ABSTRACT
BACKGROUND AND AIMS: Direct laryngoscopy and tracheal intubation is a noxious stimulation that induces significant stress response. Currently, this nociceptive response is assessed mainly by haemodynamic changes. Recently, analgesia nociception index (ANI) is introduced into anaesthesia practice and provides objective information about parasympathetic (low nociceptive stress) and sympathetic (high nociceptive stress) balance, which reflects the degree of intraoperative nociception/analgesia. This study evaluated the changes in ANI and haemodynamics during anaesthetic induction and intubation, and their correlation during tracheal intubation. METHODS: Sixty adult patients scheduled for elective brain tumour surgery under general anaesthesia were studied for changes in ANI, heart rate (HR) and mean blood pressure (MBP) during anaesthetic induction and intubation. This was a secondary analysis of a previously published trial. Linear mixed effects model was used to evaluate changes in ANI, HR and MBP and to test correlation between ANI and haemodynamics. RESULTS: Anaesthetic induction reduced ANI (but not below the critical threshold of nociception of 50) and MBP, and increased the HR (P < 0.001). Direct laryngoscopy and tracheal intubation resulted in increase in HR and MBP with decrease in ANI below the threshold of 50 (P < 0.001). A linear negative correlation was observed between ANI and HR; r = -0.405, P < 0.001, and ANI and MBP; r = -0.415, P = 0.001. CONCLUSION: Significant changes are observed in ANI during anaesthetic induction and intubation. There is a negative linear correlation between ANI and systemic haemodynamics during intubation.
ABSTRACT
The impact of hypertonic saline (HTS) on long term control of intracranial hypertension (ICH) is yet to be established. The current prospective randomized controlled study was carried out in 38 patients with severe traumatic brain injury (TBI). Over 450 episodes of refractory ICH were treated with equiosmolar boluses of 20% mannitol in 20 patients and 3.0% HTS in 18 subjects. Intracranial pressure (ICP) was monitored for 6days. ICP and cerebral perfusion pressure (CPP) were comparable between the groups. The mannitol group had a progressive increase in the ICP over the study period (p=0.01). A similar increase was not seen in the HTS group (p=0.1). The percentage time for which the ICP remained below a threshold of 20 mmHg on day6 was higher in the HTS group (63% versus 49%; p=0.3). The duration of inotrope requirement in the HTS group was less compared to the mannitol group (p=0.06). The slope of fall in ICP in response to a bolus dose at a given baseline value of ICP was higher with HTS compared to mannitol (p=0.0001). In-hospital mortality tended to be lower in the HTS group (3 versus 10; p=0.07) while mortality at 6 months was not different between the groups (6 versus 10; p=0.41). Dichotomized Glasgow Outcome Scale scores at 6months were comparable between the groups (p=0.21). To conclude, immediate physiological advantages seen with HTS over mannitol did not translate into long term benefit on ICP/CPP control or mortality of patients with TBI.
