Decrease In PaCO2 Research Articles

Nalbuphine and butorphanol reverse opioid-induced respiratory depression but increase arousal in etorphine-immobilized goats (Capra hircus)

ObjectivesTo evaluate and compare the efficacy of two opioid agonist-antagonists, nalbuphine and butorphanol, in reversing etorphine-induced respiratory depression in immobilized goats. Study designProspective, crossover, experimental trial conducted at 1753 m.a.s.l. AnimalsEight adult female Boer goats (Capra hircus). MethodsEight minutes following immobilization with an intramuscular injection of 0.1 mg kg−1 etorphine, goats were given one of nalbuphine (0.8 mg kg−1), butorphanol (0.1 mg kg−1) or sterile water intravenously, in random order in three trials. Respiratory rate (fR), ventilation, tidal volume, oxygen consumption ( V˙O2) and carbon dioxide production ( V˙CO2) were measured continuously. Arterial blood samples to determine PaO2 and PaCO2 were taken 2 minutes before and at 5 minute intervals after etorphine administration for 25 minutes. ResultsBoth nalbuphine and butorphanol increased mean PaO2 from 44 mmHg (5.9 kPa) to 63 mmHg (8.4 kPa) after etorphine administration. Butorphanol, but not nalbuphine, also corrected hypopnea and hypoventilation such that fR increased from 13 ± 4 to 21 ± 7 breaths minute−1 (compared with 16 ± 6 breaths minute−1 following nalbuphine) and ventilation increased from 4.69 ± 3.04 to 6.91 ± 4.42 L minute−1 following butorphanol administration. Despite decreases in PaCO2 following nalbuphine and butorphanol, PaCO2 remained elevated compared with pre-immobilization values [nalbuphine: 34 ± 3 mmHg (4.5 ± 0.3 kPa); butorphanol: 34 ± 2 mmHg (4.5 ± 0.3 kPa)] throughout the immobilization. Both agents also decreased the level of immobilization, and increased V˙O2 and V˙CO2. ConclusionsNalbuphine and butorphanol significantly improved respiratory function in immobilized goats, with butorphanol eliciting a greater positive response than nalbuphine. However, both opioid agonist-antagonists partly reversed etorphine-induced immobilization. Clinical relevanceButorphanol and nalbuphine can be used to improve respiratory parameters in etorphine-immobilized wildlife, with butorphanol being more effective, but unwanted arousal can occur.

Brain injury during venovenous extracorporeal membrane oxygenation.

The frequency of neurological events and their impact on patients receiving venovenous extracorporeal membrane oxygenation (VV-ECMO) are unknown. We therefore study the epidemiology, risk factors, and impact of cerebral complications occurring in VV-ECMO patients. Observational study conducted in a tertiary referral center (2006-2012) on patients developing a neurological complication (ischemic stroke or intracranial bleeding) while on VV-ECMO versus those who did not, and a systematic review on this topic. Among 135 consecutive patients who had received VV-ECMO, 18 (15 assessable) developed cerebral complications on ECMO: cerebral bleeding in 10 (7.5%), ischemic stroke in 3 (2%), or diffuse microbleeds in 2 (2%), occurring after respective medians (IQR) of 3 (1-11), 21 (10-26), and 36 (8-63)days post-ECMO onset. Intracranial bleeding was independently associated with renal failure at intensive care unit admission and rapid PaCO2 decrease at ECMO initiation, but not with age, comorbidities, or hemostasis disorders. Seven (70%) patients with intracranial bleeding and one (33%) with ischemic stroke died versus 40% of patients without neurological event. A systematic review found comparable intracranial bleeding rates (5%). Neurological events occurred frequently in patients on VV-ECMO. Intracranial bleeding, the most frequent, occurred early and was associated with higher mortality. Because it was independently associated with rapid hypercapnia decrease, the latter should be avoided at ECMO onset, but its exact role remains to be determined. These findings may have major implications for the care of patients requiring VV-ECMO.

