Severe CO2 Retention Research Articles

Extracorporeal Membrane Oxygenation for Coronavirus Disease 2019-Induced Acute Respiratory Distress Syndrome: A Multicenter Descriptive Study*

Severe acute respiratory distress syndrome is complicated with coronavirus disease 2019 and extracorporeal membrane oxygenation support may be necessary in severe cases. This study is to summarize the clinical features, extracorporeal membrane oxygenation characteristics, and outcomes of patients with severe acute respiratory syndrome coronavirus 2 pneumonia received extracorporeal membrane oxygenation. Descriptive study from two hospitals. The ICUs from university hospitals. Patients with severe acute respiratory syndrome coronavirus 2 pneumonia received mechanical ventilation, including those underwent extracorporeal membrane oxygenation from Zhongnan Hospital of Wuhan University and Wuhan Pulmonary Hospital from January 8, 2020, to March 31, 2020. None. Clinical records, laboratory results, ventilator parameters, and extracorporeal membrane oxygenation-related data were abstracted from the medical records. One-hundred twenty-nine critically ill patients with severe acute respiratory syndrome coronavirus 2 pneumonia were admitted to ICU of the two referral hospitals. Fifty-nine patients received mechanical ventilation and 21 of them received extracorporeal membrane oxygenation support (fourteen from Zhongnan hospital and seven from Wuhan pulmonary hospital). Compared to mechanical ventilation patients without extracorporeal membrane oxygenation support, there was a tendency of decline in mortality but with no significant difference (no-extracorporeal membrane oxygenation group 24/38 [63.2%] vs extracorporeal membrane oxygenation group 12/21 [57.1%]; p = 0.782). For those patients with extracorporeal membrane oxygenation, 12 patients died and nine survived by April 7, 2020. Among extracorporeal membrane oxygenation patients, the PaCO2 prior to extracorporeal membrane oxygenation was lower (54.40 mm Hg [29.20-57.50 mm Hg] vs 63.20 mm Hg [55.40-72.12 mm Hg]; p = 0.006), and pH prior to extracorporeal membrane oxygenation was higher (7.38 [7.28-7.48] vs 7.23 [7.16-7.33]; p = 0.023) in survivors than nonsurvivors. Extracorporeal membrane oxygenation might be an effective salvage treatment for patients with severe acute respiratory syndrome coronavirus 2 pneumonia associated with severe acute respiratory distress syndrome. Severe CO2 retention and acidosis prior to extracorporeal membrane oxygenation indicated a poor prognosis.

The clinical application of tracheal gas insufflation

Tracheal gas insufflation is a non conventional respiratory support technology.It might avoid severe CO2 retention in lung protective ventilation strategy, reduce ventilator-associated lung injury, which was recommented recently.In this article, we made a brief introduction of the principle, classification and clinical applications of tracheal gas insufflation technique. Key words: Tracheal gas insufflation; Mechanical ventilation; Lung protective ventilation strategy,

Severe Carbon Dioxide Retention During Second Laparoscopic Surgery for Urgent Repair of an Operative Defect from the Preceding Laparoscopic Surgery

A 61-year-old male patient underwent laparoscopic cholecystectomy on diagnosis of acute cholecystitis. Thirteen hours later, bile leakage was noted and a second laparoscopic surgery was performed to rectify this. Severe hypercapnia and acute respiratory acidosis occurred during the act of CO2 pneumoperitoneum. The accumulated CO2 could not be eliminated effectively in spite of deliberate adjustment of the respiratory parameters. We suspected that abnormally high CO2 absorption, which outweighed the capability of physiologic elimination in the presence of acute peritonitis, was the cause of the severe CO2 retention in the second laparoscopic surgery. The patient remained intubated with mechanical ventilatory support after surgery. Excessive internal CO2 was washed out gradually and the patient was extubated successfully the next morning. Profound inflammatory responses in peritonitis may increase permeability and absorption of CO2. Hypercapnia can occur as the store of CO2 in the tissues is saturated and there is continuous inflow of external CO2. It usually takes several hours to achieve a steady state of CO2 elimination after desufflation of CO2 pneumoperitoneum and mechanical ventilatory support may sometimes be needed. In conclusion, caution should be taken against hypercapnia and respiratory acidosis in patients with peritonitis undergoing laparoscopic surgery because of the likelihood of these events occurring during the procedure.

