Analysis of risk factors for venous air embolism in the semisitting position and its impact on outcome in a consecutive series of 740 patients

The semi-sitting position in patients with indwelling CSF shunts: perioperative management and avoidance of complications

OBJECTIVE

Posterior fossa or midline tumors are often associated with hydrocephalus and primary tumor removal with or without perioperative placement of an external ventricular drain (EVD) is commonly accepted as first-line treatment. Shunting prior to posterior fossa surgery (PFS) is mostly reserved for symptomatic cases or special circumstances. There are limited data regarding the anticipated risk for symptomatic pneumocephalus and the perioperative management using the semi-sitting position (SSP) in such a scenario. Here, we therefore assessed the safety of performing PFS in a consecutive series of patients over a period of 15 years to allow the elaboration of recommendations for perioperative management.

METHODS

According to specific inclusion and exclusion criteria a total of 13 patients who underwent 17 operations was identified. Supratentorial pneumocephalus was evaluated with semiautomatic-volumetric segmentation. The volume of pneumocephalus was evaluated according to age and ventricular size.

RESULTS

Ten of the 13 patients had a programmable valve (preoperative valve setting range 6-14 cmH20; mean 7.5 cmH20) while 3 patients had non programmable valves. A variable amount of supratentorial air collection was evident in all patients postoperatively (range 3.2-331 ml; mean 122.32 ml). Positive predictors for the volume of postoperative pneumocephalus were higher age and a preoperative Evans ratio > 0.3. In our series, we encountered no cases of tension pneumocephalus necessitating an air replacement procedure as well as no obstruction, disconnection, infection or hardware malfunction of the shunt system.

CONCLUSIONS

Our findings indicate that a CSF shunt in situ is not a contraindication for performing PFS in the semi-sitting position and it does not increase the pre-existing risk for postoperative tension pneumocephalus. In cases of primary shunting for hydrocephalus associated with posterior fossa tumors a programmable valve set at a medium opening pressure with a gravitational device is a valid option when PFS in the semi-sitting position is opted. In patients with an indwelling shunt diversion system special caution is indicated in order to prevent and detect overdrainage especially in not adjustable valves or shunts without antisiphon devices.

Thrombotic pulmonary embolism of inferior vena cava during caesarean section: A case report and review of the literature

BACKGROUND

Thrombotic pulmonary embolism (TPE) is one of the most critical diseases in obstetrics but is rarely reported in caesarean section (CS) because TPE patients in CS have a high risk of death and are difficult to diagnose. This case report of TPE during CS was recorded by transthoracic echocardiography (TTE) and can provide a reference for the differential diagnosis of critical illnesses in CS.

CASE SUMMARY

A 37-year-old pregnant woman with rheumatic heart disease (RHD), gravida 5 and para 1 (G5P1), presented for emergency CS at 33 wk and 3 d of gestation under general anesthesia because of acute heart failure, pulmonary hypertension and arrhythmia. After placental removal during CS, TTE revealed a nascent thrombus in the inferior vena cava (IVC) that elongated, detached and fragmented leading to acute thromboembolic events and acute TPE. This report presents the whole process and details of TPE during CS and successful rescue without any sequelae in the patient. This case gives us new ideas for the diagnosis of death or cardiovascular accidents during CS in pregnant women with heart disease and the detailed presentation of the rapid development of TPE may also elucidate new ideas for treatment. This case also highlighted the importance of prophylactic anticoagulation in the management of heart disease during pregnancy.

CONCLUSION

Pregnancy with heart failure could trigger inferior vena cava (IVC)-origin TPE during CS. Detection and timely treatment can avoid serious consequences.