Acute but not chronic metabolic acidosis potentiates the acetylcholine-induced reduction in blood pressure: an endothelium-dependent effect

Metabolic acidosis has profound effects on vascular tone. This study investigated the in vivo effects of acute metabolic acidosis (AMA) and chronic metabolic acidosis (CMA) on hemodynamic parameters and endothelial function. CMA was induced by ad libitum intake of 1% NH4Cl for 7 days, and AMA was induced by a 3-h infusion of 6 M NH4Cl (1 mL/kg, diluted 1:10). Phenylephrine (Phe) and acetylcholine (Ach) dose-response curves were performed by venous infusion with simultaneous venous and arterial blood pressure monitoring. Plasma nitrite/nitrate (NOx) was measured by chemiluminescence. The CMA group had a blood pH of 7.15±0.03, which was associated with reduced bicarbonate (13.8±0.98 mmol/L) and no change in the partial pressure of arterial carbon dioxide (PaCO2). The AMA group had a pH of 7.20±0.01, which was associated with decreases in bicarbonate (10.8±0.54 mmol/L) and PaCO2 (47.8±2.54 to 23.2±0.74 mmHg) and accompanied by hyperventilation. Phe or ACh infusion did not affect arterial or venous blood pressure in the CMA group. However, the ACh infusion decreased the arterial blood pressure (ΔBP: -28.0±2.35 mm Hg [AMA] to -4.5±2.89 mmHg [control]) in the AMA group. Plasma NOx was normal after CMA but increased after AMA (25.3±0.88 to 31.3±0.54 μM). These results indicate that AMA, but not CMA, potentiated the Ach-induced decrease in blood pressure and led to an increase in plasma NOx, reinforcing the effect of pH imbalance on vascular tone and blood pressure control.

Clinical study of rapid shallow breathing index as the switching point for sequential ventilation for patients with prolonged weaning after thoracolaparotomy

Objective To investigate the influencing factors of successfully switching to sequential ventilation in patients with prolonged weaning due to acute respiratory failure (ARF) after thoracolaparotomy based on the initial rapid shallow breathing index (RSBI) at 60 min after spontaneous breathing trial (SBT) , namely, the f/VT optimal value range of 80 -120 times/(min·L) , thus providing the basis for determining the ideal timing of weaning in clinical practice. Methods A prospective observational study of sequential ventilation [RSBI during the initial SBT (60 min) , 80 -120 breaths/(min·L) ] was carried out in 42 patients on mechanical ventilation (≥48 h) due to post-thoracolaparotomy ARF in the ICUs. According to the duration of the mechanical ventilation, the patients were divided into 2 groups: successfully prolonged weaning group (≥7 days, n =24) and refractory weaning group (<7 days, n =18). The patients with cardiac failure, aged less 18 or over 80, with hepatic dysfunction, or those needing gastrointestinal decompression after esophageal surgery or upper abdomen surgery were excluded. The demographics, APACHEⅡ scores and duration of mechanical ventilation of both groups were recorded, and the respiratory work and oxygen metabolism variables before the switch to sequential ventilation (within 24 hours after admission to ICU) and at the time of switching (24 hours in the ICU after admission) were recorded, respectively: clinical pulmonary infection score (CPIS) , assessment of cough severity, pH, PaO2, PaCO2 and PaO2/FiO2; hemodynamic and microcirculation-related variables: HR, MAP, fluid balance, BNP and Lac; endocrine and metabolism variables: Hb, ALB and random serum cortisol (COR). The clinical features and the changes of the above-mentioned variables before and at the time of switching were compared between both groups. The independent sample t test was used for the single factor comparison and Mann-Whitney U test was applied to the non-normal distributions. The Fisher exact probability test was used for the single factor comparison of ranked data such as categorical variables. Results There were no significant differences in age, gender and severity of disease between two groups ( P >0.05 ) ; the successfully prolonged weaning group had longer duration of invasive mechanical ventilation and ICU stay compared with the refractory weaning group ( P 0.05) ; while in the successfully delayed weaning group, there were significant decrease in CPIS, PaCO2, HR, MAP, BNP, fluid balance and Lac ( P <0.05) , and cough severity, pH, ALB and COR showed an upward trend ( P <0.05). Conclusions The key of successful sequential ventilation is within the values of RSBI ranging from 80 to 120 times/(min·L) during the initial SBT (60 min) selected as the switching point in patients with prolonged weaning after thoracolaparotomy. The major influencing factors for determining the ideal timing of switching include the matching status between respiratory endurance and respiratory work, the balance between myocardial strength and both cardiac preload and afterload, the severe disease associated with adrenal insufficiency, and malnutrition. Key words: Post-thoracolaparotomy; Prolonged weaning; Sequential ventilation; Switching point; Rapid shallow breathing index

EFFECTS OF EXPERIMENTAL HUMAN ENDOTOXEMIA ON DIAPHRAGM FUNCTION.

