Local anaesthetic systemic toxicity complicating intraoperative intercostal nerve blocks: What do clinicians need to know to prevent similar occurrence?

Local anaesthetic systemic toxicity is a life-threatening adverse event that may occur after administration of local anaesthetics through a variety of routes. Local anaesthetic systemic toxicity is always a potential complication and may occur with all local anaesthetics and in any route of administration. Local anaesthetic systemic toxicity primarily affects the central nervous system and the cardiovascular system and may be fatal. The following is a case of local anaesthetic systemic toxicity complicating surgeon-performed intraoperative intercostal nerve blocks at multiple levels, with a mixture of liposomal bupivacaine and bupivacaine hydrochloride in a patient who underwent video-assisted segmental lung resection for lung cancer under general anaesthesia. Local anaesthetic systemic toxicity presented with seizures and hypotension. The patient was successfully managed and fully recovered. This case illustrates the importance of awareness regarding the prevention, diagnosis and treatment of local anaesthetic systemic toxicity among medical professionals who administer local anaesthetics.

Ventral hernia repair with synthetic mesh in a contaminated field: a systematic review and meta-analysis

PURPOSE

The use of mesh in ventral hernia repair becomes especially challenging when associated with a contaminated field. Permanent synthetic mesh use in this setting is currently debated and this discussion is yet to be resolved clinically or in the literature. We aim to systematically assess postoperative outcomes of non-absorbable synthetic mesh (NASM) used in ventral hernia repair in the setting of contamination.

METHODS

A literature search of PubMed, Embase, Scopus, Cinahl, and Cochrane Library identified all articles from 2000-2020 that examined the use of NASM for ventral hernia repair in a contaminated field. Postoperative outcomes were assessed by means of pooled analysis and meta-analysis. Qualitative analysis was completed for all included studies using a modified Newcastle-Ottawa scale.

RESULTS

Of 630 distinct publications and 104 requiring full review, this study included 17 articles published between 2007 and 2020. Meta-analysis demonstrated absorbable mesh was associated with more HR (OR 1.89, 1.15-3.12, p = 0.008), SSO (OR 1.43, 0.96-2.11, p = 0.087), SSI (OR 2.84, 1.85-4.35, p < 0.001), and unplanned reoperation (OR 1.99, 1.19-3.32, p = 0.009) compared to NASM.

CONCLUSION

The use of NASM for ventral hernia repair in a contaminated field may be a safe alternative to absorbable mesh, as evidenced by lower rates of postoperative complications. This review counters the current clinical paradigm, and additional prospective randomized controlled trials are warranted.

Postoperative Serotonin Syndrome Following Methylene Blue Administration for Vasoplegia After Cardiac Surgery: A Case Report and Review of the Literature

Serotonin syndrome is a potentially life-threatening condition associated with increased serotonergic activity in the central nervous system. The increasing incidence of this condition is thought to parallel the increasing use of serotonergic agents in medical practice. The selective serotonin reuptake inhibitors are perhaps the most commonly implicated group of medications associated with serotonin syndrome. This case report describes the occurrence of postoperative serotonin syndrome in a patient on long-term sertraline who underwent coronary artery bypass graft and was treated with methylene blue for perioperative vasoplegia. It delineates the various clinical features commonly encountered and illustrates the recommended management modalities, including prevention, for this potentially lethal medical emergency. With prompt diagnosis and expeditious treatment, the patient has had full recovery.

Progressive anterior ablation in the coronary sinus region: evidence to support the presence of a 'slow pathway' input in normal patients?

BACKGROUND

AV node modification is an emerging approach to rate control in patients with medically refractory atrial fibrillation. The mechanism of benefit of this procedure is not completely understood.

METHODS AND RESULTS

Twenty-two patients (age, 65+/-11 years; 16 women) with medically refractory paroxysmal atrial fibrillation referred for complete AV node ablation underwent serial ablations beginning at the level of the coronary sinus os progressing in a superior and anterior direction toward the His bundle. Serial atrial extrastimulus testing was performed to determine the effect of the progressive posteroseptal ablation in the region of the coronary sinus on the AV node antegrade refractory curve. Two of 22 patients had antegrade dual AV node pathways before ablation. Three patterns of response to serial ablation were noted. In 10 patients (45%), loss of the terminal portion of the AV node antegrade refractory curve occurred without evidence of fast pathway injury. In 7 patients (32%) the curve was shifted upward and to the left, consistent with nonspecific AV node damage. In 5 patients (23%), no effect could be attained before induction of complete AV block at superior and anterior ablation sites. Clinical variables and site of ablation did not predict response to serial ablations.

