Outline the role of monitoring  in the management of upper airway obstruction.

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College Answer

Monitoring should  be  considered as  either  part  of  routine  examination (clinical  monitoring) or requiring  additional equipment or  investigations. Assumed in  this  case  that  the  presence of  an endotracheal tube or tracheostomy would prevent upper airway obstruction.

Clinical: essential part  of monitoring. Clinical  criteria more likely  to lead to decision to intervene. Consider  importance of  assessment of  level  of  consciousness, extent  of  obstruction (soft  tissue iodrawing- suopraclivular, tracheal  tug,  intercostal muscles), and  ability  to cope  with  increased work of breathing (tachycardia, tachypnoea, sweating).

Equipment:  pulse   oximetry  (limited   information,  better   with   lower   FlO2), 

 ECG  (rhythm, ischaemia),  capnograph   (respiratory  rate,  pattern    of   expiratory   flow),    invasive   pressures (IA/CVP/PAWP - may  help  assess  extent  of  intrathoracic pressure  change and therefore work  of breathing).

Investigations: arterial  blood  gases (direction of  change may  assist  in  decision to intervene eg. CO2/pH).

Discussion

it is difficult to come up with a systematic answer to this weird question.

Upper airway obstruction ca potentially result in the loss of the whole airway, and this would manifest in a number of ways.

Physical examination findings (such as worsening stridor or tachypnoea) suggest that this patient should undergo serial examinations.

The earliest machine-monitored sign that the patient cannot breathe (or that the airway is closing) would be continuous capnometry.

Pulse oximetry would alert you to when it is already too late, and the patient is desperately hypoxic.

ABG analysis will tell you when the patient is tiring of breathing though their obstructed airway, and this may lead you to finally intubate them.