Systemic inflammation is a well-known risk factor for respiratory muscle weakness. Studies using animal models of inflammation have shown that endotoxin administration induces diaphragm dysfunction. However, the effects of in vivo endotoxin administration on diaphragm function in humans have not been studied. Our aim was to evaluate diaphragm function in a model of systemic inflammation in healthy subjects. Two groups of 12 male volunteers received an intravenous bolus of 2 ng/kg of Escherichia coli lipopolysaccharide (LPS) and were monitored until 8 h after LPS administration. In the first group, the twitch transdiaphragmatic pressure (Pditw) and compound muscle action potential of the diaphragm (CMAPdi) were measured. In addition, plasma levels of cytokines, heart rate, and arterial blood pressure were measured. In the second group, catecholamines as well as respiratory rate and blood gas values were measured. Diaphragm ultrasonography was performed in four subjects with severe shivering. Lipopolysaccharide administration resulted in flulike symptoms, hemodynamic alterations, and increased plasma levels of cytokines. The Pditw increased after LPS administration from 31.2 ± 2.0 cmH2O (baseline) to 38.8 ± 2.0 cmH2O (t = 1 h) and 35.4 ± 2.0 cmH2O (t = 1.5 h). There was no correlation between cytokine plasma levels and the Pditw. We found a trend toward a gradual decrease in the CMAPdi from 0.78 ± 0.07 mV (baseline) to 0.58 ± 0.05 mV (t = 2 h). Respiratory rate increased after LPS administration from 16.8 ± 0.5 breaths/min (baseline) to 20.3 ± 0.6 breaths/min (t = 4 h), with a resulting decrease in PaCO2 of 0.5 ± 0.1 kPa. Plasma levels of epinephrine peaked at t = 1.5 h, with an increase of 1.3 ± 0.3 nmol/L from baseline. Rapid diaphragm contractions consistent with shivering were observed. This study shows that, in contrast to diaphragm dysfunction observed in animal models of inflammation, in vivo diaphragm contractility is augmented in the early phase after low-dose endotoxin administration in humans.

Influence of effective noninvasive positive pressure ventilation on inflammatory and cardiovascular biomarkers in stable hypercapnic COPD patients

BackgroundNoninvasive positive pressure ventilation (NPPV) using effective pressure levels to reduce chronic hypercapnia improves survival in stable hypercapnic COPD. However, the underlying mechanisms remain unclear. This study investigated the influence of effective NPPV on a panel of cytokines and established cardiovascular biomarkers. MethodsPeripheral blood samples were drawn before and three months after the initiation of NPPV and analyzed by flow cytometric bead array and ELISA. ResultsTwenty COPD patients (forced expiratory volume in 1 s 31 ± 17% predicted) were included. NPPV (inspiratory positive airway pressure 23 ± 4 mbar; breathing frequency 17 ± 2/min) significantly improved arterial carbon dioxide pressure (PaCO2), both during daytime spontaneous breathing (p = 0.005) and nighttime ventilation (p < 0.001). Serum interleukin (IL)-10 levels were slightly reduced (p = 0.016), whereas IL-1 (p = 0.073) and IL-12 (p = 0.089) showed only a tendency towards change over time. Pro-brain natriuretic peptide (proBNP) significantly decreased by a mean of 578 ± 1332 ng/L after three months' NPPV (p = 0.017 vs baseline). No other significant changes in cardiovascular biomarkers occurred. The decrease in PaCO2 during daytime spontaneous breathing was positively correlated with the reduction in proBNP (correlation coefficient 0.613; p = 0.0197). ConclusionEffective NPPV impacts on systemic inflammation in COPD patients. Furthermore, reductions in PaCO2 during NPPV were associated with decreases in proBNP levels. Future studies are needed to clarify these findings in a larger cohort of COPD patients. Clinical trial registrationDRKS00007644 (German Clinical Trials Register; https://drks-neu.uniklinik-freiburg.de/drks_web/navigate.do?navigationId=resultsExt).