CONCLUSIONS

These data suggest that the mechanism of benefit of AV node modification in this population may be through elimination of "slow pathway" tissue in half of patients and nonspecific injury in the remainder. Modification without complete AV block may not be possible in a minority of patients, as the response to progressive ablation appears to be "all or none" conduction.

Safety of slow pathway ablation in patients with atrioventricular node reentrant tachycardia and a long fast pathway effective refractory period

Radiofrequency catheter ablation is an accepted primary therapy for atrioventricular (AV) node reentrant tachycardia (AVNRT). There is concern that slow pathway ablation in patients with a long anterograde fast pathway effective refractory period (ERP) may potentially impair subsequent node conduction. Eighteen patients (14 women; age 53 +/- 20 years) with symptomatic AVNRT, whose fast pathway ERP at baseline was > or = 500 ms, underwent slow pathway ablation. Their outcome was compared with 24 consecutive control patients (17 women; age 42 +/- 17 years) who underwent ablation for AVNRT whose fast pathway ERP at baseline was <500 ms (controls). Slow pathway ablation was successful in 16 patients (90%). One patient had inadvertent fast pathway ablation. In a second patient the slow pathway could not be ablated because of recurrent transient AV block. Ablation was successful in all patients in the control group. Transient AV block related to current application occurred in 4 patients (22%) versus 1 control (4%) (p = 0.07). After ablation, the AV node refractory period increased in patients (368 +/- 68 to 428 +/- 92 ms, p = 0.02) and in controls (282 +/- 35 to 336 +/- 55 ms, p <0.0001), but the fast pathway ERP shortened in both groups (patients: 558 +/- 63 to 428 +/- 92 ms, p = 0.003; controls: 356 +/- 53 to 336 +/- 55 ms, p = 0.05). Furthermore, the slope of the regression line relating to shortening of the fast pathway ERP to the baseline ERP was markedly steeper in patients compared with controls (1.9 vs 0.4, p <0.0001). The shortening of the fast pathway ERP was greater in patients compared with controls (122 +/- 130 vs 21 +/- 50 ms, p = 0.001). During a mean follow-up of 18 +/- 11 months, 1 patient with severe coronary artery disease died suddenly 2 years after ablation. There was no recurrence of clinical tachycardia, and none of the patients developed symptoms of bradycardia or required permanent pacing. Thus, slow pathway ablation in patients with AVNRT and a long fast pathway ERP is safe and effective.

Sotalol proarrhythmia: a report of five cases and an audit of the use of a sotalol in a teaching hospital

BACKGROUND

Polymorphic ventricular tachycardia is an uncommon complication of sotalol use.

AIMS

The aims of this study were: (1) to report five cases of sotalol proarrhythmia and (2) to audit the use of sotalol in a teaching hospital population.

METHODS

Five patients with sotalol proarrhythmia (defined as new ventricular arrhythmias associated with sotalol administration) were identified over an 18 month period. Sotalol use for patients admitted to the John Hunter Hospital was audited over a six month period with 85 patients (55 males) identified from the pharmacy database. Medical records were reviewed and the details of treatment including sotalol dose and indication determined. Creatinine clearance was estimated by the Cockcroft and Gault regression equation.

RESULTS

The audit indicated that sotalol was prescribed predominantly for management of atrial arrhythmias (80%). Paroxysmal atrial fibrillation was the most common indication (71%). Although female patients were older (72 +/- 13 vs 62 +/- 15 years, p < 0.001) and had a lower creatinine clearance (55 +/- = 24 vs 82 +/- = 32 mg/minute, p < 0.001) than male patients, they were prescribed similar doses of sotalol (206 +/- 112 vs 193 +/- 93 mg/day). The ratio of sotalol dose to creatinine clearance was higher in female patients (4.0 +/- 2.6 vs 2.16 +/- 1.5, p < 0.01). The five patients with proarrhythmia (torsades de pointes in four patients and polymorphic ventricular tachycardia in one patient) were all female. Daily sotalol dose (odds ratio for each 160 mg tablet 4.9 [95% confidence interval 1.5-16] and female gender (p < 0.01) were significant risk factors for proarrhythmia.

CONCLUSION

Sotalol dose was not appropriately adjusted for creatinine clearance which is age and gender dependent. Female patients have an increased risk of proarrhythmia and should receive lower doses of sotalol.