Perineural low dexamethasone dose as adjuvant in supraclavicular brachial plexus block for arteriovenous fistula creation in end stage renal disease: a randomized controlled trial

Abstract Background and aims: Dexamethasone as adjunct to local anesthetic solution improves the quality of brachial plexus block (BPB). However, evidence for its efficacy at low doses (< 4 mg) is lacking. This study was designed to evaluate the duration of analgesia attained with low dose dexamethasone as adjuvant to local anesthetic for creation of arteriovenous fistula (AVF) under BPB. Methods: Sixty-six patients scheduled for AVF creation were randomly allocated to receive either saline (control) or 2 mg dexamethasone, together with 0.5% ropivacaine and 0.2% lignocaine. The primary outcome was duration of analgesia, defined as time from performing the block to the first analgesic request. The secondary outcomes were time from injection to complete sensory block, time from injection to complete motor block, duration of motor block, postoperative analgesic consumption, and fistula patency at three months. Results: All the blocks were effective. In the group that received dexamethasone, the time to first analgesic request was significantly delayed (432 ± 43.8 minutes vs. 386.4 ± 40.2 minutes; p < 0.01). The onset of sensory and motor blockade occurred faster in dexamethasone group and overall analgesic consumption was also reduced. However, dexamethasone addition did not prolong the duration of motor block. There was no statistically significant difference in the patency of fistulas between the two groups at three months. (p = 0.34). Conclusion: Addition of low-dose perineural dexamethasone to local anesthetic solution significantly prolonged the duration of analgesia. Further trials are warranted to compare the adverse effects between dexamethasone doses of 4 mg and lower.

Lung ultrasonography as a tool to guide perioperative atelectasis treatment bundle in head and neck cancer patients undergoing free flap reconstructive surgeries: a preliminary observational study / Ultrassonografia pulmonar como ferramenta para orientar o tratamento perioperatório de atelectasia em pacientes com câncer de cabeça e pescoço submetidos a cirurgia reconstrutiva com retalho livre: um estudo observacional preliminar

Abstract Introduction: General anesthesia causes pulmonary atelectasis within few minutes of induction. This can have significant impact on postoperative outcome of cancer patients undergoing prolonged reconstructive surgeries. Objective: The purpose of this study was to evaluate the impact of sonographically detected perioperative atelectasis on the need for postoperative oxygen supplementation, bronchodilator therapy and assisted chest physiotherapy in patients undergoing free flap surgeries for head and neck carcinoma. Methods: Twenty eight head and neck cancer patients underwent bilateral pulmonary ultrasonographic assessments before and after lung surgery. Lung ultrasound scores, serum lactate, and PaO2/FiO2 ratio were measured both at the beginning and at end of the surgery. Patients were scanned in the supine position and the number of single and confluent B lines was noted. These values were correlated with the need for oxygen therapy, requirement of bronchodilators and total weaning time to predict the postoperative outcome. Other factors affecting weaning were also studied. Results: Among twenty eight patients, seven had mean lung ultrasound score of ≥10.5 which correlated with prolonged weaning time (144.56±33.5min vs. 66.7±15.7min; p = 0.005). The change in lung ultrasound score significantly correlated with change in PaO2/FiO2 ratio (r = −0.56, p = 0.03). Elevated total leukocyte count >8200 ΜL and serum lactate >2.1 mmoL/L also predicted prolonged postoperative mechanical ventilation. Conclusion: This preliminary study detected significant levels of perioperative atelectasis using point of care lung ultrasonography in head and neck cancer patients undergoing long duration surgical reconstructions. Higher lung ultrasound scores highlighted the need for frequent bronchodilator nebulizations as well as assisted chest physiotherapy and were associated with delayed weaning. We propose more frequent point of care lung ultrasonographic evaluations and use of recruitment maneuvers to reduce the impact of perioperative pulmonary atelectasis.

Resumo Introdução: A anestesia geral causa atelectasia pulmonar poucos minutos após sua indução. Isso pode ter um impacto significativo no resultado pós-operatório de pacientes com câncer submetidos a cirurgias reconstrutivas prolongadas. Objetivo: Avaliar o impacto das atelectasias perioperatórias detectadas por ultrassonografia na necessidade de suplementação pós-operatória de oxigênio, terapia broncodilatadora e fisioterapia respiratória assistida em pacientes com carcinoma de cabeça e pescoço submetidos a cirurgias com uso de retalho livre. Método: Foram submetidos a avaliações ultrassonográficas pulmonares bilaterais antes e após a cirurgia 28 pacientes com câncer de cabeça e pescoço. Os escores de ultrassonografia pulmonar, lactato sérico, razão PaO2/FiO2 foram medidos no início e no fim da cirurgia. Os pacientes foram avaliados na posição supina e o número de linhas B confluentes e únicas foi observado. Esses valores foram correlacionados com a necessidade de oxigenoterapia, necessidade de broncodilatadores e tempo total de desmame para predizer o resultado pós-operatório. Outros fatores que afetam o desmame também foram estudados. Resultados: Entre os 28 pacientes, sete apresentaram escore médio de ultrassonografia pulmonar ≥ 10,5, que se correlacionou com o tempo de desmame prolongado (144,56 ± 33,5 minutos vs. 66,7 ± 15,7 minutos; p = 0,005). A mudança no escore de ultrassonografia pulmonar correlacionou-se significantemente com a mudança na razão PaO2/FiO2 (r = −0,56, p = 0,03). A contagem total elevada de leucócitos > 8200 uLe o nível de lactato sérico >2,1 mmoL/L também previram ventilação mecânica pós-operatória prolongada. Conclusão: Este estudo preliminar detectou um nível significante de atelectasia perioperatória com ultrassonografia pulmonar no local de atendimento em pacientes com câncer de cabeça e pescoço submetidos a reconstruções cirúrgicas de longa duração. Escores mais altos de ultrassonografia pulmonar enfatizaram a necessidade de nebulizações broncodilatadoras frequentes e fisioterapia respiratória assistida e foram associados a desmame tardio. Propomos avaliações ultrassonográficas pulmonares mais frequentes no local de atendimento e o uso de manobras de recrutamento para reduzir o impacto das atelectasias pulmonares perioperatórias.