Changes in arterial blood gases after use of high-flow nasal cannula therapy in the ED

IntroductionA high-flow nasal cannula (HFNC) has been used to treat patients with dyspnea. We identified changes in arterial blood gas (ABG) of patients visiting the emergency department (ED) with hypercapnic and nonhypercapnic respiratory failure after use of an HFNC. MethodsThis study was a retrospective chart review of patients with respiratory failure who visited the hospital and used an HFNC in the ED. The study period was July 1, 2011, to December 31, 2013. Patients with Paco2 greater than 45 mm Hg before the HFNC ABG analyses were included in the hypercapnia group; others comprised the nonhypercapnia group. Primary outcomes were the changes in ABG before and after use of an HFNC in the hypercapnia and nonhypercapnia groups. Progression to noninvasive or invasive ventilation and mortality rates were also assessed. ResultsA total of 173 patients were included after exclusion of 92 according to exclusion criteria. Eighty-one patients (hypercapnia group, 46, and nonhypercapnia group, 35) were included. Paco2 significantly decreased among all patients after use of HFNC (from 54.7 ± 26.4 mm Hg to 51.3 ± 25.8 mm Hg; P = .02), but the reduction was significant only in the hypercapnia group (from 73.2 ± 20.0 to 67.2 ± 23.4; P = .02). Progression to noninvasive or invasive ventilation and mortality rates were similar between the groups. ConclusionsUse of an HFNC in patients with hypercapnia could show a significant trend of decrease in Paco2. Progression to noninvasive or invasive ventilation and mortality rates were similar in patients with and without hypercapnia.

PS-244 Acetazolamide Treatment For Metabolic Alkalosis In A Paediatric Intensive Care Unit

<h3>Study</h3> <h3>Objective</h3> To evaluate the efficacy of enteral acetazolamide treatment for hypochloraemic metabolic alkalosis in critically ill children. <h3>Methods</h3> We designed an observational retrospective study that included critically ill children admitted to the PICU from January 2010 to December 2013 and treated with acetazolamide for at least 48 h for metabolic alkalosis. We recorded demographic data, dose and type of diuretic treatment, use of mechanical ventilation and acid-base and biochemical data. Acetazolamide was administered enterally and both dose and adverse effects were collected. <h3>Results</h3> A total of 120 episodes of treatment (86 post-cardiac surgery, 17 cardiac decompensations and 17 patients with respiratory disease) in 93 patients (median age 6 months) were analysed. 85% received a continuous IV furosemide infusion and 14.2% intermittent bolus administration of furosemide. Furosemide doses of patients with respiratory disease were lower (p &lt; 0,001) than in patients with other pathologies. After 48 h of treatment a significant decline in bicarbonate levels (from 35,3 ± 4,7 to 31,1 ± 3,9 mmol/L, p &lt; 0,001), pH (from 7,45 ± 0,05 to 7,41 ± 0,06, p &lt; 0,001), and PCO2 (from 52.9 ± 10 to 51,2 ± 10 mmHg, p = 0,002) were found, whereas anion GAP increased (from 6,8 ± 9,8 to 8,7 ± 3,8, p = 0,001). Mechanical ventilation was in use in 102 patients, (31,6% were extubated during acetazolamide treatment). Average Acetazolamide dose was 8,46 mg/Kg/day. None of the patients suffered from serious side-effects attributable to Acetazolamide. <h3>Conclusions</h3> Acetazolamide treatment improved metabolic alkalosis secondary to diuretic treatment in critically ill children, contributing to a decrease in PaCO2. Enteral administration was effective and well tolerated without serious adverse effects.

Age, aerobic fitness, and cerebral perfusion during exercise: role of carbon dioxide.

