Hypercapnic Encephalopathy Research Articles

An Interesting Case of COPD Exacerbation Presenting with Mixed Features of Intracranial Hypertension and Hypercapnic Encephalopathy

Background: Idiopathic intracranial hypertension (IIH or pseudotumor cerebri) has two major morbidities: papilledema with visual loss and disabling headache. Intracranial Venous Hypertension (IVH) is a fundamental mechanism of IIH. Although traditionally considered limiting to the central nervous system, evidence suggests IIH as a systemic disease associated with cardiorespiratory disorders, which has been far less comprehended. Case Report: A 60-year-old female with Chronic Obstructive Pulmonary Disease (COPD) was admitted for dyspnea and developed a coma with a pH of 7.01 and pCO2 of 158 mmHg. She was intubated and had persistent nuchal rigidity, a brief myoclonus episode with a negative electroencephalogram, and negative CT head studies. A Lumbar Puncture (LP) revealed elevated opening pressure (35 cmH2O) with normal Cerebral Spinal Fluid (CSF) studies. Her nuchal rigidity improved after the removal of 40 mL CSF. The ophthalmology examination the next day after her the large volume LP didn’t show visual loss or papilledema. The patient improved clinically and was extubated two days later. Her echocardiogram showed a dilated right ventricle with pulmonary hypertension. The patient was discharged home. Discussion: IIH is different from hypercapnic encephalopathy and characterized by increased intracranial pressure with papilledema, vision loss, and debilitating headache. Hypercapnia-induced increased intracranial venous flow and pulmonary hypertension-caused elevated central venous pressure with consequent outflow resistance lead to IVH. In hypercapnic encephalopathy, the presentation is mostly cognitive changes. In this case, nuchal rigidity with a negative CT head scan triggered the investigation of IIH. Conclusion: A deep understanding of the relationship between COPD and IIH is vital. There is insufficient evidence to recommend routine eye examinations in COPD patients for papilledema and to conduct a pulmonary function test for a newly diagnosed IIH patient. However, we highly suggest a timely ophthalmology exam prior to performing an LP in COPD patients with suspecting IIH to avoid unnecessary procedures and meanwhile improve clinical outcomes.

An Introduction of the Vaporized Therapy with Tea Herb Drink for Relieving Agitation due to Pulmonary Encephalopathy

What methods would you choose apart from increasing sedatives foragitation in an advanced patient with hypercapnic encephalopathy dueto AECOPD? This is a 94-year-old female who suffered from COPD forover 30 years, occurred with an accelerated episode of cough, productivesputum and a dropping down to 86% in SatO₂ due to a cold weather. Adiagnosis of pulmonary encephalopathy (PE) was made on the basis of thesubsequent agitation and delirium, and the sedatives, such as quatiepineand haloperidol, had to be given for her mental excitation respectively, butshe still pulled out indwelling needle herself and refused to any infusiontherapy. As an alternative, a vaporized therapy integrated with tea herbdrinking had to be applied to relieving her agitation, being designedas the vaporization of the inhaled oxygenation by means of high-flowoxygenation device (HFOD), with an ampoule of ambroxol mixed into theinhaler and simultaneous drinking of TCM tea herb for reducing sputum,helping dissolve the mucoid bolts inside her terminal bronchioles whenbeing infected. We thought that a better efficacy would be achieved forhypercapnic encephalopathy due to AECOPD if we concentrate on a goodventilation of small airway through the vaporized therapy.

