Societies advise against ventilating multiple patients with a single ventilator, many children with COVID-19 are asymptomatic
By Denise Baez
NEW YORK -- March 27, 2020 -- In today’s DG Alert, we cover placing multiple patients on a single ventilator and the clinical and epidemiological features of 36 children with coronavirus disease 2019 (COVID-19) in Zhejiang, China.
Sharing mechanical ventilators should not be attempted because it cannot be done safely with current equipment, according to a consensus statement issued by the Society of Critical Care Medicine (SCCM), the American Association for Respiratory Care (AARC), the American Society of Anesthesiologists (ASA), the Anesthesia Patient Safety Foundation (APSF), the American Association of Critical‐Care Nurses (AACN), and the American College of Chest Physicians (CHEST).
The full consensus statement reads:
The physiology of patients with acute respiratory distress syndrome (ARDS) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is complex. Even in ideal circumstances, ventilating a single patient with ARDS and non-homogenous lung disease is difficult and is associated with a 40% to 60% mortality rate. Attempting to ventilate multiple patients with coronavirus disease 2019 (COVID‐19), given the issues described here, could lead to poor outcomes and high mortality rates for all patients cohorted.
In accordance with the exceedingly difficult, but not uncommon, triage decisions often made in medical crises, the statement says that it is better to purpose the ventilator to the patient most likely to benefit than fail to prevent, or even cause, the demise of multiple patients.
Attempting to ventilate multiple patients would likely require arranging the patients in a spoke-like fashion around the ventilator as a central hub. This positioning moves the patients away from the supplies of oxygen, air, and vacuum at the head of the bed. It also places the patients in proximity to each other, allowing for transfer of organisms. Spacing the patients farther apart would likely result in hypercarbia.
Spontaneous breathing by a single patient sensed by the ventilator would set the respiratory frequency for all the other patients. The added circuit volume could preclude triggering. Patients may also share gas between circuits in the absence of one‐way valves. Pendelluft between patients is possible, resulting in both cross‐infection and over‐distension. Setting alarms can monitor only the total response of the patients’ respiratory systems as a whole. This would hide changes occurring in only 1 patient.
According to the consensus statement, the reasons for avoiding ventilating multiple patients with a single ventilator are numerous. These reasons include:
- Volumes would go to the most compliant lung segments.
- Positive end‐expiratory pressure, which is of critical importance in these patients, would be impossible to manage.
- Monitoring patients and measuring pulmonary mechanics would be challenging, if not impossible.
- Alarm monitoring and management would not be feasible.
- Individualized management for clinical improvement or deterioration would be impossible.
- In the case of a cardiac arrest, ventilation to all patients would need to be stopped to allow the change to bag ventilation without aerosolizing the virus and exposing healthcare workers. This circumstance also would alter breath delivery dynamics to the other patients.
- The added circuit volume defeats the operational self‐test. The clinician would be required to operate the ventilator without a successful test, adding to errors in the measurement.
- Additional external monitoring would be required. The ventilator monitors the average pressures and volumes.
- Even if all patients connected to a single ventilator have the same clinical features at initiation, they could deteriorate and recover at different rates, and distribution of gas to each patient would be unequal and unmonitored. The sickest patient would get the smallest tidal volume and the improving patient would get the largest tidal volume.
- The greatest risks occur with sudden deterioration of a single patient (ie, pneumothorax, kinked endotracheal tube), with the balance of ventilation distributed to the other patients.
- Finally, there are ethical issues. If the ventilator can be lifesaving for a single individual, using it on more than 1 patient at a time risks life‐threatening treatment failure for all of them.
A study published in The Lancet Infectious Diseases showed that nearly half of paediatric patients with COVID-19 have neither obvious symptoms nor abnormal radiological findings.
Haiyan Qiu, MD, Ningbo Women and Children’s Hospital, Ningbo, Zhejiang, China, and colleagues analysed data from 36 children aged 1 to 16 years with laboratory-confirmed COVID-19 treated at 3 hospitals in Zhejiang between January 17, 2020, and March 1, 2020. Of the children, 32 (89%) contracted the virus through close contact with family members, 12 (33%) had a history of exposure to the epidemic area, and 8 (22%) had both exposures.
Common symptoms on admission were fever (36%) and dry cough (19%). Of those with fever, 4 (11%) had a body temperature of ≥38.5 degrees Celsius and 9 (25%) had a body temperature of 37.5 to 38.5 degrees Celsius. Elevated creatine kinase MB and decreased lymphocytes were evident in 11 (31%) patients, leucopaoenia in 7 (19%) patients, and elevated procalcitonin in 6 (17%) patients.
A little more than half (53%) of the patients had moderate clinical type COVID-19, characteristic of mild pneumonia, which improved 4 to 10 days after treatment initiation. The remaining 47% had mild clinical type disease and were either asymptomatic (28%) or had acute upper respiratory symptoms (19%). No severe or critically cases were seen.
Besides radiographic presentations, variables that were significantly associated with severity of COVID-19 were decreased lymphocytes (P = .0083), elevated body temperature (P = .0020), and high levels of procalcitonin (P = .0039), D-dimer (P = .028), and creatine kinase MB (P = .0084). Children with moderate clinical type also had positive SARS-CoV-2 real-time polymerase chain reaction (RT-PCR) test results for longer (P = .0050) and spent more days in hospital (P = .017) than did those with mild clinical type.
All children received interferon alfa by aerosolisation twice a day, 14 (39%) received lopinavir/ritonavir syrup twice a day, and 6 (17%) needed oxygen inhalation. Mean time in hospital was 14 days (SD 3) days. SARS-CoV-2 PCR results became negative after a mean of 10 days of treatment, regardless of the various initial manifestations of patients.
By Feb 28, 2020, all patients were cured and were quarantined for a further 2 weeks. Follow-up is continuing.
“By contrast with findings in adults, children with COVID-19 had milder clinical manifestations -- nearly half of paediatric patients were asymptomatic,” the authors wrote. “This asymptomatic condition is relevant if community-acquired transmission becomes the primary mode. Identification of paediatric patients without presenting symptoms will become a great challenge.”
SOURCE: American Society of Anesthesiologists, The Lancet Infectious Diseases
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