Middle cerebral artery mean velocity (MCAvmean) is attenuated with increasing age both at rest and during exercise. The aim of this study was to determine the influence of the age-dependent reduction in arterial Pco2 (PaCO2) and physical fitness herein. We administered supplemental CO2 (CO2 trial) or no additional gas (control trial) to the inspired air in a blinded and randomized manner, and assessed middle cerebral artery mean flow velocity during graded exercise in 1) 21 young [Y; age 24 ± 3 yr (±SD)] volunteers of whom 11 were trained (YT) and 10 considered untrained (YUT), and 2) 17 old (O; 66 ± 4 yr) volunteers of whom 8 and 9 were considered trained (OT) and untrained (OUT), respectively. A resting hypercapnic reactivity test was also performed. MCAvmean and PaCO2 were lower in O [44.9 ± 3.1 cm/s and 30 ± 1 mmHg (±SE)] compared with Y (59.3 ± 2.3 cm/s and 34 ± 1 mmHg, P < 0.01) at rest, independent of aerobic fitness level. The age-related decreases in MCAvmean and PaCO2 persisted during exercise. Supplemental CO2 reduced the age-associated decline in MCAvmean by 50%, suggesting that PaCO2 is a major component in the decline. On the other hand, relative hypercapnic reactivity was neither influenced by age (P = 0.46) nor aerobic fitness (P = 0.36). Although supplemental CO2 attenuated exercise-induced reduction in cerebral oxygenation (near-infrared spectroscopy), this did not influence exercise performance. In conclusion, PaCO2 contributes to the age-associated decline in MCAvmean at rest and during exercise; however exercise capacity did not diminish this age effect.

Ambulatory adaptation to noninvasive ventilation in restrictive pulmonary disease: A randomized trial with cost assessment

Home mechanical ventilation is usually initiated in hospital. However, cost-effectiveness of inpatient set up has never been compared to outpatient adaptation in a randomized design. A Prospective, multicenter, non-inferiority trial was conducted comparing the effectiveness of adaptation to noninvasive mechanical ventilation (NIMV) performed in the ambulatory or hospital setting in patients with chronic respiratory failure secondary to restrictive thoracic disease, obesity-hypoventilation syndrome or neuromuscular disease. The study included 53 candidates for NIMV, randomized to ambulatory adaptation (AA) (n=27) or hospital adaptation (HA) (n=26). The patients' characteristics were recorded before establishing ventilation and at 1 and 6 months after. The main outcome variable was PaCO2 decrease at 6 months following initiation of NIMV. The direct costs of the two interventions were compared. Before starting NIMV, PaCO2 was 50.4±6.8mmHg in the AA group and 50.3±5.7mmHg in the HA group. At 6 months of NIMV use, a significant improvement in PaCO2 relative to baseline was found in both groups: mean (95% CI) PaCO2 decrease was 4.9 (2.3; 7.4) mmHg in AA and 3.3 (1.4; 5.1) mmHg in HA. The direct calculated cost was 1500 euros per patient in AA and 2692 euros per patient in HA. Adaptation to NIMV in the ambulatory setting is not inferior to hospital adaptation in terms of therapeutic equivalence in stable patients with chronic respiratory failure secondary to restrictive thoracic disease, obesity-hypoventilation syndrome or neuromuscular disease. Outpatient adaptation may represent a cost saving for the healthcare system. Identifier number NCT00698958 at www.clinicaltrials.gov.

Population Pharmacodynamic Modeling and Simulation of the Respiratory Effect of Acetazolamide in Decompensated COPD Patients

BackgroundChronic obstructive pulmonary disease (COPD) patients may develop metabolic alkalosis during weaning from mechanical ventilation. Acetazolamide is one of the treatments used to reverse metabolic alkalosis.Methods619 time-respiratory (minute ventilation, tidal volume and respiratory rate) and 207 time-PaCO2 observations were obtained from 68 invasively ventilated COPD patients. We modeled respiratory responses to acetazolamide in mechanically ventilated COPD patients and then simulated the effect of increased amounts of the drug.ResultsThe effect of acetazolamide on minute ventilation and PaCO2 levels was analyzed using a nonlinear mixed effect model. The effect of different ventilatory modes was assessed on the model. Only slightly increased minute ventilation without decreased PaCO2 levels were observed in response to 250 to 500 mg of acetazolamide administered twice daily. Simulations indicated that higher acetazolamide dosage (>1000 mg daily) was required to significantly increase minute ventilation (P<.001 vs pre-acetazolamide administration). Based on our model, 1000 mg per day of acetazolamide would increase minute ventilation by >0.75 L min−1 in 60% of the population. The model also predicts that 45% of patients would have a decrease of PaCO2>5 mmHg with doses of 1000 mg per day.ConclusionsSimulations suggest that COPD patients might benefit from the respiratory stimulant effect after the administration of higher doses of acetazolamide.

