**5. Sedation outside OR**

With respect to administrating sedation outside the OR environment two aspects need to be emphasized:

**Oxygen therapy modalities:** These could be either low-flow administration or high-flow administration [3]. Low-flow methods are usually employed for the majority of sedation that happens outside the OR. These may be via nasal cannulae with flow rates between 2 and 6 L/min or face masks, including simple masks, venturi masks, or non-rebreathing masks, with flow rates up to 15 L/min. High-flow nasal cannula (HFNC) is a nasal cannula with the capability of delivery humidified oxygen at flow rates that exceed the inspiratory pressure of the patient (60–70 L/ min). It allows delivery of 100% oxygen, and can be given to achieve transient apneic oxygenation.

**Medication for sedation:** Choosing sedative agents that cause minimal depression of the ventilatory drive is safer when dealing with patients away from the OR. Fentanyl and Midazolam are the most commonly used sedative agents, with an added advantage of having antagonists available. Ketamine and Ketamine-Propofol mixtures are also used. Dexmedetomidine is known to preserve upper airway reflexes and the ventilatory drive. Propofol should be used only with the option

**45**

anesthesia (**Table 2**).

**6. Monitoring**

**Table 2.**

*Airway Management Outside the Operating Room DOI: http://dx.doi.org/10.5772/intechopen.93362*

**Adults**

titrated boluses (×3)

0.5 mg/kg q5 min

over 10 min

**Onset Duration Comments**

1–5 min 30–90 min Usually used along with

<1 min 3–10 min Causes drop in BP, reduced

5–30 min 1–2 h Minimal respiratory

Fentanyl

inotropy (caution in hypovolemic patients and HF patients) Can cause hypoventilation or apnea

drive Has bronchodilatory effects Can cause hypersalivation (may need anticholinergic) Can cause increase in HR, BP, ICP and emergence delirium

depression Can decrease SVR and HR

**Drug IV dose in** 

Midazolam 1–2 mg

Propofol 1 mg/kg then

Dexmedetomidine 0.5–1 mcg/kg

*pressure, SVR-systemic vascular resistance).*

of airway rescue available, as the patient may move from deep sedation to general

*Commonly used drugs for sedation (BP-blood pressure, HF-heart failure, HR-heart rate, ICP-intracranial* 

Fentanyl 0.5–2 mcg/kg 2–3 min 20–30 min Can cause hypoventilation

Ketamine 0.25–1 mg/kg 30 sec 5–10 min Does not depress ventilatory

Maintaining standards of monitoring is the most important modality used to ensure the safety of the patient and to avoid airway complications. Adherence to the current best practice guidelines [4] is essential when planning and equipping areas outside the OR. This should include the pulse oximeter and capnograph. Failure of capnography contributed to 74% of cases of death or persistent neurological injury [5]. **Figure 5** shows a snapshot of a monitor used in a patient who is deeply sedated with a Target Controlled Infusion (TCI) of Propofol, spontaneously breathing with supplemental oxygen delivered via a nasal cannula. No other airway adjuncts were necessary. The nasal cannula is incorporated with a sampling port for expired gases (**Figure 6**) and a clear EtCO2 (end tidal carbon dioxide) trace and value is displayed on the monitor. In a fully open circuit as is with nasal prongs, the value displayed is dependent on the flow of oxygen delivered and the depth of breathing. Although the exact value displayed is not of true significance always, the characteristics of the trace and the trend of the number displayed warns clinicians of impending airway compromise and the need to intervene. Capnography use has the highest potential to prevent deaths from airway

Monitoring depth of sedation has been looked at using a bispectral index (BIS) monitor. The depth of sedation is calculated by measuring cerebral electric activity via an electroencephalogram (EEG). The BIS algorithm processes the frontal EEG and converts the signal to a waveform on the BIS monitor, and displays a number between

complications outside of the operating theater complex [6, 7].

**Drug IV dose in Adults Onset Duration Comments** Midazolam 1–2 mg titrated boluses (×3) 1–5 min 30–90 min Usually used along with Fentanyl Fentanyl 0.5–2 mcg/kg 2–3 min 20–30 min Can cause hypoventilation Propofol 1 mg/kg then 0.5 mg/kg q5 min <1 min 3–10 min Causes drop in BP, reduced inotropy (caution in hypovolemic patients and HF patients) Can cause hypoventilation or apnea Ketamine 0.25–1 mg/kg 30 sec 5–10 min Does not depress ventilatory drive Has bronchodilatory effects Can cause hypersalivation (may need anticholinergic) Can cause increase in HR, BP, ICP and emergence delirium Dexmedetomidine 0.5–1 mcg/kg over 10 min 5–30 min 1–2 h Minimal respiratory depression Can decrease SVR and HR

#### *Airway Management Outside the Operating Room DOI: http://dx.doi.org/10.5772/intechopen.93362*

#### **Table 2.**

*Special Considerations in Human Airway Management*

fluoroscopy rooms, the C-arms of the fluoroscope will move in multiple axes and can come in the way of airway or monitoring equipment intra-procedure. Very little consideration is given to airway equipment placement in these areas as not all procedures require patient sedation or airway manipulation. It is therefore important to reshuffle equipment, in discussion with the operator, to make sure airway

**Radiation exposure:** Patients and staff are exposed to high doses of ionizing radiation in the radiology suite. Radiation exposure poses a significant health risk. Measures taken to minimize exposure and risk during the procedure include wearing protective lead aprons, thyroid shields, eye protection, radiation exposure badges (to log exposure) and distancing oneself as far as possible from the radia-

With respect to administrating sedation outside the OR environment two

**Oxygen therapy modalities:** These could be either low-flow administration or high-flow administration [3]. Low-flow methods are usually employed for the majority of sedation that happens outside the OR. These may be via nasal cannulae with flow rates between 2 and 6 L/min or face masks, including simple masks, venturi masks, or non-rebreathing masks, with flow rates up to 15 L/min. High-flow nasal cannula (HFNC) is a nasal cannula with the capability of delivery humidified oxygen at flow rates that exceed the inspiratory pressure of the patient (60–70 L/ min). It allows delivery of 100% oxygen, and can be given to achieve transient

**Medication for sedation:** Choosing sedative agents that cause minimal depression of the ventilatory drive is safer when dealing with patients away from the OR. Fentanyl and Midazolam are the most commonly used sedative agents, with an added advantage of having antagonists available. Ketamine and Ketamine-Propofol mixtures are also used. Dexmedetomidine is known to preserve upper airway reflexes and the ventilatory drive. Propofol should be used only with the option

maintenance and management is kept safe throughout the procedure.

**44**

tion source.

**Figure 5.** *Basic monitoring.*

**5. Sedation outside OR**

apneic oxygenation.

aspects need to be emphasized:

*Commonly used drugs for sedation (BP-blood pressure, HF-heart failure, HR-heart rate, ICP-intracranial pressure, SVR-systemic vascular resistance).*

of airway rescue available, as the patient may move from deep sedation to general anesthesia (**Table 2**).
