Effect of decreased fetal perfusion on placental clearance of volatile anesthetics in a dual perfused human placental cotyledon model.

Placental transfer of volatile anesthetics is a critical issue in managing fetal distress during cesarean section under general anesthesia. Using dual perfused human placental cotyledons obtained from parturients undergoing elective cesarean section (n = 5), we investigated the effect of decreased fetal perfusion on placental clearance of sevoflurane and isoflurane. Keeping the maternal flow rate fixed, fetal flow rate was consecutively decreased from 3 ml/min (control perfusion) to 2 ml/min (intermediate perfusion) and to 1 ml/min (hypoperfusion). Placental transfer was assessed by the clearance of anesthetics by the placenta, defined by the ratio of anesthetic concentration in fetal vein and maternal artery, multiplied by fetal flow rate. Placental clearance was compared between different fetal perfusion states and anesthetics. Hypoperfusion resulted in a lower clearance of sevoflurane and isoflurane compared with control (P = 0.002, P < 0.001) and intermediate (P = 0.04, P = 0.018) perfusion. Clearances of sevoflurane and isoflurane were comparable during control perfusion (P = 0.93), intermediate perfusion (P = 1.00), and hypoperfusion (P = 0.88). Thus, maintenance of volatile anesthetics at a marginally low concentration may not be necessary when fetal distress is observed during emergency cesarean delivery because placental transfer of volatile anesthetics decreases with decreasing fetal perfusion.

Utility of the Pentax-AWS Airwayscope and Macintosh laryngoscope for airway management during chest compressions in 27° left-lateral tilt: a manikin simulation study of maternal cardiopulmonary resuscitation.

PURPOSE: American Heart Association (AHA) 2010 cardiopulmonary resuscitation guidelines recommend high-quality chest compressions (minimum interruption, a pace >100 compressions/min, and a depth more than 5 cm). They propose minor changes for pregnant women: manual left deviation of the uterus or a left-lateral incline of 27°-30° to alleviate pressure on the inferior vena cava. We examined the performance of the Pentax-AWS Airwayscope (AWS) and Macintosh laryngoscope (McL) for airway management during chest compressions on a 27° left-lateral tilt (27 LLT) operating table. METHODS: The study included 18 novice doctors in our anesthesia department. They performed tracheal intubation on a manikin positioned on a 27 LLT operating table using the AWS or McL with or without chest compressions. We measured the intubation time and success rate for tracheal intubation. RESULTS: Intubation success rate with the McL decreased with chest compressions compared to without chest compressions (12/18 vs. 18/18, P < 0.05). Intubation time with the McL was lengthened with chest compressions compared to without chest compressions (18.9 ± 4.0 s vs. 11.1 ± 1.0 s, P < 0.05). Intubation success rate was the same for the AWS with and without chest compressions (18/18 in both cases), and intubation time did not increase significantly without compressions compared to with compressions (11.6 ± 1.4 s vs. 12.6 ± 1.2 s, NS). CONCLUSIONS: The AWS is an effective tool for airway management during chest compressions in 27 LLT in a manikin, suggesting that the AWS may be a useful device for airway management during maternal resuscitation.

Comparison of Pentax-AWS Airwayscope, Airtraq and Miller laryngoscope for tracheal intubation by novice doctors during infant cardiopulmonary resuscitation simulation: a randomized crossover trial.

Recent guidelines for infant cardiopulmonary resuscitation emphasize that all rescuers should minimize interruption of chest compressions, even for endotracheal intubation. We compared the utility of the Pentax-AWS Airway Scope (AWS) with an infant-sized Intlock (AWS-I), Airtraq laryngoscope (ATQ) and Miller laryngoscope during chest compressions on an infant manikin. Twenty-three novice doctors performed tracheal intubation on an infant manikin using the AWS-I, ATQ and Miller laryngoscope, with or without chest compressions. In Miller laryngoscope trials, one participant failed to secure the airway without chest compressions, while nine failed with compressions (P < 0.05). In ATQ trials, none of the participants failed without compressions, while six failed with compressions (P < 0.05). In AWS-I trials, all participants succeeded regardless of chest compressions. Intubation time was significantly longer with chest compressions with the Miller laryngoscope and ATQ, but not with the AWS-I. The AWS-I is an effective device for endotracheal intubation during chest compressions in infant simulations managed by novice doctors.

