Tidal volume and airway pressure under percutaneous transtracheal ventilation without a jet ventilator: comparison of high-flow oxygen ventilation and manual ventilation in complete and incomplete upper airway obstruction models.

PURPOSE: Percutaneous transtracheal ventilation (PTV) can be life-saving in a cannot ventilate, cannot intubate situation. The aim of this study was to investigate the efficacy of PTV by measuring tidal volumes (VTs) and airway pressure (Paw) in high-flow oxygen ventilation and manual ventilation using a model lung. METHODS: We examined 14G, 16G, 18G, and 20G intravenous catheters and minitracheotomy catheters. In high-flow oxygen ventilation, the flow was set to 10 L/min, while the inspiratory:expiratory phases (I:E) were 1 s:4 s in the complete upper airway obstruction model and 1 s:1 s in the incomplete obstruction model. In manual ventilation, I:E were 2 s:4 s in the complete obstruction model and 2 s:3 s in the incomplete obstruction model. We ventilated through each catheter for 2 min and measured VT and Paw. RESULTS: In high-flow ventilation, the average VTs were approximately 150 ml and <100 ml with 14G catheters in complete and incomplete upper airway obstruction, respectively. The VTs obtained were reduced when the bore size was decreased. In manual ventilation, the average VTs were over 300 ml and approximately 260 ml with 14G catheters in complete and incomplete upper airway obstruction, respectively. In high-flow ventilation, the airway pressure tended to be higher. The minitracheotomy catheters produced over 800 ml of VT and created almost no positive end-expiratory pressure. CONCLUSIONS: High-flow ventilation tends to result in higher airway pressure despite a smaller VT, which is probably due to a PEEP effect caused by high flow.

A successful combined spinal-epidural anesthesia for cesarean section in a patient with neurofibromatosis type 1-associated dural ectasia.

BACKGROUND: Dural ectasia is a common manifestation of neurofibromatosis type 1. Although there have been reports of unsuccessful spinal anesthesia due to dual ectasia in Marfan syndrome, reports describing similar unsuccessful spinal anesthesia in neurofibromatosis type 1 are lacking. CASE PRESENTATION: A parturient with neurofibromatosis type 1 was scheduled for a repeat cesarean section. During a previous cesarean section, she had experienced a failed spinal anesthesia, which resulted in a conversion to general anesthesia. Preoperative lumbar magnetic resonance imaging revealed dural ectasia, which was speculated to be the cause of the previous spinal anesthesia failure. Therefore, combined spinal-epidural anesthesia was implemented. Because the block level of spinal anesthesia was insufficient as predicted, supplemental administration of epidural anesthesia successfully provided adequate analgesia for the surgery. CONCLUSIONS: Combined spinal-epidural anesthesia can be useful for the management of cesarean sections in patients with neurofibromatosis type 1-associated dural ectasia.

Quadriplegia after ECMO therapy with sluggish recovery in a COVID-19 patient: A case report with a 14-month follow-up.

COVID-19 patients often develop neuromuscular complications, and critically ill patients often develop ICU-acquired weakness. We report a COVID-19 patient who developed flaccid quadriplegia after ECMO therapy and achieved a slow but consistent recovery during a 14-month period of sustained holistic rehabilitation including early mobilization to an outdoor environment.

Out-of-the-ICU Mobilization in Critically Ill Patients: The Safety of a New Model of Rehabilitation.

