|Year : 2017 | Volume
| Issue : 1 | Page : 1-2
Non-invasive ventilation – An effective way of delivering air for two?
Anjan Trikha1, AA Kumar2
1 Department of Anaesthesiology Pain Medicine and Critical Care, All India Institute of Medical Sciences, New Delhi, India
2 Department of Anaesthesiology, Institute of Liver and Biliary Disease, Vasant Kunj, New Delhi, India
|Date of Web Publication||1-Jun-2017|
Department of Anaesthesiology Pain Medicine and Critical Care, All India Institute of Medical Sciences, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Trikha A, Kumar A A. Non-invasive ventilation – An effective way of delivering air for two?. J Obstet Anaesth Crit Care 2017;7:1-2
|How to cite this URL:|
Trikha A, Kumar A A. Non-invasive ventilation – An effective way of delivering air for two?. J Obstet Anaesth Crit Care [serial online] 2017 [cited 2017 Oct 23];7:1-2. Available from: http://www.joacc.com/text.asp?2017/7/1/1/207388
Non-invasive ventilation (NIV) is in vogue and its indications and reports of successful outcomes after its use in different sub group of patients are increasing in a geometric progression. It has become a useful modality in treating patients with both acute and chronic respiratory failure, although its role in the latter still needs to be defined. One of the most important aspects of NIV is its usage as an alternative to invasive ventilation and thus avoiding all the risks, complications and side effects of endotracheal intubation and artificial ventilation. One of the commonly mentioned complications associated with NIV is gastric distension due to the inhaled oxygen and air going to the stomach due to the high pressure and flow rates of the gases used. However, in routine, gastric distension is rarely a problem with NIV especially as long as the peak inspiratory pressures do not exceed 25 cm of H2O. Insertion of nasogastric tubes that are usually placed in patients needing respiratory support can prevent the distension but invariably cause a leak from the mask thereby decreasing the effective pressure. In addition, the nasogastric tubes bypass the lower oesophageal sphincter, which would increase the possibility of reflux. Use of NIV in parturients remains controversial because pregnant women have higher risk of aspiration of gastric contents because of decreased gastric-emptying time owing to increased plasma progesterone with reduced lower esophageal sphincter tone, increased abdominal pressure from the gravid uterus with displacement of stomach and decreased motility.,
Although acute respiratory failure from whatever cause occurs in only about 0.1% of all pregnancies, it is one of the most common indications for admission of a parturient in an intensive care unit (ICU) and is associated with high morbidity and mortality for the mother and the unborn baby. During pregnancy, acute respiratory failure is usually due to infections, eclampsia, pulmonary oedema from varied causes, Acute Respiratory Distress Syndrome (ARDS), as well as pre-pregnancy chronic thoracic conditions such as neuromuscular disorders and kyphoscoliosis. The inherent issues of foetal safety of medications like anxiolytics, sedatives and analgesics that are necessary for endotracheal intubation and ventilation make the modality of NIV very attractive, as most of these medications are not essential for it.
Currently, there are no guidelines regarding use of NIV in parturients and little is known about the safety and efficacy of NIV for the management of respiratory failure in pregnancy. However, its use in this population shows promise as demonstrated by favorable outcomes in existing reports in the literature. Given the paucity of published data, there are few case series and reports, as mentioned later, where this modality has been used in parturients, most of the time successfully. It is evident from these reports that NIV can be used in parturients with different diseases leading to respiratory failure.
Some of the earliest reports described the use of NIV in parturients with chronic respiratory failure due to poliomyelitis, scoliosis or neuromuscular disorders.,,, Thereafter, reports of successful usage of NIV in parturients with hypoxemic respiratory failure due to different causes (pulmonary oedema due to tocolytics, severe pre eclampsia, pneumonias due to aspiration/viral infection, sepsis, aspiration pneumonia) were published.,,, No major side effects attributable to the use of NIV were reported in all these patients. Despite these reports with excellent outcomes, controversy regarding the regular use of NV in this sub group of patients remains. The likely reasons for this are discussed below.
It is common knowledge that in an adult ICU pregnant patients are generally not “welcome” due to various reasons – ranging from non-availability of trained healthcare personnel in obstetric care in an adult ICU, absence of monitoring facilities of the foetus and apprehension regarding the use of medications in a pregnancy. The apprehensions of the regular ICU staff are not unfounded. Regular ICU training does not include obstetric physiology, monitoring of well being of the fetus and fundamentals of obstetric intensive care. The majority of obstetric patients admitted in an adult ICU are usually following complications arising after vaginal or cesarean delivery or after foetal loss. A change in the teaching curriculum and the staff mindset is needed in this regard. Presence of foetal monitors and familiarity in their usage and their interpretation by the staff of an ICU is essential.
NIV has become a standard norm in most of the hospitals and is even been used out of the ICU setting. With so much experience it is time that its regular use in parturients should be advocated. Needless to mention, patient selection in this sub group of patients, and expert staff (who can identify early signs of NIV failure) to institute and monitor such patients are of prime importance. All other issues – possibility of aspiration due to gastric distension, reflux and decreased gastric motility can be easily addressed with use of time-tested medications that are regularly used for anaesthesia in pregnancy.
An important thing to remember regarding NIV use in parturients is the difficult airway associated with it and the fact that airway difficulty can change during the course of pregnancy. It seems logical that threshold for calling off NIV trial in such pregnant patients should be low and should also be dependent upon foetal heart monitoring. Endotracheal intubations should preferably be done when expert staff is available as intubating a term pregnant hypoxic patient on an ICU bed can be a nightmare.
In conclusion, NIV can be considered a safe option for respiratory assistance in selected group of parturients with acute respiratory failure. However, for successful outcomes in addition to everything else in an ICU, staff with familiarity of NIV, foetal well-being monitors, low thresh hold for endotracheal intubation and knowledge of obstetric critical care is essential. It is unlikely that randomized closed trials with sufficient number of patients would be carried to provide strong evidence for use of NIV in parturients.
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Conflicts of interest
There are no conflicts of interest.
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