Original article
Clinical management for patients admitted to a critical care unit with severe sepsis or septic shock

https://doi.org/10.1016/j.iccn.2015.04.005Get rights and content

Summary

Background

The Surviving Sepsis Campaign promotes the use of norepinephrine as the first-line inotropic support for patients presenting with severe sepsis or septic shock in cases of persistent hypotension, despite adequate fluid resuscitation. However, there is little published evidence on how much noradrenaline is administered to such patients when admitted to the intensive care unit (ICU). The authors report the clinical management of this group of patients, with a special focus on the total amount and duration of norepinephrine infusion required.

Methods

A chart review of the admission records of an ICU in Hong Kong was carried out in 2013. A total of 5000 patients were screened by their diagnosis of severe sepsis or septic shock (in the admissions book) between 1 January 2011 and 31 December 2013. A total of 150 of these were identified and 100 included in the study after simultaneous in-depth reviews of their case notes by two of the investigators. The analysis covers those with severe sepsis or septic shock who required ICU admission for further care. Clinical management and outcomes were analysed.

Results

100 patients (median age 61.6; M/F ratio 2:1) met the inclusion criteria. The mean ICU stay was 13.4 days (range = 1–371). 14 patients (14%) died in the ICU, with a 28-day mortality rate of 22%. The mean period of mechanical ventilation was 6.1 days (range = 0–137). 91.5% (n = 43) of patients had been operated on immediately before admission to the ICU, and the majority of these operations had been of the emergency type (97.7%, n = 43). The mean total volumes of crystalloid and colloid administered were 3420 ml and 478 ml, respectively. The mean wean-off period for norepinephrine infusion was 4234 minutes (70.5 hours). All patients were prescribed norepinephrine for persistent hypotension despite adequate fluid resuscitation, and the mean total amount administered was 87,211 mg. Final multiple linear and logistic regression analysis showed different clinical outcomes associated with different covariates, which included: (1) total amount of crystalloid given, positively associated with the total amount and duration of norepinephrine infusion; (2) duration of mechanical ventilation, positively associated with the type of operation the patient had undergone; (3) 28-day mortality rate, positively associated with the INR.

Conclusions

What this study adds to knowledge about patients suffering from severe sepsis or septic shock: (1) the mean duration of norepinephrine infusion for septic shock patients in an ICU is almost three days; (2) the more crystalloid is required to correct hypoperfusion, the higher the dosage and longer the duration of norepinephrine infusion will be necessary; (3) the longer the patient's INR, the higher the chances of death within 28 days. Since not all patients have their body weight measured on or after admission to the ICU, we suggest further research into indirect estimation of body weight by other means, such as anthropometric measures, to guide the use of drugs and nutritional support in the ICU. In addition, APACHE scores should be included in further studies to compare the severity of the patient's condition in other research. Furthermore, since this study does not cover university hospital ICUs, we suggest that further research concerning such patients should compare and reflect similarities and differences between public and university hospitals in the territory.

Introduction

Sepsis is the clinical syndrome that results from a dysregulated inflammatory response to an infection. It exists if two or more of the following abnormalities are present, along with either a culture-proven or a visually identified infection:

  • temperature >38.3 or <36 °C

  • heart rate >90 beats/minutes

  • respiratory rate >20 breaths/minutes or PaCO2 <32 mmHg

  • WBC >12000 cells/mm3, <4000 cells/mm3 or >10% immature (band) forms.

Severe sepsis refers to sepsis plus at least one of the following signs of hypoperfusion or organ dysfunction:

  • areas of mottled skin

  • capillary refilling requiring three seconds or longer

  • urine output <0.5 ml/kg over at least one hour, or renal replacement therapy

  • lactate >2 mmol/L

  • abrupt change in mental status

  • abnormal electro-encephalographic (EEG) findings

  • platelet count <100,000 per ml

  • disseminated intravascular coagulation

  • acute lung injury or acute respiratory distress syndrome (ARDS)

  • cardiac dysfunction (i.e., left ventricular systolic dysfunction), as defined by echo-cardiography or direct measurement of the cardiac index.

Septic shock exists if there is severe sepsis, plus one or both of the following:

  • systematic mean blood pressure <60 mmHg (or <80 mmHg if the patient has baseline hypertension) despite adequate fluid resuscitation

  • maintaining systematic mean blood pressure at >60 mmHg (or >80 mmHg if the patient has baseline hypertension) requires dopamine >5 mcg/kg per minutes, norepinephrine >0.25 mcg/kg per minutes, or epinephrine >0.25 mcg/kg per minutes, despite adequate fluid resuscitation (Neviere, 2013b).