NON-INVASIVE VENTILATION WITH AVERAGE VOLUME-ASSURED PRESSURE SUPPORT FOR ACUTE HYPERCAPNIC RESPIRATORY FAILURE

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Average volume-assured pressure support (AVAPS) is a comparatively newer modality of non-invasive ventilation that incorporates the properties of both volume and pressure-control ventilation. Though its benefits were well documented in chronic respiratory failure, studies illustrating its usage in acute respiratory failure are still insubstantial. Herein, we aim to showcase the utility of AVAPS in the management of acute on chronic hypercapnic respiratory failure. CASE PRESENTATION: An 80-year-old female with a body mass index (BMI) of 37 kg/m2 and chronic opiate use presented to the Emergency Department (ED) following a two-day history of increasing shortness of breath and confusion. Her medical history was notable for hypersensitivity pneumonitis secondary to bird exposure, former smoker, paroxysmal atrial fibrillation, and recent acute pericarditis for which she is taking aspirin and colchicine. An arterial blood gas (ABG) showed a pH of 7.14, PaCO2 of 124 mmHg (FiO2 28%), PaO2 of 94 mmHg, and bicarbonate of 41 mmol/L. A chest x-ray showed increased bilateral interstitial infiltrates. The patient received IV methylprednisolone and was placed on Spontaneous/Timed mode Bilevel positive airway pressure (BiPAP S/T) with an Inspiratory positive airway pressure (IPAP) of 10 mmHg, Expiratory positive airway pressure (EPAP) of 5 mmHg, and a respiratory rate of 12/min. At these set pressures, her inspired tidal volumes were around 400ml. The patient continued to remain confused (GCS 12/15) and thus, she was switched to average volume-assured pressure support (AVAPS) with a target tidal volume of 500ml. With this modality, she displayed rapid improvement in her symptoms and an ABG drawn eight hours after initiation revealed a pH of 7.34, PaO2 of 66 mmHg, PaO2 of 135 mmHg (FiO2 50%), and bicarbonate of 34 mmol/L. The patient was discharged home on the 5th day after admission. DISCUSSION: AVAPS is an intelligent modality of non-invasive pressure support that gives us the option to set a maximum and a minimum IPAP, in place of one fixed IPAP setting, along with a target tidal volume. The ventilator automatically adjusts the inspiratory pressure within the set range to ensure the delivery of pre-set tidal volume. Patient-ventilator dyssynchronization is prevented and previous studies have reported better patient comfort and satisfaction with AVAPS, thereby, improving patient compliance to the treatment. AVAPS was shown to be superior to BiPAP S/T and associated with a rapid improvement of ABG values and GCS score in patients with acute hypercapnic respiratory failure complicated with hypercapnic encephalopathy (GCS <10/15). CONCLUSIONS: Our case highlights the valuable utility of AVAPS and how, in certain clinical situations, it may be a preferred first-line modality over standard BiPAP S/T for the treatment of acute hypercapnic respiratory failure. REFERENCE #1: Yarrarapu SNS, Saunders H, Sanghavi D. Average Volume-Assured Pressure Support. 2021 Jan 5. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 32809435. DISCLOSURES: No relevant relationships by Pramod Guru, source=Web Response No relevant relationships by Devang Sanghavi, source=Web Response No relevant relationships by Hollie Saunders, source=Web Response No relevant relationships by Siva Naga Yarrarapu, source=Web Response

Average volume-assured pressure support vs conventional bilevel pressure support in pediatric nocturnal hypoventilation: a case series.

Average volume-assured pressure support (AVAPS) is a modality of noninvasive ventilation that provides a targeted tidal volume by automatically adjusting the inspiratory pressure support within a set range. Pediatric studies evaluating the efficacy of AVAPS in treating nocturnal hypoventilation are confined to case reports. The aim of this study was to compare AVAPS to conventional bilevel positive airway pressure (BPAP) support in improving hypercarbia in a cohort of pediatric patients with nocturnal hypoventilation. Retrospective review of patient records at an established tertiary pediatric sleep laboratory over a 6-year period. Ventilatory and sleep study parameters from AVAPS and conventional BPAP titration studies were compared. AVAPS was used only if hypoventilation was not controlled using conventional BPAP. Inspiratory pressures, tidal volumes, and adherence were downloaded on final titrated ventilatory settings. Comparisons were made using paired t test. A total of 19 patients (11 boys, 8 girls; median age 10.5 years, range 1 to 20 years) were identified. Diagnoses included neuromuscular disease (n = 9), obstructive hypoventilation (n = 5), parenchymal lung disease (n = 4), and congenital central hypoventilation syndrome (n = 2). AVAPS demonstrated significant improvement in peak (P = .009) and mean (P = .001). Transcutaneous CO₂ parameters compared to conventional bilevel. Oxygenation on AVAPS showed positive trend but did not reach statistical significance. AVAPS delivered higher tidal volumes (P = .04) using similar pressures. There was no statistically significant difference in obstructive apnea-hypopnea index, respiratory arousal index, sleep efficiency, and adherence between AVAPS and conventional BPAP. AVAPS was an effective alternative to conventional BPAP in improving hypercarbia in our selective cohort of pediatric patients. Prospective, longitudinal studies are needed to evaluate the benefits of AVAPS feature in the pediatric population.

