Continuous Oxygen Insufflation Research Articles

Case report: change of dominant strain during dual SARS-CoV-2 infection

BackgroundThe dual infection with SARS-CoV-2 is poorly described and is currently under discussion. We present a study of two strains of SARS-CoV-2 detected in the same patient during the same disease presentation.Case presentationA patient in their 90 s was hospitalised with fever. Oropharyngeal swab obtained on the next day (sample 1) tested positive for SARS-CoV-2. Five days later, the patient was transferred to the ICU (intensive care unit) of the hospital specialising in the treatment of COVID-19 patients, where the patient's condition progressively worsened and continuous oxygen insufflation was required. Repeated oropharyngeal swab (sample 2), which was taken eight days after the first one, also tested positive for SARS-CoV-2. After 5 days of ICU treatment, the patient died. The cause of death was a coronavirus infection, which progressed unfavourably due to premorbid status. We have performed sequencing of full SARS-CoV-2 genomes from oropharyngeal swabs obtained eight days apart. Genomic analysis revealed the presence of two genetically distant SARS-CoV-2 strains in both swabs. Detected strains belong to different phylogenetic clades (GH and GR) and differ in seven nucleotide positions. The relative abundance of strains was 70% (GH) and 30% (GR) in the first swab, and 3% (GH) and 97% (GR) in the second swab.ConclusionsOur findings suggest that the patient was infected by two genetically distinct SARS-CoV-2 strains at the same time. One of the possible explanations is that the second infection was hospital-acquired. Change of the dominant strain ratio during disease manifestation could be explained by the advantage or higher virulence of the GR clade strain.

Evaluation of the Boussignac Cardiac arrest device (B-card) during cardiopulmonary resuscitation in an animal model

Aim of the studyThe purpose of this study was to examine continuous oxygen insufflation (COI) in a swine model of cardiac arrest. The primary hypothesis was COI during standard CPR (S-CPR) should result in higher intrathoracic pressure (ITP) during chest compression and lower ITP during decompression versus S-CPR alone. These changes with COI were hypothesized to improve hemodynamics. The second hypothesis was that changes in ITP with S-CPR+COI would result in superior hemodynamics compared with active compression decompression (ACD) + impedance threshold device (ITD) CPR, as this method primarily lowers ITP during chest decompression. MethodsAfter 6min of untreated ventricular fibrillation, S-CPR was initiated in 8 female swine for 4min, then 3min of S-CPR+COI, then 3min of ACD+ITD CPR, then 3min of S-CPR+COI. ITP and hemodynamics were continuously monitored. ResultsDuring S-CPR+COI, ITP was always positive during the CPR compression and decompression phases. ITP compression values with S-CPR+COI versus S-CPR alone were 5.5±3 versus 0.2±2 (p<0.001) and decompression values were 2.8±2 versus −1.3±2 (p<0.001), respectively. With S-CPR+COI versus ACD+ITD the ITP compression values were 5.5±3 versus 1.5±2 (p<0.01) and decompression values were 2.8±2 versus −4.7±3 (p<0.001), respectively. ConclusionCOI during S-CPR created a continuous positive pressure in the airway during both the compression and decompression phase of CPR. At no point in time did COI generate a negative intrathoracic pressures during CPR in this swine model of cardiac arrest.

A ventilation technique for oxygenation and carbon dioxide elimination in CPR: Continuous insufflation of oxygen at three levels of pressure in a pig model

