ability to detect small air bubbles and to determine the kinetics of air elimination from cerebral arteries and its relationship with clinical, electroencephalographic (EEG), and histological manifestations. CT detects small air embolism, and intracerebral air volume strongly correlates with injected air dose (r2 = 0.86, p = 2 x 10(-3)). Air clearance time significantly depends on intracerebral air volume (r2 = 0.86, p = 0.04) and on the number of bubbles (r2 = 0.71, p = 0.03), whereas half-life of air elimination does not. No relationship was found between injected air dose, air clearance time, intracerebral volume of air, and clinical, EEG, and histological findings. The data indicate that CT accurately detects small air bubbles in the early course of cerebral air embolism, that air elimination from cerebral arteries follows a first-order compartment model, and that early CT findings do not correlate with clinical, EEG, and histological manifestations.

Effects of mechanical ventilation with normobaric oxygen therapy on the rate of air removal from cerebral arteries

OBJECTIVE

We conducted the current study to evaluate the removal rate of air embolism from cerebral arteries after spontaneous breathing at a low FIO2 in comparison with mechanical ventilation at an FIO2 of 1.0.

DESIGN

Randomized, experimental trial.

SETTING

Neuroimaging department at a veterinary school hospital laboratory.

SUBJECTS

Nine anesthetized beagles undergoing mechanical ventilation with previous normal cranial computed tomography (CT) scan.

INTERVENTIONS

In each dog, after a control scan, air was infused at a constant flow rate, via a catheter inserted into the internal carotid artery. CT scan was repeated until typical bubbles appeared. Immediately after, the animals were randomly assigned to breathe room air (group A), or to be mechanically ventilated at an FIO2 of 1.0 (group B). CT scan was again repeated every minute until the removal of all bubbles. We compared the volume of air infused per kg of body and brain weights, the lowest density among bubbles (Hounsfield units), the duration of radiologic findings, and the ratio of volume/duration (mL/kg/min) between the two groups, using the Mann-Whitney test.

RESULTS

The volume of air infused per kg of body and brain weights and density were not significantly different between the two groups. The duration of radiologic findings was shorter (p < .02) in group B (7.0 +/- 4.7) than in group A (20.4 +/- 3.8), and the air removal rate from cerebral arteries (expressed as volume/duration of radiologic findings) was dramatically improved (p < .02) in group B (0.159 +/- 0.042) in comparison with group A (0.046 +/- 0.016).

CONCLUSIONS

These results suggest that the removal rate of air from cerebral arteries is dramatically increased by mechanical ventilation at an FIO2 of 1.0. Consequently, the time of cerebral ischemia may be decreased, but the result does not account for the effects of each factor separately. Further studies are required to evaluate the clinical benefits of high FIO2 administration and of mechanical ventilation separately. However, the prompt application of mechanical ventilation with an FIO2 of 1.0 may be recommended when air embolism is suspected.

[Importance of evoked potentials in the evolutive prognosis of coma during cerebral anoxia in adults]

Ten cases of postanoxic coma have been studied. A clinical neurological examination with study of brainstem reflexes and the EEG recording were made on the first day (J1), the third day (J3) and the tenth day (J10) after the start of the coma. A recording of the visual evoked potentials, the brainstem evoked potentials and the somatosensory potentials combined was made at the same time. A clinical examination is carried out one month after the coma when the patient survives. According to the initial clinical examination, we distinguished 3 groups of subjects. The results show that in group III the visual evoked potentials such as EEG have a slightly significant prognostic value; frequently the near outcome lead to death whereas EEG activity persists and the visual evoked potentials disappear later. On the other hand, the association of brainstem evoked potentials and somatosensory potentials clearly has a higher prognostic value in this group. The disappearance of the shortest brainstem responses and the cortical somatosensory responses is clearly an unfavourable prognosis. This disappearance associated with the end EEG activity is the absolute proof of brain death. On the other hand, the persistence of these responses is of a better prognosis at least on the survival level, but their degradation during evolution is unfavourable.

[Value of lower limb arteriography in iatrogenic ergotism. A report on a case (author's transl)]

The authors report a further case of ergotamine poisoning with acute ischemia of the four limbs. Arteriography was carried out during the course of the vascular accident and at a later period when clinical signs had disappeared. Arteriography confirmed the presence of diffuse vascular spasm appearing as thin filiform arteries without any signs of a collateral circulation. Normal conditions were restored in the iliac, femoral, and leg arteries after stopping ergotamine administration. Arteriography appears to be of great value when there is any doubt during the acute clinical stage, in order to assist diagnosis and to confirm and verify the integrity of the vascular network at a later stage.

[Gram negative bacillus septicemias. Results of treatment of 31 gram negative bacillus septicemias using intravenous nalidixic acid]

Enterobacteria multiresistant to usual antibiotics, often remain sensitive to nalidixic acid, sometimes as a result of synergy with polymixins. Use of the intravenous route makes it possible to obtain more than adequate serum levels. Pharmacological study has indicated appropriate doses in terms of renal function. Intravenous nalidixic acid has been used in the treatment of 31 cases of Gram negative septicaemia, with success in 22. These results are all the more significant given that the patients were all seriously ill, cultures having grown multiresistant organisms and that nalidixic acid was used only after other antibiotics had failed.