OBJECTIVES: Early mobilization of ICU patients has been reported to be safe and feasible. Recently, our ICU implemented out-of-the-ICU wheelchair excursions as a daily rehabilitation practice. The aim of this study is to investigate the safety of participation in the out-of-the-ICU program for early mobilization. DESIGN: Retrospective cohort study. SETTING: Single general ICU in a tertiary teaching hospital. PATIENTS: Adult patients who were admitted to the ICU and underwent the out-of-the-ICU program as an early mobilization intervention was investigated. INTERVENTIONS: The out-of-the-ICU activities include visiting indoor area, visiting our outdoor garden, and bathing. MEASUREMENTS AND MAIN RESULTS: Medical records of ICU patients who participated in the out-of-the-ICU program were reviewed. The primary outcome was the occurrence rate of physical safety events, defined as unintentional removal of medical devices, patient agitation, a fall, or an injury. The secondary outcome was the occurrence rate of adverse physiologic changes, defined as hypotension, hypertension, bradycardia, tachycardia, desaturation, bradypnea, tachypnea, an increase in Fio2, or an increase in doses of vasoactive drugs. In total, 99 adult patients participated in the program, comprising a total of 423 out-of-the-ICU sessions. Among them, one session resulted in a physical safety event, the dislodgement of a tracheostomy tube. In 23 sessions, one or two adverse physiologic changes occurred. None of these events required additional treatment nor resulted in serious sequelae. CONCLUSIONS: An out-of-the-ICU program can be provided safely to adult ICU patients, provided that it is supervised by a dedicated intensivist with an appropriately trained multiprofessional staff and equipment on-site. It appears to contribute to the promotion of humanizing intensive care.

[Case of pseudoankylosis of the mandible after craniotomy].

Craniotomy sometimes causes pseudoankylosis of the mandible, i.e., limited mouth opening, leading to a difficult airway. We describe a case of difficult airway due to pseudoankylosis of the mandible after craniotomy, in which orotracheal intubation was successfully performed with an AirWay Scope (AWS). A 60-year-old woman was scheduled for clipping of an unruptured cerebral aneurysm. She had undergone emergency clipping of a ruptured cerebral aneurysm under frontotemporal craniotomy on the other side three weeks previously. In the previous anesthesia, she had presented normal mouth opening, and orotracheal intubation had been easily performed. Preoperative examination for the second surgery, however, revealed that she had a limited mouth opening with 1.8 cm of interincisor distance, resulting in a class 4 Mallampati view. A difficult airway was anticipated. In order to avoid the risk of hypertension caused by sedated-awake fiberoptic intubation, we planned orotracheal intubation under general anesthesia with AWS. After careful induction with fentanyl and propofol, the blade was inserted smoothly. Her glottic opening was easily visualized, and her trachea was intubated without any difficulty or any distinct hemodynamic disturbance. Careful assessment of the interincisor distance is essential in patients who have previously undergone craniotomy.

A novel skin-traction method is effective for real-time ultrasound-guided internal jugular vein catheterization in infants and neonates weighing less than 5 kilograms.

BACKGROUND: Internal jugular vein (IJV) catheterization in pediatric patients is sometimes difficult because of the small sizes of veins and their collapse during catheterization. To facilitate IJV catheterization, we developed a novel skin-traction method (STM), in which the point of puncture of the skin over the IJV is stretched upward with tape during catheterization. In this study, we examined whether the STM increases the cross-sectional area of the vein and thus facilitates catheterization. METHODS: This was a prospective study conducted from December 2006 to June 2008. We enrolled 28 consecutive infants and neonates weighing <5 kg who underwent surgery for congenital heart disease. The patients were randomly assigned to a group in which STM was performed (STM group) or a group in which it was not performed (non-STM group). The cross-sectional area and diameter of the right IJV in the flat position and 10 degrees Trendelenburg position with and without applying STM were measured. We determined time from first skin puncture to the following: (a) first blood back flow, (b) insertion of guidewire, and (c) insertion of catheter. Number of punctures, success rate, complications, and degree of IJV collapse during advancement of the needle (estimated as decrease of anteroposterior diameter during advancement of the needle compared with the diameter before advancement) were also examined. RESULTS: STM significantly increased the cross-sectional area and the anteroposterior diameter of the IJV in both positions. The time required to insert the catheter was significantly shorter in the STM group, probably mainly due to a shorter guidewire insertion time. The degree of IJV collapse during advancement of the needle was much lower in the STM group. CONCLUSIONS: STM facilitates IJV catheterization in infants and neonates weighing <5 kg by enlarging the IJV and preventing vein collapse.

Severe hyponatremia occurring after surgical stress in a patient with mitochondrial disease.

A 53-year-old man with mitochondrial disease underwent gastrectomy because of gastric cancer. Three days after the surgery, he developed severe hyponatremia (Na, 106 mmol l(-1)) together with hypovolemic shock and lactic acidosis. Despite the hyponatremia, his urine sodium concentration was high, suggesting renal salt wasting. Although mitochondrial diseases are not common and hyponatremia in patients with these diseases is not well known, clinicians should pay close attention to serum sodium levels and maintain them properly.