Incidence, Risk Factors, and Prognostic Implications of Acute Kidney Injury in Patients with Acute Exacerbation of COPD.

PurposeLittle is known about the incidence, risk factors, and prognostic implications of acute kidney injury (AKI) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in China. In this study, we investigated the incidence, risk factors, and short-term outcomes of AKI in these patients.Patients and MethodsWe analyzed the records of 1768 patients admitted to Nanjing First Hospital with a principal diagnosis of AECOPD. Of these, 377 patients had AKI.ResultsAKI occurred in 377 patients (21%). Independent risk factors for AKI in patients with AECOPD were advanced age, coronary artery disease, anemia, cancer, chronic kidney disease, hypercapnic encephalopathy, acute respiratory failure, and mechanical ventilation. Patients with AKI had worse prognostic implications and were more likely to require mechanical ventilation (38.7% vs 19.1%, P<0.001); non-invasive mechanical ventilation (38.2% vs 18.9%, P<0.001); invasive mechanical ventilation (18.3% vs 3.1%, P<0.001); intensive care unit (ICU) admission (33.7% vs 12.9%, P<0.001); had a longer ICU stay (9 days vs 8 days, P=0.033) and longer hospitalization (13 days vs 10 days, P<0.001); and higher in-hospital mortality (18.0% vs 2.7%, P<0.001) than those without AKI. Multivariable analysis indicated that compared to patients without AKI, those with stage 1, 2, or 3 AKI had a 1.9-fold, 2.1-fold, or 6.0-fold increased risk of in-hospital death, respectively.ConclusionAKI is common in patients with AECOPD requiring hospitalization. Patients with AKI have worse short-term outcomes. Thus, AKI may be a prognostic predictor of patient survival.

The Clinical Implications of Carbon Dioxide Increased Level in Arterial Blood Related to Severe Exacerbations of Chronic Obstructive Pulmonary Disease

In the evolution of patients with chronic obstructive pulmonary disease (COPD), exacerbations occur, especially, in severe stages, determining aggravated respiratory failure and decreased survival. In order to evaluate the implications of COPD exacerbations in patients with second type of chronic respiratory failure and hypercapnic encephalopathy, a prospective observational study was done among 195 COPD in patients of Targu Mures Clinical County Hospital, Romania. Inclusion criteria consisted in severe exacerbations of COPD, complicated by hypercapnia, defined by an increased level of arterial blood gas carbon dioxide (PaCO2) �45 mmHg, suggestive for the second type of respiratory failure. The increased values of PaCO2 ranged between 45 and 112 mmHg among 95 patients. The prevalence of hypercapnia in COPD patients, admitted in hospital for severe exacerbations, was high (n=91/195; 46.66%). The majority of COPD patients (93.4%) were initially hospitalized in the intensive care unit (ICU) department because of hypercapnic encephalopathy. The mortality rate was higher among patients with endotracheal tube insertion than in patients treated by noninvasive mechanical ventilation. High levels of hypercapnia, conscience disorders and respiratory acidosis may be considered factors of severity in COPD exacerbation.

Bispectral index in hypercapnic encephalopathy associated with COPD exacerbation: a pilot study.

BackgroundHypercapnic encephalopathy is relatively frequent in severe exacerbations of COPD (ECOPDs), with its intensity usually being evaluated through clinical scales. Bispectral index (BIS) is a relatively new technique, based on the analysis of the electroencephalographic signal, which provides a good approximation to the level of consciousness, having already been validated in anesthesia.ObjectiveThe objective of the study was to evaluate the utility of BIS in the assessment of the intensity of hypercapnic encephalopathy in ECOPD patients.Patients and methodsA total of ten ECOPD patients were included, and the level of brain activity was assessed using BIS and different scales: Glasgow Coma Scale, Ramsay Sedation Scale (RSS), and Richmond Agitation–Sedation Scale. The evaluation was performed both in the acute phase and 3 months after discharge.ResultsBIS was recorded for a total of about 600 minutes. During ECOPD, BIS values ranged from 58.8 (95% CI: 48.6–69) for RSS score of 4 to 92.2 (95% CI: 90.1–94.3) for RSS score of 2. A significant correlation was observed between values obtained with BIS and those from the three scales, although the best fit was for RSS, followed by Glasgow and Richmond (r=−0.757, r=0.701, and r=0.615, respectively; P<0.001 for all). In the stable phase after discharge, BIS showed values considered as normal for a wake state (94.6; 95% CI: 91.7–97.9).ConclusionBIS may be useful for the objective early detection and automatic monitoring of the intensity of hypercapnic encephalopathy in ECOPD, facilitating the early detection and follow-up of this condition, which may avoid management problems in these patients.

