The Effects of Endotracheal Tube and i-gel® Supraglottic Airway Device on Respiratory Impedance: A Prospective Observational Study.

BACKGROUND: The forced oscillation technique (FOT) is a non-invasive means of measuring respiratory resistance and reactance. We tested our hypothesis that endotracheal intubation would cause more substantial preoperative increases in FOT parameters than a supraglottic airway device (SGD). METHODS: Forty patients requiring general anesthesia and mechanical ventilation for transurethral bladder tumor resection underwent spirometry the day before surgery. Forced oscillation was measured using a MostGraph-01 device the day before surgery and immediately after removal of the airway adjunct. Changes in respiratory resistance and reactance were compared between those intubated and those who used SGD. RESULTS: The trachea was intubated in 23 patients and SGD was used in the remaining 17 patients. Both airway adjuncts caused significant increases in preoperative respiratory resistance and reactance; however, the magnitude of the changes was significantly greater in the intubated patients. CONCLUSIONS: The SGD appears to cause less pulmonary injury than tracheal intubation. Further study is needed to illuminate the influence of mechanical ventilation, and longer-term consequences and clinical significance of the changes we found in this study. Spontaneous ventilation through an SGD may be preferable in patients with severe respiratory disease.

Perioperative evaluation of respiratory impedance using the forced oscillation technique: a prospective observational study.

BACKGROUND: Intravascular fluid shifts, mechanical ventilation and inhalational anesthetic drugs may contribute to intraoperative lung injury. This prospective observational study measured the changes in respiratory impedance resulting from inhalational anesthesia and mechanical ventilation in adults undergoing transurethral resection of bladder tumors. The components of respiratory impedance (resistance and reactance) were measured using the forced oscillation technique (FOT). METHODS: Respiratory resistance at 5 Hz (R5) and 20 Hz (R20), respiratory reactance at 5 Hz (X5), resonant frequency (Fres) and area of low reactance (ALX) were measured before and immediately after surgery in 30 adults. In addition, preoperative vital capacity (VC), forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1.0) were evaluated using spirometry. All patients were intubated with an endotracheal tube and were mechanically ventilated, with anesthesia maintained with sevoflurane. Pre- and postoperative FOT measurements were compared using Wilcoxon paired rank tests, and the relationships between FOT measurements and preoperative spirometry findings were determined by Spearman's rank correlation analysis. RESULTS: Twenty-six patients were included in the final analysis: postoperative FOT could not be performed in four because of postoperative restlessness or nausea. The mean duration of surgery was 47 min. All components of respiratory resistance deteriorated significantly over the course of surgery, with median increases in R5, R20, and R5-R20 of 1.67 cmH2O/L/s (p < 0.0001), 1.28 cmH2O/L/s (p < 0.0001) and 0.46 cmH2O/L/s (p = 0.0004), respectively. The components of respiratory reactance also deteriorated significantly, with X5 decreasing 1.7 cmH2O/L/s (p < 0.0001), Fres increasing 5.57 Hz (p < 0.0001) and ALX increasing 10.51 cmH2O/L/s (p < 0.0001). There were statistically significant and directly proportional relationships between pre- and postoperative X5 and %VC, %FEV1.0 and %FVC, with inverse relationships between pre- and postoperative Fres and ALX. CONCLUSIONS: All components measured by FOT deteriorated significantly after a relatively short period of general anesthesia and mechanical ventilation. All components of resistance increased. Of the reactance components, X5 decreased and Fres and ALX increased. Pre- and postoperative respiratory reactance correlated with parameters measured by spirometry. TRIAL REGISTRATION: JMA-IIA00136 .

[The Effects of Tracheal Suction on Respiratory Impedance].

