Andrea Candiani

Simplified electrophysiological evaluation of peripheral nerves in critically ill patients: the Italian multi-centre CRIMYNE study

IntroductionCritical illness myopathy and/or neuropathy (CRIMYNE) is frequent in intensive care unit (ICU) patients. Although complete electrophysiological tests of peripheral nerves and muscles are essential to diagnose it, they are time-consuming, precluding extensive use in daily ICU practice. We evaluated whether a simplified electrophysiological investigation of only two nerves could be used as an alternative to complete electrophysiological tests.MethodsIn this prospective, multi-centre study, 92 ICU patients were subjected to unilateral daily measurements of the action potential amplitude of the sural and peroneal nerves (compound muscle action potential [CMAP]). After the first ten days, complete electrophysiological investigations were carried out weekly until ICU discharge or death. At hospital discharge, complete neurological and electrophysiological investigations were performed.ResultsElectrophysiological signs of CRIMYNE occurred in 28 patients (30.4%, 95% confidence interval [CI] 21.9% to 40.4%). A unilateral peroneal CMAP reduction of more than two standard deviations of normal value showed the best combination of sensitivity (100%) and specificity (67%) in diagnosing CRIMYNE. All patients developed the electrophysiological signs of CRIMYNE within 13 days of ICU admission. Median time from ICU admission to CRIMYNE was six days (95% CI five to nine days). In 10 patients, the amplitude of the nerve action potential dropped progressively over a median of 3.0 days, and in 18 patients it dropped abruptly within 24 hours. Multi-organ failure occurred in 21 patients (22.8%, 95% CI 15.4% to 32.4%) and was strongly associated with CRIMYNE (odds ratio 4.58, 95% CI 1.64 to 12.81). Six patients with CRIMYNE died: three in the ICU and three after ICU discharge. Hospital mortality was similar in patients with and without CRIMYNE (21.4% and 17.2%; p = 0.771). At ICU discharge, electrophysiological signs of CRIMYNE persisted in 18 (64.3%) of 28 patients. At hospital discharge, diagnoses in the 15 survivors were critical illness myopathy (CIM) in six cases, critical illness polyneuropathy (CIP) in four, combined CIP and CIM in three, and undetermined in two.ConclusionA peroneal CMAP reduction below two standard deviations of normal value accurately identifies patients with CRIMYNE. These should have full neurological and neurophysiological evaluations before discharge from the acute hospital.

Role of the infectious diseases specialist consultant on the appropriateness of antimicrobial therapy prescription in an intensive care unit

BACKGROUND Use of routine microbiologic surveillance, antibiotic practice guidelines, and infectious diseases (ID) specialist consultation might contribute to achieve an early diagnosis and an appropriate antibiotic treatment of infections, particularly in an intensive care unit (ICU) setting. METHODS We conducted a prospective cohort study in an ICU over a period of 4 years (2001-2004). We studied all patients with a possible or definite diagnosis of infection who received antimicrobial treatment, analyzing the appropriateness of antimicrobial therapy prescription before (P1) and after (P2) the implementation (January 1, 2003) of a systematic ID specialist consultation program. RESULTS Among the 349 patients enrolled, we observed 205 infections during P1 and 197 during P2. Infections treated with appropriate antimicrobial therapy were 141 (68.8%) in P1 and 165 (83.7%) in P2 (P .0004). Compliance to the local guidelines for empirical antimicrobial therapy increased by 20.4% from P1 to P2 (P < .0001). Patients receiving an appropriate treatment had a significantly shorter duration of antibiotic treatment (P < .0001), mechanical ventilation (P < .0001), ICU stay (P < .0001), and reduced in-hospital mortality (P = .006). Adherence to local antibiotic therapy guidelines improved significantly from P1 (63.4%) to P2 (83.8%) (P < .0001). CONCLUSION The introduction of an ID specialist consultation program may improve the appropriateness of the antimicrobial therapy prescription in ICU and the adherence to the local antibiotic therapy guidelines. Furthermore, appropriate antibiotic therapy is associated with a reduction in both ICU and in-hospital mortality.

Acute neuromuscular respiratory failure after ICU discharge

Objective: To describe a syndrome of acute neuromuscular respiratory failure (NM-ARF) caused by ICU-acquired acute myopathy and neuropathy.¶Design: Case series.¶Setting: General Regional University Hospital in Brescia, Italy.¶Patients: Five adult patients with NM-ARF after prolonged ICU stay and successful weaning from the ventilator and ICU discharge.¶Interventions: None.¶Measurements: Clinical signs of NM-ARF, electroneurography and electromyography (ENMG) of peripheral nerves and muscles, and functional assessment of respiratory muscles.¶Results: NM-ARF was diagnosed at the time of (one case), or 1–3 days after, ICU discharge. Limb weakness alarmed the physicians, while the signs of the NM-ARF were initially undetected. In the first observed case the acute respiratory failure was near fatal, and necessitated ICU readmission, while in the other cases 2 weeks of aggressive chest physiotherapy permitted resolution of the respiratory failure. History, clinical course and ENMG indicated the diagnosis of critical illness myopathy and neuropathy (CRIMYNE). Three patients recovered fully, while two had persisting evidence of axonal polyneuropathy several months after the onset.¶Conclusions: Critically ill patients with prolonged ICU stay, sepsis and MOF are at great risk of developing CRIMYNE, which in turn may be responsible for NM-ARF. This latter complication may arise after resolution of the respiratory and cardiac dysfunctions and successful weaning from the ventilator. As NM-ARF may cause unplanned ICU readmission or even unexpected death, strict clinical surveillance and monitoring of respiratory muscle function is recommended after discharge to the general ward of patients with proven NM-ARF. Early intensive chest physiotherapy can resolve the condition.