Time progression from the patient's operating room entrance to incision: factors affecting anesthetic setup and surgical preparation times.

PURPOSE: Owing to recent advances in surgical technology, substantial time is required for preparing surgical equipment before incision. The purpose of this study was to demonstrate the time progression from a patient's operating room entrance to incision and to evaluate the duration of each anesthetic procedure and surgical preparation. METHODS: We marked the following seven points on the anesthetic chart: (1) entrance; (2) i.v. line placement; (3) preoxygenation; (4) intubation; (5) completion of patient positioning (Anesth-Set); (6) applying antiseptic solution; and (7) incision. Afterward, we analyzed the event time periods according to anesthetic procedure, patient position, surgical service, and surgical procedure (such as the utilization of endoscopy, navigation systems, and sentinel lymph node biopsy). RESULTS: On average, it took approximately 3 min to start i.v. placement, 7 min until preoxygenation, 15 min until intubation, and 30 min until Anesth-Set. Epidural, arterial, and central venous catheterization required 15, 9, and 13 min, respectively. It took 20 min from Anesth-Set to incision, on average; 22, 4, and 5 min were required to prepare the navigation system, endoscope, and sentinel lymph node biopsy, respectively. In total, it took an average of 49.8 +/- 17.1 min from entrance to incision, which was significantly longer (30.4 +/- 8.8 min) than it took in 1985-1986. CONCLUSION: The mean time taken from the patient's operating room entrance to incision is now significantly longer than before. This may be attributed, at least in part, to the preparation of equipment associated with new surgical technologies.

Before-after study of a restricted fluid infusion strategy for management of donor hepatectomy for living-donor liver transplantation.

PURPOSE: Intraoperative fluid infusion strategy remains controversial. Many animal model studies have shown that restricted fluid infusion reduces blood loss, though reports on this topic in humans are rare. The purpose of this study was to determine the effects on volume of blood loss of a restricted fluid infusion strategy for hepatectomy in donors for living donor liver transplantation. METHODS: A before-after study design was used with prospective consecutive data collection. A total of 22 patients who underwent living-donor hepatectomy were enrolled. Eleven patients who were managed before the implementation of restricted-volume fluid administration comprised the standard-volume group, and 11 who were evaluated after the implementation of the restricted-volume infusion strategy comprised the restricted-volume group. In the standard-volume group, the donors were given 10 ml x kg(-1) x h(-1) of lactated Ringer's solution and additional plasma expander corresponding to blood loss. In the restricted-volume group, the donors received 5 ml x kg(-1) x h(-1) of lactated Ringer's solution until the resection of the hepatic graft, followed by 15 ml x kg(-1) x h(-1) of lactated Ringer's solution after the completion of resection until the end of the operation. RESULTS: Intraoperative blood loss was less in the restricted-volume group (445 +/- 193 ml) than in the standard-volume group (1331 +/- 602 ml; P < 0.01). Intraoperative fluid infusion was also less in the restricted-volume group (4130 +/- 563 ml) than in the standard-volume group (5634 +/- 1260 ml; P < 0.01). There were no differences in length of hospital stay or side effects between the two groups. CONCLUSION: Our restricted-volume strategy reduced blood loss and had no adverse effects during living-donor hepatectomy.

A simple, lightweight CPAP-delivery device, composed of a three-way stopcock, for the nondependent lung.

PURPOSE: We aimed to introduce a simple, lightweight continuous positive airway pressure (CPAP)-delivery device for the nondependent lung during one-lung ventilation, to investigate how the type of three-way stopcocks, and the compliance and resistance of a test lung affect the relationship between the oxygen flow rate and CPAP level produced, and to examine how the device works in a clinical setting. METHODS: In the test lung study, the bronchial blocker of a Univent tube was connected to a test lung. The effects of oxygen-flow rate, types of three-way stopcocks, and compliance and resistance of the test lung on the CPAP levels were studied. In the clinical study, the lightweight device was used to treat hypoxia in seven patients during one-lung ventilation with the bronchial blocker. RESULTS: In the test lung study, the CPAP level produced by the device was proportional to the oxygen-flow rate, dependent on the type of three-way stopcock used, and independent of the compliance or resistance of the test lung. There was no discrepancy between the plateau pressures of the test lung and the monitoring port of an additional stopcock at any degree of compliance or resistance of the test lung at any oxygen-flow rate. Therefore, the relationship between the oxygen-flow rate and CPAP level can be ensured in advance before application to the lung, with an additional three-way stopcock of which the distal end is occluded. In the clinical study, peripheral oxygen sataration Sp(O2) improved while the CPAP level ranged from 2.8 to 5.4 cmH2O. CONCLUSION: The lightweight CPAP delivery-device can provide variable CPAP levels by adjusting the oxygen-flow rate without real-time monitoring of the pressure.