Early use of noninvasive techniques for clearing respiratory secretions during noninvasive positive-pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease and hypercapnic encephalopathy: A prospective cohort study.

Noninvasive positive-pressure ventilation (NPPV) might be superior to conventional mechanical ventilation (CMV) in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPDs). Inefficient clearance of respiratory secretions provokes NPPV failure in patients with hypercapnic encephalopathy (HE). This study compared CMV and NPPV combined with a noninvasive strategy for clearing secretions in HE and AECOPD patients.The present study is a prospective cohort study of AECOPD and HE patients enrolled between October 2013 and August 2015 in a critical care unit of a major university teaching hospital in China.A total of 74 patients received NPPV and 90 patients received CMV. Inclusion criteria included the following: physician-diagnosed AECOPD, spontaneous airway clearance of excessive secretions, arterial blood gas analysis requiring intensive care, moderate-to-severe dyspnea, and a Kelly–Matthay scale score of 3 to 5. Exclusion criteria included the following: preexisting psychiatric/neurological disorders unrelated to HE, upper gastrointestinal bleeding, upper airway obstruction, acute coronary syndromes, preadmission tracheostomy or endotracheal intubation, and urgent endotracheal intubation for cardiovascular, psychomotor agitation, or severe hemodynamic conditions.Intensive care unit participants were managed by NPPV. Participants received standard treatment consisting of controlled oxygen therapy during NPPV-free periods; antibiotics, intravenous doxofylline, corticosteroids (e.g., salbutamol and ambroxol), and subcutaneous low-molecular-weight heparin; and therapy for comorbidities if necessary. Nasogastric tubes were inserted only in participants who developed gastric distension. No pharmacological sedation was administered.The primary and secondary outcome measures included comparative complication rates, durations of ventilation and hospitalization, number of invasive devices/patient, and in-hospital and 1-year mortality rates.Arterial blood gases and sensorium levels improved significantly within 2 hours in the NPPV group with lower hospital mortality, fewer complications and invasive devices/patient, and superior weaning off mechanical ventilation. Mechanical ventilation duration, hospital stay, or 1-year mortality was similar between groups.NPPV combined with a noninvasive strategy to clear secretions during the first 2 hours may offer advantages over CMV in treating AECOPD patients complicated by HE.

Effect of noninvasive ventilation on hypercapnic encephalopathy syndrome: a Meta-analysis

To evaluate the effect of noninvasive ventilation (NIV) on hypercapnic encephalopathy syndrome (HES) induced by acute exacerbation of chronic obstructive pulmonary disease (AECOPD). An extensive search of related literature from the PubMed, EMBASE, Cochrane library, CNKI and Wanfang databases up to January 2015 was performed. Randomized controlled trials (RCTs) and case control studies regarding comparison of the effect of NIV and conventional mechanical ventilation (CMV) on the HES were collected. Critical appraisal skills program (CASP) was adopted to assess the quality of the studies. Data including mortality, trachea intubation rate, duration of mechanical ventilation and complication rate were collected, and Meta-analysis was performed by RevMan 5.3. Finally, 6 studies were included with 225 subjects, among whom 112 were in NIV group and 113 in CMV group, and the average Kelly-Matthay score was 3. Compared with CMV group, the mortality [20.5% (23/112) vs. 32.7% (37/113), risk ratio (RR) = 0.63, 95% confidential interval (95%CI) = 0.40-0.98, P = 0.04], intubation rate [35.7% (40/112) vs. 100.0% (113/113), RR = 0.38, 95%CI = 0.26-0.55, P < 0.000?01], incidence of ventilation related complications [26.2% (21/80) vs. 50.6% (42/83), RR = 0.52, 95%CI = 0.34-0.79, P = 0.002] in NIV group were significantly decreased, and the duration of mechanical ventilation was significantly shortened [days: 7.1 vs. 16.2, standard mean difference (SMD) = -0.93, 95%CI = -1.39 to -0.46, P < 0.000?1]. NIV could significantly lower the mortality rate, intubation rate, and complications in the treatment of HES induced by AECOPD under close monitoring.

