BACKGROUNDPropofol is increasingly used during partial support mechanical ventilation such as pressure support ventilation (PSV) in postoperative patients. However, breathing pattern, respiratory drive, and patient-ventilator synchrony are affected by the sedative used and the sedation depth. The present study aimed to evaluate the physiologic effects of varying depths of propofol sedation on respiratory drive and patient-ventilator synchrony during PSV in postoperative patients.

METHODSEight postoperative patients receiving PSV for <24 h were enrolled. Propofol was administered to achieve and maintain a Ramsay score of 4, and the inspiratory pressure support was titrated to obtain a tidal volume (VT) of 6-8 ml/kg. Then, the propofol dose was reduced to achieve and maintain a Ramsay score of 3 and then 2. At each Ramsay level, the patient underwent 30-min trials of PSV. We measured the electrical activity of the diaphragm, flow, airway pressure, neuro-ventilatory efficiency (NVE), and patient-ventilator synchrony.

RESULTSIncreasing the depth of sedation reduced the peak and mean electrical activity of the diaphragm, which suggested a decrease in respiratory drive, while VT remained unchanged. The NVE increased with an increase in the depth of sedation. Minute ventilation and inspiratory duty cycle decreased with an increase in the depth of sedation, but this only achieved statistical significance between Ramsay 2 and both Ramsay 4 and 3 (P < 0.05). The ineffective triggering index increased with increasing sedation depth (9.5 ± 4.0%, 6.7 ± 2.0%, and 4.2 ± 2.1% for Ramsay 4, 3, and 2, respectively) and achieved statistical significance between each pair of depth of sedation (P < 0.05). The depth of sedation did not affect gas exchange.

CONCLUSIONSPropofol inhibits respiratory drive and deteriorates patient-ventilator synchrony to the extent that varies with the depth of sedation. Propofol has less effect on breathing pattern and has no effect on VT and gas exchange in postoperative patients with PSV.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Blood Pressure ; drug effects ; physiology ; Female ; Hemodynamics ; drug effects ; physiology ; Humans ; Intensive Care Units ; Male ; Middle Aged ; Positive-Pressure Respiration ; methods ; Propofol ; therapeutic use ; Prospective Studies ; Respiration, Artificial ; methods ; Tidal Volume ; drug effects ; physiology ; Young Adult

OBJECTIVETo investigate the effects of inhaled short-acting bronchodilators on diaphragm function and neural respiratory drive in patients with chronic obstructive pulmonary disease (COPD) during maximal isocapnic ventilation (MIV).

METHODSForty-seven patient with moderate to severe COPD were randomized into 4 groups: placebo group (n=12), salbutamol group (n=13), ipratropium group (n=10), and combined group (salbutamol and ipratropium, n=12). Each subject received an initial MIV for 3 min at baseline and inhaled placebo (400 µg), salbutamol (400 µg), ipratropium (80 µg), or both salbutamol and ipratropium, followed 30 min later by another 3 min of MIV. The parameters of diaphragm function and neural respiratory drive were monitored continuously and calculated during MIV.

RESULTSDuring the initial MIV, all the patients experienced a linear increase in root mean square (RMS) of diaphragm electromyogram with a gradual decrease in transdiaphragmatic pressure (Pdi), minute ventilation (VE), and VE/RMS, and these parameters all improved significantly after inhalation of the bronchodilators. Compared with the placebo group at the same time point, the 3 bronchodilator-treated groups showed significantly decreased RMS and Borg score and increased Pdi, VE and VE/RMS; VE/RMS was the highest in the combined treatment group (P<0.05). The Delta Borg was significantly correlated with Delta Pdi, Delta VE, Delta RMS, and Delta VE/RMS (P<0.05).

CONCLUSIONSIn COPD patients, inhaled short-acting bronchodilators can alleviate diaphragm fatigue during MIV, increase lung ventilation, reduce neural respiratory drive, and improve neuro-ventilatory coupling to relieve dyspnoea, and the combination of β-2 agonists and anti-muscarinic antagonists produces a stronger efficacy.