BACKGROUND: Tracheal suctioning is performed just before extubation to remove sputum from the trachea. Although it is an invasive procedure, its adverse effect on the airway has not been investigated because this is difficult to achieve using conventional tests or monitoring. We performed a study using the forced oscillation technique to investigate whether tracheal suctioning affects respiratory impedance (consisting of respiratory resistance and respiratory reactance). METHODS: This prospective observational study was conducted in 43 patients undergoing transurethral resection of bladder tumors under general anesthesia. Respiratory impedance (R5, R20, and X5) was measured the day before surgery and just after surgery. R5 and R20 are representative values of respiratory resistance, while X5 is representative of respiratory reactance. Participants were divided into two groups: those with or without tracheal suctioning. RESULTS: There were no significant differences in patient backgrounds or preoperative respiratory impedance parameters. In the suctioning group, post- operative R5 and R20 were significantly higher than in the non-suctioning group (P=0.002 and 0.063, respec- tively). There was no significant difference in postop- erative X5 between the two groups. CONCLUSIONS: Tracheal suctioning caused an increase in respiratory resistance in this cohort of patients, sug- gesting that unnecessary suctioning should be avoided during surgery.

[Comparison of the Intracuff Pressure Increase by Upper Gastrointestinal Endoscope Insertion in TaperGuard Cuffed Tube and High-volume Low Pressure Cuffed Tracheal Tube: A Porcine Larynx Model Study].

BACKGROUND: The purpose of this study was to compare the upper gastrointestinal endoscope (UGE) insertion-mediated cuff pressure increase between a tracheal tube with a tapered cuff (Taper) and or conventional high volume low pressure cuff (HVLP) utilizing a porcine larynx model. METHODS: The automated cuff pressure was adjusted to 10, 20, and 30 cmH2O. The Taper and HVLP cuff pressure increases by UGE insertion were measured. RESULTS: Significant cuff pressure increase was observed by UGE insertion regardless of initial cuff pressure. The cuff pressure of the Taper was significantly lower than that of the HVLP by UGE insertion. CONCLUSIONS: These findings suggest that the Taper may be more effective than the HVLP in preventing tracheal tube cuff increase by UGE insertion.

Effect of differences in extubation timing on postoperative care following abdominal aortic replacement surgery: a comparison study.

BACKGROUND: Abdominal aortic replacement requires an extensive incision and strict blood pressure control, making rapid extubation of the tracheal tube and pain management difficult. The effects of extubation timing on the postoperative course and medical costs in the intensive care unit (ICU) were analyzed. METHODS: Patients who underwent elective abdominal aortic replacement were evaluated retrospectively. Patients were divided into those extubated on the day of surgery (Group A) and those extubated later (Group B). Group A was subdivided into extubation in the operating room (Group A1) or in the ICU (Group A2). Intubation time in the ICU, postoperative ICU stay, hospital stay, and total ICU expenses were compared among the four groups. RESULTS: Of the 191 patients, 95 were extubated on the day of surgery (Group A) and 96 later (Group B). The two groups differed in age and percutaneous coronary intervention history. Surgery and anesthesia durations, intraoperative infusion volume, and intraoperative bleeding amounts differed significantly in the two groups. Epidural anesthesia was given more frequently in Group A. Mean intubation time in the ICU (2.6 ± 2.8 vs 17.4 ± 5.1 hours, P < 0.01), the ICU stay (2.1 ± 0.3 vs 2.4 ± 0.8 days, P < 0.01), and the hospital stay (16.4 ± 5.2 vs 20.2 ± 12.5 days, P = 0.02) were significantly shorter, and total ICU expenses were significantly lower (1,036 ± 307 vs 1,565 ± 1,072 dollars, P < 0.01), in Group A than in Group B. Of the 95 patients in Group A, 34 were extubated in the operating room (Group A1) and 61 in the ICU (Group A2). Arrhythmia, epidural anesthesia, and the amount of intraoperative infusion amount were significantly higher, and the percentage of women significantly lower, in Group A1 (vs Group A2). Postoperative ICU and hospital stays and the ICU costs were not significantly different. CONCLUSION: Tracheal tube extubation on the day of abdominal aortic replacement surgery resulted in better postoperative course and lower costs than when extubation occurred later. Patients extubated in the operating room or the ICU on the day of surgery had similar postoperative courses and costs.

A Perioperative Evaluation of Respiratory Mechanics Using the Forced Oscillation Technique.

BACKGROUND: The forced oscillation technique is a new approach for assessing perioperative respiratory function. METHODS: This study enrolled 40 patients undergoing general anesthesia: 20 for ≥2 hours and 20 for <2 hours. Respiratory parameters were measured the day before and after surgery using forced oscillation during normal tidal breathing. RESULTS: Respiratory resistance at 5 Hz (P = 0.029 with the Student t test with unequal variances and P = 0.033 with analysis of covariance) changed significantly in the patients who underwent procedures for which they were anesthetized for >2 hours. CONCLUSIONS: The forced oscillation technique is a clinical tool that can be used to assess the effects of perioperative ventilation strategies on respiratory mechanics.

