Correction Of Hypercapnia Research Articles

Effects of high-flow nasal cannula in patients with mild to moderate hypercapnia: a prospective observational study.

Background Evidence for using high-flow nasal cannula (HFNC) in hypercapnia is still limited. Most of the clinical studies had been conducted retrospectively, and there had been conflicting reports for the effects of HFNC on hypercapnia correction in prospective studies. Therefore, more evidence is needed to understand the effect of the HFNC in hypercapnia.Methods We conducted a multicenter prospective observational study after applying HFNC to 45 hospitalized subjects who had moderate hypercapnia (arterial partial pressure of carbon dioxide [PaCO2], 43–70 mm Hg) without severe respiratory acidosis (pH <7.30). The primary outcome was a change in PaCO2 level in the first 24 hours of HFNC use. The secondary outcomes were changes in other parameters of arterial blood gas analysis, changes in respiration rates, and clinical outcomes.Results There was a significant decrease in PaCO2 in the first hour of HFNC application (-3.80 mm Hg; 95% confidence interval, -6.35 to -1.24; P<0.001). Reduction of PaCO2 was more prominent in subjects who did not have underlying obstructive lung disease. There was a correction in pH, but no significant changes in respiratory rate, bicarbonate, and arterial partial pressure of oxygen/fraction of inspired oxygen ratio. Mechanical ventilation was not required for 93.3% (42/45) of our study population.Conclusions We suggest that HFNC could be a safe alternative for oxygen delivery in hypercapnia patients who do not need immediate mechanical ventilation. With HFNC oxygenation, correction of hypercapnia could be expected, especially in patients who do not have obstructive lung diseases.

Correction of hypercapnia improves cognitive efficiency and attention in a brain-injured patient

Correction of obstructive sleep apnea (OSAS) by non-invasive continuous pressure ventilation (CPAP) allows an improvement of attentional and executive functions, especially post-stroke. On the other hand, in chronic obstructive pulmonary disease, correction of hypercapnia by bilevel positive airway pressure ventilation (BiPAP) improves cognitive impairment. We present a case of a brain-injured patient who remains hypercapnic despite an effective CPAP for the correction of an OSAS. We present a 36-year-old patient with visuo-spatial disorders, dysexecutive syndrome, cerebellar syndrome, swallowing disorders after a rupture of a right vertebral artery aneurysm 2 years before. Oral feeding by adapted texture (mixed), tracheotomy, CPAP for OSAS for several months were needed. We performed cognitive assessments (MoCA: Montreal Cognitive Assessment and BAWL: Attentional Battery William Lennox), pre- (T1) and post- (T2) correction of hypercapnia by night BiPAP, 2 months later. After correction of hypercapnia (T1 PaCO 2 = 7.36 kPa or 55 mmHg then T2 PaCO 2 = 5.86 kPa or 44 mmHg), improvement of: Global cognitive efficiency (MoCA score: + 4/30); Attention (MoCA attention items: +2/6); Simple reaction times (BAWL: –32 ms, from percentile 5 at T1 to percentile 15 at T2); Memory encoding (MoCA 5 words test: + 2/5 points and no false memories anymore). In addition, dysphagia improves by mealtime reduction (50 min versus 1h40) and laryngeal penetration decrease, which allows a withdrawal of the tracheotomy. In this case, the improvement of global cognitive capacities, attention and cognitive processing speed seems to result from the decrease of capnia. The persistence of sequelae of the intracranial aneurysm rupture (specially visuo-spatial and cerebellar) suggests that improvements on cognitive functions stem from the correction of hypercapnia. This case suggests the importance of a normalization of capnia in brain-injured patients with ventilatory disorders to improve the cognitive (global and attentional) capacities and autonomy in daily life (feeding and tracheotomy withdrawal). Larger studies are needed to confirm this.

