Yuji Sakanashi

Kinetics of macrophage subpopulations and expression of monocyte chemoattractant protein-1 (MCP-1) in bleomycin-induced lung injury of rats studied by a novel monoclonal antibody against rat MCP-1

We investigated the kinetics of macrophage subpopulations and the expression of monocyte chemoattractant protein 1 (MCP‐1) in a rat model of bleomycin‐induced lung injury. Rat macrophage subpopulations were examined by immunohistochemistry using various anti‐rat macrophage monoclonal antibodies (mAbs) and their proliferative capacity by [3H]thymidine (3HTdR) autoradiography. To detect the localization of expressed MCP‐1, we generated an mAb against rat MCP‐1 for immunohistochemical staining. Expression of MCP‐1 messenger RNA (mRNA) was detected by Northern blot hybridization. Shortly after intratracheal instillation of bleomycin, the number of exudate macrophages recognized by mAb TRPM‐3 increased in the injured lungs, peaked 3 days later, and decreased thereafter, whereas tissue macrophages identified by mAb ED2 increased slowly and peaked 2 weeks after instillation. Northern blot analysis disclosed that the expression of MCP‐1 mRNA in the lung was most prominent 1 day after instillation and declined thereafter, preceding the numerical change of the TRPM‐3‐positive exudate macrophages. Immunohistochemistry with anti‐rat MCP‐1 revealed that the main sources of MCP‐1 production were alveolar and interstitial macrophages and polymorphonuclear leukocytes. Based on these results, MCP‐1 produced by polymorphonuclear leukocytes and by alveolar and interstitial macrophages is thought to induce the infiltration of blood monocytes, and infiltrated exudate macrophages produce MCP‐1 to enhance subsequent accumulation of macrophages. In contrast, the expression of MCP‐1 did not correlate with the numerical changes of the ED2‐positive macrophages. J. Leukoc. Biol. 56: 741–750; 1994.

Jugular vein temperature reflects brain temperature during hypothermia

PURPOSE The neuroprotective properties of mild to moderate hypothermia are well recognized but may not be employed correctly because brain temperature cannot usually be measured directly. This study investigated the jugular vein as a more accessible site that accurately reflects the actual brain temperature during mild, induced hypothermia. METHODS We selected ten mongrel dogs (mean weight 12 +/- 2 kg) and measured temperatures of the brain, jugular vein, cisterna magna, pulmonary artery and rectum during hypothermia, including cooling and rewarming. The brain temperature needle probe was inserted 2.0 cm into the parenchyma. A temperature probe was placed in the cisterna magna with an epidural needle. Swan-Ganz thermistor probes measured the jugular venous and pulmonary artery blood temperatures. RESULT The brain temperature decreased from 37.5 +/- 0.3 to 33.0 +/- 0.3 degrees C over an average 150 +/- 45 min cooling period. Stable cool was maintained for 245 +/- 32 min, followed by 165 +/- 50 min for rewarming from 33.5 +/- 0.3 to 37.5 +/- 0.3 degrees C. Jugular, cisterna magna and pulmonary arterial blood (PAB), but not rectal temperature, were close to brain temperature during stable cool. The mean jugular and cisterna magna temperatures were near the brain temperature at 0.1 degrees C higher and 0.1 degrees C lower, respectively. No significant effects of hypothermia were noted on hemodynamics in any phase. CONCLUSION Jugular vein temperature, along with cisterna magna and pulmonary artery blood and rectal temperature, reflected brain temperature during hypothermia. The jugular vein and cisterna magna sites more sensitively reflected brain temperature than other sites.

Preliminary experiment with a newly developed double balloon, double lumen catheter for extracorporeal life support vascular access.