PC-FACS

PC-FACS

Timing of noninvasive ventilation failure: causes, risk factors, and potential remedies

BackgroundIdentifying the predictors of noninvasive ventilation (NIV) failure has attracted significant interest because of the strong link between failure and poor outcomes. However, very little attention has been paid to the timing of the failure. This narrative review focuses on the causes of NIV failure and risk factors and potential remedies for NIV failure, based on the timing factor.ResultsThe possible causes of immediate failure (within minutes to <1 h) are a weak cough reflex, excessive secretions, hypercapnic encephalopathy, intolerance, agitation, and patient-ventilator asynchrony. The major potential interventions include chest physiotherapeutic techniques, early fiberoptic bronchoscopy, changing ventilator settings, and judicious sedation. The risk factors for early failure (within 1 to 48 h) may differ for hypercapnic and hypoxemic respiratory failure. However, most cases of early failure are due to poor arterial blood gas (ABGs) and an inability to promptly correct them, increased severity of illness, and the persistence of a high respiratory rate. Despite a satisfactory initial response, late failure (48 h after NIV) can occur and may be related to sleep disturbance.ConclusionsEvery clinician dealing with NIV should be aware of these risk factors and the predicted parameters of NIV failure that may change during the application of NIV. Close monitoring is required to detect early and late signs of deterioration, thereby preventing unavoidable delays in intubation.

Early fiberoptic bronchoscopy during non-invasive ventilation in patients with decompensated chronic obstructive pulmonary disease due to community-acquired-pneumonia

IntroductionInefficient clearance of copious respiratory secretion is a cause of non-invasive positive pressure ventilation (NPPV) failure, especially in chronic respiratory patients with community-acquired-pneumonia (CAP) and impaired consciousness. We postulated that in such a clinical scenario, when intubation and conventional mechanical ventilation (CMV) are strongly recommended, the suction of secretions with fiberoptic bronchoscopy (FBO) may increase the chance of NPPV success. The objective of this pilot study was, firstly, to verify the safety and effectiveness of early FBO during NPPV and, secondly, to compare the hospital outcomes of this strategy versus a CMV-based strategy in patients with decompensated chronic obstructive pulmonary disease (COPD) due to CAP who are not appropriate candidates for NPPV because of inefficient mucous clearance and hypercapnic encephalopathy (HE).MethodsThis is a 12-month prospective matched case-control study performed in one respiratory semi-intensive care unit (RSICU) with expertise in NPPV and in one intensive care unit (ICU). Fifteen acutely decompensated COPD patients with copious secretion retention and HE due to CAP undergoing NPPV in RSICU, and 15 controls (matched for arterial blood gases, acute physiology and chronic health evaluation score III, Kelly-Matthay scale, pneumonia extension and severity) receiving CMV in the ICU were studied.ResultsTwo hours of NPPV significantly improved arterial blood gases, Kelly and cough efficiency scores without FBO-related complications. NPPV avoided intubation in 12/15 patients (80%). Improvement in arterial blood gases was similar in the two groups, except for a greater PaO2/fraction of inspired oxygen ratio with CMV. The rates of overall and septic complications, and of tracheostomy were lower in the NPPV group (20%, 20%, and 0%) versus the CMV group (80%, 60%, and 40%; P < 0.05). Hospital mortality, duration of hospitalisation and duration of ventilation were similar in the two groups.ConclusionsIn patients with decompensated COPD due to CAP who are candidates for CMV because of HE and inability to clear copious secretions, NPPV with early therapeutic FBO performed by an experienced team is a feasible, safe and effective alternative strategy.

Another step for noninvasive ventilation in chronic obstructive pulmonary disease patients!

The use of noninvasive positive pressure ventilation (NPPV) in chronic obstructive pulmonary disease (COPD) patients who are not eligible for the technique because of their incapability to spontaneously eliminate accumulated secretions associated with hypercapnic encephalopathy is not recommended and is often considered a contraindication. In a case-control study, an experienced team reported the feasibility and safety of the use of NPPV with early fibreoptic bronchoscopy in selected acutely decompensated COPD patients with hypercapnic encephalopathy, and reported the patients' inability to spontaneously clear copious secretions. The reported data suggest that this innovative therapeutic may be considered as a potential alternative to endotracheal intubation.