[A case of awake intubation using the Pentax-AWS airwayscope in a patient with a difficult airway combined with severe hemorrhagic shock].

We report a case of awake intubation in a patient with a difficult airway combined with severe hemorrhagic shock using the Pentax-AWS Airwayscope (AWS). A 65-year-old man experienced severe hemorrhagic shock due to diaphragmatic hernia after extrapleural pneumonectomy and was scheduled for emergent exploratory thoracotomy under general anesthesia. Blood pressure was maintained with dopamine-noradrenaline support, and rapid transfusion. We anticipated difficult ventilation due to a swollen face and tongue. The patient underwent awake intubation with the AWS under dexmedetomidine sedation and lidocaine spray for laryngotracheal anesthesia. The patient did not buck during intubation and hemodynamic changes were minimal.

[Application of air-Q laryngeal airway and gum elastic bougie in a case of anticipated difficult. Mask ventilation and tracheal intubation in a man with morbid obesity].

A 46-year-old man was diagnosed with descending colon cancer and was planned to undergo left hemicolectomy under general anesthesia. His body mass index was 42.6 and due to his small mouth and jaw, we anticipated difficult mask ventilation and tracheal intubation. To avoid 'can't ventilate, can't intubate', we first inserted a size 3.5 air-Q laryngeal airway under moderate sedation, maintaining spontaneous ventilation. After confirming sufficient assisted ventilation, we used a bronchofiberscope to visualize placement of a gum elastic bougie in the trachea via the air-Q. Then, we replaced the air-Q with an outside diameter 8.5 mm tracheal tube. This case was a successful use of the air-Q under moderate sedation for airway management in the setting of anticipated difficult mask ventilation and tracheal intubation.

[Use of the air-Q intubating laryngeal airway for tracheal intubation in predicted difficult airway management in a pediatric patient].

The intubating laryngeal airway, air-Q ILA, was recently introduced in Japan. It has been used in adult patients for difficult airway management; however, there are few reports available on its use in pediatric patients. We report the use of the air-Q ILA in predicted difficult airway management in a 16-month-old patient with Apert syndrome characterized by acrocephalosyndactyly undergoing a syndactyly operation. It was somewhat difficult to keep his airway with a facemask, and an air-Q ILA was inserted. Following the ventilation via air-Q ILA, tracheal intubation guided by a tracheal fiberscope was attempted through the air-Q ILA. Five months after this operation, the patient again underwent the same operation. We managed his airway in the same way as previously, and the tracheal was intubated. This case shows that the air-Q ILA can be an alternative device in pediatric difficult airway management.

[Use of the air-Q laryngeal airway and tube exchanger in a case of difficult tracheal extubation after maxillectomy].

A 79-year-old man was diagnosed with maxillary cancer and underwent total maxillectomy under general anesthesia. The oropharyngeal airway was needed for efficient mask ventilation during anesthesia induction. The maxilla was totally resected and reconstructed with skin from a femoral flap. Tracheal extubation was considered to be difficult given that mask ventilation was contraindicated due to reconstruction of the maxilla. After inserting a tube exchanger (TE) into the trachea, the tracheal tube was exchanged with an air-Q laryngeal airway through the TE. After confirming effective ventilation with the air-Q mask, the patient was awakened from anesthesia. We confirmed sufficient spontaneous breathing and no active bleeding in the pharynx. After re-inserting the TE thorough air-Q, the air-Q was removed, followed by removal of the TE. These findings suggest that the air-Q and TE were effective in a case of difficult extubation after maxillectomy.

Hydration status after overnight fasting as measured by urine osmolality does not alter the magnitude of hypotension during general anesthesia in low risk patients.