Administration, Inhalation ; Albuterol ; therapeutic use ; Bronchodilator Agents ; therapeutic use ; Diaphragm ; drug effects ; Humans ; Ipratropium ; therapeutic use ; Pulmonary Disease, Chronic Obstructive ; drug therapy ; Respiration

PURPOSETo evaluate midazolam sequential with dexmedetomidine for agitated patients undergoing weaning to implement light sedation in ICU.

METHODSThis randomized, prospective study was conducted in Tianjin Third Central Hospital, China. Using a sealed-envelope method, the patients were randomly divided into 2 groups (40 patients per group). Each patient of group A received an initial loading dose of midazolam at 0.3-3mg/kg·h 24 h before extubation, followed by an infusion of dexmedetomidine at a rate of 0.2-1 μg/kg·h until extubation. Each patient of group B received midazolam at a dose of 0.3-3 mg/kg·h until extubation. The dose of sedation was regulated according to RASS sedative scores maintaining in the range of -2-1. All patients were continuously monitored for 60 min after extubation. During the course, heart rate (HR), mean artery pressure (MAP), extubation time, adverse reactions, ICU stay, and hospital stay were observed and recorded continuously at the following time points: 24 h before extubation (T1), 12 h before extubation (T2), extubation (T3), 30 min after extubation (T4), 60 min after extubation (T5).

RESULTSBoth groups reached the goal of sedation needed for ICU patients. Dexmedetomidine was associated with a significant increase in extubation quality compared with midazolam, reflected in the prevalence of delirium after extubation (20% (8/40) vs 45% (18/40)), respectively (p= 0.017). There were no clinically significant decreases in HR and MAP after infusing dexmedetomidine or midazolam. In the group A, HR was not significantly increased after extubation; however, in the group B, HR was significantly increased compared with the preextubation values (p < 0.05). HR was significantly higher in the group B compared with the group A at 30 and 60 min after extubation (both, p <0.05). Compared with preextubation values, MAP was significantly increased at extubation in the group B (p < 0.05) and MAP was significantly higher at T3, T4, T5 in the group B than group A (p < 0.05). There was a significant difference in extubation time ((3.0 ± 1.5) d vs (4.3 ± 2.2) d, p < 0.05), ICU stay ((5.4 ± 2.1) d vs (8.0 ± 1.4) d, p < 0.05), hospital stay ((10.1 ± 3.0) d vs (15.3 ± 2.6) d, p <0.05) between group A and B.

CONCLUSIONMidazolam sequential with dexmedetomidine can reach the goal of sedation for ICU agitated patients, meanwhile it can maintain the respiratory and circulation parameters and reduce adverse reactions.

Adult ; Aged ; Critical Care ; methods ; Delirium ; drug therapy ; etiology ; Dexmedetomidine ; administration & dosage ; Female ; Humans ; Hypnotics and Sedatives ; administration & dosage ; Intensive Care Units ; Length of Stay ; Male ; Midazolam ; administration & dosage ; Middle Aged ; Prognosis ; Prospective Studies ; Respiration, Artificial ; adverse effects ; methods ; Risk Assessment ; Statistics, Nonparametric ; Treatment Outcome ; Ventilator Weaning ; adverse effects ; psychology

OBJECTIVETo investigate the effects of prenatal alcohol exposure on rhythmic respiratory discharge activity (RRDA) in the medullary slices of neonatal rats.

METHODSTen pregnant female SD rats were exposed to 0, 4%, 6%, 8%, and 10% alcohol in drinking water from 1 week before till 3 days after delivery. The medullary slices of the neonatal rats containing the medial region of the nucleus retrofacialis (mNRF) with the hypoglossal nerve rootlets were prepared and perfused with modified Kreb's solution to record RRDA from the hypoglossal nerve rootlets using suction electrodes.

RESULTSNo significant difference was found in RRDA in 50 min among the neonatal rats with prenatal exposure to 0, 4%, 6%, and 8% alcohol, but the RRDA in 10% alcohol exposure group became irregular. Prenatal exposure to increased alcohol concentrations caused attenuated RRDA attenuated in the neonatal rats, shown by shortened inspiratory time (TI), decreased respiratory frequency (RF), and reduced integral amplitude (IA) as compared with those in the control group.