Cerebral hemodynamic and oxygenation changes induced by inner and heard speech: a study combining functional near-infrared spectroscopy and capnography

The aim of this study was to investigate the effects of inner and heard speech on cerebral hemodynamics and oxygenation in the anterior prefrontal cortex (PFC) using functional near-infrared spectroscopy and to test whether potential effects were caused by alterations in the arterial carbon dioxide pressure (PaCO2). Twenty-nine healthy adult volunteers performed six different tasks of inner and heard speech according to a randomized crossover design. During the tasks, we generally found a decrease in PaCO2 (only for inner speech), tissue oxygen saturation (StO2), oxyhemoglobin ([O2Hb]), total hemoglobin ([tHb]) concentration and an increase in deoxyhemoglobin concentration ([HHb]). Furthermore, we found significant relations between changes in [O2Hb], [HHb], [tHb], or StO2 and the participants' age, the baseline PETCO2, or certain speech tasks. We conclude that changes in breathing during the tasks led to lower PaCO2 (hypocapnia) for inner speech. During heard speech, no significant changes in PaCO2 occurred, but the decreases in StO2, [O2Hb], and [tHb] suggest that changes in PaCO2 were also involved here. Different verse types (hexameter and alliteration) led to different changes in [tHb], implying different brain activations. In conclusion, StO2, [O2Hb], [HHb], and [tHb] are affected by interplay of both PaCO2 reactivity and functional brain activity.

Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

BACKGROUNDOne of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model.METHODSJuvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer’s lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control.RESULTSFive swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state.CONCLUSIONSA cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

Salvia miltiorrhiza injection on pulmonary heart disease: a systematic review and meta-analysis.

Cor pulmonale (pulmonary heart disease) is a chronic progressive complicated disease for which treatment needs to be sustained all the time, creating a great financial burden on individuals and society. In order to improve the life quality of cor pulmonale patients and decrease the dosage and quantity of the routine treatment, in China, TCM is often administered to patients with cor pulmonale. The results of many clinical trials have indicated that Salvia miltiorrhiza and complex Salvia miltiorrhiza injection may be an alternative medicine for cor pulmonale. With the purpose to prove whether Salvia miltiorrhiza and complex Salvia miltiorrhiza benefit the cor pulmonale patients, respectively, we carried out a systematic review to evaluate the efficacy and safety of Salvia miltiorrhiza and complex Salvia miltiorrhiza injection in cor pulmonale patients. Overall, 2,715 patients were identified from 35 randomized controlled trials. The meta-analysis used I(2) test for heterogeneity and chose random or fixed model according to heterogeneity of included studies. Clinical outcomes were evaluated by total effectiveness rate, partial pressure of oxygen ( PaO 2) and carbon dioxide ( PaCO 2), hemorheology, mPAP and adverse effects. Compared with routine medicine treatment alone, routine medicine treatment plus Salvia miltiorrhiza or complex Salvia miltiorrhiza injection showed better outcomes: A significantly higher clinical effectiveness rate ratio (p < 0.001), increase in PaO 2 (p < 0.001) and decrease in PaCO 2 (p < 0.001), improvement in hemorheology (p < 0.001), and alleviation in mPAP (p < 0.05). There is no obvious adverse effect reported. In summary, there are some evidences suggesting that Salvia miltiorrhiza or complex Salvia miltiorrhiza injection are active in cor pulmonale, however, the results were limited by the methodological flaws of the included studies. Long-term and high quality clinical trials are needed to provide more conclusive evidence for the future use of Salvia miltiorrhiza injection.

