Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27 × 10e-4 (according to official data of new cases diagnosed by PCR) to 4.69 × 10e-4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence. / Utilidad de la prueba de reacción en cadena de la polimerasa preoperatoria durante la pandemia por SARS-CoV-2: el desafío de la incidencia cambiante.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27*10e -4 (according to official data of new cases diagnosed by PCR) to 4.69*10e -4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

Anaesthetic management in thoracoscopic distal tracheal resection. / Manejo anestésico en la resección traqueal distal toracoscópica.

Surgical resection of tracheal tumours, especially distal tracheal tumours, is a challenge for the anaesthesiologists involved, mainly due to difficulties in ensuring adequate control of the airway and ventilation. We report the case of a patient undergoing tracheal resection and anastomosis by VATS, emphasizing the anaesthetic management.

[Perioperative treatment for the urgent orbital decompression surgery in a 30-weeks pregnant woman with Graves' orbitopathy]. / Tratamiento perioperatorio para la cirugía urgente de descompresión orbitaria en una paciente gestante de 30 semanas con orbitopatía de Graves.

Thyroid ophthalmopathy is a rare extra-thyroid complication usually associated with Graves' disease. This disease can occur in the euthyroid pregnant patient. Graves' orbitopathy is characterized by eyelid retraction, proptosis, extraocular muscle dysfunction, and periorbital edema. In some cases an emergency surgical repair may be required to avoid irreversible vision loss. We present the case of a 35-year-old woman in her 30th gestational week, who suffered from Graves' ophthalmopathy, severe exophthalmia, and visual acuity decrease. Following consultations among anesthesiologists, ophthalmologists, maxillofacial surgeons, endocrinologists, obstetricians and the patient, it was decided to perform a surgical orbital wall decompression. The anesthetic and perioperative implications associated with gestational age and the considerations for this surgical procedure, and how to avoid increasing intraocular pressure are discussed.