Preparation, Premedication, and Surveillance

The main end points for sedation during endoscopy are patients' satisfaction, short duration of the procedure, and safety. During the last year, attention has focused on attempting to identify the "ideal" candidate for moderate sedation/analgesia and on the importance of providing the patient with appropriate information before the procedure. The increasing pressure to perform more procedures, reduce costs, and achieve shorter patient turnaround times has affected recent approaches to sedation during endoscopy, focusing attention on alternatives to pharmacological sedation such as providing relaxing music, using small-caliber endoscopes for unsedated peroral gastroscopy, and using magnetic endoscopic imaging to increase tolerance and reduce discomfort during colonoscopy. The results, however, have not been convincing. The role of benzodiazepines was discussed in some studies, highlighting the well-known effect of midazolam on postprocedural amnesia, its pharmacological profile and tolerability after intranasal spraying in healthy volunteers, and the efficacy and safety of this route of administration as an alternative to intravenous administration in diagnostic upper gastrointestinal endoscopy. The form of sedation for gastrointestinal endoscopy that has attracted great interest over the last year is the use of intravenous propofol, either alone or with concomitant benzodiazepines or opioids. As expected in view of the drug's known pharmacological properties, the quality of sedation was better and recovery time was shorter in patients treated with propofol. However, important questions involving the narrow therapeutic range and the mode of administration of propofol (by endoscopists or nurses, or by anesthesiologists) remain open. One important aspect of sedation procedures is prevention of cardiopulmonary complications. The use of electronic monitoring techniques, with a pulse oximeter, has been recommended as a standard procedure during digestive endoscopy; however, pulse oximetry no longer reflects the normal ventilatory functions and does not detect episodes of severe CO2 retention. CO2 monitoring by transcutaneous measurement - or better, by capnography - appears to be useful, as an alternative to pulse oximetry, as a measure of hypoventilation, and for detecting potentially important abnormalities in respiratory activity in patients undergoing sedation for gastrointestinal endoscopy. With regard to preparation for endoscopic procedures, several "ideal" formulas for bowel preparation have been presented. These include the use of sodium phosphate compounds as an alternative to polyethylene glycol electrolyte lavage solutions (PEG-ELS); however, the results so far have been conflicting. The best and most cost-effective bowel cleansing procedure for colonoscopy and sigmoidoscopy has yet to be established.

Preparation, premedication and surveillance.

The main end points for sedation during endoscopy are patients' satisfaction, short duration of the procedure, and safety. During the last year, attention has focused on attempting to identify the "ideal" candidate for moderate sedation/analgesia and on the importance of providing the patient with appropriate information before the procedure. The increasing pressure to perform more procedures, reduce costs, and achieve shorter patient turnaround times has affected recent approaches to sedation during endoscopy, focusing attention on alternatives to pharmacological sedation such as providing relaxing music, using small-caliber endoscopes for unsedated peroral gastroscopy, and using magnetic endoscopic imaging to increase tolerance and reduce discomfort during colonoscopy. The results, however, have not been convincing. The role of benzodiazepines was discussed in some studies, highlighting the well-known effect of midazolam on postprocedural amnesia, its pharmacological profile and tolerability after intranasal spraying in healthy volunteers, and the efficacy and safety of this route of administration as an alternative to intravenous administration in diagnostic upper gastrointestinal endoscopy. The form of sedation for gastrointestinal endoscopy that has attracted great interest over the last year is the use of intravenous propofol, either alone or with concomitant benzodiazepines or opioids. As expected in view of the drug's known pharmacological properties, the quality of sedation was better and recovery time was shorter in patients treated with propofol. However, important questions involving the narrow therapeutic range and the mode of administration of propofol (by endoscopists or nurses, or by anesthesiologists) remain open. One important aspect of sedation procedures is prevention of cardiopulmonary complications. The use of electronic monitoring techniques, with a pulse oximeter, has been recommended as a standard procedure during digestive endoscopy; however, pulse oximetry no longer reflects the normal ventilatory functions and does not detect episodes of severe CO2 retention. CO2 monitoring by transcutaneous measurement - or better, by capnography - appears to be useful, as an alternative to pulse oximetry, as a measure of hypoventilation, and for detecting potentially important abnormalities in respiratory activity in patients undergoing sedation for gastrointestinal endoscopy. With regard to preparation for endoscopic procedures, several "ideal" formulas for bowel preparation have been presented. These include the use of sodium phosphate compounds as an alternative to polyethylene glycol electrolyte lavage solutions (PEG-ELS); however, the results so far have been conflicting. The best and most cost-effective bowel cleansing procedure for colonoscopy and sigmoidoscopy has yet to be established.

Preparation, premedication, and surveillance.