Quality of reporting of randomised controlled trials in the intensive care literature. A systematic analysis of papers published in Intensive Care Medicine over 26 years.

AbstractObjective. To assess the number and quality of the reporting of randomised controlled trials (RCTs) published in Intensive Care Medicine. Design. Systematic revision. Setting Randomised controlled trials published in Intensive Care Medicine. Study selection. All RCTs published in this journal from its birth to December 2000 identified by MEDLINE and our own research. Measurements and results. The Jadad scale and the individual assessment of key methodological components, namely the randomisation process, blinding and reporting and handling of loss to follow-up, were used to evaluate the quality of reporting. Other information was extracted regarding the design characteristics and the analytical approach. 173 RCTs, 63% of which were from European countries, were analysed. Adequately reported RCTs according to a Jadad scale score of more than 2 were 44 (25.4%). Analysis of individual methodological components revealed a variable percentage of adequate reporting ranging from 3.5% for randomisation to 10.4% for blinding and to 49.1% for loss to follow-up. Sample sizes were small with a median of 30 patients and rationale for its estimation was reported in 7.5%. Despite this, 81.5% of RCTs reported statistically significant results, suggesting that the treatment effects were strong or that a publication bias existed or that the uncertainty principle was not fulfilled. Conclusions. Randomised controlled trials offer the best evidence of the efficacy of medical interventions, provided that high standards of transparent reporting are used. More resolute attention to the methodological quality of reporting and adherence to recently published guidelines (CONSORT II) may help to achieve this result.

Bedside burr hole for intracranial pressure monitoring performed by intensive care physicians. A 5-year experience

ObjectiveTo assess the results of a 5-year experience with bedside burr hole for intracranial pressure (ICP) monitoring performed by intensive care physicians.DesignProspective, observational study in 120 patients.SettingA general-neurologic Intensive Care Unit in a University Hospital.PatientsPatients admitted for acute neural lesion requiring ICP monitoring.MethodA 2.71 mm burr hole was made with positioning of a subarachnoid screw, through which a miniaturized fiberoptic, tip transducer device (Camino) was advanced and inserted 2 mm in the frontal cortex.Main resultsOver a 5-year peroid 120 patients, mainly with severe head trauma, underwent ICP monitoring. None of the planned patients was excluded because of technical difficulties. No life-threatening complications were reported, and the overall morbidity rate related to the ICP monitor was 3.35. Complications were infectious in nature, with 2.55 wound infections and 0.8% meningitis. Although seven patients bled when opening the dura, no intracranial hematomas were recorded due to the ICP monitor. The fiberoptic device was left in place for 5±1.6 (SD) days (range 1–12 days). Five patients (4.1%) required catheter substitution due to breakage of the system components (fiberoptics).ConclusionsBedside insertion of a ICP monitor performed by intensive care physicians is a safe procedure, with a complication rate comparable to other series published by neurosurgeons. The overall morbidity rate is comparable to, or even lower than, that caused by central vein catheterization.

In vitro and in vivo evaluation of a new active heat moisture exchanger

IntroductionIn order to improve the efficiency of heat moisture exchangers (HMEs), new hybrid humidifiers (active HMEs) that add water and heat to HMEs have been developed. In this study we evaluated the efficiency, both in vitro and in vivo, of a new active HME (the Performer; StarMed, Mirandola, Italy) as compared with that of existing HMEs (Hygroster and Hygrobac; Mallinckrodt, Mirandola, Italy).MethodsWe tested the efficiency by measuring the temperature and absolute humidity (AH) in vitro using a test lung ventilated at three levels of minute ventilation (5, 10 and 15 l/min) and at two tidal volumes (0.5 and 1 l), and in vivo in 42 patients with acute lung injury (arterial oxygen tension/fractional inspired oxygen ratio 283 ± 72 mmHg). We also evaluated the efficiency in vivo after 12 hours.ResultsIn vitro, passive Performer and Hygrobac had higher airway temperature and AH (29.2 ± 0.7°C and 29.2 ± 0.5°C, [P < 0.05]; AH: 28.9 ± 1.6 mgH2O/l and 28.1 ± 0.8 mgH2O/l, [P < 0.05]) than did Hygroster (airway temperature: 28.1 ± 0.3°C [P < 0.05]; AH: 27 ± 1.2 mgH2O/l [P < 0.05]). Both devices suffered a loss of efficiency at the highest minute ventilation and tidal volume, and at the lowest minute ventilation. Active Performer had higher airway temperature and AH (31.9 ± 0.3°C and 34.3 ± 0.6 mgH2O/l; [P < 0.05]) than did Hygrobac and Hygroster, and was not influenced by minute ventilation or tidal volume. In vivo, the efficiency of passive Performer was similar to that of Hygrobac but better than Hygroster, whereas Active Performer was better than both. The active Performer exhibited good efficiency when used for up to 12 hours in vivo.ConclusionThis study showed that active Performer may provide adequate conditioning of inspired gases, both as a passive and as an active device.