Mechanical Ventilation for Severe Asthma

Acute exacerbations of asthma can lead to respiratory failure requiring ventilatory assistance. Noninvasive ventilation may prevent the need for endotracheal intubation in selected patients. For patients who are intubated and undergo mechanical ventilation, a strategy that prioritizes avoidance of ventilator-related complications over correction of hypercapnia was first proposed 30 years ago and has become the preferred approach. Excessive pulmonary hyperinflation is a major cause of hypotension and barotrauma. An appreciation of the key determinants of hyperinflation is essential to rational ventilator management. Standard therapy for patients with asthma undergoing mechanical ventilation consists of inhaled bronchodilators, corticosteroids, and drugs used to facilitate controlled hypoventilation. Nonconventional interventions such as heliox, general anesthesia, bronchoscopy, and extracorporeal life support have also been advocated for patients with fulminant asthma but are rarely necessary. Immediate mortality for patients who are mechanically ventilated for acute severe asthma is very low and is often associated with out-of-hospital cardiorespiratory arrest before intubation. However, patients who have been intubated for severe asthma are at increased risk for death from subsequent exacerbations and must be managed accordingly in the outpatient setting.

Efficacy of auto-trilevel positive airway ventilation on patients with both obesity hypoventilation and moderate to severe obstructive sleep apnea syndromes

Introduction To observe the efficacy of auto-trilevel positive airway pressure (Auto-trilevel PAP) ventilation on patients with both obesity hypoventilation syndrome (OHS) and moderate to severe obstructive sleep apnea syndromes (OSAS) by comparison of fixed bilevel positive airway pressure (BiPAP) ventilation. Materials and methods 17 patients with both OHS and moderate to severe OSAS were recruited. Three different positive airway pressure (PAP) modes issued by the ventilators (SOMNOvent auto-S, Weinmann Inc, Germany were used for 8h per night with each mode at each night and two nights' interval without any treatment among different modes. In mode one, the EPAP issued by BiPAP was titrated as the minimal positive pressure for disappearance of snoring. The same inspiratory positive airway pressure (IPAP) titrated by PaCO2 in mode 1 was used in modes 2 and 3 as well. However, the EPAP issued by BiPAP in mode 2 was 3cm H 2 O higher than that in mode 1. In mode 3 with autotrilevel PAP, the beginning of EPAP was set the same as that in mode 1 while the end of EPAP (EEPAP) was automatically adjusted to elevate based on upper airway patency condition. Comparisons were made for parameters before and after treatment as well as among different ventilation modes. The following parameters were compared such as nocturnal apnea hypopnea index (AHI), minimal SpO 2 (miniSpO 2 ), arousal index, sleep efficiency, morning PaCO 2 and daytime ESS. Results Compared with the parameters before ventilation therapies, there was a significant decrease in nocturnal AHI, arousal index, morning PaCO 2 and daytime ESS, but a significant increase in nocturnal miniSpO 2 and sleep efficiency caused by all three modes of ventilation (all P 2 and morning PaCO 2 in mode 2 (all P P 2 ( P 2 . Conclusion Auto-trilevel PAP ventilation is superior over fixed BiPAP ventilaiton for treatment of OHS with coexisting moderate to severe OSAS, since this novel PAP mode can achieve a higher efficacy in simultaneous removal of residual apnea hypopnea events and correction of hypercapnia as well as in achieving a higher sleep quality and lower daytime sleepiness. Acknowledgement Thanks to the Weinmann Inc, Germany which provided our research with Auto-trilevel PAP ventilators for clinical study.