Skin-traction method prevents the collapse of the internal jugular vein caused by an ultrasound probe in real-time ultrasound-assisted guidance.

PURPOSE: Real-time ultrasound-assisted guidance for catheterization of the internal jugular vein (IJV) is known to be useful, especially for a small-sized vein, which is difficult to catheterize. However, one of the problems with real-time ultrasound-assisted guidance is that the ultrasound probe itself can collapse the vein. We have developed a novel "skintraction method (STM)", in which the puncture point of the skin over the IJV is stretched upwards with several pieces of surgical tape in the cephalad and caudal directions with the aim being to facilitate catheterization of the IJV. We examined whether this method increased the compressive force required to collapse the IJV. METHODS: In ten volunteers, the compressive force required to collapse the right IJV, and the cross-sectional area and anteroposterior and transverse diameters of the IJV were measured with ultrasound imaging in the supine position (SP) with or without the STM or in the Trendelenburg position of 10 degrees head-down (TP) without the STM. RESULTS: The compressive force to required to collapse the vein was increased significantly with the STM, while the crosssectional area and anteroposterior diameter of the vein in the SP with STM were similar to those in the TP without the STM. CONCLUSION: With the STM, not only the cross-sectional area but also the compressive force required to collapse the IJV increased. Thus, the STM may facilitate real-time ultrasoundassisted guidance for catheterization of the IJV by maintaining the cross-sectional area of the vein during the guidance.

Modified N95 mask delivers high inspired oxygen concentrations while effectively filtering aerosolized microparticles.

STUDY OBJECTIVE: In a pandemic, hypoxic patients will require an effective oxygen (O2) delivery mask that protects them from inhaling aerosolized particles produced by others, as well as protecting the health care provider from exposure from the patient. We modified an existing N95 mask to optimize O2 supplementation while maintaining respiratory isolation. METHODS: An N95 mask was modified to deliver O2 by inserting a plastic manifold consisting of a 1-way inspiratory valve, an O2 inlet and a gas reservoir. In a prospective repeated-measures study, we studied 10 healthy volunteers in each of 3 phases, investigating (1) the fractional inspiratory concentrations of O2 (F(I)O2) delivered by the N95 O2 mask, the Hi-Ox80 O2 mask, and the nonrebreathing mask during resting ventilation and hyperventilation, each at 3 O2 flow rates; (2) the ability of the N95 mask, the N95 O2 mask, and the nonrebreathing mask to filter microparticles from ambient air; and (3) to contain microparticles generated inside the mask. RESULTS: The F(I)O2s (median [range]) delivered by the Hi-Ox80 O2 mask, the N95 O2 mask, and the nonrebreathing mask during resting ventilation, at 8 L/minute O2 flow, were 0.90 (0.79 to 0.96), 0.68 (0.60 to 0.85), and 0.59 (0.52 to 0.68), respectively. During hyperventilation, the FiO2s of all 3 masks were clinically equivalent. The N95 O2 mask, but not the nonrebreathing mask, provided the same efficiency of filtration of internal and external particles as the original N95, regardless of O2 flow into the mask. CONCLUSION: An N95 mask can be modified to administer a clinically equivalent FiO2 to a nonrebreathing mask while maintaining its filtration and isolation capabilities.

Orotracheal intubation with an AirWay Scope in a patient with Treacher Collins syndrome.

