Coiled central venous catheter in superior vena cava

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Sir, Central venous pressure (CVP) monitoring is a simple, relatively inexpensive method of assessing a patient's circulating blood volume, cardiac status and vasomotor tone. It is essential to be aware of the inherent fallacies and inadequacies of the information derived. Inaccurate measurements are often obtained by the aberrant lodgement of the central venous catheter (CVC) tip.
In continuation of the previously published letter to editor concerning misdirected CVC, we describe an unusual case of CVC coiling in the superior vena cava (SVC) leading to falsely high CVP measurement. A 55 year old male patient was brought to the emergency room (ER) with head injury, blunt trauma abdomen with haemodynamic instability. He was further posted for an emergency laparotomy. In view of the clinical condition of the patient and the need to know intravascular volume status, a 7 French triple lumen CVC was inserted in the right internal jugular vein (IJV) in the operating room (OR). All the three ports were checked for free flow of blood and the CVC was fixed at 11cm at skin level. On connecting the transducer to the monitor, ideal waveform was absent. Intra operatively CVP tracing was suboptimal despite the change of transducer, the cable, flushing the unit and repeated zeroing. Post operatively the patient was shifted to intensive care unit on ventilator support for further management. Chest radiograph revealed coiled CVC in the SVC [ Figure 1]. Hence it was removed and right subclavian vein was cannulated.
The correct placement of the CVC tip is an important factor in obtaining accurate CVP measurements. Malposition of a CVC may occur at the time of insertion or later as a result of spontaneous migration due to anatomic positioning or pressure changes within the thoracic cavity. [1] There has been case report on CVC folding back during guide-wire removal inside IJV. [2] In our case CVC coiling inside SVC was unusual as it is a large calibre vessel with high flows. There was no anatomical vascular abnormality and no manufacturing defect in CVC. The abutting of the guide wire against the wall of the SVC probably caused the coiling of CVC in the SVC. The J tip of guide wire probably was unknowingly directed cephalad while insertion, which could have caused CVC to further angulate in the upward direction over the guide wire.
In conclusion, inaccurate CVP measurements or inability to obtain an ideal wave from tracing are suggestive of an undesirable location of the catheter tip. Awareness of this possibility and careful review of the CVC tip position on X-ray pictures in suspicious cases are important. Inaccurate CVP readings lead to improper assessment of the intravascular status of the patient. Careful clinical co-relation under such circumstances is essential. Roentgenograms after insertion of CVC are essential to eliminate this problem, which is often encountered in clinical practice. Sir,

Brief Communications
Dysrhythmias are well known and not of uncommon occurrence in neurosurgical procedures. [1] The proximity of the surgical site to vital centers and initiation of trigemino-cardiac reflex (TCR) is often implicated. Hydrogen peroxide irrigation is commonly performed to clean the surgical wound and achieve haemostasis. The use of hydrogen peroxide is also not without haemodynamic complications. [2] We report a case of a female undergoing surgery for pituitary tumour who suffered dysrhythmias both during manipulation of the tumour, as a result of TCR and at the time of irrigation of hydrogen peroxide.
A 16-year-old female was admitted to our neurosurgical unit with presenting complaint of acromegalic features. Magnetic resonance image (MRI) of the head revealed a 5.2 × 3.2 × 4.5 cm lesion in the sellar extending to suprasellar region, suggestive of pituitary tumour. The patient was scheduled for elective craniotomy and tumour resection. The patient was premedicated with intramuscular glycopyrrolate 0.2 mg, one hour prior to surgery. General anaesthesia was induced with fentanyl 2 mcg/kg and thiopentone 4-5 mg/kg. Tracheal intubation was facilitated with rocuronium 1 mg/kg. An arterial line was placed in the dorsalis pedis artery of left foot. Anaesthesia was maintained with isoflurane (MAC~ 1 ± 0.2) in a mixture of O 2 and N 2 O (1:2). At the time of tumour resection, there occurred sudden bradycardia and hypotension. There was decrease in heart rate from 70 beats per minute (bpm) to 52 bpm and blood pressure dropped from 110/76 to 68/45 mmHg. The surgeon was immediately informed. No sooner the surgical stimulus stopped, the heart rate and blood pressure reached the pre-stimulus values. Surgery was allowed to continue. To achieve complete haemostasis, the surgeon irrigated the surgical wound with 10 ml of diluted 3% hydrogen peroxide solution (1:1). The effervescent solution resulted in a sudden decrease in heart rate from 76 bpm to 45 bpm. The solution was immediately aspirated and field irrigated with normal saline. The heart rate gradually improved over next 15 seconds. No further use of hydrogen peroxide was allowed. Rest of the surgical and anaesthetic course was uneventful. At the end of 5 hour surgery, anaesthetics were discontinued, neuromuscular block reversed with neostigmine and glycopyrrolate and tracheal extubation done.
TCR is a well recognised phenomenon that classically comprises bradycardia, arterial hypotension, apnea and gastric hypomotility. [3] TCR is a reproducible phenomenon and has been reported during cranio-facial surgery and during surgery with the cerebellopontine angle, petrosal sinus, orbit and trigeminal ganglion. [4] It may be produced during surgery as early as elevation of skin flap for craniotomy. [5] Stimulation of any division of the trigeminal nerve can produce this reflex. Pituitary gland is flanked by the cavernous sinuses and the maxillary and ophthalmic divisions of the trigeminal nerve are situated on the lateral wall of cavernous sinus. Stimulation of these divisions could have triggered the reflex. The second remarkable event in our patient was sudden bradycardia having a temporal relationship with hydrogen peroxide irrigation. This could have possibly been due to stimulation of the hypothalamus which is in close proximity to the pituitary gland. Parasympathetic outputs are organised in the anterior hypothalamus, sympathetic pathways in the posterior hypothalamus. It is likely that hydrogen peroxide irrigation may have generated an intense parasympathetic activity leading to bradycardia. The liberated oxygen may have mechanically stimulated hypothalamus. Since hydrogen peroxide produces an exothermic reaction on contact with organic tissues, the possibility of raised temperature in the area of hypothalamus cannot