Pulmonary ventilation remains an important part of cardiopulmonary resuscitation, affecting gas exchange and haemodynamics. We designed and studied an improved method of ventilation for CPR, constructed specifically to support both gas exchange and haemodynamics. This method uses continuous insufflation of oxygen at three levels of pressure, resulting in tri-level pressure ventilation (TLPV). We hypothesized that TLPV improves gas exchange and haemodynamics compared to manual gold standard ventilation (GSV). In 14 pigs, ventricular fibrillation was induced and automated CPR performed for 10 min with either TLPV or GSV. After defibrillation, CPR was repeated with the other ventilation method. Gas exchange and haemodynamics were monitored. Data are presented as mean±standard error of the mean. TLPV was superior to GSV for PaO2 (163±36 mmHg difference; P=0.001), and peak AWP (-20±2 cmH2O difference; P=0.000) and higher for mean AWP (8±0.2 cmH2O difference; P=0.000). TLPV was comparable to GSV for CPP (5±3 mmHg difference; P=0.012), VCO2 (0.07±0.3 mL/min/kg difference; P=0.001), SvO2 (4±3%-point; P=0.001), mean carotid flow (-0.5±4 mL/min difference; P=0.016), and pHa (0.00±0.03 difference; P=0.002). The PaCO2 data do not provide a conclusive result (4±4 mmHg difference). We conclude that the ventilation strategy with a tri-level pressure cycle performs comparable to an expert, manual ventilator in an automated-CPR swine model.

Effect of continuous oxygen insufflation on induced-gastric air volume during cardiopulmonary resuscitation in a cadaveric model

BackgroundThe main objective of this study was to compare the volume of gas insufflated in the stomach with continuous external chest compressions plus continuous oxygen insufflation (C-CPR) versus standard-CPR (S-CPR) which alternates external chest compressions and synchronized positive insufflations through a bag-valve-mask with a 30/2 ratio. The secondary objective was to compare upper airway pressures (intratracheal and intramask) generated during continuous oxygen insufflation. Material and methodsOpen, prospective, randomized, cross over, comparative, non-inferiority study. CPR was performed for six minutes periods, on seven fresh human corpses, with C-CPR or S-CPR in a random order. Before each CPR period, the stomach was completely emptied through the gastrostomy tube, and then 200mL of air was injected in the stomach to be sure it was not collapsed. The gastric volume was measured at the end of each intervention. Intratracheal and intramask pressures were recorded continuously during C-CPR. Results were provided as mean±standard deviation. Statistical analyses were done with a paired student t test. ResultsInduced-gastric inflation was lower with C-CPR (221±130mL) than with S-CPR (5401±2208mL, p=0.001). Throughout C-CPR, no difference was found between the intratracheal and intramask pressures (4.4±1.2; 4.0±0.8cmH2O, respectively, p=0.45). ConclusionThis human cadaver study demonstrates that continuous oxygen insufflation induced less gastric inflation than intermittent insufflation during CPR.

Even short-time storage in physiological saline solution impairs endothelial vascular function of saphenous vein grafts

A faultless endothelial layer is decisive for vascular function and therewith graft's patency. Functional impairment of the endothelium increases risk of graft thrombosis, intimal hyperplasia, and consecutive accelerated graft atherosclerosis. Storage solutions for intra-operatively harvested saphenous vein segments (SVS) might have significant impact on endothelial function. We investigated the impact of short-time storage in physiological saline solution (PSS) and a potassium-chloride- and N-acetylhistidine-enriched storage solution on venous endothelial function. Intra-operatively isolated SVSs (n=19) were stored in different storage solutions for 90 min. They were then immediately studied in tissue bath at 36°C with continuous oxygen insufflation. Following preconstriction with norepinephrine, dose-response relaxation curves of bradykinine (Brad) and sodium nitroprusside (SNP) were determined. We compared developed maximum wall tension, vessel constriction kinetics, endothelial cell- and smooth muscle cell (SMC)-dependent vasodilatory function. Maximum vessel wall tension was reduced significantly in PSS-stored vessels (10.1 ± 9.8 mN mm(-1) vs 3.5 ± 3.4 mN mm(-1); p=0.0372). Endothelium-derived vasodilatory function was likewise significantly reduced after short-time storage (20.6 ± 34.4% vs 35.0 ± 27.0%; p=0.0437). SNP-mediated SMC-vasodilatory function was maintained equally well in both groups (88.2 ± 21.8% vs 83.0 ± 30.6% in PSS; p=n.s.). Even short-time storage in PSS significantly impairs endothelial vascular function. Concerning the essential role of a faultless endothelial layer, the quite common use of PSS as a storage solution for SVSs in CABG surgery has to be discussed critically.