Recently, venovenous extracorporeal life support (VVECLS) using a double lumen catheter has been clinically used to avoid neurologic complications in the treatment of respiratory failure for neonates. However, recirculation, which is a limiting factor for oxygen delivery, still exists, and thus it does not contribute to oxygenation of the patient. We developed a newly designed double lumen catheter with a double balloon (DBDL) catheter for ECLS vascular access and performed two animal preliminary experiments in normal and hypoxic dog models (normal ventilation and one lung ventilation experiments) to investigate whether the DBDL catheter could prevent recirculation and maintain oxygen delivery to systemic circulation. The DBDL catheter (JCT Co., Hiroshima, Japan) of 15 Fr was fabricated from silicone. It consists of two lumens for drainage and return of blood with two balloons (distal and proximal balloons) that prevent oxygenated blood mixing with unoxygenated blood. VVECLS using a DBDL catheter was performed in 13 mongrel dogs (8 dogs for normal ventilation experiment weighing 12.9 ± 1.6 kg [mean ± SD], 5 dogs for one lung ventilation experiment weighing 16.6 ± 2.5 kg [mean ± SD]) under anesthesia in the two experiments. The bypass flow ranged from 10–40 ml/kg per minute in the normal ventilation experiment. VVECLS in the one lung ventilation experiment was performed with maximal bypass flow for 6 hours (ranged from 25.2 ± 8.0–28.3 ± 8.7 ml/kg per minute at balloon inflation and deflation). Recirculation and oxygen transfer of artificial lung with or without balloon inflation during VVECLS were studied. Recirculation decreased with balloon inflation at varied bypass flows during VVECLS in the normal ventilation experiment (varied from 1.5 ± 14.6–12.8 ± 16.7%) and for 6 hours after VVECLS initiation in the one lung ventilation experiment (varied from 12.2 ± 12.2–19.2 ± 6.5 %). In particular, the values at 3 and 6 hours were significantly lower than that of balloon deflation in the one lung ventilation experiment. The difference in O2 content between inlet and outlet in the artificial lung with balloon inflation was significantly higher than that of balloon deflation (varied from 3.7 ± 1.8–4.8 ± 1.9 ml/dl, p < 0.05) at the bypass flow of 10–30 ml/kg per minute in the normal ventilation experiment and at 5 hours after VVECLS initiation in the one lung ventilation experiment (varied from 10.6 ± 1.6–11.7 ± 1.8 ml/dl). The blood gas analysis of systemic circulation with balloon inflation revealed that the values of PaO2 (varied from 83.8 ± 11.4–96.9 ± 23.4 mm Hg) and PaCO2 (37.7 ± 9.2–40.4 ± 11.8 mm Hg) were higher and lower, respectively, compared with balloon deflation. In particular, PaO2 level was significantly higher than that of the preECLS value at the bypass flow of 20–40 ml/kg per minute (varied from 83.8 ± 11.4–96.9 ± 23.4 mm Hg, p < 0.05). In the one lung ventilation experiment, systemic PaO2 and PaCO2 levels at balloon inflation were higher and lower, respectively, compared with balloon deflation during VVECLS for 6 hours. At balloon inflation, the value of PaO2 at 6 hours after VVECLS initiation was significantly higher than that at balloon deflation. A newly designed DBDL catheter for ECLS vascular access successfully reduced recirculation and maintained oxygen delivery to systemic circulation during VVECLS. These results suggest that a high bypass flow may not be necessarily required in terms of oxygen delivery to systemic circulation when the DBDL catheter was used as an ECLS vascular access.

Acute respiratory failure induced by mechanical pulmonary ventilation at a peak inspiratory pressure of 40 cmH20

The effects of high pressure mechanical pulmonary ventilation at a peak inspiratory pressure of 40 cmH20 were studied on the lungs of healthy newborn pigs (14–21 days after birth). Forty percent oxygen in nitrogen was used for ventilation to prevent oxygen intoxication. The control group (6 pigs) was ventilated for 48 hours at a peak inspiratory pressure less than 18 cmH20 and a PEEP of 3–5 cmH20 with a normal tidal volume, and a respiratory rate of 20 times/min. The control group showed few deleterious changes in the lungs for 48 hours. Eleven newborn pigs were ventilated at a peak inspiratory pressure of 40 cmH20 with a PEEP of 3–5 CmH20 and a respiratory rate of 20 times/min. To avoid respiratory alkalosis, a dead space was placed in the respiratory circuit, and normocarbia was maintained by adjusting dead space volume. In all cases in the latter group, severe pulmonary impairments, such as abnormal chest roentgenograms, hypoxemia, decreased total static lung compliance, high incidence of pneumothorax, congestive atelectasis, and increased lung weight were found within 48 hours of ventilation. When the pulmonary impairments became manifest, 6 of the 11 newborn pigs were switched to the conventional medical and ventilatory therapies for 3–6 days. However, all of them became ventilator dependent, and severe lung pathology was found at autopsy. These pulmonary insults by high pressure mechanical pulmonary ventilation could be occurring not infrequently in the respiratory management of patients with respiratory failure.

