16 Study Design

17 Reduced Quality Factors

18 0 = no serious, - = serious,

19 - - = very serious

20 Positive Quality Factors

21 0 = none, + = one, ++ = multiple

22 Dichotomous Outcome Summary

23 Non-Dichotomous Outcome Summary

24 Brief description

25 Overall Quality

26 High, moderate, low,
very low, none

27 No of studies

28 Study Type

29 RoB

30 Indirectness

31 Imprecision

32 Inconsistency

33 Large Effect

34 Dose-Response

35 Confounder

36 # Intervention with Outcome

37 # Control with Outcome

38 RR (95% CI)

39 Outcome 1: Favorable neurologic outcome

40 1

41 OB

42 0

43 - -

44 -

45 0

46 Very low

47 Outcome 2: Survival discharge

48 6

49 OB

50 0

51 - -

52 -

53 0

54 Very low

55 Outcome 3: ROSC

56 4

57 OB

58 0

59 - -

60 -

61 0

62 Very low

63 Outcome 4: Time to start CPR

64 1

65 CT

66 -

67 -

68 0

69 0

70 Very low

71 1

72 OB

73 -

74 -

75 0

76 0

77 Very low

78 1

79 Exp

80 0

81 --

82 -

83 0

84 Very low

85 Outcome 5: Time to identify CPA

86 14

87 OB

88 -

89 -

90 0

91 0

92 4

93 EXP

95 Introduction

96 Continuous ECG monitoring may be observed directly or remotely and can alert nurses and doctors to the presence of arrhythmias that may be associated with CPA. Because ECG devices and monitoring capability can be limited in some hospitals, this query was designed to determine if ECG monitoring in patients at risk of CPA affected the outcomes of interest.

97 Consensus on science

98 Outcome 1: Favorable neurologic outcome

99 For the most critical outcome of favorable neurologic outcome, 1 retrospective, registry-based observational study in people was identified that addressed the PICO question (very low quality of evidence, downgraded for very serious indirectness and imprecision).1 In 6789 patients who developed CPA due to a shockable arrest rhythm, the adjusted odds ratio for FNO among patients defibrillated more than 2 minutes after developing CPA was 0.74 (95% CI = 0.56–0.96, P = 0.02). Additionally, the odds ratio for delayed defibrillation in patients managed in an inpatient unit with telemetry was 0.47 (95% CI = 0.41–0.53, P < 0.001). These data suggest that patients with continuous telemetry-based ECG monitoring were more likely to have prompt defibrillation and improved FNO.

100 Outcome 2: Survival to discharge

101 For the next most critical outcome of survival to discharge, 6 observational studies in people were identified that addressed the PICO question (very low quality of evidence, downgraded for very serious indirectness and serious imprecision).1–6 In human hospitals, hospitalization in an unmonitored ward is associated with lower frequency of survival to discharge after IHCA.1,2 One particular at-risk group that experienced IHCA secondary to aspiration pneumonia had a lower frequency of survival to discharge when CPA occurred in an unmonitored area.2 The primary factor leading to continuous monitoring in human patients was ongoing myocardial infarction, which may limit the applicability of these findings to dogs and cats.3 These studies did not directly compare ECG monitoring to no ECG monitoring however, and most patients with ECG monitoring were housed in wards with nurses with more expertise caring for higher acuity patients. Other studies in people support an increased chance of survival to hospital discharge following IHCA and resuscitation in patients housed in areas that are better monitored (including, but not limited to continuous ECG) compared to IHCA in locations where the level of monitoring was lower and continuous ECG-monitoring absent.3–5 Two observational studies found that continuous ECG monitoring by a central station did not improve survival to discharge following IHCA.6,7 The Mohammed (2015) study specifically evaluated the use of continuous telemetry monitoring in non-critically ill patients.6 The variability of quality of CPR is not directly addressed in these studies, although the location of many monitored patients in higher acuity wards likely results in some bias regarding familiarity of the attending nurses and physicians with CPR protocol.

102 Outcome 3: ROSC

103 Four observational studies in people were identified that informed the answer to this PICO question for this outcome (very low quality of evidence, downgraded for very serious indirectness and serious imprecision).1,2,6,7 Two observational studies in people specifically evaluated ECG monitoring and ROSC for IHCA, finding that continuous ECG monitoring was associated with an increased frequency of ROSC.1,7 In addition, one observational study in people evaluating patients with aspiration pneumonia compared to patients with respiratory failure due to other causes found that the latter group was more frequently monitored with continuous ECG and had a higher frequency of ROSC than patients with aspiration pneumonia.2 Only one observational study in non-critically ill patients found no effect of continuous monitoring with telemetry on ROSC.6

104 Outcomes 4 and 5: Time to start CPR, Time to identify CPA

105 Because substantial evidence was available to inform an answer to this PICO question for the 3 most critical outcomes, only a cursory evaluation of the literature for the 2 least critical outcomes was done. Many of the studies cited above also demonstrated decreased time to diagnosing CPA and initiating BLS and ALS interventions in patients with continuous ECG monitoring.1,2,4 In pediatric populations, however, ECG monitoring may not reliably identify all CPA events. In one study, children with an arrest rhythm of PEA experienced a significant delay from onset of CPA to start of CPR compared to infants with ECG diagnoses of either bradycardia or ventricular fibrillation.8,9 In experimental studies in dogs subjected to uncoupling of electrical and mechanical heart function and pigs subjected to asphyxial arrest, the ECG indicated either no change or bradyarrhythmias for a period of time (4-6 minutes) without a perfusing rhythm, highlighting the major problem with sole reliance on ECG monitoring to diagnose CPA in certain scenarios.10,11 In a study of pediatric CPA, other monitored parameters such as blood pressure and pulse oximetry more accurately diagnosed CPA than the ECG.8 However, another study showed that diagnosis of bradycardia in pre-term infants was slower with a pulse oximeter than an ECG.12

106 Treatment recommendation

107 We recommend continuous ECG monitoring in dogs and cats at risk of CPA (e.g., under anesthesia, in shock, in respiratory distress, post-ROSC, aspiration risk). (strong recommendation, very low quality of evidence)

108 Justification of treatment recommendation

109 Although much of it is indirect, there is substantial evidence of better outcomes in patients with IHCA that have continuous ECG monitoring in place at the time of the arrest. However, ECG monitoring alone is not adequate to diagnose CPA in patients with PEA or pulseless VT, and other monitoring (such as arterial blood pressure, pulse oximetry, and end tidal CO2 monitoring) may provide important additional information to increase the sensitivity of the monitoring plan for CPA.

110 Knowledge gaps

111 There are no veterinary studies in hospitalized dogs and cats investigating the utility of ECG monitoring for the diagnosis of CPA in at-risk populations. In addition, there are limited data available to inform the decision of which patients would benefit most from continuous ECG monitoring.