Hemoglobin drop after anesthesia in craniosynstosis: Dilemma of operate or not to operate.

An infant with craniosynostosis for craniectomy and cranial-vault remodelling was detected to have very low hemoglobin (6.8 gm%) after induction of anesthesia. This posed a dilemma whether to proceed with or abandon the surgical procedure. The case was postponed and was rescheduled for surgery one week later with hope that his hemoglobin would rise during this period. However, even before second anesthesia his hemoglobin level was found to be unchanged. Meticulous anesthesia management resulted in uneventful surgical procedure.

INTRODUCTION

Craniosynostosis occurs as a result of premature fusion of one or more fibrous sutures of the skull. This results in skull deformity because of restricted skull growth.Elevated intracranial pressure secondary to rapid brain growth within the rigid skull results if multiple sutures are fused. Hydrocephalus is present in 5% to 10% of them with craniofacial sutures fusion.[1] It is estimated the condition affects 1 in 2000 live births. Parents usually bring the infant to clinician for the cosmetic considerations. Surgical correction of the skull deformity is the only option. An early surgical intervention results in cosmetic improvement and also allows adequate brain development. In presence of craniofacial deformities,such as Crouzen's syndrome, facial sutures are also involved, which presents with additional problems of airway management.[1] Because the infant scalp is highly vascular, the open surgical procedure often results in massive blood loss and may need transfusion of 20% to 500% of infant's blood volume.[23] In view of anticipated massive blood loss during surgery it is imperative that the patients do not have pre-existing anemia. Occasionally though patient is admitted in the hospital in good physical condition and normal haemoglobin level, may develop anemia due to various reasons while waiting for corrective surgical procedure. Any improper anesthetic management during major surgery on such anemic infant may result in a catastrophe. Thus low haemoglobin missed during preanesthesia examination and detected only on the operation table poses a dilemma of whether to operate or postpone the procedure. Here, we present a case of craniosynostosis for craniectomy and fronto-orbital advancement, who was detected to be severely anemic after induction of anesthesia.

CASE REPORT

An 8 months old male infant, weighing 6 kg, was admitted in the neurosurgical ward for correction of craniosynostosis along with fronto-orbital advancement. On examination, he had microcephaly, osteopectosis, bilateral optic nerve atrophy, and hydrocephalus. Mother gave history of infant developing post traumatic seizures for which he was on anti convulsants; phenytoin and levatrocetam. His preoperative investigations (hemoglobin, complete blood count and serum biochemistry) were within normal limits. He underwent general anesthesia for insertion of ventriculo-peritoneal shunt for hydrocephalus. His airway management was difficult, and because of high location of larynx, tracheal intuabation was also difficult. Anesthesia course during the surgical procedure was uneventful. He desaturated after extubation and therefore, was reintubated and transferred to pediatric intensive care unit (PICU) for further management. In the PICU the infant developed septicemia for which he received appropriate treatment and made full recovery.

A week after his recovery from septicemia he was scheduled for correction of craniosynostosis and frontal bone advancement. On examination the infant was fully conscious with normal systemic examination [Figure 1]. Apart from low haemoglobin (9.7 gm%), his all other investigations were in normal range. In the operation room after attaching routine monitors (ECG, pulse oximetr, and non invasive blood pressure), anesthesia was induced with fentanyl, propofol and tracheal intubation facilitated with rocuronium. After anesthesia induction two peripheral venous lines (each 20G) were secured. Right radial artery and right internal jugular vein was cannulated for invasive arterial pressure and CVP monitoring, respectively. A blood sample was drawn from arterial line to measure baseline blood gases and hemoglobin level. The blood sample showed a hemoglobin of 6.8 gm%. Suspecting an error in sampling or laboratory error,another blood sample was taken and this too showed the same hemoglobin level.The situation was informed to the chief surgeon who in turn discussed the risks of major surgery associated with low hemoglobin with the infant's father. The later decided against the surgery and the operation was deferred.

Figure 1

Pre and post operative 3 dimensionally reconstructed CT scans of the patient, depicting pan sutural craniosynostosis and most significantly shallow retracted orbital rims. 2 days postoperatively, Orbital bar advancement is evident in addition to frontal bone remodelling. 3 months post operatively futher bone growth and progressive closure of the bony defects have occurred faster than expected due to the child's condition (Osteopetrosis).

One week later the case was discussed by the surgeon and anesthesiologist and it was decided to perform the procedure with the same haemoglobin level. Intraopearative monitoring consisted of continuous ECG, pulse oximetry, invasive arterial blood pressure, CVP, end tidal carbon dioxide, temperature and urine output, in addition to blood loss estimation. Patient's temperature was maintained with forced warm air blanket. Patient lost approximatel 400 ml of blood and was transfused three units, each of 150cc of whole blood, during the operation. Total surgical duration was 10 hours. Patient was not extubated and transferred to PICU for further management. In the PICU his pulse rate was 190 beats per minute (BPM) and blood pressure of 130/70 mmHg. He was given fentanyl and midazolam which decreased his heart rate to 160 BPM. His coagulation profile was found to be deranged which was corrected with fresh frozen plasma.

During the PICU stay the infant developed bilateral lung wheeze with suspicion of tracheal tube block/atelectasis (90% oxygen saturation on 100% oxygen) for which flexible bronchscopy was conducted and tracheal tube was replaced with a new one. Mechanical ventilation was continued and broad spectrum antibiotics administered to treat underlying infection. Mechanical ventilation was discontinued after two weeks and trachea extubated.He was discharged home in good physical condition.

DISCUSSION

Dysmorphic features of craniosynostosis,if left untreated,may impact brain growth and cause cognitive impairment. Peroperative concerns in craniosynostosis chiefly center around massive blood loss, and abnormal surgical position for surgery, though many authors have cautioned of venous air embolism also.[4] Amount of blood loss dependes on number of sutures involved and extent of surigacl repair. Massive blood loss usually results during cranio-vault remodelling procedures. Blood loss as high as 55 ml/kg was reported by van Uiterta and colleagues[5] in a retrospective analysis. They also observed that long duration of surgery and lower body weight were associated with significantly more blood loss and red cell transfusion. Our patient too lost approximately 70ml/kg of blood over 10 hours duration of the procedure Dahmani and colleagues[4] found continuous autologous transfusion very effective in these surgical procedures. Massive transfusions have their own share of complications including, dilutional coagulopathies,[6] and even cardiac arrest from transfusion related hyperkalemia.[7] A massive blood loss assume more significance in presence of pre-existing anemia, as in our patient. To reduce the quanity of blood loss and transfusion, various authors have employed different strategies including, preoperative acute hemodilution,[8] hypotensive anesthesia,[9] intraoperative continuous infusion of tranexamic acid,[10] fibrinogen adminstiration,[11] etc. Administration of tranexamic acid and fibrinogen would have benefitted our anemicr patient but they were not available, while hypotensive anesthesia or hemodilution have potentials to increase morbidity in presence of anemia. Recent introduction of endoscopically assisted craniectomy technique which is less invasive and decreases time patients spend under anesthesia, the need for blood transfusion, and length of hospital stay, will prove a boon for this procedure.[12]

The major mistakes in our management of case were we relied on laboratory investigations which were one week old, more so since this patient was subjected to ventriculo-peritoneal shunt about one week ago. Furthermore, infant's hemoglobin was not raised to an acceptable level by preoperative transfusion while waiting for surgery subsequent to previous cancellation of the surgical procedure.

In conclusion, we recommend that during pre anesthesia check up anesthesiologists should not rely on old laboratory reports especially, if the patient had undergone a surgical procedure, howsoever minor, before a major surgery.