Severe hypernatremia and hyperchloremia in an elderly patient with IgG-kappa type

Severe hypernatremia and hyperchloremia in an elderly patient with IgG-kappa type Kenrick BerendSt Elisabeth Hospital, Willemstad, Cura&ccedil;aoImashuku et al1 describe a 77-year-old male patient with multiple myeloma who was admitted to the hospital after suffering a pelvic bone fracture due to a road traffic accident. Several days after admission the arterial blood gas showed a pH of 7.481; arterial carbon dioxide tension (PaCO2) of 28.2 mmHg; arterial oxygen tension (PaO2) of 84.0 mmHg; HCO3- of 20.8 mmol/L (normal; 23&ndash;31 mmol/L); and an anion gap of 8.9 mmol/L (normal;12 mmol/L). These data, as the authors concluded, were suggestive of metabolic acidosis. First, this is not true because a high pH and low PaCO2 confirm a respiratory alkalosis. Since the test was conducted days later we may expect a chronic respiratory alkalosis to be present, perhaps because of pain or a secondary pulmonary problem, as may be expected with a relatively low PaO2. In chronic respiratory alkalosis one would expect the HCO3- to decrease about 4 mmol/L with every 10 mmHg decrease of PaCO2.2 If the initial HCO3- had been about 25 mmol/L, the expected PaCO2 would be about 20.28 mmol/L, almost identical with the patient&rsquo;s HCO3-.View original paper by Imashuku and colleagues.

Heliox for mechanically ventilated newborns with bronchopulmonary dysplasia

ObjectiveWe assessed the safety and studied the influence of short-term helium–oxygen (heliox) mechanical ventilation (MV) on respiratory function, gas exchange and oxygenation in infants with bronchopulmonary dysplasia (BPD) or at...

Pulmonary embolism in patients with chronic obstructive pulmonary disease and exacerbations of unknown origin

Background: Despite important advances in the diagnosis and treatment of acute pulmonary embolism (APE), diagnosis of pulmonary embolism (PE) is difficult in patients with chronic obstructive pulmonary disease (COPD) and exacerbation. Objective: We evaluated PE in patients with chronic obstructive pulmonary disease and exacerbations of unknown origin. Methods: Two-hundred and eight patients with COPD and severe exacerbations were studied. All patients had CT pulmonary angiography (CTPA) and lower limb ultrasonography. Arterial blood gas measurements, D-dimers and endothelin-1 (ET-1) levels were recorded. Results: The frequency of PE was 33%. The following were more common in the PE group (χ 2 = 4.32–6.79, mean p < 0.05): immobilization ≥ 7 days; a ≥ 1 cm difference in edema of the lower limbs; deep venous thrombosis; syncope; S1Q3T3 syndrome; and a decrease in PaCO 2 ≥ 5 mm Hg. Plasma D-dimers and ET-1 levels were significantly higher in the PE group. Risk factors identified from logistic regression analysis were immobilization ≥ 7 days, ≥ 1 cm difference in lower limb edema, and deep venous thrombosis. Conclusions: Overall, 33% of 208 patients had a PE, and the risk was greater in those who had been immobilized, those who had a ≥ 1 cm difference in edema of the lower limbs, and those who had a deep venous thrombosis.

Magnitude of Arterial Carbon Dioxide Change at Initiation of Extracorporeal Membrane Oxygenation Support Is Associated with Survival

Many patient factors have been associated with mortality from extracorporeal membrane oxygenation (ECMO) therapy. Pre-ECMO patient pH and arterial carbon dioxide (paCO2) have been associated with poor outcome and can be significantly altered by ECMO initiation. We hypothesized that the magnitude of change in paCO2and pH with ECMO initiation could be associated with survival. We designed a retrospective observational study from a single tertiary care center and included all pediatric patients (age younger than 18 years) undergoing ECMO between 2002 and 2010. Electronic records were queried for demographics and clinical characteristics, including the arterial blood gas (ABG) pre- and post-ECMO initiation. Bivariate analysis compared ECMO course characteristics by outcome (survivor vs. nonsurvivor). Multivariable logistic regression was performed on factors associated with the outcome in the bivariate analysis at the significance level ofp&lt; .1. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were reported. We identified 201 patients with a median age of 10 days (range, 1 day to 16 years). Indications for ECMO were: respiratory failure (51%), cardiac failure (23%), extracorporeal cardiopulmonary resuscitation (21%), and sepsis (5%). Mortality, defined by death before discharge, was 37% (74 of 201). ABG data pre- and post-ECMO initiations were available in 84% (169 of 201). Age, pH, paCO2, indication, and intracranial hemorrhage were significantly associated with mortality (p&lt; .05). After adjusting for potential confounders (age, use of epinephrine, volume of fluid administered, year of ECMO, ECMO indication, and duration of ECMO) by multivariable logistic regression, the magnitude of paCO2change (≥25 mmHg) was associated with mortality (adjusted OR, 2.21; 95% CI, 1.06–4.63;p= .036). The decrease in paCO2with ECMO initiation was associated with mortality. Although this change in paCO2is multifactorial, it represents a modifiable element of clinical management involving pre-ECMO ventilation, ECMO circuit priming, CO2administration/removal, and may represent a future therapeutic target that could improve survival in pediatric ECMO.