The endoscopic literature published during the past year has once again confirmed that there is significant variation from country to country regarding whether or not patients wish to receive conscious sedation during endoscopy (and particularly colonoscopy) - and there may even be variation from one endoscopic unit to another within the same country. Particular attention has been given to attempts to identify "ideal" candidates for conscious sedation, and to the importance of providing patients with information before the procedure. It has been shown that patients who receive detailed information about a medical procedure beforehand are able to benefit from this. The role of benzodiazepines, particularly midazolam, was investigated in studies emphasizing that the dosage should be kept to the minimum that is compatible with patient comfort and successful performance of the procedure. There have been few publications comparing propofol with midazolam. As expected, in view of the known pharmacological properties of the two drugs, the quality of sedation was better and the recovery time was shorter in patients who were treated with propofol. However, important questions are still open regarding the narrow therapeutic range of propofol and the methods by which it is administered (by endoscopists or by anesthesiologists). An important aspect of sedation procedures is the prevention of hypoxia and cardiopulmonary complications. Recent endoscopic reports have added little further information concerning the well-known risk of oxygen desaturation during conscious sedation. Performing endoscopy in unsedated patients reduces, but does not eliminate, the risk of hypoxia. Among the various risk factors, it has been found that chronic respiratory failure and coronary heart disease are factors predictive of severe desaturation and relevant electrocardiographic changes. The use of electronic monitoring techniques with pulse oximetry is recommended as a standard procedure during digestive endoscopy; however, it has been observed that when supplemental oxygen is administered, pulse oximetry no longer reflects normal ventilatory function and does not detect episodes of severe CO2 retention. Transcutaneous measurement of PCO2 therefore seems more reliable as a means of assessing hypoventilation. Several papers have proposed "ideal formulas" for bowel preparation for endoscopic procedures. Various regimens have been proposed as alternatives to polyethylene glycol electrolyte lavage solution (PEG-ELS) and sodium phosphate compounds, with different results. On the whole, there is still little information regarding the best and most cost-effective method of bowel cleansing for colonoscopy and flexible sigmoidoscopy.

Noninvasive Ventilation in Chronic Obstructive Pulmonary Disease

Over the past 15 years, numerous studies have explored the possibility that intermittent ventilatory assistance using noninvasive ventilation is beneficial in patients with severe stable COPD. The results are conflicting and no sustained beneficial action has been proven, although some improvement in respiratory muscle function may occur after short-term rest, and lengthening of the total duration of sleep has been shown in a few studies. Based on the observation that studies with favorable findings have generally had considerably higher PaCO2s than studies with negative findings, the current consensus view is that patients with severe CO2 retention (PaCO2 > 50-55 mm Hg) warrant a trial of NPPV. In addition, the Health Care Financing Agency that determines Medicare reimbursement policy in the United States has recently published guidelines for use of NPPV in patients with severe stable COPD that are based partly on the consensus view. There remains a deficiency of evidence supporting this application, however, and no study has confirmed any survival benefit or sustained improvement in functional status. Of note, several uncontrolled studies suggest that days of hospital use may be reduced after initiation of NPPV in these patients, but confirmatory studies are pending. If NPPV is to be initiated in patients with severe stable COPD, a more difficult adaptation process should be anticipated than for patients with neuromuscular disease. Great care must be taken in selecting a proper mask and optimal ventilator settings, and patients usually require considerable reassurance and encouragement. Potential problems should be anticipated and prevented, if possible. With a patient and supportive approach and a willingness to devote time to the process, clinicians can help optimize the likelihood of success, but failure rates are apt to remain higher than for other forms of chronic respiratory failure until the patient subpopulations with COPD most likely to benefit from NPPV are better defined and improvements in mask and ventilator technology enhance tolerance rates.

NECROTIZING TRACHEO-BRONCHITIS: A NEW COMPLICATION OF NEONATAL MECHANICAL VENTILATION

In 1982-83 7 neonates in 2 hospitals have developed sloughing of tracheal mucosa while on assisted ventilation. Gestation ranged from 26-40 wks; weight from 0.9-3 kg. Primary diagnosis was RDS in 4, persistent fetal circulation in 2 and aspiration in 1. 5 died at 1-4 days of age. At autopsy a thick basophilic membrane of necrotic epithelium and submucosa involved the distal part of the trachea and bronchi totally obstructing the airway in 2 patients. Repeated bronchoscopy in the survivors removed the obstructive plugs. Clinically all cases showed upper airway obstruction with poor chest movement, air trapping and severe CO2 retention. Pressure limited conventional ventilators were used initially followed by a trial of high frequency oscillation in 3. Peak pressures >35 cmH20 were used in 6. Hand bagging using dry 100% O2 was given for periods of 10-90 min. to all.

Nikethamide for severe CO2 retention in exacerbations of chronic bronchitis.

Nikethamide for severe CO2 retention in exacerbations of chronic bronchitis.