Sanae Matsumoto

Use of the Pentax-AWS in 293 patients with difficult airways.

Background:Several case reports have shown that the Pentax-AWS® (Hoya Corporation, Tokyo, Japan), a new video laryngoscope, is useful in patients with difficult airways. Methods:We assessed the effectiveness of the Pentax-AWS® in two groups. Group 1 included 270 patients in whom direct laryngoscopy using a Macintosh laryngoscope had been difficult. Group 2 included 23 patients with predicted difficult intubation and difficult mask ventilation without previous use of the Macintosh laryngoscope. Results:In group 1, the view of the glottis with the Macintosh laryngoscope was Cormack and Lehane grade 2 in 14 patients, grade 3 in 208 patients, and grade 4 in 48 patients. In 256 patients in whom the grade was 3 or 4 with the Macintosh laryngoscope, the view with the Pentax-AWS® was either grade 1 or 2 in 255 patients (99.6%; 95% confidence intervals 97.8–100%). Tracheal intubation was successful with the Pentax-AWS® in 268 of 270 patients (99.3%; 95% confidence interval 97.4–100%), and it failed (after two attempts) in two patients. In group 2, tracheal intubation was successful in 22 of 23 patients, and it failed in one patient. The reasons for failed intubation using the Pentax-AWS® were failure to position the blade toward the glottic side of the epiglottis, inability to maneuver the endotracheal tube away from the arytenoids and into the trachea, and bleeding and swelling of the oropharynx. Conclusion:The success rate of tracheal intubation using the Pentax-AWS® was high in patients with difficult laryngoscopy with a Macintosh laryngoscope and in patients with predicted difficult intubation.

The effects of the lateral position on cardiopulmonary function during laparoscopic urological surgery

Laparoscopic urological surgery is usually performed transperitoneally with retroperitoneal insufflation of carbon dioxide (CO2) in the lateral position.We studied whether a difference in the side of lateral position affected hemodynamic and pulmonary functions during pneumoperitoneum. Fifteen patients (eight in the right and seven in the left lateral position) undergoing elective laparoscopic urological surgery were studied under general anesthesia. Hemodynamic variables and blood gas data were recorded. Before insufflation, mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP), and pulmonary capillary wedge pressure (PCWP) in the right lateral position were higher than those in the left lateral position. Pneumoperitoneum increased MAP, MPAP, CVP, PCWP, and cardiac index but decreased systemic vascular resistance in the right lateral position. Similar changes occurred during pneumoperitoneum in the left lateral position, but the changes were less than those in the right lateral position. The respiratory index (PaO2/PAO2), intrapulmonary shunt, and SpO2 did not change during pneumoperitoneum in either lateral position. Changing the side of the lateral position affected hemodynamic function but did not affect pulmonary oxygenation during pneumoperitoneum. Implications: The right and left lateral positions produced different hemodynamic changes during laparoscopic urological surgery. The increases in preload and cardiac index and the decrease in systemic vascular resistance were greater in the right than in the left lateral position. Respiratory changes were not affected differently between the right and left lateral positions. (Anesth Analg 1998;87:925-30)

Truview video laryngoscope in patients with difficult airways.

hospital-wide “needleless systems,” injection ports on IV tubing that heretofore could be accessed with needles are now “needleless.” Inserting a needle through these ports frequently lacerates the material within the ports, rendering them incompetent or subject to subsequent leakage. I have adapted our blood collection bags to be compliant with our hospital’s needleless systems initiative. First, the needle and a short segment of adjacent tubing are excised from the distal end of the blood collection bag tubing. Then, maintaining aseptic technique, a standard male-to-male Luer Lock adapter (Mallinckrodt Critical Care, Glens Falls, NY) is attached to the distal end of the tubing. The adapter fits the tubing snugly and provides a secure, stable connection. (Fig. 1B) The other end of the male-to-male Luer Lock adapter may now be attached to the female Luer Lock connector of any needleless port or standard 3-way stopcock. I have found this simple adaptation to be safe, efficient, and inexpensive. It has been successfully used in more than 100 cases without problems related to blood flow into the collection bag or inadvertent disconnections. Although blood banks have more elaborate devices for modifying blood bag tubing, such as tubing welders, these services are typically remote from the operating room environment. In addition, they require advance coordination with the blood bank, which may be time consuming and inconvenient for the busy anesthesiologist.

