Effect of transjugular intrahepatic portosystemic shunt on pulmonary gas exchange in patients with portal hypertension and hepatopulmonary syndrome

AIM: To assess the impact of transjugular intrahepatic portosystemic shunt (TIPS) on pulmonary gas exchange and to evaluate the use of TIPS for the treatment of hepatopulmonary syndrome (HPS).METHODS: Seven patients, three of them with advanced HPS, in whom detailed pulmonary function tests were performed before and after TIPS placementat the University of Alabama Hospital and at the Hospital Clinic, Barcelona, were considered.RESULTS: TIPS patency was confirmed by hemodynamic evaluation. No changes in arterial blood gases were observed in the overall subset of patients. Transient arterial oxygenation improvement was observed in only one HPS patient, early after TIPS, but this was not sustained 4 mo later.CONCLUSION: TIPS neither improved nor worsened pulmonary gas exchange in patients with portal hypertension. This data does not support the use of TIPS as a specific treatment for HPS. However, it does reinforce the view that TIPS can be safely performed for the treatment of other complications of portal hypertension in patients with HPS.

Sustained low diffusing capacity in hepatopulmonary syndrome after liver transplantation

AIM： To study the presence of sustained low diffusing capacity （DLco） after liver transplantation （LT） in patients with hepatopulmonary syndrome （HPS）. METHODS： Six patients with mild-to-severe HPS and 24 without HPS who underwent LT were prospectively followed before and after LT at mid-term （median, 15 mo）. HPS patients were also assessed at Iong-tem （median, 86 mo）. RESULTS： Before LT, HPS patients showed lower PaO2 （71 ± 8 mmHg）, higher AaPO2 （43 ± 10 mmHg） and lower DLco （54% ± 9% predicted）, due to a combination of moderate-to-severe ventilation-perfusion （VA/Q） imbalance, mild shunt and diffusion limitation, than non- HPS patients （94 ± 4 mmHg and 19 ± 3 mmHg, and 85% ± 3% predicted, respectively） （P 〈 0.05 each）. Seven non-HPS patients had also reduced DLco （70% ± 4% predicted）. At mid- and long-term after LT, compared to pre- LT, HPS patients normalized PaO2 （91 ± 3 mmHg and 87 ± 5 mmHg）, AaPO2 （14 ± 3 mmHg and 23 ± 5 mmHg） and all VA/Q descriptors （P 〈 0.05 each） without changes in DLco （53% ± 8% and 56% ± 7% predicted, respectively）. Post-LT DLco in non-HPS patients with pre- LT low DLco was unchanged （75% ± 6% predicted）. CONCLUSION： While complete VA/Q resolution in HPS indicates a reversible functional disturbance, sustained low DLco after LT also present in some non-HPS patients, points to persistence of sub-clinical liver-induced pulmonary vascular changes.

Effect of Two Administration Routes of Shenmai Injection(参麦注射液)on Pulmonary Gas Exchange Function after Tourniquet-Induced Ischemia-Reperfusion

Objective： To compare the effect between nebulized and intravenous administration of Shenmai Injection （参麦注射液） on pulmonary gas exchange function of patients following tourniquet-induced lower limb ischemia-repeffusion. Methods： Thirty-eight patients scheduled for lower extremity surgery were randomized into three groups using the closed envelop method： Shenmai Injection was administered 30 min before tourniquet inflation by nebulization [0.6 mL/kg in 10 mL normal saline （NS）] in the nebulization group or by intravenous drip （0.6 mL/kg dissolved in 250 mL of 10% glucose） in the intravenous drip group, and equal volume of NS was given intravenously in the NS group; 15 in each group. Arterial blood gases were analyzed, serum levels of malonaldehyde （MDA） and interleukine-6 （IL-6） and interleukine-8 （IL-8） were determined using the method of thiobarbituric acid reaction and enzyme-linked immuno sorbent assay respectively just before tourniquet inflation （TO）, and at 0.5 h （T1）, 2 h （TZ）, 6 h （T3） after tourniquet deflation. Results： Compared with baselines at TO, MDA levels significantly increased at TZ, T3 in the NS group and at T3 in the nebulization group, and IL-6 and IL-8 levels were significantly increased at TZ, T3 in NS, the intravenous drip and the nebulization groups （P〈0.05）. Arterial pressure of oxygen （PaO2） at T3 was decreased, while alveolar- arterial oxygen tension showed difference （PA-aDO2） at T3 in the NS group; RI at T3 in both intravenous drip and the nebulization groups were enhanced （P〈0.05）. Compared with the NS group, MDA and IL-8 levels at TZ, T3, 11-6 at T3 in the intravenous drip group, and IL-8 at T3 in the nebulization group were all remarkably increased （P〈0.05）. Additionally, MDA level at T3 in the nebulization group was higher than that in the intravenous drip group （P〈0.05）. Conclusions： Intravenous administration of Shenmai Injection provided a better protective effect than nebulization in mitigating pulmonary gas exchange dysfunction in patients following tourniquet-induced limb ischemia-repertusion.

Roles of NHE-1 in the proliferation and apoptosis of pulmonary artery smooth muscle cells in rats

Objective To evaluate the roles of Na +/H + exchanger-1 (NHE-1)in the proliferation and apoptosis of pulmonary artery smooth muscle cells in rats. Methods Twenty Wistar rats were randomized into control group and 3-week hypoxic group. Intracellular pH (pHi) of the smooth muscle was determined with fluorescence measurement of the pH-sensitive dye BCECF-AM, and the expression of NHE-1 mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). Primary culture of pulmonary artery smooth muscle cells in vitro was performed. In situ cell death detection kit (TUNEL) was used for studying the effect of specific NHE-1 inhibitor-dimethyl amiloride (DMA) on the apoptosis of muscle cells which had intracellular acidification. Results pHi value and NHE-1 mRNA expression of pulmonary artery smooth muscle cells were significantly higher in the hypoxic group than in the control group (P【0.01, P【0.001). DMA elevated the apoptotic ratio remarkably. The effect was enhanced when DMA concentration increased and the time prolonged.Conclusions With the function of adjusting pHi, NHE-1 may play an important role in the proliferation and apoptosis of pulmonary artery smooth muscle cells.

Proportional assist ventilation: methodology and therapeutics on COPD patients compared with pressure support ventilation

OBJECTIVE: To investigate the impact of proportional assist ventilation (PAV) on tolerance and breathlessness in ventilated chronic obstructive pulmonary disease (COPD), and to describe the patient-ventilator interaction, hemodynamic state, breathing pattern and work of breath during PAV and pressure support ventilation (PSV). METHODS: Ten intubated COPD patients on weaning from mechanical ventilation were studied. Elastance and resistance were measured by both the inspiratory-hold technique during a brief period of volume control ventilation and runaway technique during PAV. Each assistance level of PAV (80%, 60% and 40%) and PSV was selected randomly. Patients' response, hemodynamics, blood gas and lung mechanics were monitored. RESULTS: Tidal volume and respiratory rate didn't change in a consistent manner as the level of assist was decreased (P > 0.05). With the level of assist increasing, peak inspiratory pressure was increasing significantly (P