Document: Invite

Comments:

BLS-13-v1

RECOVER 2.0 Worksheet

QUESTION ID: BLS-13

PICO Question:
In cats and dogs in CPA (P), does providing ventilation with other inspiratory times and tidal volumes (I), compared with with a 1-second inspiratory time and tidal volume of about 10 mL/kg (C), improve ... (O)?

Outcomes:
Favorable neurologic outcome, PaCO2, Oxygenation, Surrogate marker(s) of perfusion, Survival to discharge, ROSC

Prioritized Outcomes (1= most critical; final number = least important):

Favorable neurologic outcome
Survival to discharge
ROSC
PaCO2
Oxygenation
Surrogate markers of perfusion

Domain chairs: Steve Epstein, Kate Hopper; final edit by Jamie Burkitt

Evidence evaluators: Heike Botha, Guillaume Hoareau

Conflicts of interest: None reported

Search strategy: See attached document

Evidence Review:

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: Favorable Neurological Outcome

- -

One experimental swine study found no difference in neurological outcome at 24 hrs between a TV of 10ml/kg at 10pbm vs a TV of 20 ml/kg at 35 bpm (no I-time described)

very low

Outcome: Survival to discharge

- -

One experimental swine study found no difference in neurological outcome at 24 hrs between a TV of 10ml/kg at 10pbm vs a TV of 20 ml/kg at 35 bpm (no I-time described)

very low

Outcome: ROSC
3	EX	0	- -	-	0	0	0	0	Three experimental swine study found no difference regardless of TV evaluated	very low
Outcome: PaCO2
3	EX	0	- -	-	0	0	0	0	Three experimental swine studies found no difference in PaCO2 regardless of TV evaluated	very low

Outcome: Oxygenation

- -

One experimental swine study found PaO2 was higher with 10mlkg TV (~17bpm) vs 7ml/kg TV (10 bpm). The remaining two studies found no difference

very low

Outcome: Surrogate markers of perfusion

- -

Three experimental swine study found no difference regardless of TV evaluated

very low

PICO Question Summary

Introduction

The optimal tidal volume and inspiratory time during ventilation in CPR would generate an appropriate PaCO2 and oxygenation while minimizing the negative cardiovascular effects of positive pressure ventilation. The current human guidelines for CPR generally recommend a tidal volume of 6 - 7 mL/kg (up to 10 mL/kg in some circumstances) and an inspiratory time of 1 second.1 The previous veterinary guidelines recommend a tidal volume of 10 mL/kg and an inspiratory time of 1 second.2 These recommendations were based on a limited body of evidence and equipoise remains.

Consensus on science

Outcome 1: Favorable neurologic outcome

For the most critical outcome of favorable neurologic outcome, we identified 1 experimental VF study in swine that addresses the PICO question (very low quality of evidence downgraded for very serious indirectness and serious imprecision).3 This study found no difference in neurological outcome at 24 hours when comparing a tidal volume (TV) of 10mL/kg at 10 breaths per minute (bpm) to a TV of 20 mL/kg at 35 bpm; inspiratory time (I-time) was not described.3

Outcome 2: Survival to discharge

For the next critical outcome of Survival to discharge, we identified 1 experimental VF study in swine that addresses the PICO question (very low quality of evidence downgraded for very serious indirectness and serious imprecision).3 This study found no difference in survival at 24 hours when comparing a TV of 10mL/kg at 10 bpm to a TV of 20 mL/kg at 35 bpm; I-time was not described.3

Outcome 3: ROSC

For the next critical outcome of ROSC, we identified 3 experimental VF studies in swine that address the PICO question (very low quality of evidence downgraded for very serious indirectness and serious imprecision). 3–5 One study compares a TV of 10 mL/kg at 10 bpm to a TV of 20 mL/kg at 35 bpm (I-time not described) 3; 1 study compares a TV of 10 mL/kg at baseline RR (~17 bpm) to a TV of 7 mL/kg at 10 bpm, both with a 2-second I-timeC; and the final study compares a TV of 8-9 mL/kg at 10 bpm to a TV of 2-3 mL/kg at 50 bpm (I-time not described)5. No study found a difference in ROSC between respective treatment groups. 3–5