A two-bougie technique for safer oro- to nasotracheal tube exchange in a difficult airway

There is a considerable risk of loss of airway control during an oro- to nasotracheal tube exchange in a patient with a difficult airway. Various techniques have been described to negotiate this potentially life-threatening situation safely [1–3]. We describe a simple and effective two-bougie technique, which facilitated a safe oro- to nasotracheal tube exchange, in a patient with a known difficult airway. A 56-year-old, 90-kg man with hepatic cirrhosis required emergency tracheal intubation and ventilatory support for acute respiratory distress. Orotracheal intubation was difficult, necessitating two attempts and the use of a stylet. We assessed his laryngoscopy as Cormack and Lehane grade 3 and inserted an 8.5-mm cuffed tracheal tube. Subsequently, the patient required endoscopic oesophageal variceal ligation, so we were requested to re-intubate the trachea nasally, to facilitate the procedure. With the orotracheal tube in situ, we introduced an 8.0-mm cuffed tracheal tube nasally into the oropharynx. We then inserted a gum-elastic bougie through the nasal tube and further advanced this bougie alongside the previously placed orotracheal tube. We then guided this bougie towards the glottis and into the trachea with the help of direct laryngoscopy, external laryngeal pressure, Magill forceps and the sensation of tracheal clicks as it slid into the trachea. We then inserted a second bougie through the orotracheal tube, into the trachea and removed the orotracheal tube after cuff deflation, leaving the oral bougie in the trachea. We then advanced the nasal tube into the trachea over the nasal bougie and confirmed its position by auscultation and capnography following the removal of the bougie. Finally, the oral bougie was also removed. The patient’s cardiovascular parameters and oxygen saturation were maintained throughout the tube exchange, which took only a few minutes. Several devices and techniques have been described for oro- to naso tracheal tube exchange, such as a tracheal tube exchanger, gum-elastic bougie and flexible fibreoptic bronchoscope [1–3]. However, these techniques have disadvantages such as a difficult technique, complex equipment and most importantly, potential for loss of airway control on removal of the oral tube. Our technique was fairly simple. While the nasal bougie facilitated nasal intubation, in the event of an unsuccessful nasal intubation or accidental dislodgement during the transition, the oral bougie served as a standby for immediate re-intubation. The bougies did not encroach significantly into the available oral workspace required for the various manoeuvres during the procedure. Ideally, we would have preferred to use an airway exchange catheter instead of a bougie through the oral tube as the continuous oxygen insufflation through the former would have added to the safety of the procedure, but we do not have these devices available in our hospital. In conclusion, a two-bougie technique can be a useful method for safer oro- to nasotracheal tube exchange, in patients with difficult airways. No external funding and no competing interests declared. Published with written assent from the patient’s next of kin (patient unfortunately deceased).

Continuous Anesthetic Insufflation and Topical Anesthesia of the Airway Using Trachlight in Chronic Facial Burns