Effectiveness and safety of noninvasive positive-pressure ventilation for severe hypercapnic encephalopathy due to acute exacerbation of chronic obstructive pulmonary disease: a prospective case-control study

Although severe encephalopathy has been proposed as a possible contraindication to the use of noninvasive positive-pressure ventilation (NPPV), increasing clinical reports showed it was effective in patients with impaired consciousness and even coma secondary to acute respiratory failure, especially hypercapnic acute respiratory failure (HARF). To further evaluate the effectiveness and safety of NPPV for severe hypercapnic encephalopathy, a prospective case-control study was conducted at a university respiratory intensive care unit (RICU) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) during the past 3 years. Forty-three of 68 consecutive AECOPD patients requiring ventilatory support for HARF were divided into 2 groups, which were carefully matched for age, sex, COPD course, tobacco use and previous hospitalization history, according to the severity of encephalopathy, 22 patients with Glasgow coma scale (GCS) < 10 served as group A and 21 with GCS = 10 as group B. Compared with group B, group A had a higher level of baseline arterial partial CO2 pressure ((102 +/- 27) mmHg vs (74 +/- 17) mmHg, P < 0.01), lower levels of GCS (7.5 +/- 1.9 vs 12.2 +/- 1.8, P < 0.01), arterial pH value (7.18 +/- 0.06 vs 7.28 +/- 0.07, P < 0.01) and partial O(2) pressure/fraction of inspired O(2) ratio (168 +/- 39 vs 189 +/- 33, P < 0.05). The NPPV success rate and hospital mortality were 73% (16/22) and 14% (3/22) respectively in group A, which were comparable to those in group B (68% (15/21) and 14% (3/21) respectively, all P > 0.05), but group A needed an average of 7 cm H2O higher of maximal pressure support during NPPV, and 4, 4 and 7 days longer of NPPV time, RICU stay and hospital stay respectively than group B (P < 0.05 or P < 0.01). NPPV therapy failed in 12 patients (6 in each group) because of excessive airway secretions (7 patients), hemodynamic instability (2), worsening of dyspnea and deterioration of gas exchange (2), and gastric content aspiration (1). Selected patients with severe hypercapnic encephalopathy secondary to HARF can be treated as effectively and safely with NPPV as awake patients with HARF due to AECOPD; a trial of NPPV should be instituted to reduce the need of endotracheal intubation in patients with severe hypercapnic encephalopathy who are otherwise good candidates for NPPV due to AECOPD.

Insuffisance respiratoire aiguë isolée révélant une malformation d’Arnold-Chiari

Arnold-Chiari malformation is an occipitocervical malformation where the cerebellar amygdales descend below the occipital foramen. Acute respiratory failure is an exceptional inaugural sign. We report two cases disclosed by alveolar hypoventilation associated with type I Arnold-Chiari malformation. The two patients age 51 and 52 years had an uneventful past history and presented with hypercapnic encephalopathy with acute respiratory failure requiring ventilatory assistance. Respiratory function tests, helicoidal thoracic computed tomographic angiography, electromyogram, cardiac echography, and thyroid and immunological tests were normal. Blood gases and polysomnography were in favor of central hypoventilation without sleep apnea. Magnetic resonance imaging demonstrated type I Arnold-Chiari malformation. The course was complicated by recurrent respiratory failure in both patients. Surgical decompression performed for the first patient provided no improvement. This patient died two months after surgery subsequent to aspiration pneumonia. The second patient was treated with continuous positive pressure noninvasive ventilatory assistance and had a good outcome at 25 months. These two cases illustrate the absence of any neurological sign, acute respiratory failure being the only sign of Arnold-Chiari malformation.

Noninvasive versus conventional ventilation to treat hypercapnic encephalopathy in chronic obstructive pulmonary disease

We recently reported a high success rate using noninvasive positive pressure ventilation (NPPV) to treat COPD exacerbations with hypercapnic encephalopathy. This study compared the hospital outcomes of NPPV vs. conventional mechanical ventilation (CMV) in COPD exacerbations with moderate to severe hypercapnic encephalopathy, defined by a Kelly score of 3 or higher. A 3-year prospective matched case-control study in a respiratory semi-intensive care unit (RSICU) and intensive care unit (ICU). From 103 consecutive patients the study included 20 undergoing NPPV and 20 CMV, matched for age, simplified acute physiology score II, and baseline arterial blood gases. ABG significantly improved in both groups after 2 h. The rate of complications was lower in the NPPV group than in the CMV group due to fewer cases of nosocomial pneumonia and sepsis. In-hospital mortality, 1-year mortality, and tracheostomy rates were similar in the two groups. Fewer patients remained on ventilation after 30 days in NPPV group. The NPPV group showed a shorter duration of ventilation. In COPD exacerbations with moderate to severe hypercapnic encephalopathy, the use of NPPV performed by an experienced team compared to CMV leads to similar short and long-term survivals with a reduced nosocomial infection rate and duration of ventilation.