CONCLUSIONPrenatal alcohol exposure inhibits RRDA in medullary slices of neonatal rats, which might be a mechanism by which maternal alcohol exposure causes suppressed offspring respiratory functions.

Animals ; Animals, Newborn ; Ethanol ; adverse effects ; Female ; Hypoglossal Nerve ; drug effects ; physiopathology ; Medulla Oblongata ; drug effects ; physiopathology ; Pregnancy ; Prenatal Exposure Delayed Effects ; Rats ; Rats, Sprague-Dawley ; Respiration ; drug effects

OBJECTIVETo study the analgesic effect and safety of fentanyl in neonates receiving mechanical ventilation.

METHODSThirty neonates receiving mechanical ventilation between December 2010 and February 2011 were randomized into drug intervention group and control group (n=15 each). In addition to the conventional treatment for both groups, the drug intervention group received fentanyl as the analgesic treatment. Heart rate, respiratory rate, blood pressure changes, and premature infant pain profile (PIPP) score before treatment and at 30 minutes, 2 hours, and 4 hours after treatment were recorded in both groups. Follow-up visits were performed for these infants after discharge, and the CDCC intellectual development scale for infants was applied to measure mental development index (MDI) and psychomotor development index (PDI) at 3, 6, 9, and 12 months of age.

RESULTSThe respiratory rate and heart rate decreased in the drug intervention group after fentanyl treatment compared with the control group (P<0.05), and the PIPP scores in the drug intervention group was significantly lower than in the control group (P<0.05). The results of follow-up visits showed no significant differences in MDI and PDI at 3, 6, 9 and 12 months of age between the drug intervention and control groups (P>0.05).

CONCLUSIONSFentanyl can relieve the pain response in neonates receiving mechanical ventilation, with no long-term adverse effects on neurodevelopment.

Analgesics, Opioid ; pharmacology ; Child Development ; drug effects ; Female ; Fentanyl ; pharmacology ; Heart Rate ; drug effects ; Humans ; Infant, Newborn ; Infant, Premature ; Male ; Respiration ; drug effects ; Respiration, Artificial

OBJECTIVETo investigate the effect of different doses of dexmedetomidine (Dex) on early postoperative cognitive dysfunction in elderly patients undergoing laparoscopic surgery for colorectal cancer.

METHODSEighty ASAI-III elderly patients (over 65 years) were randomized equally into 4 groups including a control group without dexmedetomidine and 3 dexmedetomidine groups (groups D1, D2, and D3) with loading dexmedetomidine doses of 0.2, 0.5, and 0.8 µg/kg and maintenance doses of 0.2, 0.5, and 0.8 µg·kg(-1)·h(-1), respectively. Dex was discontinued 30 min before the end of surgery. The time of operation, adverse reactions, time from the end of surgery to spontaneous breathing recovery (TR), time from spontaneous breathing recovery to opening eyes (TO), and time from opening eyes to extubation (TE) were recorded. Mini-Mental State (MMSE) test was used to assess the cognitive function 1 day before and at 1 day and 3 days after the operation.

RESULTSThe incidence of postoperative cognitive dysfunction (POCD) was significantly lower in groups D2 and D3 than in the control group and group D1 (P<0.05). The incidences of hypotension and bradycardia were the highest in group D3 (P<0.05), which also had longer significantly TO and TE than the other 3 groups (P<0.05).

CONCLUSIONDexmedetomidine with a loading dose of 0.5 µg/kg followed by maintenance doses of 0.5 and 0.8 µg·kg(-1)·h(-1) (preferentially 0.5 µg·kg(-1)·h(-1)) can reduce the incidence of POCD in elderly patients undergoing laparoscopic surgery for colorectal cancer.

Aged ; Cognition ; drug effects ; Colorectal Neoplasms ; surgery ; Dexmedetomidine ; administration & dosage ; Humans ; Laparoscopy ; Postoperative Complications ; Respiration

OBJECTIVETo study the clinical significance of tidal breathing lung function test in 1-4 years old children with wheezing diseases.