Treacher Collins syndrome (TCS) is a congenital malformation of craniofacial development; in these patients conventional direct laryngoscopy is very difficult and often unsuccessful because of the upper airway malformation. A 20-year-old man with TCS was scheduled for elective tympanoplasty. The patient showed the characteristic facial appearance of TCS, and a difficult airway was anticipated. After careful anesthesia induction, direct laryngoscopy with Macintosh blade no. 4 of a direct laryngoscope failed to visualize the epiglottis, even with cricoid pressure, resulting in a grade 4 Cormack and Lehane view. Next, the AirWay Scope was easily inserted, and his glottic opening was clearly visualized. An 8.0-mm-internal-diameter tracheal tube was then advanced into the trachea without any difficulty. The AirWay Scope is a very useful airway device for orotracheal intubation; it provides an excellent view of the glottis without requiring alignment of the oral, pharyngeal, and laryngeal axes, and appears to be promising for use in patients with a difficult airway.

The skin-traction method increases the cross-sectional area of the internal jugular vein by increasing its anteroposterior diameter.

PURPOSE: We developed a novel "skin-traction method" in which the puncture point of the skin over the internal jugular vein (IJV) is stretched upward with several pieces of surgical tape in the cephalad and caudad directions to facilitate cannulation of the IJV. We investigated whether this method increases the cross-sectional area of the IJV. METHODS: In 11 healthy volunteers, the cross-sectional area, anteroposterior diameter, and transverse diameter of the right IJV (RIJV) were recorded by ultrasound echo at head tilts of +10 degrees , +5 degrees , 0 degrees , -5 degrees , and -10 degrees with and without the skin-traction method. RESULTS: The skin-traction method significantly increased the cross-sectional areas of the RIJV at head tilts of +10 degrees , +5 degrees , and 0 degrees . In the flat position, the skin-traction method increased the cross-sectional area of the RIJV from 1.21 +/- 0.44 cm(2) to 1.75 +/- 0.60 cm(2) (44.6% increase), which is almost the same as that in the Trendelenburg position without this method (1.60 +/- 0.54 cm(2) at -5 degrees and 1.83 +/- 0.56 cm(2) at -10 degrees ). The anteroposterior diameter of the RIJV was significantly increased in all positions with this method, although the transverse diameter was not. CONCLUSION: This method significantly increased the cross-sectional area of the RIJV by increasing the anteroposterior diameter of the RIJV. Even in the flat position, this method was almost as efficacious as the Trendelenburg position. This method thus appears to facilitate IJV cannulation.

Anesthetic management of a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) during laparotomy.

A 53-year-old man with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) underwent a gastrectomy. We administered bicarbonated Ringer's solution, which has a physiological concentration of bicarbonate. The level of serum lactate did not increase significantly, and metabolic acidosis did not occur throughout surgery or for 3 h after surgery. Aggressive warming was needed to maintain normothermia, presumably because the mitochondrial respiratory chain, which is responsible for thermogenesis, is impaired in MELAS patients. It is important to maintain normothermia in MELAS patients in order to avoid further mitochondrial metabolic depression.

Vagal nerve activity contributes to improve the efficiency of pulmonary gas exchange in hypoxic humans.

The aim of this study was to test our hypothesis that both phasic cardiac vagal activity and tonic pulmonary vagal activity, estimated as respiratory sinus arrhythmia (RSA) and anatomical dead space volume, respectively, contribute to improve the efficiency of pulmonary gas exchange in humans. We examined the effect of blocking vagal nerve activity with atropine on pulmonary gas exchange. Ten healthy volunteers inhaled hypoxic gas with constant tidal volume and respiratory frequency through a respiratory circuit with a respiratory analyser. Arterial partial pressure of O(2) (P(aO(2))) and arterial oxygen saturation (S(pO(2))) were measured, and alveolar-to-arterial P(O(2)) difference (D(A-aO(2))) was calculated. Anatomical dead space (V(D,an)), alveolar dead space (V(D,alv)) and the ratio of physiological dead space to tidal volume (V(D,phys)/V(T)) were measured. Electrocardiogram was recorded, and the amplitude of R-R interval variability in the high-frequency component (RRIHF) was utilized as an index of RSA magnitude. These parameters of pulmonary function were measured before and after administration of atropine (0.02 mg kg(-1)). Decreased RRIHF (P < 0.01) was accompanied by decreases in P(aO(2)) and S(pO(2)) (P < 0.05 and P < 0.01, respectively) and an increase in D(A-aO(2)) (P < 0.05). Anatomical dead space, V(D,alv) and V(D,phys)/V(T) increased (P < 0.01, P < 0.05 and P < 0.01, respectively) after atropine administration. The blockade of the vagal nerve with atropine resulted in an increase in V(D,an) and V(D,alv) and a deterioration of pulmonary oxygenation, accompanied by attenuation of RSA. Our findings suggest that both phasic cardiac and tonic pulmonary vagal nerve activity contribute to improve the efficiency of pulmonary gas exchange in hypoxic conscious humans.