Heparin bonding of the extracorporeal circuit reduces thrombosis during prolonged lung assist in goats.

This study investigated whether an artificial membrane lung of nonmicroporous polyolefin hollow fibers bonded with heparin could prolong venoarterial extracorporeal lung assist (ECLA) with low dose systemic heparin in goats. We compared heparin bonded circuits (Carmeda Bioactive Surface, “HB” group, n = 5) with non heparin bonded circuits (“NHB” group, n = 5) in venoarterial ECLA (V-A ECLA) for 7 days. Activated coagulation time (ACT) was maintained at approximately 130 sec by systemic infusion of small doses of heparin in the HB group, and at 200–230 sec in the NHB group. Thrombus formation was assessed by visual examination of the circuit, and possible cerebral embolization of thrombi was observed from behavioral abnormalities of the animals. The mean heparin dose given during ECLA was 20.4 ± 3.6 U/kg per hr in HB, and 50.9 ± 14.2 U/kg per hr in NHB, significantly less in HB than NHB (p < 0.01). Blood gas changes across the oxygenator, bypass flow rate, platelet aggregation activity, platelet counts, fibrin monomer (FM) test, and antithrombin-III (AT-III) activity did not differ between the two groups. In HB, thrombi were fewer and no abnormal neurologic symptoms were observed during ECLA. Numerous thrombi were observed in all oxygenators with NHB. One NHB goat developed convulsions and cerebral hemorrhage on the 6th day of ECLA. Nonmicroporous polyolefin hollow fibers can be bonded with heparin. An artificial membrane lung constructed of these fibers showed good anticoagulation by decreased thrombus formation with a small dose of infused heparin.

Newborn extracorporeal lung assist using a novel double lumen catheter and a heparin-bonded membrane lung

We report the clinical application of a novel double lumen catheter for veno-venous extracorporeal lung assist (ECLA) and the use of a heparin-bonded hollow fiber membrane lung, in the treatment of newborn respiratory failure. The outer lumen of the double lumen catheter was 14 Fr and was used for blood drainage; while the inner 8 Fr catheter was used for blood return. The double lumen catheter was made of spiral wire reinforced polyurethane, with a wall thickness of 0.25 mm. The hollow fiber membrane was made of non-microporous polyolefin, and was not permeable to water or plasma. We used this system to treat a newborn patient with meconium aspiration syndrome. Heparin was infused continuously at a rate of 18–25 units/kg/h, equal to 1/3 of the usual amount when a non-heparin bonded ECLA system was used and maintaining the activated clotting time near 120 s. Bleeding from cutdown sites was negligible. Only the right internal jugular vein was sacrificed. The patient was successfully weaned from ECLA and appears normal one year following discharge.

Simple and noninvasive indicator of pulmonary gas exchange impairment using pulse oximetry.