Extracorporeal membrane oxygenation for refractory acute respiratory distress syndrome in severe malaria

BackgroundSevere malaria may be complicated by the acute respiratory distress syndrome (ARDS), which is associated with a high mortality. In the present report, a series of three cases of imported malaria complicated by refractory severe ARDS supported with extracorporeal membrane oxygenation (ECMO) is presented.MethodsOne female and two male adult patients (ages 39 to 53) were included. Two patients had Plasmodium falciparum infection and one patient had Plasmodium vivax and Plasmodium ovale co-infection. Anti-malarial therapy consisted in intravenous quinine (in two patients) and intravenous quinidine (in one patient), plus clindamycin or doxycycline.ResultsDespite lung protective ventilation, a conservative strategy of fluid management, corticosteroids (two patients), prone position (two patients) and inhaled nitric oxide (one patient), refractory severe ARDS supervened (PaO2 to FiO2 ratio 68) and venovenous ECMO was then initiated. In one patient, a bicaval dual-lumen cannula was inserted; in the two other patients, a two-site configuration was used. Two patients survived to hospital-discharge (duration of ECMO support: 8.5 days) and one patient died from nosocomial sepsis and multi-organ failure after 40 days of ECMO support.ConclusionsECMO support allowed adequate oxygenation and correction of hypercapnia under lung protective ventilation, therefore reducing ventilator-induced lung injury. ECMO referral should be considered early in malaria complicated by severe ARDS refractory to conventional treatment.

Diagnostik und Therapie der Rechtsherzinsuffizienz

Right heart failure may be due to increased afterload caused by pulmonary hypertension, increased volume load as in valvular incompetence, myocardial ischemia, and cardiomyopathy. The clinical consequences of those various disease entities are rather homogenous, venous congestion being the key symptom. The diagnosis is based on clinical findings and echocardiography. Right ventricular Tei-index and TAPSE (tricuspid annular plane systolic excursion) are easily obtained measures of right ventricular contractile function. Brain natriuretic peptide is helpful to follow changes in right ventricular dysfunction during therapy. Treatment of right heart failure aims at the correction of the underlying condition, especially if underlying pulmonary disease can be improved. Unifying principles are reduction of excessive pre- and afterload, improved myocardial oxygen delivery and correction of hypercapnia and acidosis, e.g. by ventilatory support. Diuretic therapy must avoid volume depletion resulting in renal failure, whereas volume substitution should be done cautiously. Specific pulmonary vasodilators are indicated only in pulmonary arterial hypertension (PAH) and in inoperable chronic thromboembolic pulmonary hypertension (CTEPH). The standard medical treatment of left heart failure is not generally suitable for right heart dysfunction, except if secondary to left heart disease. In many instances, an interdisciplinary approach to right heart failure is needed, involving the expertise both of the cardiologist and the pulmonologist.

Bilateral Carotid Body Paraganglioma and Central Alveolar Hypoventilation

A 62-year-old woman with a bilateral carotid body paraganglioma presented, 2 years after the removal of the right one, with signs of right-heart failure. Hypoxemia, hypercapnia, polycythemia and pulmonary hypertension with normal ventilatory capacity were found. Central alveolar hypoventilation was diagnosed on the basis of absence of ventilatory response and sensation to provoked hypercapnia, prolonged breath-holding time and correction of hypercapnia by voluntary hyperventilation.

Mechanical controlled hypoventilation in status asthmaticus.

This study reports the results obtained with mechanical ventilation in severe respiratory failure secondary to status asthmaticus. Of the 159 patients with status asthmaticus admitted to the Intensive Respiratory Unit over a 5-yr period, 26 required mechanical ventilation for a total of 34 episodes of acute respiratory acidosis. At the time of intubation, 10 patients were in coma and 5 were in respiratory arrest. Controlled mechanical ventilation was maintained for a mean of 2.5 days. Complications were few and reversible. All patients survived. These favorable results are attributed to a new strategy: mechanical ventilation is used to obtain a correction of hypoxemia with hyperoxic mixtures without attempting to restore an adequate alveolar ventilation. The respirator is adjusted to avoid high airway pressures, which appear to be more dangerous than persistent hypercapnia itself. Correction of hypercapnia is obtained later when bronchial obstruction relief provides better conditions of ventilation-perfusion distribution. So the risks of barotrauma and cardiocirculatory failure, which are frequently reported as fatal complications, appear to be significantly decreased.