[Anesthetic Management of One-stage Intravenous Leiomyomatosis Resection Extending to the Right Ventricle].

We report a case of 71-year-old female with intravenous leiomyomatosis (IVL) extending to the right ventricle. She was operated on successfully by one-stage approach involving thoracotomy and laparotomy. The important question was whether to perform IVL extraction first, or hysterectomy first; performing hysterectomy before IVL extraction may increase the risk of postoperative infection such as mediastinitis, as well as the risk of intraperitoneal hemorrhage during cardiopulmonary bypass (CPB) and tumor embolism. On the other hand, if IVL extraction is performed first, there is a possibility of bleeding during hysterectomy following CPB. Moreover, in a case of malignant disease, CPB might increase the risk of systemic metastasis. In the present case, IVL extraction was performed first, considering that hysterectomy before IVL extraction would increase the risk of intraoperative complications, and leading to a successful surgery without any problems. In rare cases, such as this one, it is important that surgeons and anesthesiologists recognize the importance of cooperation and careful surgical planning to decrease the perioperative risks.

[Awake intubation with landiolol and dexmedetomidine in a patient with anxiety neurosis].

We report a successful case of awake intubation in a patient with anxiety neurosis via continuous administration of landiolol and dexmedetomidine. A 52-year-old woman weighing 46.8 kg with anxiety neurosis experienced postoperative bleeding after left-side thyroidectomy and was scheduled for emergent hemostasis under general anesthesia Due to swelling of the neck, we anticipated a difficult airway and decided to perform awake intubation. She showed extreme insecurity and shivering, and initially did not agree to the procedure. To calm her anxiety and panic, we continuously administered 10 microg x kg(-1). min(-1) landiolol and 1.0 microg x kg(-1) hr(-1) dexmedetomidine. After 10 minutes, her shivering disappeared, and she agreed to undergo awake intubation, which was performed with the Pentax-AWS Airwayscope and thin Intlock blade. The patient bucked slightly during intubation but hemodynamic changes were minimal.

[Discrepancy in the length of smoking cessation between surgeon's and anesthesiologist's records in relation to hypoxia during one-lung ventilation].

BACKGROUND: Smoking cessation before pulmonary surgery is essential for preventing respiratory complications associated with operation and anesthesia. We compared patients' smoking habits and length of smoking cessation based on respiratory surgeon's and anesthesiologist's records. METHODS: We retrospectively surveyed 68 patients who underwent elective operation under one-lung ventilation (OLV) with respect to the Brinkmann index, smoking cessation period, and incidence of hypoxia during OLV. RESULTS: Of the 68 patients, 38 had a history of smoking, with no difference in the Brinkmann index according to respiratory surgeons and anesthesiologists. Of the 38 patients, 6 had inconsistent records regarding the length of smoking cessation. The smoking cessation period was significantly longer according to respiratory surgeons (17.5 days (median)) compared to that according to anesthesiologists [2.0 days (median), P < 0.05). The incidence of hypoxia (SP(O2) < 90%) was significantly higher in these patients (4 of 6), relative to those with no discrepancy (2 of 32, P < 0.05). CONCLUSIONS: Accurate information regarding the length of smoking cessation before surgery is difficult to obtain. The incidence of hypoxia during OLV was significantly higher in patients with a discrepancy regarding the length of smoking cessation between respiratory surgeon's and anesthesiologist's records.

[One-lung ventilation with a spiral-tipped double lumen tube for total pneumonectomy with resection of the tracheal bifurcation].