A case of complex regional pain syndrome type II after transradial coronary intervention.

The transradial approach for coronary catheterization is now a routine technique without serious complications at the puncture site. We report a case of complex regional pain syndrome type II (CRPS type II) in the hand after the transradial coronary intervention, which may alert medical personnel that the technique may cause serious regional pain with disability. A 61-year-old woman underwent coronary intervention via the right radial artery for the treatment of unstable angina. After the operation she complained of severe pain in the right hand, consistently felt along the median nerve distribution. The nerve conduction study suggested carpal tunnel syndrome. We made a diagnosis of CRPS type II, and the patient received stellate ganglion blockade, cervical epidural blockade, and administration of amitriptyline and loxoprofen. The symptoms gradually improved and her activities of daily living markedly improved. The median nerve appeared to be damaged by local compression and potential ischemia. Careful attention should be paid to avoid CRPS type II, associated with excess compression.

Cerebral fat embolism diagnosed by magnetic resonance imaging at one, eight, and 50 days after hip arthroplasty: a case report.

PURPOSE: To describe cardiovascular collapse during a cemented hip hemiarthroplasty in a patient who, despite a successful cardiopulmonary resuscitation, remained in a persistent vegetative state due to cerebral fat embolism diagnosed by magnetic resonance imaging (MRI). CLINICAL FEATURES: A 75-yr-old woman with no medical history underwent cemented hip hemiarthroplasty under spinal anesthesia for a right femoral neck fracture. Shortly after insertion of the prosthesis, a sudden oxygen desaturation, hypotension, bradycardia, and cardiac arrest occurred. The patient was successfully resuscitated, but did not regain consciousness. The patient developed high-grade fever, thrombocytopenia, anemia, and oliguria. MRI scans of the brain revealed multiple high intensity signals throughout the white matter, the basal ganglia, the cerebellum, and the brain stem. The diagnosis of fat embolism was made on the basis of clinical findings and MRI images. Although her cardiorespiratory status improved over the next week, the patient remained in a persistent vegetative state. CONCLUSION: When fat embolism is suspected, serial MRI scans of the brain should be performed to diagnose the etiology of cerebral embolism as well as to evaluate the severity of brain damage.

The effects of carbon monoxide on respiratory chemoreflexes in humans.

As protection against low-oxygen and high-carbon-dioxide environments, the respiratory chemoreceptors reflexly increase breathing. Since CO is also frequently present in such environments, it is important to know whether CO affects the respiratory chemoreflexes responsiveness. Although the peripheral chemoreceptors fail to detect hypoxia produced by CO poisoning, whether CO affects the respiratory chemoreflex responsiveness to carbon dioxide is unknown. The responsiveness of 10 healthy male volunteers were assessed before and after inhalation of approximately 1200 ppm CO in air using two iso-oxic rebreathing tests; hypoxic, to emphasize the peripheral chemoreflex, and hyperoxic, to emphasize the central chemoreflex. Although mean (SEM) COHb values of 10.2 (0.2)% were achieved, no statistically significant effects of CO were observed. The average differences between pre- and post-CO values for ventilation response threshold and sensitivity were -0.5 (0.9) mmHg and 0.8 (0.3) L/min/mmHg, respectively, for hyperoxia, and 0.7 (1.1) mmHg and 1.2 (0.8) L/min/mmHg, respectively, for hypoxia. The 95% confidence intervals for the effect of CO were small. We conclude that environments with low levels of CO do not have a clinically significant effect acutely on either the central or the peripheral chemoreflex responsiveness to carbon dioxide.