METHODSA total of 141 1-4 years old children with wheezing diseases were enrolled as the observed groups (41 cases of asthma, 54 cases of asthmatic bronchitis, and 46 cases of bronchopneumonia). Thirty children without respiratory diseases were enrolled as the control group. All the recruits underwent tidal breathing lung function test. The observed groups underwent bronchial dilation test, and tidal breathing flow volume (TBFV) parameters were evaluated before and after bronchial dilation test.

RESULTSThe observed groups showed obstructive ventilatory disorder (65%) according to the TBFV loop, and their ratio of time to peak tidal expiratory flow (TPTEF) to total expiratory time (TE) and ratio of volume to peak expiratory flow (VPEF) to total expiratory volume (VE) were significantly lower than in the control group (P<0.05). The asthma subgroup had significantly improved TPTEF/TE and VPEF/VE after bronchial dilation test (P<0.05). Taking an improvement rate of ≥ 15% either for TPTEF/TE or for VPEF/VE as an indicator of positive bronchial dilation test, the bronchial dilation test had a sensitivity of 47% and a specificity of 84% in diagnosing asthma in 1-4 years old children. The positive rate was 28% among the children in the asthma subgroup with an TPTEF/TE ratio of ≥ 23% before bronchial dilation test, versus 65% in those with an TPTEF/TE ratio of <23%.

CONCLUSIONSObstructive ventilatory disorder is the main impairment of tidal breathing lung function in 1-4 years old children with wheezing diseases. Tidal breathing bronchial dilation test can reflect a reversal of airway obstruction to a certain extent. The sensitivity of bronchial dilation test for the diagnosis of asthma is not satisfactory in 1-4 years old children with wheezing diseases, but this test has a relatively high diagnostic value in children with severe airway obstruction.

Asthma ; diagnosis ; physiopathology ; Bronchitis ; diagnosis ; physiopathology ; Bronchopneumonia ; diagnosis ; physiopathology ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Respiration ; Respiratory Function Tests ; methods ; Respiratory Sounds ; diagnosis ; drug effects ; physiopathology

People complain about nasal stuffiness after SO2 exposure. This study was to investigate the acute effects of SO2 on nasal vascular and airway resistances in anaesthetized pigs for elucidating the underlying vascular and control mechanisms. Controlled ventilation was passed to the lungs or retrogradely through each nasal cavity. Nasal airway and lower airway pressures were measured to reflect airflow resistance changes. Systemic arterial pressure and nasal arterial flow were measured to calculate nasal vascular resistance. Nasal and pulmonary SO2 challenges were given. At 2 ppm, SO2 decreased systemic blood pressure and nasal vascular resistance but increased nasal airway and lower airway resistances. With increasing level to 8 ppm, SO2 increased systemic arterial pressure, nasal vascular and lower airway resistances but decreased nasal airway resistance. Nasal and pulmonary challenges induced similar responses. Ipsilateral nasal challenge elicited bilateral responses. Ruthenium red abolished the responses to nasal challenges. Bilateral vagosympathectomy eliminated the responses to lung challenges. Hence, SO2 at 2 ppm causes nasal congestion through sensory reflex vasodilatation but at higher levels nasal decongestion through sensory reflex vasoconstriction. Nasal congestion coupled with bronchoconstriction at levels of SO2 below short-term exposure limit (STEL) (≤ 2 ppm) would limit SO2 entering the lungs. Nasal decongestion at levels of SO2 beyond STEL (> 2 ppm) can effectively decrease total airway resistance as concurrent strong bronchoconstriction may impair ventilation.
Administration, Inhalation ; Airway Resistance ; drug effects ; Animals ; Lung ; drug effects ; Nasal Cavity ; drug effects ; Respiration ; Sulfur Dioxide ; pharmacology ; Swine ; Vascular Resistance ; drug effects ; Vasodilation

OBJECTIVETo investigate the effects of iron supplement on function of mitochondrial respiratory of liver during exercise-induced hypochromic rats.

METHODForty healthy male Wistar rats were randomized into 5 groups (n = 8): static control (C), exercise-training (T), training with supplementation of small dose iron (S + T), training with supplementation of middle dose iron (M + T) and training with supplementation of large dose iron (L + T). Training performed incremental exercise for 8 weeks, 6 days/week, iron supplementation from the fifth week. Liver were prepared immediately after exhaustive running. Liver mitochondria were extracted by differential centrifugation. Spectrophotometric analysis was used to evaluate activities of electron transport chain complex (C) I-IV in liver mitochondria.