We report a case of successful one-lung ventilation with a spiral-tipped double lumen tube for resection and reconstruction of the tracheal bifurcation. A 71-year-old woman with lung cancer developed its invasion to the right bronchus near the tracheal bifurcation. Right lung total pneumonectomy or reconstruction with resection of the tracheal bifurcation was planned. In order to secure the tracheal tube and cuff around the tracheal bifurcation non-surgically, we first inserted air-Q while confirming the distorted anatomy around the bifurcation. She then underwent left bronchial intubation with a short-cuffed, long-length spiral tracheal tube under bronchofiberscopy, but effective ventilation was not achieved. The tracheal tube was exchanged with a spiral-tipped double lumen tube under bronchofiberscopy and one-lung ventilation was achieved. Total pneumonectomy and reconstruction of the tracheal bifurcation proceeded uneventfully. One-lung ventilation with a spiral-tipped double lumen tube may be useful in tumor resection that involves distorted anatomy, such as at tracheal bifurcation.

[Awake insertion of i-gel under dexmedetomidine sedation in a patient with severe obstructive sleep apnea syndrome].

We report a successful awake insertion of the i-gel supraglottic airway device under dexmedetomidine (DEX) sedation in a patient with severe obstructive sleep apnea syndrome and symptomatic angina. A 71-year-old man was scheduled for open stoma closure under general anesthesia. Given the patient's history of difficult mask ventilation during anesthesia for resection of rectal cancer, we decided to perform awake i-gel insertion under DEX sedation and regional anesthesia with lidocaine. The i-gel was inserted successfully with no vital sign change or vomiting. We also performed transversus abdominis plane block and rectus sheath block with ropivacaine, as severe respiratory suppression due to continuous intravenous fentanyl infusion had been observed in the previous operation. No vital sign change or respiratory suppression was noted upon recovery from general anesthesia. Awake insertion of a supraglottic airway device, such as i-gel, under DEX sedation can be effective for airway management in patients with severe obstructive sleep apnea syndrome.

[Successful double-lumen tube intubation with the Pentax-AWS Airwayscope and a tracheal tube introducer in the lateral position for a patient with a giant mediastinal tumor].

Anesthetic management of a patient with giant mediastinal tumors is challenging from the perspective of both cardiovascular and respiratory management. We report the successful use of the Pentax-AWS Airwayscope (AWS; Hoya, Japan) and a tracheal tube introducer in the left lateral position for a patient with a giant mediastinal tumor. An 18-year-old man weighing 62 kg was scheduled for resection of a giant mediastinal tumor. He suffered from slight dyspnea in the supine position, and slept in the left lateral position. Preoperative chest X-P and computed tomography revealed compression of the left bronchus, heart and aorta. To avoid cardiac and respiratory collapse, anesthesia was induced in the left lateral position without a muscle relaxant. The patient was administered fentanyl 200 microg and propofol 150 mg; mask ventilation with the two-hand technique in the lateral position was successful. Subsequently, the AWS was inserted into his mouth and a 10 Fr tracheal tube introducer was placed in the trachea under the guidance of the AWS monitor. The patient was then intubated with a 35 Fr right-sided double-lumen tracheal tube under the guidance of the tracheal tube introducer. The head of the double-lumen tube was placed in the right bronchus under the guidance of a bronchofiberscope. Following tracheal tube placement, posture was shifted from the left lateral position to supine position without affecting vital signs. After median sternotomy, a muscle relaxant was administered for immobilization.

[Anesthetic management of laser surgery using PCPS for tracheal tumor].

Primary tracheal cancer is extremely rare, but critical tracheal stenosis is seen in many cases. Although laser resection or stent placement is performed under general anesthesia, anesthetic management for tracheal tumor is extremely difficult in terms of airway management. We report a 65-year-old woman scheduled to undergo bronchoscopic laser surgery and insertion of Dumon stent for tracheal tumor which severely obstructed the upper airway. Anesthesia was maintained with propofol, fentanyl and dexmedetomidine. Percutaneous cardiopulmonary support (PCPS) was established via the femoral artery and vein prior to induction of anaesthesia. Tumor resection was performed, but the stent placement was cancelled because a rigid bronchoscope could not be inserted due to difficult laryngeal exposure. Tracheostomy was then performed after weaning from PCPS. Although desaturation due to unsuccessful venous drainage and difficult ventilation by laryngeal edema during the operation and tracheal obstruction by a clot after the operation was observed, the patient's clinical condition improved. In cases of severe tracheal stenosis, airway obstruction by hemorrhage, secretion and laryngeal edema, etc. occur easily. Therefore, some kind of measures should be taken for the operation and a number of precautions must be taken during the perioperative period.