BACKGROUND: The increased distribution of crystalloid solution into the interstitial space may decrease the effectiveness of intravascular volume loading in patients. We investigated whether preoperative hydration status after overnight fasting affects interstitial fluid redistribution and thus the magnitude of hypotension during general anesthesia. METHODS: Sixty ASA physical status I/II patients undergoing tympanoplasty fasted from midnight. Anesthesia was induced by fentanyl and propofol and maintained with sevoflurane and remifentanil. Coinciding with the induction of anesthesia, 15 mL/kg acetated Ringer solution was infused IV over 60 minutes followed by 1 mL/kg acetated Ringer solution over the next 30 minutes. Urine osmolalities after induction of anesthesia and during the study period (pre-U(osm), post-U(osm)) and percent decreases of whole-body bioelectrical resistance for extracellular fluid relative to baseline at the end of the study period (ΔR(e)) were measured. Patients with a pre-U(osm) < the 25th percentile or with a pre-U(osm) > the 75th percentile of pre-U(osm) were categorized in the hydrated or the dehydrated group, respectively. A range of variables, including mean arterial blood pressure during the 30- to 90-minute period relative to baseline, and ΔR(e), were compared between the groups. RESULTS: The dehydrated group (pre-U(osm) >759.5 mOsm/kg, n = 15) had a lower age (44 vs 52 years, P = 0.049) and had a higher post-U(osm) (181 vs 55 mOsm/kg, P = 0.001) compared with the hydrated group (pre-U(osm) <378.5 mOsm/kg, n = 15). Mean arterial blood pressure during the 30- to 90-minute period relative to baseline (0.67 vs 0.67, P = 0.85) with 95% confidence interval for the difference of means (-0.070 to 0.084) and ΔR(e) (5.6% vs 6.0%, P = 0.58) with 95% confidence interval for the difference of means (-1.85% to 1.06%) were similar for the hydrated and dehydrated groups. CONCLUSIONS: Preoperative dehydration after overnight fasting as measured by urine osmolality did not alter the magnitude of hypotension during general anesthesia. This finding suggests that intravascular volume loading with crystalloid solution to prevent hypotension during general anesthesia is an unfounded practice for low risk patients after overnight fasting.

[Case of awake intubation in semi-sitting position for a patient with myasthenia gravis combined with cervical disc hernia utilizing Pentax-AWS Airwayscope].

We report a case of awake intubation utilizing Pentax-AWS Airwayscope in semi-sitting position. A 74-year-old man with myasthenia gravis and cervical disc hernia was scheduled for distal gastrectomy under general anesthesia. He could not move his head due to severe cervical disc hernia and also could not sufficiently breathe due to the fatigue of respiratory muscles by myasthenia gravis in supine position. With fentanyl bolus administration and lidocaine spray for laryngotracheal anesthesia, we performed awake intubation in semi-sitting position with AWS from cranial side. The patient did not buck during intubation and no hemodynamic change was observed.

[Intubating laryngeal mask airway for fiberoptic bronchoscopy in a woman with right bronchial tumor].

A 37-year-old woman with bronchial tumor was scheduled for the removal of the mass with fiberoptic bronchoscope. Intubating laryngeal mask airway (ILMA) was used for fiberoptic surgery. Through a size 3 ILMA, a 5.9 mm outer diameter fiberoptic bronchoscope reached the trachea easily. The operation was successfully performed with assisted ventilation. Intraoperative laryngospasm was treated with intravenous suxamethonium. The ILMA allowed removal of the bronchial tumor with fiberoptic bronchoscope.

[Efficacy of cryoprecipitate transfusion for coagulopathy after cardiopulmonary bypass in thoracic aortic surgery].

BACKGROUND: Excessive bleeding after cardiopulmonary bypass remains a major complication for cardiac surgery. The principal causes of hemostatic bleeding are related to inadequate surgical hemostasis or diluted coagulopathy. We investigated the efficacy of cryoprecipitate (Cryo) transfusion in thoracic aortic surgery with cardiopulmonary bypass. METHODS: We divided 30 patients undergoing thoracic aortic surgery into two groups retrospectively. Fifteen patients transfused with cryoprecipitate and fresh frozen plasma (FFP) were defined as Group Cryo, and the other 15 patients transfused with FFP only were defined as Group FFP We compared the amount of blood products administered and the blood loss during the perioperative period between the two groups with P <0.05 to be significant. RESULTS: There were no significant differences in the clinical background between the two groups. There were significant differences in the volume of blood loss (Group Cryo 544 +/- 233 ml, Group FFP 888 +/- 339 ml), requirements of FFP (Group Cryo 0.6 +/- 1.7 unit, Group FFP 4.3 +/- 6.0 unit) in ICU. CONCLUSIONS: Cryoprecipitate transfusion is an effective treatment for coagulopathy caused by dilution of coagulation factors after cardiopulmonary bypass.