Effect of Percutaneous Tracheostomy on Gas Exchange in Hypoxemic and Non-hypoxemic Mechanically Ventilated Patients

The influence of percutaneous tracheostomy on ventilator-dependence and clinical outcomes has been investigated in a number of studies. However, except for the variations during the procedure, the impact of tracheostomy on gas exchange has been scarcely explored. We investigated the effect of tracheostomy on respiratory function in a cohort of ICU patients. In this retrospective study, clinical records of 107 patients from a general ICU and neurosurgical ICU who underwent percutaneous tracheostomy were reviewed to compare ventilator setting, gas exchange, and hemodynamic parameters on the day before and on the day after the procedure. Further, a pre-established subgroup analysis on hypoxemic patients (Pao2/Fio2 < 300 mm Hg) was performed. Among all patients analyzed, a marginal decrease in Paco2 (43 ± 9 mm Hg vs 42 ± 7 mm Hg, before vs after P = .004) and an increase in pH (7.43 ± 0.04 vs 7.44 ± 0.03, before vs after P = .03) were observed after tracheostomy. In the subgroup of hypoxemic patients (n = 38), after the tracheostomy an increase in Pao2/Fio2 (222 ± 60 mm Hg vs 256 ± 84 mm Hg, before vs after P = .001) and a decrease in Paco2 (46 ± 11 mm Hg vs 43 ± 9 mm Hg, before vs after P = .001) were found. Percutaneous tracheostomy did not worsen gas exchange in a cohort of ICU patients. In hypoxemic patients, tracheostomy appeared to improve oxygenation and ventilation.

Cerebral tissue oxygen saturation during therapeutic hypothermia in post-cardiac arrest patients

Aim of the studyThis observational study was performed to assess the cerebral tissue oxygen saturation during and after therapeutic hypothermia in comatose patients after out-of-hospital cardiac arrest. MethodsWe performed a prospective observational study on the cerebral tissue oxygen saturation (SctO2) in post-cardiac arrest patients treated with therapeutic hypothermia (TH) between March 2011 and April 2012. SctO2 (measured by near-infrared spectroscopy) was non-invasively and continuously measured in 28 post-cardiac arrest patients during hypothermia and active rewarming. ResultsAt the start of mechanically induced TH, SctO2 was 68% (65–72) and PaCO2 was 47.2mmHg (36.9–51.4). SctO2 and PaCO2 significantly decreased to 59% (57–64; p=0.006) and 36.6mmHg (33.9–44.7; p=0.002), respectively, within the first 3h of mechanically induced TH. Cerebral tissue oxygen saturation was significantly lower in non-survivors (n=10) compared with survivors (n=18) at 3h after induction of hypothermia (p=0.02) while the decrease in PaCO2 was similar in both groups. During TH maintenance, SctO2 gradually returned to baseline values (69% (63–72)) at 24h, with no differences between survivors and non-survivors (p=0.65). Carbon dioxide remained within the range of mild hypocapnia (32–38mmHg) throughout the hypothermic period. During rewarming, SctO2 further increased to 71% (67–78). ConclusionsInduction of TH in comatose post-CA patients changes the balance between oxygen delivery and supply. The decrease in SctO2 was less pronounced in patients surviving to hospital discharge.