Many septic shock or severe sepsis patients require immediate critical care support. According to the Surviving Sepsis Campaign guidelines 2012 (Dellinger et al., 2013a), protocolised resuscitation of a patient with sepsis should be initiated once hypoperfusion is recognised, with the goal of keeping central venous pressure (CVP) 8–12 mmHg, mean arterial pressure (MAP) > 65 mmHg, urine output >0.5 ml/kg/hour and central venous or mixed venous oxygen saturation (Svo2)>65% (Casserly et al., 2012). For haemodynamic support, norepinephrine or dopamine centrally administered are the initial vasopressors of choice to maintain MAP > 65 mmHg (Beale et al., 2004, Dellinger et al., 2004, Dellinger et al., 2008). All these targets require support in the critical-care unit. However, despite such support, the presence of septic shock or severe sepsis is still associated with high mortality, in both developed and developing countries (Beovic et al., 2008, Cheng et al., 2007, Elias et al., 2012, Jaramillo-Bustamante et al., 2012, Khan et al., 2012, Moore et al., 2011, Pociello Alminana et al., 2007, Suka et al., 2006, Vincent and Atalan, 2008, Wang et al., 2006).

To treat patients with severe sepsis and septic shock, norepinephrine is now the first choice of many clinicians. A recent systematic review of randomised clinical trials showed the superiority of norepinephrine over dopamine for in-hospital or 28-day mortality with pooled RR: 0.91 (C.I. 0.83–0.99; p-value = 0.028) (Vasu et al., 2012), and many other studies also have similar findings (De Backer et al., 2012, Ferguson-Myrthil, 2012, Lamontagne et al., 2011, Sandifer and Jones, 2012). However, norepinephrine, like any other drug, may have considerable side effects, such as vasoconstriction in many vascular beds, decreased renal and visceral blood flow and impaired visceral organ function (Bellomo, 2003). The consequences of these side effects include gangrene of the extremities, where amputation may be required. Hence, norepinephrine should be phased out as soon as possible once the condition has stabilised. This study aims to explore (1) the clinical management of patients with septic shock or severe sepsis in a critical care unit, with a special focus on the total volume and amount of crystalloids and norepinephrine administered and (2) factors affecting the outcomes of this group of patients. Approval has been obtained from the ethics committees of both the hospital and the University.

Section snippets

Methods

A chart review of ICU admission records was carried out in 2013, at a 26-bed unit spread over two wards on the same floor, a general ICU catering for both medical and surgical cases, including trauma, orthopaedic and neurosurgical patients. The annual turnover of patients is 1800–2000, making it one of the biggest ICUs in Hong Kong.

The data collection period ran from 1 January 2011 to 31 December 2013, with patients admitted to the hospital's ICU identified from the unit's admission book.

Patient characteristics

The median age of patients was 61.6 (range 18–94) and the male-to-female ratio was 66:34 (approximately 2:1).

Admission, mortality and duration of stay in ICU

The mean stay in the ICU was 13.4 days (range = 1–371). 14 patients (14%) died there, and the 28-day mortality rate was 22%. The mean duration of mechanical ventilation was 6.1 days (range = 0–137).

Details of operations

Before or during their stay in the ICU, 47 patients underwent an operation. Of these, 43 (91.5%) had an operation immediately before admission, with the remaining four (8.5%) having a percutaneous

Discussion

This study describes the clinical management outcomes of patients in Hong Kong with severe sepsis or septic shock requiring admission to the ICU, giving local and international healthcare professionals a clearer view of the situation in the territory.

The median age of patients in our study was 61.6, with a distribution skewed towards the left, meaning a large proportion of patients aged over 60. This is consistent with other studies related to patients with severe sepsis or septic shock

Conclusion

In summary, we hope this study may provide local and international healthcare workers with more information about the clinical management of ICU patients in Hong Kong suffering from severe sepsis or septic shock, and about their subsequent clinical outcomes. What this study adds to the present body of knowledge about such patients includes: (1) the mean duration of norepinephrine infusion in ICU for septic shock patients is almost three days; (2) the more crystalloid is required to correct the

Funding

The authors have no sources of funding to declare.

Conflict of interest

The authors have no conflict of interest to declare.

References (32)

  • R.P. Dellinger et al.

    Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock

    Crit Care Med

    (2004)
  • R.P. Dellinger et al.

    Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

    Intensive Care Med

    (2008)
  • R.P. Dellinger et al.

    Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2012

    Intensive Care Med

    (2013)
  • R.P. Dellinger et al.

    Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2012

    Crit Care Med

    (2013)
  • N. Ferguson-Myrthil

    Vasopressor use in adult patients

    Cardiol Rev

    (2012)
  • A. Gray et al.

    The epidemiology of adults with severe sepsis and septic shock in Scottish emergency departments

    Emerg Med J

    (2013)
  • This study was performed in Intensive Care Unit of Tuen Mun Hospital, 23 Tsing Chung Koon Road, Tuen Mun, Hong Kong: SAR.

    1

    Tel.: +852 24637939.

    2

    Tel.: +852 28192633.

    View full text