[Spinal anesthesia for cesarean section--safe and effective anesthetic management].

Spinal anesthesia is a safe and effective anesthetic technique for cesarean section, considering its simplicity, rapidity, accompanied maternal awareness and distribution of anesthetic agents. The problems of spinal anesthesia, hypotension, postdural puncture headache, failed spinal anesthesia, and its duration, have been investigated. Intravenous fluid therapy may reduce the incidence and severity of the hypotension. Colloid administration is one of the interventions for prevention of hypotension. Low dose phenylephrine is effective without fetal acidosis in healthy mother. The fluid and vasoconstrictor therapies for hypotension induced by spinal anesthesia were briefly reviewed. Postdural puncture headache is one of the troublesome problems. Epidural blood patch is one of the definitive treatments; however further randomized trials are required. Spinal opioid has improved the quality of spinal anesthesia. The recommended dose of spinal opioid in the recent obstetric anesthesia textbooks has been reviewed. The recent issue about safety and effectiveness in obstetric anesthesia has been briefly discussed.

[Case of tension pneumothorax associated with asthma attack during general anesthesia].

We report a case of tension pneumothorax associated with asthma attack during general anesthesia. An 86-year-old woman with dementia underwent cataract surgery under general anesthesia. At 70 min after the start of operation, airway pressure suddenly increased from 19 to 28 cm HO2O. In spite of bag ventilation with 100% oxygen, Sp(O2) decreased to 81%. Chest-Xp showed typical image of tension pneumothorax. Chest drainage was immediately performed, after which Pa(O2) recovered soon. She was extubated on postoperative day 1 without any neurological disorder. Hyperinflation of fragile alveoli by mechanical ventilation was likely a cause of tension pneumothorax.

[Combined epidural-spinal anesthesia for radical hysterectomy in a patient complicated with bronchiectasis diagnosed on preoperative anesthetic consultation].

A radical hysterectomy was performed in a patient complicated with bronchiectasis, under combined spinal-epidural anesthesia. The patient was asymptomatic and preoperatively diagnosed with bronchiectasis on an anesthetic consultation with an anesthesiologist. An epidural catheter was inserted between T12 and L1, and spinal anesthesia was subsequently performed with 0.5% bupivacaine 2.8 ml and fentanyl 10 microg. It was necessary to administer a supplemental epidural dose of 0.375% ropivacaine fifty minutes after the start of the operation. Postoperative epidural analgesia was effective and no perioperative complications were observed.

[Anesthetic management for pneumonectomy in a patient with cardiac amyloidosis].

Cardiac amyloidosis may cause restrictive cardiomyopathy associated with heart failure, conduction disorder and ischemic heart disease. Therefore, patients with amyloidosis require careful hemodynamic monitoring in perioperative period. A 63-year-old man with cardiac amyloidosis was scheduled for pneumonectomy. His transthoracic echocardiography assessment showed a hypertrophic interventricular septum and slight decreased ejection fraction of 55%, but left ventricular (LV) diastolic function was decreased. Pulse Doppler for mitral valve inflow showed that the early peak velocity/atrial peak velocity (E/A) ratio was 0.9, the deceleration time (DT) was 163 msec and the early diastolic mitral annular tissue velocity (E') was 4 cm x sec(-1). These data suggested a pseudonormalization state. We performed careful monitoring using arterial pressure-based cardiac output (APCO), central venous oxygen saturation (ScvO2) and transesophageal echocardiography. There were no severe complications such as circulatory collapse and arrhythmia in the perioperative period.

The effect of duration of surgery on fluid balance during abdominal surgery: a mathematical model.

