Study Design

Reduced Quality Factors

0 = no serious, - = serious,

- - = very serious

Positive Quality Factors

0 = none, + = one, ++ = multiple

Dichotomous Outcome Summary

Non-Dichotomous Outcome Summary

Brief description

Overall Quality

High, moderate, low,
very low, none

No of studies

Study Type

RoB

Indirectness

Imprecision

Inconsistency

Large Effect

Dose-Response

Confounder

# Intervention with Outcome

# Control with Outcome

RR (95% CI)

Outcome: Survival to discharge

0

N/A

Outcome: ROSC

1

EXP

0

-

-

0

0

0

0

Newborn hypoxic CPA piglet study - no difference in ROSC found between manual versus mechanical ventilation

Very low

Outcome: Surrogate markers of perfusion

2

EXP

0

-

-

0

0

0

0

Two newborn piglet asystolic CPA studies found no difference in hemodynamics during CPR with mechanical vs manual ventilation

Very low

Outcome: PaCO2

2

EXP

0

-

-

0

0

0

0

Two newborn piglet studies found no difference in PaCO2 during CPR with mechanical versus manual ventilation

Very low

Outcome: Oxygenation

2

EXP

0

-

-

-

0

0

0

Two newborn piglet studies found no difference in oxygenation during CPR with mechanical versus manual ventilation.

Very low

Introduction

Providing rescue breaths during CPR is considered important to maintain oxygenation and to optimize PaCO2. The use of a mechanical ventilator during CPR could be beneficial if it can provide appropriate respiratory support and alleviate the need for personnel to be dedicated to provision of rescue breaths. There are concerns that the positive intrathoracic pressure generated by chest compressions could interfere with the operation of a mechanical ventilator and lead to inadequate ventilation. There are no recommendations in the current human or previous veterinary CPR guidelines on the best option for providing rescue breaths to patients who develop CPA while on mechanical ventilation.1,2

Consensus on science

For the most critical outcome of Survival to discharge, we identified no studies that address the PICO question.

Outcome 2: ROSC

For the critical outcome of ROSC we identified 1 experimental study (low quality of evidence, downgraded for serious indirectness) that addresses the PICO question.3 In a newborn piglet model of hypoxic cardiac arrest, no difference was found in ROSC among groups treated with 3 different types of respiratory support during CPR (T-piece, self-inflating bag, or mechanical ventilator).3

Outcome 3: Surrogate markers of perfusion

For the important outcome of Surrogate markers of perfusion, we found 2 experimental studies (low quality of evidence, downgraded for serious indirectness).3,4 In a newborn piglet model of hypoxic cardiac arrest, no difference was found in measured hemodynamic parameters among groups treated with 3 different types of respiratory support during CPR (T-piece, self-inflating bag, or mechanical ventilator).3 In another newborn piglet study using an asystolic CPA model, there was no difference in plasma lactate concentration among groups treated with 3 different types of respiratory support (T-piece vs rebreathing bag vs ventilator).4

Outcome 4: PaCO2

For the important outcome of PaCO2, we found 2 experimental studies (low quality of evidence, downgraded for serious indirectness).3,4 In a newborn piglet model of hypoxic cardiac arrest, no difference was found in PaCO2 among groups treated with 3 different types of respiratory support during CPR (T-piece, self-inflating bag, or mechanical ventilator).3 In another newborn piglet study using an asystolic CPA model, there was no difference in PaCO2 among groups treated with 3 different types of respiratory support (T-piece vs rebreathing bag vs ventilator).4

Outcome 5: Oxygenation

For the important outcome of Oxygenation, we found 2 experimental studies (low quality of evidence, downgraded for serious indirectness).3,4 In a newborn piglet model of hypoxic cardiac arrest, no difference was found in oxygenation among groups treated with 3 different types of respiratory support during CPR (T-piece, self-inflating bag, or mechanical ventilator).3 In another newborn piglet study using an asystolic CPA model, there was no difference in oxygenation among groups treated with 3 different types of respiratory support (T-piece vs rebreathing bag vs ventilator).4

Treatment recommendation

In dogs and cats that experience CPA while undergoing mechanical ventilation, we suggest switching to manual ventilation.(weak recommendation, expert opinion)

If delivering breaths by mechanical ventilator during CPR in dogs and cats, ventilator settings should be adjusted to assure breaths are delivered (e.g., volume control mode; TV 10 mL/kg; RR 10 / minute; PEEP 0 cmH2O; pressure limit 60 cmH2O; and a trigger sensitivity least likely to detect a breath [e.g., -10 cmH20]).(strong recommendation, very low quality of evidence)

Justification of treatment recommendation

The studies identified, both in newborn piglets, found no differences in the critical and important outcomes evaluated whether ventilation was provided with a mechanical ventilator or with manual ventilation. Given the time delay and possible errors introduced in adjusting a mechanical ventilator adequately for breath delivery during CPR, the committee believes that switching to a manual ventilatory device may be easier and more efficient. In addition, a study in pigs found that using clinically relevant patient trigger variables during CPR resulted in hyperventilation, lower minute ventilation, and poorer oxygenation compared to those achieved by disabling the trigger sensitivity or using a trigger setting of 20 cmH2O.[ 1988] These results suggest that it may be necessary to adjust ventilator settings to ensure appropriate respiratory support is provided during CPR. It is important to note that the application of positive end expiratory pressure (PEEP) during CPR could have negative hemodynamic effects and the optimal settings for PEEP during CPR are unknown.

Knowledge gaps

Comparisons of performing CPR using a mechanical ventilator versus manual ventilation in situations other than newborn piglet hypoxic models of CPA are lacking. The optimal mechanical ventilator settings for use during CPR are unknown, including the use of PEEP.