Prevention of needle-stick injury. Efficacy of a safeguarded intravenous cannula.

One possible method of reducing the incidence of needle‐stick injury is to use needles with safeguard mechanisms. The needle of the Insyte AutoGuard intravenous cannula can be retracted into the safety barrel. One hundred patients were randomly allocated to receive either an 18‐gauge conventional Insyte intravenous cannula (group C) or the AutoGuard cannula (group AG) to assess the ease of use and efficacy of the AutoGuard device. It was possible to insert the cannula into the vein within two attempts in all patients; there was no significant difference between two groups with respect to ease of insertion. No problems, such as inadvertent withdrawal of the needle, occurred during insertion in any patient. Handling the withdrawn needle was judged significantly safer in group AG than in group C (p < 0.001). Blood contamination often occurred where a withdrawn needle was placed in group C, whereas no blood stain was detected in any case in group AG (p < 0.001). The AutoGuard cannula provides safer handling of a withdrawn needle without reducing its ease of insertion.

Use of the laryngeal tube after failed insertion of a laryngeal mask airway

The Laryngeal Tube (VBM, Medizintechnik, Germany) has a potential role during anaesthesia and cardiopulmonary resuscitation [1, 2]. It consists of an airway tube with a small balloon cuff attached at the tip and a larger balloon cuff at the middle part of the tube. We report successful use of the laryngeal tube in three patients in whom insertion of the laryngeal mask airway had failed. An 18-year-old fit and healthy woman (165 cm, 52 kg) was scheduled for left oophorectomy. After epidural catheterisation, general anaesthesia was induced with propofol 100 mg and deepened with sevoflurane. After no motor response to thrusting the jaw forward had been confirmed [3], the mouth was opened to insert a laryngeal mask airway. Enlarged tonsils were found. Because there was a gap between the tonsils (approximately 1.5 cm), we felt that it might be possible to insert the laryngeal mask, but failed to advance the device beyond the tonsils despite using the insertion technique described in the manufacturer’s instruction manual. Insertion of a flexible laryngeal mask (which should be easier to insert in patients with enlarged tonsils) also failed. Before tracheal intubation, we tried a laryngeal tube, which was easily inserted. The lungs were ventilated through the laryngeal tube without complications during the 80 min operation. A 46-year-old woman (159 cm, 55 kg), with a history of Basedow’s disease at 20 years and tonsillectomy at 34 years, was scheduled for left oophorectomy. Preoperative examination indicated a goitre (with normal thyroid function) without deviation of the trachea or difficulty in breathing. After epidural catheterisation, general anaesthesia was induced with propofol 100 mg and maintained with a targetcontrolled infusion. After no motor response to jaw thrusting had been confirmed, insertion of a laryngeal mask airway was attempted, but it was impossible to advance it beyond the back of the throat. In contrast, insertion of a laryngeal tube was easy. The operation (40 min) proceeded without complications. A 72-year-old man (157 cm, 74 kg) was scheduled for right total hip arthroplasty. Preoperatively, difficult tracheal intubation was predicted, because the view of the oropharynx was limited (Mallampati score 3), the thyromental distance was 5 cm, there was a mild difficulty in thrusting the jaw forward and extending the neck, and snoring during sleep. After epidural catheterisation, anaesthesia was induced with propofol 150 mg. Insertion of a laryngeal mask failed twice. In contrast, a laryngeal tube was easily inserted and was used during anaesthesia of 140 min, without complications. The exact reason for successful insertion of the laryngeal tube after failed insertion of the laryngeal mask airway in these cases is not known, but the success and failure might have been related to a difference in the width of these two devices. The pharyngeal space was narrowed by swollen tonsils in case 1, by a goitre in case 2, and possibly by redundant tissues in the pharynx (which produced the snoring) in case 3. Insertion of the laryngeal mask airway might not have been possible because the distal part of the mask had wedged in the narrowed pharynx. The distal segment of the laryngeal tube is not tapered, and the width of the tube is narrower than that of the laryngeal mask airway (Fig. 3), and thus the laryngeal tube might have passed through the narrowed space. We suggest that, when insertion of the laryngeal mask airway is difficult or impossible due to a narrowed pharynx, insertion of the laryngeal tube may be attempted, before considering tracheal intubation.