Encefalitis herpética en Cáceres. Análisis de los últimos cinco años

Herpes simplex encephalitis (HSE) is a rare disease, although it is still the most common serious viral infection of the central nervous system. Little is currently known about its epidemiology and clinical features in our area. This paper presents a retrospective description of the clinical, diagnostic and progressive characteristics of patients diagnosed with HSE in Cáceres General Hospital, and confirmed by means of a polymerase chain reaction (PCR) study for the DNA of the herpes simplex virus over the last 5 years. We found four patients who had been diagnosed with HSE in the last 5 years (3.3 cases/million inhabitants/year; CI at 95% of 2.42-4.18), two males and two females, with an age interval between 58 and 75 years. All the patients had high temperatures and three of them also presented neurological focus. A computerised axial tomography scan of the head performed on admission was interpreted as being normal in all cases, while magnetic resonance imaging of the head carried out in two patients showed lesions compatible with HSE in both cases. Electroencephalographic studies were carried out in two patients and revealed focusing in one of them and severe generalised involvement in the other. Analysis of the cerebrospinal fluid (CSF) disclosed lymphocytic meningitis in four cases, although in one of them the study was normal on admission. In two of the patients, viral meningoencephalitis was suspected from the moment the patient was admitted to hospital. For this reason, early treatment with IV acyclovir was established and the clinical progression was good in both patients, although one of them was left with mild neurological sequelae. The other two cases, who died, had a severe underlying pathology and alternative clinical diagnoses that were reasonable on admission (extensive pneumonia and delirium tremens in one of them, and hypercapnic encephalopathy with severe chronic obstructive pulmonary disease in the other), and the clinical suspicion of HSE and the establishment of treatment were late. The incidence of HSE in our environment is in the upper interval of that reported in the literature. PCR analysis for the herpes simplex virus in CSF seems to have replaced brain biopsy studies as the diagnostic technique. The underlying severe chronic pathology makes it more difficult to diagnose and worsens the prognosis. A multicentre epidemiological study should be conducted to confirm these findings.

Pressure support ventilation via face mask in acute respiratory failure in hypercapnic COPD patients.

To test whether non-invasive ventilation via facial mask could reduce the need for tracheal intubation when mechanical ventilation must be initiated in COPD patients. Open prospective interventional study. General Intensive Care Service of a County Hospital. We have studied 12 COPD patients during 14 episodes of acute exacerbation of chronic respiratory failure who failed to improve with intensive medical therapy and showed impairments in severe respiratory acidosis and/or hypercapnic encephalopathy leading their attending physicians to order mechanical ventilation. In these circumstances, a trial of pressure-support (PS) ventilation (Servo Ventilator 900C) via facial mask Vital Signs Inc.) was performed. The level of pressure support was adjusted to obtain a tidal volume > 400 ml. If the patient deteriorated, tracheal intubation and standard mechanical ventilation were performed. Measurements are presented as means +/- SEM. A pressure-support level of 14 +/- 3 cmH2O was used during a period of 8 +/- 4 h. Low levels of external PEEP were used in 4 patients, while it generated excessive leaks in the others. Significant differences (p < 0.05 ANOVA for repeated measures) in data obtained on admission, when patients deteriorated and after pressure support was administered were only observed in PaCO2 (68 +/- 3 versus 92 +/- 3 versus 67 +/- 3 mmHg), arterial pH (7.27 +/- 0.03 versus 7.19 +/- 0.02 versus 7.31 +/- 0.01). SaO2 (60 +/- 4 versus 86 +/- 3 versus 92 +/- 1%) and respiratory rate (35 +/- 2 versus 32 +/- 2 versus 23 +/- 1 breaths.min-1). Three patients needed intubation and one of them died in the ICU. Non-invasive ventilation (pressure-support) via face mask may reduce the need for tracheal intubation in the severe hypercapnic failure of COPD patients.