Adherence to calcium channel blocker poisoning treatment recommendations in two Canadian cities

No study has documented whether physicians call poison control centres (PCC) for calcium channel blocker (CCB) poisoning or if interventions suggested by the PCC are being applied.

This study evaluated the compliance of physicians with the Quebec Poison Control Center's (QPCC) recommendations for the treatment of CCB poisoning. It also assessed the outcomes of these patients.

This retrospective chart review was conducted with CCB-poisoned adults who were admitted to a hospital in Quebec City or Montreal between January 2004 and November 2007. Using the sequence of interventions, it was determined whether or not the PPC recommendations were adhered to. Level of care provided, morbidity and mortality were reported. The researchers also used the QPCC database to verify if the poison centre was consulted for the care of the patient.

A total of 103 cases were identified. 42% (43/103) were classified as compliant (all PCC recommendations were followed) and 58% (60/103) non-compliant group (some or no PCC recommendations followed). The poison control centre (PCC) was contacted for 74% of the total cases (81% of cases in the compliant group and 68% in the non-compliant group). High-dose insulin euglycemia therapy (HIET) was not started when indicated or started at too low dosage in 20 cases. Glucagon was given, even if not indicated, in 14 cases and decontamination was inappropriate in at least 10 cases. For the entire sample, there was an average of 8 days of hospitalization, 47 h of intensive care, 11 h of vasopressor use, a morbidity of 50% and a mortality of 6%. Acute renal failure (35%), metabolic acidosis (25%), acute pulmonary oedema (15%), aspiration pneumonia (15%), rhabdomyolysis (8%), myocardial ischemia (7%), abnormal liver function tests (AST/ALT) (6%), cerebral anoxia (4%) and ileus (3%) were among the most frequent complications. The outcomes in the non-compliant group versus the compliant group showed a mortality of 10% versus 0% (95%CI 0.00-0.20, p-value < 0.0001), a morbidity 67% versus 26% (95%CI 0.17-0.57, p-value < 0.0001) (OR 0.21 unadjusted and 0.64 adjusted, p-value < 0.0001), a median hospital length of stay (LOS) of 5 days versus 1 da y (p-value < 0.0001) (OR of a LOS ≥ 1 day 0.23 unadjusted and 0.39 adjusted, p-value < 0.0001), a median ICU LOS of 34 h versus 0 h (p-value < 0.0001) (OR of a ICU LOS ≥ 1 day 0.16 unadjusted and 0.38 adjusted, p-value < 0.0001) and a median duration of vasopressor of 17 h versus 3 h (p-value 0.0002) (OR of a vasopressor ≥ 1 h 0.15 unadjusted and 0.29 adjusted, p-value < 0.0001).

In conclusion, the majority of the physicians did not follow PCC recommendations for the treatment of CCB poisoning. Further studies are ongoing as to evaluate the barriers to protocol adherence and to develop evidence based guidelines accompanied by an effective implementation strategy.