The early phase of critical illness is a progressive acidic state due to unmeasured anions.

Background and objective Stewarts and Fencls methods have recently been proposed to interpret acid–base disorders where traditional theory has proven inadequate. Our objectives were to evaluate: (1) the occurrence of acid–base disturbances in critically ill patients and their trend over the first 3 intensive care unit days, (2) whether Stewarts theory offers advantages over the traditional theory in the diagnosis of acid–base metabolic disturbances and (3) whether variables derived from Stewarts and Fencls methods offer advantages over the traditional method to predict patient mortality. Methods A prospective cohort study in a general intensive care unit. Blood samples were analysed for arterial blood gases, electrolytes and proteins. PaCO2, pH, bicarbonate, base excess, standard base‐excess, sodium, potassium, chloride, phosphorous, calcium, magnesium and lactate were measured. Anion gap, Stewarts and Fencls variables were calculated. Results When using Stewarts method, metabolic acidosis and metabolic alkalosis were found in 92.9% and 93.4% of samples, respectively. Corresponding figures obtained with the traditional method were 15% and 18.7%. In 245 (64.5%) samples, Stewarts method revealed that metabolic acidosis and alkalosis were simultaneously present, whereas the traditional method revealed a normal acid–base status. Strong ion gap increased significantly over the first 3 intensive care unit days. Strong ion gap and lactate were independent predictors of 28‐day mortality. Conclusions Metabolic acidosis by unmeasured anions is a clinically relevant phenomenon, which is correlated with mortality. Progressive metabolic acidosis may be ongoing in the early phase of critical illness despite the absence of acidaemia.

Negative pressure ventilation vs. spontaneous assisted ventilation during rigid bronchoscopy: A controlled randomised trial

Background: Ventilation during interventional rigid bronchoscopy (IRB) under general anaesthesia (jet ventilation, positive pressure ventilation and spontaneous assisted ventilation) may offer some difficulties. This study compares the effectiveness during IRB of intermittent negative pressure ventilation (INPV) and spontaneous assisted ventilation (SAV).

Free radical-induced lipoperoxidation and severe head injury : a clinical study

Ten severely head injured patients (GCS≤8), aged 17–62 years, were studied in order to investigate the role of lipoperoxidation in secondary brain damage. No patients had intracranial mass lesions, shock, hypoxemia, fever or sepsis. Blood samples were taken from the jugular bulb and from the right atrium, and thiobarbituric acid reacting substances (TBARS) were measured in plasma by spectrophotometry. Arterio-jugular venous oxygen differences (AVDO2) were obtained in seven patients, in order to estimate cerebral blood flow. Jugular TBARS (TBARSj) were always elevated (from To, to 2 h after injury) and correlated in a linear fashion with TBARS of right atrium (TBARSv):r=0.74,p<0.001. TBARSj and AVDO2 are closely correlated, in accordance with an exponential function (R=0.45,p<0.001) which describes how any cerebral perfusion derangement determines high levels of TBARSj, confirming lipoperoxidation as a key factor in the final common pathway of secondary posttraumatic brain damage.

Neuromuscular disorders acquired in the ICU

tinely but is sometimes performed after ingestion of high doses, if severe clinical toxicity is expected or when other drugs need to be excluded. Nevertheless, quantitative toxicological analysis in the individual case is of rather small clinical benefit because there appears to be no sure correlation between acute clinical toxicity and drug level, but there are no data from systematic studies. Although in the present case severe toxic symptoms in the early phase of poisoning cannot be ruled out definitely, at the time of admission the patient showed only mild symptoms though his MDMA serum level was 4.3 mg/l, which indeed is rarely reported in the literature [1], and confirmed the foreign anamnestic data of ingested amount of tablets. Even if one considers a mitigating central nervous system-effect of ethanol in the present case, which cannot be substantiated from published data, the fact of a serum concentration of 4.3 mg/l without evident clinical symptoms seems to be uncommon. The case reported here shows that clinical toxicity following aecstasyo overdoses varies considerably among cases and that even extremely high MDMA serum concentrations do not necessarily indicate severe lifethreatening poisoning such as hyperthermic reaction and other complications. This case further supports the idea that severe reactions are idiosyncratic and multifactorial and that drug levels have no clinical use except to confirm which agent is responsible.