We postulated that the fractional inspired oxygen concentration (FiO2) required to achieve a certain value of arterial oxygen saturation (SaO2) can be used as an indicator of pulmonary gas exchange impairment in patients during mechanical ventilation. We tested this hypothesis in 20 patients. By reducingFiO2 in increments of 10 vol% of capacity while monitoring SaO2 with pulse oximetry, we could determineFi98,Fi97,Fi96, andFi95; that is, the yields 98, 97, 96, and 95% SaO2, respectively. On the basis of our data, we choseFi98 as the most appropriate index, as an SaO2 of 97% or below could not be achieved even with a lowFiO2 in some of the patients. To test the significance of the newly proposed index, we comparedFi98 with the alveolar-arterial oxygen tension difference, P(A−a)O2, and with the respiratory index, which are routinely used elsewhere. The correlation betweenFi98 and P(A−a)O2 was excellent: P(A−a)O2=490.5*Fi98+117.2 with a correlation coefficient of 0.906 (P<0.01).Fi98 also correlated significantly with the respiratory index: respiratory index=4.354*Fi98−0.776 (r=0.889,P<0.01).We conclude thatFi98 may be used as a simple index for the rough estimation of pulmonary gas exchange impairment without the need for invasive procedures. However, further studies are needed to confirm the validity of our method in hemodynamically unstable patients or when other brands of pulse oximeters are used.

Does veno-arterial bypass without an artificial lung improve the outcome in dogs undergoing cardiac arrest?

We hypothesized that maintaining circulation and blood pressure by veno-arterial bypass (V-A bypass) without oxygenation would improve cardiopulmonary resuscitation (CPR) and survival rates. A total of 32 dogs, divided into four groups, were subjected to normothermic ventricular fibrillation (VF) for 15 min. The method of CPR was the same in the four groups, except for the method and timing of V-A bypass. We attempted to resuscitate the dogs without V-A bypass (control), with V-A bypass not including an artificial lung during VF, with V-A bypass not including an artificial lung during CPR, and with V-A bypass including an artificial lung during CPR. CPR was continued until restoration of spontaneous circulation (ROSC) or for 30 min. Although blood pressure was well maintained, severe hypoxemia was observed during V-A bypass without an artificial lung. The resultant hypoxemia was very detrimental. ROSC was achieved more easily in all dogs in the bypass group with an artificial lung. No significant difference in survival rates was demonstrated among the four groups (P = 0.11). We concluded that V-A bypass without oxygenation does not improve the chances for CPR and outcome after cardiac arrest in dogs. Our results suggest that oxygenation is indispensable in CPR.

Total and prolonged filling of the lungs with Ringer’s solution under extracorporeal lung assist (ECLA) in dogs

Background: Massive alveolar lavage has been used clinically to remove materials accumulated in the alveoli. Recently, filling the lungs with oxygenated perfluorochemical (total liquid ventilation) has been investigated. However, effects of complete and prolonged filling of bilateral lungs with aqueous fluid, such as saline or Ringer’s solution, has not been evaluated, although it is possible to sustain gas exchange without the natural lung by using extracorporeal circulation and an artificial lung (extracorporeal lung assist: ECLA). It is also not known whether the lung can recover gas exchange ability after prolonged fluid filling.

Detachment of a venous cannula into a blood vessel

To the editor: There have been a number of reports of catheter breakage, but none describing detachment of a venous cannula from the hub. We recently experienced such a detachment during acute normovolemic hemodilution. Hemodilution enables collection of autologous blood that helps limit complications from homologous blood transfusion. We cannulate a large vein, such as the external jugular vein, with a Wallace Y-Can catheter and then insert the needle attached to a blood collection bag (NiproC400) into the catheters rubber seal. In this way, we are able to collect more than two bags of blood without repeat venipuncture. An incident occurred in a 51-year-old woman undergoing modified radical hysterectomy for a malignant ovarian tumor. After lumbar epidural block, general anesthesia was initiated with fentanyl and thiamylal. Oral intubation was facilitated with the administration of vecuronium bromide. Anesthesia was maintained with nitrous oxide and isoflurane in oxygen. Acute normovolemic hemodilution was started by collecting a first aliquot of 400 ml of blood through the Y-Can catheter inserted at the left external jugular vein, while lactated Ringers solution was infused through the left radial vein. No difficulty was encountered with this first extraction. However, with the insertion of the needle of the second bag into the catheters rubber seal, there was no backward flow of blood. When the tape covering the puncture site was removed, the cannula portion of the catheter was found to be missing. Palpation of the puncture site revealed that the dislodged fragment was still present. Pressure on the external jugular