BACKGROUND: There is controversy regarding which fluid management regimen provides the best postoperative outcome. Interstitial fluid accumulation may adversely affect postoperative outcome, but the effect of surgical duration on fluid balance is unknown. In this study, we used a mathematical model to describe fluid distribution. METHODS: Previously published data from bioimpedance analysis in patients undergoing abdominal surgery were used to calculate changes to interstitial volume (DeltaV(IT), percent change relative to baseline) in uninjured and injured tissues. Ratios of DeltaV(IT) in uninjured and injured tissues at the end of surgery to total fluid volume infused during surgery (V(INF), mL/kg) were compared between surgeries of duration <3 h (n = 5) and > or = 3 h (n = 25). Critical values for change in plasma volume (DeltaV(PL), percent change relative to baseline) and DeltaV(IT), which give rise to adverse outcome, were calculated from previously published data on the physiological effects of IV fluid administration in healthy volunteers. Finally, simulated abdominal surgery in a 70 kg man for 1-8 h was used to determine the effect of crystalloid infusion rate between 2 and 30 mL x kg(-1) x h(-1) on DeltaV(PL) and DeltaV(IT). Fluid infusion rates that maintained DeltaV(PL) and DeltaV(IT) in uninjured tissue within critical values were then computationally determined as a function of duration of surgery. RESULTS: Bioimpedance data showed that the differences in DeltaV(IT)/V(INF) ratios between uninjured and injured tissues were significant only for surgical duration > or = 3 h (0.30 +/- 0.17% x kg/mL vs 1.55 +/- 0.73% x kg/mL, P < 0.0001). Differences of DeltaV(IT)/V(INF) ratios between surgical durations <3 and > or = 3 h were found only for injured tissue (0.45 +/- 0.35% x kg/mL vs 1.55 +/- 0.73% x kg/mL, P = 0.003). The range of fluid infusion rates required to maintain DeltaV(PL) and DeltaV(IT) within the critical values (>-15% and <20%, respectively) was wide for short-duration surgery (2-18.5 mL x kg(-1) x h(-1) for a 2 h-surgery), whereas it was narrow for long-duration surgery (5-8 mL x kg(-1) x h(-1) for a 6 h-surgery). CONCLUSIONS: Based on our model, it should be possible to increase the fluid infusion rate without significant interstitial edema for abdominal surgery of <3 h duration. However, our model predicts that restrictive fluid management should be used in abdominal surgery of >6 h duration to avoid excessive interstitial edema.

Comparison of placental transfer of local anesthetics in perfusates with different pH values in a human cotyledon model.

PURPOSE: We aimed to investigate the placental transfer of local anesthetics in perfusates with different pH values, using a dual-perfused human cotyledon model. METHODS: The dual-perfused human cotyledon model was prepared from placentas obtained following cesarean delivery (n = 5). Protein-free solution was perfused through both maternal and fetal arteries. Four amide-type local anesthetics (mepivacaine [Mep]; lidocaine [Lid]; bupivacaine [Bup]; and ropivacaine [Rop]) were added to the maternal perfusate at 1 microg ml(-1). Three conditions were tested (stage 1, maternal pH 7.4, fetal pH 7.4; stage 2, maternal pH 7.4, fetal pH 6.9; and stage 3, maternal pH 6.9, fetal pH 6.9). Venous blood samples were collected from the fetal circuit after stabilization. The fetal vein/maternal artery concentration ratio (F/M ratio) of the local anesthetics was used as an index of placental transfer. The concentration of human chorionic gonadotropin (hCG) in the maternal vein was measured at the end of each stage. RESULTS: The F/M ratios in all stages were in the order of: Mep > Lid > Bup [symbol: see text] Rop. The F/M ratios of Mep were significantly higher than those of the other local anesthetics in all stages. The F/M ratios of Lid were higher than those of Rop in stages 2 and 3. The F/M ratios of Lid and Rop were higher in stage 2 than in stage 3. However, the differences between the F/M ratios in the three stages were not as large as expected from the basic uncharged ([B]) condition and pH gap. The concentration of hCG showed a time-dependent decrease with increasing stage (stage 1, 81.0 +/- 58.9 mIU ml(-1); stage 2, 57.4 +/- 31.8 mIU ml(-1); stage 3, 32.1 +/- 19.7 mIU ml(-1)). CONCLUSION: Our data clearly show that it is the basic uncharged concentration that mainly determines the placental transfer of amide-type local anesthetics with protein-free perfusate. This finding suggests that Rop and Bup can be used more safely than Mep in terms of placental transfer.