To the Editor: In chronic burn patients undergoing reconstructive surgery, securing a patient airway quickly, atraumatically, and, preferably, on the first attempt is a challenge. We describe a patient of chronic severe burns in whom fiberoptic endotracheal intubation failed but in whom a modified Trachlight intubation enabled us to secure the airway uneventfully. An ASA physical status III 35-yr-old man with history of epileptic convulsions presented with severe burns of the head, neck, and chest sustained 7 mo previously (Fig. 1). The patient was scheduled for transfer of pedicle flap to the forehead.Figure 1.: Modified Trachlight intubation in progress. A: Syringe with local anesthetic, B: Trachlight in the process of placement, C: Infant feeding tube attached to continuous anesthetic insufflation line.The patient had a mouth opening of 1.0 cm and neck extension was restricted because of two bands of anterior neck contracture. There was complete destruction of both the eyes and external nose. The turbinates and nasal passages had granulation tissue. All other relevant investigations were within normal limits. The patient refused an awake tracheal intubation. Anesthesia was induced with halothane in 100% oxygen. Fiberoptic intubation was attempted after topical nasal application of ephedrine 0.75% but failed as a result of bleeding. A size 5F infant feeding tube was attached beginning from the tip of the Trachlight to the wand. The Trachlight-endotracheal tube assembly was now configured into a “C-shape” against the patient's lateral facial profile (Fig. 1). The tip of the wand was placed at the thyroid cartilage; the next bend was taken at the level of the posterior one third of the mandible such that the other end of the C portion of the wand was approximately at the level of the external nasal opening. The Trachlight with infant feeding tube in a 7.0 mm inner diameter endotracheal tube was now introduced and maneuvered so as to make the glow of light appear in the midline just below the scar. At this juncture 1 mL of 2% lidocaine was injected with moderate force via the infant feeding tube. After waiting for 60 s, the Trachlight glow was gradually moved into the larynx (Fig. 2). Minimal coughing and bucking were noted, and a second 1 mL of 2% lidocaine was injected through the infant feeding tube. The stylet was partially withdrawn and Trachlight-endotracheal tube assembly was taken until the light glow just disappeared under the suprasternal notch. The clamp was released, the Trachlight disengaged and removed, and correct endotracheal tube placemen was confirmed. During this period, the patient continued to receive 4 L of oxygen and 2% halothane via the infant feeding tube (Fig. 2) except for two brief periods when lidocaine was injected through the infant feeding tube. The entire procedure lasted 11 min. Oxygen saturation remained between 97% and 99%.Figure 2.: Trachlight endotracheal tube assembly in the trachea with a well circumscribed glow in the front of the neck. A: Continuous anesthetic insufflation through infant feeding tube, B: Well circumscribed light glow, C: Trachlight-endotracheal tube assembly.Tracheostomy was avoided, as it would result in loss of speech in an illiterate and visually handicapped patient. We therefore opted for Trachlight-aided intubation with an attached size 5F infant feeding tube on the side of the wand. This gave us the flexibility of using this additional tubing for continuous insufflation of oxygen and halothane during a procedure tending to be prolonged. This also gave us the option of injecting lidocaine on the glottic and intratracheal structures to obtund coughing and bucking on the tracheal tube. In conclusion, using an infant feeding tube with Trachlight-endotracheal tube assembly serves the triple function of assisting intubation, maintaining inhalational anesthesia, and administering topical local anesthetic. Ashutosh Bhardwaj, MBBS Saad N. Kidwai, MBBS Vijayata Verma, MBBS Nazish Nabi, MBBS Meraj Ahmad, MBBS Rashid M. Khan, MD Department of Anesthesiology J.N. Medical College A.M.U., Aligarh India [email protected]

Continuous insufflation of oxygen (CIO) during cardiopulmonary resuscitation (CPR): preliminary results of a randomised controlled trial

The use of CIO through a special 'Boussignac' endotracheal tube during CPR for out-of-hospital cardiac arrest has been shown to be as efficient as standard manual ventilation and chest compression in terms of immediate resuscitation [1]. A multicentre trial was therefore undertaken to compare the outcome associated with CIO-CPR versus standard CPR. We report the preliminary results concerning the respective efficacy of the two techniques on oxygenation.

Efficacy of Continuous Insufflation of Oxygen Combined with Active Cardiac Compression-Decompression During Out-of-Hospital Cardiorespiratory Arrest

Efficacy of Continuous Insufflation of Oxygen Combined with Active Cardiac Compression-Decompression During Out-of-Hospital Cardiorespiratory Arrest

Field Evaluation of Experimental Cardiopulmonary Resuscitation Techniques

Field Evaluation of Experimental Cardiopulmonary Resuscitation Techniques

New equipment to prevent carbon dioxide rebreathing during eye surgery under retrobulbar anaesthesia

BACKGROUNDCarbon dioxide concentration under ophthalmic drapes increases during eye surgery under local anaesthesia. A new prototype has been designed which combines continuous suction of carbon dioxide enriched air and continuous...