Outcome 4: PaCO2

For the important outcome of PaCO2, we identified 3 experimental VF studies in swine that address the PICO question (very low quality of evidence downgraded for very serious indirectness and serious imprecision). 3–5 One study compares a TV of 10 mL/kg at 10 bpm to a TV of 20 mL/kg at 35 bpm (I-time not described)3; 1 study compares a TV of 10 mL/kg at baseline RR (~17 bpm) to a TV of 7 mL/kg at 10 bpm, both with a 2-second I-time4; and the final study compares a TV of 8-9 mL/kg at 10 bpm to a TV of 2-3 mL/kg at 50 bpm (I-time not described) 5. No study found a difference in PaCO2 between respective treatment groups. 3–5

Outcome 5: Oxygenation

For the important outcome of oxygenation, we identified 3 experimental VF studies in swine that address the PICO question (very low quality of evidence downgraded for very serious indirectness and serious imprecision). 3–5 One study found PaO2 was higher with a 10 mL/kg TV delivered at a baseline RR (~ 17 bpm) vs a 7 mL/kg TV at 10 bpm, both with 2-second I-times.4 The remaining 2 studies found no difference in PaO2 when comparing a TV of 10 mL/kg at 10 bpm to a TV of 20 mL/kg at 35 bpm (I-time not described) 3 or a TV of 8-9 mL/kg at 10 bpm to a TV of 2-3 mL/kg at 50 bpm (I-time not described).5

Outcome 6: Surrogate markers of perfusion

For the important outcome of Surrogate markers of perfusion, we identified 3 experimental VF studies in swine that address the PICO question (very low quality of evidence downgraded for very serious indirectness and serious imprecision).3–5 One study compares a TV of 10 mL/kg at 10 bpm to a TV of 20 mL/kg at 35 bpm (I-time not described)3; 1 study compares a TV of 10 mL/kg at baseline RR (~17 bpm) to a TV of 7 mL/kg at 10 bpm, both with a 2-second I-time4; and the final study compares a TV of 8-9 mL/kg at 10 bpm to a TV of 2-3 mL/kg at 50 bpm (I-time not described)5. No study found a difference in hemodynamic parameters between respective treatment groups.3–5

Treatment recommendation

We recommend administering positive pressure ventilation at a tidal volume of 10 mL/kg and a 1-second inspiratory time during CPR in intubated dogs and cats.(strong recommendation, very low quality of evidence)

Justification of treatment recommendation

The evidence identified found a tidal volume of ~10 mL/kg had similar outcomes to several other tidal volumes evaluated. Overall, this treatment recommendation is based on a very low level of evidence that failed to identify a superior option. Inspiratory time is very poorly evaluated in the literature and the treatment recommendation is based on common clinical practice and previous consensus statements.

Knowledge gaps

Further studies are necessary to determine the ideal inspiratory time and tidal volume in intubated dogs and cats during CPA.

Limited studies exist investigating varied tidal volumes; however, inspiratory time is frequently not mentioned and no studies evaluating varying inspiratory times were found.

References:

1. Panchal AR, Bartos JA, Cabañas JG, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020;142(16_suppl_2):S366-S468.

2. Fletcher DJ, Boller M, Brainard BM, et al. RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 7: Clinical guidelines: RECOVER clinical guidelines. J Vet Emerg Crit Care. 2012;22(s1):S102-S131.

3. Hayes MM, Ewy GA, Anavy ND, et al. Continuous passive oxygen insufflation results in a similar outcome to positive pressure ventilation in a swine model of out-of-hospital ventricular fibrillation. Resuscitation. 2007;74(2):357-365.

4. Tan D, Sun J, Geng P, et al. Duration of cardiac arrest requires different ventilation volumes during cardiopulmonary resuscitation in a pig model. J Clin Monit Comput. Published online 2019.

5. Ruemmler R, Ziebart A, Moellmann C, et al. Ultra-low tidal volume ventilation-A novel and effective ventilation strategy during experimental cardiopulmonary resuscitation. Resuscitation. 2018;132:56-62.

Supplemental:

258: Hayes 2007 – 36 Swine (12/group: 10mL/kg at 10bpm, 20 mL/kg at 35 bpm, no IPPV groups), VF, 8-minute downtime prior to any intervention

264: Tan 2019 – 32 swine (16 4-min VF downtime, 16 8-min VF downtime), randomized to 7mL/kg at 10bpm v 10mL/kg at baseline RR – appx 17 bpm - (all 2-sec I-time).

276: Ruemmler 2018 – 30 swine in 4-minute VF downtime, randomized (10/ group: 2-3 mL/kg at 50 bpm v 8-9mL/kg at 10 bpm vs no IPPV)

DMU Timestamp: July 13, 2023 21:18