The NMDA receptor NR2A subunit regulates proliferation of MKN45 human gastric cancer cells.

The present study investigated proliferation of MKN28 and MKN45 human gastric cancer cells regulated by the N-methyl-d-aspartate (NMDA) receptor subunit. The NMDA receptor antagonist dl-2-amino-5-phosphonovaleric acid (AP5) inhibited proliferation of MKN45 cells, but not MKN28 cells. Of the NMDA subunits such as NR1, NR2 (2A, 2B, 2C, and 2D), and NR3 (3A and 3B), all the NMDA subunit mRNAs except for the NR2B subunit mRNA were expressed in both MKN28 and MKN45 cells. MKN45 cells were characterized by higher expression of the NR2A subunit mRNA and lower expression of the NR1 subunit mRNA, but MKN28 otherwise by higher expression of the NR1 subunit mRNA and lower expression of the NR2A subunit mRNA. MKN45 cell proliferation was also inhibited by silencing the NR2A subunit-targeted gene. For MKN45 cells, AP5 or knocking-down the NR2A subunit increased the proportion of cells in the G(1) phase of cell cycling and decreased the proportion in the S/G(2) phase. The results of the present study, thus, suggest that blockage of NMDA receptors including the NR2A subunit suppresses MKN45 cell proliferation due to cell cycle arrest at the G(1) phase; in other words, the NR2A subunit promotes MKN45 cell proliferation by accelerating cell cycling.

Vagotomy upregulates expression of the N-methyl-D-aspartate receptor NR2D subunit in the stomach.

BACKGROUND: N-methyl-D-aspartate (NMDA) receptor is the major excitatory neurotransmitter receptor in the central nervous system. Recent evidence has pointed to expression of NMDA receptor in peripheral non-neuronal tissues and organs; however, little is known about the expression of the receptor in the stomach. The present study identified what types of NMDA receptor subunits are expressed in the rat stomach and examined whether vagotomy affects their expression. METHODS: To see the expression and distribution of the mRNAs and proteins for the NMDA receptor subunits, real-time reverse transcription-polymerase chain reaction, Western blotting, in situ hybridization, and immunohistochemistry were carried out on rat stomach with and without vagotomy. RESULTS: Of the NMDA receptor subunits, NR1, NR2 (2A, 2B, 2C, 2D), and NR3 (3A, 3B), all NR subunit mRNAs except for the NR2B subunit mRNA were expressed in the intact rat stomach, with huge expression of NR2D mRNA. Expression of NR2D subunit mRNA and protein significantly increased after vagotomy. Increased expression was found in mucosal cells, the myenteric plexus, and the outer membrane of the stomach with vagotomy. CONCLUSIONS: Vagotomy upregulates expression of the NR2D subunit in the stomach and therefore, the NR2D subunit may be implicated in gastric motility.

[Team training for anesthesia-related difficult airway management performed by participation of surgical center nurses and anesthesiologists].

BACKGROUND: Difficult airway management (DAM) is one of the most important issues for anesthesiologists. The DAM practical seminar was held for the purpose of improving skill and ability for decision-making to the anesthesiologist's DAM. METHODS: In clinical setting, perioperative medical team, which consists of anesthesiologists and nurses, has to struggle against difficult airway cases. To improve the ability of team practice for DAM, we started a training program corresponding to difficult airway management which a nurse and the anesthesiologist jointly perform in the Hyogo College of Medicine Hospital Central Operation Center. RESULTS: From September 2005 to September 2006, we held 6 seminars and 18 anesthesiologists and 17 nurses took part in them. The comment after attendance shows that it was very useful. In scenario session, we trained case management according to the routine emergency call system of Hyogo College of Medicine Hospital Central Operation Center. During session, we discovered the defect of the manual corresponding to emergency, and its improvement. CONCLUSIONS: The DAM practical seminar in the hospital is useful not only for perioperative team practice training, but also for improving the emergency call system.