Interest of a Therapeutic Optimization Strategy in Severe ARDS

Evaluate the interest of the response to a therapeutic optimization as a predictor of prognosis in ARDS. Prospective study. ICU of a University Hospital. Thirty-six consecutive patients with severe ARDS addressed for extracorporeal carbon dioxide removal (ECCO2R). We studied the response during the first 2 days after arrival to the therapeutic optimization strategy consisting in a combination of the following: (1) decrease in extravascular lung water (diuretics or hemofiltration); (2) selection of the best ventilatory mode; (3) permissive hypercarbia; and (4) correction of hypoxemia by alveolar recruitment, additional continuous oxygen insufflation, body position changes (prone position), inhaled nitric oxide, enhancement of hypoxic pulmonary vasoconstriction with almitrine, and drainage of pleural or mediastinal effusions. In patients remaining severely hypoxemic despite these modalities, ECCO2R was then proposed. Thirty-six patients were addressed after 8.3+/-5.5 days of mechanical ventilation. On arrival, mean simplified acute physiologic score was 46.8+/-14.2, multiple system organ failure score was 1.8+/-1.6, Murray score was 3.4+/-0.4, PaO2 was 75.3+/-31.3 (fraction of inspired oxygen [FIO2]=1) for a positive end-expiratory pressure level of 12.3+/-3.4 cm H2O. Nineteen of 36 patients improved their gas exchange within 2 days and their mortality was 21%. The seventeen remaining patients did not improve PaO2/FIO2; PaCO2 and airway pressures remained high and their mortality was 88%. This different response to therapeutic optimization appeared using stepwise logistic regression as the most predictive factor for mortality (p<0.05). In patients with severe ARDS, the response to an early performed therapeutic optimization used to improve hypoxemia appeared to be a highly discriminant factor distinguishing deceased from surviving patients.

New Set of Pediatric Laryngoscopes

With new advances in pediatric otolaryngology, the awareness of difficulties with existing laryngoscope instruments has become more apparent. The following paper introduces four new pediatric laryngoscopes for use in premature infants, the neonate and infant, the toddler-size child, and the preadolescent-size child. The reasons for the need of new laryngoscopes are explained, and the modifications to existing scopes that are currently employed are discussed. The need for continuous insufflation of oxygen during difficult as well as routine intubation is underscored with reference to the current anesthesia literature. Ventilating techniques in laryngoscopy for the non-respirator-dependent child are discussed.

Effects of tracheal suctioning on neonates: a review of the literature

In summary, endotracheal suctioning is not a benign procedure. Immediate negative effects associated with tracheal suctioning include: hypoxemia, changes in heart rate, blood pressure, intracranial pressure and pneumothoraces. Other potential long term effects include mucosal trauma and sepsi. Factors which may contribute to the immediate negative effects throughout the suctioning procedure include: length of time away from the oxygen source, both the duration and magnitude of applied suction, the ratio of diameters of suction catheter to endotracheal tube, intillation of normal saline, depth of catheter insertion and the amount the infant is handled throughout the procedure. Strategies to minimise these negative effects during suctioning include: preoxygenation with hyperventilation or continuous insufflation of oxygen, limiting the depth of catheter insertion to just beyond the distal end of the endotracheal tube, use of sedation and minimising infant handling.