RESULTS(1) C I, CII and CIV activities in T group were increased significantly (P < 0.05, P < 0.01), CI - C IV activities in S + T, M + T and L + T groups were increased significantly (P < 0.05, P < 0.01) compared with those in C group. (2) CII activity in S + T group was increased remarkably (P < 0.05); CIII and CIV activities in M + T group were increased remarkably (P < 0.01); CI - CIV activities in L+ T group were increased remarkably (P < 0.05, P < 0.01) compared with those in T group.

CONCLUSIONLarge load exercise training composite iron supplementation can improve function of mitochondrial respiration of liver and the aerobic capacity. From the athletic ability , the middle dose iron supplementation is better during large load exercise training.

Anemia, Hypochromic ; metabolism ; physiopathology ; Animals ; Cell Respiration ; drug effects ; Hemoglobins ; metabolism ; Iron ; administration & dosage ; pharmacology ; Male ; Mitochondria, Liver ; drug effects ; physiology ; Physical Conditioning, Animal ; Rats ; Rats, Wistar

OBJECTIVETo evaluate the effects of morphine infusion analgesia on behavioural and neuroendocrine stress response and short term outcome in ventilated neonates.

METHODSA randomized, double-blind clinical trial was conducted between August 2010 and April 2011 at the neonatal intensive care unit of Nanjing Children's Hospital Affiliated to Nanjing Medical University. A total of 46 ventilated preterm infants (≥ 32 weeks) and term infants were divided into 2 groups at random. Twenty-two infants in test group received a loading dose (100 µg/kg) of morphine (> 1 h) followed by a continuous infusion [10 µg/(kg·h)] for (70.05 ± 29.05) h, and 24 infants in control group received 5% glucose with the same infusion rate. (1) The ventilatory parameters [respiratory rate (R), frequence (f), peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP), fraction of inspired oxygen (FiO2)], mean blood pressure (MBP) and heart rate (HR) before treatment, at 30 min, 2 h, 6 h, 12 h, 24 h, 48 h after treatment between two groups were compared. (2) Pain was measured by two assessment tools [neonatal pain, agitation and sedation scale (N-PASS) and COMFORT scale] at the same periods. (3) The ventilation duration, the time from withdrawal to extubation, the total oxygen-inhaled time, the side effects and the clinical outcomes [e.g., pulmonary hemorrhage, air leak, patent ductus arteriosus (PDA), necrotizing enterocolitis (NEC), intraventricular hemorrhage (IVH)] between two groups were compared.

RESULTS(1) There were no significant differences in the different ventilatory parameters before and after treatment between two groups at different periods (P > 0.05). There was no significant difference in the average blood pressure of two groups at different periods, but the heart rate reduced at 24 - 48 h after treatment in test group with significant difference as compared to control group (t = -2.152 and -2.513, P < 0.05). (2) The N-PASS score and COMFORT score in test group were lower than that in control group at different time points 2 h after treatment (P < 0.05), especially 12 h after treatment (P < 0.01). (3) There were no significant differences in the ventilation duration, the time from withdrawal to extubation and the total oxygen time between two groups, and also in side effects, the incidence of IVH, white matter damage and the clinical outcomes.

CONCLUSIONContinuous infusion of morphine could relieve pain in ventilated neonates, reduce the stress response and promote the human-machine coordination, but the medication did not show any effects on neurobehavioral development and short term outcome.

Analgesics, Opioid ; administration & dosage ; pharmacology ; Double-Blind Method ; Female ; Humans ; Hyaline Membrane Disease ; therapy ; Infant, Newborn ; Infant, Premature ; Infusions, Intravenous ; Intensive Care Units, Neonatal ; Lung Diseases ; therapy ; Male ; Morphine ; administration & dosage ; pharmacology ; Pain ; drug therapy ; etiology ; Pain Measurement ; methods ; Respiration, Artificial ; adverse effects ; Treatment Outcome