Use of the McCoy laryngoscope or fingers to facilitate fibrescope-aided tracheal intubation

In fibrescope‐aided tracheal intubation, it can be difficult to advance a tube over a fibrescope, because its passage may be impeded by the epiglottis, arytenoids or pyriform fossa. In two patients with difficult intubation, after successful insertion of a fibrescope into the trachea, it was impossible to advance the tube over the fibrescope. Fibrescope‐aided tracheal intubation was accomplished by shifting the epiglottis anteriorly and ‘opening up’ the glottis either by fingers or the McCoy laryngoscope.

Respiratory effects of CO2 pneumoperitoneum during transperitoneal laparoscopic urological surgery

OBJECTIVE To evaluate the effects of CO2 pneumoperitoneum on respiratory function during urological laparoscopic surgery with exposure of the retroperitoneal space in the lateral decubitus position. METHODS Arterial blood gas analysis and measurements of the partial pressure of CO2 in exhaled gas (PetCO2) were performed during CO2 pneumoperitoneum in 12 patients who underwent transperitoneal laparoscopic surgery for the retroperitoneal organs (the retroperitoneal group): the results were compared to those of 11 patients who underwent laparoscopic varicocelectomy (the varicocele group) with the same anesthesia and intra-abdominal pressure. RESULTS The increase in PaCO2 and PetCO2 and the decrease in arterial pH during CO2 insufflation were significantly greater in the retroperitoneal group than in the varicocele group. PaCO2, PetCO2 and arterial pH continued to change in the retroperitoneal group, whereas these values reached a plateau at 30 min after the beginning of CO2 insufflation in the varicocele group. CONCLUSIONS The respiratory effects of CO2 pneumoperitoneum are more pronounced during laparoscopic urological surgery with opening of the retroperitoneum. It is possible that exposure of the retroperitoneal space increased CO2 absorption during insufflation.

The Pentax-AWS for airway obstruction after tracheal extubation

We report two cases of airway obstruction occurring after tracheal extubation, in which the cause of airway obstruction could immediately be confirmed, and re-intubation carried out, using the Pentax-AWS videolaryngoscope (Pentax, Tokyo, Japan). In the first, a middle-aged woman was scheduled for laparoscopic cholecystectomy. After induction of anaesthesia and neuromuscular blockade, the trachea was intubated. At the end of uneventful operation, 50 mg flurbiprofen axetil, a non-steroidal antiinflammatory drug, was injected intravenously. The trachea was extubated after the patient regained consciousness and responded to verbal command. Shortly later, she complained of dyspnoea and acute airway obstruction occurred. A laryngeal mask airway was inserted while a new tracheal tube was being prepared, but obstruction continued. As rashes had appeared on her chest wall, anaphylactic reaction to the nonsteroidal anti-inflammatory drug was suspected. While treatment was being started for possible anaphylaxis, the laryngeal mask was removed and the Pentax-AWS inserted, to observe the upper airway. Oedema of the glottis was confirmed on the videoscreen. The trachea was re-intubated, by advancing a tracheal tube which was attached to the Pentax-AWS. In the second case, a middle-aged man was scheduled for laryngomicrosurgery. After uneventful induction of anaesthesia and tracheal intubation, the surgeons resected laryngeal tumour without difficulty and reported that there was no oedema or bleeding. The trachea was extubated after the patient had regained consciousness and responded to verbal command. Immediately after this, airway obstruction occurred and arterial haemoglobin oxygen saturation decreased to 70%. Insertion of the Pentax-AWS showed that the supraglottic area was now grossly oedematous. A tracheal tube which was attached to the Pentax-AWS was advanced into the trachea. In both cases, the trachea was extubated uneventually the next day. The shape of the Pentax-AWS blade is based on oropharyngeal anatomy, thus there is no need to place the patient’s head and neck to the ‘sniffing’ position, and little force is required to see the glottis [1, 2]. Consequently, insertion of the Pentax-AWS should be less stressful than with the Macintosh blade in awake patients. The videoscreen of the Pentax-AWS enables one to clearly see the cause of upper airway obstruction. In addition, because a tracheal tube is already attached to Pentax-AWS, it is possible to intubate the trachea immediately after confirming the cause of airway obstruction. We believe that the Pentax-AWS is potentially useful in patients with airway obstruction after tracheal extubation, when there is not enough time to give sedatives or local anaesthetics for insertion of a Macintosh laryngoscope, or to carry out fibreoptic intubation.