Continuous low-flow supracarinal and subcarinal oxygen insufflation in addition to intermittent positive-pressure ventilation does not improve gas exchange

Recent studies in animals have demonstrated that continuous insufflation of oxygen near the tracheal carina results in ventilation and carbon dioxide removal that is proportional to the flow rate. The purpose of this study was to determine whether the addition of supracarinal and subcarinal low-flow oxygen insufflation to conventional intermittent positive-pressure ventilation (IPPV) of critically ill and anesthetized patients results in increased ventilation and improved oxygenation. In eight studies a supracarinal catheter (3.7 mm ON was placed 1 to 2 cm above the carina, and in another eight studies two subcarinal catheters (1.7 mm ON were placed 2 cm below the tracheal carina under direct vision with a fiberoptic bronchoscope. Both supracarinal and subcarinal catheters were passed within the lumen of an 8 mm ID endotracheal tube. In both groups, conventional IPPV consisted of a tidal volume of 10–12 mL/kg, respiratory rate of 8 to 10 breaths/min, O cm H 2O positive end-expiratory pressure (PEEP), and F 1O 2 of 1.0. In both groups, continuous oxygen insufflation flow rates were 0.05, 0.10, and 0.20 L/ kg/min. It was found that compared with control conditions (no insufflation), oxygen insufflation at all flow rates in both supracarinal and subcarinal insufflation groups did not cause any significant change in either oxygenation or ventilation. There was a significant increase in proximal peak airway pressure with each incremental increase in continuous oxygen flow rate. Conversely, there was a significant decrease in mean arterial pressure and cardiac output with each incremental increase in continuous oxygen flow rate. It is concluded that use of continuous low-flow insufflation of oxygen with simple administration systems (catheters within the lumen of endotracheal tube) in addition to conventional IPPV is contraindicated at the present time. Further studies using different insufflation systems may prove to be worthwhile.

One-Lung Ventilation. The Effect of Positive End Expiratory Pressure to the Nondependent and Dependent Lung

Summary We applied positive end expiratory pressure to the nondependent, nonventilated lung, or both non-dependent and dependent, ventilated lung during one lung anaesthesia, and compared the results to those obtained by other techniques, such as increasing the inspired oxygen concentration in the dependent lung, or insuffating with oxygen using positive end expiratory pressure in the nondependent lung. Our study suggests that arterial oxygenation and intrapulmonary shunt can be lessened during one lung ventilation by continuous oxygen insufflation of the nondependent lung at 0.98 kPa positive end expiratory pressure while the dependent lung is ventilated with 0.49 kPa positive end expiratory pressure.

One-lung ventilation. The effect of positive end expiratory pressure to the nondependent and dependent lung.

We applied positive end expiratory pressure to the nondependent, nonventilated lung, or both nondependent and dependent, ventilated lung during one lung anaesthesia, and compared the results to those obtained by other techniques, such as increasing the inspired oxygen concentration in the dependent lung, or insufflating with oxygen using positive end expiratory pressure in the nondependent lung. Our study suggests that arterial oxygenation and intrapulmonary shunt can be lessened during one lung ventilation by continuous oxygen insufflation of the nondependent lung at 0.98 kPa positive end expiratory pressure while the dependent lung is ventilated with 0.49 kPa positive end expiratory pressure.

Experiments on the prolongation of induced epileptiform convulsions in the cat.

THE present paper offers a brief summary of work which has been published in German journals dealing with the prolongation of induced convulsions. In the course of my experimental research the following phenomena were demonstrated:(1)Continuousconvulsionslastingup to oneand a half hours were produced by the administration of oxygen and adrenaline, preceded by the injection of phenyl-methyl-aminopropane.(2)Prolonged convulsions of 33 minutes were produced by the intravenous injection of 2 ml. of a io per cent. metrazol solution and continuous oxygen in suffiation.(3)Isolated continuous convulsive activity of the cerebellum was produced lasting 30 minutes after cessation of respiration and of all cortical electrical activity. This was achieved by continuous insuffiation of oxygen together with the injection of adrenaline and strychnine.(4)Activation of a prolonged convulsion up to 11 minutes, without further electric stimulation, was effected via the thalamus by the injection of adrenaline after administration of phenyl-methyl-aminopropane and continuous oxygen in sufflation.