A patient with cardiac amyloidosis successfully managed with propofol anesthesia.

The preoperative electrocardiogram (ECG) showed first degree AV block alone; the heart rate was 70– 80 min 1. Ultrasound assessment (UCG) showed a hypertrophied interventricular septum and a normal left ventricular ejection fraction of 68%, but left ventricular diastolic function was decreased on UCG. Pulse Doppler methods of UCG showed that the atrial peak velocity/early peak velocity (A/E) ratio was 1 (0.7) and the deceleration time (DT) was 190ms. These data suggested a pseudonormalization state. Although these data seemed to be normal, the diastolic function of the left ventricle had been progressively damaged. His cardiac symptoms were evaluated as New York Heart Association (NYHA) degree 2. Coronary angiography showed no abnormal findings. Blood chemistry showed slight elevation of blood urea nitrogen (BUN) (25 mgdl 1) and creatinine (1.2mgdl 1), which reflected renal amyloidosis. After premedication with 5mg of diazepam and 150 mg of ranitidine orally 1h before arrival at the operating room, anesthesia was induced with 70 mg of propofol, 100 μg of fentanyl, and 8 mg of vecuronium. Anesthesia was maintained with 4–5 mg·kg 1·h 1 of propofol and intermittent injections of fentanyl and vecuronium. His respiration was supported by ventilation with air and oxygen. Total doses of propofol and fentanyl were 863 mg and 250μg, respectively. In addition to basic monitoring, a cannula was inserted into the right dorsalis pedis artery, and a pulmonary artery (PA) catheter (Edwards Swan-Ganz CCO/ Sv̄O2/VIP Thermodilution Catheter 8 F, Baxter) was inserted in order to evaluate hemodynamic changes during the procedure. Intraoperative changes in hemodynamic variables are shown in Fig. 1. Because the cardiac index (CI), blood pressure, and pulmonary capillary wedge pressure (PCWP) decreased to 1.7 l·min 1·m 2, 78/46 mmHg, and 8mmHg, respectively, although the oxygen saturation in mixed venous blood (Sv̄O2) was within normal range

Changes in plasma catecholamine levels following injection of prostaglandin F2α into the basal cistern in rabbits

We measured plasma epinephrine and norepinephrine concentrations in a rabbit model simulating subarachnoid hemorrhage (SAH), following the injection of prostaglandin F2α (PGF2α) into the basal cistern. In this model, plasma epinephrine values increased significantly (to 4.2-fold those before injection), substantially more than norepinephrine (which increased 1.3-fold) at 5 minutes (min) after PGF2α injection. Dissection of autonomic outflow from the cervical spinal cord or ligation of the suprarenal veins reduced the changes in plasma catecholamine concentrations associated with PGF2α injection. These results suggest that the sympathetic discharge seen after PGF2α injection into the basal cistern in rabbits occurred through the sympatho-adrenal pathways.